evidence is inconclusive that forced air warming devices increase surgical site contamination or infection authors ashley bonner, bsn, rrna school of nurse anesthesia harris college of nursing and health sciences, texas christian university, fort worth, texas. correspondence: a.bonner@tcu.edu mark welliver, crna, arnp, dnp associate professor of professional practice school of nurse anesthesia harris college of nursing and health sciences, texas christian university, fort worth, texas. correspondence: m.welliver@tcu.edu acknowledgements this review was conducted in partial fulfillment of the requirements for the doctor of nursing practice school of nurse anesthesia at texas christian university. i want to acknowledge mark welliver, crna, arnp, dnp, faculty of tcu school of nurse anesthesia for expert advice and guidance in this assignment. abstract the greatest degree of heat loss in surgery is during the first hour after induction of general anesthesia. intraoperative hypothermia poses great risks for the patients and their recovery. the use of forced air warming devices has been well studied and shown to maintain patient normothermia. there is concern that forced air warming disrupts operating room airflow and contaminates the sterile field leading to surgical site infections. a literature search was performed using embase, web of science, aej clinical key and nursing at ovid joanna briggs institute (jbi). five articles were found comparing the contamination risk of forced air warming with other warming technologies. the synthesis review found insufficient evidence to suggest delayed or discontinued use of forced air warming. the studies’ lack of data showing patient surgical site contamination and inability to conclude that the forced air warming devices actually caused surgical site infections due to intraoperative contamination do not support a change to clinical practice. as the greatest amount of patient heat loss is during the first hour of anesthesia, the use of forced air warming devices at this time is supported as opposed to delaying use due to unsupported concerns of surgical site contamination. keywords forced air warming, intraoperative, contamination, infection, normothermia introduction hypothermia is an issue during the perioperative period and is caused by various factors. anesthetics such as volatile agents, intravenous (iv) agents, and spinal/epidural anesthesia impair the patient’s thermoregulation capabilities.1 within the first hour of administering anesthesia, the patient’s core temperature drops significantly due to redistribution of body heat.1 core temperature redistribution is due to peripheral vasculature vasodilation and subsequent transfer of body heat to the environment. radiation of body heat is the primary mechanism of heat loss followed by convection, conductance, and evaporation. as with all diffusions, the greater the difference in concentration, pressure, or heat energy, the greater the net movement. peripheral vasodilation also increases the surface area exposure of body heat promoting net diffusion. cold operating room (or) temperatures, infusion of cold iv fluids and open body cavities contribute to heat loss experienced by the patient. perioperative hypothermia is associated with postoperative mortality, bleeding, platelet inhibition or dysfunction, shivering, and a decrease in neutrophil activity causing infections.1 active air warming is known to be superior to passive warming in preventing intraoperative hypothermia. forced air warming (faw) has shown to be most effective compared to other warming or heat conserving methods in maintaining core body temperatures, reduced shivering, reduced morbidity caused by infection and bleeding and shorter length of hospital stay overall.1 evidence supports the use of faw preoperatively and intraoperative, especially during the first hour after general anesthetic induction, a critical point of heat redistribution from the core body to the periphery. during this time, the surgical site is exposed and prepped for a sterile field. the or air is prudently directional and filtered during surgery to prevent the contamination of sterile equipment and surgical sites. unidirectional downward airflow is used in many operating suites, specifically orthopedic, to deter unwanted pathogens from surgical sites and sterile areas.2 there is concern that faw systems may increase the risk of infection by airborne-microbial emissions directly from the device or by disrupting laminar airflow in the or.2 therefore, it is important to evaluate active warming devices to determine if one contributes to increased contamination. does faw, compared to other warming devices, increase intraoperative infection risks by interrupting or ventilation and/or releasing microbial emissions resulting in a contaminated surgical site? methodology a literature search was conducted using embase including medline, web of science™, clinical key and nursing@ovid (joanna briggs institute) to find articles discussing intraoperative contamination possibilities of forced air warming systems and its counterparts. the keywords used were “forced air warming,” “operating room*,” “contamination” and “infection.” keywords were combined using or and and to limit the results. the final search was “(forced air warming) and (operating room*) and aej (contamination or infection).” nine out of 16 articles found in embase were relevant to the topic. seven were excluded because they addressed only the use of an active warming device for the prevention of perioperative hypothermia and discussed the reason for laminar airflow and its proper use in the or. three additional studies were excluded because of unavailable data. the web of science database provided 9 total articles using the same keywords; however, only 2 were unique. four of the 9 were repeats from the previous embase search, and 3 were excluded after reviewing the abstracts for relevance. in clinical key, a search using the terms yielded a total of 120 articles. after reviewing these abstracts, it was determined that there were no new articles. two additional studies were obtained from the bibliographies of appropriate articles. a total of 10 articles were used for this review. literature review legg et al compared two warming devices against a control of no warming device.2 the devices, a faw blanket (bair huggertm) and a radiant warming blanket (hotdog® were applied to a volunteer’s torso.2 the purpose of the study was to determine if these devices increased the temperature and the number of simulated bacterial particles present at the surgical site.2 a controlled simulated operation was set up with one surgeon present in the theatre.2 temperature measurements were performed before and 30 minutes after warming and a handilaz® counter was used to count the number of particles.2 the handilaz counter is a handheld device that measures particles in the air using laser and photo detector technology, the particles are counted and sorted according to size.2 each mode of measurement was repeated 5 times using each device and the control.2 the operating theatre was unable to simulate a true surgical environment because it lacked the usual influence of equipment, personnel, and their movements during normal working conditions. although the experiment resulted in a significant mean increase in temperature (1.1°c vs. 0.4° c, p<0.0001) and concentration of particles (1,038.2 vs. 274.8, p=0.0087) when using a faw device, conclusions cannot be made that this would cause an increased intraoperative risk of surgical site infections.2 a replicated full factorial design was performed by belani et al to determine whether a faw blanket (bair huggertm model 540; arizant heathcare) or a heat-conducting fabric blanket (hotdog® model b110; augustine temperature management) positioned over the torso disrupted ventilation in the or causing surgical site contamination.3 the conducting fabric was powered using low voltage electricity. neutrally buoyant detergent bubbles, with a 4-mm average diameter, were produced using a generator specifically designed for the purpose of air current visualization.3 an operative theatre was set up for a total knee replacement in an orthopedic or with laminar downward ventilation airflow.3 an anesthesia practitioner was placed at bedside with an anesthesia drape at high or low position. neutrally buoyant bubbles, which simulate skin cell fragments and free-floating bacteria, were introduced at the head of the mannequin to track air movement under the sterile drape. timelapse photography was used at 10-second increments to measure bubbles present at the surgical site.3 faw had a large increase in bubbles measured at the surgical site compared to conduction fabric (132.5 vs. 0.48, p=0.003) and the controlled condition of no warming device (0.01, p=0.008).3 conduction fabric did not have a significant difference in bubble measurement compared to the control (p=0.87).3 although the simulation environment of this study found air current disruption with faw a causation or correlation to surgical site contamination or infection is unable to be made. a conflict of interest existed with this study as the authors received research funding, consultant fees, and salary from augustine temperature management, the company that manufactures the non-faw device conductive fabric blanket used in the experiment.3 a simulation study by mcgovern et al also used neutrally buoyant bubbles to identify disruption of airflow comparing a faw device (bair huggertm model 540; arizant healthcare) and the hotdogtm conductive fabric blanket (augustine temperature management).4 this study found the similar results as belani et al.3 of the two devices, the faw device resulted in higher measurements of bubbles (68 vs. 0, p< 0.001) in the simulated surgical site area of the mannequin. in addition, this study included retrospective collection of data from joint replacement surgeries during a 2.5 year period.4 data included infections that presented within 6 months after surgery. the study found that 1,066 patients had surgery using the faw device and 371 used the conductive fabric.4 a higher incidences of joint infections was found when faw was used (odds ratio 3.8, p=0.024) and a significant reduction in infection rates was found with conductive fabric versus faw (0.8% vs. 3.1%, p=0.024).4 the major weakness in the joint infection data collection was that the prophylactic antibiotic regimen changed multiple times over the 2.5 year time period.4 incomplete recording of important predictors of deep infections such as blood transfusions, obesity incontinence and patient fitness level before surgery further weaken the study. this is the first evidence found that links (albeit weakly) faw to surgical site infections. sessler et al conducted a study in 2011 using faw in a two separate simulated or environment to determine disruption of air quality. the bair huggertm faw model 522 upper body blanket and model 635 underbody blanket were tested in three conditions: baseline with the blowers off, blowers on with cool ambient air, and blowers on with heat.5 a conscious volunteer was positioned on the or table and 6 heated mannequins were positioned around the or to simulate or personnel. the use of nonmoving heated mannequins allowed convection currents but prevented airflow disturbance by human movement in an effort to isolate faw airflow disruption. a particle detector was placed over the volunteer’s abdomen and a vapor generator allowed for visualization of airflow.5 the equation for the log reduction of particle concentration at the test point in relation to the particle load in the room was pex = -log(cx/cref). 5 log reduction of 2.0 was indicated as the threshold minimum value by deutsches institut für normung (din) standards developed in germany to calculate the function of laminar airflow. the worst of 5 measurements were calculated for each device. by comparing the 3 different testing conditions to the baseline particle load in the or, faw was found to have no compromising effect on laminar airflow (3to 5-log reduction).5 a supporting author of the study received research funding from arizant healthcare, manufacturer of bair hugger.5 in 2011, albrecht et al evaluated the bair hugger model 505 and included the evaluation of 2 generations of intake filters by the same manufacturer, the newest 200708d model, and the current 200708c model.6 five of each filter model were tested according to industry standards using a sodium chloride aerosol.6 fifty-two of the faw models used in real or settings were assessed for intake filter retention efficiency, performance in the or, faw blower-generated particles, and air path microbial colonization of the internal distal hose.6 the newer model filter’s efficiency was lower than that of the current model, resulting in faw blower contamination emissions of 61.3% vs. 93.8%.6 buildup of internal airborne contamination largely depends on the environment in which the device is used; 58% of the 52 blowers from 11 hospitals produced contaminants.6 this was the first study to evaluate the relationship of intake filter performance with faw blower contamination. microbial-contaminated emissions in the or are a potential clinical risk. recently, reed joined the authors of the belani et al3 study and conducted a similar experiment on the most current and widely aej used faw device. the bair hugger faw model 750 was evaluated on four categories: intake filter efficiency, intake filter performance in the or, production of airborne contaminates, and internal air path microbial colonization.7 we tested the intake filter’s efficiency by counting sodium chloride particles the filter captured during a 10-minute challenge.7 laser particle counts were calculated from 23 faw blowers after hours in the or of a hospital to test the filters’ efficiencies.7 we replaced the filters on the same 23 faw devices, measured the particle counts downstream, and obtained swabs from the internal air path surfaces to determine contamination emission and microbial colonization.7 the filter challenge revealed only 63.8% efficiency and, by removing and challenging all 23 intake filters, it found only minute differences in filtration efficiency and showed that the intake filters were performing to specifications in the or.7 furthermore, 96% of the faw devices produced contamination emissions, and 100% revealed the presence of microorganisms from the distal end of the blower.7 the study found that faw devices inadequately filter particles, allowing microbial colonization distal to the filter. in a nonrandomized comparison study, dasari et al compared the temperature warming effects of the bair hugger, an underbody resistive mattress (indithermtm, inditherm medical, rotherham, uk), and the hotdog conductive fabric system.8 the hypothesis was that increased temperatures caused by warming systems can disrupt laminar flow ventilation by creating convection currents at the surgical site. to test this hypothesis, warming devices were placed on the lower body of a mannequin, and temperature measurements were recorded in 60-second intervals using 24 thermostats at various heights above the or table.8 in an environment simulating an orthopedic or, temperatures were measured during 3 distinct periods over 5 different areas of the mannequin: the right and left shoulder, abdominal area, and right and left knee.8 the “control” time was the 20-minute period before warming, the “transition” was the 10-minute period after the device turned on, and the “steady state” was the 20-minute period after the device was turned on, when the device had thermally balanced.8 this technique was performed for each device. the data was used in an analysis of variance model to formulate results.8 faw caused the greatest temperature increase from the control period versus the conductive blanket (+2.73 (0.7)°c; p<0.001) or resistive mattress (+3.63 (0.7)°c; p<0.001) at the mannequin’s abdominal surgical site.8 at shoulder level, there was no significant difference in temperature among any of the devices.8 the effect of increased heat at the surgical site in terms of infection remains unknown. huang et al conducted an experiment during 16 abdominal vascular prosthetic graft insertion procedures using bair hugger faw systems.9 bacterial counts in the air and wound specimens were collected and compared at the start and end of surgery.9 the mean number of colonies of microbial growth from the or air and the exhaust fan near the axillae of the patient decreased from the start of the operation to the end (mean reduction, 36.4%; p<0.01).9 these results could have been due to the movement of or staff and turbulent air circulation at the beginning of the procedure compared with the end. a 6-month follow-up visit confirmed that no patients experienced postoperative or graft infections during that time.9 the author concluded the bair hugger did not contribute to bacterial contamination of the operating environment or the surgical field.9 moretti et al conducted a study similar to huang in that microbial samples were collected on agar plates using the active surface air system in the or of a procedure instead of a simulated environment. samples were collected in 3 different points: a1, a2, and a3, around the operating table in the empty or immediately before surgery, when the patient arrived, and when faw was applied.10 twenty noncemented hip implantations aej were performed; no patient had postoperative hypothermiaassociated complications or surgical infection in a 6-month period.10 however, a significant bacterial load was observed after the patient was placed on the or table and faw was applied (a1=17.8±14.5 vs. 79.2± 52.2 cfu/m3, p<0.001; a2=19.4±17.5 vs. 61.2±38.8 cfu/m3, p<0.001; a3=19.2±17.7 vs. 69.1±56.8 cfu/ m3, p<0.001).10 the results are not quantifiable but suggest that faw does not contaminate the surgical field. medical staff and movement in the or better explain the significant increase in bacteria colonization. in 1997, avidan et al conducted four experiments using 10 faw devices (9 bair huggers, augustine medical [now 3m], and 1 warm touch [mallinckrodt medical, st. louis, mo]).11 the first specimens were collected from the airflow of 10 blowers using agar plates on sterile towels in an unused or.11 control plates were used during the 5-minute intervals between turning on the blowers.11 four the 10 (40%) agar plates grew organisms, including staphylococcus epidermidis, corynebacterium, and cryptococcus albidus.11 the second experiment sought to determine if blowing warm air through a perforated blanket reduced microbial contamination. the plates were placed below the blankets for 30 minutes with the blower on, and control plates were collected for the same time with the blowers off.11 neither the control nor the experimental plates grew organisms.11 next, we used sterile swabs to collect samples from both sides of the internal filter and the inside of the proximal and distal end of the hose. the inside of the internal filter lacked growth, while the outside grew organisms such as aspergillis fumigatus and bacillus sp; both the proximal and distal hose swabs had similar growth.11 the final experiment consisted of comparing the microbial growth of the direct airstream from three blowers—with and without an attached microbial filter at the distal end of the hose. the microbial filter prevented growth after it was applied to the same blowers that grew acinetobacter lwoffii and staphylococcus epidermidis on the plates placed directly in the airstream of the warmers.11 the author states that, after this study, their hospital facility changed its policy to require the attachment of a perforated blanket when using faw in the or. synthesis studies in this review compared airflow disruption and microbial contamination of faw with that of other warming devices to identify infection risk associated with these devices. ten of the studies 2-8,11 were experimental designs, 2 involved human subjects,9,10 and 1 included retrospective hospital surgical infection rates.4 although the studies by albrecht, reed, and huang found that microbial contaminates may be present in faw device hoses, its clinical significance has been questioned by the lack of data showing surgical site contamination, causative increased infection rates, and a specific study that showed that, despite microbial presence at the faw device distal hose, no air contamination from the perforated warming blanket required for patient use was found.11 only a retrospective study found an increased infection rate over a 2.5-year period when faw devices were used versus a convection device, but the causative variables were not isolated, and prophylactic antibiotic regimens were not controlled. considering that high-efficiency particulate air filtration improves microbial entrapment and that microbial growth on faw device hoses occurs, regular changing of faw device filters may be beneficial but cannot be recommended. hose decontamination is also a consideration, but further study is necessary to determine its efficacy. randomized controlled studies in multiple facilities comparing faw and other patientwarming devices should collect data on surgical site or implant infection rates and correlate it with the causative pathogen. conclusion the studies in this review primarily focused on the disruption of or airflow and microbial contamination and emissions aej of faw devices and could only infer potential effect on surgical site contamination. no studies have demonstrated that faw contributes to a greater risk of surgical site infection. in addition, most studies were funded or conducted by researchers affiliated with two competing device manufactures, introducing bias. the clinical decision to avoid faw during the immediate period after induction of anesthesia and during surgical prep must be weighed against the well-documented risk of core temperature redistribution, which is at its worse during this time. warming of the patient during the first hour of anesthesia is important, and maintenance of normothermia has become a standard of practice. hypothermia has been associated with increased infection rates.15 this review found limited data to support limiting faw perioperatively. if faw is the only method available to maintain patient temperature, its avoidance at the beginning of the operative period is not advised. if other warming methods are available and effective, they may be substituted. evidence does not support terminating the use of faw in the or environment, nor does it support delaying the use of faw until surgical drapes are placed. because it may take as long as an hour to prepare and drape a patient for surgery, the heat loss during this time can be significant. until definitive evidence is found to advise otherwise, the use of warming devices, including faw, is recommended without change from current practice. references 1 moola s, lockwood c. effectiveness of strategies for the management and/or prevention of hypothermia within the adult perioperative environment. int j evid based healthc. 2011;9(4):337-345. 2 legg aj, cannon t, hamer aj. do forced air patientwarming devices disrupt unidirectional downward airflow? j bone joint surg br, 2012;94(2):254-256. 3 belani kg, albrecht m, mcgovern pd, reed m, nachtsheim c. patient warming excess heat: the effects on orthopedic operating room ventilation performance. anesth analg. 2013;117(2):406-411. 4 mcgovern pd, albrecht m, g belani k, et al. forced air warming and ultra-clean ventilation do not mix: an investigation of theatre ventilation, patient warming and joint replacement infection in orthopaedics. j bone joint surg br. 2011;93(11):1537-1544. 5 sessler di, olmsted rn, kuelpmann r. forced-air warming does not worsen air quality in laminar flow operating rooms. anesth analg. 2011;113(6):1416-1421. 6 albrecht m, gauthier r, belani k, litchy m, leaper d. forced air warming blowers: an evaluation of filtration adequacy and airborne contamination emissions in the operating room. am j infect control. 2011; 39(4):321-328. 7 reed m, kimberger o, mcgovern pd, albrecht mc. forced air warming design: evaluation of intake filtration, internal microbial buildup, and airborne-contamination emissions. aana j. 2013;81(4):275-280. 8 dasari kb, albrecht m, harper m. effect of forced air warming on the performance of operating theatre laminar flow ventilation. anaesthesia. 2012;67(3):244-249. 9 huang jk, shah ef, vinodkumar n, hegarty ma, greatorex ra. the bair hugger patient warming system in prolonged vascular surgery: an infection risk? crit care (london, england). 2003;7(3):r13-r16. aej 10 moretti b, larocca amv, napoli c, et al. active warming systems to maintain perioperative normothermia in hip replacement surgery: a therapeutic aid or a vector of infection? j hosp infect. 2009;73(1):58-63. 11 avidan ms, jones n, ing r, khoosal m, lundgren c, morell df. convection warmers-not just hot air. anaesthesia. 1997;52 (11):1073-1076. 12 mahoney cb, odom j. maintaining intraoperative normothermia: a meta-analysis of outcomes with costs. aana j. 1996;67(2):155-163. 13 melnyk m, fineout-overholt e. evidence-based practice in nursing & healthcare: a guide to best practice. philadelphia, pa: lippincott, williams, and wilkins. 2005:10. open-globe eye injuries and choice of muscle relaxant: a review of the evidence authors joelle benoit, bsn, rrna harris college of nursing and health sciences, texas christian university, fort worth, texas. correspondence: j.benoit@tcu.edu mark welliver, crna, arnp, dnp associate professor of professional practice school of nurse anesthesia harris college of nursing and health sciences, texas christian university, fort worth, texas. correspondence: m.welliver@tcu.edu acknowledgements this review was conducted in partial fulfillment of the requirements for the doctor of nursing practice school of nurse anesthesia at texas christian university. i want to acknowledge mark welliver, crna, arnp, dnp, faculty of tcu school of nurse anesthesia for expert advice and guidance in this assignment. abstract a goal of treatment of open-globe eye injuries is preventing rises in intraocular pressure and the resulting loss of vitreous humor fluid from the eye globe. surgical repair of these injuries often requires general anesthesia and tracheal intubation. normal intraocular pressure is 10-22 mm hg, with variations between daytime and nighttime values. factors such as eye muscle structure, fluid volume in the eye, overall hemodynamic status, blood acidity, and mechanical pressure collectively contribute to fluid pressure within the eye. one factor that has been shown to be strongly correlated with increased intraocular aej pressure is elevated venous pressure with physiological conditions during tracheal intubation (eg, straining, coughing, bucking). to determine intubation best practices, we reviewed the literature on succinylcholine, a depolarizing neuromuscular blocking agent, and nondepolarizing neuromuscular blocking agents. research and case reports have not shown an association between the loss of ocular contents and succinylcholine administration. however, succinylcholine has been associated with increased intraocular pressure after administration and intubation. nondepolarizing neuromuscular blocking agents, particularly rocuronium, administered before or instead of succinylcholine, have been found to attenuate the rise in intraocular pressure after induction and intubation. keywords succinylcholine, nondepolarizing neuromuscular blocking agents, muscle relaxant, tracheal intubation, intraocular pressure, open-globe injury. introduction a goal of treatment of penetrating injuries is avoidance of intraocular pressure (iop) elevation to prevent loss of vitreous humor fluid from the eye globe.1 when penetrating open-globe injuries occur, surgical repair often necessitates general anesthesia and tracheal intubation. normal iop is maintained at 10-22 mm hg, with variations in daytime and nighttime values. multiple factors, including the structure of eye muscles, fluid volume in the eye, overall hemodynamic status, blood acidity, and mechanical pressure, contribute to the amount of fluid pressure within the eye.2 one particular factor that has shown a strong correlation with increased iop is an elevation in venous pressure with physiological conditions that occur during tracheal intubation (eg, straining, coughing, bucking).2 patients presenting with ocular trauma involving an open-globe injury require exquisite care and attention from anesthesia personnel to minimize elevations in iop above normal ranges and prevent the loss of vitreous humor and, potentially, loss of the contents of the eye. questions concerning the use of succinylcholine, a depolarizing neuromuscular blocking agent (nmba), for intubation require a review of the evidence to determine best practice for this patient population. the availability of alternative nondepolarizing nmbas (eg, rocuronium) for intubation has created an opportunity for improved practice. history succinylcholine is considered the gold standard of nmbas when the need for rapid sequence intubation (rsi) is present. succinylcholine allows for quick, optimal intubating conditions when patients present with a need for immediately securing the airway and emergent surgical interventions.3 over time, succinylcholine has continued to be associated with an increase in iop. this association has been through anecdotal professionalto-professional reports and, recently, a single non-confirmatory case study that discusses the loss of vitreous humor after its administration presumably due to brief muscle fasciculations.3,4,5 libonati’s6 retrospective study of 250 patients having undergone ocular surgery found that succinylcholine did not cause loss of vitreous humor in any of their patients. having been cited 107 times in scholarly literature reflects growing questioning of the belief against succinylcholine’s use in this patient population. alternatively, nondepolarizing nmbas at above normal doses, allow for comparable intubating conditions to succinylcholine with the theoretical advantage of reducing iop due to their extraocular muscle relaxing effects with fasiculations.1 anesthesia providers are faced with an evidence-based practice conundrum when determining which nmba to administer for tracheal intubation in this particular patient population. therefore, this evidence-based review sought to answer the question; in adult patients with open-globe ocular injuries does the administration of succinylcholine for intubation aej compared to nondepolarizing nmbas cause increases in iop and support the theoretical risk of extrusion of aqueous humor? literature review an initial, in-depth literature search was conducted without limit to date, utilizing pubmed, embase, clinical key, proquest nursing and allied health source, and web of knowledge databases to locate scholarly literature comparing the administration of nondepolarizing nmbas with succinylcholine in patients undergoing surgical repair for an open-globe injury. the key terms used included “succinylcholine,” “suxamethonium,” “open-globe injury,” “eye injury,” “intraocular pressure,” “neuromuscular blocking agents,” and “aqueous humor.” the results from the search did not meet the inclusion criteria, specifically the disclosure of loss of aqueous humor. therefore, a second literature search was conducted with a broader approach. a combination of key terms was utilized for each database with the use of and. the pubmed search was performed with a combination of “open-globe” and “succinylcholine” and “intubation” and generated 16 results. embase was searched with a combination of “succinylcholine,” “ocular aqueous humor” and “iop,” based off of predicted search terms and resulted in 12 scholarly articles for review. a web of science topic search was conducted with the combination of “open-globe” and “succinylcholine” that produced 15 articles. the proquest database generated predicted search terms, and “eye injur*” and “succinylcholine” were combined to deliver 9 relevant articles. clinical key was searched with the combined key terms “eye injuries and succinylcholine” and refined to anesthesia specialty, and the database produced 29 results. limiters were applied to each database to include only english-language articles and adult populations (18+ years of age). a cumulative total of 85 articles resulted. after the application of inclusion criteria specific to adult patients undergoing surgical procedures requiring intubation with intraocular pressure monitoring, the administration of nondepolarizing nmbas and/or the administration of succinylcholine, a total of 7 articles were found relevant to the purpose of this review. in an attempt to locate additional studies, a google scholar search was conducted which produced similar findings. the case study by amadasun and isesele4 describes a 34-yearold trauma patient admitted to an emergency department with intra-abdominal injuries, limb injuries, and a laceration of the right cornea. the patient required emergency surgical intervention of the abdominal injuries, and the injured eye was dressed with gauze and strapped prior to entering the operating room. once induction agents were administered, cricoid pressure was applied and 100 mg succinylcholine was administered. an elevation in blood pressure was noted following intubation, and the patient required additional anesthetic agents post intubation upon the return of spontaneous breathing.4 direct visualization of the injured eye was not performed after the dressing application until the completion of the abdominal surgical procedure, and there is no mention of the elapsed time between interventions.4 after laparotomy, the ophthalmologists reported for the corneal repair, only to find the vitreous humor had been extruded.4 mechanical external pressure application to the injured eye such as touching the eye or the structures around the eye, elevation in blood pressure, and tracheal irritation (in this case, external cricoid pressure and intubation) have been shown to significantly elevate iop, which could have led to the loss of intraocular contents with an open open-globe injury.2 a major weakness of this case report is the lack of visual observation of the actual extrusion to identify a cause and effect. other weaknesses include the application of mechanical pressure, intubation procedures, an abdominal surgical procedure with undisclosed measurement of continual neuromuscular monitoring, and a lengthy period with multiple opportunities for other aej contributing factors to the vitreous humor extrusion. therefore, succinylcholine administration cannot be definitively identified as the cause for the loss of ocular contents in this patient. lavery et al7 conducted a randomized controlled study that compared iop readings in 30 patients following the administration of atracurium, a nondepolarizing nmba, or succinylcholine. ten of the 30 patients were administered induction agents that excluded muscle relaxants followed by laryngoscopy and tracheal intubation. once a steady state of anesthesia and hemodynamics was achieved, either 0.5 mg/kg of atracurium or 1.0 mg/kg of succinylcholine was administered. iop readings were obtained at 1-minute intervals for 5 minutes and once more at 10 minutes post intervention. the intervention strategy allowed for the comparison of the two agents under conditions unaffected by extraneous factors such as tracheal irritation or hemodynamic instability. the findings of the steady state groups indicated that succinylcholine administration was responsible for a significant (p<0.025) elevation in iop regardless of tracheal manipulation. the remaining 20 patients were administered either a combination of atracurium 0.75 mg/kg and thiopentone 5 mg/kg or succinylcholine 1.0 mg/kg and thiopentone 5 mg/kg prior to tracheal intubation, which was performed with cricoid pressure application. iop readings were then obtained over 1-minute intervals for 5 minutes post intubation. thiopentone produced a significant (p<0.025) decrease in iop post induction; however both groups displayed a significant (p<0.005) elevation in iop immediately following tracheal intubation. in the atracurium group, iop readings did not breech baseline values. immediately following intubation, the succinylcholine group displayed a significant (p<0.05) increase in iop readings that remained above baseline readings for 2 minutes. the results from the steady-state groups and the thiopentone groups support the practice of avoiding succinylcholine with open-globe injuries. vinick8 performed rapid sequence induction with tracheal intubation on 45 patients between the ages of 18 and 65 years old. three groups of 15 subjects were administered pre-inductions agents and then randomized to receive atracurium 0.5 mg/kg, rocuronium 0.6 mg/kg (a nondepolarizing nmba), or succinylcholine 1.0 to 1.5 mg/kg for neuromuscular blockade prior to tracheal intubation. intubation was attempted at 60 seconds after nmba administration. iop readings were obtained prior to induction, after the administration of an nmba, and then again 1-2 minutes after intubation. between-group comparisons were made using a two-tailed t-test, and a statistical significance was declared at a p-value of less than or equal to 0.05.8 compared with the succinylcholine group, the rocuronium group displayed a significant (p=0.046) decrease in iop from baseline post-induction, prior to intubation. the atracurium group displayed lower iop values post-induction; however they were not considered significant (p=0.667). an increase in post-intubation values was noted in all groups without exceeding baseline or reaching statistical significance. rocuronium displayed greater control of iop pre-intubation, indicating it is a viable alternative to succinylcholine administration in patients requiring intraocular surgeries with general anesthesia. smith and leano9 compared iop after induction and tracheal intubation after administration of either pancuronium 0.1 mg/ kg (n=8, test group) or d-tubocurarine 3 mg (a nondepolarizing nmba) before administration of succinylcholine 1.5 mg/ kg (n=6, control). in the test group, iop readings were obtained after the loss of eyelid reflex, 2 minutes after pancuronium administration, and then for 1-minute intervals for 10 minutes. in the control group, iop readings were obtained after the loss of eyelid reflex, 1 minute after the administration of succinylcholine (3 minutes after the administration of d-tubocurarine), and then again for 1-minute intervals for 10 minutes. the test group displayed a significant (p<0.01) decrease in iop from induction to 3 minutes post intubation.9 there was an increase in iop aej from induction to 1 minute post intubation in the control group, however it was not determined to be statistically significant. the results from smith and leano9 conclude that pancuronium lowers iop compared to succinylcholine that is pre-treated with d-tubocurarine. a comparison study of 30 patients undergoing surgical procedures, including intraocular procedures, was conducted by konchigeri et al10 to determine if pretreatment with pancuronium would attenuate an increase in iop following succinylcholine administration and tracheal intubation. prior to induction of anesthesia, the control group (n=15) received saline pretreatment, and the study group (n=15) received pancuronium 1.0 mg. a schiotz tonometer measured iop levels at baseline before the administration of succinylcholine 1.0 mg/kg, then 1 minute after the administration of succinylcholine for neuromuscular blockade, and finally, 1 minute after intubation. student’s t-test was applied, and p<0.05 was determined to be significant.10 the control group displayed elevations in iop above baseline values after succinylcholine administration and intubation, while the test group displayed elevations after intubation only. this study revealed that pretreatment with a nondepolarizing nmba is useful to attenuate iop increases post succinylcholine administration. the nondepolarizing agent will not, however, mitigate an increase in iop following direct laryngoscopy. mitra et al11 performed a randomized, double-blind control study comparing iop values in 40 patients receiving rapidsequence intubation without cricoid pressure. this study sought to contrast the effect of rocuronium 0.6 mg/kg (a nondepolarizing nmba) with that of succinylcholine 1.5 mg/kg administration for neuromuscular blockade with tracheal intubation. iop levels were obtained with schiotz tonometry at baseline, after induction, 1 minute after administration of the nmba, 1 minute after intubation, and then in 1-minute intervals for 3 minutes. student’s t-test with bonferroni correction was used to compare iop values, and p<0.05 was considered significant. in the succinylcholine group (n=20), iop values were significantly elevated above baseline (p<0.01) after intubation. iop values in the rocuronium group (n=20) did not rise above baseline values and remained significantly below baseline values for 5 minutes after induction (p<0.01). mitra et al determined that rocuronium is a good alternative to succinylcholine administration to prevent unwanted elevations in iop. a randomized, double-blind study conducted by chiu et al12 compared iop changes with the administration of rocuronium 0.9 mg/kg or succinylcholine 1.5 mg/kg during rsi and tracheal intubation. iop values were recorded prior to induction, prior to intubation, immediately after intubation, and again for 5 minutes after intubation with a keeler pulsair tonometer. statistical analysis to compare iop values was performed with a “paired t-test and two-way analysis of variance for repeated measurements…”12 and a “…probability of less than 0.05 was the criterion for statistical significance.”12 the succinylcholine group (n=15) revealed a significant increase in iop post induction and intubation (p=0.01). the rocuronium group (n=15) displayed a reduction in iop post induction (p=0.01) with an increase in values post intubation; however they did not exceed baseline values. based on these findings, succinylcholine precipitates an elevation in iop that is not seen with rocuronium administration. discussion considering the aforementioned weaknesses of the sole case report and that case reports are weak evidence in general, we focus on discussion of the research studies. most hierarchies of evidence consider randomized controlled trials and meta-analysis of randomized controlled trials as the strongest evidence. six studies were compared with a total of 189 subjects undergoing various surgical procedures requiring tracheal intubation that allowed for iop monitoring. the sample sizes ranged from 14-45 patients, with an age range of 17-70 years. aej nondepolarizing nmbas were administered to 103 subjects, of whom 50 subjects received rocuronium prior to intubation, 25 subjects received atracurium prior to intubation, 5 subjects received atracurium after intubation, and 23 patients received pancuronium. succinylcholine was administered to 86 subjects. in 5 of the 6 studies,8-12 a comparison was made between succinylcholine and a nondepolarizing nmba. sedation and induction was achieved by administering either a sedative-hypnotic agent or an opioid agent, or a combination of the two. iop measurements were obtained at different times among the studies but in general consisted of post-induction (before intubation) and post-intubation time periods. the nondepolarizing nmbas displayed a slight consistent superiority to succinylcholine with regards to reducing iop prior to intubation in three studies,7-12 although those particular agents were not able to consistently prevent an increase in iop following intubation, they were able to maintain iop levels below baseline readings or values obtained with succinylcholine. rocuronium did attenuate an increase in iop following intubation in two studies.11,12 succinylcholine is not as efficacious as the nondepolarizing nmbas at preventing elevations in iop following induction or intubation. following the administration of succinylcholine and tracheal intubation, iop readings exceeded baseline readings, and some elevations remained for up to 3 minutes. the findings of this review offer guidance when considering choice of nmba for intubation. although succinylcholine has not been found to definitively cause extrusion of vitreous humor, it remains a theoretical concern as elevations in iop occur with its administration. rocuronium is a better choice especially for rapid-sequence induction. the research clearly indicates that rocuronium is the sole paralytic agent that will consistently maintain iop readings at or below baseline levels after induction and tracheal intubation. succinylcholine administration provides for efficient intubation conditions but without consistently maintaining iop readings at or below baseline readings following induction or intubation. atracurium and pancuronium allow iop maintenance after induction and intubation; however, they may not provide successful intubating conditions, especially for rapid-sequence intubation, making them less desirable for these patients. rocuronium, at doses of 1-1.5 mg/kg, provides adequate intubating conditions comparable to succinylcholine for rapidsequence intubation. tracheal intubation has been found to be the single most important contributing factor to an iop elevation. therefore, we should focus on the risk of vitreous humor extrusion during intubation. fast, efficient, and minimally stimulating intubation is prudent in this patient population. further research should be conducted to identify any improved intubating modalities (eg, video laryngoscopy, fiberoptic light wand, high narcotic/remifentanyl induction, sympatolytics) and other methodologies that may lessen iop increases. conclusion and summary research and case reports have not been able to create a reliable association between the actual loss of ocular contents and succinylcholine administration. however, succinylcholine has been found to be associated with increased iop after its administration and after intubation. nondepolarizing nmbas, particularly rocuronium, administered prior to, or in place of, succinylcholine have been found to lessen iop elevation after induction and intubation. therefore, the research question “in adult patients with open-globe ocular injuries, does the administration of succinylcholine for intubation compared to nondepolarizing nmbas cause increases in iop and support the theoretical risk of extrusion of aqueous humor,” has been answered affirmatively with the available evidence and considering the following caveats: aej • succinylcholine administration will raise iop above baseline. • nondepolarizing nmbas do not significantly raise iop. • administration of a nondepolarizing nmba prior to succinylcholine will attenuate the rise in iop. • laryngoscopy itself is related to more significant increases in iop than either depolarizing or nondepolarizing nmbas. • clinical considerations and future research should focus on attenuating rises in iop caused by laryngoscopy. references 1 kohli r, ramsingh h, makkad b. the anesthetic management of ocular trauma. int anesthesiol clin. 2007;45(3):83-98. 2 chidiac ej, raiskin ao. succinylcholine and the open eye. opthalmol clin north am. 2006;19(2):279-285. doi:10.1016/j.ohc.2006.02.015. 3 calobrisi bl, lebowitz p. muscle relaxants and the openglobe. int anesthesiol clin. 1990;28(2):83-88. 4 amadasun fe, isesele to. vitreous humor extrusion after suxamethonium induction of anesthesia in a polytraumatized patient: a case report. case rep med. 2010;1-4. doi: 10.1155/2010/913763. epub 2010 dec 27. 5 vachon ca, warner do, bacon dr. succinylcholine and the open-globe. tracing the teaching. anesthesiology. 2003;99(1):220-223. 6 libonati mm, leahy jj, ellison n. the use of succinylcholine in open eye surgery. anesthesiology. 1985;62(5):637-640. 7 lavery gg, mcgalliard, mirakhur rk, shepherd wf. the effects of atracurium on intraocular pressure during steady state anaesthesia and rapid sequence induction: a comparison with succinylcholine. can anaesth soc j. 1986;33(4):437-442. 8 vinik hr. intraocular pressure changes during rapid sequence induction and intubation: a comparison of rocuronium, atracurium, and succinylcholine. j clin anesth. 1999;11(2):95-100. 9 smith rb, leano n. intraocular pressure following pancuronium. can anaesth soc j. 1973;20(6):742-746. 10 konchigeri hn, lee ye, venugopal k. effect of pancuronium on intraocular pressure changes induced by succinylcholine. can anaesth soc j. 1979;26(6):479-481. 11 mitra s, gombar kk, gombar s. the effect of rocuronium on intraocular pressure: a comparison with succinylcholine. eur j anaesthesiol. 2001;18(12):836-838. 12 chiu cl, jaais f, wang cy. effect of rocuronium compared with succinylcholine on intraocular pressure during rapid sequence induction of anaesthesia. br j anaesth. 1999;82(5):757-760. aej aej12 risk of complications using laryngeal mask airway versus endotracheal tube during general anesthesia in pediatric patients with upper respiratory infections: a narrative review. creation of the upper respiratory infection screening tool© and management algorithm for children presenting for general anesthesia with upper respiratory infection© megan grelson srna keywords pediatric, upper respiratory infection, anesthesia, laryngeal mask airway, endotracheal tube abstract the inflammatory process that occurs in an upper respiratory infection poses an increased risk of complications for children undergoing general anesthesia for a surgical procedure. the anesthesia providers need to decide which airway device, laryngeal mask airways or endotracheal tubes, is most appropriate and has less risk of adverse respiratory complications. a literature search was completed using embase, cumulative index to nursing and allied health literature, and the cochrane library. ten articles were found comparing the use of laryngeal mask airways and endotracheal tubes in children with upper respiratory infections. synthesis of the literature concluded that laryngeal mask airways have a decreased risk of complications compared to endotracheal tubes when used in children with recent or current upper respiratory infections. with this information, the use of a laryngeal mask airway should be considered in place of an 13volume 2, no. 1 endotracheal tube. the upper respiratory infection screening tool© and the management algorithm for children presenting for general anesthesia© were designed for quick recognition of children at high risk for respiratory complications and provide management techniques for anesthesia providers to follow. introduction upper respiratory infections (uris) are the most common illnesses among children, with most children developing 6-10 uris a year.1 these infections can be caused by more than 200 different viruses, the most common being the rhinovirus.1 children can contract any uri-causing virus through droplets in the air or from direct contact with someone who is ill.1 children are more susceptible to the illness due to their immature immune systems and close contact with other children in schools and daycares.1 the most common symptoms of uris are runny nose, cough, congestion, sore throat, and low grade fever. a complete list of symptoms can be found in table 1. upper respiratory infections are very common in children and may be present when the child is scheduled for surgery. in 1979, mcgill et al. were the first to conclude that there is an increased risk of respiratory complications in children with recent uris who undergo general anesthesia.2 the infection causes an acute inflammatory process that results in hyperreactivity of the airway smooth muscle that can last anywhere from 4 to 6 weeks.3,4,5 since this observation, anesthesia providers have disagreed on whether an elective surgical procedure should be postponed or even canceled to allow more time for the child to recover from a uri. however, by the time 4 to 6 weeks pass, a new uri may be acquired. the belief was that children with recent or current uris were at an increased risk of periand postoperational complications including laryngospasm, bronchospasm, and/or oxygen desaturation3,4,5,6,7,8,9,10 (see table 2). in 1991, cohen and cameron published the largest prospective observational study involving 1283 children with uris and aej14 20876 without.11 their research found that children presenting with uris were 2 to 7 times more likely to have respiratory complications periand postoperatively.11 upper respiratory infections increase the risk for complications in children, as seen in table 2. the infection causes an acute inflammatory process that results in hyperreactivity of the airway smooth muscle that can last anywhere from 4 to 6 weeks.3,4,5 anesthetic gases and airway manipulation can irritate the already hyperreactive smooth muscle, causing an increased risk of bronchoconstriction and laryngospasm in the child.3,4,5 an important part of the anesthesia provider’s tasks is to avoid stimulation of the larynx in the already sensitive airway, therefore decreasing the likeliness of laryngospasms and bronchospasms, which can hinder the ability to ventilate the patient.3 different invasive airway devices several different types of airway devices can be used during a general anesthetic to provide the patient the ability to spontaneously breathe or to provide positive pressure ventilation either mechanically by the ventilator or manually by the provider. the airway device is directly connected to the breathing circuit on the anesthesia machine to deliver carrier gasses to the patient. an endotracheal tube (ett) is “a large-bore catheter inserted through the mouth or nose and into the trachea to a point above the bifurcation of the trachea. it is used for delivering oxygen and other gases at or above atmospheric pressure.”12 etts were the primary means of facilitating mechanical ventilation of patients for decades and are still the primary means of securing an airway. laryngeal mask airways (lmas) were first approved by the u.s. food and drug administration in 1991 and have since been used as a passive and positive-pressure ventilation device in surgeries.13 they are a slightly less invasive way to provide 15volume 2, no. 1 an airway in patients undergoing general anesthesia and have been gaining in popularity. laryngeal mask airways are “inserted blindly into the pharynx, forming a low-pressure seal around the laryngeal inlet and permitting spontaneous or gentle positivepressure ventilation.”13 debate has begun regarding what method of airway management has the least laryngeal stimulation and lowest risk of complications to the patient.6 current research is attempting to determine which airway device, an ett or lma, is better for use in children with a current or recent uri undergoing general anesthesia. the purpose of this study is to recognize and list the symptoms of a uri, describe the changes to a child’s airway due to a uri which result in an increased risk for respiratory complications with general anesthesia, list potential complications when pediatrics with uris undergo general anesthesia, and to determine whether an ett or lma is best to use in children with current or recent uris undergoing general anesthesia. methodology a literature search was conducted using embase, cumulative index to nursing and allied health literature, and the cochrane library to find articles comparing the use of etts and lmas in pediatric patients with recent or current uris undergoing general anesthesia. the keywords used were anesthes*, surgery, pediatric*, child*, respiratory infection, upper respiratory infection, ett, endotracheal tube, lma, and laryngeal mask airway. the “*” symbol was used as a truncation symbol to search all possible spellings of a root word. keywords were combined using or and and to limit the results. the keywords were entered in the databases as (anesthes* or surgery) and (pediatric* or child) and (respiratory infection or upper respiratory infection) and (ett or endotracheal tube or lma or laryngeal mask airway). abstracts were reviewed from 131 articles with 8 relevant articles found. the reference lists from the 8 studies were reviewed, finding an additional 2 articles meeting aej16 inclusion criteria. this search was conducted in october 2010 and repeated in may 2011, september 2011, november 2011, february 2012, and march 2012, with the same articles found on each search. in order to be included in this literature review, articles had to compare etts and lmas used in pediatric patients undergoing general anesthesia with a recent or current uri. the studies had to compare etts and lmas to determine which airway device had the higher incidence of complications. editorial or opinion pieces were included, but the clinical guidelines provided in this synthesis were not made based on opinion pieces. studies including adults in the studied population were excluded in this literature review. any study that excluded children with recent or current uris was excluded. if only a single airway device (lma or ett) was studied, the article was excluded from the literature review. each article was compared to the joanna briggs institute levels of evidence (loe) rating system (table 3).14 this system is known worldwide and is used on all systematic reviews submitted to the joanna briggs institute. after reading the articles, a score from 1 to 4 was given based on the characteristics of the article content. the loe rating of each article can be seen in table 4. review of literature although there is a sufficient amount of research available on children with recent or current uris undergoing anesthesia, there is not much research on what is the best airway device to use in those patients, an ett or lma. the only level 1 article in this literature review was the study by tartari et al. this randomized control trial (rct) consisted of 400 patients between the ages of 6 months and 12 years.10 the subjects were assigned to either the lma or ett group, and within those groups, it was determined 17volume 2, no. 1 whether or not the child had a uri.10 this study determined that adverse respiratory events were more frequent in children with a uri when compared to children without a uri.10 when an ett was used compared to an lma, children with uris had more adverse respiratory events including laryngospasm, stridor, and excessive coughing. this study advocates the use of lmas over the use of etts in children with uris.10 in the rct performed by wakhloo et al, 40 patients with clear rhinorrhoea and mild cough only were included in the study.4 there was random assignment to 2 different groups, the ett or lma group, based on what airway device was used during their surgical procedures.4 this study found less oxygen desaturation, bronchospasm, and laryngeal stimulation in the lma group as compared to the ett group and an increased risk of postoperative complications when using an ett.4 in the 1998 study performed by tait et al, 82 patients with uris who were eligible to use either a lma or ett in their surgery were included in the study and were randomly assigned to one of these airway devices.6 both the studies by wakhloo et al. and tait et al. found that lmas had more advantages and fewer respiratory related complications than etts.4,6 the advantages of using an lma are decreased incidences of laryngospasm, sore throat, and bronchospasm.4,6 the complications seen with the ett group were coughing, sore throat, laryngospasm, bronchospasms, arterial oxygen desaturation, and breath-holding.4,6 tait and malviya’s 2005 study was a literature review that compared 9 different studies, all of which studied the complications caused by recent or current uris in children undergoing anesthesia.3 when comparing etts and lmas, this study concluded that lmas were associated with fewer adverse respiratory events than etts.3 another literature review written by höhne et al. came to the conclusion that lmas should be used in children with uris undergoing anesthesia.15 höhne et al. recommend, if possible, waiting 4 weeks after a uri for elective aej18 surgeries to allow healing.15 if the surgery cannot be postponed, lmas should be used in those children rather than etts due to the decreased risk of complications.15 the 2001 observational survey of practice study by parnis et al. showed that lmas provide a safe and non-irritating airway to patients with a decreased risk of adverse reactions when compared to etts.8 the 2007 study by homer et al. used data from several prospective observational and interventional studies to come up with their conclusion that lmas have an increased amount of respiratory complications when compared to etts.7 the 2008 retrospective study by flick et al. went through the medical records of 130 pediatric patients who had experienced a laryngospasm during anesthesia.16 this study found that lmas had an increased risk of laryngospasm when compared to etts in children with uris.16 it was not clear what caused the increased risk of laryngospasm with lmas, but it was thought to be the accumulation of secretions in the airway during emergence.16 eikermann and cote wrote an editorial in response to a study by von ungern-sternberg where lmas were used in children with and without current or recent uri symptoms.5,9 the study by von ungern-sternberg found an increased risk of respiratory complications when lmas were used in children who had uris, and a lower risk of adverse respiratory complications in those without recent uris.5 eikermann and cote argued that children with recent uris were more likely to have adverse respiratory reactions with etts rather than with lmas.9 eikermann and cote claimed that, in his experience, lmas were a better choice of airway protection and had a lower risk of complications.9 in reply to the editorial, von ungern-sternberg defended his claim by writing that lmas being used in children with uris have an increased risk of complications.17 both authors agreed that more rcts need to be conducted to provide a clearer position 19volume 2, no. 1 on what airway device has the decreased risk of complications.9,17 both von ungern-sternberg and eikermann and cote agreed that children without uri symptoms in the previous 2 weeks could be safely anesthetized without an increased risk of respiratory complications.5,9 synthesis eight studies have explored whether lmas or etts have an increased risk of adverse reactions when used in children with recent or current uris. an additional 2 editorials discuss the use of lmas and etts in children with recent or current uris. three articles disagree with the statement that lmas have a lower rate of respiratory adverse events than etts in children with uris.7,16,17 the 2 studies provided by homer et al. and flick et al. advocated the use of etts when comparing them to lmas in children with recent or current uris.7,16 the studies by homer et al. and flick et al. did not clearly define the reason for the increased risk of complications in lmas, but the authors thought it was related to the way the airway devices were removed and the secretions found on the vocal cords.7,16 the study by von ungern-sternberg et al. expressed that the authors thought lmas had a higher risk of complications when used in children with uris.17 this original study supported the use of etts in children with current uris but did not compare the complication rates between lmas and etts and was not included in this review for that reason.5 of the 8 articles in which a study was performed, six articles have determined that lmas have a decreased risk of complications when compared to etts when used in children with recent or current uris.3,4,6,8,10,15 lmas have a decreased risk of complications due to the minimal manipulation and irritation to the already hyperreactive airway.3,4,6,8,10,15 lmas sit above the glottic opening so there is less stimulation to the laryngeal opening and vocal cords, limiting the risk of complications.3,4,6,8,10,15 eikermann aej20 and cote, in their editorial, agree from personal experience that lmas have less risk of complications when compared to etts when caring for children with uris.9 limitations of study there were some limitations in the literature. in tait and malviya’s 2005 study, all 9 studies included in the literature review looked at complications caused by recent or current uris in children undergoing anesthesia.3 however, not all 9 studies compared the different airway devices being used in the subjects. future studies an inconsistency with the literature is the amount of time after uri symptoms are resolved that surgery is still considered high risk for the child. some of the literature suggests waiting 2-4 weeks for surgery,3,5,9 when others suggest waiting 4-6 weeks.4,7,8,15 a study should be performed to find the specific time after symptoms are resolved to consider airway manipulation at risk for complications or not. most of the dispute is related to how long the smooth muscle of the airway is hyperreactive. knowing the exact amount of time needed to completely recover from a uri will help anesthesia providers to plan accordingly for their patients. it may be extremely difficult or impossible to determine an exact time since all patients are different. intervention overview according to the literature, lmas should be preferentially used instead of etts in children with recent or current uris undergoing anesthesia.3,4,6,8,9,10,15 lmas have a decreased risk of periand postoperative complications compared to etts in the hyperreactive airway.3,4,6,8,9,10,15 endotracheal tube use in children with hyperreactive airways secondary to uris results in a higher risk of respiratory complications including laryngospasm, bronchospasm, arterial oxygen desaturation, and breath-holding (a complete list is available in table 2).3,4,6,8,9,10,15 21volume 2, no. 1 the upper respiratory infection screening tool© (appendix 1) was created so parents/guardians can fill out a questionnaire regarding the child’s recent health prior to surgery. on the upper respiratory infection screening tool©, common signs and symptoms are listed, and the parent/guardian is to answer whether the patient currently has the symptom, has had the symptom within the past 4 weeks, or has not had the symptom. using this screening tool, anesthesia providers will be able to see quickly if the patient is at a higher risk for complications due to their current or recent uri symptoms. symptoms 1-5 on the screening tool: nasal congestion, sputum production, wheezing, productive cough, and fever greater than 100.4°f (38°c), are symptoms associated with a severe uri.3 two or more of those symptoms puts the child at higher risk for respiratory complications.3,10 the information found on the upper respiratory infection screening tool© can then be used in the decision tree referred to as the management algorithm for children presenting for general anesthesia with upper respiratory infection© (appendix 2). the decision tree was created as a clinical guidance algorithm for anesthesia providers to refer to when deciding the best option for the management of the child presenting for surgery. to use the management algorithm for children presenting for general anesthesia with upper respiratory infection©, the clinician starts at the top with the first question, and each answer will lead the clinician to another question. the result at the end of the tree is a recommendation of the safest way to provide anesthesia care for the child. if the end result recommends proceed with caution, the anesthesia provider needs to ensure the child is adequately hydrated through intravenous fluids, humidification on the patient breathing circuit, and that airway manipulation is only performed when the child is deeply anesthetized.3,6 medications such as sevoflurane, bronchodilators and anticholinergics can be used to help minimize the risk of respiratory complications but are not required to be routinely administered.3,6 aej22 summary the current literature supports the use of lmas over etts when used in children with recent or current uris.3,4,6,8,9,10,15 there is a lower risk of respiratory complications when using a lma in these children.3,4,6,8,9,10,15 anesthesia providers have the responsibility of selecting the right plan of care for each individual patient based on the type of procedure and the patient’s health history. the upper respiratory infection screening tool© and the management algorithm for children presenting for general anesthesia with upper respiratory infection© provide a quick reference for anesthesia providers to look to for guidance when taking care of the pediatric population. author info megan grelson srna megan.grelson@gmail.com acknowledgements: this review was conducted as a student at texas christian university school of nurse anesthesia as part of the doctor of nursing degree requirements. the author appreciates advising/guidance by mark welliver, dnp, crna and hylda nugent, dnp, crna faculty tcu school nurse anesthesia. 23volume 2, no. 1 table 1. signs and symptoms of uris in infants and older childrena infants older children ●» unable to sleep ●» stuffy, runny nose ●» fussiness ●» scratchy, tickly throat ●» congestion in the nose ●» watery eyes ●» sometimes vomiting and diarrhea ●» sneezing ●» fever ●» mild hacking cough ●» congestion ●» sore throat ●» achy muscles and bones ●» headaches ●» low grade fever ●» chills ●» watery discharge from nose and throat ●» mild fatigue a. data derived from children’s hospital boston.1 table 2 – possible anesthetic complications in children with uris ●» laryngospasm4,5,6,7,9,10 ●» stridor3,7,10 ●» secretions3,4,8 ●» bronchospasm3,4,5,6,7,8 ●» hypoxemia5 ●» airway obstruction4,5,8●» breath-holding3,4,6,8 ●» vomiting8 ●» coughing3,4,5,6,7,8,9,10 ●» regurgitation8 ●» atelectasis3,5,6 ●» oxygen desaturation3,5,6,7,8,9 ●» hypotension8 ●» cardiac arrest8 ●» sore throat6 ●» arrhythmia8 ●» death8 aej24 table 3 – the joanna briggs institute levels of evidence14 levels of evidence feasibility f (1-4) appropriateness a (1-4) meaningfulness m (1-4) effectiveness e (1-4) economic evidence 1 metasynthesis of research with unequivocal synthesized findings metasynthesis of research with unequivocal synthesized findings metasynthesis of research with unequivocal synthesized findings meta-analysis (with homogeneity) of experimental studies (eg rct with concealed randomization) or one or more large experimental studies with narrow confidence intervals metasynthesis (with homogeneity) of evaluations of important alternative interventions comparing all clinically relevant outcomes against appropriate cost measurement, and including a clinically sensible sensitivity analysis 2 metasynthesis of research with credible synthesized findings metasynthesis of research with credible synthesized findings metasynthesis of research with credible synthesized findings one or more smaller rcts with wider confidence intervals or quasi-experimental studies (without randomization) evaluations of important alternative interventions comparing all clinically relevant outcomes against appropriate cost measurement, and including a clinically sensible sensitivity analysis 3 a. metasynthesis of text/opinion with credible synthesized findings b. one or more single research studies of high quality a. metasynthesis of text/opinion with credible synthesized findings b. one or more single research studies of high quality a. metasynthesis of text/opinion with credible synthesized findings b. one or more single research studies of high quality a. cohort studies (with control group) b. case-controlled c. observational studies (without control group) evaluations of important alternative interventions comparing a limited number of appropriate cost measurement, without a clinically sensible sensitivity analysis 4 expert opinion expert opinion expert opinion expert opinion, or physiology bench research, or consensus expert opinion, or based on economic theory 25volume 2, no. 1 table 3 – the joanna briggs institute levels of evidence14 levels of evidence feasibility f (1-4) appropriateness a (1-4) meaningfulness m (1-4) effectiveness e (1-4) economic evidence 1 metasynthesis of research with unequivocal synthesized findings metasynthesis of research with unequivocal synthesized findings metasynthesis of research with unequivocal synthesized findings meta-analysis (with homogeneity) of experimental studies (eg rct with concealed randomization) or one or more large experimental studies with narrow confidence intervals metasynthesis (with homogeneity) of evaluations of important alternative interventions comparing all clinically relevant outcomes against appropriate cost measurement, and including a clinically sensible sensitivity analysis 2 metasynthesis of research with credible synthesized findings metasynthesis of research with credible synthesized findings metasynthesis of research with credible synthesized findings one or more smaller rcts with wider confidence intervals or quasi-experimental studies (without randomization) evaluations of important alternative interventions comparing all clinically relevant outcomes against appropriate cost measurement, and including a clinically sensible sensitivity analysis 3 a. metasynthesis of text/opinion with credible synthesized findings b. one or more single research studies of high quality a. metasynthesis of text/opinion with credible synthesized findings b. one or more single research studies of high quality a. metasynthesis of text/opinion with credible synthesized findings b. one or more single research studies of high quality a. cohort studies (with control group) b. case-controlled c. observational studies (without control group) evaluations of important alternative interventions comparing a limited number of appropriate cost measurement, without a clinically sensible sensitivity analysis 4 expert opinion expert opinion expert opinion expert opinion, or physiology bench research, or consensus expert opinion, or based on economic theory aej26 table 4 – levels of evidence and study findings article loe n study findings tartari,10 2000 1 400 rct of lma vs. ett lmas had less adverse respiratory events than etts in children with uris. lmas are preferred over etts in children with uris. tait,6 1998 2 82 rct of lma vs. ett less coughing and oxygen desaturation in lma, no bronchospasm in lma. total respiratory complications significantly greater in ett than lma. lmas lack laryngeal stimulation. “lma seems to offer several advantages over the ett for airway management.” wakhloo,4 2007 2 40 rct of lma vs. ett less oxygen desaturation, no bronchospasm in lma group compared to ett. ett use increases risk of postoperative complications. lmas have decreased amount of laryngeal stimulation and decreased airway complications with uris. tait,3 2005 2 literature review more severe uri symptoms should wait 4 weeks for surgery. ett should be avoided because of increased risk of respiratory complications. lmas are a safe alternative for etts with significantly less complications. 27volume 2, no. 1 article loe n study findings höhne,15 2006 2 literature review lma safe airway device, especially in children with uris. surgery should be delayed 4 weeks if possible, when not possible use lma. homer,7 2007 3 335 logistic regression model. several prospective interventional and observational clinical studies. in general, there was a higher percentage of adverse events with lma as opposed to ett. uri 2-4 weeks prior to surgery had the highest rate of respiratory complications. parnis,8 2001 3 2514 logistic regression model. observational survey of practice patients with etts had highest rate of adverse reactions. lmas or fms had the lowest. lma provides clear, safe airway without irritating patient airway. flick,16 2008 3 130 retrospective study of pediatric patients having experienced a laryngospasm during anesthesia chart reviews identified that lmas have an increased risk of laryngospasm when compared to etts. eikermann,9 2008 4 editorial responding to von ungernsternberg’s article clinical observation stating children without uri within the past few weeks may be safely anesthetized. disagree with von ungern-sternberg’s study that lmas increase the risk of respiratory complications. von ungernsternberg,17 2008 4 in reply to eikermann and cote’s editorial “recent uri is a risk factor for the occurrence of perioperative respiratory complications with the use of an lma.” aej28 appendix 1 upper respiratory infection screening tool© please check any symptoms currently present or present in the last 4 weeks. please answer as accurately as possible. 1. runny nose/nasal congestion 5. fever (greater than 100.4°f) � yes, currently � yes, currently � yes, in last 4 weeks � yes, in last 4 weeks � no � no 2. sputum production 6. malaise (feeling unwell) � yes, currently � yes, currently � yes, in last 4 weeks � yes, in last 4 weeks � no � no 3. wheezing/reactive airway 7. muscular pains � yes, currently � yes, currently � yes, in last 4 weeks � yes, in last 4 weeks � no � no 4. productive cough 8. sneezing � yes, currently � yes, currently � yes, in last 4 weeks � yes, in last 4 weeks � no � no 29volume 2, no. 1 9. hoarse voice 10. sore/scratchy throat � yes, currently � yes, currently � yes, in last 4 weeks � yes, in last 4 weeks � no � no comments: information provided by: relationship: signature: date: aej30 appendix 2 management algorithm for children presenting for general anesthesia with upper respiratory infection© *when proceeding with caution, the following can help to reduce the risk of respiratory complications postoperatively: adequate iv hydration, humidification, bronchodilators, use of sevoflurane, anticholinergics, and ensuring adequate depth of anesthesia prior to airway manipulation.3,6 31volume 2, no. 1 references 1 children’s hospital boston. upper respiratory infection (common cold). children’s hospital boston website. http:// www.childrenshospital.org/az/site1719/mainpages1719p0. html. accessed february 25, 2012. 2 mcgill wa, coveler la, epstein bs. subacute upper respiratory infection in small children. anesth analg. 1979;58(4):331-333. 3 tait ar, malviya s. anesthesia for the child with an upper respiratory tract infection: still a dilemma? anesth analg. 2005;100(1):59-65. 4 wakhloo r, gupta sd, gupta v, ranbhushan. ett vs. lma in pediatric patients with uri: a comparison of adverse respiratory events. internet j of anesthesiol. 2007;14(2) http://find.galegroup.com.ezproxy.tcu.edu/ gtx/infomark.do?&content set=iac-documents&type=r etrieve&tabid=t002&prodid=aone&docid=a177102 029&source=gale&srcprod=aone&usergroupname=txs hracd2573&version=1.0. accessed february 25, 2012. 5 von ungern-sternberg bs, boda k, schwab c, sims c, johnson c, habre w. laryngeal mask airway is associated with an increased incidence of adverse respiratory events in children with recent upper respiratory tract infections. anesthesiol. 2007;107(5):714-719. 6 tait ar, pandit ua, voepel-lewis t, munro hm, malviya s. use of the laryngeal mask airway in children with upper respiratory tract infections: a comparison with endotracheal intubation. anesth analg. 1998;86(4):106-111. 7 homer jr, elwood t, peterson d, rampersad s. risk factors for adverse events in children with colds emerging from anesthesia: a logistic regression. pediatric anesth. 2007;17(2):154-161. 8 parnis sj, barker ds, van der walt jh. clinical predictors of anaesthetic complications in children with respiratory tract infections. paediatric anaesth. 2001;11(1):29-40. aej32 9 eikermann m, cote cj. laryngeal mask airway and children’s risk of perioperative respiratory complications: randomized controlled studies are required to discriminate cause and effect [editorial]. anesth. 2008;108(6):1154. 10 tartari s, fratantonio r, bomben r, paolazzi m, gritti g, alvisi r. maschera laringea vs. tubo orotracheale in anestesia pediatrica nella flogosi felle prime vie aeree [english abstract]. minerva anestesiol. 2000;66(6):439-443. 11 cohen mm, cameron cb. should you cancel the operation when a child has an upper respiratory infection? anesth analg. 1991;72(3):282-288. 12 mosby’s dictionary of medicine, nursing & health professions. 7th ed. st. louis, mo: mosby elsevier; 2006:648. 13 pennant jh, white pf. the laryngeal mask airway. anesth. 1993;79(1):144-163. 14 the joanna briggs institute. levels of evidence fame. the joanna briggs institute website available at: http:// www.joannabriggs.edu.au/levels%20of%20evidence%20 %20fame. updated february 19, 2012. accessed march 3, 2012. 15 höhne c, haack m, machotta a, kaisers u. atemwegsmanagement in der kinderanasthesie [english translation]. anaesthesist. 2006;55(7):809-820. 16 flick rp, wilder rt, pieper sf, et al. risk factors for laryngospasm in children during general anesthesia. pediatric anesth. 2008;18(4):289-296. 17 von ungern-sternberg bs, johnson c, habre w. laryngeal mask airway and children’s risk of perioperative respiratory complications: randomized controlled studies are required to discriminate cause and effect – in reply [editorial]. anesthesiology. 2008:108(6):115. anesthesia for a patient with osteogenesis imperfecta, achondroplastic dwarfism and history of malignant hyperthermia abstract a primary goal for anesthesia providers is to maintain patient safety. this is an even greater concern when taking care of a patient with a complicated medical history. this case report, discusses the care of a 47 year-old female patient who presented to a tertiary care center for an orthopedic procedure. her medical history included osteogenesis imperfecta (oi), achondroplastic dwarfism and suspicion of malignant hyperthermia (mh). there were multiple anesthetic implications to ensure safety for this patient during the perioperative period. oi concerns include bone fragility and potential for multiple fractures even after inoffensive trauma. achondroplastic dwarfism concerns include abnormalities of the upper airway and difficulty with visualizing the glottic opening during direct laryngoscopy.1 malignant hyperthermia is a life threatening disorder, which places the patient at risk for a hypermetabolic reaction if exposed to select anesthetic agents. introduction: patients with osteogenesis imperfect (oi) are placed at high risk during anesthesia for both physiological and anatomical reasons. complications include osteoporosis, joint laxity, and tendon weakness.2 pulmonary compromise may also occur if the patient displays thoracic distortion. these patients have an elevated basal metabolic rate that causes an increase in core body temperature and can mistaken to be mh. no consistent evidence has shown that oi is always associated with mh.2 achondroplastic jaclyn harvey srna dwarfism is the most common form of dwarfism occurring at the rate of 1:30,000 live births. airway abnormalities such as macroglossia, micrognathia, small oral opening and temporomandibular joint immobility can make mask ventilation and intubation challenging for anesthesia providers. the perioperative period can also be complicated with managing restrictive lung disease patterns and cardiovascular abnormalities.1 malignant hyperthermia (mh) is a hypermetabolic disorder that is triggered by anesthetic agents such as succinylcholine, or inhaled anesthetics: halothane, isoflurane, sevoflurane and desflurane. several musculoskeletal disorders are coupled with mh including the patient’s diagnosis of osteogenesis imperfecta. identifying susceptible patients prove difficult because it is a silent disorder until triggered. in addition, 50% of patients who experience an mh crisis had previously received a triggering agent without showing symptoms.3 in this case report a patient presents to a tertiary care hospital with all three of these conditions. naturally, the anesthetic plan for this patient sparked a large amount of discussion for anesthetic management and concern for patient safety. case report a 47 year-old caucasian female presented to a tertiary care center for her 55th surgery. she was 36 inches tall and weighed 24 kg for a bmi of 28.2. the patient was an achondroplastic dwarf with a past medical history of oi leading to her many hospital admissions and surgical history. the patient was wheelchair bound and presented with an adduction deformity of the right hip. the procedural goal was palliative to remove the constant pressure points that caused pain between both knees. the patient also had a suspected history of mh due to parental report of “anesthetic complications” from a previous procedure. medications included cephalexin, alprazolam, and oxycodone. she had no known allergies. the patient was seen in the preoperative holding area by the aej anesthesia team for the preoperative assessment. the assessment focused on her airway, cardiopulmonary and musculoskeletal status. key airway assessment findings included a mallampati class i, oral opening was greater than 4 cm, full dentition intact, mandibular length adequate, thyromental distance of 6 cm, cricothyroid membrane palpable and an atlanto-occipital extension of less than 35 degrees. the patient’s head shape and size was normal and her neck thin. the patient experienced constant pain in her left leg from pressure point contact. she preferred the left lateral position with a pillow between her knees to prevent pressure. her chest was smaller than expected for an adult female and had a kyphoscoliotic shape. lung sounds clear to auscultation and chest x-ray clear throughout lung fields. heart rate assessed as regular with normal s1 and s2 pattern. electrocardiography revealed sinus rhythm with short pr intervals. with the inconclusive malignant hyperthermia history, the anesthesia team proceeded to follow the mh protocol. all mh triggers were removed from the or with a total intravenous anesthetic planned. risks and benefits of the procedure and anesthetic technique were discussed with the patient. she accepted the discussion and signed, giving informed consent. the patient’s number of previous surgical procedures places her at risk for blood loss. blood consent was obtained with two units of packed red blood cells available. preoperative intravenous access was obtained with a 20 gauge iv placed in the right forearm. the patient is a patient status 3. the anesthesia workstation was prepared in accordance with malignant hyperthermia association of the united states (mhaus) recommendations. all mh triggers needed to be eliminated including removing succinylcholine syringes from the induction drug set up and disabling the vaporizers by taping them to the “off” position. the carbon dioxide (co2) absorbent was changed to prevent any fractionated inspired agent from entering the breathing circuit. the anesthesia gas machine (agm) was flushed with 10l/min of oxygen for 20 minutes4 and a new breathing circuit was installed on the agm. please see figure 1. the patient was taken to the or and given 1 milligram of midazolam and 25 micrograms of fentanyl for preoperative sedation and pain management. the patient was lifted to the or table to prevent discomfort and then secured to the table with safety straps. initial position was supine with blankets to support her spine. care was taken to support her arms on padded arm boards bilaterally at less than a 90-degree angle. standard monitors were placed and vital signs (vs) recorded. the patient was denitrogenated with 100% oxygen and induction of anesthesia began with 50 micrograms of fentanyl, 60 milligrams of lidocaine, and 50 milligrams of propofol. once unconscious ventilation was confirmed, the patient received 20 milligrams of rocuronium bromide for paralysis and was intubated with a macintosh 3 blade after cormack i direct visualization of the cords. the patient was intubated with a pediatric cuffed 5.0 endotracheal tube. a propofol infusion at 120 microgram/kg/ min was initiated and a right internal jugular triple lumen catheter was placed. a hotline™ (dublin, oh) fluid warming system was connected to the new central line for fluid management and warming. an upper body forced air warming blanket was applied bair hugger® therapy from arizant inc. the patient was given incremental fentanyl boluses (1 microgram/kilogram) throughout the procedure. as requested by the surgeon, further muscle relaxation was withheld in order to monitor motor responses during the procedure. patient was given zofran 4 milligrams, given to prevent the female predisposition to postoperative nausea and vomiting with general anesthesia 30 minutes prior to emergence. the patient regained four train of four twitches and was reversed with 2 milligrams of neostigmine and 0.4 milligrams of glycopyrrolate. upon emergence the patient awoke, opened her eyes, followed aej commands, and was breathing spontaneously. however, she displayed less than 5 milliliters/kilogram tidal volumes and was transferred to the post anesthesia care unit with an endotracheal tube and on oxygen through a t-piece to protect her airway. postoperative vital signs included a temperature of 37.3 degrees celsius(c), 130 heart rate, blood pressure 120/80, regular respiratory rate of 16 and saturations of 100% on 40% oxygen. she gradually gained strength and was extubated. discussion the pathophysiology of osteogenesis imperfecta is decreased collagen synthesis. ninety percent of individuals have mutations on the type i collagen genes, pro-a1 or proa2. a phenotype often indistinguishable from oi type ii or iii is a mutation of two of the genes responsible for encoding proteins of an enzyme complex lepre1 and cartilage-associated protein causing an autosomal recessive oi.1 patients with osteogenesis imperfect are placed at high risk during anesthesia for both physiological and anatomical concerns. physical manifestations are a large head, small bowed limbs, short neck, blue sclera, otosclerosis, and brittle teeth. complications lend themselves to osteoporosis, joint laxity, and tendon weakness.2 these patients may also have abnormal platelet function leading to an increased risk of bleeding. there is a tendency for early development of atherosclerosis so a cardiovascular assessment that includes evaluation of the mitral and aortic valve function is important. pulmonary compromise may also occur if the patient displays thoracic distortion. these patients have an elevated basal metabolic rate that causes an increase in core body temperature and can mistakenly be thought to be mh. there has been no consistent evidence that oi is always associated with mh.2 achondroplastic dwarfism is a phenotype of disproportionate stature. in 95%of patients the same point mutation occurs on the gene that encodes for fibroblast growth factor receptors, fgfr3.1 the anesthetic management of these patients proves a challenge with abnormalities of their upper airways and difficulty visualizing the glottic opening on direct laryngoscopy. intubation is often challenged by characteristics of a short neck, protruding tongue, as well as enlarged tonsils and adenoids.1 further, these patients may have subglottic stenosis, tracheal and bronchial narrowing. a thoracic dystrophy may be present causing the patient to have reduced lung volumes due to the restrictive disease pattern. cardiac dysfunction may include acquired valvular disease, cor pulmonale and cardiomyopathy. it is advisable to preoperatively obtain a chest x-ray, echocardiogram as well as a physical exam to evaluate the presence and severity of these conditions.1 for the possibility of pulmonary and cardiac complications it is imperative to avoid hypoxemia and hypovolemia. this can exacerbate existing pulmonary hypertension and worsen right ventricular function.1 malignant hyperthermia is a hypermetabolic disorder that is triggered by anesthetic agents such as succinylcholine, or inhaled anesthetics: halothane, isoflurane, sevoflurane and desflurane. several musculoskeletal disorders are associated with mh including osteogenesis imperfecta. exposure to a triggering agent can cause a dramatic increase in skeletal muscle metabolism. the most common first sign of mh is a rapid increase in end tidal carbon dioxide (c02) as metabolism accelerates. other early signs are tachycardia, tachypnea, and increased oxygen consumption, acidosis, muscle rigidity, and rhabdomylosis.5 further symptoms are unstable blood pressure, cyanosis, mottled skin, diaphoresis, dysrhythmias and an increase in patient’s body temperature. temperature increase can be as much as 1-2 degrees c every 5 minutes. the mortality rate of unrecognized mh can be as high as 80%.6 identifying susceptible patients is difficult because it is a silent disorder until triggered. in addition 50% of patients who experience an mh crisis had previously received a triggering agent without showing symptoms.3 mh is a hypermetabolic syndrome that occurs from an abnormal amount of calcium release by the sarcoplasmic reticulum in to the sarcoplasm. aej increased levels of calcium cause elevated oxygen consumption and anaerobic metabolism. the transportation of the calcium is mediated by the ryanodine receptor, isoform 1 (ryr1).3 about 50% of known mh cases are caused by mutations on chromosome 19 at the ryr1 receptor. a small percentage is dihydropyridine (dhp) receptor on chromosome 1.3 the most current dependable method to confirm diagnosis is a muscle biopsy test where the muscle fibers are placed in contact with caffeine and halothane.7 there is 95% reliability for patient susceptibility with a positive muscle contraction.6 summary this case report presents a patient with three rare disorders that each has multiple anesthetic implications. the diagnosis of osteogenesis imperfecta predisposes the patient to brittle bones, joint laxity, and tendon weakness. safety in positioning, movement and transfer of the patient becomes extremely important for a patient with oi. furthermore, these patients often have altered pulmonary or cardiovascular function. achondroplastic dwarfism has additional implications that include airway abnormalities that make mask ventilation and direct laryngoscopy challenging. the presence of the difficult airway cart and availability of immediate surgical personnel are two prudent measures to be taken prior to induction. additionally, this patient reported a possible mh exacerbation during an earlier surgical procedure. this mandates preparation of the anesthesia workstation and clarification amongst anesthesia personnel in order to ensure that no trigger agents reach the patient and that the team is prepared in the event of a hypermetabolic event. this case illustrates the importance of a thorough preoperative assessment, development of a comprehensive plan involving both anesthesia and surgical teams and the need for constant vigilance. maintaining an open line of communication throughout the procedure is imperative in order to reach the ultimate goal of patient safety. references 1. davis pj, cladis fp & motoyama ek. smith’s anesthesia for infants and children. 8th ed. philadelphia: elsevier mosby; 2011. 2. barash pgc, bruce f, stoelting rk. clinical anesthesia. 5th ed. philadelphia: lipincott williams & wilkins; 2006. 3. litman rs, rosenberg h. malignant hyperthermia: update on susceptibility testing. jama : the journal of the american medical association. [research support, non-u.s. gov’t]. 2005 jun 15;293(23):2918-24. 4. malignant hyperthermia association of the united states. 2011; available from: http://www.mhaus.org/. accessed june1, 2012 5. rosenberg h, davis m, james d, pollock n, stowell k. malignant hyperthermia. orphanet journal of rare diseases. [review]. 2007;2:21. 6. guideline statement for malignant hyperthermia in the perioperative environment. association of surgical technologies [serial on the internet]. 2005; (october): available from: http://www.ast.org/pdf/standards_of_practice/ guideline_malignant_hyperthermia.pdf. accessed january 22, 2012 7. rosenberg h, antognini jf, muldoon s. testing for malignant hyperthermia. anesthesiology. [research support, non-u.s. gov’t]. 2002 jan;96(1):232-7. acknowledgements acknowledgment is given to john m. o’donnell drph, rn, crna, msn as mentor and critiquing the case study. aej figure 1 photo by jaclyn harvey srna graphic courtesy of: children’s hospital of university of pittsburgh medical center volume 8no. 2 2020 educated hand publishing llc “the science behind the art” volume 8 no. 2 2020 anesthesia ejournal online issn 2333-2611 page 6 prevention of opioid-induced hyperalgesia following remifentanil infusion: a case report lauren gray, bsn, rn affiliation: texas christian university funding/conflict of interest disclosure: none keywords: opioid-induced hyperalgesia; postoperative pain; remifentanil; total intravenous anesthesia abstract remifentanil, a potent mu-opioid agonist, is useful in anesthesia because of its rapid onset and short duration of action. however, the same traits that make remifentanil useful can also lead to increased pain sensation when remifentanil is discontinued. nociceptive sensitization following opioids is termed opioid-induced hyperalgesia (oih). proposed preventive treatments for remifentanil-induced oih run the spectrum of cost and feasibility. this case report will discuss the use of and rationale for readily available techniques aimed at preventing oih. these techniques include intravenous ketamine, inhaled nitrous oxide, oral pregabalin, and gradual cessation of remifentanil infusion. introduction increases in postoperative pain occur after intraoperative remifentanil infusions. a 2014 systematic review and meta-analysis including 1494 patients found an association between high doses of intraoperative remifentanil and small but significant increases in postoperative pain intensity.1 pain in the postoperative period can lead to activation of the stress response, activation of the sympathetic nervous system, and activation of harmful spinal reflex arcs. these processes caused by poorly controlled postoperative pain contribute to increased morbidity and mortality resulting from hypercoagulability, immunosuppression, poor wound healing, myocardial ischemia, delayed return of gastrointestinal function, and decreased pulmonary function.2 therefore, if remifentanil is part of the anesthetic plan, preventive analgesia becomes an important component of that plan. the purpose of this case report was to evaluate methods for preventing opioid-induced hyperalgesia (oih) after remifentanil infusion. aej educated hand publishing llc “the science behind the art” volume 8 no. 2 2020 anesthesia ejournal online issn 2333-2611 page 7 case summary a 70-year-old, 99-kg, 172-cm man presented with degenerative disc disease and was scheduled for a laminectomy with fusion from lumbar segment 2 to 5. the patient’s medical history included coronary artery disease, hypertension, high cholesterol, type 2 diabetes mellitus, neuropathy, obstructive sleep apnea, prostate cancer, and low back pain. his surgical history included cardiac stenting, prostate removal, bladder stone removal, and right shoulder arthroscopy with rotator cuff repair. the patient denied having any previous anesthesia complications. his current medication treatment included metformin, metoprolol, potassium chloride, and nitroglycerine. the patient was noted to have medication allergy to levofloxacin (rash, hives). laboratory results and electrocardiography and chest radiography findings were unremarkable. no other diagnostic testing was ordered. during the preanesthetic assessment, the patient stated he was not having current back pain. he described having a history of intermittent back pain usually coinciding with activity ranging from 2 to 7 on a 10-cm visual analogue scale (vas). midazolam 2 mg was administered intravenously after the standard preprocedural time out. the patient was taken to the operating room. intraoperative monitors included pulse oximetry, electrocardiography, noninvasive blood pressure monitoring, carbon dioxide capnography, esophageal temperature, bispectral index (coviden ltd, dublin, ireland), and somatosensory evoked potentials. preinduction vital signs were as follows: pulse, 53; blood pressure, 149/65 mm hg; oxygen saturation, 97%; respirations, 16; and temperature, 36.3°c. oxygen was administered via face mask at 10 l/min. after 5 minutes of pre-oxygenation, general anesthesia was induced with 100 mg lidocaine, 100 mcg fentanyl, 180 mg propofol, and 100 mg succinylcholine intravenously. direct laryngoscopy with a macintosh #3 blade was performed and the airway was secured with a 7.5 endotracheal tube. correct endotracheal tube placement was confirmed with visible chest rise, capnography, and auscultation of bilateral breath sounds. after induction of anesthesia, the patient was transferred to a prone surgical bed. total intravenous anesthesia was utilized because of the need to monitor somatosensory evoked potentials. anesthesia was maintained by using an intravenous infusion of 100 mcg/kg/min propofol and 0.5 mcg/kg/min remifentanil. the propofol infusion was titrated to maintain a bispectral index between 40 and 60. the patient showed no physiologic indicators of nociception during the procedure, and the remifentanil infusion was not titrated. physiologic indicators of pain were considered increases in heart rate or blood pressure above baseline. medical air 1 l/min and oxygen 1 l/min were used together for gas flow. prophylactic antibiotics included 1.5 g cefuroxime and 1 g vancomycin administered intravenously. the propofol infusion was discontinued at the time of surgical wound closure. hydromorphone 0.4 mg was administered intravenously. the remifentanil infusion was discontinued. to stimulate spontaneous respirations, ventilation settings were adjusted to a tidal volume of 450 and a rate of 8 breaths per minute to allow paco2 to rise. spontaneous respirations with adequate tidal volumes were achieved within 5 minutes. the patient was rotated to a supine position. the endotracheal tube was removed, and the airway remained patent. the patient was transported to the post-anesthesia care unit with oxygen at 8 l/ min via facemask. postoperative vital signs were as follows: pulse, 87; blood pressure, 117/71 mm hg; respiratory rate, 12; spo2, 100%; and temperature, 36.2°c. hydromorphone 1.5 mg was administered intravenously at 5-minute intervals in 0.5-mg doses in the post-anesthesia care unit. the patient was admitted to the hospital for continued evaluation. during a follow-up visit 24 hours postoperatively, the patient stated that his pain was well controlled except for a 30-minute interval when his pain was 7 on a 10-cm vas. this interval of increased pain intensity occurred 3 hours postoperatively. no other adverse outcomes were noted. discussion the use of remifentanil infusions during general anesthesia has been associated with hyperalgesia in the postoperative period. in the first systematic review and meta-analysis concerning oih in surgical patients, treatment with high doses of intraoperative remifentanil was associated with higher pain intensity during the first 24 hours after surgery.1 in the 27 studies included in the systematic review, a high dose of remifentanil was typically considered an infusion of 0.3 mcg/kg/min. some of the studies used higher or lower doses, but in each study a comparison was made between an opioid, predominately remifentanil, and either a lower dose of the same opioid or a placebo. the study included oropharyngeal, neurosurgical, cardiothoracic, and abdominal surgeries. the study acknowledged that a possible cause of the increase in pain intensity was an acute opioid tolerance after remifentanil infusion, because patients experiencing oih also consumed more morphine in the first 24 hours after surgery.1 another possible explanation is that remifentanil causes longterm potentiation of c-fibers through activation of mu-opioid receptors and n-methyl-d-aspartate (nmda) receptors.3 although the exact mechanism is still being determined, anesthetic management of patients receiving remifentanil should include techniques that will lower the incidence of oih in the postoperative period. ketamine infusion it is postulated that oih is due to central sensitization through activation of nmda receptors.3 in support of this hypothesis, the nmda receptor antagonist ketamine has been shown to decrease postoperative pain intensity and morphine requirements in patients receiving remifentanil infusion during general anesthesia.4,5 hong and colleagues used a 0.3-mg/kg intravenous bolus of ketamine during induction followed by a 3-mcg/kg/min ketamine infusion during surgery to effectively prevent oih and decrease the total amount of opioids required in those undergoing general anesthesia utilizing sevoflurane and remifentanil.4 a separate study set out to determine the effective dose of ketamine to prevent oih. for a ketamine bolus delivered intravenously before skin incision, the ed50 was determined to be 0.24 mg/kg and the ed95 was determined to be 0.33 mg/kg.5 if used in this case, ketamine could potentially have lessened postoperative pain intensity and opioid consumption. pregabalin in 93 patients undergoing general anesthesia for laparoscopic urologic surgery where a remifentanil infusion was utilized, a single dose of 300 mg pregabalin orally before surgery was found to increase the time from the end of surgery to the first analgesic requirement, to decrease the amount of pain medication via patient-controlled analgesia pump during the first 24 hours postoperatively, and to decrease postoperative pain intensity for 24 hours.6 the study confirmed the existence of oih by first comparing 2 groups who did not receive pregabalin. patients receiving 0.3 mcg/kg/min remifentanil had increased pain intensity for 24 hours following surgery compared with patients receiving 0.05 mcg/kg/min remifentanil. furthermore, by adding a third group who received the high dose of remifentanil and pregabalin, the results of this study showed that a single dose of pregabalin could help to prevent oih resulting from remifentanil infusion.6 the pregabalin dose was given 1 hour before anesthesia. the likely mechanism is prevention of central pain sensitization and increased spinal nerve excitability as opposed to direct analgesic activity.6 the patient in this case report did not indicate any history of gastroesophageal reflux during the preoperative assessment, making this oral drug a viable option for prevention of oih. nitrous oxide the use of nitrous oxide, an nmda antagonist, has been associated with a significant reduction in postoperative oih in those receiving total intravenous anesthesia using propofol and remifentanil. the study showed that administering nitrous oxide at 70% decreased postoperative oih for 12 to 18 hours when compared with an anesthetic using 100% oxygen.7 it is of note that postoperative pain intensity and opioid consumption were similar among the 2 groups and that the decrease in oih was measured by using mechanical pain thresholds on the arm.7 therefore, nitrous oxide is an option for preventing oih but may be a less potent preventive. furthermore, in the present case it would not have been a viable alternative because total intravenous anesthesia was used for ideal neuromonitoring conditions. gradual withdrawal of remifentanil infusion avoidance of sudden cessation of a remifentanil drip has been associated with prevention of oih.8,9 rodent studies have demonstrated that when an intravenous infusion of 7.5 mcg/ kg/min remifentanil was gradually decreased over 30 minutes, the long-term potentiation of c-fibers that accompanies oih was prevented.10 a 2014 study in patients undergoing spinal surgery found that abrupt cessation of a remifentanil drip was associated with a higher incidence of oih compared with slow cessation over 90 minutes after surgery.9 these results indicate that an abbreviated but still pronounced withdrawal beginning at the start of surgical wound closure when nociception is typically lower could prevent oih. this method may be effective but not practical in fast-paced anesthesia settings. another alternative in longer procedures would be a weaning of a remifentanil infusion toward the end of surgery while introducing longer-acting opioids to assist in prevention of oih. this plan would incorporate remifentanil dosing guidelines which state that adequate postoperative analgesia should be achieved before discontinuation of remifentanil infusion.11 summary the development of oih is a concern in patients receiving a remifentanil infusion as a component of a general anesthetic.1 anesthesia professionals should be aware of this risk. while this case report did not involve a patient with excessive hyperalgesia postoperatively, there was a 30-minute period during which the patient experienced an increased pain intensity. when remifentanil infusions are used, it may be prudent to include medications that could prevent oih. pregabalin 300 mg given orally 1 hour before surgery, 0.3 mg/kg ketamine administered as an intravenous bolus with or without a 3-mcg/kg/min infusion, and 70% inhaled nitrous oxide are viable options for prevention of oih. after the anesthesia professional weighs the risk-benefit ratio, these medications may be incorporated. if pharmacologic interventions are contraindicated, a gradual withdrawal of the remifentanil infusion may aid in the prevention of oih. educated hand publishing llc “the science behind the art” volume 8 no. 2 2020 anesthesia ejournal online issn 2333-2611 page 8 references 1. fletcher d, martinez v. opioid-induced hyperalgesia in patients after surgery: a systematic review and a meta-analysis. br j anaesth. 2014;112(6):991-1004. doi:10.1093/bja/aeu137. 2. hurley rw, murphey jd, wu cl. acute postoperative pain. in: miller rd, ed. miller’s anesthesia. 8th ed. philadelphia: elsevier; 2015:2975-2997. 3. heinl c, drdla-schutting r, xanthos dn, sandkühler j. distinct mechanisms underlying pronociceptive effects of opioids. j neurosci. 2011;31(46):16748-56. doi:10.1523/jneurosci.3491-11.2011. 4. hong bh, lee wy, kim yh, yoon sh, lee wh. effects of intraoperative low dose ketamine on remifentanil induced hyperalgesia in gynecologic surgery with sevoflurane anesthesia. korean j anesthesiol. 2011;61(3):238-43. doi:10.4097/ kjae.2011.61.3.238. 5. hang lh, shao dh, gu yp, colvin la, fallon mt. the ed50 and ed95 of ketamine for prevention of postoperative hyperalgesia after remifentanil-based anaesthesia in patients undergoing laparoscopic cholecystectomy. swiss med wkly. 2011;141. doi:10.4414/smw.2011.13195. 6. lee c, lee hw, kim jn. effect of oral pregabalin on opioid-induced hyperalgesia in patients undergoing laparo-endoscopic single-site urologic surgery. korean j anesthesiol. 2013;64(1):19-24. doi:10.4097/kjae.2013.64.1.19.7. 7. echevarria g, elgueta f, fierro c, et al. nitrous oxide (n2o) reduces postoperative opioid-induced hyperalgesia after remifentanilpropofol anaesthesia in humans. br j anaesth. 2011;107(6):959-65. doi:10.1093/bja/aer323.8. 8. 8comelon m, raeder j, stubhaug a, nielsen cs, draegni t, lenz h. gradual withdrawal of remifentanil infusion may prevent opioid-induced hyperalgesia. br j anaesth. 2016;116(4):524-30. doi:10.1093/bja/aev547. 9. alves s, carvalho c, mesquita m, dias j, carvalho m, mendes d. remifentanil associated static hyperalgesia may be attenuated by the avoidance of sudden infusion cessation. eur j anaesthesiol. 2014;31:141-142. 10. drdla r, gassner m, gingl e, sandkühler j. induction of synaptic long-term potentiation after opioid withdrawal. science. 2009;325(5937):207-10. doi:10.1126/science.1171759. 11. dosing. ultiva (remifentanil hcl) web site. http://www.ultiva.com/how-to-use-ultiva/dosing. accessed feb 22, 2018. about the author lauren gray is completing the final year of a doctor of nursing practice at texas christian university. gray graduated summa cum laude from the university of texas health science center in san antonio with a bachelor of science in nursing. before beginning her doctoral education, gray was an intensive care nurse at methodist hospital in san antonio where she actively participated in the largest heart failure and heart transplantation program in south texas. her current professional interests include pharmacology, cardiovascular physiology, regional anesthesia, and infection prevention. educated hand publishing llc “the science behind the art” volume 8 no. 2 2020 anesthesia ejournal online issn 2333-2611 page 9 volume 5 no. 1 2017 educated hand publishing llc “the science behind the art” volume 5 no. 1 2017 anesthesia ejournal online issn 2333-2611 page 1 environmental impact of inhaled anesthetics: a literature review jake margulies, msn, crna dirk bahoravitch, msn, crna shawn collins, phd, dnp, crna ian hewer, msn, crna affiliation: western carolina university funding/conflict of interest disclosure: none keywords: environment, inhaled anesthetics, greenhouse gases introduction certified registered nurse anesthetists administer nearly 43 million anesthetics in the united states each year.1 many patients receive volatile anesthetics to induce and maintain a satisfactory depth of anesthesia. volatile anesthetics are also greenhouse gases (ghgs).2 approximately 500,000 gallons of anesthetic ghgs are vented into the environment annually in the united states alone, an impact that translates to the ghg emissions of approximately 1 million vehicles annually.2 ghgs serve to trap the sun’s radiative energy in the earth’s atmosphere, contributing to global warming. these wasted anesthetic gases, which currently are not commonly recycled or reused, total nearly $1 billion in expenses bared by anesthesia providers and passed on to patients and 8% of total carbon dioxide (co2) emissions3,4 annually in the united states alone. current research demonstrates that increasing air pollution causes significant increases in cardiac disease, pulmonary disease, and even death—including 16% of lung cancer, 11% of chronic obstructive pulmonary disease, and 20% of ischemic heart disease and stroke deaths.5 an estimated 150,000 deaths per year (0.3% of all annual deaths) are said to be related to climate by the world health organization (who), and this number is expected to increase.6 the climate-associated health risks identified by the who include food and water insecurity, increased transmission of infection, heat stress, more frequent and extreme weather events, threats to shelter and security, and population migration.7 because of the medical necessity of volatile anesthetic gases, no prior regulations on emissions have been sought.8 however, with the increased number of individuals undergoing surgery and anesthesia and the development of newer anesthetic agents, the environmental impacts of these anesthetics should be evaluated. the purpose of this literature review was to identify, assimilate, and summarize the known impact of volatile anesthetics on the earth’s environment and the global population; to review ways to reduce and eliminate these impacts; and to provide evidence supporting the need for changes in current practice and future practice development that can reduce the environmental impact and side effects related to volatile anesthetic use. abstract current research demonstrates that increasing air pollution causes significant increases in cardiac disease, pulmonary disease, and even death. the known consequences of increasing greenhouse gases parallel those of air pollution and include higher rates of cardiovascular disease, asthma, and infectious disease. this literature review aimed to identify, assimilate, and summarize the known impacts of volatile anesthetics on the earth’s environment. we present methods that are being used to reduce or eliminate these effects. we also aimed to summarize any known health effects on humans related to volatile anesthetic use and to review ways to reduce and eliminate these impacts. it is our hope that this review will provide evidence that leads to a change in current practice and future practice development that reduces the environmental impact and side effects related to volatile anesthetic use. aej anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 1 2017 page 2 history and review of the literature this systematic review of the literature began with a thorough search for articles relevant to this topic. the databases searched included ebscohost (ebsco, ipswich, ma), google scholar (google inc, mountain view, ca), and cochrane review (the cochrane collaboration, london, united kingdom). search terms, used alone and in combination, included environment, environmental, pollution, climate, global warming, anesthesia, anesthetics, inhalational anesthetics, volatile anesthetics, implications, health, management, waste, impact, life-cycle, and scavenging. the literature search criteria were limited to pertinent english-language articles from the last 20 years. in total, 16 articles were located. fourteen articles were included for review as 2 of the articles were not primary sources. anderson et al2 provide an excellent chemical analysis of volatile anesthetics and describe their potential as both ghgs and ozone-destroying agents. according to these authors, all volatile anesthetics are ghgs, meaning that they have a significant atmospheric lifetime and possess infrared absorption bands that overlap the outgoing radiation from the earth’s lower atmosphere. ghgs trap the outgoing radiation and cause the earth’s temperature to rise. in addition to trapping radiation, some but not all ghgs also actively deplete the ozone. ozone is an inorganic molecule that is most heavily concentrated in the stratosphere and that prevents ultraviolet radiation from reaching the earth’s surface.9 the overall effect of ghgs and ozone-depleting gases is to increase the amount of the sun’s radiation that enters and is trapped within the earth’s atmosphere, which is believed to cause climate change. isoflurane, compared with sevoflurane and desflurane, is the only volatile anesthetic capable of destroying stratospheric ozone, attributable to the catalyzation that its chlorine ion provides.2 the global warming potential (gwp) of volatile anesthetics depends on the timeframe in which they are considered. some agents may be strong ghgs and contribute strongly to ozone depletion, but their environmental half-life may be very short. another agent may not be destructive to the ozone or as potent a ghg, but may stay in the atmosphere for hundreds of years. when assessing gwp, time frames of 20, 50, and 100 years are used. the 100-year time frame is the most widely used. desflurane may be the most environmentally harmful, because it is used and released into the atmosphere in higher quantities. in addition, desflurane has a high gwp of over 100 years. anderson et al2 report that, ultimately, halogenated organic compounds are responsible for 10% to 15% of the radiation forces of climate change by ghgs. nitrogen oxides, including nitrous oxide (n2o) and nitric oxide, are known ozone-depleting substances.10 there has been great success in reducing ozone-depleting emissions of chlorofluorocarbons, chlorine, and bromine gases through the montreal protocol, an international treaty aimed at protecting the ozone layer by phasing out substances that cause ozone destruction. however, this has resulted in an increase in the contribution of n2o to gwp; n2o is now second only to methane. although the primary anthropogenic source of n2o emissions is fertilizer use, anesthesia providers should still be cognizant of the ozone-depleting capabilities of n2o use.10 the atmospheric lifetime of n2o emissions, at 114 years, is much longer than that of the other inhaled anesthetics, which range from 1 to 14 years.8 in addition, n2o is usually used in greater volumes, at concentrations of 40% to 60%, in an anesthetic, thus increasing the impact over other anesthetics used in lower volumes at concentrations between 1% and 6%.8 in 2010 infrared spectrometry was used to estimate the gwp of inhaled anesthetics.11 looking at the 20-year gwp, desflurane and n2o were reported to have significantly greater impacts on global warming than isoflurane or sevoflurane. furthermore, n2o was reported to contribute to the destruction of the ozone. these authors concluded that to minimize increases to global warming, providers should avoid using n2o, use as low fresh gas flows (fgfs) as possible, and use either isoflurane or sevoflurane.11 despite the controversy, the fact that desflurane and n2o have significantly greater impacts than other anesthetics holds true. using desflurane for 1 hour at 1 minimum alveolar concentration (the alveolar concentration of anesthetic needed to prevent motor response in 50% of subjects in response to surgical stimulation) equates to the ghg emissions of driving 200 to 400 miles in the average automobile.8 the ghg emissions of sevoflurane and isoflurane are significantly lower, equaling the ghg emissions of driving 8 to 18 miles.8 sherman et al12 performed a cradle-to-grave analysis of volatile anesthetics, meaning they looked at the total environmental footprint of the volatile anesthetics. the data incorporated production, transport, use, and waste disposal as they relate to contribution to ghgs. overall, the lifecycle phases of the volatile anesthetics contribute a relatively insignificant amount to their overall ghg emission compared to agent release into the atmosphere during use. the authors concluded that desflurane and n2o contribute most as ghgs, while isoflurane and sevoflurane contribute much less, especially at low flows. they also reference several technologies in development with the potential to eliminate waste gases through capturing and recycling. these technologies include the dynamic gas scavenging system (anesthetic gas reclamation llc, nashville, tn) and the deltasorb anesthetic collection service (blue-zone technologies ltd, toronto, canada). berry et al13 described 4 operating rooms that had been equipped with reclaiming waste anesthetic gas (wag) scavenging systems. easy installation and 99% efficiency in eliminating wag was reported. the authors concluded that recycled product may decrease cost and increase the availability of modern volatile anesthetics worldwide. while several authors have postulated that wag could be reprocessed and reused using a scavenging system, this was the only trial of this technology that could be found in the literature. jänchen et al14 performed trails of silica zeolite absorbers and found them useful in collecting desflurane from the waste gas outlet during anesthesia. these authors state that the use of charcoal absorbers is partially effective at filtering desflurane from wag, therefore reducing the environmental waste of this gas. zeolite consists of crystalline microporous aluminosilicates. zeolite is much more effective in filtering and desorption of anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 1 2017 page 3 desflurane for collection. in the clinical trial, 62% to 86% of used desflurane could be collected with the use of zeolite filters.14 this technology holds the potential to eliminate the environmental impact of desflurane. with purification, this recovered desflurane also holds significant economic savings potential. through the use of the gasman computer tool (med man simulations, chestnut hill, ma), feldman15 was able to simulate the various phases of anesthesia, including induction, maintenance, and emergence, and the amount of volatile anesthetic used during each phase under certain fgfs and volatile anesthetics. he found that by reducing flows as safely as conditions allow, it may be possible to prevent the release of millions of liters of volatile anesthetics into the atmosphere over the course of a provider’s lifetime. key points included turning off flows while intubating, titrating flows to patient oxygen needs to reduce use of agents, keeping flows low during emergence, and adjusting the vaporizer to prevent gases from venting to the atmosphere. compared with those of the volatile anesthetics, the ghg effects of propofol are minimal. propofol is, however, not a benign drug in reference to its environmental effects. mankes16 specifically looked at propofol wastage and its environmental impacts. he found that propofol does not degrade in nature, accumulates in body fat, and is ultimately toxic to aquatic life. he recommended that propofol wastage—and in turn environmental impact—could be reduced by only stocking 20-ml vials. discussion environmental air pollution and climate change pose threats to health, food and water insecurity, increases in infectious disease, extreme weather, and population migration.17 health care providers should be cognizant of the environmental impact of the care they provide. anesthesia providers must own the entirety of their practice, realizing that the impact does not end when the patient leaves the operating room. aside from the fact that inhaled anesthetics have a negative effect on the ozone layer and global warming, if we know that inhaled anesthetics have enough of a negative health impact that we must restrict exposure to these gases in the operating room, why do we simply vent them into our surrounding environment? given the findings of this literature review, it appears that all volatile anesthetics contribute, to some degree, to global warming. wag recycling systems have the potential to decrease these effects. recycling has become an everyday part of our lives outside the operating room. with the development of these new technologies, recycling can now take place in the operating room as well. as such, we should advocate for the use of these technologies in everyday practice. recycling of wag holds the potential to eliminate the direct impact these agents have on global warming and the ozone layer as well as the potential to reduce the impact of their manufacture and transportation.12 technologies for the collection and recycling of anesthetic waste gases include the dynamic gas scavenging system developed by anesthetic gas reclamation and implemented and tested with the vanderbilt university medical center.18 with this system, 99% of anesthetic gases are collected and reused. because the vacuum only runs 10% of the time, the system also produces energy cost savings. the deltasorb canister developed by bluezone technologies filters self-sterilizing anesthetics that can then be sold back to pharmaceutical companies at costs less than the costs of producing the original drug.18 challenges to the reuse of wag include transmission of infectious disease, degradation of the quality of the drugs, costs, and existing market pressures from anesthetic gas manufacturers.13 until these systems can be implemented on a widespread basis, anesthesia providers must be vigilant in reducing the environmental impact and costs of anesthesia. employing techniques to limit hazards include low-flow anesthetics, choice of anesthetic agents, and proper maintenance of equipment. high fgfs are only necessary when rapid changes in anesthetic depth are necessary (eg, induction and emergence). maintenance, often the longest phase of anesthesia, is the ideal time to use low fgfs and to minimize anesthetic waste gases. using an estimated oxygen consumption of 5 ml/kg/min for a 70-kg patient, only 350 (ml/min) oxygen, plus additional oxygen to compensate for sampling and circuit leaks,8 is required to deliver a volatile agent and maintain patient oxygenation. to safely implement low fgfs, close monitoring of inspired and expired oxygen concentrations is essential. decreasing inspired concentrations of oxygen indicates underestimation of oxygen metabolism and flows should be increased accordingly.8 this review was limited by the relatively small body of literature on this topic. to further these findings, more research and development is required. while there is more literature pertaining to the science of global warming and climate change, this remains a highly debated and politicized topic. perhaps a focus on the financial benefit of wag recycling would be the most effective avenue for gaining support for these technologies. one alternative to the use of volatile anesthetics is the use of total intravenous anesthesia. propofol and other intravenous anesthetics are not without environmental impact. summary in 2009, costello et al declared, “climate change is the biggest global health threat of the 21st century.”19 given the environmental impacts of the inhaled anesthetics and the development of new technologies for wag reclamation, this technology should be widely implemented when clinically available. given the interplay between environment and health, changes in practice that reduce or eliminate wag are worthy of consideration by health care providers. the potential cost savings associated with reclaimed reusable anesthetic should be investigated further. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 1 2017 page 4 references 1. certified registered nurse anesthetists fact sheet. american association of nurse anesthetists website. http://www.aana.com/ ceandeducation/becomeacrna/pages/nurse-anesthetists-at-a-glance.aspx. last updated august 26, 2016. accessed january 3, 2016. 2. andersen mps, nielsen oj, wallington tj, karpichev b, sander sp. assessing the impact on global climate from general anesthetic gases. anesth analg. 2012;114(5):1081-1085. http://dx.doi.org/10.1213/ane.0b013e31824d6150. 3. chung jw, meltzer d. estimate of the carbon footprint of the us health care sector. jama. 2009;302(18):1970-1972. http:// dx.doi.org/10.1001/jama.2009.1610. 4. mcgain f, story d, kayak e, kashima y, mcalister s. workplace sustainability: the “cradle to grave” view of what we do. anesth analg. 2012;114(5):1134-1139. http://dx.doi.org/10.1213/ane.0b013e31824ddfef. 5. arranz mc, munoz moreno mf, medina aa, capitan ma, vaquer fc, gomez aa. health impact assessment of air pollution in valladolid, spain [published online october 17, 2014]. bmj open. 2014;10. http://dx.doi.org/10.1136/ bmjopen-2014-005999. 6. protecting health from climate change. world health organization. http://whqlibdoc.who.int/ publications/2009/9789241598880_eng.pdf. published 2009. accessed january 3, 2016. 7. climate change and human health. world health organization website. http://www.who.int/globalchange/en/. published 2016. accessed january 3, 2016. 8. huncke tk, ryan s, hopf hw, et al. greening the operating room: reduce, reuse, recycle, and redesign. schaumburg, il: american society of anesthesiologists; 2012. 9. liftin k. ozone discourses: science and politics in global environmental cooperation. new york, ny: columbia university press; 1994. 10. ravishankara ar, daniel js, portmann rw. nitrous oxide: the dominant ozone-depleting substance emitted in the 21st century. science. 2009;326(5949):123-125. http://dx.doi.org/10.1126/science.1176985. 11. ryan s, nielsen c. global warming potential of inhaled anesthetics: application to clinical use. anesth analg. 2010;111:92-98. 12. sherman j, le c, lamers v, eckelman m. life cycle greenhouse gas emissions of anesthetic drugs. anesth analg. 2012;114(5):1086-1090. http://dx.doi.org/10.1213/ane.0b013e31824f6940. 13. berry j, barwise j, lancaster l. reclaiming waste anesthetic gas: initial clinical trials. eur j anaesthesiol. 2007;24(suppl 39):32. http://dx.doi.org/10.1097/00003643-200706001-00117. 14. jänchen j, brückner jb, stach h. adsorption of desflurane from the scavenging system during high-flow and minimal-flow aneasthesia by zeolites. eur j anaesthesiol. 1998;15(3):324-329. http://dx.doi.org/10.1097/00003643-199805000-00014. 15. feldman j. managing fresh gas flow to reduce environmental contamination. anesth analg. 2012;114(5):1093-1101. http:// dx.doi.org/10.1213/ane.0b013e31824eee0d. 16. mankes r. propofol wastage in anesthesia. anesth analg. 2012;114(5):1091-1092. http://dx.doi.org/10.1213/ ane.0b013e31824ea491. 17. ryan s, sherman j. sustainable anesthesia. anesth analg. 2012;114(5):921-923. http://dx.doi.org/10.1213/ ane.0b013e31824fcea6. 18. yasny js, white j. environmental implications of anesthetic gases. anesth prog. 2012;59(4):154-158. http://dx.doi. org/10.2344/0003-3006-59.4.154. 19. costello a, abbas m, allen a, et al. managing the health effects of climate change. lancet. 2009;373(9676):1693-1733. http:// dx.doi.org/10.1016/s0140-6736(09)60935-1. http://www.aana.com/ceandeducation/becomeacrna/pages/nurse-anesthetists-at-a-glance.aspx http://www.aana.com/ceandeducation/becomeacrna/pages/nurse-anesthetists-at-a-glance.aspx http://dx.doi.org/10.1213/ane.0b013e31824d6150 http://dx.doi.org/10.1001/jama.2009.1610 http://dx.doi.org/10.1001/jama.2009.1610 http://dx.doi.org/10.1213/ane.0b013e31824ddfef http://dx.doi.org/10.1136/bmjopen-2014-005999 http://dx.doi.org/10.1136/bmjopen-2014-005999 http://whqlibdoc.who.int/publications/2009/9789241598880_eng.pdf http://whqlibdoc.who.int/publications/2009/9789241598880_eng.pdf http://www.who.int/globalchange/en/ http://dx.doi.org/10.1126/science.1176985 http://dx.doi.org/10.1213/ane.0b013e31824f6940 http://dx.doi.org/10.1097/00003643-200706001-00117 http://dx.doi.org/10.1097/00003643-199805000-00014 http://dx.doi.org/10.1213/ane.0b013e31824eee0d http://dx.doi.org/10.1213/ane.0b013e31824eee0d http://dx.doi.org/10.1213/ane.0b013e31824ea491 http://dx.doi.org/10.1213/ane.0b013e31824ea491 http://dx.doi.org/10.1213/ane.0b013e31824fcea6 http://dx.doi.org/10.1213/ane.0b013e31824fcea6 http://dx.doi.org/10.2344/0003-3006-59.4.154 http://dx.doi.org/10.2344/0003-3006-59.4.154 http://dx.doi.org/10.1016/s0140-6736(09)60935-1 http://dx.doi.org/10.1016/s0140-6736(09)60935-1 anesthesia ejournal volume 4 issue 1 2016 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 page 6 the effectiveness of an anesthesia handoff tool: an electronic health record application to enhance patient safety karen gillikin, msn, msna dnp, crna nathaniel apatov, msn, mhs, phd, crna affiliation: dr gillikin is associate director of old dominion university school of nursing, nurse anesthesia program, norfolk, va dr apatov is is the director at old dominion university school of nursing, nurse anesthesia program, norfolk, va funding/conflict of interest disclosure: none introduction patient care is transferred from one anesthesia provider to another frequently throughout the day. ideally, one anesthesia provider would be responsible for the entire perioperative phase for a surgical patient; however, discontinuity of care is inevitable owing to shift changes, meal breaks, and staffing shortages. it is paramount that handoff processes be accurate, thorough, and concise to reduce errors, promote patient safety, and support a busy surgical schedule. many barriers exist in the surgical environment that threaten the integrity of the handoff process. such barriers include high background noise, high activity level, provider fatigue, operating room production pressure, interruptions during handoff, and lack of standardization of the handoff process. the critical importance of an accurate handoff and the significance of barriers to effective communication demand that nurse anesthetists develop strategies that contribute to patient safety and limit communication failures. failures in communication among health care providers account for 60% of the root causes associated with sentinel events reported annually to the joint commission.1 transfer of patient care, or “handoffs,” in the operating room occur for meal breaks, shift changes, and transfer of patient care to the post-anesthesia care unit or intensive care unit. jayaswal et al2 report that transfer of patient care between anesthesia providers occurs at least 5 times per operating room each day between 7:00 am and 3:00 pm. since many operating rooms conduct business well past 3:00 pm, the potential for errors and omissions of essential patient information during handoffs is considerable. an added impact to potential errors is the lack of standardization of the transfer of essential patient information during perioperative handoffs. some anesthesia providers will offer a thorough report that includes the patient’s name, allergies, past medical history, surgical procedure, perioperative medications given, fluid status, and anticipatory guidance, whereas others may point to the record and mention 1 or 2 items only. lastly, anesthetists must recognize the complexity of perioperative handoffs. petrovic et al3 emphasized that perioperative handoffs are multidimensional, involving the exchange of information and the transfer of technology, such as monitors, ventilators, transducers, and invasive lines for patients who are at higher risk for instability during this phase of care. abstract perioperative patient care handoffs are complex and multidimensional and require accurate attention to detail. communication failures among health care providers increase the risk of morbidity and mortality. use of a standardized handoff tool located within the electronic anesthesia record formalizes the handoff process and improves patient safety. i conducted 82 patient care transfer observations before the introduction of an electronic anesthesia handoff tool and 75 patient care transfer observations subsequent to the launch of the tool and made before and after comparisons. significantly (p<0.05) fewer errors were made in all categories of patient information after the introduction of the electronic anesthesia handoff tool. there were trends toward more handoff omissions after 3:00 pm, but the difference in most patient information categories was not significant (p>0.05). in addition, there were no significant differences in omissions related to the severity of patient comorbidities according to american society of anesthesiologists physical status classification. these findings provide information regarding the incidence of patient information inaccuracies and omissions during patient care transfer before and after implementation of an electronic patient care transfer tool. keywords: anesthesia handoff, electronic health record, patient care transfer anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 7 as stated previously, the joint commission reports that communication failures account for the majority of sentinel events.1 in fact, in an effort to close this gap in communication errors, the joint commission now requires hospitals to standardize handoff communications.1 in a study conducted by jayaswal et al,2 84% of anesthesia providers reported receiving a poor or incomplete handoff in the previous year; 57% reported giving an inadequate report in the previous year; and 25% of anesthesia providers attributed an adverse outcome to a poor handoff. hudson et al4 revealed that “handover of anesthetic care during cardiac surgery is associated with a 43% greater risk of in-hospital mortality and 27% greater risk of major morbidity.” mandating the use of a handoff tool that standardizes the patient information exchanged during transfers may be the key to preventing transfer-of-care events. for example, after standardizing patient handoff processes from surgery to intensive care, catchpole et al5 reduced the number of technical errors, the number of information omissions, and the duration of the handoff. in a retrospective study by wright et al,6 anesthetic adverse events occurred 3 times more frequently after 3:00 pm. these adverse events included improper dosing of anesthetic agents, difficulty intubating, prolonged sedation, wound infection, postoperative nausea and vomiting, pain management issues, and blood pressure changes. echoing this “afternoon effect,” scott et al7 discovered that the risk of error doubled when nurses worked greater than 12.5 consecutive hours. in an interview, dr. m. c. wright of the department of anesthesia at duke university medical center maintained that performance suffers after hours of working and stated, “handoffs and transition care might be improved by using shared displays, similar to computerized white boards, that provide data from different sources and are available for exiting and incoming staff to view at all times.”8 standardizing the information exchanged during the handoff process is the key to preventing adverse patient outcomes. the joint commission guidelines for the handoff process recommend incorporating “interactive communications, up-to-date and accurate information, limited interruptions, a process for verification, and an opportunity to review any relevant historical data.”9 some authors have standardized handoffs by using acronym tools on the premise that a checklist is easy to remember if it has an associated catch phrase, such as situationbackground-assessment-recommendation, or sbar, a communication tool widely used in nursing and hospital systems.9 wright10 developed an anesthesia communication tool that uses the acronym patient. each letter in patient represents 1 to 4 components of a typical anesthesia report; for example, the p represents procedure, patient, and position. to date, this is the only anesthesia-specific handoff tool noted in the literature. electronic health care records have gained popularity in the last decade, and anesthesia departments are utilizing electronic anesthesia records with increasing frequency. bosman11 concluded that incorporating protocols, hospital policies, and industry or department guidelines in the computerized information system will optimize workflow. computerized information systems improve patient safety by reducing errors in knowledge and ensuring that patient information and online databases are available at the provider’s fingertips.11 when one web-based computerized sign out system was trialed by residents, the tool reduced the number of patients missed on rounds, improved the quality of sign outs, and reduced the workload by 3 hours per week.12 few studies have been conducted to evaluate electronic anesthesia handoff tools. jayaswal et al2 conducted a pilot study of a mandatory electronic handoff tool contained in the electronic anesthesia record. the focus of the study by jayaswal et al2 was consumer satisfaction with current patient handoff practice and the development of an electronic handoff tool; a follow-up survey regarding satisfaction with the tool is pending. despite overwhelming evidence of inadequate patient transfers between anesthesia providers causing patient harm, no published studies are available regarding the effect of a standardized electronic patient care transfer tool on patient safety. despite advances in technology, human errors in medicine continue to occur with impressive frequency. furthermore, adverse anesthesia events occur more often after 3:00 pm. inadequate exchange of patient information during transfer of care significantly increases the risk for patient harm. perioperative handoffs require transfer of patient information, surgical information, medication information including response to medications, technology information, and anticipatory guidance.3 the development of a provider-friendly electronic handoff tool contained within the electronic anesthesia record has the potential to decrease errors and omissions during the exchange of information, thereby enhancing patient safety. the emphasis of this study was to compare the incidence of patient information inaccuracies and omissions during patient care transfer before and after implementation of an electronic patient care transfer tool. omissions during patient care transfer were also assessed in relation to the time of day and to american society of anesthesiologists (asa) physical status classification. materials and methods this study was conducted by use of a preintervention/ postintervention observational design. the researcher observed the transfer of patient care by one group of certified registered nurse anesthetists (crnas) before and after implementation of the intervention. before the intervention, the researcher collected data during intraoperative patient care transfers, recording any omissions and inaccuracies in the report on a 13item checklist. the researcher also recorded time of day, phase of case, number of providers, patient’s asa status, and duration of report. all observations of patient care transfer during an anesthetic were included. exclusionary criteria were patient care transfers completed by student nurse anesthetists and newly hired nurse anesthetists undergoing orientation. additional exclusions were made if patient care transfer communication was interrupted by patient care needs. each observation of patient care transfer information was recorded in written format to avoid any omissions by the investigator. the information was then transferred to the data collection tool. per usual practice, the patient’s electronic heath record was accessed to obtain the information required for patient care during the break or relief of the intraoperative case. after 82 patient care transfers were observed, the intervention was implemented by educating the staff crnas on the importance of appropriate patient handoff and the use of the tool. all crnas in the anesthesia practice were educated on the use of the handoff tool by a third party. the majority of the crnas were introduced to the tool at a staff meeting, where the chief crna provided education on the use and benefit of the electronic patient care transfer tool. any crnas not present at the staff meeting were provided individual education. after a 2-week period during which the staff crnas were allowed to acclimate to using the electronic handoff tool, 75 postintervention intraoperative patient care transfers were observed and recorded. the before and after observations were then compared to measure reductions in omissions and inaccuracies after implementation of the tool. demographic data on the crnas were collected via questionnaire after all observations were completed and included the participants’ gender, age, education, and years of practice (table 1). the data were entered into a password-protected database, and the questionnaires were stored in a locked cabinet. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 8 table 1. demographic data of the participants demographics staff crnas (n=10) no. % gender male female age 25-34 years 35-44 years 45-54 years 55-64 years education diploma degree bachelor’s degree master’s degree crna experience 1-4 years 5-9 years 10-14 years 15-19 years 20-24 years 25-29 years 30-34 years 35-39 years 3 7 2 3 3 3 0 3 7 0 3 4 0 0 0 2 2 30% 70% 10% 30% 30% 30% 30% 70% 30% 40% 10% 20% anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 9 the study site was sentara careplex hospital in hampton, virginia. a total of 16 fulland parttime crnas practice at sentara careplex hospital. the practice employs male and female crnas with a variety of educational backgrounds, years of experience, and a wide age range. targeted participants for the study were male and female crnas aged 25 to 70 years. the crnas practicing at sentara careplex hospital were automatically enrolled in the study. the principal investigator was studying routine practice habits; therefore, informed consent was waived. this study used a withinsubjects design; there was no randomization or control group. the electronic patient care transfer tool provided a formal structure for intraoperative patient handoff. the information recorded included details of patient name, allergies, health history, surgical procedure, airway/intubation, intraoperative events, hemodynamic status, medications, state of neuromuscular blockade, fluid status, pertinent laboratory values, and anticipatory guidance (figure 1). statistical analysis data were analyzed by using spss 20 software (ibm corp, armonk, ny) . demographic data related to sex were analyzed by using a chi-square test. interval demographic data related to age, years of practice, and educational level were analyzed by using descriptive statistics. a power analysis was performed for two-tailed analysis with alpha at p < 0.05, estimating an effect size at 0.7. independent two-tailed t-tests were used to evaluate the differences in omissions and inaccuracies of patient data during perioperative handoffs before and after implementation of the electronic patient care transfer tool. twelve patient care information items were identified as essential components of patient care handoff. data were then assigned to the following ordinal categories: 0=no omissions, 1=partial omission, and 2=full omission. omissions in all 12 categories were compared by using independent two-tailed t-tests with levene’s test for equality of variances (equal variances were not assumed). independent two-tailed t-tests with levene’s test for equality of variances (equal variances were not assumed) were used to analyze if there was a significant difference in perioperative handoffs provided before and after 3 pm related to omissions and inaccuracies of patient data. the spearman rank-order correlation coefficient was used to analyze the difference in the number of inaccuracies and omissions of patient data during patient care transfer based on asa physical status classification. figure 1. electronic patient care transfer tool anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 10 figure 2. omissions during patient care transfer before and after implementation of an electronic patient care transfer tool. abbreviations: i/o, fluid status; pmh, past medical history; nmb, state of neuromuscular blockade. results and discussion the demographic data of the crna participants are shown in table 1. three crna participants were male and 7 were female. the average age of the sample group was 48.3 years (sd: 10.8), with a range from 30 to 63 years. the average length of crna experience was 17.3 years (sd: 12.48). thirty percent of the crnas described their highest level of education as a bachelor’s degree (n=3), and 70% (n=7) reported holding a master’s degree. observations of 157 handoffs were conducted: 52% (n=82) before the introduction of the electronic patient care transfer tool, and 48% (n=75) after the introduction of the electronic patient care transfer tool. omissions were significantly reduced in all of the following patient information categories after the introduction of the electronic anesthesia patient care transfer tool: patient name, allergies, past medical history, surgical procedure, airway/intubation, intraoperative events, hemodynamic status, medications given, state of neuromuscular blockade, and fluid status (p = 0.000); pertinent laboratory values (p = 0.001); and anticipatory guidance (p = 0.005) (figure 2 and table 2). the anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 11 mean total number of omissions before the intervention was 12.78 (sd: 5.10), and the mean total number of omissions after the intervention was 4.05 (sd: 3.87). the difference in patient information omissions between the preintervention group and the postintervention group was significant (t = 12.14, p = 0.000). only 5 inaccuracies were noted during the observations: wrong allergy, wrong procedure, wrong medication dose, wrong laboratory value, and wrong ventilator mode setting. all 5 inaccuracies were observed in the preintervention group. of the 157 patient care transfers observed, 73% (n=115) were conducted before 3:00 pm and 27% (n=42) were conducted after 3:00 pm. of the 82 preintervention observations, 74% (n=61) were made before 3:00 pm and 26% (n=21) were made after 3:00 pm. of the 75 postintervention observations, 72% (n=54) were made before 3:00 pm and 28% (n=21) were made after 3:00 pm. there were trends toward more omissions after 3:00 pm in 11 of the 12 handoff categories in the preintervention phase; however, only one category (anticipatory guidance) was statistically significant (p = 0.05; table 3). in the postintervention phase, only 5 of the 12 handoff item categories had more omissions after 3:00 pm, with anticipatory guidance remaining the only statistically significant category (p = 0.04). thus, although the researcher predicted that patient care transfers would be more abbreviated during late afternoon hours as clinicians grew more fatigued or were anxious to leave, the difference in most patient information categories was not statistically significant. the sample size for the preintervention and postintervention groups was small (n=21). the preintervention group also had considerable numbers of omissions, with 25 omissions out of 25 possible omissions in one perioperative handoff. with the poor quality of patient care handoff observed in the preintervention group overall, there was not much prospect for omissions to increase after 3:00 pm. a larger sample size may have detected a difference. of the 157 patient care transfers observed, 4.5% (n=7) of the patients were classified as asa i; 34.4% (n=54) were classified table 2. omissions during patient care transfer before and after implementation of an electronic patient care transfer tool variable preintervention mean (sd) postintervention mean (sd) t p patient name 1.73 (0.69) 0.88 (0.99) 6.17 0.000 allergies 1.70 (0.71) 0.58 (0.90) 8.48 0.000 past medical history 1.41 (0.68) 0.44 (0.68) 8.93 0.000 surgical procedure 1.17 (0.99) 0.13 (0.50) 8.37 0.000 airway/intubation 1.13 (0.99) 0.43 (0.82) 4.88 0.000 intraoperative events 0.43 (0.82) 0.00 (0.00) 4.73 0.000 hemodynamic status 1.15 (0.98) 0.19 (0.59) 7.50 0.000 medications given 1.01 (0.71) 0.44 (0.60) 5.50 0.000 state of nmb 0.68 (0.95) 0.16 (0.55) 4.30 0.000 fluid status (i/o) 1.27 (0.93) 0.41 (0.79) 6.22 0.000 pertinent laboratory values 0.71 (0.95) 0.28 (0.69) 3.25 0.001 anticipatory guidance 0.39 (0.77) 0.11 (0.45) 2.85 0.005 total handoff items 12.78 (5.10) 4.05 (3.87) 12.14 0.000 note. abbreviation: nmb, neuromuscular blockade. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 12 table 3. omissions during patient care transfer related to time of day variable preintervention postintervention t p mean sd mean sd patient name before 1500 after 1500 1.77 1.61 0.64 080 0.89 0.88 1.00 1.01 pre 0.78 post 0.12 0.44 0.90 allergies before 1500 after 1500 1.66 1.81 0.75 0.60 0.52 0.76 0.86 0.99 pre -0.95 post -0.99 0.35 0.33 past medical history before 1500 after 1500 1.36 1.57 0.71 0.60 0.48 0.33 0.72 0.58 pre -1.33 post 0.93 0.19 0.35 surgical procedure before 1500 after 1500 1.08 1.42 1.00 0.93 0.11 0.19 0.46 0.60 pre -1.45 post -0.55 0.16 0.59 airway/intubation before 1500 after 1500 1.09 1.23 1.00 1.00 0.44 0.38 0.84 0.80 pre -0.56 post 0.30 0.58 0.76 intraoperative events before 1500 after 1500 0.33 0.71 0.75 1.00 0.00 0.00 0.00 0.00 pre -1.68 post 0.80 0.10 0.43 hemodynamic status before 1500 after 1500 0.98 1.29 1.00 0.96 0.15 0.29 0.53 0.72 pre -0.77 post -080 0.45 0.43 medications given before 1500 after 1500 0.97 1.14 0.68 0.79 0.43 0.48 0.60 0.60 pre -0.91 post -0.33 0.37 0.75 state of nmb before 1500 after 1500 0.66 0.76 0.95 0.90 0.15 0.29 0.53 0.60 pre -0.44 post -0.28 0.67 078 fluid status (i/o) before 1500 after 1500 1.26 1.29 0.95 0.96 0.46 0.29 0.82 0.72 pre -0.10 post 0.92 0.92 0.36 pertinent laboratory values before 1500 after 1500 0.70 0.71 0.95 0.96 0.31 0.19 0.72 0.60 pre -0.04 post 0.76 0.97 0.45 anticipatory guidance before 1500 after 1500 0.28 0.71 0.69 0.90 0.15 0.00 0.53 0.00 pre -2.02 post 2.06 0.05 0.04 total handoff items before 1500 after 1500 12.26 14.29 5.10 5.05 4.09 3.95 3.43 4.90 pre -1.58 post 0.12 0.12 0.91 note. abbreviation: nmb, neuromuscular blockade. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 13 as asa ii; 51% (n=80) were classified as asa iii; and 10.2% (n=16) were classified as asa iv. in the preintervention phase, 5 patient care transfer items were negatively associated with asa status: patient name, past medical history, surgical procedure, hemodynamic status, and fluid status (table 4). two patient care transfer items were significantly correlated with asa status: pertinent laboratory values and anticipatory guidance (p < 0.05). in the postintervention phase, 8 patient care transfer items were negatively associated with asa status (patient name, allergies, surgical procedure, hemodynamic status, medications given, state of neuromuscular blockade, pertinent laboratory values, and anticipatory guidance), with no items correlating to asa status. thus, there were no differences in inaccuracies and omissions related to the severity of patient comorbidities on the basis of the patients’ asa physical status classification. however, the distribution among the asa physical status categories was not proportional; there were many more asa ii and iii patients than i and iv. this distribution may have accounted for the nonsignificant findings. the negative spearman correlation indicated that there were fewer handoff omissions in the higher asa classes, which may suggest that practitioners caring for more critical patients provided a more thorough handoff. in the busy operating room environment, anesthesia providers care for patients undergoing intricate surgeries. with advances in medicine, critically ill patients are living longer and frequent surgical arenas worldwide. christian et al13 note that “complexity is manifest in the patient and treatment protocol, as well as the high level of technology and coordination required to effectively manage rapidly changing conditions.” with the added production pressure and time constraints of this setting, handoffs are often brief, rushed, or sometimes omitted altogether. these types of handoffs lead to confusion, reduce the opportunity for table 4. omissions related to american society of anesthesiologists classification status variable preintervention (n = 82) postintervention (n= 75) postintervention (n= 75) correlation coeff. p correlation coeff. p patient name -0.018 0.875 -0164 0.159 allergies 0.173 0.120 -2.17 0.062 past medical history -0.085 0.448 0.056 0.635 surgical procedure -0031 0.779 -0.208 0.073 airway/intubation 0.129 0.247 0.034 0.774 intraoperative events 0.058 0607 0 0 hemodynamic status -0220 0.047 -0.038 0.745 medications given 0.035 0.752 -0.233 0.044 state of nmb 0.054 0.631 -0.076 0.518 fluid status (i/o) -0.024 0.832 0.128 0.273 pertinent laboratory values 0.356 0.001 -0.020 0.863 anticipatory guidance 0.253 0.022 -0.027 0.818 total handoff items 0.095 0.396 -0.090 0.440 note. abbreviation: nmb, neuromuscular blockade. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 14 clarification, and compromise quality patient care.14 this study confirms previous findings that communication breakdown and loss of information occur during peri-anesthesia handoffs, threatening patient safety. utilizing an electronic anesthesia handoff tool within the electronic health record provides much needed structure to the complex communication and information flow. the results of this study were positive; however, further research is required to validate the effectiveness of the electronic patient care transfer tool in additional anesthesia settings and with a larger number of participants. this was the first study to observe perioperative handoff practices of crnas; additional studies investigating practice habits are needed. research in this area would provide guidance regarding interventions that enrich best practice. additional research regarding how electronic patient care transfer tools affect patient morbidity and mortality is required to further the crna impact on patient safety. inadequate handoffs result in a distressing number of patient injuries each year.15,16 this is due, in part, to a need for more scrutiny of communication patterns in health care and the fact that the majority of health care professionals do not receive formal education regarding transfer of patient care.14 the results of the present study show that standardizing transfer by use of a handoff tool contained in the electronic anesthesia record significantly reduces the number of omissions and inaccuracies during perioperative patient care transfer. in an effort to bolster patient safety, the joint commission required hospitals to employ standardized handoff communications over 8 years ago, yet many anesthesia departments have failed to implement any formal patient care transfer process.1 the patient care transfer tool created and tested in the present study satisfies the joint commission’s directive and has the potential to improve patient safety. this tool may close the gap in communication errors and prevent errors. if this tool is adopted system-wide, over 500 perioperative patient care transfers could be positively impacted each day. furthermore, this tool would enhance patient care transfers to the post-anesthesia care unit or to the intensive care units. communication patterns in health care require scrutiny. the majority of health care professionals do not receive formal education regarding transfer of patient care.14 teamwork training is integral in many high-risk professions like aviation and the military. further research into teamwork training with respect to the effectiveness of patient care transfer would expand the scholarship of this sizable problem. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 15 references 1. goldsmith d, boomhower m, lancaster dr, et al. development of a nursing handoff tool: a web-based application to enhance patient safety. amia annu symp proc. 2010;2010:256-260. http://www.ncbi.nlm.nih.gov/pmc/articles/pmc3041387/. 2. jayaswal s, berry l, leopold r, et al. evaluating safety of handoffs between anesthesia care providers. ochsner j. 2011;11(2):99101. 3. petrovic ma, aboumatar h, baumgartner wa, et al. pilot implementation of a perioperative protocol to guide operating room-to-intensive care unit patient handoffs. j cardiothorac vasc anesth. 2012;26(1):11-16. http://dx.doi.org/10.1053/j. jvca.2011.07.009. 4. hudson ccc, mcdonald b, hudson jkc, tran d, boodhwani m. impact of anesthetic handover on mortality and morbidity in cardiac surgery: a cohort study. j cardiothorac vasc anesth. 2015;29(1):11-16. http://dx.doi.org/10.1053/j.jvca.2014.05.018. 5. catchpole kr, de leval mr, mcewan a, et al. patient handover from surgery to intensive care unit: using formula 1 pit-stop and aviation models to improve safety and quality. paediatr anaesth. 2007;17(5):470-478. http://dx.doi.org/10.1111/j.14609592.2006.02239.x. 6. wright mc, phillips-bute b, mark jb, et al. time of day effects on the incidence of anesthetic adverse events. qual safe health care. 2006;15(4):258-263. http://dx.doi.org/10.1136/qshc.2005.017566. 7. scott ld, rogers ae, hwang w, zhang y. effects of critical care nurses’ work on vigilance and patients’ safety. am j crit care. 2006;15(1):30-37. http://ajcc.aacnjournals.org/content/15/1/30.long. accessed january 12, 2013. 8. arevalo jd. anesthetic adverse events vary based on time of day. anesthesia zone website. http://www.anesthesiazone.com/ featured-news-article.aspx?id=2366. updated 2007. accessed january 8, 2013. 9. patient safety primer: handoffs and signouts. ahrq patient safety network website. http://www.psnet.ahrq.gov/primer. aspx?primerid=9. updated october 2012. accessed january 8, 2013. 10. wright s. examining transfer of care processes in nurse anesthesia practice: introducing the patient protocol. j am assoc nurse anesth. 2013;81(3):225-232. 11. bosman rj. impact of computerized information systems on workload in operating room and intensive care unit. best pract res clin anaesthesiol. 2009;23(1):15-26. http://dx.doi.org/10.1016/j.bpa.2008.10.001. 12. van eaton eg, horvath kd, lober wb, rossini aj, pellegrini ca. a randomized, controlled trial evaluating the impact of a computerized rounding and sign-out system on continuity of care and resident work hours. j am coll surg. 2005;200(4):538545. http://dx.doi.org/10.1016/j.jamcollsurg.2004.11.009. 13. christian c, gustafson m, roth e, et al. a prospective study of patient safety in the operating room. surgery. 2006;139(2):159173. http://dx.doi.org/10.1016/j.surg.2005.07.037. 14. cohen md, hilligoss pb. handoffs in hospitals: a review of the literature on information exchange while transferring patient responsibility or control. 2009. deep blue website. http://deepblue.lib.umich.edu/handle/2027.42/61498?show=full. accessed january 12, 2013 15. institute of medicine. crossing the quality chasm: a new health system for the 21st century. washington, dc: national academy press; 2001. 16. wakefield mk. the quality chasm series: implications for nursing. in: hughes rg, ed. patient safety and quality: an evidencebased handbook for nurses. rockville, md: agency for healthcare quality and research; 2008, http://www.ncbi.nlm.nih.gov/ books/nbk2651/. accessed january 12, 2013. volume 7no. 6 2019 educated hand publishing llc “the science behind the art” volume 7 no. 6 2019 anesthesia ejournal online issn 2333-2611 page 17 intravenous magnesium sulfate for multimodal analgesia ashley noland, bsn, rn affiliation: texas christian university keywords: magnesium, analgesia, postoperative pain, multimodal abstract purpose statement magnesium sulfate has been used as a multimodal approach for analgesia as it may reduce opioid consumption in the first 24 hours after surgery and decrease post-operative pain scores. introduction the use of intraoperative opioids for analgesia is associated with postoperative side effects such as respiratory depression, ileus, nausea, and vomiting. the side effects from opioids can prolong hospital stay and cause patient dissatisfaction. magnesium acts as a n-methyl-d-aspartate (nmda) receptor antagonist resulting in an analgesic effect, which can be used as an alternative or adjunct to opioids for pain control. literature review magnesium sulfate may be beneficial for multimodal pain management as it reduces opioid requirements and postoperative pain. targeting various receptors in the pain pathway can optimize analgesia and reduce side effects. magnesium antagonizes the nmda receptor and blocks calcium channels to modulate pain and inflammatory responses. perioperative magnesium administration should be considered as a strategy to reduce postoperative pain in patients undergoing surgical procedures. description of the case a 67-year-old female presented for a bilateral breast revision, bilateral blepharoplasty of upper lids, neck rhytidectomy, and fat graft injection surgery. the patient had a history of postoperative nausea and vomiting. during the maintenance phase of anesthesia, fentanyl 50 mcg was given as needed for signs of pain, rocuronium was re-dosed to maintain paralysis, and ephedrine and phenylephrine were administered to maintain blood pressure. intravenous magnesium sulfate 2 g was administered as a multimodal approach to analgesia to decrease post-operative opioid consumption and to prevent post-operative nausea and vomiting. the following day the patient tolerated a regular diet, pain was well controlled, and was hemodynamically stable. the patient was discharged home without complications. discussion and conclusion magnesium sulfate may be beneficial for multimodal pain management as it reduces opioid requirements and postoperative pain. magnesium antagonizes the nmda receptor and blocks calcium channels to modulate pain and inflammatory responses. it is unclear which mode of magnesium administration provides an advantage to the analgesic effects. the differences in age and gender-related responses to magnesium for analgesia is undetermined. further research is necessary to examine the use of intravenous magnesium sulfate for postoperative pain in different patient populations, safe and effective dosing ranges, and the effects of analgesia in various surgeries. intravenous magnesium sulfate should be considered in multimodal analgesic treatment as an adjunct for postoperative analgesia. aej powerpoint template ©2009 texas christian university, center for instructional services. for educational use only. content is the property of the presenter and their resources. introduction § a multimodal analgesic approach with intraoperative magnesium sulfate may reduce opioid consumption in the first 24 hours postoperatively and decrease pain scores.1-3 § opioids can cause a range of side effects such as respiratory depression, postoperative ileus, nausea, vomiting, and hypercarbia.1,6,12 § inadequate pain relief impacts patient satisfaction and contributes to delays in recovery and increased hospital length of stay.11 § magnesium sulfate may be considered as an adjunct for intraoperative analgesia and an alternative to opioid-based therapy. § intravenous (iv) magnesium sulfate may minimize postoperative pain and decrease opioid consumption. § opioid tolerant patients present a challenge in achieving adequate postoperative pain control.6 § magnesium sulfate may be implemented to reduce opioid reliance and provide time-effective and safe postoperative recovery. § magnesium is a noncompetitive antagonist at the n-methyl-daspartate (nmda) glutamate receptor, which exerts a depressant effect (figure 1). § magnesium prevents central sensitization from peripheral nociceptive stimuli at the spinal cord action site by blocking nmda receptors. § magnesium also acts as a calcium channel blocker to inhibit calcium influx, which may contribute to the antinociceptive effects (figure 1). discussion § the presence of a painful stimulus causes the release of glutamate and mediates excitatory neurotransmission, which amplifies nociceptive stimuli.2 magnesium is a noncompetitive antagonist at the nmda glutamate receptor, which exerts depressant effects (figure 2).14 § magnesium is a noncompetitive calcium channel blocker (figure 1), which is one of the mechanisms of antinociceptive activity. § magnesium decreases the pre-synaptic release of acetylcholine (figure 1), which reduces the sensitivity of the motor end plate and decreases the amplitude of the action potential.2 § the increase of extracellular magnesium with iv magnesium sulfate inhibits the inflammatory response by reducing inflammatory cytokines.6 clinical rationale: § magnesium sulfate was given as a multimodal approach to decrease the amount of opioids required for pain relief and avoid the opioid side effects due to the patient’s history of postoperative nausea and vomiting. case critique: § magnesium sulfate 2 g iv (figure 4) was given to the patient during surgery mixed in a 1 l bag of plasmalyte infused as the maintenance fluid. § a bolus of 30 mg/kg of magnesium sulfate before induction was not given as mentioned in several of the studies, which may have provided additional analgesia.5 § currently, there is no standard criteria for perioperative use of iv magnesium sulfate.6 intravenous magnesium sulfate for multimodal analgesia ashley noland, bsn, rn, texas christian university case description § a 67-year-old, 88 kg, 172 cm, female presented for a bilateral breast revision, bilateral blepharoplasty of upper lids, neck rhytidectomy, and fat graft injection surgery due to malignant neoplasm of the breasts. § past medical history included breast cancer, osteopenia, celiac disease, and basal cell carcinoma of the face. § past surgical history included mohs surgery, breast lumpectomy, mastectomy with sentinel node biopsy, and breast reconstruction with a tissue expander. § the patient had a history of postoperative nausea and vomiting and was given aprepitant 40 mg po in pre-op. § pre-operative medication: midazolam 2 mg iv § pre-oxygenated with 100% oxygen at 10 l/min with a facemask for 5 minutes to reach an expired oxygen concentration of 90% § induction medications: fentanyl 50 mcg iv, lidocaine 100 mg iv, propofol 170 mg iv, rocuronium 50 mg iv, ketamine 30 mg iv § maintenance medications: fentanyl 50 mcg iv was given as needed for signs of pain, rocuronium iv was re-dosed to maintain train of four less than ¾, ephedrine and phenylephrine iv were administered to maintain blood pressure within 20% of baseline, magnesium sulfate 2 g iv, ketamine 10 mg iv every hour, dexamethasone 8 mg iv, acetaminophen 1,000 mg iv, sevoflurane at 1.5% in a mixture of oxygen 1 l/min and medical air 1 l/min. § emergence medications: sugammadex 200 mg iv and ondansetron 4 mg iv § fluid totals: plasmalyte 2,200 ml, urine output 625 ml, and estimated blood loss 25 ml § post-operative course: the patient was transported to the postanesthesia care unit with stable hemodynamics. the patient was admitted to the hospital to be monitored overnight. the patient received acetaminophen 650 mg po twice for pain control during their hospital stay. the following day the patient tolerated a regular diet, pain was well controlled, and hemodynamics were stable. the patient was discharged home without complications. references 1. egan td, newberry c. opioids. in: pardo mc, miller rd. basics of anesthesia. 7th ed. philadelphia, pa: elsevier; 2018:123-138. 2. burger k, warner a. effect of intravenous magnesium on opioid consumption among total knee arthroplasty patients. [master’s thesis]. saint louis: webster university; 2016. 3. pizzi lt, toner r, foley k, et al. relationship between potential opioid-related adverse effects and hospital length of stay in patients receiving opioids after orthopedic surgery. pharmacotherapy. 2012;32(6):502-514. doi:10.1002/j.1875-9114.2012.01101.x. 4. do sh. magnesium: a versatile drug for anesthesiologists. korean j anesthesiol. 2013;65(1):4-8. doi:10.4097/kjae.2013.65.1.4. 5. kaur s, baghla n. evaluation of intravenous magnesium sulphate for postoperative analgesia in upper limb orthopaedic surgery under general anaesthesia: a comparative study. the internet journal of anesthesiology. 2012;30(2):1-6. retrieved from http://ispub.com/ija/30/2/13941. 6. castro j, cooney mf. intravenous magnesium in the management of postoperative pain. j perianesth nurs. 2017;32(1):72-76. doi:10.1016/j.jopan.2016.11.007. 7. albrecht e, kirkham kr, liu ss, brull r. peri-operative intravenous administration of magnesium sulphate and postoperative pain: a meta-analysis. anaesthesia. 2013;68:79-90. doi:10.1111/j.1365-2044.2012.07335.x. 8. dabbagh a, elyasi h, razavi ss, fathi m, rajaei s. intravenous magnesium sulfate for post-operative pain in patients undergoing lower limb orthopedic surgery. acta anaesthesiol scand. 2009;53:1088-1091. doi:10.1111/j.1399-6576.2009.02025.x. 9. de oliveira gs, castro-alves lj, khan jh, mccarthy rj. perioperative systemic magnesium to minimize postoperative pain: a meta-analysis of randomized controlled trials. anesthesiology. 2013;119(1):178-190. doi:10.1097/aln.0b013e318297630d. 10. herroeder s, schönherr m, de hert sg, hollmann mw. magnesium: essentials for anesthesiologists. anesthesiology. 2011;114(4):971-993. doi:10.1097/aln.0b013e318210483d. 11. guo bl, lin y, hu w, et al. effects of systemic magnesium on post-operative analgesia: is the current evidence strong enough? pain physician. 2015;18(5):405-418. pmid:26431120. 12. arumugam s, lau csm, chamberlain rs. perioperative adjunct magnesium decreases postoperative opioid requirements: a meta-analysis. int j clin med. 2016;7(5):297-308. doi:10.4236/ijcm.2016.75032. 13. lysakowski c, dumont l, czarnetzki c, tramèr m. magnesium as an adjuvant to postoperative analgesia: a systematic review of randomized trials. anesth analg. 2007;104(6):1532-1539. doi:10.1213/01.ane.0000261250.59984.cd. 14. rege s. anti-n-methyl-d-aspartate receptor encephalitis: a synopsis. 2018. https://psychscenehub.com/psychinsights/anti-nmda-receptor-encephalitis-a-synopsis. accessed march 10, 2019. 15. us food and drug administration website. https://www.fda.gov/default.htm. updated march 18, 2019. accessed march 10,2019. 16. nagelhout jj, plaus kl. autonomic and cardiac pharmacology. in: nagelhout jj. nurse anesthesia. 5th ed. st. louis, mo: elsevier; 2014:186-211. conclusion/recommendations § opioids have traditionally been the basis of pain management, although significant risks and side effects are associated with opioids. § increased opioid administration is related to a higher incidence of respiratory depression, constipation, emesis, confusion, and prolonged length of hospital stay.3 § iv magnesium sulfate bolus of 30 mg/kg before induction followed by an intraoperative infusion at 10 mg/kg/hour resulted in significantly lower pain scores compared to a placebo group and decreased opioid consumption 24 hours following surgery.5 § dabbagh et al. found that the group that received magnesium versus the control group that received normal saline required significantly lower doses of iv morphine in the first 24 hours postoperatively.8 § postoperative administration of magnesium sulfate alone did not demonstrate a significant reduction in morphine consumption.12 § lysakowski et al. discovered in a systemic review of randomized trials for magnesium sulfate as an adjuvant to postoperative analgesia there was no evidence that perioperative magnesium had favorable effects on postoperative pain intensity and analgesic requirements.13 § further research is necessary to examine the use of iv magnesium sulfate for postoperative pain in different patient populations, safe and effective dosing ranges, and effects on analgesia for various surgeries. § perioperative magnesium sulfate administration should be considered as a strategy to reduce postoperative pain in patients undergoing surgical procedures.9 § iv magnesium sulfate is an alternative analgesic that may be valuable in reducing opioid consumption and beneficial for opioid tolerant patients. safety considerations for magnesium sulfate administration § avoid magnesium sulfate in patients with renal insufficiency because magnesium is excreted by the kidneys. § hypermagnesemia and toxicity can occur in renal insufficiency.6 § hypermagnesemia can cause sedation, cardiac arrhythmias, diarrhea, respiratory depression, and potentiation of neuromuscular blockade.11 § magnesium potentiates neuromuscular blockers; therefore, it should be avoided in patients with neuromuscular diseases because it can produce further muscle weakness by inhibiting acetylcholine release.16 § magnesium inhibits calcium channels at the presynaptic nerve terminals that trigger the release of acetylcholine (figure 1). also, magnesium ions have an inhibitory effect on post-junctional potentials and decrease the excitability of the muscle fiber membranes.16 § the dose of nondepolarizing neuromuscular blockers should be reduced in patients that receive magnesium sulfate and titrated carefully with a nerve stimulator to ensure adequate recovery of neuromuscular function at the end of surgery.16 § loss of deep tendon reflexes and respiratory or cardiac depression can occur at plasma magnesium concentrations above 10-12 meq/l.4 § magnesium slows sinoatrial node impulses and prolongs conduction time, which can cause heart block and should be avoided in patients with atrioventricular conduction abnormalities.4 figure 1. magnesium action sites 10 figure 2. nmda receptor activation 14 figure 3. iv magnesium sulfate 15 figure 4. magnesium sulfate vials 15 anesthesia ejournal www.anesthesiaejournal.com volume 7 no.6 2019 page 18 volume 6 no. 4 2018 educated hand publishing llc “the science behind the art” volume 6 no. 4 2018 anesthesia ejournal online issn 2333-2611 page 18 ultrasound-guided intrapec injection for breast surgery: a novel solution for surgical field improvement during electrocautery and implantation and for postoperative pain and muscle spasm reduction for breast surgery jonathan p kline, msna, crna affiliation: director of education at twin oaks anesthesia funding/conflict of interest disclosure: none acknowledgment we gratefully acknowledge dr. wayne lee md. for supporting this effort into new territory. keywords: intrapec, ultrasound, spasm reduction, electrocautery introduction regional anesthetic techniques for plastic surgery present a particular set of challenges for anesthesia providers. two recognized issues are the complex, wide, and sometimes not well described pain generators from the extensive areas involved with plastics procedures and the risk of last (local anesthetic systemic toxicity). the latter is arguably the result of additional doses of local anesthetics administered by surgeons in the form of tumescent fluid. for the past several years, pecs 1 and 2 blocks targeting the pectoral musculature have gained popularity as effective, opioid-sparing, multimodal painreducing techniques for analgesia for breast and anterior trunk surgical pain. the techniques continue to gain momentum for their ease of placement and safety, compared with prior techniques such as thoracic epidural and paravertebral blocks. in theory, the pecs 1 technique, involving ultrasound-guided placement of a local anesthetic between the pectoralis major and minor, should denervate the muscle group, reducing spasm and irritation caused by surgical manipulation and subsequent placement of expanders or implants. however, during pocket creation, these muscle planes are violated and may cause the complete release of the carefully placed local anesthetic, dramatically altering its expected duration of action. like all other nerve block techniques, the pecs 1 block does not cause intramuscular flaccidity during electrical dissection (electrocautery). this leakage of the local anesthetic away from the target nerves will ultimately reduce postoperative pain and spasm control. this spasm of the muscle has been a source of contention between our surgical colleagues and anesthesia since surgery with muscle relaxants began. the spasm and muscle contraction of the pectoralis major during the dissections and space creation for implantation remains problematic, despite denervation occurring at the myoneural junction through the pecs 1 technique. it is theorized that an ultrasound-guided injection of the pectoralis major muscle, done well ahead of the surgical dissection and space creation, might improve pectoralis muscle rigidity and spasm and potentially lessen trauma and bleeding during surgical techniques involving implantation. this may improve surgical field conditions during this phase of surgery and potentially reduce pain, spasm, and any need for intravenous muscle relaxants. it is also theorized that this technique may improve postoperative pain outcomes as a direct result of reduced muscle confrontation leading to trauma and spasm that occur during surgery. abstract this article introduces a novel ultrasound-guided injection called the intrapec technique as a solution to the specific problem of intraoperative pectoral major muscle spasm during electrocautery and manipulation. the technique is a costeffective, nonparenteral method for improving the surgical field during pectoral major isolation and subsequent implant placement. the technique may have added benefits such as a significant reduction in surgical complexity causing trauma and bleeding and significant reductions in postoperative pain and muscle spasm. aej anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 4 2018 page 19 background intramuscular injections for the relief of pain and spasm are not a new concept. pain management providers use a range of such techniques for a variety of ailments. examples include intramuscular injections for the relief of piriformis syndrome, iliotibial band release, and various posterior trunk musculature injections for trigger point treatment. these injections share commonalities that are all relieved by the injection of local anesthetic. additionally, they all involve elements of pain and spasm reduction, and the need for analgesic medicines. it is also possible that the evolution of chronic pain following breast reconstruction may originate from spasm and irritation of the pectoral compartment containing the medial and lateral pectoral nerves by the implant itself. surgical denervation of neuroma secondary to this pain syndrome is a common element for certain breast reconstruction procedures, sacrificing sensation in most cases and function in others. in many cases, this intramuscular injection can release spasm and pain. it is suggested that infiltration of the pectoralis major muscle (intrapec) can reduce the spasm of the pectoral major muscle during electrocautery and potentially into the recovery phase. review of the literature a pubmed (national library of medicine) search using the keyword “pectoral muscle injection” was performed and yielded several relevant articles. many of the articles suggested using the pecs blocks for acute and chronic pain treatment following breast surgery. interestingly, several articles reported postoperative treatment of existing pectoralis major muscle spasms with intramuscular injections of botulinum toxin type a (botox-a). however, we found no articles in which a preoperative ultrasound-guided intramuscular injection was used directly for the purpose of spasm reduction during surgery or to reduce postoperative pain. in 2011 o’donnell and colleagues successfully treated a patient with persistent post-breast-surgery pectoral muscle spasms with an intramuscular injection.1 this is one example of use of botulinum toxin type a (botox-a) treatment for pectoral muscle conditions related to surgery suggesting proof of concept for an intramuscular injection. govshievich and colleagues reported a case presentation involving, again, postoperative pectoral muscle pain after breast surgery.2 in that case, the authors used the novel pecs 1 block as a diagnostic measure to more accurately identify the pain generator for this persistent pain. the pecs 1 block was done using ultrasound with symptom relief. shin and colleagues described combination intramuscular injections of the subscapularis and pectoralis major muscles for the relief of postmastectomy shoulder pain.3 they found that postmastectomy patients benefitted from this combination technique. their technique described an intramuscular injection performed under ultrasound. however, again, it targeted postoperative treatment options for these persistent symptomatic patients. we found no mention of preoperative placement.3 in 2014 leiman and colleagues reported on the early use of liposomal bupivacaine (exparel) in an ultrasound-guided pecs 1 block for the management of postoperative pain after breast surgery.4 the technique involved the placement of a local anesthetic in the fascial plane between the pectoralis major and minor targeting the medial and lateral pectoral nerves. however, note that at the time of this writing, liposomal bupivacaine (exparel) is currently cleared only for infiltration type regional blocks but now includes interscalene “nerve blocks”. this is an important distinction specific to the pecs 1 approach because although targeting the medial and lateral pectoral nerves, it's accomplished by an infiltration of local anesthetic between the fascial planes created by the pectoral major and minor muscles. despite this limitation in the us, there are many articles that have described exparel’s safe and effective use in nerve blocks, such as the median and lateral pectoral nerve blocks in the pecs 1 approach. finally, trignano et al reported on the use of an injection of the pectoral muscle, using botulinum toxin type a (botox-a), for relief of pectoral muscle spasms in 2011.5 although the team reported favorable results of the intervention, the pectoral muscle was used as a flap for head and neck surgery, which is not exactly in league with this topic. however, mention of the technique is warranted to support proof of concept. patient presentation the surgeon and patient agreed to this technique being performed in the office-based outpatient surgical center. the patient was a 20-year-old woman, american society of anesthesiologists (asa) category 1, who was void of any comorbidities or prescribed home medications. she denied any prior surgical exposure, specifically breast procedures. she denied any allergies or illicit drug or alcohol use and was void of any physical or mental disabilities. the only discomfort she stated before the procedure was menstrual pain, which she characterized as moderate to severe. she presented to the office-based surgery suite with desire for bilateral breast augmentation. she was informed of the anesthesia plan involving general anesthesia with laryngeal mask airway, in combination with pecs 1, pecs 2, and the additional technique we termed intrapec injection. she demonstrated understanding of the risks and benefits and agreed to proceed. technique following explanation of the procedure to the patient, and prior approval from the surgeon, the patient positioned herself on the operating room table. an institutional time out was performed, and monitors and oxygen were applied. the patient’s baseline vital signs were recorded, preoxygenation was employed, and general anesthesia with placement of a laryngeal mask airway were easily performed. the skin was prepped with sterile chlorhexidine, and sterile single-use gel was applied to the suspected areas of interest. a probe cover (safersonic, highland park, il) was applied and the ultrasound image optimized. the ultrasoundguided intrapec technique was accomplished with the use of a high-frequency linear transducer (terason l15 paired with a terason 3300 ultrasound system, burlington, ma). the probe was positioned transverse over the anterior chest below the clavicle, beginning at the origin of the pectoral major medially, similar to that described by blanco for the pecs 1 technique. the inferior and posterior border was identified sonographically and was specifically targeted. an 80-mm, 22g echogenic needle (pajunk, germany) was introduced from medial to lateral into this discrete muscle region, following placement of the pecs 1 block. the goal of the injection was to concentrate local anesthetic to the aponeurosis of this anterior and inferior border of the pectoral major muscle. doppler mode was engaged to assist in the location of the vasculature in the region of interest. following aspiration anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 4 2018 page 20 and complete expulsion of all air from the needle, connective tubing, and syringe, a mixture of lidocaine 2% and ropivacaine 0.5% was infiltrated. a total volume of 15 ml per muscle was placed. the injection was safely performed in a medial to lateral fashion, promoting safety by directing the needle away from the deeper thoracic structures. see figure 1 for an actual patient ultrasound image of the intrapec procedure. the figure shows the right-sided intrapec technique. the needle is correctly placed into the anterior/inferior border of the pectoral major muscle. figure 2 shows the ultrasound-guided intrapec injection being performed. figure 3 is an illustration of an ultrasoundguided intrapec injection. figure 1. ultrasound image of the intrapec procedure. figure 2. performance of the ultrasound-guided intrapec injection. note the medial to lateral, in-plane, needle direction. figure 3 is an illustration of an ultrasound guided intrapec injection. results we report 2 aspects of this technique, the results from the surgeon’s experience during electrocautery and implantation, and the patient’s experience of pain after surgery. the surgeon stated that the creation of a surgical pocket was considerably easier and was accomplished without unpredictable muscle contraction during periods of electrocautery or manipulation via the lighted retractor. additionally, the surgeon stated that the surgical field was more easily maintained free of muscle spasm and bleeding. this seemed to promote ease of implant placement. the surgeon reported favorable results and was agreeable to reproducing the technique on future cases. the patient reported only “pressure” from the surgical procedure; however, she complained of intense menstrual pain. she also stated that she had more pressure-like discomfort to the right breast than to the left. it was clear that the incisional and surgical region was not causing the patient discomfort. however, she was given 1 oxycodone orally, per the surgical postoperative regimen, to ease her abdominal discomfort before her ride home. in the immediate post-anesthesia care unit area, and on postoperative day one, she had no pectoral muscle spasms and needed no pain medication for her surgical regions. discussion we made observations during the placement of the intrapec injection. first, the infiltration can be easily accomplished immediately following the pecs 1 block, as the needle is in nearly the correct position at that time. this suggests ease of placement and a small learning curve for those already using the pecs 1 block. during the surgical procedure, specifically, during the dissection and pocket creation of the pectoral major muscle, extremely little muscle contraction was seen during electrocautery. when asked how the pocket creation was compared with similar patients with similar presentations, the surgeon stated, “it was like the muscle was completely paralyzed.” this notion alone, that the problem of muscle spasm during electrocautery could be significantly improved with the simple addition of local anesthetic represents a bold step forward for both anesthesia providers and surgeons. this opens the door to more ultrasound-guided regional injections for a variety of purposes, potentially making optimal surgical fields less reliant on intravenous muscle relaxants. we recognize some limitations and drawbacks from the addition of the ultrasound-guided intrapec injection technique. the first element is the careful observation of the total dose of local anesthetic and potential of last. this element should be carefully considered because it is unique to this patient population and plastic surgery regarding the addition of tumescent fluid. the addition of tumescent fluid commonly incorporates larger volumes of local anesthetics as a part of the surgical regimen. because the intrapec technique is likely to be added to existing techniques such as the pecs 1 and 2 blocks, or other truncal techniques, this total dose should be carefully considered. muscle relaxation facilitated by local anesthetics is likely associated with a high concentration of local anesthetics; thus, careful consideration of total dose is advised. the potential for disastrous needle misadventure should also be mentioned. in novice hands, this technique may pose significant complications to the patient in the form of structure violation. this can lead to conditions such as cardiac tamponade, pneumothorax, or large vessel puncture, such as to the subclavian artery or vein. however, a more likely scenario might be puncture of a smaller vessel known to be in this region, such as the thoracoacromial artery. this artery is reliably found on ultrasound between the pectoralis major and minor during the pecs 1 block. it is possible for the surgeon to simply inject the inferior anterior border during dissection or under direct visualization following exposure. however, the delayed onset of the effect of this injection on reducing spasm and reactivity to electrocautery makes early infiltration (such as preoperative or following induction) sensible. it is likely that by the time the patient is ready for surgical dissection, the effects of the intrapec technique will have peaked. in addition, the safety of ultrasound guidance for vessel identification and needle guidance accuracy will be lost with a direct vision technique. a postoperative injection using the same technique could be suggested as well. however, preoperative placement without an implant yields natural muscular architecture, making the sonographic landscape easier to navigate. the incidental placement or trapping of air anywhere in the surgical field would have deleterious effects on the acquisition of ultrasound imaging. last, a fresh implant and carefully closed plastic surgery incision should be cautiously negotiated with further blocks. accidental opening of these incisions for the plastics patient can lead to further closure revision, undesirable scar formation, infection, implant violation, or other avoidable complications. this can be avoided by simply placing the intrapec injection before incision and plane rearrangement. conclusions the ultrasound-guided intrapec injection appears to enhance surgical field compliance during breast implantation for reconstruction and augmentation. the technique suggests that injecting the muscle itself, at the anterior/inferior border near the aponeurosis, may lead to less spasm, incidental trauma and bleeding, and reduced muscle confrontation to the surgeon. the placement of the injection is relatively simple and straightforward and can easily be accomplished in conjunction with a pecs 1 block. the technique is further made safer by the addition of ultrasound guidance. this seems evident by not only improved accuracy from an in-plane needle guidance, but avoidance of significant structures, arguably only centimeters away from the target zone. further safety is offered during the placement by the advantage of color doppler viewing to assist in identification of vasculature in the infiltration zone. we look forward to and recognize the need for more formalized studies investigating this simple technique of surgical field improvement and potential pain reduction for surgical patients undergoing breast expansion or augmentation. by its very nature of being both a novel technique and a single case study, we recognize that although successfully demonstrating proof of concept, this technique is in its infancy, and clearly more studies are required to validate its use. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 2018 page 21 references 1. o’donnell cj. pectoral muscle spasms after mastectomy successfully treated with botulinum toxin injections. pm r. 2011 aug;3(8):781-2. doi: 10.1016/j.pmrj.2011.02.023 2. govshievich a, kirkham k, brull r, brown mh. novel approach to intractable pectoralis major muscle spasms following submuscular expander-implant breast reconstruction. plast surg case studies. 2015;1(3):68-70. 3. shin hj, shin jc, kim ws, chang wh, lee sc. application of ultrasound-guided trigger point injection for myofascial trigger points in the subscapularis and pectoralis muscles to post-mastectomy patients: a pilot study. yonsei med j. 2014;55(3):792-799. https://doi.org/10.3349/ymj.2014.55.3.792 4. leiman d, barlow m, carpin k, piña em, casso d. medial and lateral pectoral nerve block with liposomal bupivacaine for the management of postsurgical pain after submuscular breast augmentation. plast reconstr surg glob open. 2014;2(12):e282. https://doi.org/10.1097/gox.0000000000000253 5. trignano e, dessy la, fallico n, et al. treatment of pectoralis major flap myospasms with botulinum toxin type a in head and neck reconstruction. j plast reconstr aesthet surg. 2012;65(2):e23-e28. https://doi.org/10.1016/j.bjps.2011.10.002 https://doi.org/10.3349/ymj.2014.55.3.792 https://doi.org/10.1097/gox.0000000000000253 https://doi.org/10.1016/j.bjps.2011.10.002 anesthesia ejournal volume 3 issue 1 2015 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 abstract a pilot study on student nurse anesthetists’ views on crna role transition purpose: understanding student nurse anesthetists’ views on nurse anesthetist role transition. design and methods: three focus groups were conducted with a total of 17 nurse anesthesia students. nurse anesthesia programs in the chicago area were contacted to elicit volunteers. discussions were audiotaped and transcribed verbatim. thematic analysis using constant comparison was completed within and across focus groups. findings: nurse anesthesia students defined successful role transition from rn to crna as the ability to function independently with minimal backup or assistance while ensuring patient safety through a successful anesthetic. the following themes were identified as factors affecting srnas’ successful role transition: preceptor, mentoring, reflection, training variety, and crna role modeling. conclusions: perceptions on which factors affect the role transition from rn to crna vary depending on the level of training srnas have had in their anesthesia program. srnas nearing the end of their training have a firmer grasp on which factors affect their transition. this pilot study has allowed this researcher to examine the perceptions of srnas at different levels in their training and allowed for future changes in planning for a full study. keywords: anesthesia training, nurse anesthesia, role transition crna role transition the transition from registered nurse (rn) to certified registered nurse anesthetist (crna) can be challenging and stressful. it is unclear which factors are associated with successful transition into the crna role because of the lack of research. previous research has argued that content on role transition needs to be developed and addressed throughout a crna program in order to be successful. 1,2 because role transition of the rn to crna has not been well studied, the initial plan will involve qualitative focus groups of rns who are currently going through the role transition to crnas to identify factors influencing transition. following the methodology of similar research, a study using focus groups was implemented to explore how student registered nurse anesthetists (srnas) think about their role transition and its influencing factors.3 methodology focus group methodology is considered a naturalistic approach.4,5 focus groups are viewed as a type of group interview to gain perspectives on specific issues. a strength of using focus groups as a technique is its ability to produce concentrated amounts of data on a specific topic.6 interaction between group participants adds to this combined perspective and creates a unique perspective different from individual interviews. this approach was selected to stimulate exchanges among study participants to elicit a broad range of contextualized responses to identify influencing factors. 3,7 a strength of using focus groups is that group dynamics can help participants analyze and clarify their views, which further enhances authenticity and credibility of the data.3,8 design traditionally, focus groups have consisted of 6 to 10 participants to allow input from all participants while gathering a breadth of opinions.3,4,6 this group size allows participants to hear opinions from other participants and have time for reflection on their own experiences.3 for this pilot study, 3 focus groups were selected. questions were designed to stimulate conversation through a design that gathers participants’ ideas, perceptions, and opinions. sampling qualitative research typically uses purposive sampling to select participants and is appropriate for focus groups.3,9 focus group participants were selected from the surrounding schools of nurse anesthesia, and a purposeful sampling method for gathering participants together based on their level of completion in their anesthesia training was planned. there are 3 schools of nurse anesthesia in the chicago area, which were contacted for study participants. andy tracy, msn, crna anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 1 2015 recruitment after institutional review board approval through the university of wisconsinmilwaukee the anesthesia programs were contacted for recruitment. approval was obtained from program directors to contact their students for study recruitment purposes. participants volunteered from two different schools, for a total of 17 nurse anesthesia students recruited. twelve srnas were in their second year of didactic coursework, with minimal clinical exposure, and the remaining 7 had completed about 5 months of full-time residency training. informed consent was obtained from all participants. collection data collection during focus group sessions were done via audio recordings. focus group sessions lasted about 2 hours each. all identifiable information was removed during transcription, and only the researcher had access to the recordings. no participant received any compensation to participate in this research. analysis thematic analysis was used to analyze the data and went beyond reading through the transcript to reading across the transcript with comparison between groups’ transcripts.11,12 throughout the process of coding, the investigator used the process of “constantly comparing” until categories emerged. data from each focus group were examined individually, and field notes of the primary researcher were examined during the analysis. data were also compared between focus groups, comparing themes and examining data for new themes. findings the following themes emerged (table 1). the findings were consistent across groups. the factors which srnas perceived as having the greatest influence on their role transition were preceptors and mentors, especially when they were experienced crnas, to which the srnas could look up to as role models. preceptors actively engaged and invested in the srnas’ education appeared to be of greatest influence. while preceptors who were not crnas were also noted as positive influences, srnas felt that working with crnas with whom they could identify and look up to fostered a smoother transition to their new role. theme meaning preceptor preceptors who were invested in the srna’s education and success. having the same preceptor during a rotation allowed faster progression. • supportive • respectful • fosters a progressive sense of autonomy and independence • allows time for critical thinking and problem solving • explains changes to anesthetics • stresses the importance of basic skills • allows comparison between anesthetic techniques and approaches mentoring • faculty mentoring • peer mentoring formal mentoring programs • supported throughout all levels of the program faculty mentoring • implemented at the start of the program rather than at the start of immersion residency peer mentoring • individual student mentoring by an advanced srna • groups allotted time for peer meetings to share ideas and experiences • meeting with students from other programs and sharing experiences reflection • self-reflection • group reflection self-reflection • performed while driving home group reflection • discussion with preceptor at the end of the day: “what did you learn today?” • sharing of experiences with trainees from other programs training variety exposure to a variety of training experiences which allows to srna to develop flexibility and critical thinking skills. • large academic centers: exposure to trainees in other professions (medicine, pharmacy, nursing) • smaller urban hospital: limited and often older equipment • small rural hospitals, especially hospitals with crna-only anesthesia groups • office practice settings: limited backup and forced autonomy experiencing crnas working with crnas in various practice settings. seeing crnas who practice independently, formulate their own anesthetics, and make autonomous clinical decisions. table 1: perceived factors positively influencing srnas’ role transition anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 1 2015 mentoring was perceived to be a positive influence on srnas during their training. formal mentoring, faculty mentoring, peer mentoring, and group mentoring programs supported throughout the program were listed. these allotted meetings for mentoring programs were times in which students could share ideas and experiences and seek advice from senior srnas, faculty, and formal mentors. also, participants felt peer mentoring with students from other programs helped foster successful transition through the sharing of experiences. peer mentoring and group mentoring appear to be tools that assist srnas during their training. reflection was found to be another common theme but not one openly discussed until it was mentioned in the focus group, and students learned that others were also using reflection. reflection has been used in other nurse specialties to promote role transition success, and srnas perceive it to be a positive influence during their transition.12 the types of reflection perceived to be beneficial included self and group reflections. exposure to a variety of training experiences were perceived by srnas as an asset in developing the flexibility and critical thinking skills needed to provide safe anesthesia care. srnas perceived large academic centers as a place for exposure to trainees from other professions. larger hospitals were perceived as places to learn flexibility. urban and rural hospitals were perceived as places in which srnas learned greater autonomy from viewing crnas, who functioned with autonomy and independence. while srnas viewed larger hospitals as providing exposure to a greater variety of technologies, smaller hospitals were perceived as places where they learned to function with limited supplies, older equipment, and limited support. office anesthesia practice settings were viewed by the srnas as settings of forced autonomy and limited backup and equipment. rigor and credibility threats to rigor and credibility were addressed throughout the study using established guidelines and as follows.9 recruiting participants from multiple locations helped reduce bias based on location and increase credibility of findings through external validation. continuous communication with the supervising professor throughout the study was performed to ensure systematic and transparent collection of data.13 follow-up verification of findings was performed with participants to ensure credibility of findings through phone conversations with randomly selected participants.14,15 limitations focus group methodology is not a reliable technique for eliciting or determining an individual’s point of view, but rather it is a group interview. individuals who are supportive during a focus group may have individual perceptions that are different. therefore, it is not possible or appropriate to assess each individual’s perceptions during a focus group study. this pilot study examined 3 focus groups. for a full study, 3 additional focus groups of srnas near the end of the residency training are needed to ensure data saturation. ideally, they will come from programs not previously sampled. ideally, these srnas would be recruited from 3 different training programs through the same process as the pilot study and from training programs in different regions of the american association of nurse anesthetists outside the midwest. conclusion this qualitative pilot study using focus groups examined the perceptions of srnas on their role transition from rn to crna by identifying factors that they feel are positively affecting their role transition. factors identified included preceptor, mentoring, reflection, training variety, and crna role modeling. this pilot study was not large enough to ensure data saturation, and a full study may identify other factors that positively influence role transition. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 1 2015 references 1. hamrick, a. b. & hanson, c. m. (2003). educating advanced practice nurses for practice reality. journal of professional nursing, 19(5), 262-268. 2. miller, a. b. (2012, august). attitudes and perceptions of newly graduated certified registered nurse anesthetists about their nurse anesthesia program’s ability to sufficiently educate graduates as full service providers. paper presented at the annual meeting of the american association of nurse anesthetists, san francisco, ca. 3. finch, h. & lewis, l. (2010). focus groups. in j. ritchie & j. lewis (eds.). qualitative research practice: a guide for social science students and researchers. (pp. 170-198). thousand oaks, ca: sage. 4. krueger, r. a. & casey, m. a. (2009). focus groups: a practical guide for applied research. (4th ed.). thousand oaks, ca: sage. 5. morgan, d.l. (2002). focus group interviewing. in j.f. gubrium & j.a. holstein (eds.), handbook of interviewing research: context & method (pp. 141–159). thousand oaks, ca: sage. 6. morgan, d. l. (1997). focus groups as qualitative research. (2nd ed.). thousand oaks, ca: sage. 7. kaplan, l. & brown, m. a. (2007). the transition of nurse practitioners to changes in prescriptive authority. journal of nursing scholarship, 39(2), 184-190. 8. grove, s. k., burns, n., & gray, j. r. (2013). the practice of nursing research: appraisal, synthesis, and generation of evidence. (7th ed.). st louis, mo: elsevier saunders. 9. polit, d. f., & beck, c. t. (2010). generalization in quantitative and qualitative research: myths and strategies. international journal of nursing studies, 47(11), 1451-1458. doi:10.1016/j.ijnurstu.2010.06.004 10. liamputtong, p. (2009). qualitative data analysis: conceptual and practical considerations. health promotion journal of australia, 20(2), 133-139. 11. riessman, c. k. (2008). narrative methods for the human sciences. los angeles, ca: sage. 12. poronsky, c. b. (2011). online faculty mentoring and transition balance in family nurse practitioner students (doctoral dissertation, university of wisconsin-milwaukee). retrieved from proquest dissertations & theses database. (umi no. 3510670). 13. northcote, m. t. “selecting criteria to evaluate qualitative research” (2012). education papers and journal articles. paper 38. http://research.avondale.edu.au/edu_papers/38 14. lewis, j. & ritchie, j. (2010). generalizing from qualitative research. in j. ritchie & j. lewis (eds.). qualitative research practice: a guide for social science students and researchers. (pp.263-286). thousand oaks, ca: sage. 15. giacomini, m. k. & cook, d. j. (2000). qualitative research in health care: are the results of the study valid? journal of the american medical association, 284(3), 357-362. reviewer summary: the manuscript provides the results of a completed pilot study on the view of student nurse anesthesia student role transition to crna. the strengths of the manuscript are the topic of role transition and use of focus groups. there are several recommendations to strengthen the manuscript, including further elaboration on the makeup of subject participants in regards to their standing within current nurse anesthesia programs and elaboration on future plans about recruitment of additional subject participants in nurse anesthesia programs. anesthesia ejournal volume 4 issue 1 2016 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 page 43 effectiveness of intravenous acetaminophen administration in the postoperative pain management of the cesarean delivery patient hazel pickering-luttrell, ms, crna johnny gayden ms, crna joseph pellegrini phd, dnp, crna affiliations: university of maryland, baltimore school of nursing conflicts/disclosures: none keywords iv acetaminophen, paracetamol, cesarean delivery, neuraxial anesthesia, postoperative pain introduction intravenous (iv) acetaminophen has been used internationally to relieve pain in many surgical arenas. with the recent release of iv acetaminophen (ofirmev; mallinckrodt pharmaceuticals) in the united states, many anesthetists have implemented using it for post-cesarean-delivery pain management, despite the lack of evidence supporting its use. an attractive feature supporting the use of iv acetaminophen in multimodal pain management for this population of patients is that it can reduce the overall side effect profile while reducing post-cesarean opioid consumption. intravenous acetaminophen is typically administered as a onetime dose at the end of the surgical procedure, and research supports its use in various surgical procedures.1,2 what makes iv acetaminophen so attractive in the cesarean delivery patient who has received regional anesthesia with neuraxial opioids is the limited number of medications available to treat any breakthrough pain. because of this, many practitioners began administering iv acetaminophen at the end of the cesarean delivery in an effort to reduce breakthrough pain and the need for supplemental opioids beyond those administered neuraxially. while there are many benefits for administration of iv acetaminophen, we should also discuss that a percentage of adult patients may have some adverse effects such as nausea, vomiting, insomnia, and headache. pediatric patients are susceptible to those adverse effects with a potential for pruritus, constipation, agitation, and atelectasis as well.3 this article aimed to explore the efficacy of iv acetaminophen use in multimodal therapy to decrease overall opioid requirements in post-cesarean pain management. our picot (population, intervention, comparison, outcome, time frame) research question thus examined the efficacy of iv acetaminophen as an adjunct to spinal anesthesia techniques with local anesthetics (bupivacaine and lidocaine) along with intrathecal opioids (fentanyl and morphine) in minimizing the incidence of rescue opioids or nonsteroidal anti-inflammatory drugs (nsaids) for postoperative pain management during the first 24 hours after cesarean delivery. the purpose of this evidenced-based literature review was to determine whether iv acetaminophen reduces opioid requirements in patients who have elective cesarean deliveries with neuraxial anesthesia. abstract intravenous (iv) acetaminophen has been used internationally as part of a multimodal approach to pain management for general surgeries and in some cesarean deliveries for postoperative pain management. in the case of post-cesarean pain management, however, little evidence supports the use of iv acetaminophen. the purpose of this evidencedbased literature review was to determine whether iv acetaminophen reduces opioid requirements for elective cesarean deliveries with neuraxial anesthesia. google scholar, cinahl, pubmed, cochrane, and medline were searched. articles addressing iv acetaminophen and cesarean delivery with neuraxial anesthesia were included. outcome measurements were specific for postoperative opioid requirements, pain control satisfaction, and visual analogue scores. the literature review resulted in 3 randomized controlled trials with a total of 225 patients, of which 112 received iv acetaminophen. two studies used fentanyl, and 1 used morphine. all articles found iv acetaminophen improved outcomes; 3 articles suggested that iv acetaminophen in combination with a nonsteroidal anti-inflammatory drug was more effective. analysis of the evidence revealed iv acetaminophen is a valuable component of multimodal therapy in the reduction of post-cesarean opioid requirements. on the basis of the current body of evidence, we can reasonably recommend iv acetaminophen for elective cesarean delivery patients using neuraxial anesthesia. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 44 analysis of the literature suggests that iv acetaminophen is effective in reducing surgical opioid requirements. arici et al1 conducted a prospective randomized controlled trial to evaluate the effectiveness of iv acetaminophen in patients undergoing total hysterectomy and found that 1 g iv acetaminophen 30 minutes before induction decreased visual analogue scale (vas) scores, decreased total morphine consumption over 24 hours, produced fewer side effects, and even decreased length of stay in the hospital. this study further purported that 1 g iv acetaminophen is comparable to 10 mg morphine.1 remy et al2 conducted a meta-analysis that showed acetaminophen, oral or iv, reduced morphine consumption in surgical patients of amounts up to 10 mg (approximately 20%) in the first 24 hours. it is important to note that this meta-analysis did not restrict its population to obstetric surgery and that acetaminophen was administered both intravenously and orally.2 the metaanalysis included a study by siddik et al,4 which examined a small sample of elective cesarean delivery patients who received neuraxial anesthesia, iv propacetamol (a prodrug form of acetaminophen), and oral diclofenac. in this study, diclofenac compared to propacetamol significantly reduced morphine consumption postoperatively.4 newer studies have replicated those results with a positive correlation in treatment with iv acetaminophen in conjunction with diclofenac for a decrease in postoperative opioid consumption.5 additionally, munishankar et al6 found that patients who received a combination of diclofenac and paracetamol required less morphine than did those given paracetamol alone. one limitation is the route of delivery for the medications; it was given as a suppository.6 the article failed to address whether diclofenac alone or paracetamol alone showed a significant difference. these studies were included to acknowledge that using a multimodal approach to pain therapy, including iv acetaminophen, is worthwhile. the limitations of this analysis include a small sample size of articles available for the literature search. the present article focused on the obstetric population undergoing cesarean delivery with spinal anesthesia. the independent variable examined was iv acetaminophen administered after spinal anesthesia using hyperbaric bupivacaine or lidocaine and intrathecal opioids. control groups included those who received placebo with iv opioids during the perioperative period. evaluated dependent variables included the incidence of rescue opioids using the different objective scales as outlined in appendix a. other studies included were for supportive information regarding pharmacokinetics and pharmacodynamics. history intravenous acetaminophen recently entered the market in the united states with the brand name ofirmev.3 patients who are unable to take medications by mouth or who may have absorption issues can be given this iv formulation as an adjunct in multimodal therapy in the perioperative period. many practitioners refrain from using iv ketorolac owing to patient allergies, platelet dysfunction, or renal status. however, iv acetaminophen may be used in place of iv ketorolac. opioid administration has a dose-dependent side effect profile that includes nausea, vomiting, and respiratory depression that can delay discharge times.3 additionally, the use of iv opioids is often limited in the cesarean delivery population owing to the concomitant administration of intrathecal opioids with a local anesthetic for postoperative analgesia, thereby limiting opioid administration within the first 24 hours following surgery.7 acetaminophen is a centrally acting analgesic and antipyretic; however, the exact mechanism of action is not completely understood.8,9 some authors have proposed that acetaminophen inhibits the nitric oxide synthesis pathway and inhibits prostaglandin synthesis.10 although other studies agree with the nitric oxide pathways, they also provide information about the possibility of inhibition of cyclooxygenase, opioidergic, n-methyl-d-aspartate receptor (nmda) inhibition, serotonergic, and endocannabinoid systems as a mechanism of action.7-12 acetaminophen dosing and administration considerations include hepatic first-pass metabolism and potential hepatic damage whether the route is oral, rectal, or iv. the bioavailability of medications administered affect timing for prescribing them in a multimodal therapy model. the maximum blood concentration (cmax) of acetaminophen given intravenously is 29 mcg/ml, that for the oral formulation is 14.2 mcg/ml, and that for the rectal formulation is 10.3 mcg/ ml.13 pharmacokinetic information indicates that dosing of iv acetaminophen does not reach the hepatotoxic levels of 150 mcg/ ml, even with repeat dosing.14 kulo et al15 collected plasma or urine samples from 39 women scheduled for elective cesarean delivery to evaluate the pharmacokinetics of iv paracetamol. eight of these women were then enrolled again for evaluation at weeks 10 and 15 postpartum for evaluation of clearance. according to their plasma concentration factors, women show a higher clearance of paracetamol at delivery than at 12 weeks postpartum. the information presented suggests that the likelihood of hepatotoxicity should be decreased. the article does note that because there is a higher clearance to potentially hepatotoxic oxidative metabolites at delivery, one may consider a higher dosing during this period. additional research is needed to determine the incidence of hepatotoxicity with the current recommended perioperative dose of 1 gram iv acetaminophen in elective cesarean delivery patients.15 moreover, hepatotoxicity has not been widely examined as an adverse reaction, even with a onetime dose. multimodal therapy is accepted as common practice today owing to its ability to be specific and sensitive to each patient’s pain management requirements. however, it should also be noted that the cost of iv acetaminophen has more than doubled in the united states between 2013 and 2014. the usual cost per dose to the hospital at wholesale was $12 to $13 in 2013 and is now more than $35.3,14 ordinarily, an increase in the price of the medication would translate to an increase in cost to the patient. because billing is typically a whole collected fee in the elective cesarean delivery patient population, research studies have not evaluated the cost-effectiveness of iv acetaminophen in this scenario. the cost-effectiveness of iv acetaminophen can also be an eliminating factor to a hospital’s choice to carry the drug on formulary and its consistent use within a particular population. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 45 review of the literature an extensive literature review was performed by using google scholar (google inc), cinahl (ebsco health), pubmed (us national library of medicine), cochrane library (cochrane), and medline (us national library of medicine) to evaluate the picot question. keywords used in the search were as follows: iv acetaminophen, paracetamol, cesarean section, spinal anesthesia, epidural anesthesia, neuraxial anesthesia, and postoperative pain. articles were excluded on the basis of pain medication, method of delivery, and year of available articles. any article older than 5 years was not included in the analysis, but may have been included in the supportive data. a total of 3 articles met all inclusion criteria. all 3 were prospective randomized controlled studies. three randomized controlled trials included a total of 225 patients, 112 of whom received iv acetaminophen. all studies utilized neuraxial anesthesia with an adjunct of fentanyl11,12 and morphine (duramorph; west-ward pharmaceuticals)8 for primary pain management and a prescribed multimodal pain management plan. all evaluated whether iv acetaminophen and neuraxial anesthesia had any impact on decreasing postoperative opioid requirements. two articles suggested that iv acetaminophen in combination with an nsaid was superior to iv acetaminophen alone.5,11 evaluation of the evidence in the articles is noted in appendix a; a critique of all 3 articles is noted in appendix b. analysis of the evidence revealed that iv acetaminophen is effective in reducing cesarean delivery postoperative opioid requirements.8,11,12 vas scores showed a statistically significant reduction (p<0.05) in the side effect profile at 4 hours and 24 hours postoperatively.8,11 the prospective randomized controlled trial by atashkhoyi et al12 showed an increased time to first analgesic and decreased time to ambulation with decreased cumulative postoperative analgesic consumption than the study group receiving a placebo. these findings were reinforced in another prospective, double-blind randomized placebo-controlled study by omar and issa8 with findings showing no rescue drug required in the iv acetaminophen group as compared to 25% of the control group who required multiple doses of meperidine for pain control. this can be attributed to adjunct administration of iv acetaminophen and is thought to be directly proportionate to decreased overall opioid requirements.8,11,12 alhashemi et al11 analyzed a spinal anesthetic technique with 8 to 10 mg of hyperbaric bupivacaine plus 10 mcg fentanyl and the effectiveness of iv acetaminophen compared with those of an oral nsaid as part of the multimodal pain management plan. a morphine iv patient-controlled anesthesia (pca) device with settings of 2-mg bolus, 10-minute lockout, and no basal infusion was included for opioid requirement measurement.11 atashkhoyi et al12 examined a spinal anesthetic technique with 1.5 ml of hyperbaric lidocaine and 15 mcg fentanyl. spinal anesthesia was confirmed and then the patients were randomized into 2 groups of patients receiving iv acetaminophen and a placebo, 20 minutes before the end of the procedure. omar and issa8 examined a spinal anesthetic technique with 8 to 10 mg of hyperbaric bupivacaine with 0.2 mg morphine (duramorph; west-ward pharmaceuticals). after a t4 sensory deficit was achieved, patients were randomly divided into 2 equal groups. one group received iv acetaminophen (1 g/100 ml) at the end of the procedure and every 6 hours for 24 hours. the second group received a placebo 100-ml infusion at the same time intervals.8 breakthrough pain, antiemetic therapy, and opioid consumption were measured throughout the perioperative period. a vas for pain measurement ranging from 0 to 10 was utilized throughout the studies. time to first analgesic rescue, ambulation time, antiemetic therapy, and hemodynamic changes were analyzed for the first 24 hours postoperatively. discussion although the studies followed a prospective design, some problems were noted in each. for example, in the study by alhashemi et al,11 a post hoc analysis showed 160 patients were needed to demonstrate a statistical difference and a follow-up study was not done. no statistical data were available at 48 hours postoperatively.11 in addition, the differing routes of medication administration between iv acetaminophen and oral ibuprofen could have confounded the outcomes. in terms of the second study by atashkhoyi et al,12 this research was published in a journal without the benefit of peer review and the authors did not elaborate on the study’s limitations. despite these limitations, the design was sound in that it was a randomized controlled trial and the findings were relevant, hence the reason this study was chosen for review. in the final study included for critical review by omar and issa,8 it was noted that the study used a convenience sample of 80 subjects, which may pose a threat to external validity. however, the use of a convenience sample is common in obstetric anesthesia protocols and all of the studies were done within standards of practice for clinical research and used appropriate statistical analysis. summary postoperative pain after cesarean delivery can be severe for some women and even debilitating for others. such pain prevents these mothers from being able to care for their newborn effectively. intravenous patient-controlled analgesia can be associated with incorrect programming, anxiety about selfadministering narcotics, patient ignorance, and sedation with or without respiratory depression.7 as a result, neuraxial anesthesia methods using spinal applications, with the addition of opioids, and patient-controlled epidural analgesia are being chosen more often as the primary method for pain control within the first 24 hours after delivery. these methods of pain control help prevent drowsiness and enable the mother to care for her baby. research that evaluates the effectiveness of iv acetaminophen in the obstetric population is limited. in this article, we assessed only those studies that looked at the effect of iv acetaminophen in comparison with other conventional analgesics administered at the time of cesarean delivery. although the literature was limited, we did show that iv acetaminophen was efficacious in reducing overall analgesic requirements and increasing postoperative maternal satisfaction without the adverse events associated with opioids or nsaids. a decrease in overall opioid requirements and an increase in patient satisfaction scores were achieved with iv acetaminophen. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 46 acknowledgments this review was conducted in partial fulfillment of the requirements for the master’s of science in nurse anesthesia at the university of maryland baltimore. we acknowledge the umb school of nurse anesthesia faculty for expert advice and guidance in this assignment. references 1. arici s, gurbet a, türker g, et al. preemptive analgesic effects of intravenous paracetamol in total abdominal hysterectomy. agri. 2009;21(2):54-61. 2. remy c, marrett e, bonnet f. effects of acetaminophen on morphine side effects and consumption after major surgery: metaanalysis of randomized controlled trials. br j anaesth. 2005;94(4):505-513. http://dx.doi.org/10.1093/bja/aei085. 3. mallinckrodt pharmaceuticals. ofirmev (acetaminophen) injection prescribing information. http://www.ofirmev.com/ downloads/pdf/ofirmevpharmacyfactsheet.pdf. updated 2014. accessed july 18, 2016. 4. siddik sm, aouad mt, jalbout mi, et al. diclofenac and/or propacetamol for postoperative pain management after cesarean delivery in patients receiving patient controlled analgesia morphine. reg anesth pain med. 2001;26(4):310-315. http://dx.doi. org/10.1097/00115550-200107000-00006. 5. darvish h, ardestani bm, shali sm, tajik a. analgesic efficacy of diclofenac and paracetamol vs. meperidine in cesarean section. anesth pain med. 2014;4(1):e9997. 6. munishankar b, fettes p, moore c, mcleod g. a double-blind randomized controlled trial of paracetamol, diclofenac or the combination for pain relief after cesarean section. int j obstet anesth. 2008;17(1):9-14. http://dx.doi.org/10.1016/j. ijoa.2007.06.006. 7. angle p, walsh v. pain relief after cesarean section. tech reg anesth pain manage. 2001;5(1):36-40. http://dx.doi.org/10.1053/ trap.2001.22794. 8. omar a, issa k. intravenous paracetamol (perfalgan) for analgesia after cesarean section: a double blind randomized controlled study. rawal med j. 2011;36(4):269-273. 9. jones v. acetaminophen injection: a review of clinical information. j pain palliat care pharmacother. 2011;25(4):340-349. http:// dx.doi.org/10.3109/15360288.2011.606293. 10. duggan s, scott l. intravenous paracetamol (acetaminophen): adis drug profile. drugs. 2009;69(1):101-113. http://dx.doi. org/10.2165/00003495-200969010-00007. 11. alhashemi j, alotaibi q, mashaat m, et al. obstetrical and pediatric anesthesia. intravenous acetaminophen vs. oral ibuprofen in combination with morphine pcia after cesarean delivery. can j anaesth. 2006;53(12):1200-1206. http://dx.doi. org/10.1007/bf03021581. 12. atashkhoyi s, rasouli s, fardiazar z, ghojazadeh m, marandi p. preventive analgesia with intravenous paracetamol for postcesarean section pain control. international journal of women’s health and reproduction sciences. 2014;2(3):131-137. http:// dx.doi.org/10.15296/ijwhr.2014.20. 13. singla nk, parulan c, samson r, et al. plasma and cerebrospinal fluid pharmacokinetic parameters after single-dose administration of intravenous, oral, or rectal acetaminophen. pain pract. 2012;12(7):523-532. http://dx.doi.org/10.1111/ j.1533-2500.2012.00556.x. 14. lewis an. iv acetaminophen (ofirmev). pharmacy times. http://www.pharmacytimes.com/publications/health-systemedition/2012/jan-2012/-iv-acetaminophen-ofirmev-. published january 25, 2012. accessed july 18, 2016. 15. kulo a, peeters m, allegaert k, et al. pharmacokinetics of paracetamol and its metabolites in women at delivery and postpartum. br j clin pharmacol. 2012;75(3):850-860. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 47 http://dx.doi.org/10.1093/bja/aei085 http://www.ofirmev.com/downloads/pdf/ofirmevpharmacyfactsheet.pdf http://www.ofirmev.com/downloads/pdf/ofirmevpharmacyfactsheet.pdf http://dx.doi.org/10.1097/00115550-200107000-00006 http://dx.doi.org/10.1097/00115550-200107000-00006 http://dx.doi.org/10.1016/j.ijoa.2007.06.006 http://dx.doi.org/10.1016/j.ijoa.2007.06.006 http://dx.doi.org/10.1053/trap.2001.22794 http://dx.doi.org/10.1053/trap.2001.22794 http://dx.doi.org/10.3109/15360288.2011.606293 http://dx.doi.org/10.3109/15360288.2011.606293 http://dx.doi.org/10.2165/00003495-200969010-00007 http://dx.doi.org/10.2165/00003495-200969010-00007 http://dx.doi.org/10.1007/bf03021581 http://dx.doi.org/10.1007/bf03021581 http://dx.doi.org/10.15296/ijwhr.2014.20 http://dx.doi.org/10.15296/ijwhr.2014.20 http://dx.doi.org/10.1111/j.1533-2500.2012.00556.x http://dx.doi.org/10.1111/j.1533-2500.2012.00556.x http://www.pharmacytimes.com/publications/health-system-edition/2012/jan-2012/-iv-acetaminophen-ofirmevhttp://www.pharmacytimes.com/publications/health-system-edition/2012/jan-2012/-iv-acetaminophen-ofirmevanesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 48 appendix a: evidence table for research studies author, year study objective/ interventions or exposures compared design sample (n) outcomes studied (how measured) results qualitya alhashemi et al (2006) to compare iv acetaminophen with oral ibuprofen in combination with morphine pcia after cesarean delivery with spinal anesthesia using hyperbaric bupivacaine and fentanyl randomized controlled trial n=45 women ≥ 37 weeks’ gestation scheduled for elective cesarean delivery under spinal anesthesia, randomized to receive iv acetaminophen q6h plus oral placebo or ibuprofen 400 mg q6h plus oral placebo. 1st dose given orally 30 min preoperatively all patients received morphine pcia for 48 h intraoperative newborn’s apgar scores recorded at 1 and 5 min postoperatively pain scores assessed q1h x 4 h, then q4h x48 h using the vas [0 (no pain) to 10 (worst pain)] at rest, documenting morphine requirements along with pcia attempts made and patient level of sedation postoperative adverse events such as nausea, vomiting, pruritus, respiratory depression, and oxygen desaturation patient satisfaction recorded [1 (extremely dissatisfied) to 10 (extremely satisfied)] 48 h postoperatively vas scores decreased similarly in both groups over time statistical decrease in the opioid requirement in both the iv acetaminophen and oral ibuprofen intervention groups (=0.001) iv acetaminophen is a reasonable alternative as an adjunct to morphine pcia after cesarean delivery for patients unable to receive nsaids ia atashkhoyi et al (2014) to evaluate the analgesic effect of preventive (20 min prior to surgery finish) 1 g iv paracetamol on postoperative pain and analgesic consumption during the 24 h after elective cesarean delivery using hyperbaric lidocaine with fentanyl prospective, randomized, and double-blind clinical trial 100 pregnant women, asa i-ii, aged 18-39 years, and term pregnancy undergoing elective cesarean delivery with spinal anesthesia patients preloaded with 10-12 ml/kg of lactated ringer’s solution after delivery patients randomly block-assigned to receive one of the 2 study solutions: 1 g iv paracetamol in 100 ml normal saline over 15 min and placebo group with normal saline alone, 20 min prior to the end of the procedure. time to first analgesic rescue, time of ambulation, and side effects (nausea, vomiting, sedation, and hemodynamic changes) were measured using a vas [ 0 (no pain) to 10 (worst pain)] in the pacu and during the first 24 h postoperatively increased time to first analgesic in the study group in the pacu (p<0.0001) and decreased time to ambulation (~5 h) than those in the placebo group (p<0.001) cumulative postoperative analgesic consumption was lower in the study group (p<0.001) preventive administration of 1 g iv paracetamol reduces the intensity of pain in the pacu and until 4 h after operation and analgesic consumption following cesarean delivery incidence of adverse effects did not differ significantly between 2 groups ia omar & issa (2011) to evaluate the analgesic efficacy of iv paracetamol (perfalgan) for pain control after cesarean delivery using hyperbaric bupivacaine with 0.2 mg of intrathecal morphine prospective, double-blind, randomized, placebo-controlled study experimental study-comparative effectiveness ordinal measurement patients were randomly divided into 2 equal groups by a table of randomization 80 asa i-ii women who had elective cesarean deliveries under spinal anesthesia with spinal morphine vas was used to evaluate pain level (0 = no pain to 10 = worst pain) at 6, 12, and 24 hours postoperatively by a resident and nurse who did not know about the treatment protocols satisfaction was evaluated at 12 and 24 hours postoperatively (1 = very unsatisfied to 5 = very satisfied). spss version 15 was used to analyze the data. student’s t-test, chi-square test, and mann-whitney u-test were used where appropriate for statistical analysis. p-value of < 0.05 was considered statistically significant in the iv paracetamol (group i), no patients required rescue drug compared to 25% in the meperidine (group ii) rescue medication group who required multiple doses to control pain (<0.05) median pain scores were less in group i at 6 hours [1 (range 1-6) vs. 3 (range 1-8), p = 0.002] at 12 hours [2 (range 0-5) vs. 3 (range 0-7), p = 0.031], and at 24 hours [1.5 (range 0-4) vs. 3 (range 1-8), p< 0.0001], respectively satisfaction was comparable in both groups iv paracetamol is an effective treatment option and can be used to reduce the requirement of rescue opioid drugs for pain control after cesarean delivery ia abbreviations: asa, american society of anesthesiologists; iv, intravenous; nsaid, nonsteroidal anti-inflammatory drug; pacu, post-anesthesia care unit; pcia, patient-controlled intravenous analgesia; vas, visual analogue scale. arating quality of study (newhouse et al., 2007). level: i: evidence from experimental study, rct, or meta-analysis of rcts. ii: evidence from quasi-experimental study. iii: evidence obtained from a nonexperimental study, qualitative study, or meta-synthesis. quality rating scheme: a: high – consistent results with sufficient sample, adequate control, and definitive conclusions; consistent recommendations based on extensive literature review that includes thoughtful reference to scientific literature. b: good – reasonably consistent results; sufficient sample, some control, with fairly definitive conclusions; reasonably consistent recommendations based on fairly comprehensive literature review that includes some reference to scientific evidence. c: low/major flaw – little evidence with inconsistent results; insufficient sample size; conclusions cannot be drawn. appendix b: critique table author, year study objective/intervention or exposures compared strengths weaknesses alhashemi et al (2006) to compare iv acetaminophen with oral ibuprofen in combination with morphine pcia after cesarean delivery with spinal anesthesia using hyperbaric bupivacaine and fentanyl -experimental study design with randomized controlled trial -institutional ethics committee approval/written informed consent obtained -clearly defined inclusion and exclusion criteria -groups were nearly equal size (n=22; n=23) -measurement scale was specific and sensitive -two-sided alpha=0.05 -power analysis of 90% showing appropriate sample size, low chance of type ii error -anova used at the allotted time course to analyze the effects of therapy -fisher’s exact test for postoperative analysis -number of pcia attempts analyzed with mann-whitney u-test (ordinal measurement) -statistical procedures completed using spss software -evaluating alternative but equal therapy for multimodal analgesia. no statistical differences noted for either adjunct therapy within 48 h postoperative time frame -results, discussion, and limitations identified weaknesses of the study -post hoc power analysis showed 160 patients necessary to demonstrate statistical difference -follow-up study not done -different route of administration (iv acetaminophen vs. oral ibuprofen) could account for lack of variance -limited applicability of study to patients undergoing cesarean delivery with spinal anesthesia with duramorph -no dose-response curves available for studied medications atashkhoyi et al (2014) to evaluate the analgesic effect of preventive (20 min prior to surgery finish) 1 g iv paracetamol on postoperative pain and analgesic consumption during the 24 hours after elective cesarean delivery using hyperbaric lidocaine with fentanyl -experimental study design with double-blind randomized controlled trial -institutional ethics committee approval/written informed consent obtained -clearly defined inclusion and exclusion criteria -groups were equal size (n=50; n=50) -measurement scale was specific and sensitive -two-tailed alpha=0.05 -power analysis of 80% showing appropriate sample size, low chance of type ii error -compared the efficacy of preventive administration of paracetamol with patients who received placebo to eliminate variables -provided a thorough statistical analysis in an effort to prevent a type ii error by analyzing the means using student’s t-test, medians using mann-whitney u-test, counts using fisher’s exact and x2 tests -statistical procedures completed using spss software -limitations of study not well discussed -no dose-response curves available for studied medications -patients were not followed up with regards to chronic pain management studies did not have preoperative analgesic injection (preemptive) group as an example of the importance of timing the dosage of iv paracetamol omar & issa (2011) to evaluate the analgesic efficacy of iv paracetamol (perfalgan) for pain control after cesarean delivery using hyperbaric bupivacaine with 0.2 mg of intrathecal morphine -experimental study design with doubleblinded randomized controlled trial -approval from institutional ethics committee/ written informed consent from patients -appropriate inclusion and exclusion criteria -randomization table for data assessed using x2 test, mann-whitney u-test, and fisher’s exact test where appropriate (p <0.05 is significant) results showed no statistical significance for patient demographics, but statistical significance for amount of rescue medications needed -limitations of the study clearly stated -small sample size -results limited to comparison of iv paracetamol, placebo group and rescue medication -non-probability convenience sampling may pose a threat to external validity abbreviations: iv, intravenous; pcia, patient-controlled intravenous analgesia. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 49 anesthesia ejournal volume 4 issue 1 2016 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 page 1 potentiation of a neuromuscular blocking agent postoperatively by a polypeptide class antibiotic: a case report jenna reeve, crna, dnp texas christian university, dr reeve was a student at the time of writing the manuscript. introduction neuromuscular blocking agents (nmbas) are administered as part of a general anesthetic to provide muscle relaxation during surgical procedures. examples of commonly administered nmbas are succinylcholine, rocuronium, vecuronium, and cisatracurium. other medications administered during the surgical procedure may interact with nmbas.1-12 for example, some antibiotics are known to potentiate the effects of nmbas. antibiotics are also commonly administered to surgical patients during the perioperative period as a prophylactic measure for postoperative surgical wound infections or are given intraoperatively as part of continued treatment or for a newly identified infection risk. although most antibiotics work by altering the membrane permeability of bacterial cells, they can also affect the neuromuscular junction by causing neuromuscular blockade.1-13 the polypeptide class of antibiotics has been identified as one group of antibiotics that can potentiate nmbas when administered during the perioperative period.1-12 this classification of antibiotics is thought to act at 2 independent locations of the neuromuscular junction.1,2,4,10,12 presynaptically, polypeptide antibiotics reduce the release of acetylcholine. additionally, polypeptide antibiotics inhibit the acetylcholine from reaching its specific receptor postsynaptically. this potentiating action of polypeptide antibiotics may make it challenging to reverse a neuromuscular block. although a specific medication or therapy to fully reverse antibiotic-induced neuromuscular blockade has not yet been discovered, researchers have attempted to reverse the neuromuscular blockade produced from the combination of polypeptide antibiotics and nmbas with calcium chloride and anticholinesterase medications.1,3,4,7-13 these attempts have been shown to be inadequate and may only temporarily reverse the block or may adversely prolong the duration of the block.1,3,4,7-13 time and ventilatory support are the only proven treatment for full recovery of neuromuscular blockade prolonged by this interaction.1-13 although the incidence of antibiotic-induced neuromuscular blockade is rare, it is important to be aware of this medication interaction and to know how to manage this potential complication.8 this report presents one such case with a review of the literature. abstract during multiple surgical procedures, neuromuscular blocking agents (nmbas) are administered as part of a general anesthetic to provide muscle relaxation. examples of commonly administered nmbas are succinylcholine, rocuronium, vecuronium, and cisatracurium. administration of other medications during the surgical procedure can cause unexpected interactions, such as affecting the action of the nmbas. the polypeptide class of antibiotics has been identified as one group of antibiotics that can potentiate nmbas when administered during the perioperative period. although the incidence of antibiotic-induced neuromuscular blockade is rare, it is important to be aware of this medication interaction and to know how to manage this potential complication. this report presents one such case with a review of the literature. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 2 case report a 45-year-old, 152-cm, 121-kg woman was admitted for an emergent laparoscopic appendectomy. the patient had abdominal pain for approximately 2 days prior to admission but had attributed the pain to her menstrual cycle. the patient denied any previous surgeries or procedures. her past medical history was significant for benign essential hypertension, but she was not taking any prescribed medications for this condition. recent and relevant laboratory data included a white blood cell count of 18.32 x 100/l. this laboratory value was elevated and was consistent with the diagnosis of appendicitis. the patient’s physical status was scored as american society of anesthesiologists (asa) iie related to the following conditions: chronic hypertension, body mass index greater than 40 kg/m2, and scheduled for an emergent surgery. a mallampati score of 3 and a thyromental distance of 3 finger breadths were noted during assessment of the airway with the patient in the upright and sitting position. range of motion capabilities were assessed and determined to be nonrestrictive. the patient was complaining of abdominal pain with nausea and vomiting. on the basis of the patient’s current condition, a general anesthetic with an endotracheal tube utilizing a rapid-sequence induction was determined to be the best anesthetic plan. in the preoperative area, metronidazole 500 mg and piperacillin-tazobactam 4.5 g were administered intravenously to help mitigate any potential infection risk associated with the patient’s ruptured appendix. morphine sulfate 5 mg was also administered intravenously to the patient prior to surgery to assist with pain relief. the patient was given 1 l of lactated ringers iv prior to induction to increase intravascular fluid volume and to help to prevent hypotension during induction. before leaving the preoperative area, the patient received famotidine 40 mg to reduce gastrointestinal ph. in the operating room, a pulse oximeter probe, an automatic blood pressure cuff, and electrocardiogram pads were placed on the patient. oxygen was delivered via a facemask at a rate of 10 l/min once the patient was appropriately positioned on the operating table. vital signs were assessed and were within the patient’s normal range. an intravenous induction was performed with fentanyl 100 mcg, lidocaine 50 mg, propofol 160 mg, succinylcholine 100 mg, and rocuronium 50 mg, while cricoid pressure was held, to assist with the rapid-sequence intubation. an endotracheal tube was smoothly and successfully inserted in one attempt under direct laryngoscopy. cricoid pressure was released after correct endotracheal tube placement was confirmed by auscultating bilateral breath sounds. desflurane was chosen as the maintenance anesthetic, with end-tidal concentrations maintained at 5.2%. rocuronium 25 mg was given 4 minutes after induction, when 4 twitches were present, prior to incision to provide sufficient muscle relaxation. no further rocuronium was given. controlled ventilation was maintained throughout the surgical procedure with ventilation settings of 600 ml for tidal volume and a respiratory rate of 13 breaths per minute. the endtidal co2 reading was approximately 35 to 38 mm hg throughout the procedure. before the completion of surgery, a lavage of the peritoneum was performed with an irrigant containing polymyxin b and bacitracin. a total of 100 mcg of fentanyl was given for the entire surgical case. three out of 4 twitches at the patient’s corrugator supercilii muscle were present upon assessment of train-of-four with a peripheral nerve stimulator at the end of the case. when the abdomen was no longer insufflated, neuromuscular blockade was reversed with a maximal dose of neostigmine (5 mg), along with glycopyrrolate (0.8 mg). the patient began spontaneously breathing within a few minutes of reversal at 12 breaths per minute with an unassisted tidal volume of 350 to 450 ml. two doses of labetalol 5 mg were also administered intravenously upon emergence because the patient’s blood pressure increased to 165/92 mm hg. the patient was successfully extubated after confirming a 5-s head lift and after appropriate responses to verbal commands were performed. the entire anesthetic and surgical procedure were uneventful except for the treatment of hypertension during emergence from anesthesia. immediately after the patient was transferred to the hospital bed with full assist of the operating room staff, respiratory weakness was noted. two-person assisted ventilation was initiated. the patient was responding to verbal commands and was able to move her upper and lower extremities with some weakness noted. however, she could not lift her extremities for more than 3 to 4 s. she could open her eyes but could not appropriately track movement. the anesthesiologist involved in the case was notified. thirty minutes after extubation, naloxone 0.04 mg was administered intravenously to determine whether the noted respiratory weakness was due to excessive narcotics. however, no apparent change in respiratory rate or effort was seen. the endtidal concentrations of desflurane were noted to be 0.0% at this time. ten minutes after the initial naloxone dose, an additional dose of 0.08 mg was given intravenously. the patient continued to follow some commands appropriately, but was only able to exert a tidal volume of 30 ml when not assisted. doxapram 40 mg was administered intravenously 5 minutes after the second dose of naloxone, followed by a second dose of 80 mg intravenously 10 minutes later. at this time the anesthesiologist went to discuss the current situation with the patient’s husband to determine if any recreational drug use had occurred recently. the husband reported that the patient had smoked marijuana 2 days before the surgical date. after the second dose of doxapram it was determined that the patient would require ventilator assistance and a size 4 laryngeal mask airway was successfully inserted. although no additional anesthetic was administered before laryngeal mask airway insertion, the patient did not show any signs of discomfort or have any changes in vital signs upon device insertion. the patient’s condition was reported to an intensive care unit registered nurse. because an intensive care unit bed was not yet available, the laryngeal mask was removed and an endotracheal tube was inserted to better protect the patient’s airway. while waiting in the operating room for a bed to become available, the patient began to cough, purposefully reach for the endotracheal tube, and produced adequate tidal volumes. the patient was subsequently extubated. within 5 of minutes of extubation, the patient once again began to have reduced tidal volumes. a nasal trumpet was inserted and two-person mask ventilation was initiated. the patient had spontaneous eye opening, with no tracking, but showed weakness when attempting to follow verbal commands. the patient was re-intubated, started on a propofol drip, and was transported to the intensive care unit. her vital signs remained stable during transport, and ventilation with 100% oxygen was assisted with a manual resuscitator. ventilator settings in the intensive care unit were simv (synchronized intermittent-mandatory ventilation) with a minimum of 8 respirations per minute. twenty minutes after arrival to the intensive care unit, the patient was extubated. the patient was able to effectively, spontaneously breathe without supplemental oxygen only 12 hours after being admitted to the intensive care unit. twenty-four hours later, the patient was discharged home in stable condition without sequelae. discussion antibiotics and nmbas are often administered to patients undergoing surgery requiring muscle relaxation. antibiotics can be administered by the anesthesia provider or by the surgeon. the type of antibiotic given varies depending on the type of surgery, the presence of infection, and the allergies of the patient undergoing the surgical procedure. the effects of different antibiotics on a cell membrane’s permeability are relatively well understood. however, the effects of certain antibiotics at the neuromuscular junction are still being researched and may be unpredictable. muscle relaxation during surgery can be achieved by using nmbas such as rocuronium, succinylcholine, vecuronium, and pancuronium. the patient in this case had a neuromuscular block initially produced by succinylcholine and then rocuronium. blockade from the succinylcholine was ruled out when 4 twitches were noted prior to the second dose of rocuronium. the neuromuscular blockade may have been prolonged when the polymyxin and bacitracin irrigant was administered and then further enhanced with neostigmine. before the reversal agents were administered to this patient, 3 out of 4 twitches for train-of-four were present, with sustained tetany that included fade. polymyxin, when administered alone, can cause fade upon train-of-four assessment, but will not show depression during assessment of tetanus.1,3,6,12 also, 4 out of 4 twitches can be seen with 70% of cholinergic receptors blocked or occupied.12 some antibiotics have been shown to augment nondepolarizing muscle relaxants by enhancing the neuromuscular block.1-13 polymyxins, along with other antibiotics, can have a synergistic effect on neuromuscular blockade produced by various muscle relaxants.1,4,6-12 polymyxins, bacitracin, and daptomycin are all examples of polypeptide antibiotics. polymyxins have also been shown to cause muscle weakness when administered without any nmba.1-2,5-7,9-10,12 polymyxin affects the neuromuscular junction at both the presynaptic and the postsynaptic level. at the presynaptic level it decreases the amount of acetylcholine released.1-6,12 at the postsynaptic level it blocks acetylcholine from entering specific receptor channels.1-6,12 each of these alterations at the neuromuscular junction has an effect on the action potentials in muscle tissue and nervous tissue. the polypeptide antibiotics affect the postsynaptic junction by noncompetitively antagonizing the acetylcholine-active channels on the endplate.2,4-5,10,12 an additive effect occurs when polypeptide antibiotics are administered with an nmba because the 2 types of drugs are acting on the same site. thus, if the cholinergic receptors at the postsynaptic junction are occupied with the nmba, the antibiotics can have a synergistic effect with the muscle relaxants by also being capable of affecting the presynaptic junction.12 although the specific method of action by which polypeptide antibiotics affect acetylcholine release and their receptor channels is not completely known, some studies have compared the actions of this antibiotic class to the actions of magnesium.2,4,12 at the neuromuscular junction, magnesium antagonizes calcium.2,4,12 calcium is necessary for acetylcholine to be released.2,4,12 therefore, magnesium inhibits the release of acetylcholine from the presynaptic junction. a few studies have revealed that the ed50, which is the dose that is effective in at least 50 percent of people, is significantly decreased when nmbas are combined with certain antibiotics.6,12 therefore, if a polypeptide antibiotic and an nmba are both required during the perioperative period, the anesthesia provider and the surgeon should discuss possibly decreasing the dosage of one of these drugs. decreasing the dosage of the nmba or the antibiotic will decrease the intensity of the block. furthermore, it is important to recognize that polymyxin can not only potentiate the neuromuscular blockade produced by an nmba but also cause some degree of neuromuscular blockade when administered alone.1-2,5-7,9-10,12 lindesmith et al9 in 1968 discussed cases in which patients experienced symptoms of neuromuscular toxicity due to polypeptide antibiotics without being given any nmba or other potentially neurotoxic antibiotics. the polypeptide antibiotics were administered intramuscularly to most of the patients.9 also, to prevent possible complications, polypeptide antibiotics and certain nmbas should be used cautiously in patients with altered renal function or myasthenia gravis.8 these patient populations are at higher risk for neurotoxicity and nephrotoxicity after polypeptide antibiotic administration.8 reversal of neuromuscular blockade caused by antibiotics is difficult, and attempts to reverse with calcium chloride and cholinesterases have not proven effective.1,3-4,6-12 although neostigmine is an acetylcholinesterase inhibitor, it can actually augment the neuromuscular blockade enhanced by polypeptide antibiotics.6 subclinical doses of acetylcholinesterase inhibitors may inadequately antagonize neuromuscular blockade and actually enhance the blockade at standard reversal dosages.1,3,6,7 this insufficient antagonizing of the neuromuscular blockade by neostigmine is seen only when nondepolarizing muscle relaxants are utilized.1,3-4,6-12 conversely, no change in the neuromuscular blockade intensity is seen after neostigmine administration when a depolarizing muscle relaxant is utilized.3,12 this difference is likely due to the nmba structure when binding to cholinergic receptors on the postsynaptic junction of the neuromuscular junction.3,7,12 another method of attempting to reverse this type of neuromuscular block is the administration of calcium chloride.1,3,7,12 calcium chloride has been shown to only temporarily improve the neuromuscular reversal.1,3,7,12 calcium levels that cause hypertension, tachycardia, and arrhythmias have been shown to not completely reverse this type of block.3 this temporary reversal could be due to how polypeptide antibiotics affect the neuromuscular junction at 2 independent anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 3 anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 4 levels.1-6,12 administering calcium chloride increases the release of acetylcholine at the presynaptic junction of the neuromuscular junction.1,2,4,12 however, increased levels of calcium chloride do not affect the polypeptide antibiotic at the postsynaptic junction of the neuromuscular junction because the calcium chloride acts as a noncompetitive antagonist to acetylcholine at the acetylcholineactivated channels of the endplate.3,7,12 calcium chloride as a reversal, although partially effective, may not be the best choice because the patient is likely to experience muscle weakness again shortly after initial recovery.13 also, calcium chloride administration could antagonize the antibiotic’s antibacterial effect.13 whether an nmba is administered in addition to a polypeptide antibiotic or administered alone, it is commonly recommended to administer a reversal agent for neuromuscular blockade caused by an nmba.14 although immediate recovery from neuromuscular blockade caused by nmbas is difficult to achieve, not administering a reversal agent after an nmba can cause residual weakness.14 also, confirming the presence of at least one twitch with a neuromuscular twitch monitor is necessary before administering the reversal agent to prevent further residual weakness. without at least one twitch, the patient is at risk for residual paralysis once the reversal agent is no longer at the neuromuscular junction.14 the commonly used reversal therapy for nondepolarizing nmbas is neostigmine. it is recommended that 0.04 to 0.07 mg/kg be administered to assist in the reversal of neuromuscular blockade, depending on the patient’s train-offour ratio.14 the greater the number and intensity of twitches, the less the amount of reversal needed.14 another cause of residual paralysis could be from overdosing a reversal agent, such as neostigmine. neostigmine acts by binding to the same receptor as the nondepolarizing neuromuscular blockers and would then cause further muscle weakness.14 although it is standard treatment to administer reversal agents for patients who receive nondepolarizing nmbas, it is also difficult to determine how much of the neuromuscular block is due to the nondepolarizing nmba and how much is due to the polypeptide antibiotic. the known recovery time for a block caused by both, nmbas and polypeptide antibiotics, or by only polypeptide antibiotics has yet to be discovered. the necessary recovery time can vary widely depending on the antibiotic and nmba administered. therefore, ventilation should be controlled in a patient who has received cyclic peptide antibiotics and muscle relaxants until standard requirements for extubation have been met and no signs of neuromuscular weakness are seen. these steps will decrease future unnecessary airway manipulation, irritation, and injury from re-intubations. additionally, during this recovery period, no further additional doses of neostigmine should be administered to prevent further muscle weakness. references 1. kronenfeld ma, thomas sj, turndorf h. recurrence of neuromuscular blockade after reversal of vecuronium in a patient receiving polymyxin/amikacin sternal irrigation. anesthesiology. 1986;65(1):93-94. http://dx.doi.org/10.1097/00000542198607000-00019. 2. durant nn, lambert jj. the action of polymyxin b at the frog neuromuscular junction. br j pharmacol. 1981;72(1):41-47. http://dx.doi.org/10.1111/j.1476-5381.1981.tb09102.x. 3. lee c, chen d, nagel el. neuromuscular block by antibiotics: polymyxin b. anesth analg. 1977;56(3):373-377. http://dx.doi. org/10.1213/00000539-197705000-00012. 4. singh yn, marshall ig, harvey al. preand postjunctional blocking effects of aminoglycoside, polymyxin, tetracycline, and lincosamide antibiotics. br j anaesth. 1982;54(12):1295-1306. http://dx.doi.org/10.1093/bja/54.12.1295. 5. fiekers jf. neuromuscular block produced by polymyxin b: interaction with end-plate channels. eur j pharmacol. 1981;70(1):77-81. http://dx.doi.org/10.1016/0014-2999(81)90435-0. 6. van nyhuis ls, miller rd, fogdall rp. the interaction between d-tubocurarine, pancuronium, polymyxin b, and neostigmine on neuromuscular function. anesth analg. 1976;55(2):224-228. http://dx.doi.org/10.1213/00000539-197603000-00021. 7. fogdall rp, miller rd. prolongation of a pancuronium-induced neuromuscular blockade by polymyxin b. anesthesiology. 1974;40(1):84-87. http://dx.doi.org/10.1097/00000542-197401000-00022. 8. kasiakou sk. toxicity of polymyxins: a systematic review of the evidence from old and recent studies. crit care. 2006;10:1-13. http://dx.doi.org/10.1186/cc3995. 9. lindesmith la, baines rd jr, bigelow db, petty tl. reversible respiratory paralysis associated with polymyxin therapy. ann intern med. 1968;68(2):318-327. http://dx.doi.org/10.7326/0003-4819-68-2-318. 10. sobek v. arrest of respiration induced by polypeptide antibiotics. arzneimittelforschung. 1982;32(3):235-237. 11. pittinger c, adamson r. antibiotic blockade of neuromuscular function. annu rev pharmacol. 1972;12(1):169-184. http:// dx.doi.org/10.1146/annurev.pa.12.040172.001125. 12. burkett l, bikhazi gb, thomas kc jr, rosenthal da, wirta mg, foldes ff. mutual potentiation of the neuromuscular effects of antibiotics and relaxants. anesth analg. 1979;58(2):107-115. http://dx.doi.org/10.1213/00000539-197903000-00010. 13. hasfurther dl, bailey pl. failure of neuromuscular blockade reversal after rocuronium in a patient who received oral neomycin. can j anaesth. 1996;43(6):617-620. http://dx.doi.org/10.1007/bf03011775. 14. brull sj, murphy gs. residual neuromuscular block: lessons unlearned. part ii: methods to reduce the risk of residual weakness. anesth analg. 2010;111(1):129-140. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 5 volume 6 no. 3 2018 educated hand publishing llc “the science behind the art” volume 6 no. 3 2018 anesthesia ejournal online issn 2333-2611 page 12 prophylaxis and treatment of hereditary angioedema with fresh frozen plasma: a synthesis and narrative review meredith mosier, rn, bsn, rrna1 j. dru riddle, phd, dnp, crna2 affiliation: 1. school of nurse anesthesia texas christian university, fort worth, tx. the author was a student at the time of writing. 2. assistant professor of professional practice, school of nurse anesthesia harris college of nursing and health sciences, texas christian university, fort worth, tx funding/conflict of interest disclosure: none keywords: angioedema, fresh frozen plasma, surgery introduction rapid intervention by a skilled team of clinicians is required when angioedema occurs in the operative setting. hereditary angioedema (hae), acquired angioedema (aae), and angiotensin-converting enzyme (ace) inhibitor-induced angioedema are 3 types of bradykinin-mediated angioedema.1 patients susceptible to bradykinin-mediated angioedema may experience a precipitating event before an acute episode occurs.1 airway instrumentation, upper airway trauma resulting from airway instrumentation, surgery, and psychologic or physiologic stress experienced by the patient may precipitate an exacerbation of angioedema.1 however, exacerbations can also occur in the absence of a triggering event.1 patients at risk for bradykinin-mediated angioedema are susceptible to airway compromise during or immediately after surgery. for susceptible patients, anesthetists should anticipate an exacerbation resulting in potential airway compromise. if a patient undergoing surgery is known or suspected to be at risk for bradykinin-mediated angioedema, prophylactic measures can be taken.2 pharmacologic prophylactic options include fresh frozen plasma (ffp), c1 esterase inhibitor (c1-inh), and androgen therapy.1 the present review aimed to answer the pico question, in patients with a known history of or suspected susceptibility to hae, does the administration of ffp compared with no infusion of ffp affect the occurrence or severity of angioedema postoperatively? this synthesis presents search strategies for the topic and reviews 6 articles (appendix a) pertaining to the above pico question. abstract patients with angioedema who experience an acute exacerbation may die if their symptoms are not treated promptly. airway compromise can occur if proper precautions are not taken. surgical patients with hereditary angioedema should undergo prophylactic treatment before surgical procedures to decrease the risk of an exacerbation. a literature search was performed using the embase (elsevier), cinahl (ebsco), health source: nursing/academic edition (ebsco), and medline (national library of medicine) databases. six articles were found that discussed administration of fresh frozen plasma (ffp) for treatment or prophylaxis against angioedema exacerbations. synthesis of the evidence suggests that use of ffp as a sole prophylaxis or treatment for angioedema is inappropriate. ffp can be used as part of a multimodal treatment plan for prophylaxis against angioedema if a c1 esterase inhibitor is not available. aej anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 3 2018 page 13 search methodology two structured searches were conducted. the embase database (elsevier) was searched by using the search terms “fresh frozen plasma,” “angioneurotic edema,” and “anesthesia” combined with the boolean operator “and.” the search was limited to articles published between 2000 and 2016. twenty-three articles were retrieved and 3 were selected for analysis.1,3,4 the second search was conducted of the cinahl (ebsco), health source: nursing/ academic edition (ebsco), and medline (national library of medicine) databases within the ebscohost platform search engine. the search terms “angioedema,” “fresh frozen plasma,” and “surgery” were combined with the boolean operator “and.” this search was limited to articles in english and retrieved 16 results. three articles were selected for review.5,6,7 in total, 6 articles were selected that best related to the stated pico question. the selected articles were classified according to the joanna briggs institute levels of evidence.8 a prisma flow diagram of the search is shown in appendix b.9 review of the literature limited quality research exists regarding ffp prophylaxis against an acute hae episode during the operative course. hae is an uncommon condition and, if an exacerbation occurs, it can be life-threatening.7 the rarity and severity of hae exacerbations make opportunities to conduct clinical trials almost nonexistent. the existent body of research therefore consists of case studies. two retrospective chart reviews, 1 expert opinion article, and 3 case reports were selected as the best evidence for inclusion. macbeth et al reviewed the medical records of 24 patients with bradykinin-mediated angioedema who received general anesthesia.1 the researchers searched for evidence of prior airway compromise, frequency of angioedema episodes, prophylactic treatment before surgery, and perioperative management. they also conducted a literature search of the medline database and located 19 case reports and 2 case series that described patients with angioedema who underwent general anesthesia. macbeth et al included data from the results of their database search in their discussion. we classified macbeth et al’s study as a level of evidence 3.b cohort study.8 although macbeth et al1 analyzed the largest amount of data compared with the other articles included here, their work had some weaknesses. the authors occasionally arrived at conclusions through speculation. for example, they speculated that, although the complication risk for patients who did not receive prophylaxis was low at 5.7%, using prophylaxis would further reduce the incidence of angioedema perioperatively.1 they also proposed that infusions of ffp could exacerbate an acute episode of angioedema because of the additional complement components ffp contains besides c1-inh. no source was cited to support this claim and it was stated that, because ffp contains complement components, it should be used as prophylaxis before surgery if no other treatment option is available.1 prematta and colleagues5 reviewed the medical records of all patients from their institution who were diagnosed with hae and received ffp from their institution’s blood bank. twenty-three cases were compiled. only 2 of these cases involved the use of ffp as prophylaxis before surgery. these 2 patients did not have an acute hae exacerbation postoperatively and the authors concluded that ffp is an effective treatment for surgical prophylaxis against hae. the authors identified weaknesses in their review and pointed out that no control group existed. thus, there was no way to be certain that infusions of ffp prevented an hae exacerbation. the amount of ffp administered to each patient was not consistent. the number and timing of doses varied among the patients discussed in the review. we classified this retrospective study as a level of evidence 3.b cohort study.8 szema and colleagues3 authored guidelines for the preoperative and intraoperative management of patients with hae. this article was a level 5.b expert consensus.8 the authors used literature retrieved from pubmed to construct the guidelines.3 they suggested giving 3 units each day before a surgical procedure and checking serum c1 and c4 esterase inhibitor levels after the first and second doses. the authors suggested transfusing 2 units of ffp intraoperatively. recommendations were graded based on the strength of supporting evidence. recommendations based on evidence from randomized controlled trials (rcts) were not provided because no rcts were located. shick et al6 wrote a case study, level of evidence 4.d,8 concerning a patient with hae who underwent coronary artery bypass grafting (cabg). the patient’s care team determined that cabg without cardiopulmonary bypass (off-pump cabg, or op-cabg) would be most appropriate.6 the care team chose this technique in an effort to minimize the risk of activation of complement cascade. the patient was given 2 units of ffp before incision and 2 units of ffp intraoperatively. the patient was later extubated in the intensive care unit (icu) without complication and discharged home 6 days after admission. several measures were taken to prevent an acute exacerbation of hae during the operative period, including an increased danazol dose preoperatively, use of the op-cabg technique, and infusions of ffp.6 the patient was also premedicated with intravenous doses of diphenhydramine, ranitidine, and hydrocortisone. these drugs have shown little benefit in patients with hae suffering an acute exacerbation.1 the role of ffp infusion as prophylaxis against an acute hae exacerbation cannot be absolutely determined from the evidence contained in the study. mihailovic et al4 authored a case study that described a patient with hae who underwent cabg on cardiopulmonary bypass. we assigned the study a level of evidence 4.d.8 the patient was prescribed danazol 3 days preoperatively. on the day of surgery, the patient received 2 doses of ffp 2 hours preoperatively and received 4 doses of ffp before successful extubation in the icu.4 the authors also used other prophylactic methods in addition to infusions of ffp. they reported that infusions of ffp raised the patient’s plasma levels of c1-inh and were instrumental in preventing an hae exacerbation. however, ffp cannot be solely credited for preventing the exacerbation, and the extent that ffp contributed to prophylaxis cannot be determined when other prophylactic measures are taken. a case study written by cifuentes and colleagues7 examined ffp as a treatment option for exacerbation of angioedema. the researchers reported the case of a patient with undiagnosed hae who underwent orthognathic surgery.7 the authors reported that the patient developed severe facial and upper airway edema on postoperative day 1. the patient was emergently intubated and received 2 units of ffp as a treatment for angioedema. the patient experienced a 10% reduction in edema 12 to 14 hours after the infusion and remained intubated for 24 hours. subsequently, anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 3 2018 page 14 the patient was extubated without complication and discharged 2 weeks later. this case did not describe the prophylactic use of ffp, but it did describe a rare scenario that may be encountered in the surgical arena. synthesis the research studies reviewed are inconclusive related to the value of ffp in hae prophylaxis because in all cases the investigators used multiple prophylactics. we did not identify any clinical trials investigating the effect of ffp on hae. administration of ffp as a treatment for acute exacerbations does not lend itself to clinical trial studies because occurrences are rare. when signs and symptoms of hae occur, the situation is acute and requires immediate, multimodal prophylactic measures to treat the condition. the use of ffp as the sole treatment in a clinical trial or withholding ffp to establish a placebo group is not appropriate. hae can be life-threatening, so when signs and symptoms appear, multiple therapeutic techniques should be used. patients in the cases studied received other prophylactic measures besides ffp infusions, including attenuated androgens, histamine antagonists, and corticosteroids. it has been determined that hae exacerbations result from deficiency of c1-inh and subsequent overproduction of bradykinin.1 the overproduction of bradykinin may lead to vascular permeability and hae exacerbation.1 researchers have concluded that exogenous c1-inh is a valuable component in treatment and prophylaxis against hae exacerbations. the food and drug administration approved cinryze (complement c1 esterase inhibitor) in 2008 for use as a routine prophylaxis against hae,3 but the drug is not widely available. because ffp is more readily available at hospitals in the united states than exogenous c1-inh, ffp has become a mainstay of treatment to be administered in conjunction with additional prophylactic measures. conclusion the information presented represents the best evidence available concerning the use of prophylactic ffp to prevent hae exacerbations. the pico question, in patients with a known history of or suspected susceptibility to hae, does the administration of ffp compared with no infusion of ffp affect the occurrence or severity of angioedema postoperatively, cannot be definitively answered. all the above studies included prophylactic measures such as administration of danzolol preoperatively, administration of antifibrinolytics, or administration of antihistamines in addition to ffp. the effect of administration of ffp without additional prophylactic measures on the occurrence or severity of angioedema cannot be determined from the evidence cited. acknowledgments this review was conducted in partial fulfillment of the requirements for the doctor of nursing practice degree at the school of nurse anesthesia at texas christian university. references 1. macbeth ls, volcheck gw, sprung j, weingarten tn. preoperative course in patients with hereditary or acquired angioedema. j clin anesth. 2016;34:385-391. doi:10.1016/j.jclinane. 2016.05.010. 2. levy jh, freiberger dj, roback j. hereditary angioedema: current and emerging treatment options. anesth analg. 2010;110(5):1271-1280. doi:10.1213/ane.0b013e3181d7ac98. 3. szema am, paz g, merriam l, stellaccio f, jen j. modern preoperative and intraoperative management of hereditary angioedema. allergy asthma proc. 2009;30:338–342. doi:10.2500/aap.2009.30.3225. 4. mihailovic s, volas l, arezina mihailovic a. hereditary angioedema type ii: perioperative management of coronary artery bypass graft surgery: 4ap2‐2. eur j anaesthesiol. 2012;29:55. 5. prematta m, gibbs jg, pratt el, stoughton tr craig tj. fresh frozen plasma for the treatment of hereditary angioedema. ann allergy asthma immunol. 2007;98(4):383-388. doi:10.1016/s1081-1206(10)60886-1. 6. shick v, sanchala v, mcgoldrick k, tartaglia jj, nelson j, fleisher aj. perioperative management of a patient with hereditary angioedema during off-pump coronary artery bypass graft surgery. j clin anesth. 2010;22(4):282-284. doi:10.1016/j. jclinane.2009.04.007. 7. cifuentes j, palisson f, valladares s, jerez d. life-threatening complications following orthognathic surgery in a patient with undiagnosed hereditary angioedema. j oral maxillofac surg. 2013;71(4):e185-e188. doi:10.1016/j.joms.2012.11.023. 8. levels of evidence and grades of recommendation working party. new jbi levels of evidence. the joanna briggs institute web site. http://joannabriggs.org/assets/docs/approach/ jbi-levels-of-evidence_2014.pdf. published october 2013. accessed april 20, 2016. 9. moher d, liberati a, tetzlaff j, altman dg. the prisma group. preferred reporting items for systematic reviews and meta-analyses: the prisma statement. plos med. 2009;6(7):e1000097. doi:10.1371/journal.pmed1000097. summary of key points hereditary angioedema (hae) is a rare disease but can have life-threatening consequences when an exacerbation occurs. situations in which patients with hae are at risk for an exacerbation include airway instrumentation, upper airway trauma resulting from airway instrumentation, and psychologic or physiologic stress experienced by the patient. knowledge of treatment options is paramount for anesthesia providers. • angioedema requires rapid intervention, including securing the airway and pharmacologic interventions to decrease severity of angioedema. • prophylaxis should be considered in patients with hae undergoing surgery. • hae exacerbations result from deficiency of c1 esterase inhibitor (c1-inh) and subsequent overproduction of bradykinin. • ffp contains c1-inh. • ffp may have some value in treating or preventing hae exacerbations if the fda-approved complement c1 esterase inhibitor (cinryze) is not available. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 3 2018 page 15 anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 3 2018 page 16 appendix a: annotated bibliography table author and year joanna briggs institute level of evidence methodology no. of subjects major findings, conclusions prematta et al, 2007 3.b cohort study reviewed literature and patient records to evaluate efficacy of ffp in treatment or prophylaxis of hae exacerbation. n=23 case reports of ffp being used as treatment or prophylaxis for hae ffp does not worsen acute exacerbation of hae. ffp is an effective surgical prophylaxis agent and treatment for acute exacerbations. macbeth et al, 2016 3.b cohort study retrospective review of medical records and review of published case reports of patients with bradykinin-mediated angioedema who underwent general anesthesia with airway manipulation. n=24 medical records of patients who had bradykinin-mediated angioedema and received general anesthesia plasma-derived c1-inh should be administered 1 hour before surgery and repeated daily after a major procedure until there is no remaining risk for exacerbation. ffp should be used only if no other treatment option is available. szema et al, 2009 5.b expert consensus reviewed literature regarding airway management and angioedema etiology and prophylaxis. developed guidelines for managing patients with hae preoperatively and intraoperatively. none stated preoperative protocol for management of patients with hereditary angioedema developed. mihailovic et al, 2012 4.d case study one case was presented involving a patient with hae undergoing cabg surgery. patient did not develop angioedema postoperatively. n=1 patient was successfully extubated without exacerbation of hae. patient received danazol 200 mg twice a day preoperatively, 2 doses of ffp preoperatively, and 4 doses of ffp after surgery and before extubation. shick et al, 2010 4.d case study one case was presented concerning a patient with hae undergoing off-pump cabg surgery. this patient did not develop angioedema postoperatively. n=1 the patient received 2 units of ffp before incision and 2 additional units of ffp intraoperatively. patient received other prophylactic treatment measures as well. the patient was successfully extubated in the intensive care unit. cifuentes et al, 2013 4.d case study one case was presented involving a patient with undiagnosed hae who underwent orthognathic surgery and developed facial and airway edema. n=1 the patient developed severe facial and upper airway edema on postoperative day 1 that required endotracheal intubation. the patient’s edema improved after administration of ffp, and the patient was discharged from the hospital 2 weeks after extubation. abbreviations: c1-inh, c1 esterase inhibitor; cabg, coronary artery bypass grafting; ffp, fresh frozen plasma; hae, hereditary angioedema. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 3 2018 page 17 prisma 2009 flow diagram records identified through embase database searching (n = 23) sc re en in g in clu de d el ig ib ili ty id en tif ica tio n records identified through cinahl, health source, medline (n = 16) records after duplicates removed (n = 39) records screened (n = 39) records not addressing pico (n = 33) full-text articles addressing pico (n = 6) full-text articles excluded, with reasons (n = 0) studies included in synthesis (n = 6) debunking volatile anesthetic cost myths between sevoflurane and desflurane introducing the volatile anesthetic cost calculator (crna ivac©) iapp john varkey crna, dnp and mark welliver crna, dnp introduction inhalational agents have been a mainstay in anesthesia practice. nitrous oxide, the world’s first inhalational agent, was synthesized in 1772 and is still in use today.1 by the late 1800s diethyl ether, and chloroform, volatile anesthetic agents (vaas) were introduced and administered by anesthesia professionals to facilitate surgery.1 volatile anesthetic agents, while inhalation agents, were liquids as opposed to a gas at room temperature. therefore, vaas were inhalation agents that were volatile (evaporated) emitting gases that produced anesthesia. halogenated (addition of cl, fl, br) hydrocarbon chain vaas were created in the 1940s and were safer, more stable, and more potent anesthetic agents.1 the early vaas had negative side effects and properties that included flammability, high incidence of nausea and vomiting, and high tissue solubilities causing prolonged wake up times (emergence). in order to meet the growing needs for a rapid acting and dissipating anesthetic agent for surgery, lower solubility volatile anesthetic agents (vaas) were created: isoflurane (1981), desflurane (1992), and sevoflurane (1995).1 nurse anesthetists have better control and timing of their anesthetic technique by using these lower solubility agents. the two newest and relatively more expensive agents, sevoflurane and desflurane, have many benefits including faster induction and emergence.2 using sevoflurane or desflurane may or may not increase the cost of anesthesia when compared to older vaas. is it beneficial to choose one of these newer agent’s based on cost differences between the two? determining the actual cost of specific vaas is important to many individuals and institutions that attempt to buffer the rising cost of healthcare by cost effective use of drugs and therapies. aejaej 17 background cost containment and cost effective use of resources has become a priority within healthcare. this has created a challenge for anesthesia providers wanting to deliver high quality healthcare that is safe yet economical. in anesthesia, vaas may account for up to 20% of total anesthesia costs.3 sevoflurane and desflurane are the two newest and more expensive vaas compared to isoflurane. each vaa has its own characteristic properties offering distinct advantages. sevoflurane is a potent non-irritating sweet smelling vaa that may be ideal for asthmatic patients and patients with reactive airways. sevoflurane is a versatile vaa that may be used for mask induction and maintenance of anesthesia. desflurane has the lowest blood gas and tissue solubility of all vaas, making it a preferential agent for rapid emergence and earlier cognitive function. populations that may benefit include the bariatric population and cases requiring neurological assessment immediately post op. apart from these distinct characteristics the cost for each vaa varies among institutions, purchasing contracts, and geographic locations. a difficult challenge for institutions is calculating and budgeting vaa cost. cost assessment for intravenous drugs is much simpler than vaas since individual and single dose packaging allows a direct correlation between the amount of drug acquired and that delivered per patient. calculating vaa drug cost, especially per patient, is made obscure by the delivery method. vaas are purchased in liquid form and administered through a vaporizer, making it difficult to directly measure how much vaa is used per case without the aid of additional measurement technologies. varying delivery concentrations and delivery techniques may increase or decrease total consumption of vaas and significantly change cost. review of literature to perform a cost analysis of sevoflurane versus desflurane, a thorough search of the literature was conducted which yielded ten articles that specifically calculated the cost of administering each vaa. these articles directly compared the cost of administering sevoflurane and desflurane. two of the articles were from randomized control trials (rcts). seven articles favored sevoflurane (table 1) as more cost effective when comparing similar flow rates, two articles favored desflurane (table 2), and one article found no significant cost difference between inhalation groups (table 3). seven methods were used to determine cost of vaa: a precision weighing system, a computer data log, minimum alveolar concentration (mac), a four compartment model, a volume percent formula, dion’s formula, and loke’s formula. precision weighing system boldt et al 4 performed a randomized control trial (rct) in 1998 comparing standard and new anesthetic techniques with cost. eighty patients undergoing laparoscopic cholecystectomy or a subtotal thyroidectomy were randomly divided into four groups. group 1 received propofol and sufentanil, group 2 received desflurane and sufentanil, group 3 received sevoflurane and sufentanil, and group 4 received isoflurane and sufentanil for anesthesia. a fresh gas flow (fgf) (aka carrier gases) of 1.5-2 l/min of oxygen and 60% nitrous oxide were used during maintenance. the average end tidal concentration of sevoflurane ranged from 1.1% to 2.5% and end tidal concentration of desflurane ranged from 3.5% to 7.2%. the authors were skeptical about the use of formulas and resorted to weighing vapors using a precision weighing machine. volatile anesthetic consumption was measured by weighing vaporizers after each case using a precision weighing machine. each agent was measured to the nearest 0.1 g and subsequently converted to ml (sevoflurane1.52g/ml, desflurane 1.465g/ml). the authors found no significant difference between the cost of using sevoflurane or desflurane. the authors opposed the use of a static formula to determine vaa cost because fgf rates are often adjusted throughout a case. according to the authors, the use of precision weighing machines allow for precise measurement of consumed aej liquid quantity. the reduction of fgf, regardless of vaa delivered, results in considerable vaa cost savings. theoretically the authors proposed desflurane would be more economical than sevoflurane at low fgf rates because equilibration (alveolar concentration to inspired concentration ratio, fa/fi) occurs more rapidly with desflurane. their finding was no significant difference in the cost of administering isoflurane, desflurane, or sevoflurane.4 computer data log cobos et al 5 at the university of nebraska medical center in 2007 used a computer to log fgf and inhaled concentrations of anesthetics every minute during 47 cases. the authors stated that sevoflurane fgf, mac equivalents, and cost per minute were higher than desflurane at their institution. average fgf for sevoflurane was 3.4 l/min and desflurane was 2.1 l/min, and cost per minute of sevoflurane was $0.79 and desflurane was $0.56. the authors did not mention how they determined cost of each vaa. the mac equivalents listed for sevoflurane is lower than desflurane at 0.90 and 1.12 respectively. a mac equivalent is the blood concentration of a vaa as opposed to mac which refers to alveolar gas concentration of a vaa. the authors proposed that reducing fgf by half may theoretically decrease the cost of all vaas by half. 5 although mac equivalents are useful and possibly a better representation of true anesthetic need for the patient actual vaa consumption (total amount taken from vaporizer) is what directly affects cost. minimum alveolar concentration a simple, but flawed, method to estimate cost is to compare acquisition costs of each vaa and assume it will cost three times as much to deliver desflurane compared to sevoflurane based solely on mac values. it requires only 2% sevoflurane to induce an equivalent mac produced by 6% desflurane. using this rationale some may assume that it will take three times the amount of desflurane to produce the anesthesia of sevoflurane. this assumption has previously been utilized and described in a 2009 pharmacy journal.6 it was claimed that, although sevoflurane is more expensive per unit than desflurane, it would take three bottles of desflurane to produce the anesthesia of one bottle of sevoflurane.6 this assumption is supported in part by an editorial in 2010 by dr. eger who stated that, although the unit cost of sevoflurane was more expensive than desflurane, it would take roughly three times the amount of desflurane to create a comparable anesthetic depth at a given fgf rate.7 this is due to their differences in potency, since approximately 2% of sevoflurane and 6% of desflurane is needed to create one mac. mac is defined as the minimum alveolar concentration of an inhaled anesthetic agent that produces immobility in 50% of the population exposed to a surgical incision.8,9 the erroneous assumption of direct mac to unit cost calculation ignores other variables involved in true cost calculation including the physics of vaporization, anesthetic delivery techniques, and fgf rates. actual consumption of a vaa determines cost not an assumed potencyto-potency comparison. despite stated institutional savings of $100,000 over one year no verifiable methods for calculating cost or vaa consumption were disclosed and no cost analysis was made. 6 additionally, these “savings” were achieved by removing desflurane from the operating suites and limiting anesthesia provider choice of agent to be used. 6 four compartment model lockwood and white 10 in 2001 incorporated the weiskopf and eger four compartment model to create a computer model to compare direct cost of isoflurane, desflurane, and sevoflurane in open and closed systems. the four-compartment computer model takes into consideration the solubility, absorption, and elimination of an anesthetic agent in the body. the original study by weiskopf and eger 11 compared isoflurane and desflurane which vary significantly in their solubility in blood. lockwood and white took weiskopf and eger’s methods and compared isoflurane, desflurane, and sevoflurane. they used actual patient data in a closed and open circuit system and compared it to a computer model. in the first part of their discussion, they predict aej ratio of liquid anesthetic used at fgf rates of 4, 2, 1, and 0.2 l/ min. the authors used their data to create ratio of liquid anesthetic used comparing desflurane to sevoflurane. unfortunately they did not mention the acquisition cost or formula used to determine cost. lockwood and white concluded that the ratios of usage shown are invariable and can always be used to determine relative expense. lockwood and white found in an open circuit system the cost of desflurane and sevoflurane are approximately the same, but in a closed circuit system (greater rebreathing of exhaled gases) desflurane is slightly less expensive than sevoflurane. clinical correlation of these findings is desflurane becomes less expensive than sevoflurane and more cost effective as fgf rates are decreased. lower fgf rates essentially make an open circuit system closer to a closed system by decreasing gases added and removed from the system and thus requiring more rebreathing of exhaled gases. vaporizer dial setting puckett and andrews 12 in 1997 calculated the cost of sevoflurane, desflurane, and isoflurane using the vaporizer dialed percent setting, the volume percent equation, the ml of vapor per ml liquid calculation, and the cost per ml of liquid vaa. the volume percent equation was used to calculate the amount of vapor produced at 1 mac and a fgf rate of 2 l/min. the vapor produced by one ml of vaa was calculated using the ml of vapor per ml liquid equation volume % = [vapor flow rate/(fgf + vapor flow rate)] x 100 the authors were then able to convert the amount of vapor into ml of vaa, and then they used the cost per ml to determine cost per hour. the authors assumed that the vaporizer dial setting accurately denotes the concentration of vapor being delivered. the authors did not establish calibration of the vaporizers pre-measurement nor confirmed accurate delivery output. they compared the cost of sevoflurane and desflurane at the same flow rate and found sevoflurane to be slightly less expensive.12 although these authors premise that actual consumptive use dictates cost, they did not allow for differences in fgf rates for the agents. fixed 2 l per minute fgf rate negates the real world clinical decision making of lowering fgf rates and the use of low flow anesthesia. dion’s formula in 1992 in a letter to the editor dion stated a formula for directly measuring the cost of inhaled anesthetic incorporating the ideal gas law.13 the cost of an anesthetic agent can be calculated from the concentration (%) of gas delivered, fgf (l/min), duration of inhaled anesthetic delivery (min), molecular weight (mw in g), cost per ml (in dollars), a conversion factor, 2412, to account for the molar volume of a gas at 21ºc (24.12 l), and density (d in g/ml). the formula is as follows: cost ($) = [(concentration)(fgf)(duration)(mw)(cost/ml)] [(2412)(d)] dion’s formula incorporates ideal gas law in order to convert ml vaa vapor into ml of vaa liquid, which is then used to determine cost using the acquisition price per ml. in order to convert volume of vapor into an ml of vaa, the density and molecular weight are used to convert the vaa vapor into moles, and moles are subsequently converted into ml of liquid vaa using a conversion factor of 2412. according to the universal gas law equation, one mole of an ideal gas at one atmosphere pressure and corresponding to 21ºc will liberate 24.12 liters of vapor. dion’s formula does not take into account patient specific uptake and distribution but rather amount of delivered inhaled agent. the amount of vapor actually consumed determines cost, which makes dion’s formula a reliable method in cost calculation. additionally, the incorporation of fgf rate better represents real world use of different fgf rates for different vaas. seven articles were found in the literature search using dion’s formula, and all five supported sevoflurane as a more economical aej inhalation agent than desflurane.6,12,14-18 unfortunately, comparisons were made using similar fgf rates for each vaa. loke’s formula loke and shearer, in a letter to the editor in 1993, questioned the use of dion’s formula in newer volatile agents.19 they used dion’s original formula and incorporated the ideal gas law directly into the formula rather than using a conversion factor of 2412 for 24.12 liters, which represents molar volume of gas at one atmosphere at 21ºc. for comparison purposes: loke’s formula cost per mac hour ($) = [(mac)(fgf)(60min)(mw)(cost/ml)] [(pressure/(rt))(d)] dion’s formula cost per mac hour ($) = [(mac)(fgf)(60min)(mw)(cost/ml)] [(2412)(d)] these formulas are similar; however with loke’s formula the user would substitute the atmospheric temperature in pascals, the ideal gas law constant (r) 8.314, and temperature (t) in kelvin for the constant 2412. loke and shearer also included the cost of carrier gases nitrous oxide and oxygen for comparisons of halothane, enflurane, and isoflurane. unfortunately, desflurane and sevoflurane were unavailable in australia at the time of this publication and comparison of these agents was not conducted. discussion determining cost of vaa is a difficult task, made even more challenging by the various methods available to determine cost. of the seven methods discovered in the literature, six were found to be either impractical or inaccurate. weighing vapors is impossible to replicate in a busy operating room setting.4 the computer data log method5 and four compartment model methods10,11 do not disclose cost calculation, making it difficult to determine accuracy. a simple comparison of mac6 does not factor in important variables such as fgf and differences in vaa properties. using the volume percent calculation is inaccurate since it is based on a dialed concentration and not an actual concentration determined by a gas analyzer.12 loke’s formula includes atmospheric pressure and temperature making it a more specific version of dion’s formula but not necessarily a more accurate on because cost comparison would likely occur at the same facility and the atmospheric pressure and temperature would remain relatively constant. thus, the use of loke’s formula is unnecessarily complicated. dion’s formula, in addition to being the most referenced method for calculating cost in the literature, is easily performed mathematically, accurate, and reproducible. as stated by weinberg et al “this method is a simple pharmacoeconomic tool that can be used by every anesthetist.”15p853 for these supporting reasons dion’s method was utilized in the creation of a resource iapp tool. the majority of the literature supports sevoflurane6,12,14,15-18 as the most cost effective agent using similar fgf rates. (table 1) three studies supported cost effectiveness of desflurane.4,5,10(table 2) several articles advocate the use of low fgf rates4,5,14,16, however only one16 makes a case for comparing each agent at each agent’s lowest allowable fgf rates. currently in the united states the fda recommends fgf rate no less than 1 l/min for cases less than 2 mac hours and fgf 2 l/min for cases longer than 2 mac hours for sevoflurane.20 desflurane has no restrictions on fgf rate and may be administered with fgf as low as 0.5 l/min. the comparison of sevoflurane and desflurane at lowest allowable fgf rates is the most accurate method in determining true cost in clinical practice. two of the seven studies that favored sevoflurane as most cost effective with similar fgf rates favored desflurane as the more cost effective agent when the lowest allowable fgf were used compared for cases less than two mac hours (table 3), and three studies favored desflurane when comparing cases longer than 2 mac hours (table 4). the impact of fgf rates and the cost savings of low flow anesthesia is emphasized by these tables. conclusions that one drug is more or less cost effective than another cannot always be translated from one region to another because of the variability in drug acquisition cost and availability of generic formulations (eg, sevoflurane). therefore in some institutions sevoflurane may be less expensive than desflurane and in others the opposite may hold true. using dion’s formula, a cost comparison was made using acquisition prices in california and in florida 2010. the variability in cost across regions and fgf is evident in the following examples. in california, the cost of sevoflurane was $0.38/ml and the cost of desflurane was $0.61/ml (known to author). using dion’s formula, a comparison was made at lowest allowable flow rates for cases less than 2 mac hours. for cases less than two mac hours, sevoflurane was cheaper to administer than desflurane at lowest allowable fgf rates. vaa mac % fgf cost/bottle ml/bottle cost/ml cost/min cost/mac hr sevo 2% 1 l/min $93.93 250 ml $0.38 $0.04 $2.46 des 6% 0.5 l/ min $147.00 240 ml $0.61 $0.09 $5.30 for cases longer than 2 mac hours, fgf for sevoflurane must be increased from 1 l/min to 2 l/min. in this example, sevoflurane is still slightly less expensive to administer than desflurane. vaa mac % fgf cost/bottle ml/bottle cost/ml cost/min cost/mac hr sevo 2% 2 l/min $ 93.93 250 ml $0.38 $0.08 $4.92 des 6% 0.5 l/min $ 147.00 240 ml $0.61 $0.09 $5.30 in florida, the cost of sevoflurane was $0.64/ml and the cost of desflurane was $0.55/ml (known to author). using dion’s formula, a comparison was made at lowest allowable fgf rates for cases less than 2 mac hours. for cases less than two mac hours, sevoflurane was less expensive to administer than desflurane at lowest allowable fgf rates. vaa mac % fgf cost/ bottle ml/bottle cost/ml cost/min cost/mac hr sevo 2% 1 l/min $ 159.50 250 $0.64 $0.07 $4.18 des 6% 0.5 l/min $ 133.00 240 $0.55 $0.08 $4.79 however, for cases longer than 2 mac hours, fgf for sevoflurane must be increased from 1 l/min to 2 l/min. in this case, sevoflurane was much more expensive to administer than desflurane. vaa mac % fgf cost/bottle ml/bottle cost/ml cost/min cost/mac hr sevo 2% 2 l/min $ 159.50 250 $0.64 $0.14 $8.35 des 6% 0.5 l/min $ 133.00 240 $0.55 $0.08 $4.79 in accordance with dion’s formula, nurse anesthetists are able to decrease cost of any vaa agent by using low fgf rates. advantages of low flow anesthesia desflurane and sevoflurane have low blood gas solubility coefficients that make them ideal for use with low flow anesthesia. through the use of these insoluble agents the anesthetist is able to maintain tight control of the anesthetic depth. the low aej solubility permits rapid changes in the depth of anesthesia and also provides a greater economy at low fgf rates.20 up to 90% of the administered dose of inhaled anesthetic escapes unused nto the atmosphere.21 low-flow anesthesia allows rebreathing, which conserves the amount of vaa used. low-flow anesthesia also conserves patient’s body temperature, maintains inspired humidity, and minimizes environmental pollution. the nurse anesthetist primarily controls the immediate cost of the inhaled agent through control of the fgf rate.21 disadvantages of low flow anesthesia anesthesia professionals may choose not to incorporate low fgf (low flow anesthesia) because of fears related to anesthetic complications. these fears may include difficulty controlling depth of anesthesia, accidental hypoxic events, hypercapnea, and the potential for toxic trace gases.21 an important disadvantage with the use of low flow anesthesia is the risk of hypoxia due to the dilution if inspired gases by exhaled oxygen depleted gases. higher delivered fio2 is required to off set the dilution of inspired gases by rebreathing. fears related to hypoxia and hypercapnea are mitigated with the use of gas analyzers and pulse oximetry. the newer vaas sevoflurane and desflurane have low blood gas solubilities which make them easier for anesthesia providers to titrate and maintain an adequate depth of anesthesia. with low flow anesthesia the anesthesia provider must remain vigilant and monitor the patient’s hemodynamics closely. low flow anesthesia is not recommended when gas must enter and leave a patient’s body quickly, as in induction and emergence. during induction it is common practice to induce with an intravenous agent such as propofol and then deliver a given percent of vaa throughout a case. consistent fgf and vaa delivery percent make calculation of cost easy. frequent variable fgf rates and delivered vaa percent make ongoing calculation more labor intensive and time consuming but possible. there’s an app for that! in order to simplify the cost calculation of a particular vaa use an iapp for cellular smart phones was developed. this iapp, the crna ivac, incorporates dion’s formula which accounts for gas behaviors expressed in the ideal gas law. the ideal gas law (universal gas law) expresses the relationship of pressure, volume, and temperature of a gas and is necessary when calculating the cost of any vaa. this cost calculation tool addresses the shortcoming of previous literature in which fgf rate were ignored or defaulted to the same fgf rate in calculations. the previous literature confuses the clinician as to the true cost of a particular vaa. the crna ivac incorporates the necessary factors to calculate the cost of a particular vaa anesthetic. direct comparison of one vaa to another is quickly and easily accomplished with this iapp. the crna ivac dispels misconceptions regarding the perceived cost of vaas and exemplifies the cost savings advantage of using low flow anesthesia. aej conclusion the primary clinical determinates of cost is actual delivery concentration of a particular vaa and the fgf rate. vaa percent delivered is dictated to a large extent by patient needs but fgf rate is fully adjustable by the nurse anesthetist. when considering all variables involved in vaa cost of use, fgf rate is the most easily manipulated and efficient cost savings factor available for nurse anesthetists. using the crna ivac the following generalities regarding vaa cost can be made: 1. isoflurane cost is inexpensive. 2. at 2l/min fgf rate for both agents, sevoflurane was consistently less expensive than desflurane. 3. generic offers cost savings compared to brand vaas. 4. low flow anesthesia (low fgf rate) for each agent maximizes cost savings for that particular agent. although improved outcomes have not been shown from low flow anesthesia, cost effectiveness remains a clinical achievement with this delivery technique. actual vaa cost is determined by actual consumption and the crna ivac quickly determines actual vaa cost. references 1 meyer t. managing inhaled anesthesia: challenges from a health-system pharmacist’s perspective. american journal of health-system pharmacy. 2010;67:s4-s8. 2 walker jr. what is new with inhaled anesthetics: part 1. journal of perianesthesia nursing. 1996;11(5):330-333. 3 odin i, feiss p. low flow and economics of inhalational anesthesia. balliere’s best practice in clinical anesthesiology. 2005;19:399-413. 4 boldt j, jaun n, kumle b, heck m, mund k. economic considerations of the use of anesthetics: a comparison of propofol, sevoflurane, desflurane, and isoflurane. anesthesia and analgesia. 1998;86:504-509. 5 cobos fv ii, haider h, barrera a, tinker j. computerized tracking and comparative cost analysis of sevoflurane and desflurane [abstract]. anesthesiology. 2007;107:a1108. http://www.asa-abstracts.com/strands/asaabstracts/abstract. htm;jsessionid=1efa35cffd03f53fdc6692bd1514 1cc6?year=2007&index=8&absnum=1748. accessed december 10, 2010. 6 traynor k. inhaled anesthetics present cost-saving opportunity. american journal of health-system pharmacy. 2009;66:606-607. 7 eger ei. cost in several flavors. international anesthesia research society. 2010;110(2):276-277. 8 eger ei. a brief history of the origin of minimum alveolar concentration (mac). anesthesiology. 2002;96(1):238-239. 9 eger ei, saidman lj, brandstate b. minimum alveolar anesthetic concentration: a standard of anesthetic potency. anesthesiology. 1965;26(6):756-763. 10 lockwood gg, white dc. measuring the costs of inhaled anaesthetics. british journal of anaesthesia. 2001;87(4):559-563. 11 weiskopf rb, eger ei. comparing the costs of inhaled anesthetics. anesthesiology. 1993;79(6):1413-1418. 12 puckett sd, andrews jj. sevoflurane use in veterans affairs medical centers: utility, safety, and cost-effectiveness. journal of the american association of nurse anesthetists. 1997;65(2):136-142. 13 dion p. the cost of anaesthetic vapors. canada journal of anaesthesia. 1992;39(6):633. 14 jellish ws, owen k, edelstein s, fluder e, leonetti jp. standard anesthetic technique for middle ear surgical procedures: a comparison of desflurane and sevoflurane. otolaryngology and head and neck surgery. 2005;133(2):269-274. aej 15 weinberg l, story d, nam j, mcnicols l. pharmacoeconomics of volatile inhalational anaesthetic agents: an 11-year retrospective analysis. anaesthesia and intensive care. 2010; 38(5)849-854. 16 golembiewski j. economic considerations in the use of inhaled anesthetic agents. american journal of healthsystem pharmacy. 2010;67:s9-s12. 17 chernin el. pharmacoeconomics of inhaled anesthetic agents: considerations for the pharmacist. american journal of health-system pharmacy. 2004;61(suppl 4):s18-s22. 18 lubarsky da, vigoda mm, wagner ds. economic and safety considerations of fast-acting inhaled anesthetics. formulary. 2007;42:1-6. 19 loke j, shearer waj. cost of anaesthesia. canada journal of anaesthesia. 1993;40(5):472-474. 20 ultane (sevoflurane) volatile liquid for inhalation. food and drug administration. from http://www.accessdata. fda.gov/drugsatfda_docs/label/2006/020478s016lbl.pdf. accessed 8/31/2012. 21 suttner s, boldt j. low-flow anaesthesia: does it have potential pharmacoeconomic consequences? pharmacoeconomics.2000;6:585-590. volume 5 no. 5 2017 educated hand publishing llc “the science behind the art” volume 5 no. 5 2017 anesthesia ejournal online issn 2333-2611 page 30 preoperative interventions for the prevention of hypothermia trish haley, ms(n), crna yejin min, ms(n), crna shawn collins, phd, dnp, crna vallire hooper, phd, rn, cpan, faan affiliation: trish haley ms(n) crna was a graduate student in the nurse anesthesia program at western carolina university, asheville, north carolina, at the time this paper was written. yejin min ms(n) crna was a graduate student in the nurse anesthesia program at western carolina university, asheville, north carolina, at the time this paper was written. shawn collins, phd, dnp, crna is a program director of the nurse anesthesia program at western carolina university school of nursing, asheville, north carolina. email: shawncollins@email.wcu.edu. vallire hooper, rn, phd, cpan, faan is the nursing research manager at mission healths, asheville, north carolina. funding/conflict of interest disclosure: none keywords: hypothermia, warming, preoperative, surgical population introduction perioperative hypothermia, defined by the american society of perianesthesia nurses (aspan), is a core temperature below 36 degrees celsius, and is known to increase the risk of surgical wound infections, poor wound healing, blood loss, prolonged and altered drug effects, increased duration of hospital stay, cardiac events, and morbidity and mortality.1,2 under normal physiologic conditions, the body can detect subtle drops in temperature. in response to a detected decrease in temperature, the hypothalamus will induce vasoconstriction and shivering mechanisms to maintain a core body temperature around 37 degrees celsius. the induction of anesthesia blunts this response from the hypothalamus and contributes to perioperative hypothermia by inhibiting the body’s natural mechanisms for heat regulation and redistribution of core body temperature to the periphery from the resulting vasodilation.1-3 anesthesia-induced redistribution of body heat is the process by which heat travels down a temperature gradient from warmer core tissues to cooler peripheral tissues. patients undergoing surgery are at high risk of hypothermia due to thermoregulatory mechanisms becoming dysfunctional after the induction of anesthesia and exposure to surgical procedures, cold fluids, and low ambient room temperatures.3 abstract perioperative hypothermia can be a significant issue for surgical patients. active warming methods initiated in the preoperative period may assist in the prevention of perioperative hypothermia. a literature review was conducted to provide a summary and resource for clinicians based on an evidence-based, practical, bedside approach to prewarming adult surgical populations and to highlight the further need for research. the literature review addressed preoperative warming recommendations, including warming methods and desired length of warming time. the literature supports the practice of preoperative warming for adult surgical patients to prevent or decrease the incidence of perioperative hypothermia. aej anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 5 2017 page 31 the current standard of care for avoiding perioperative hypothermia consists of intraoperative and postoperative warming interventions, both active and passive, yet the incidence of perioperative hypothermia remains a significant risk.2 one of the primary interventions used to prevent perioperative hypothermia is prewarming before the induction of anesthesia. hooper et al defined prewarming as the “warming of peripheral tissues or surface skin before induction of anesthesia.”1(p348) the literature suggests that preoperative warming with forced air reduces post-induction redistribution hypothermia, allows for faster rewarming after an initial post-induction drop in temperature intraoperatively, results in a higher average intraoperative temperature than non-prewarmed counterparts, and results in greater patient satisfaction.2,3 additional benefits patients may experience include decreased blood loss, reduced total anesthesia costs, decreased incidence of intensive care unit (icu) admission, reduction in myocardial infarctions, proper clotting, stable serum potassium levels, reduced need for postoperative mechanical ventilation, reduced incidence of surgical site infection, and an overall decrease in mortality.3 methods we used the pico question model to guide our search for current literature. the pico question is used to define the desired population (p), intervention (i), comparison (c), and outcome (o). the pico question used to guide this review was as follows: “in adults undergoing general anesthesia, does the addition of preoperative warming devices for a specific length of time compared to no preoperative warming methods result in a decreased incidence of perioperative hypothermia?” the authors independently performed electronic searches for published literature in the cumulative index to nursing and allied health literature (cinahl; ebsco), medline (national library of medicine), and cochrane central register of controlled trials (central; cochrane collaboration) databases using the ebsco search engine. the following keywords were used in varying combinations: “perioperative,” “peri-operative,” “preoperative,” “pre-operative,” “preoperative warming,” “hypothermia,” “warming methods,” “body temperature,” “forced-air warming,” “anesthesia,” “surgical,” and “active warming.” boolean operators were used in the search engine to filter and combine terms. included articles consisted of adult (18 years or older) surgical populations receiving general anesthesia for nonemergent surgery in which preoperative warming methods were studied. other inclusion criteria were the availability of the full text of the article, articles that underwent peer review, and articles that were written in or translated into english. articles published before january 2008 or after october 2015 were excluded. studies that included induced hypothermia were also excluded. the initial search resulted in 945 papers. after application of the inclusion and exclusion criteria previously defined and the removal of duplicate papers, 12 articles were identified for review. study quality was determined based on the grading of recommendations assessment, development, and evaluation (grade) system of review.4 review of literature table 1 is a concise presentation of the studies reviewed and presents authors, study design, journal publication and date, sample size, warming device used, and conclusions.5-16 table 2 lists study quality and limitations. three studies5-7 produced results showing a significant effect of preoperative warming with forced-air warming gowns (bair paws) compared to a control group. andrzejowski et al5 tested 68 adult surgical patients with 31 patients receiving 60 minutes of prewarming with the warming gown system prior to induction of anesthesia compared to the control group of 37 patients. the study was not blinded but this is unlikely to have affected the results. the sample size was small and the type of general anesthetic (sevoflurane or propofol) was not controlled. the study concluded that 60 minutes of prewarming with the forced-air warming gown resulted in a decrease in both intraoperative hypothermia and perioperative hypothermia. hooven6 reported that 11.7% of prewarmed patients were hypothermic on arrival to the post-anesthesia care unit compared to 48.6% of nonprewarmed patients (p=0.026). the study failed to record intraoperative patient temperatures or to control ambient surgical suite temperatures and also noted a significant (p=0.048) difference in mean surgical durations between the prewarmed group and the non-prewarmed group. kramer7 concluded that prewarming patients with a forced-air warming device was effective in reducing the amount of heat redistribution after the induction of anesthesia. unfortunately, this study was quite limited and lacked sufficient literature review. the sample size was small (n=24) and there were many limitations and lack of controls, including failure to control both the prewarming device temperature setting and the ambient temperature of the operating suite. different types of temperature devices were also used with no consistent timing of measurement. two studies used bair hugger forced-air warming blankets to provide preoperative warming. erdling and johansson8 studied 43 adult surgical patients and found that at 210 minutes after induction of anesthesia, esophageal temperatures in the prewarmed group increased by 0.65 degrees celsius with a standard deviation of 0.63 (p=0.001). the group that did not receive prewarming had esophageal temperature increases of 0.27 degrees celsius with a standard deviation of 0.62, but the increase was not statistically significant (p=0.052). it was concluded that 42 minutes of prewarming had a statistically significant effect (p=0.001) on preventing perioperative hypothermia. the authors noted the small sample size as a significant limitation. shin et al9 studied 72 adult surgical patients. the prewarmed group had significantly (p<0.001) higher core temperatures than did the non-prewarmed group at 20, 40, 60, 80, 100, and 120 minutes after induction and intubation. the incidence of perioperative hypothermia was significantly lower in the prewarmed group than in the non-prewarmed group at all time periods previously mentioned (p=0.007 at 20 minutes and p=0.001 at all other times). the study noted a limitation in the inconsistency of measurement devices used (tympanic or esophageal) and possible inaccuracy of the tympanic measurements due to interference with the warming device. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 5 2017 page 32 the mistral-air premium warming suit (passive warming) and mistral-air forced-air warming unit were studied by perl et al.10 a sample size of 90 adult surgical patients was divided into 3 groups. thirty-two patients received only standard preoperative insulation (cotton blankets). twenty-seven patients were warmed with the passive warming suit and 31 received the same passive preoperative warming combined with the forced-air warming device. a forced-air warming device with a reflective prewarming suit was significantly (p<0.05) effective in achieving higher core temperatures both intraoperatively and postoperatively compared to passive warming, which was shown to be ineffective at preventing perioperative hypothermia. intraoperative warming alone was ineffective in the prevention of perioperative hypothermia. prewarming durations varied greatly but all patients were warmed for at least 10 minutes. de witte et al11 looked at 27 adult surgical patients and prewarmed one group (n=9) with a forced-air warming device for 30 minutes and another group (n=9) with a carbon fiber warming device, also for 30 minutes. the control group consisted of 8 patients. after 30 minutes of prewarming with the carbon fiber device, patients had a core temperature that was significantly higher (p=0.05) than in the control group. there was no statistically significant difference between the forced-air and control groups. as seen with many of the available studies, the use of 2 methods to measure temperature (tympanic and esophageal) was noted as a limitation, as was the small population studied and inconsistent warmed body surface area. one study12 (n=200) focused on the duration of warming. preoperative patients undergoing general anesthesia with an expected surgical duration of 30 to 90 minutes compared a control group to 3 other groups receiving varying durations of active prewarming. fifty-two patients received 10 minutes of active warming. forty-three received 20 minutes of active warming. fifty received 30 minutes of active warming and 55 were considered the control group and received no active preoperative warming. the authors concluded that the risk of perioperative hypothermia was considerably reduced after prewarming with forced air for 10, 20, or 30 minutes in comparison to no preoperative active warming.12 no significant difference (p=0.54) was found between the 3 groups that received active warming, which suggested that at least 10 minutes of preoperative active warming is enough to affect the incidence of perioperative hypothermia.12 the search produced several studies with varying limitations. table 2 addresses the most significant recognized limitations and the quality of the studies based on the grade system of review. in contrast to other results, 4 trials found no statistical significance in relation to the addition of preoperative warming. rowley13 reported a sample size of 220 patients divided into 4 groups, each consisting of 55 individuals. the results showed no benefit of preoperative interventions compared to routine care (control group) in preventing perioperative hypothermia. the study compared forced-air warming in combination with routine care (cotton blanket) to routine care only. routine care, forcedair warming, and adjustment of the surgical suite temperature were combined as a study group as well as routine care and adjustment of surgical room temperature only. the study lacked randomization and failed to report p values clearly. the authors also noted a failure to achieve a temperature of 21.1 degrees celsius in some of the surgical suites during the cases studied.13 another study14 consisted of 128 subjects undergoing general anesthesia for a variety of surgical cases with no mention of case duration. the study compared only prewarmed patients to non-prewarmed patients. ambient surgical suite temperatures were not controlled for and the investigators failed to regulate the timing of temperature measurements. intraoperative temperature measurements were also not evaluated. the findings were not significant (p=0.314) for any difference in mean temperatures between the 2 groups.14 adriani et al15 is yet another study that found no significant difference with the addition of preoperative warming in preventing or lessening the incidence of perioperative hypothermia. adriani et al15 reported no significant difference (p=0.755) of body temperature over time between groups. study quality was low and had extensive limitations such as failure to control for operating room mattress temperature, ambient temperature, and the device used to measure patient’s temperature. no consistency was found in devices used for measurement (esophageal or oral), and many issues regarding intraoperative warming existed, including no criteria for initiation of intraoperative warming, failure to control ambient temperature, and surgical table underbody mattress that may or may not have been warmed.15 one additional study listed an inability to produce a lower rate of perioperative hypothermia with the addition of preoperative warming. the study had many flaws and limitations. the study was unable to effectively evaluate prewarming compared to non-prewarming interventions, which was its stated purpose.16 three of the 4 studies were of low quality due to varying levels of inconsistency, numerous limitations, small sample sizes, and inability to draw reliable conclusions. these studies were not considered for final recommendations concerning prewarming for the prevention of perioperative hypothermia. discussion under normal physiologic states, the body can maintain core temperatures between 36 and 37 degrees celsius. the 2 main areas of the brain responsible for regulating body temperature are the preoptic area and the anterior hypothalamus. these areas can trigger thermoregulatory responses when an increase or decrease in core temperature is detected by afferent sensing. vasodilation and sweating are induced to prevent hyperthermia, whereas vasoconstriction and shivering are induced to prevent hypothermia.17 the induction of general anesthesia creates a redistribution of body heat from core to periphery due to vasodilation and also blunts the response of the hypothalamus. without diligent warming, hypothermia is near unavoidable depending on numerous factors including room temperature, equipment used, type of procedure, length of procedure, and intravenous fluid temperature. over time, the anesthetized patient continues to lose heat and achieve a lower core body temperature. because anesthetic drugs hinder proper hypothalamic responses to hypothermia, the body is unable to induce vasoconstriction and shivering mechanisms for warming.17 once a patient’s core temperature becomes hypothermic, intraoperative active warming with forced-air devices likely will not be sufficient to restore normothermia due to the considerable amount of time it takes for the heat to reach the core tissues.1 because of this, it is important to incorporate interventions necessary to prevent or lessen the degree of hypothermia experienced after induction of anesthesia. of the studies reviewed, 8 of 12 reported prewarming to be effective in decreasing or preventing perioperative hypothermia. because 2 of the studies15,16 that found prewarming to be ineffective and 2 of the studies7,11 that found it to be effective were of poor quality, recommendations will be drawn from the remaining 8 studies. six of the remaining 8 studies concluded that preoperative warming was effective in varying durations ranging from 10 minutes to more than 60 minutes. forced-air warming devices, specifically bair paws gowns, were most consistently studied and shown to be effective with very minimal associated risks. conclusion the findings of this review suggest that adult surgical patients benefit from as little as 10 to 60 minutes of active prewarming to reduce perioperative hypothermia and that intraoperative warming alone is likely not adequate. because there are few risks involved in the addition of prewarming and the available literature suggests that it is effective, it is recommended as a standard of care for all adult surgical patients prior to the induction of general anesthesia. while 10 minutes of forced-air warming is an effective option that may reduce hypothermia in the perioperative period, it is likely that additional time may be more beneficial. there are an inadequate number of quality studies available to answer all of the questions surrounding preoperative warming interventions to prevent perioperative hypothermia. a need exists for randomized controlled trials testing current warming methods as well as newer technology. new studies should be consistent between groups and only use the most proven method of temperature measurement and reduce limitations. specific populations should also be further studied to identify those that may benefit from these interventions. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 5 2017 page 33 table 1. overview of the articles included in the literature review author, date, journal, design population, sample size (n) type of preoperative warming device, duration conclusions adriani & moriber (2013) aana journal quasi-experimental nonrandomized trial n=60 women undergoing general anesthesia for a variety of surgical types asa class i-iii bair paws, forced-air warming gown minimum of 30 minutes with a mean time of 51 minutes temperature controlled by patient active prewarming with bair paws gown demonstrated no significant effect on preventing perioperative hypothermia. body temperature over time showed no statistically significant difference between groups. andrzejowski et al (2008) british journal of anaesthesia randomized controlled trial n=68 adults undergoing general anesthesia for spinal surgery asa class i & ii bair paws, forced-air warming gown 60 minutes 60 minutes of prewarming with bair paws gown yielded a decrease in both intraoperative hypothermia and perioperative hypothermia. de witte et al (2010) anesthesia and analgesia randomized controlled trial n=27 adults undergoing general anesthesia for laparoscopic colorectal surgery forced-air warming carbon fiber warming 30 minutes 30 minutes of prewarming with resistive heating produced significantly higher core temperatures than in the control group. no significant difference between the forced-air and control group. erdling & johansson (2015) aana journal experimental randomized controlled trial n=43 adults undergoing general anesthesia in combination with regional analgesia for colorectal surgery asa class i&ii pre-warmed group: forced-air warming device warm touch, nellcor, or gaymar, smiths medic 32-52 minutes prewarming for 42 minutes had a positive effect in preventing perioperative hypothermia and even shorter prewarming times may be of benefit for hypothermia prevention. fettes et al (2013) aorn journal experimental randomized controlled trial n=128 adults undergoing general anesthesia for a variety of surgical cases asa class i-iii forced-air warming blanket approximately 60 minutes prewarming did not significantly affect patient temperature on arrival to the pacu or the length of time spent in the pacu. hooven (2011) journal of peri-anesthesia nursing quasi-experimental nonrandomized trial n=148 adults undergoing general anesthesia for colorectal surgery bair paws forced-air warming gown 60 minutes 11.7% of prewarmed patients were hypothermic compared with 48.6% of non-prewarmed patients (p=0.026). prewarming with the bair paws forced-air warming blanket decreased the incidence of perioperative hypothermia in patients undergoing colorectal surgery. horn et al (2012) anaesthesia experimental randomized controlled trial n=200 adults undergoing general anesthesia with a variety of surgical cases with expected durations of 30-90 minutes asa class i-ii snuggle warm upper body blanket, forced-air warming blanket covered by cotton blanket, connected to level 1 equator warmer 10, 20, or 30 minutes forced-air prewarming of 10, 20, or 30 minutes considerably decreased the incidence of perioperative hypothermia. there was no significant difference (p=0.540) between the 3 prewarmed groups. kramer (2013) journal of peri-anesthesia nursing quasi-experimental nonrandomized trial n=24 women undergoing general anesthesia for breast reconstruction forced-air warming gown minimum of 30 minutes forced-air prewarming gown was effective in decreasing post-induction redistribution hypothermia. nicholson (2013) aorn journal experimental randomized controlled trial n=66 adults undergoing general anesthesia for colorectal surgery asa class i-iv forced-air warming gown minimum 30 minutes prewarming with a forced-air warming gown was unable to decrease the number of patients who had perioperative hypothermia. perl et al (2014) minerva anestesiologica experimental prospective, randomized, multi-center, controlled study n=90 adults undergoing general anesthesia for a variety of surgical cases scheduled for 30-120 minutes asa class i-iii mistral-air premium warming suit (passive warming) mistral-air premium warming suit and mistral-air forced-air warming unit 30-60 minutes a forced-air warming device with a reflective prewarming suit was effective in achieving higher core temperatures both intraoperatively and postoperatively compared to passive warming, which was ineffective at preventing perioperative hypothermia. intraoperative warming alone was ineffective in preventing perioperative hypothermia. rowley et al (2015) clinical nursing research quasi-experimental nonrandomized trial n=220 adults undergoing general anesthesia for a variety of surgical procedures lasting a minimum of 60 minutes. forced-air warming blanket approximately 20-30 minutes no significant difference was found between preoperative to postoperative core body temperatures for each group. prewarming interventions were not more effective in preventing perioperative hypothermia. shin et al (2015) bmc anesthesiology experimental randomized controlled trial n=72 adults undergoing general anesthesia for endovascular coiling to treat cerebral aneurysm bair hugger, forced-air warming full-body blanket connected to warm-air-blower 30 minutes the prewarmed group had significantly higher core temperatures than those of the non-prewarmed group at 20, 40, 60, 80, 100, and 120 minutes post intubation (p<0.001). incidence of perioperative hypothermia was significantly lower in the prewarmed group than in the nonprewarmed group at 20, 40, 60, 80, 100, and 120 minutes after intubation (p=0.002 at 20 min, p<0.001 at other times). conclusion: prewarming should be considered as part of the anesthetic management for patients undergoing coiling of aneurysm at risk of hypothermia in a cold environment. abbreviations: asa, american society of anesthesiologists; pacu, post-anesthesia care unit. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 5 2017 page 34 table 2. article limitations author, date, journal, design quality limitations adriani & moriber (2013) aana journal quasi-experimental nonrandomized trial strength: level 2 quality: low oral and esophageal probe was used to obtain temperature readings extraneous variables not controlled: ambient temperature, or mattress temperature, and staff taking temperature readings non-blinded, nonrandomized, small sample size andrzejowski et al (2008) british journal of anaesthesia randomized controlled trial strength: level 1 quality: moderate not all patients had same method of anesthesia maintenance non-blinded actual mean duration of prewarming longer than the target of 60 minutes de witte et al (2010) anesthesia and analgesia randomized controlled trial strength: level 2 quality: low small population studied warmed body surface area inconsistent between forced-air group and carbon fiber group duration of anesthesia 90-260 minutes 2 methods were used to measure core temperature: tympanic and esophageal probe clinical setting was inappropriate to study heat balance and the quantification of redistribution of heat erdling & johansson (2015) aana journal experimental randomized controlled trial strength: level 1 quality: high limitations in sample size, type of surgery, and anesthesia technique limiting generalizability beta-blockers and vasopressor medications were used in both prewarmed and non-prewarmed group during anesthesia patient conditions such as perfusion and tissue disorders may have affected results varied placement of temperature probes in patients outflow temperature in the warming device varied from -1°c to +5°c from the preset value of 43°c fettes et al (2013) aorn journal experimental randomized controlled trial strength: level 1 quality: moderate small sample size both groups received warmed cotton blankets preoperatively lack of patients with hypothermia in both groups throughout the study intraoperative temperature measurements were not evaluated imprecise time intervals for temperature measurements hooven (2011) journal of peri-anesthesia nursing quasi-experimental nonrandomized trial strength: level 2 quality: moderate temperature measurements only obtained for preoperative and postoperative periods mean surgical duration time differed significantly between the 2 groups (p=0.048) significant difference in preoperative temperatures in both groups (p=0.008) temperature measurement intervals unclear and staff training on correct equipment use unclear horn et al (2012) anaesthesia experimental randomized controlled trial strength: level 1 quality: high distribution of surgery types was not equal among groups 4% of patients were already hypothermic on arrival to preoperative unit patients not blinded kramer (2013) journal of peri-anesthesia nursing quasi-experimental nonrandomized trial strength: level 2 quality: low nonrandomized oral and esophageal temperature measurement instruments used in the study not clear on prewarming device set temperature, ambient or room temperature, correct use of temperature measurement instruments and other equipment nicholson (2013) aorn journal experimental randomized controlled trial strength: level 1 quality: low both study groups received prewarming before induction of general anesthesia few participants were hypothermic on arrival to preoperative area; no mention of distribution in the study groups no mention of prewarming device temperature and staff training on equipment use various temperature measurement instruments used throughout the study: oral, nasal, esophageal, or rectal temperature probe or temperature-sensing urinary catheter lack of dedicated research assistants or co-investigators, the facility policy to warm patients intraoperatively before induction, and difficulty obtaining oral temperatures in the immediate postoperative period perl et al (2014) minerva anestesiologica experimental prospective, randomized, multi-center, controlled study strength: level 1 quality: moderate 22 patients had to be excluded due to protocol violations a wide range of prewarming durations (but all patients received greater than 10 minutes of prewarming) a relevant number of patients were hypothermic on arrival to the or no mention of prewarming device temperature or staff training on equipment use oral and esophageal probe used for temperature measurement in the study rowley et al (2014) clinical nursing research quasi-experimental nonrandomized trial strength: level 2 quality: high no randomization (convenience sample) unable to achieve desired ambient surgical room temperature of 21.1°c/70°f for some study cases in samples iii and iv ebl not included in the data collection many surgical candidates excluded from the study due to obesity and comorbidities shin et al (2015) bmc anesthesiology experimental randomized controlled trial strength: level 1 quality: high oral and esophageal probe used for temperature measurement in the study warming device indirectly affected tympanic membrane temperature and caused inaccuracy of core temperature measurement with the infrared tympanic thermometer, so the highest value of 3 consecutive measurements were recorded to decrease error and the study relied more heavily on the esophageal temperature as the accurate measurement of core temperature no mention of prewarming device temperature and staff training on equipment use abbreviations: ebl, estimated blood loss; or, operating room. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 5 2017 page 35 references 1. hooper v, chard r, clifford t, et al. aspan’s evidence-based clinical practice guideline for the promotion of perioperative normothermia: second edition. j perianesth nurs. 2010;25(6):346-365. 2. de brito poveda v, clark am, galvão cm. a systematic review on the effectiveness of 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perianesth nurs. 2013;28(3):e51. https://doi. org/10.1016/j.jopan.2013.04.144. 8. erdling a, johansson a. core temperature—the intraoperative difference between esophageal versus nasopharyngeal temperatures and the impact of prewarming, age, and weight: a randomized clinical trial. aana j. 2015;83(2):99-105. 9. shin km, ahn jh, kim is, et al. the efficacy of pre-warming on reducing intraprocedural hypothermia in endovascular coiling of cerebral aneurysms. bmc anesthesiol. 2015;15(1):8. https://doi.org/10.1186/1471-2253-15-8. 10. perl t, peichl lh, reyntjens k, deblaere i, zaballos jm, bräuer a. efficacy of a novel prewarming system in the prevention of perioperative hypothermia. a prospective, randomized, multicenter study. minerva anestesiol. 2014;80(4):436-443. 11. de witte jl, demeyer c, vandemaele e. resistive-heating or forced-air warming for the prevention of redistribution hypothermia. anesth analg. 2010;110(3):829-833. https://doi.org/10.1213/ane.0b013e3181cb3ebf. 12. horn ep, bein b, böhm r, steinfath m, sahili n, höcker j. the effect of short time periods of pre-operative warming in the prevention of peri-operative hypothermia. anaesthesia. 2012;67(6):612-617. https://doi.org/10.1111/j.13652044.2012.07073.x. 13. rowley b, kerr m, van poperin j, everett c, stommel m, lehto rh. perioperative warming in surgical patients: a comparison of interventions. clin nurs res. 2015;24(4):432-441. https://doi.org/10.1177/1054773814535428. 14. fettes s, mulvaine m, van doren e. effect of preoperative forced-air warming on postoperative temperature and postanesthesia care unit length of stay. aorn j. 2013;97(3):323-328. https://doi.org/10.1016/j.aorn.2012.12.011. 15. adriani mb, moriber n. preoperative forced-air warming combined with intraoperative warming versus intraoperative warming alone in the prevention of hypothermia during gynecologic surgery. aana j. 2013;81(6):446-451. 16. nicholson m. a comparison of warming interventions on the temperatures of inpatients undergoing colorectal surgery. aorn j. 2013;97(3):310-322. https://doi.org/10.1016/j.aorn.2012.12.018. 17. díaz m, becker de. thermoregulation: physiological and clinical considerations during sedation and general anesthesia. anesth prog. 2010;57(1):25-33. https://doi.org/10.2344/0003-3006-57.1.25. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 5 2017 page 36 https://doi.org/10.1111/j.1365-2702.2012.04287.x https://doi.org/10.1093/bja/aen272 https://doi.org/10.1016/j.jopan.2010.07.013 https://doi.org/10.1016/j.jopan.2013.04.144 https://doi.org/10.1016/j.jopan.2013.04.144 https://doi.org/10.1186/1471-2253-15-8 https://doi.org/10.1213/ane.0b013e3181cb3ebf https://doi.org/10.1111/j.1365-2044.2012.07073.x https://doi.org/10.1111/j.1365-2044.2012.07073.x https://doi.org/10.1177/1054773814535428 https://doi.org/10.1016/j.aorn.2012.12.011 https://doi.org/10.1016/j.aorn.2012.12.018 https://doi.org/10.2344/0003-3006-57.1.25 anesthesia ejournal volume 2 issue 1 2014 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 popular press coverage has noted that generational diversity exists in the workplace, suggesting strategies for generational harmony and improving job satisfaction. however, little empirical evidence has linked job satisfaction to generational profiles. the current nurse anesthesia workforce includes three predominant generations: baby boomers, generation x, and generation y. a quantitative descriptive design was used to compare job satisfaction between generational cohorts of crnas in michigan. four hundred and seven respondents completed an online survey (the nursing work index – revised) as a measure of job satisfaction. results indicated that overall, nurse anesthetists have a relatively high job satisfaction across generations. crna job satisfaction scores were impacted by their sense of autonomy, their ability to work with clinically competent peers, working for employers who provide opportunity for advancement and education, and having leadership representation at high administrative levels. anova revealed no significant differences in job satisfaction scores between the three generations. information from this study has implications for surgical teams, patients, hospital administrators, nurse anesthesia leaders and individual crnas. understanding factors that influence crna job satisfaction can enhance the work environment and prove to be beneficial to all generations of crnas. keywords: generation, job satisfaction, values, crna abstract job satisfaction among certified registered nurse anesthetists: a multigenerational analysis lisa mileto crna, dnp barbara penprase rn, phd, cnor author correspondence: lisa mileto crna, dnp lmileto3@gmail.com barbara penprase rn, phd cnor penprase@oakland.edu a generational transformation is occurring in healthcare across america. for the first time in history, the workforce consists of three generations working together.1 exploring certified registered nurse anesthetist (crna) job satisfaction from a generational perspective could encourage leaders to capitalize on unique, generationspecific opportunities to recruit and retain highly qualified crnas, maximize departmental effectiveness and communication, and create favorable employment arrangements. understanding generational differences may diffuse intergenerational conflicts that can emerge when values are not aligned. a national dialogue is developing amongst generation experts, researchers, and leaders suggesting that generational needs be taken into account to improve job satisfaction, particularly in nursing.2-5 the purpose of this study was to determine if there is a difference in job satisfaction among crnas from three different generations. the factors influencing crna job satisfaction that were examined in this study are central concepts in the nursing work index revised (nwi-r) survey, including autonomy, control over practice setting, nurse-physician relationships, and organizational support.6 table 1 defines these factors. mailto:lmileto3@gmail.com mailto:penprase@oakland.edu anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 1 2014 background each generation has innate core values influenced by the era in which they were born and experiences in their life span.3,7 strauss and howe’s7 generational theory was used to guide this research. this sociological theory examines the things that drive people’s behavior. a generation is a cohort group who share birth years and are deeply influenced by and bound together by their experiences.3 the events people experience throughout their formative years partly determine who they are, how they see the world, and what they value. events that capture the attention and emotions of millions of people throughout their youth contribute to the development of a generational personality.7 table 2 is a demographic overview of three generations. the baby boomers (born between 1946-1964) grew up in a time of economic expansion and prosperity, significant social movements, and national optimism.7 defining events that occurred during the baby boomers’ formative years included the cold war, elvis presley and the beatles, the vietnam war, and the civil rights movement. they were empowered by protests, an emerging drug culture, and sexual and spiritual evaluation. 3,7,8 rosa parks, assassinations of martin luther king and john f. kennedy, and woodstock all left an indelible mark.3,7,8,9 today, baby boomers are concerned about their workplace environment and they value participation, fairness, and equality. boomers are team players that believe in inclusion and collaboration.8,9 additionally, they are fiercely competitive and go to great lengths to get what they want.3 table 3 lists the core values of baby boomers.9 during their formative years, generation x (born between 1965-1977) witnessed corporate layoffs and corruption, inflation, the energy crisis, and nuclear proliferation.8 rapidly rising divorce rates and women entering the workforce changed family dynamics. these defining events contributed to generation x developing a prevailing skepticism.8 institutions that were previously stable began to fail, leading to distrust, disappointment, and a survivor mentality.3 watergate, the fall of the berlin wall, the challenger disaster, and operation desert storm were all sentinel events that influenced generation x.8 today, generation x value balance in their lives, particularly between their work and personal lives; they do not define themselves by their work.9 they are frugal and are not influenced by trendy brand names or hype.9 having little regard for corporate life, they often challenge or work around authority and the status quo.9 they are independent problem solvers who excel at multitasking and using technology.3 table 3 lists the core values of generation x.9 defining events in the formative years for generation y (born between 1978-2000) included threats and acts of terrorism, including september 11th, 2001, the turning of a new century, the bombings in oklahoma city, and school shootings.10 this cohort was raised in a child-focused environment.10 parents were involved in their children’s lives in a style of parenting coined “helicopter parenting”, creating an environment of protection and guidance. generation y has received extensive accolades for their achievements and have been the recipients of a cultural shift toward the promotion of positive self-esteem.11 generation y is often referred to as the narcissistic generation. a study of 16,475 college students between 1982 and 2006 revealed that narcissism has steadily increased since 1982.12 the narcissistic personality inventory results indicated that by 2006, two-thirds of the students had above-average scores on this inventory, ranking 30% higher than students in 1982.12 current social media such as facebook, twitter, vine, instagram, and youtube encourage self-promotion. generation y’s sense of entitlement is fed by their baby boomer parents, who spend billions of dollars each year on their children.12 in contrast to baby boomers, generation y values changing employment frequently to seek the work environment that meets their personal needs and desired lifestyle.8,11 in addition to having a sense of civic responsibility and social engagement, they are tech-savvy as well as tech-dependent.11 table 3 lists generation y’s core values.9 generational theory creates a powerful framework for examining the practice environment and job satisfaction of nurse anesthetists through exploration of core values, expectations, attitudes, and behaviors. limited current research exists specifically related to job satisfaction of crnas, particularly in the united states. work environment characteristics and personality dimensions among dutch nurse anesthetists were examined in relation to burnout, job satisfaction, and turnover intention. results revealed that 42% intend to leave their job within 2 years.13 exploration of job satisfaction, emotional wellbeing, and working conditions of austrian and swiss anesthetists indicated that high levels of job satisfaction exist in anesthetists who found their work interesting and had opportunities to contribute skills and ideas to the workplace.14 jones and fitzpatrick15 conducted a descriptive study examining attitudes toward collaboration, surveying crnas and anesthesiologists in texas. crnas consistently had higher mean scores than anesthesiologists in the four subscales examined: shared education and teamwork, caring opposed to curing, crna autonomy, and physician authority.15 research involving factors that influence job satisfaction as it relates to generational differences is relatively recent. wieck et al6 completed a generational assessment of job satisfaction, work environment, and favorable manager characteristics. nurses’ satisfaction was measured using the nurse work index-revised.16 surveying 1,773 staff registered nurses (rns) from 22 hospitals, they found that generation y nurses were least satisfied with organizational support and their control over practice. generation x nurses were least satisfied with control over practice and autonomy. baby boomers had the lowest satisfaction scores in the areas of control of practice and satisfaction with the work environment, but the highest overall satisfaction scores. additional recent studies demonstrate significant diversity in job satisfaction and work values among generations, particularly in the areas of burnout, empowerment, value congruence, workplace cohesion, supervisor support, and organizational commitment.17,18,19 a survey of nurses and their experiences of distress and collegiality at work was conducted by leiter et al.20 the aim of the study was to determine if generational differences exist between these experiences. generation x nurses reported more negative experiences than baby boomers on all measures including incivility, cynicism, physical symptoms, exhaustion, and turnover intent. wilson et al21 conducted a study to explore how overall job satisfaction and satisfaction with specific aspects of work are anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 1 2014 similar and different across generations of nurses (n = 6,541). results indicated that generation x and y had a significantly lower level of job satisfaction as compared with baby boomers. baby boomers were significantly more satisfied with rewards such as pay and benefits. baby boomers also reported higher levels of satisfaction with professional opportunities, praise, and recognition as compared to generation x. generation x placed a higher value on self-directed recognition and professional opportunities and relied less on organizations. there were no differences in generational cohorts in satisfaction with nursing co-workers or other health care provider interactions. methodology for this study, a quantitative descriptive design was used to compare job satisfaction between generational cohorts of crnas. the target population for this study consisted of 2,163 practicing crnas throughout michigan who were, at the time of survey mailing, active members of the michigan association of nurse anesthetists (mana). crnas born between 1946 and 1989 were included in data analysis and categorized according to generational cohort. birth year was used to categorize the participants into generational cohorts: baby boomers, born between 1946-1964; generation x, born between 1965 and 1977; and generation y, born between 1978 and 2000. for the purpose of data analysis, 1989 served as the cut-off for placement in the generation y cohort because it is unlikely that anyone born after 1989 would have achieved the educational preparation to be a crna. permission to use human subjects was obtained from the oakland university investigational review board prior to data collection. mana distributed the e-mail to all crna members, which included the informed consent with a link to the demographic questionnaire and the nursing work index – revised (nwi-r). completion of the survey indicated implied consent. the nwi-r instrument was used to measure crna job satisfaction from three different generational cohorts. the nwi-r has been used successfully to assess nursing job satisfaction in a number of published studies over several decades, has proven sound psychometric properties, and has good to excellent reliability.16,22,23,24 content validity of the instrument has been documented in multiple studies that have demonstrated the identification of work environment characteristics supportive of professional nursing practice.16,22,23,24 the nwi-r was slightly modified by minor language changes to fit crna practice. for example, the word “nurse” was changed to “crna” and the items “the use of written nursing care plans”, “working on highly specialized units”, “floating to different units”, and “caring for the same patient from one day to the next” were eliminated. this was done to allow for optimal answers about the individual’s work environment. results the electronic survey was opened by 450 crnas. in total, 43 cases were eliminated due to either the participant completing only the demographic questions and not the survey or the participant was born before 1946. this left 407 respondents (90.4%). the mean age was 47 (sd = 10) with a minimum age of 26 and a maximum of 66. baby boomers comprised 53.6% of the sample (n=218), generation x comprised 31.2% (n=127), and generation y comprised 15.2% (n=62). additional demographic data is presented in table 4. the survey used 38 items and a 4-point likert scale, asking participants to respond by indicating the extent to which they agree that each item is present in their current job, with 1 (strongly disagree), 2 (somewhat disagree), 3 (somewhat agree), and 4 (strongly agree); the higher the score, the higher the job satisfaction. the mean job satisfaction score was 2.89 (range = 1.50 to 3.92, se = .04). the distribution had mild deviations from normality (skewness = -.13; kurtosis = .34) indicating that the largest portion of the data was above the mean (median = 2.87) with slight leptokurtosis. therefore, it was determined that parametric statistical analysis using anova was appropriate. the lowest mean score for baby boomers (2.24, sd = 0.86) was on the item “there is opportunity for advancement”. the lowest mean for generation x (2.25, sd = 0.93) was on the item “department educators provide patient care consultation”, and the lowest mean for generation y (2.27, sd = 0.99) was on the item “a chief nurse executive or anesthesia leader is equal in power and authority to other top-level executives”. the highest mean for the baby boomers (3.64, sd = 0.55), generation x (3.65, sd = 0.48) and generation y (3.72, sd = 0.49) was on the item “working with crnas who are clinically competent”, thus being the highest overall mean for all respondents (3.66, sd = 0.52). table 5 lists the overall highest and lowest means of all respondents for specific items. the mean job satisfaction scores for each generation were: baby boomers, 2.90 (sd = 0.62); generation x, 2.82 (sd = 0.47); and generation y, 3.01 (sd = 0.48). the four subscale means for all respondents were: autonomy 2.80 (se = 0.04), organizational support 2.93 (se = 0.03), control over practice 3.03 (se = 0.04), and crna/physician relationships 3.03 (se = 0.03). analysis of variance (anova) was used to compare the means of overall job satisfaction scores between generations and subcategories of job satisfaction between generations. results indicated no difference in job satisfaction scores between generations f(2, 200) =1.524, p = .22. in addition to testing the mean job satisfaction score, the data were analyzed according to the nwi-r four subscales: autonomy, control over practice, organizational support, and crna/physician relationships. mean scores were created for subscales in the same manner as the overall job satisfaction score. anovas were run separately for each subscale to see if any generational differences might exist for any of the subscales. no significant differences were found on any of the subscale: autonomy f(2, 339)=.865, p=.42; control over practice f(2, 351)=2.044, p=.13; organizational support f(2, 337)=.968, p=.38; and crna/physician relationships f(2, 386)=0.591, p=.55. discussion the findings revealed no significant difference in job satisfaction scores between three generations of crnas. there were, however, several interesting findings that warrant comment and further investigation. the american association of nurse anesthetists (aana) demographic data align closely with the descriptive data in this study (table 8). according to a recent aana member survey data report,25 the average age of anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 1 2014 crnas in the united states is 50; the average age of crnas in this study was 47. a surprisingly large percentage of crnas have been in practice for over 20 years. many are eligible for retirement in the next 5 years, yet are not planning to retire.25 are crnas choosing to postpone retirement due to recent economics changes, overall job satisfaction, or other factors? are there generational implications of these findings? this study reports a total job satisfaction mean of 2.89 (on a 4 point scale), indicating crna respondents were somewhat satisfied with their job. based on generational and subscale mean job satisfaction scores, crnas are somewhat satisfied with their job. this result aligns with the aana member survey data report.25 the aana used a 5-point likert scale ranging from 1 (not favorable) to 5 (very favorable). the survey asked “how favorable is your primary work environment to crnas?” the mean was 3.9, with 72% responding 4 or 5 (n = 5,704). the aana survey also asked “how satisfied are you with a career as a nurse anesthetist?” the mean response was 4.4, with 89% responding 4 or 5 on a scale of 1, (not satisfied) to 5 (very satisfied). the highest item mean impacting job satisfaction for all three generations in this study related to working with highly competent crnas. the lower mean item scores for job satisfaction found in this study included opportunities for advancement, educational needs of crnas, and crnas perceptions of the importance of administrative representation. this is valuable information for examining crna job satisfaction. these factors indicate the potential need for improved educational offerings for crnas at the workplace, having crna leadership that has influence with administration, and providing crnas with opportunities for advancement. the subgroup of autonomy had the lowest overall mean for all respondents. items in this subgroup included: “not being placed in a position to do things that are against my judgment”, “freedom to make important patient care and work decisions”, “a supervisory staff that is supportive of crnas”, and “an anesthesia manager backs up crnas in decision making, even if the conflict is with a physician”. the results of lower job satisfaction related to lack of autonomy parallel results reported in earlier studies.4, 6,15 similarly, the aana survey indicated that 21% of crnas reported a lack of job autonomy as an issue affecting their practice.25 the demographics of nurse anesthesia are rapidly changing.25 nurse anesthesia educational programs have increased in number and enrollment over the past 10 years. according to the aana practice profile and demographic surveys and database,26 in 1999 there were 2,472 students enrolled in nurse anesthesia programs, and in 2009 there were 5,490 students enrolled. this is a 122% increase in anesthesia student enrollment. will the demographics abruptly shift in the next 10 years and impact crna job satisfaction? will greater generational diversity in nurse anesthesia impact job satisfaction in the future? exploring these questions empirically will be beneficial for the profession. this study was limited to crnas who were mana members practicing in michigan, thus the findings cannot be generalized beyond this population. a type ii error may have occurred in this study due to a small sample size or small differences in measured effect between groups due to lack of precision in the instrument. power analysis was not performed. generational theory has been criticized for creating generalizations about groups of people based on anecdotal evidence, age, and demographic data. there may be an imbalance of extrapolated information that has grouped people into generations versus empirical evidence of generational differences.27 alternatively, generational difference is a relatively new field of study with empirical and theoretical growth on the rise, making it an excellent area for study. regarding the nwi-r, the statement that was most frequently answered as ‘not applicable’ or left blank was “department educators provide patient care consultation” (n = 75 blank), followed by “a preceptor program exists for new employees” (n = 59 blank or “not applicable”), followed by “crnas are supported in pursuing advanced degrees” (n = 56 blank). possible reasons for incomplete responses include confusion about the statement, or the respondent felt something in the statement was not applicable to him or herself or their work environment, or other unknown reasons. nurse anesthetists are advanced practice nurses that form a unique subset of nursing. this calls into question the validity of the nwi-r for use in nurse anesthesia. even the minor modifications made to this tool could have a negative impact on reliability and validity. ideally, a reliable and valid job satisfaction survey should be created that is specific to nurse anesthetists. despite the limitations, this research provides important and unique insight into the job satisfaction of nurse anesthetists. overall, nurse anesthetists have a relatively high job satisfaction across age ranges. crna job satisfaction is impacted by their sense of autonomy, opportunity for advancement, educational opportunities offered by their employer, and leadership representation at high administrative levels. although not generationally specific, these concepts crossed all generations. nurse anesthesia leaders can improve job satisfaction by modifying organizational practices to meet the workplace needs and values of crnas. mainstream publications contain recommendations for generational management styles; general discussion about generational differences in the work place occurs regularly. people bring their life experience and values to work. although this research did not find a significant difference between generations and job satisfaction among crnas, the negligible differences this study revealed may have practical interest and value for nurse anesthetists, and the data present interesting questions for further research. nurse anesthetists should continue to explore factors that influence crna job satisfaction and develop strategies aimed at maintenance and improvement of the workplace environment. anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 1 2014 references 1. swenson c. next generation workforce. nurs econ. 2008;26(1):64-65. 2. lavoie-tremblay m, o’brien-pallas l, gélinas c, desforges n, marchionni c. addressing the turnover issue among new nurses from a generational viewpoint. j nurs manag. 2008;16(6):724-733. 3. martin ca, tulgan b. managing the generation mix: from collision to collaboration (manager’s pocket guide series). 2nd ed. amherst, ma: hrd press; 2006. 4. zangaro ga, soeken kl. a meta-analysis of studies of nurses’ job satisfaction. res nurs health. 2007;30(4):445458. 5. shacklock k, brunetto y. the intention to continue nursing: work variables affecting three nurse generations in australia. j adv nurs. 2012;68(1):36-46. 6. wieck kl, dols j, landrum p. retention priorities for the intergenerational nurse workforce. nurs forum. 2010;45(1):7-17. 7. strauss w, howe n. generations: the history of america’s future, 1584 to 2069. new york, ny: william morrow; 1991. 8. lancaster lc, stillman d. when generations collide. harpercollins: new york; 2002. 9. zemke r, raines c, filipczak r. generations at work: managing the clash of veterans, boomers, xers, and nexters in your workplace. new york, ny: amacom; 2000. 10. huntley r. the world according to y: inside the new adult generation. crows nest, australia: allen & unwin; 2006. 11. twenge jm, campbell k. the narcissism epidemic: living in the age of entitlement. new york, ny: free press; 2009. 12. twenge jm. generation me: why today’s young americans are more confident, assertive, entitled – and more miserable than ever before. new york, ny: free press; 2006. 13. meeusen vc, van dam k, brown-mahoney c, van zundert aa, knape ht. understanding nurse anesthetists’ intention to leave their job: how burnout and job satisfaction mediate the impact of personality and workplace characteristics. health care manage rev. 2011;36(2):155-163. 14. kinzl jf, knotzer h, traweger c, et al. influence of working conditions on job satisfaction in anesthetists. br j anaesth. 2005;94(2):211-215. 15. jones ts, fitzpatrick jj. crna-physician collaboration in anesthesia. aana j. 2009;77(6):431-436. 16. aiken l, patrician p. measuring organizational traits of hospitals: the revised nursing work index. nurs res. 2000;49(3):146-153. 17. sparks am. psychological empowerment and job satisfaction between baby boomers and generation x nurses. j nurs manag. 2012;20:451-460. 18. leiter m, jackson n, shaughnessy k. contrasting burnout, turnover intention, control, value congruence and knowledge sharing between baby boomers and generation x. j nurs manag. 2009;17(1):100-109. 19. keepnews d, brewer c, kovner c, shin j. generational differences among newly licensed registered nurses. nurs outlook. 2010;58(3):155-163. 20. leiter m, price s, spence laschinger h. generational differences in distress, attitudes and incivility among nurses. j nurs manag. 2010;18(8):970-980. 21. wilson b, squires m, widger k, cranley l, tourangeau a. job satisfaction among a multigenerational nursing workforce. j nurs manag. 2008;16(6):716-723. 22. krebs j, madigan e, tullai-mcguinness s. the rural nurse work environment and structural empowerment. policy polit nurs pract. 2008;9(1):28-39. 23. lake e. development of the practice environment scale of the nursing work index. res nurs health. 2002;25(3):176-188. 24. lake e. the nursing practice environment: measurement and evidence. med care res rev. 2007;64(2 suppl):104s122s. 25. american association of nurse anesthetists. member survey data report. available at: http://www.aana.com/ myaana/aanabusiness/aanasurveys/documents/aanamember-survey-data-nov2011.pdf. accessed jan. 15, 2013. 26. american association of nurse anesthetists. aana practice profile and demographic surveys and database. park ridge, il: aana; 2010. 27. hanson jc, leuty me. work values across generations. j career assess. 2012;20(1):34-52. file:///users/sheriharvey/desktop/customers/anesthesia%20journal/generational%20study-mileto%20v.2-i.1/../appdata/local/microsoft/windows/temporary internet files/content.ie5/appdata/local/microsoft/windows/temporary internet files/content.ie5/appdata/local/microsoft/windows/temporary internet files/content.ie5/4afrk31d/available at: www.aana.com/myaana/aanabusiness/aanasurveys/documents/aana-member-survey-data-nov2011.pdf file:///users/sheriharvey/desktop/customers/anesthesia%20journal/generational%20study-mileto%20v.2-i.1/../appdata/local/microsoft/windows/temporary internet files/content.ie5/appdata/local/microsoft/windows/temporary internet files/content.ie5/appdata/local/microsoft/windows/temporary internet files/content.ie5/4afrk31d/available at: www.aana.com/myaana/aanabusiness/aanasurveys/documents/aana-member-survey-data-nov2011.pdf file:///users/sheriharvey/desktop/customers/anesthesia%20journal/generational%20study-mileto%20v.2-i.1/../appdata/local/microsoft/windows/temporary internet files/content.ie5/appdata/local/microsoft/windows/temporary internet files/content.ie5/appdata/local/microsoft/windows/temporary internet files/content.ie5/4afrk31d/available at: www.aana.com/myaana/aanabusiness/aanasurveys/documents/aana-member-survey-data-nov2011.pdf table 1 factors influencing crna job satisfaction autonomy: the freedom to make independent decisions in crna practice that are in the best interest of the patient. control over the practice setting: organizational autonomy or the freedom to take the initiative in shaping anesthesia departmental and institutional policies for patient care. nurse-physician relationships: involvement and connection between crna and physician regarding patient care. organizational support: administrative and managerial support for crnas, including opportunities for continuing education, advancement, and adequacy of resources. crna, certified registered nurse anesthetist. source: nurse work index-revised survey.5 table 2 comparison of three generations3 generation birth years current age population baby boomer 1946-1964 50-68 80 million generation x 1965-1977 37-49 46 million generation y 1978-2000 36 -14 76 million table 3 characteristics of generations baby boomer main values • optimism • teamwork • personal gratification • health/wellness • personal growth • work anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 1 2014 anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 1 2014 table 4 comparison of demographic data mana crna surveya and aana crna surveyb variable mana survey (n = 407) aana survey (n = 7,053 mean age 47 50 age cohort 48 66: 54% 36 47: 31% <35: 15% over 49: 55% 35 49: 35% <34: 10% years experience over 20 10 to 20 less than 10 34% 28% 38% 35% 23% 42% gender female 61% 58% male 39% 42% practice setting hospital 89% 87% asc 10% 11% other 1% 2% role staff crna 90% 96% administration 6% 2% education 3% 2% anwi-r electronic survey of michigan crnas bamerican association of nurse anesthetists, member survey data report table 5 high and low mean job satisfaction scores – nwi-r item mean, sda mean, sda high scores working with competent peers 3.66, 0.52 high standard of care expected 3.60, 0.66 satisfactory salary 3.33, 0.77 low scores opportunity for advancement 2.28, 0.85 anesthesia leader equal in power to executives 2.31, 1.02 educators provide consultation 2.36, 0.93 astandard deviation anesthesia ejournal volume 3 issue 2 2015 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 postoperative residual neuromuscular blockade continues to affect a considerable percentage of patients admitted to the post-anesthesia care unit. research supports the use of quantitative acceleromyography to monitor neuromuscular blockade and recovery. the purpose of this report was to determine whether objective acceleromyography compared with subjective peripheral twitch monitors and clinical assessment is more effective in decreasing the occurrence of postoperative residual neuromuscular blockade. a literature search was conducted by using clinicalkey, the cochrane collaboration, embase, pubmed, and proquest. a total of 36 articles met the inclusion criteria, of which 8 were included in the present review. the evidence is consistent in portraying that the use of acceleromyography does decrease the occurrence of residual neuromuscular blockade and it does prevent patients from being reversed at much lower trainof-four ratios. residual neuromuscular blockade is too often overlooked and considering its substantial consequences should be a reprioritized focus. what remains to be explored is the significance of low-level residual neuromuscular blockade postoperatively. keywords: neuromuscular blockade monitoring, respiratory, paralysis, complications, acceleromyography, postoperative complications, twitch monitor, peripheral nerve stimulator. abstract neuromuscular monitoring: does the use of acceleromyography compared with unaided clinical assessment result in lower occurrences of postoperative residual neuromuscular blockade in patients admitted to the post-anesthesia care unit? a literature review becky flowers, bsn, rrna affiliation: texas christian university, email: rebecca.flowers@tcu.edu funding/conflict of interest disclosure: none introduction postoperative residual neuromuscular blockade continues to affect a considerable percentage of patients admitted to the postanesthesia care unit (pacu). recent evidence suggests that 17% to 36% of patients arriving in the pacu present with objective manifestations of incomplete neuromuscular blockade reversal as determined by train-of-four (tof) ratios less than 0.9.1 patients presenting to the pacu with a tof ratio <0.9 are considered to have residual neuromuscular blockade and are at increased risk for experiencing adverse respiratory events such as reduced upper airway volume, airway obstruction, hypoxemia events, and postoperative pulmonary complications.2 research supports the use of quantitative acceleromyography to monitor neuromuscular blockade and recovery. neuromuscular monitoring includes both qualitative monitoring, such as the use of peripheral nerve stimulators and clinical sign assessment (eg, 5-s head-lift test and tongue blade stability between the incisors), and quantitative approaches (eg, acceleromyography). however, the change in practice from qualitative to quantitative monitoring is accompanied by hesitancy and uncertainty from practitioners across the nation who underestimate the occurrence of postoperative residual neuromuscular blockade and its consequences. the rationale for switching from qualitative assessments to a more quantitative approach using accelerometry needs review. the purpose of this report was to determine whether objective acceleromyography compared with subjective peripheral twitch monitors and clinical assessment is more effective in decreasing the occurrence of postoperative residual neuromuscular blockade. a literature review of what current research supports and the current trends regarding the impact of qualitative and quantitative assessment with respect to residual paralysis is provided, and a synthesis of current research follows. a table of the literature cited will be provided as an appendix for further review. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 methodology a literature search was conducted by using clinicalkey, the cochrane collaboration, embase, pubmed, and proquest. keywords such as “neuromuscular blockade monitoring,” “respiratory*,” “paralysis,” “complications,” “postoperative residual curarization,” “postoperative complications,” “twitch monitor,” and “peripheral nerve stimulator” were used. the mesh terms “neuromuscular monitoring” and “respiratory” were used for each database search. the key words were also used together by using “and” (“neuromuscular monitoring and respiratory,” “neuromuscular monitoring and respiratory paralysis,” “postoperative complications and neuromuscular monitoring,” “neuromuscular monitoring and respiratory and twitch monitor,” “neuromuscular monitoring and respiratory postoperative curarization.”) the term or (“respiratory or paralysis”) was also used. the search was restricted to the years of 2003 to 2013 and to the specialty of anesthesia. altogether, the databases yielded 336 citations with some overlap. a total of 36 articles met the inclusion criteria, of which 8 were used for the present review. reference lists of certain studies were searched manually and showed much overlap. inclusion criteria were studies of adults (18 years and older), patients undergoing surgical procedures, patients admitted to the pacu for postoperative monitoring, patients who received neuromuscular blocking agents and were given a tof ratio for reversal, and patients who were assessed by either a qualitative method or a quantitative method regarding the use of acceleromyography. the exclusion criteria were research specific to children, animals, emergency operations, or cardiac surgeries; review articles; editorials; dissertations; summaries; and foreign studies that could not be translated into english. several studies, including the remaining 28 articles found but not included here, discussed the correlation of specific agents (eg, sugammadex, rocuronium, pancuronium) to the incidence of postoperative neuromuscular blockade but did not focus on qualitative versus quantitative monitoring or expressed an opinion that shifted the focus of the study from scientific evidence to a more biased platform. these studies were excluded because they were not exclusive to the anesthesia topic. literature review a meta-analysis was conducted in 2007 to understand the impact of neuromuscular monitoring on residual neuromuscular blockade.3 despite previous studies showing an association, the use of intraoperative neuromuscular function monitoring was not shown to decrease the incidence of postoperative residual curarization.3 since this finding, recent evidence has suggested that residual neuromuscular blockade is present not only at tof ratios <0.7 but is becoming more frequent at tof ratios ≤0.9.4 another current study was conducted to determine the incidence of residual neuromuscular blockade at the time of extubation. when standard criteria (5-s head lift or hand grip, following commands, stable ventilatory pattern) were met, tracheal extubation was performed.2 among those individuals undergoing elective surgical procedures, 58% had a tof ratio <0.7 and 88% had a tof ratio <0.9 at the time of tracheal extubation.2 furthermore, upon arrival to the pacu, general weakness, 5-s eye opening and head lift, blurry vision, impaired ability to speak, and suppressed ability to cough were present among patients with a tof ratio <0.9 compared with those with a tof ratio >0.9.2,4 in another study, objective data obtained by bedside evaluation in the pacu did not predict the occurrence of residual paralysis when compared with subjective data.5 murphy et al discovered that the “presence or absence of symptoms (difficulty swallowing, dysarthria, visual disturbances) of muscle weakness was predictive of the presence or absence of a tof ratio greater than 0.90, but the presence or absence of signs (5-second headlift test, protrusion of tongue, swallowing ability, opening of eyes) of muscle weakness was not.”5(p951) therefore, bedside evaluations are not sensitive enough to confidently rule out residual postoperative neuromuscular blockade, which may account for the inaccuracy associated with the use of qualitative evaluation. if patients are still susceptible to experiencing residual paralysis at the current standard (tof ratio ≥0.9), the use of acceleromyography will identify these patients and may reduce the occurrence of residual neuromuscular blockade. perhaps the focus for prevention of residual paralysis should not be based on the conventional and convenient qualitative method of peripheral twitch count but rather on the sensitivity and reliability of qualitative versus quantitative evaluation to adequately assess tof ≥ 0.9. the occurrence of residual paralysis is nondiscriminatory at the current benchmark for reversal of a tof ratio ≥ 0.9. the evidence murphy et al5 present in which clinical tests such as the 5-s head lift test or handgrip were used to reverse patients at the time of tracheal extubation can also be maintained at a tof ratio ≤ 0.9. the presentation of postoperative residual neuromuscular blockade is associated with a broad window. residual neuromuscular blockade is present and may be symptomatic at tof ratios ≤ 0.9. tof ratios as low as <0.4 may have tof count fade that is not easily discerned.1 therefore, it is possible that anesthesia practitioners who rely solely on peripheral nerve stimulator tof count may be reversing patients from a deeper level of neuromuscular block than assumed by use of subjective assessment. similarly, using tof count and subjective assessment of fade may miss residual neuromuscular blockade postoperatively. capron et al6 conducted a study to determine if the use of acceleromyographic tof ratios could detect residual paralysis with 95% probability. the results of this study in which patients were randomly assigned to a control group or an acceleromyography monitoring group revealed that acceleromyography could not detect postoperative residual neuromuscular blockade with 95% probability at a tof ratio less than 0.9 but could reliably detect it at tof ratios equal to 0.95 and 1.0.6 residual neuromuscular blockade is a worldwide problem, yet it is incorrectly considered rare by many health care professionals. a portuguese study reported that 91 of 350 patients showed a tof ratio less than 0.9 on arrival in the pacu, giving an incidence of residual neuromuscular blockade of 26%.7 this percentage falls within the broad gap of 17-36% revealed by previous studies. not only do these data provide congruency of this unfortunate percentage, but the study also reported that “there were no statistically significant differences in the occurrence of residual blockade relating to the neuromuscular blocker used.”7(p3) the use of intermediate-acting neuromuscular blockers was thought to lower or eliminate the risk of residual paralysis. this is not true. the data suggest that the occurrence of patients being admitted to the pacu with residual neuromuscular blockade is being under-identified and that reliance on clinical signs alone is insufficient to identify all cases of residual paralysis. a survey conducted among practitioners in the united kingdom revealed that only 28% use peripheral neuromuscular monitors, whereas 42% use measurements similar to the 5-s head lift test as the diagnostic criteria for extubation.8 a poll conducted in the united states showed that only 12% use quantitative monitors to assess a patient’s readiness for recovery. of the individuals polled, only 28.8% were correct in selecting tof ratios > 0.9 as the standard for extubation criteria in the effort to avoid residual neuromuscular blockade.8 the evidence is consistent in portraying that the use of acceleromyography does decrease the occurrence of residual neuromuscular blockade and it does prevent patients from being reversed at much lower tof ratios. however, the fact remains that postoperative residual neuromuscular blockade can still occur at a tof ≥ 0.9. acceleromyography has been shown to reduce the occurrence of postoperative complications such as difficulty maintaining airway patency, yet has not been shown to eradicate its occurrence completely. at the current standard, acceleromyography is still susceptible to the occasional event of postoperative residual neuromuscular blockade, despite the lower occurrence than with qualitative assessment. consequently, the current standard is still being accepted for reversal. acceleromyography research has not only been useful in residual neuromuscular blockade research but has also contributed to the idea that the current tof ratio is not sufficient for the goal of preventing postoperative residual neuromuscular blockade. acceleromyography is useful in regards to outcomes research to assess the incidence of postoperative residual neuromuscular blockade and the theme that when not used preventable complications can arise seems to resonate in the literature. although complications occurring in the pacu are listed, problems or events beyond the pacu have not been described in great detail. the idea that postoperative residual neuromuscular blockade results in postoperative morbidity is the current speculation in the absence of sufficient scientific data. sufficient research has presented correlations among tof ratios and clinical signs and symptoms and acceleromyography versus qualitative data with respect to postoperative residual neuromuscular blockade, yet there is no evidence as to how postoperative residual neuromuscular blockade impacts patient prognosis beyond the immediate period of the postoperative pacu stay. is recovery discharge prolonged as a result of the patient’s experiencing postoperative residual neuromuscular blockade? is the experiencing of unexpected complications by the patient extraneous to the surgical procedure done as a result of experiencing residual neuromuscular blockade in the pacu? data are lacking pertaining to the complications associated with low degrees of postoperative residual neuromuscular blockade and how it impacts patient prognosis and quality of life in terms of days, months, and years. the biggest concern is that anesthesia practitioners underestimate the occurrence and possibly the severity of postoperative residual neuromuscular blockade. cost analyses and outcomes studies with respect to low-level postoperative neuromuscular blockade (tof ratios 0.85 to < 0.95 vs. tof ≥ 0.95 or = 1.0) may be the tipping point to change practice from subjective peripheral twitch monitoring or clinical assessment alone to objective acceleromyographic measurement. the answer to the question, is objective acceleromyography compared with subjective peripheral twitch monitoring and clinical assessment more effective in decreasing the occurrence of postoperative residual neuromuscular blockade? is “yes.” what remains to be explored is the significance of low-level residual neuromuscular blockade postoperatively. further investigation is warranted and ongoing. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 conclusion inconsistency in assessment of peripheral twitch monitoring data and the correlation of these data to clinical signs allows varying degrees of postoperative residual neuromuscular blockade. if the central focus is to maintain the safety and comfort of the patient, the current standard of a tof ratio ≥ 0.9 should be reevaluated, and acceleromyography must be used because peripheral twitch monitors do not provide a tof ratio but rather only a tof count. residual neuromuscular blockade is too often overlooked and considering its substantial consequences should be a reprioritized focus. residual neuromuscular blockade is a preventable patient safety problem.3 it is imperative that clinicians be equipped with the appropriate tools to adequately assess interventions. the complex nature of residual neuromuscular paralysis will make it “difficult to differentiate the adverse physiologic effects resulting from incomplete neuromuscular recovery from the residual effects of opioids, benzodiazepines, volatile anesthetics, or anesthesia induction drugs.”9 (p122) therefore, consideration of objective accelerometry use and increasing the standard of “full reversal” to a tof > 0.95 or = 1.0 needs to be considered. from the aspect of patient safety, acceleromyography is a much better tool to use than peripheral twitch monitors and certainly unaided clinical assessment. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 references 1. murphy gs, szokol jw, marymont jh, et al. intraoperative acceleromyographic monitoring reduces the result of residual neuromuscular blockade and adverse respiratory events in the postanesthesia care unit. anesthesiology. 2008;109(3):389-398. http://dx.doi.org/10.1097/aln.0b013e318182af3b. 2. murphy gs, szokol jw, marymont jh, franklin m, avram mj, vender js. residual paralysis at the time of tracheal extubation. anesth analg. 2005;100(6):1840-1845. http://dx.doi.org/10.1213/01.ane.0000151159.55655.cb. 3. naguib m, kopman af, ensor je. neuromuscular monitoring and postoperative residual curarization: a meta-analysis. br j anaesth. 2007;98(3):302-316. http://dx.doi.org/10.1093/bja/ael386. 4. murphy gs, szokol jw, avram mj, et al. postoperative residual neuromuscular blockade is associated with impaired clinical recovery. anesth analg. 2013;117(1):133-141. http://dx.doi.org/10.1213/ane.0b013e3182742e75. 5. murphy gs, szokol jw, avram mj, et al. intraoperative acceleromyography monitoring reduces symptoms of muscle weakness and improves quality of recovery in the early postoperative period. anesthesiology. 2011;115(5):946-954. appendix i: annotated bibliography table author, date study purpose/ research question study design theory/ framework model sample & setting description, size (n) data collection methods primary outcome variables results comments murphy gs, szokol jw, avram mj, et al (2013)a determine incidence and severity of symptoms of muscle weakness in patients with and without residual neuromuscular blockade. randomized clinical trial none cited 55 patients undergoing elective surgical procedures requiring neuromuscular blockade, with an anticipated duration of at least 60 minutes testing for objective evidence of muscle weakness (signs) followed by an examination for subjective evidence of residual paresis (symptoms). each patient was assessed for 16 symptoms and 11 signs of muscle weakness at each testing time at arrival to pacu, 20 min, 40 min, & 60 min after. the incidence of symptoms and the incidence of signs of muscle weakness were defined as the presence of 1 symptoms or signs, respectively, at each of the 4 testing times in the tof <0.9 and tof >0.9 cohorts. the incidence and severity of muscle weakness were significantly greater in patients with tof ratios <0.9 during the first 60 minutes of the pacu stay. signs of muscle weakness were observed less frequently than symptoms. the findings from the present investigation demonstrate that incomplete neuromuscular recovery is a primary risk factor for unpleasant symptoms of postoperative weakness. murphy gs, szokol jw, avram mj, et al (2011)b acceleromyography monitoring would diminish unpleasant symptoms of residual paresis during recovery from anesthesia by reducing the percentage of patients with tof <0.9. randomized clinical trial to either acceleromyography (quantitative) or tof (conventional qualitative monitoring) none cited, but the design was based on the findings of kopman et al from a study conducted in 1997. 155 patients undergoing elective surgical procedures requiring nmb for at least 60 min were telephoned the day before surgery for consent at a tertiary medical facility tof watch sx was placed on patients in the or and was randomized to the acceleromyography or conventional tof group. ratios and evaluation of s/s were taken at admit, 20, 40, 60 min. overall weakness scores, total number of symptoms of muscle weakness, total number of signs of muscle weakness at four time intervals during the stay in the pacu. tof ratios in the acceleromyography group at all time intervals were higher and presented with fewer symptoms of muscle weakness in comparison to the control group. the presence of objective s/s was a poor determinant of porc compared to subjective data provided by patient surveys. although tof ratios <0.9 indicate adequate response time, subjective data presented by this study propose a new dilemma that the degree of blockade observed is less than what is perceived. sauer m, stahn a, soltesz s, noeldge-schomburg g, & mencke t (2011)c the incidence of critical respiratory events, such as hypoxemia, in patients with minimal residual neuromuscular blockade and comparison of these data with those from patients with full recovery of blockade. randomized, prospective, placebo-controlled trial none cited; however, the author does cite findings from murphy et al reporting a high incidence of severe residual neuromuscular blockadecritical respiratory events in patients with early popc in the pacu. this seems to be the basis for this study. 132 adult patients, aged 18–80 years, with american society of anesthesiology i–iii physical status, undergoing orthopedic surgery under general anaesthesia, including rocuronium to produce neuromuscular blockade; 114 patients were randomized to one of two groups: neostigmine group (neostigmine) or placebo group (saline). pns and acceleromyography were used to determine tof ratios. patients were randomized to neostigmine (to be reversed at ratio > 1) or placebo group (to be reversed at ratio <1). in the pacu s/s were assessed along with the occurrence of adverse respiratory events or hypoxemia. s/s of muscle weakness and the occurrence of critical respiratory events minimal residual block was associated with a higher incidence of hypoxemia in the pacu. critical respiratory events, such as postoperative respiratory insufficiency and nonspecific respiratory problems, were not observed. among signs and symptoms of muscle weakness, swallowing difficulties occurred more often in the patients with a minimal residual block compared with patients with full recovery of neuromuscular block. this study is the first randomized, prospective, placebo-controlled investigation to examine the impact of residual neuromuscular blockade on postoperative morbidity. however, the evidence does not provide new insight regarding the impact porc can have in postoperative morbidity since its study sample was restricted to neostigmine and did not provide additional information beyond the pacu length of stay. capron f, alla f, hottier c, meistelman c, fuchs-buder t (2004)d to determine whether the acceleromyographic tof ratio detects residual paralysis with a 95% probability. randomized clinical trial none cited; however, the authors utilize evidence resulted by harper et al regarding (monitoring) differences as the basis for the aim of the study. 60 adult patients undergoing elective surgical procedures undergoing tracheal intubation random selection to group a (acceleromyography calibration) and group b (noncalibrated). negative predictive values were calculated for detecting residual paralysis at ratios 0,9, 0.95, and 1.0. ratio values correlating with the detection of residual paralysis acceleromyography is unlikely to significantly improve detection of residual paralysis, at the tof of 0.9. increasing tof recovery to 0.95 and 1.0 increased the negative predictive values in group a to 70% and 97%. overall, the use of acceleromyography can impact the detection of residual paralysis once the standard is raised to 0.95 or 1.0, but calibration prior to nmb must be performed. murphy gs, szokol jw, marymont jh, franklin m, avram mj, vender js (2005)e assess tof ratios immediately before tracheal extubation, when clinicians had determined that full recovery of neuromuscular function had occurred using standard clinical criteria. outcomes study none cited. since “no previous studies have examined the incidence and severity of residual neuromuscular block at the time of tracheal extubation,” this can be used as the foundation of this study. “123 patients scheduled for elective gynecologic or general surgical procedures, between the ages of 18 and 69 yr.” “standard clinical criteria (5-s head lift or hand grip, eye opening on command, negative inspiratory force, vital capacity breath) and peripheral nerve stimulation, acceleromyography, vas scale” presence of s/s of residual paralysis, tof ratios at time of tracheal extubation, pain per the vas scale during stay in pacu. “acceptable neuromuscular recovery (tof ratio > 0.9) was present in only a small percentage (12%) of patients immediately before removal of the endotracheal tube.” 58% had a tof ratio <0.70 and 88% had a tof ratio <0.90 at the time of tracheal extubation. ratios were significantly lower at the time of extubation in comparison to stay in the pacu. acknowledging residual paralysis can occur between tof of 0.70 and 0.90, it is appropriate to consider changing the standard to achieve tof >0.90. esteves so, martins m, barros f, et al (2013)f “determine the incidence of incomplete postoperative neuromuscular recovery (defined by a tof ratio less than 0.9) from anesthesia at pacus in portuguese hospitals.” multicenter observational study no specific framework, but “no large-scale study about the frequency of rnmb in portugal.” adult patients scheduled for elective surgery requiring general anaesthesia with neuromuscular blocking agents between july and november 2010. a total of 350 patients were used. patients who gave consent were monitored using the tof watch sx and were categorized into two groups according to tof ratios (of at least 0.90 and less than 0.90). the presence of residual paralysis in pacu and corresponding tof ratios. “ninety-one patients had a train-of-four ratio less than 0.9 on arrival in the postanaesthesia care unit, an incidence of residual neuromuscular blockade of 26%.” “there were no statistically significant differences in the occurrence of rnmb according to the neuromuscular blocker used.” grayling m & sweeney bp (2007)g to determine current anesthetic practice with respect to neuromuscular monitoring prospective survey none cited the questionnaire was distributed to a total of 715 consultants, trainees, and nonconsultant career grades anesthetists at 5 teaching hospitals and 7 district hospitals in the united kingdom. “respondents were asked to supply details regarding their use of peripheral nerve stimulators in the context of neuromuscular blockade reversal; including type of monitor and the parameters (i.e., train-of-four [tof] ratio) deemed to be acceptable for extubation. in addition, for those anaesthetists who did not use a monitor, information was sought regarding the clinical tests routinely performed at the end of surgery.” peripheral nerve stimulator usage, tof ratio standard for extubation, other “criteria used for suitability for extubation.” 28% use pns occasionally during routine practice, 62% stated they never use it, 74.7% stated standard tof ratio for extubation is >0.70, 28.8% stated standard tof ratio for extubation is >0.90. the 5-s head lift test was used by 42% and pattern of respiration was used by 36% when pns was not used for extubation. finally, 17% state neuromuscular monitoring similar to the pns should be used in practice. the survey provides a quick glance of the consensus regarding neuromuscular monitoring practice; however, it would be interesting to see how many of the respondents believe porc is directly impacted by the use or ill-use of pns. overall, it does provide the reader with an idea of how extubation criteria are determined. naguib m, kopman af, ensor je (2007)h examine the effect of intraoperative monitoring of neuromuscular function on the incidence of porc meta-analysis random effects model data were analyzed from 24 studies (13 randomized and 11 observational studies). electronic literary search of various databases (pubmed, cochrane controlled trials register, web of knowledge) from 1975-2006. incidence of porc “neuromuscular function was monitored in 823 patients (24.4%). a simple peripheral nerve stimulator was used in 543 patients, and an objective monitor was used in 280.” “we could not demonstrate the use of an intraoperative neuromuscular function monitor decreased the incidence of porc.” abbreviations: nmb, neuromuscular blockade; or, operating room; pacu, post-anesthesia care unit; pns, peripheral nerve stimulation; popc, postoperative pulmonary complication; porc, postoperative residual curarization; rnmb, residual neuromuscular blockade; s/s, signs and symptoms; tof, train-of-four. amurphy gs, szokol jw, avram mj, et al. postoperative residual neuromuscular blockade is associated with impaired clinical recovery. anesth analg. 2013;117(1):133-141. http://dx.doi.org/10.1213/ ane.0b013e3182742e75. bmurphy gs, szokol jw, avram mj, et al. intraoperative acceleromyography monitoring reduces symptoms of muscle weakness and improves quality of recovery in the early postoperative period. anesthesiology. 2011;115(5):946-954. http://dx.doi.org/10.1097/aln.0b013e3182342840. csauer m, stahn a, soltesz s, noeldge-schomburg g, mencke t. the influence of residual neuromuscular block on the incidence of critical respiratory events. a randomised, prospective, placebo-controlled trial. eur j anaesthesiol. 2011;28(12):842-8. doi: 10.1097/eja.0b013e328345cd11. dcapron f, alla f, hottier c, meistelman c, fuchs-buder t. can acceleromyography detect low levels of residual paralysis? a probability approach to detect a mechanomyographic train-of-four ratio of 0.9. anesthesiology. 2004;100(5):1119-1124. emurphy gs, szokol jw, marymont jh, franklin m, avram mj, vender js. residual paralysis at the time of tracheal extubation. anesth analg. 2005;100(6):1840-1845. http://dx.doi.org/10.1213/01. ane.0000151159.55655.cb. festeves s, martins m, barros f, et al. incidence of postoperative residual neuromuscular blockade in the postanaesthesia care unit: an observational multicentre study in portugal. eur j anaesthesiol. 2013; 30(5): 243-9. doi: http://dx.doi.org/10.1097/eja.0b013e32835dccd7. ggrayling m, sweeney bp. recovery from neuromuscular blockade: a survey of practice. anaesthesia. 2007;62(8):806-809. hnaguib m, kopman af, ensor je. neuromuscular monitoring and postoperative residual curarization: a meta-analysis. br j anaesth. 2007;98(3):302-316. http://dx.doi.org/10.1093/bja/ael386. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 anesthesia ejournal volume 2 issue 2 2014 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 abstract perioperative management to prevent allogeneic blood transfusion in liver surgery robbin rabbani, crna, ms michele e. gold, crna, phd affiliations: this article was written by robbin as student at usc. correspondence: robbinra@usc.edu michele e. gold, crna, phd is program director, program of nurse anesthesia in the keck school of medicine of the university of southern california, los angeles. correspondence: mgold@usc.edu considerable surgical blood loss is a recognized complication of hepatic surgery. allogeneic blood product transfusion can be used to treat anemia related to surgery. however, research has shown that transfusing blood products exposes the patient to multiple risk factors. methods of surgical and anesthetic management of blood loss such as establishing acute normovolemic hemodilution and maintaining low central venous pressure can prevent the need for a transfusion. this case study outlines the use of acute normovolemic hemodilution and low central venous pressure to prevent allogeneic blood transfusion in a patient undergoing hepatic resection. keywords: allogeneic transfusion; central venous pressure, hemodilution, hepatic resection, hepatectomy. acknowledgments the authors thank ben lindsey, crna, ms, for his guidance and encouragement in this case and for his continued efforts to educate future certified registered nurse anesthetists at the university of southern california. introduction advances in the operative and anesthetic techniques of hepatic resection have decreased associated morbidity and mortality. administration of allogeneic blood products to correct anemia and coagulopathy is routine in this surgical population, although adverse events occur with significant frequency. immunosuppression, infection, transfusion reactions, and early recurrence of cancer have all been associated with allogeneic blood transfusions.1-3 the incidence of these complications may be as high as 1 in 2000 units of red blood cells (rbc) transfused. furthermore, the incidence of transfusion errors has been estimated at 1 in 14,000 units of blood transfused.4 anesthesia practitioners must focus on careful perioperative management to reduce rbc loss and prevent allogeneic blood transfusions. techniques traditionally used to prevent allogeneic transfusion during hepatic resection include clamping the major hepatic vessels, decreasing retrograde hepatic blood flow, and diluting the circulating rbc concentration.1,2 in this case report, acute normovolemic hemodilution (anh) and maintenance of a low central venous pressure (cvp) were implemented to reduce the concentration of rbc lost, decrease overall blood loss, and prevent allogeneic blood transfusion. mailto:robbinra@usc.edu mailto:mgold@usc.edu anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 2 2014 case summary a 53-year-old woman with an american society of anesthesiologists (asa) physical status 3 presented for open surgical resection of a liver mass. she was 163 cm tall and weighed 83 kg. her medical history included type 2 diabetes mellitus, hypertension, and rectal cancer. preoperative medications were metformin and valsartan. the patient’s surgical history included transrectal excision of rectal cancer in 2009. preoperative laboratory values were as follows: hemoglobin 13.4g/dl, hematocrit (hct) 40.2%, blood urea nitrogen 13 mg/ dl, creatinine 0.66 mg/dl, glucose 162 mg/dl, protime (pt) 10.4 seconds, international normalized ratio 1.0, and partial thromboplastin time (ptt) 28 seconds. the chest x-ray showed no acute disease; the electrocardiogram (ecg) showed a possible inferior infarct. a myocardial perfusion scan was performed after the ecg. the scan showed normal perfusion, ventricle size, and ejection fraction and no wall motion abnormalities. the ecg results did not clinically correlate with the perfusion scan, and the patient was cleared for surgery. the preoperative vital signs were: heart rate 106 beats per minute, blood pressure 116/80 mm hg, respiratory rate 19 breaths per minute, and temperature 36.6°c. the patient was given 2 mg midazolam intravenously (iv) before entering the operating room. standard asa monitors were connected to the patient, and a face mask delivering 6 l/ min oxygen was applied. the patient was placed in a seated position, and the regional anesthesia team inserted a thoracic epidural at the level of t8 without complications. the patient was positioned supine, pre-oxygenated for 5 minutes, and induced with 100 mg lidocaine, 100 mcg fentanyl, 150 mg propofol, and 10 mg cisatracurium. a 7.0-mm endotracheal tube (ett) was inserted into the trachea. general anesthesia was maintained with desflurane 5%-6% inspired concentration in a mixture of 0.5 l/ min oxygen and 0.5 l/min air. a 20-gauge right radial arterial catheter and a 7f triplelumen central venous catheter (cvc) were placed under sterile conditions. the cvp was transduced through the cvc. the patient was placed in a 15-degree trendelenburg position. two citrate phosphate dextrose (cpd) bags were attached to the cvc for phlebotomy. about 700 ml blood were collected between both bags, which were stored in a cooler and agitated periodically to prevent clotting. albumin 5% (500 ml) and plasmalyte (600 ml) were administered iv over 30 minutes. post-phlebotomy and hemodilution lab specimens were processed in the main hospital laboratory and resulted in hgb 11.5 g/dl and hct 35%. before the intraparenchymal dissection, the surgeon clamped the hepatic arteries and portal vein. during resection, cvp was maintained at ≤4 mm hg with administration of a nitroglycerin (ntg) infusion. as blood loss increased, iv fluids and phenylephrine were needed to maintain the blood pressure within 10%-20% of preoperative values. total administration of ntg was 2100 mcg, and administration of phenylephrine was 2450 mcg. total iv fluid administration was 3 l crystalloid and 500 ml albumin. total blood loss for the operation was estimated at 500 ml, and urine output was 250 ml. before extubation, 700 ml whole blood in the cpd bags were transfused to the patient over 30 minutes, and the phenylephrine infusion was adjusted downward and turned off. epidural morphine (3 mg) was administered before tracheal extubation. return of neuromuscular function was determined by trainof-four monitoring with 4/4 twitches and sustained tetany. the patient met extubation criteria to maintain spontaneous ventilation, and the ett was removed. the patient was transferred to the postanesthesia care unit (pacu) with 6 l/ min oxygen administered via face mask. after 30 minutes in the pacu, the blood pressure began to decline but responded to administration of 500 ml normal saline. the patient did not complain of pain. to prevent further decline in blood pressure, epidural infusion of local anesthetic was not initiated. after 30 minutes in the pacu, the patient reported pain at the surgical site. she was given iv hydromorphone for pain management in the pacu and throughout her hospitalization. postoperative hematology results in the pacu were hbg 8.7 g/dl and hct 25.5%. on postoperative day 2, the patient’s hgb increased to 9.0 g/dl and hct to 26.1%. the epidural was used only for morphine administration at the end of surgery and was discontinued on postoperative day 3 with no sequelae. no allogeneic blood products were transfused during hospitalization. discussion hepatic resection is the preferred management for malignant and benign masses of the liver.3 over the past few decades, advances in intraoperative management have reduced morbidity and mortality associated with this surgical population.3 however, acute blood loss remains a significant challenge for both surgeons and anesthetists. often, these losses result in the transfusion of allogeneic blood products.2 serious complications such as renal injury, immunosuppression, sepsis, hemolytic reactions, acute lung injury, and infection can occur after these transfusions.4,5 to prevent these complications, anesthetic management should focus on interventions to minimize surgical blood loss. in this case, the following plan was implemented to accomplish this goal: before incision, anh would be used and, during liver parenchymal resection, cvp would be maintained at ≤4 mm hg. establishment of anh involves the removal of blood cells, resulting in rbc dilution and lower hgb and hct, followed by return of the patient’s original blood concentrated with rbcs and coagulation factors. by replacing the blood that was removed with colloid or crystalloid, the blood lost is diluted. this results in a decrease in the number of lost rbcs during intraoperative bleeding and maintains intravascular volume and cardiac output.3,6 transfusing blood at the end of surgery can increase rbc count, restore blood volume, and improve coagulability.4 for this patient, 2 cpd bags were used to remove about 700-800 ml. however, larger volumes of blood can be safely removed during anh.3,6,7 hemodilution to hgb levels of 8.0 g/dl can easily be achieved if the patient’s hemodynamic status is maintained during the procedure. the amount of blood that needs to be removed to achieve a target hgb or hct can be estimated by applying the equation in figure 1.3,6 substituting the patient’s preand post-phlebotomy hct confirms that the estimated amount of blood removed in the 2 cpd bags was accurate. the effectiveness of anh in reducing allogeneic blood transfusion has been debated. table 1 includes a number of studies for review. a 2004 meta-analysis reviewed 42 randomized controlled trials using anh and concluded that there was no anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 2 2014 significant reduction in the incidence or relative risk of allogeneic blood transfusion. the volume of blood transfused in the anh group was significantly less than in the usual-care groups. although the volume of blood transfused was decreased by 1-2 units, it did not affect the incidence of allogeneic transfusion.8 however, this meta-analysis had limitations; most of the studies were not conducted in the united states, and only 12 had the outcome evaluator blinded to the study group. in addition, only one study was specific to hepatic surgery. a 2002 study specific to anh in hepatic surgery showed a significant increase in the incidence of allogeneic transfusion when anh was not used.9 four patients in the anh group received an allogeneic blood transfusion, compared with 14 patients in the control group. half the patients in the control group received only 1 unit of blood. this could have been avoided by using anh.9 in 2006, the asa conducted a research review and published its guidelines for perioperative blood transfusion. the asa concluded that there is statistically significant evidence to support using anh to reduce perioperative allogeneic blood transfusion.10 more recent research also supports these findings. jarnagin et al, who studied patients undergoing hepatic resection, demonstrated a 50% reduction in rbc transfusion using anh.3 guo’s 2013 study compared 30 elderly patients undergoing hepatic resection randomly assigned to either anh or a control group.7 this study also identified a significant decrease in blood transfusion in the anh group by more than 100 ml rbc. although fibrinogen was decreased and pt/ptt were prolonged after anh, these values were within normal limits and improved to values similar to the control group after transfusion of homologous blood.7 anh facilitated a reduction in the concentration of rbcs lost, and allogeneic blood transfusion was not necessary, possibly due to anh therapy. maintenance of a low cvp (≤5 mm hg) has been identified as a potential means to reduce blood loss during hepatic resection.2,11 a low cvp results in a decrease in retrograde pressure and flow through the dissected liver parenchyma. the surgical steps involved in hepatic resection include an initial clamping of the hepatic arteries and portal vein, causing total hepatic inflow occlusion before parenchymal dissection. the increase in pressure from the retrograde blood flow into the hepatic veins increases bleeding through the hepatic sinusoids. lowering the cvp can reduce these pressures and blood flow to the liver to decrease overall blood loss (table 2). a research trial to evaluate this phenomenon studied two groups of 50 patients undergoing hepatic resection (cvp ≤5 mm hg or cvp >5 mm hg). demographic data and transfusion thresholds were equivalent in both groups. the low cvp group recorded a roughly 80% reduction in blood loss and significantly fewer blood transfusions.11 multiple methods can be used to reduce cvp while maintaining normotension. a 2006 study of 50 patients undergoing hepatic resection used iv ntg infusion and the trendelenburg position, limited iv fluid administration, and used iv furosemide to maintain cvp at 2-4 mm hg. compared with the control group, the low cvp group had a 69% reduction in blood loss and a 32% reduction in allogeneic transfusion.12 in 2008, a trial of 46 patients used similar methods to reduce cvp to 2-4 mm hg. this trial evaluated the volume of intraoperative blood loss and blood product administration and monitored renal function to postoperative day 7. the low cvp group demonstrated a 49% reduction in intraoperative blood loss and a 44% decrease in volume of blood product administration compared with the control group. there were no differences in postoperative renal function in either group.13 in this case, cvp was maintained at ≤4 mm hg using both the trendelenburg position and iv ntg infusion. these interventions may have been responsible for the lower intraoperative blood losses. when altering a patient’s hemodynamic status with anh and lower cvp, the impact on comorbidities must be addressed. in this case, the patient’s hypertension was well controlled, without signs of compromised perfusion, as evidenced by a preoperative normal myocardial perfusion scan and normal chemistry values. an ntg infusion adjusted to a rate of 25 mcg/ min was effective at reducing the cvp to ≤4 mm hg. as surgical blood losses increased, the ntg infusion was discontinued and a phenylephrine infusion adjusted to 60 mcg/min, which maintained blood pressure at 89/48 to 115/60 mm hg. constant communication between the surgeon and anesthetist enabled vigilant monitoring of current and anticipated blood losses, which informed decisions on vasoactive therapies and return of the patient’s blood. when the vasopressor infusion was used to support blood pressure and the hepatic resection was completed, a decision was made to re-transfuse the patient. as blood pressure returned to baseline levels, the phenylephrine drip was discontinued. to reduce postoperative pain, the epidural was activated during incision closure with 3 mg morphine. the anesthetic management goals to maintain the patient’s cvp at ≤4 mm hg and blood pressure within 20% of the baseline were met throughout the surgery. anh and maintenance of low cvp reduced surgical blood loss and precluded the administration of allogeneic blood transfusion during hepatic resection. current evidence supports the use of these methods in hepatic surgery.1-3,6,10,11,14 the intraoperative management of hepatic resection should include anh and low cvp to reduce the concentration of surgical rbc losses and overall intraoperative blood loss. these interventions can prevent exposing the patient to allogeneic blood products and the associated risks and complications. estimate amount of blood to be removed vl = ebv x ((hi – hf)/hav) apply equation to preand post-phlebotomy lab values vl = (65 x 83) ([40.2 – 35.0] / 37.6) = 746 ml of blood removed figure 1. ebv, estimated blood volume; hi, initial hematocrit; hf, target hematocrit after hemodilution; hav, average between hi and hf; vl, total volume to be removed. anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 2 2014 table 1. methodology and outcomes of studies on use of acute normovolemic hemodilution during hepatic resection. author and date methodology outcomes segal et al 20048 meta-analysis of 42 trials: 18 cardiac surgeries, 13 orthopedic procedures, 4 radical prostatectomies, 3 spine surgeries, 2 aortic surgeries, 1 thoracic surgery, and 1 liver resection no significant decrease in relative risk of receiving allogeneic blood transfusion (p = 0.3). total volume of allogeneic blood transfused intraoperatively and postoperatively was significantly less in anh group (p <0.001) matot et al 20029 prospective rct of 78 patients undergoing hepatic surgery for tumor excision. control group (n=39) did not undergo anh therapy; anh therapy group (n=39) underwent phlebotomy (hct = 24%). fluid administration was controlled in both groups to prevent increases in cvp values. indication for blood transfusion was standardized in both groups to hct = 20% intraoperative blood loss, cvp, and urine output were similar in both groups. 14 patients in control group received allogeneic blood transfusion, compared with 4 patients in anh group (p = 0.014). 50% of patients in control group were transfused only 1 unit of blood. there were no differences in hct, creatinine, pt, and ph between control group and anh group jarnagin et al 20083 prospective rct of 130 patients undergoing hepatic surgery comparing anh with standard anesthetic management (65 patients/group). target diluted hgb = 8.0 mg/dl. low cvp was standardized in both groups. transfusion trigger was hgb < 7.0 g/ dl in both groups. 50% reduction in transfusion of allogeneic red cells and fresh frozen plasma in anh group (p <0.05). 66.6% of standard management patients with ≥1500 ml blood loss were transfused intraoperatively compared with none in anh group (p <0.01). results showed 85% reduction in allogeneic transfusion requirement guo et al 20137 prospective rct of 30 patients aged 60-70 undergoing hepatic surgery for tumor excision. patients were randomly assigned to anh group or control group (15 patients/group). blood samples were drawn 5 times: before induction (t1), 30 min after anh (t2), 1 hour after surgery start (t3), immediately after surgery (t4), and 24 hours after surgery (t5). anh group target hct = 28%. transfusion threshold hgb = 8 g/dl or hct = 25% intraoperative blood losses were similar in both groups. volume of blood transfusion was significantly less in anh group (350.5 ± 70.7 ml vs 457.8 ± 181.3 ml; p <0.05). compared with data before anh, pt and ptt were significantly prolonged in anh group for times t2 and t3 (values were still within normal limits). concentration of fibrinogen was significantly reduced after anh (within lower limit). fibrinogen values increased after transfusion of homologous blood removed by anh anh, acute normovolemic hemodilution; cvp, central venous pressure; hct, hematocrit; hgb, hemoglobin; ppt, partial thromboplastin time; pt, protime; rct, randomized controlled trial. table 2. methodology and outcomes of studies on maintenance of low central venous pressure during hepatic resection. author and date methodology outcomes jones et al – 199811 prospective trial with 100 patients undergoing hepatic resection. patients were categorized into 2 groups: cvp ≤5 and cvp >5. transfusion threshold was hgb =10 g/dl for both groups median blood loss for cvp ≤5 = 200 ml; median blood loss for cvp >5 = 1000 ml (p = 0.0001). group with cvp ≤5, 2 patients received blood transfusion compared with group with cvp >5 had 25 patients that received blood transfusion (p = 0.0008) wang et al – 200612 prospective rct with 50 patients undergoing hepatic resection classified equally into low cvp group (cvp = 2-4 mm hg and sbp >90 mm hg) and control group (no cvp lowering). cvp was maintained in low cvp group by using trendelenburg position, limiting fluid volume, iv ntg infusion, and iv furosemide if necessary. transfusion thresholds were equivalent for both groups, at 8.0 g/dl total blood loss was significantly lower in low cvp group compared with control group (p <0.01) (904 ml vs 2329 ml). 56% of patients in control group received blood transfusion compared with 24% in low cvp group (p <0.05). low cvp group had significantly shorter hospital stays (p <0.05). postoperative complications were equivalent in both groups. there were no differences in postoperative hepatic and renal functions liu et al 200813 prospective rct of 46 patients undergoing liver resection classified equally into low cvp group (cvp = 2-4 mm hg, sbp >90 mm hg, and mean blood pressure >60 mm hg) and control group (no cvp lowering). cvp was controlled in low cvp group by using trendelenburg position, limiting fluid volume administration, and iv ntg infusion and iv furosemide. transfusion threshold was same for both groups, at hgb <8.0 g/dl total intraoperative blood loss was significantly less in low cvp group (p <0.01) (375 ml vs 733 ml). rbc transfusion was significantly less in low cvp group, with average 206 ml vs 365 ml in control group (p <0.05). 7 patients in low cvp group required blood transfusion vs 13 patients in control group. there were no changes in bun or creatinine on postoperative days 1, 3, or 7 bun, blood urea nitrogen; cvp, central venous pressure; iv, intravenous; ntg, nitroglycerin; rbc, red blood cell; sbp, systolic blood pressure. anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 2 2014 references 1. huntington jt, royall na, schmidt cr. minimizing blood loss during hepatectomy: a literature review. j surg oncol. 2014;109(2):81-88. 2. page aj, kooby da. perioperative management of hepatic resection. j gastrointest oncol. 2012;3(1):19-27. 3. jarnagin wr, gonen m, maithel sk, et al. a prospective randomized trial of acute normovolemic hemodilution compared to standard intraoperative management in patients undergoing major hepatic resection. ann surg. 2008;248(3):360-369. 4. joyce ja. toward reducing perioperative transfusions. aana j. 2008;76(2):131-137. 5. shander a. transfusion medicine. audio-digest anesthesiology. october 28, 2013; 55(40). http://www.audio-digest.org/pages/ htmlos/subscription.html?sub1=anesthesiology. accessed october 17, 2014. 6. lindstrom e, johnstone r. acute normovolemic hemodilution in a jehovah’s witness patient: a case report. aana j. 2010;78(4):326-330. 7. guo j, jin x, yu j, et al. acute normovolemic hemodilution effects on perioperative coagulation in elderly patients undergoing hepatic carcinectomy. asian pac j cancer prev. 2013;14(8):4529-4532. 8. segal jb, blasco-colmenares e, norris ej, guallar e. preoperative acute normovolemic hemodilution: a meta-analysis. transfusion. 2004;44(5):632-644. 9. matot i, scheinin o, jurim o, eid a. effectiveness of acute normovolemic hemodilution to minimize allogeneic blood transfusion in major liver resections. anesthesiology. 2002;97(4):794-800. 10. practice guidelines for perioperative blood transfusion and adjuvant therapies: an updated report by the american society of anesthesiologists task force on perioperative blood transfusion and adjuvant therapies. anesthesiology. 2006;105(1):198-208. 11. jones rm, moulton ce, hardy kj. central venous pressure and its effect on blood loss during liver resection. br j surg. 1998;85(8):1058-1060. 12. wang wd, liang lj, huang xq, yin xy. low central venous pressure reduces blood loss in hepatectomy. world j gastroenterol. 2006;12(6):935-939. 13. liu y, cai m, duan s, et al. effect of controlled low central venous pressure on renal function in major liver resection. chinese-german j clin oncol. 2008;7(1):7-9. 14. li z, sun ym, wu fx, yang lq, lu zj, yu wf. controlled low central venous pressure reduces blood loss and transfusion requirements in hepatectomy. world j gastroenterol. 2014; 20(1): 303-309. anesthesia ejournal volume 4 issue 1 2016 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 page 16 postoperative residual curarization: a case report clay freeman, crna, dnp introduction a 67-year-old male was admitted with chronic hepatitis c and signs of cirrhosis. he presented with pitting edema scored as a plus one and mild jaundice. during an ultrasound screening and hepatic evaluation, a 1-cm mass on the liver was discovered. initial clinical assessment and diagnostic imaging indicated suspicion for hepatocellular carcinoma with possible arterial and venous involvement. a laparoscopic ultrasound-guided biopsy and radiofrequency ablation of his liver lesion was planned after overnight observation. the procedure was planned to be converted to an open laparotomy if necessary intraoperatively. in addition to chronic hepatitis c, the patient’s history was significant for hypertension, hyperlipidemia, and coronary artery disease. his overall body habitus was considered frail with a height of 175 cm, weight of 71 kg, and body mass index of 23. home medications included lisinopril, aspirin, amlodipine, atenolol, and simvastatin. he denied any history of a stroke, but mild ataxia was present along with an unsteady gait related to hip dysfunction. he had used a walker for ambulation for the past several years and lived at home by himself. he displayed general weakness but stated that he was able to complete his activities of daily living without assistance. he had a prior history of heavy alcohol abuse for “many years” but denied current alcohol intake, with his last use approximately 5 years ago. he maintained a 20-pack-year smoking history. he denied any shortness of breath or difficulty breathing, although he stated that he did have a chronic cough. the patient’s lung sounds were clear to auscultation. his oxygen saturation was 94% on room air in the preoperative holding area. past surgical history included an uneventful triple-vessel coronary artery bypass graft surgery in 2001 with no chest pain since that time and a laparoscopic cholecystectomy, which was also uneventful and free of anesthetic complication. previous anesthesia records from these procedures were not available. the patient’s current liver function tests indicated hepatic damage as demonstrated by the following values: alanine aminotransferase (alt), 100 u/l; aspartate aminotransferase (ast), 91 u/l; and partial thromboplastin time (ptt), 14.9 s. laboratory values prior to surgery included the following: hemoglobin, 13.7 g/dl; hematocrit, 40.2%; platelets, 288,000; and international normalized ratio, 1.2. the patient had no known drug allergies. abstract an elderly frail male patient with a history of liver disease presented for a laparoscopic ablation of a liver mass. nondepolarizing neuromuscular blockade agents were used to maintain a train-of-four count of 1 to 2 twitches throughout the surgery. at the conclusion of the operation the patient’s neuromuscular blockade was assessed via trainof-four at the corrugator supercilii, and the patient was given neuromuscular blockade reversal agents. approximately 10 minutes after his arrival to the recovery unit, the patient presented with symptoms suggestive of postoperative residual curarization. this case report demonstrates the importance of objective assessment strategies when evaluating neuromuscular blockade. monitoring twitches at the adductor pollicis at the end of surgery gives the practitioner better evidence of a more complete neuromuscular blockade recovery. the dosing and timing of neuromuscular blockade reversal agents should be especially prudent to ensure adequate patient recovery and safety postoperatively. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 17 case summary the patient was brought into the operating room and assisted onto the operating table, standard monitors were applied, and preoxygenation with 100% oxygen was initiated. a standard induction sequence with intravenous (iv) fentanyl 100 mcg, lidocaine 100 mg, propofol 130 mg, and rocuronium 50 mg was performed through the patient’s existing 20-gauge peripheral iv line. mask ventilation was easily accomplished with an oral airway in place. intubation with a size 8.0 endotracheal tube was achieved with direct laryngoscopy grade 1 view. sevoflurane was titrated to an end tidal concentration of 2.0%. a 16-gauge iv line was placed following induction and connected to a hot line with a fluid warmer. a peripheral nerve stimulator (pns) was utilized to assess neuromuscular blockade (nmb) throughout the procedure. vecuronium at a dose of 0.5 to 1 mg was administered approximately every 20 to 30 minutes upon recognition of a train-of-four (tof) count at 2 or 3 with the goal to maintain 1 to 2 twitches on tof. the surgical procedure was initiated and proceeded without incident. the patient’s vital signs remained stable throughout the procedure and ventilation was adequately achieved with a volume control mode, tidal volume of 500, rate of 12, 50% fraction of inspired oxygen (fio2), and positive end expiratory pressure of 5 cmh2o. a total of 11 mg of vecuronium, 7 mg of morphine, and 200 mcg fentanyl were given during the 3-hour case, with the last dose of 1 mg vecuronium given 1.5 hours before surgical closure. upon closure of the 5 laparoscopic incisions, twitches were assessed at 2 twitches out of 4 at the corrugator supercilii muscle. a reversal of nmb, 2 mg neostigmine along with 0.4 mg glycopyrrolate, was administered. the patient began to initiate respirations and was taken off the ventilator. he was able to maintain adequate tidal volumes at this time. morphine 2 mg was then slowly titrated intravenously to achieve a respiratory rate of 10 to 12 breaths per minute. sevoflurane was discontinued and shortly thereafter the patient was extubated awake after observing the patient was able to sustain a head lift of greater than 5 s upon command. the patient was then transported to the postanesthesia care unit (pacu) without oxygen. his vital signs upon arrival were as follows: blood pressure, 166/79 mmhg; heart rate, 95 in sinus rhythm; 100% oxygen saturation; respiratory rate, 17; and temperature, 36.60c per external monitor. the patient was awake and following commands without signs of distress. he denied any pain or other complaints at the time of arrival to the pacu. approximately 10 minutes later, the nurse anesthetist, the resident nurse anesthetist, and an anesthesiologist were paged to the pacu to evaluate the patient. he appeared to be having difficulty breathing and swallowing, with overall anxiety. his blood pressure was 210/110 mmhg with tachycardia of 120 beats per minute. he was unable to verbalize but nodded appropriately when asked if he was short of breath. his breath sounds were diminished bilaterally on auscultation. his oxygen saturation remained greater than 92%. respirations were then assisted at a rate of approximately 20 breaths per minute with a selfinflating resuscitator and 100% fio2. labetalol 10 mg was given intravenously to decrease his blood pressure. an additional dose of nmb reversal, 2 mg neostigmine and 0.4 mg glycopyrrolate, was administered. after approximately 5 minutes of assisted ventilation, the patient demonstrated significant improvement in respirations. his vital signs returned to baseline and he was able to breathe effectively on his own. a 12-lead electrocardiogram and chest x-ray were ordered and the findings were unremarkable for acute events. the patient was later discharged to the intensive care unit, as planned preoperatively. upon assessment the next day, the patient denied any concerns or complaints of anesthetic complications. the patient was discharged several days later without further incidents. he was seen in the clinic 1 week later with no reports of significant events throughout his hospitalization. review of the current evidence residual paralysis from nmb is a serious and underrecognized problem postoperatively. historically, residual paralysis has been identified as postoperative residual curarization (porc) since it was first noticed after the use of curare. the occurrence of porc remains under-estimated among practitioners.1 indeed, the decision to use reversal agents after nmb varies among international communities and even individual practitioners.1 much of the debate is likely due to the high degree of variability in monitoring for the degree of nmb. a number of ways exist to measure nmb but none are more prevalent than the pns.1,2 however, the use of the pns intraoperatively has not demonstrated a decreased incidence of porc when compared with more subjective measures such as a patient-sustained head lift.2-4 important in the use of the pns is how it is utilized and how the results are interpreted by the provider. the different sites used for tof monitoring produce variable results.5-9 the corrugator supercilii muscle and adductor pollicis muscle are 2 frequently monitored sites. the corrugator supercilii muscle demonstrates a recovery time comparable with that of the diaphragm.5,7,8 the adductor pollicis has a more delayed recovery time than that of the corrugator supercilii muscle.2,5,6 the adductor pollicis is in fact one of the muscles that is part of the last group of muscles to recover from nmb.5,7 interpretation of tof is also a crucial aspect in evaluating the degree of neuromuscular recovery. a tof ratio of at least 0.7 was previously believed to be an acceptable criterion for determining patient readiness for extubation.1,2,4,6 however, several studies have evaluated whether this criterion is satisfactory enough to avoid adverse events in the postoperative recovery period. further evaluation has demonstrated a tof value of 0.9 or greater to be preferable to lessen the likelihood of respiratory compromise in patients who received nmb.3-6 this is best appreciated in the demonstration that even healthy volunteers complain of some difficulty breathing with a tof ratio of 0.7 and even up to 0.9.35,7,8 although the diaphragm is functional at a tof of 0.7, some of the upper airway and esophageal muscles remain weak.3-5,10 such aspects predispose the patient to increased risk of aspiration, airway obstruction, atelectasis, pneumonia, and hypoxia.3,7 complicating matters when determining adequate reversal is the realization that many of the subjective measures still demonstrate some degree of nmb.2 subjective criteria such as a sustained head lift, purposeful hand grip, and adequate patient tidal volumes can still be present with a tof ratio of 0.5.4-6,8 the use of nmb antagonism also remains debated owing to mixed understandings of neuromuscular blocking agents and nmb antagonists. the occurrence of porc has been assumed to have decreased in part due to the addition of intermediateacting paralytics such as rocuronium and cisatricurium.11,12 upon experimentation, however, studies have not revealed this to be true.4,5 differences in incidences of porc are seen only when long-acting paralytics such as pancuronium are compared with paralytics like vecuronium, which is intermediate-acting.11,12 evidence suggests that practitioners are also underestimating the time necessary for full recovery after a single dose of an intermediate-acting agent.1,5,12 residual muscle weakness of clinical significance may continue for more than 2 hours.1,3,5 understanding recovery time is especially prudent when considering the sometimes unpredictable nature of steroid-based neuromuscular blocking agents.1,5 reversal agents exert their effects by increasing acetylcholine at the neuromuscular junction and inhibiting cholinesterase, thereby indirectly competing with neuromuscular blocking agents. reversal agents are most effective when given at 2 twitches or greater.3,4,12 giving neostigmine before the patient has 2 twitches can result in delayed recovery and incidence of porc.3,4,12 discussion how to best reverse the neuromuscular blocked patient is clearly a subjective decision at this time.1,7,8 the nmb in the present case report was monitored, maintained, and reversed according to typical practices by anesthesia providers. the criteria used to determine readiness for extubation are also considered typical within the anesthesia community.1,7,8 our patient demonstrated what appeared to be an adequate count of twitches on tof prior to administration of the reversal agent. afterward, a tof count of 4 twitches was achieved and the patient was extubated awake after a sustained head lift was confirmed. spontaneous ventilation tidal volumes were around 5 ml/kg. however, the patient presented evidence of porc in the pacu. assessment of patient vital signs, respiratory rate, and pupillary size decreased suspicion of respiratory compromise due to opioids or benzodiazepines. although visual assessments are not conclusive, differential diagnoses were quickly reduced to likely porc. the identification of porc was reinforced by patient improvement 5 minutes after administration of a repeat dose of neostigmine. the patient’s improvement in motor function correlated with the onset time of the reversal effects of neostigmine. the patient again showed clinical signs of adequate recovery (sustained head lift to command, adequate tidal volumes, ability to cough) and was extubated. considering what appeared to be a typical anesthetic case utilizing nmb, reflection on this case discloses the limitations in current practices. more specific and detailed assessment may have prevented this scenario of porc. the site of monitoring for twitches can demonstrate a noticeable difference in measured outcomes. this patient’s twitches were examined at the corrugator supercilii muscle. a more appropriate evaluation should be made by moving the pns to the ulnar nerve and monitoring the adductor pollicis muscle at the conclusion of surgery, because the adductor pollicis is one of the last muscle groups to recover from nmb. monitoring at sites that recover more quickly puts the patient at greater risk for porc. the patient may still be compromised in respiratory function even when he or she can sustain a head lift of greater than 5 s.4,7,8 it is also preferable if a patient’s motor function has spontaneously returned with greater than 2 twitches on tof count before a nmb antagonist is administered. additionally, dosing nmb antagonism on the basis of the degree of neuromuscular recovery is of critical importance to avoid porc. upon recovery of 2 tof twitches, an ideal dose of neostigmine is 0.05 mg/kg.4,5 with these doses in mind, the patient in this case was optimally antagonized only after his second administration of neostigmine in the pacu. all these measures are especially pertinent in high-risk patients. the patients who are likely to recover neuromuscular function more slowly than anticipated are the elderly, the obese, and those with kidney or liver malfunction.1,12 with respect to the patient’s age, history, and the procedure being performed, a high degree of awareness for possible porc should be suspected. much can also be gained in the understanding of residual nmb across the entire anesthesia practice from studying scenarios such as these and what the literature suggests. the american association of nurse anesthetists standard v states, “when neuromuscular blocking agents are administered, monitor neuromuscular response to assess depth of blockade and degree of recovery.”7 while the literature does not suggest an increased incidence of porc whether neuromuscular monitoring is used or not,4,5 standards set forth by professional organizations are encouraged. clearly more teaching and discussion are needed across the entire anesthesia practice to decrease the disparity among practitioners. such disparities include appropriate neuromuscular monitoring, the interpretation of monitoring results, length of time until spontaneous nmb recovery, and timing of reversal agents. understanding these facets is vital to improving patient care and increasing the quality of anesthesia care. porc is a true risk for post-anesthetic patients that can result in delayed recovery, increased morbidity, and increased risks of aspiration and other adverse respiratory events. these risks should demonstrate to anesthesia practitioners that appropriate care of patients is also about ensuring appropriate postoperative recovery. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 18 anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 19 references 1. hukill sf, griffin sl. current attitudes related to the use of reversal agents after pharmacologic neuromuscular blockade [master’s thesis]. st. louis, mo: webster university; 2008. 2. plaud b. neuromuscular monitoring, residual blockade, and reversal: time for re-evaluation of our clinical practice. can j anaesth. 2013;60(7):634-640. http://dx.doi.org/10.1007/s12630-013-9952-4. 3. kopman af. neuromuscular monitoring: old issues, new controversies. j crit care. 2009;24(1):11-20. http:// dx.doi.org/10.1016/j.jcrc.2008.02.008. 4. kopman af, eikermann m. antagonism of non-depolarising neuromuscular block: current practice. anaesthesia. 2009;64:22-30. http://dx.doi.org/10.1111/j.1365-2044.2008.05867.x. 5. hemmerling tm, le n. brief review: neuromuscular monitoring: an update for the clinician. can j anaesth. 2007;54(1):58-72. http://dx.doi.org/10.1007/bf03021901. 6. donati f. residual paralysis: a real problem or did we invent a new disease? can j anaesth. 2013;60(7):714729. http://dx.doi.org/10.1007/s12630-013-9932-8. 7. murphy gs, brull sj. residual neuromuscular block: lessons unlearned. part i: definitions, incidence, and adverse physiologic effects of residual neuromuscular block. anesth anal. 2010;111(1):120-128. 8. brull sj, murphy gs. residual neuromuscular block: lessons unlearned. part ii: methods to reduce the risk of residual weakness. anesth anal. 2010;111(1):129-140. 9. welliver md, jones wh. interdisciplinary intraoperative communication and collaboration needed for optimal neuromuscular blockade management. j anaesth clin pharm. 2014;30(3):442-443. http://dx.doi. org/10.4103/0970-9185.137300. 10. neft m, quarashi ja, greenier e. a closer look at the standards for nurse anesthesia practice. aana j. 2013;81:92-96. 11. hunter j. antagonising neuromuscular block at the end of surgery. bmj. 2012 oct 15;345:e6666. doi: 10.1136/bmj.e6666. 12. lee pj, maclennan a, naughton nn, o’reilly m. an analysis of reintubations from a quality assurance database of 152,000 cases. j clin anesth. 2003;15(8):575-581. http://dx.doi.org/10.1016/j. jclinane.2003.03.006. the evolution of the adductor canal block: the emerging technique for motor-sparing analgesia to the knee jonathan p. kline, crna, m.s.n.a. keywords adductor canal, ultrasound, saphenous nerve block abstract this article summarizes current relevant data regarding the adductor canal block. it provides readers with background information of this emerging technique, including history, review of literature, relevant anatomy, and the technique itself. introduction the adductor canal block has recently gained attention from anesthesia and orthopedic communities. the desire to produce analgesia without the loss of motor control to the thigh seems to be beneficial. benefits of this technique may include shorter hospital stays, earlier and more efficient rehabilitation, and pain control. additionally, patients will retain the ability to report pain in neighboring distributions that can be involved when attempting to block the femoral nerve at the inguinal crease. this technique also embraces the emerging regional philosophy of selectivity or blocking only the area involved in the surgery. this article will review this novel technique. review of the literature was performed using keywords adductor canal block and saphenous nerve block. articles less than 5 years old were included, with the exception of one article which added historical context. aej history one of the earliest works leading to the development of the adductor canal block was done by van der wal and associates in canada.1 in their 1993 article, they established the block’s clinical viability utilizing cadavers. they described what they referred to as a “subsartorial approach” to the saphenous nerve blockade. their intent was to describe an alternative to a traditional landmark approach to the saphenous nerve block, primarily for foot and ankle procedures. this established a foundation for clinicians to incorporate a regional blockade of the saphenous nerve to provide analgesia for surgical knee procedures. review of literature horn and colleagues made a significant step forward in 2009 in the report titled “anatomic basis to the ultrasound-guided approach to the saphenous nerve blockade.”2 it is arguably the earliest work establishing the sonographic description of the block. in this article, the technique describes the close proximity under ultrasound of the saphenous nerve to the descending genicular artery. they showed this technique on cadavers in 2009. manickam and colleagues 3 were the first to link the technique of saphenous nerve blockade in the adductor canal for the purposes of knee joint analgesia. this publication described the blockade of the saphenous nerve in the adductor canal, bringing together the components in use today. these components are the placement of the probe at the mid-thigh, the ultrasound short-axis view description of the femoral artery and vein (as opposed to the descending genicular artery), the short-axis view of the sartorius, adductor longus, and magnus muscles, and the vastus medialis muscle. these findings were well-timed as sharma et al 4 drew the first association between femoral nerve blocks, commonly used for knee analgesia for knee surgery, and increased fall risk. this was the beginning of the push to establish a new technique that would spare the motor strength of the thigh muscles and find suitable alternatives to the femoral block which would reduce the risk of falls. in 2011, lund and colleagues 5 applied the concept of performing the adductor canal block for the purposes of analgesia after major knee surgery. the investigators introduced the first peri-neural catheters to the field of adductor canal mediated analgesia and established that 30 ml of local anesthetic would effectively fill the adductor canal. the same year, saranteas et al 6 investigated the efficacy of needle placement under ultrasound into the adductor canal, between the sartorius muscle and the femoral artery. this work demonstrated the saphenous nerve location between the femoral artery and sartorius muscle. of particular clinical significance was the conclusion that the saphenous nerve exits the adductor canal in over 80% of the population studied. also in 2011, karpoor and associates 7 spared the undesired muscle weakness of the femoral nerve block and implemented a saphenous nerve block in the adductor canal as an effective alternative approach. they demonstrated that in over 70% of the studied cadavers, the distal portion of the femoral nerve entered the vastus medialis muscle proximal to the location of the region which contains the saphenous nerve in a location anterior to the femoral artery. this portion of the femoral nerve innervates motor control of the vastus medialis muscle.7 this article added further information to the relatively elusive saphenous nerve location. in 2012, jaeger et al 8 conducted a proof-of-concept study which demonstrated a reduction in opioid requirement after total knee arthroplasty for study patients that received the block. additionally in 2012, jenstrup and colleagues 9 sought to establish a reduction of pain during a 45-degree flexion after knee surgery, reduce morphine consumption, and formally link muscle strength preservation by means of early ambulation. they were successful in all aspects, the most notable of which was the pain reduction at the 2 and 24 hour marks. henningsen and some of the original lund study investigators sought to show the incidence of saphenous nerve injury with the aej ultrasound-guided adductor canal block in 2013. they demonstrated that no patients suffered saphenous nerve injury from the ultrasonography (usg) technique and over 80% of patients had successful blocks.10 this study highlighted two important aspects of the technique; it established the technique’s safety and demonstrated that even under controlled conditions, it is not 100% effective. these results are consistent with other regional techniques investigation findings. in 2013, mudumbai et al 11 again investigated continuous peri-neural catheters to the usg adductor canal block. their results showed that compared with the same technique at the femoral nerve, patients ambulated farther distances postoperatively on days one and two. their findings additionally indicated analgesia was similar between groups that received either a femoral block or an adductor canal block. evolving the adductor canal block further as a means of preserving thigh muscle strength, jaeger and colleagues 12 again studied the effects of the block strictly compared to femoral nerve blocks. they showed, albeit on a small study population, that, in healthy volunteers, strength was preserved to nearly a state prior to having no block at all. this study suggests that the adductor canal block does allow for thigh muscle strength preservation and may therefore reduce fall risks for patients following knee surgery. in similar research, kwofie et al 13 enrolled slightly more volunteers, again studying the effect of the adductor canal block on quadriceps muscle strength and demonstrated similar results as the jaeger study on strength preservation. also in 2013, a headto-head, retrospective study comparing the analgesic/ambulatory effects of the adductor canal block to femoral nerve block was published by perlas et al 14 the authors quantitatively suggested that despite the femoral nerve block showing better analgesia, the strength loss in the quadriceps muscle was approximately 50%. they also demonstrated that an adductor canal block, plus local infiltration following surgery, was associated with earlier ambulation and strength preservation. in 2013, hanson et al 16 illustrated that the adductor canal block with ropivicaine was superior in reducing equivalent resting pain scores than the same block with saline in patients post-arthroscopic medial meniscectomy. investigating the adductor canal block in other surgical procedures, espelund et al 17 evaluated the efficacy of the block on patients post anterior cruciate ligament reconstruction in 2013. the study results failed to show any benefit of the block over intravenous (iv) non-steroidal anti-inflammatory medicines. this important study poses a question regarding the effect of the saphenous nerve innervation to this area of knee. another important factor which may affect block outcome is the block technique itself. previous studies show that the saphenous nerve is located on the medial side of the distal femoral artery. however, in the espelund study, the adductor canal block technique was approached from the lateral side of the artery. this approach required the local anesthetic to bathe the nerve from the infiltration entirely and negates the nerve’s natural position. additionally, all study blocks were performed after surgery. several researchers have demonstrated that regional anesthesia can inhibit the inflammatory cascade in a variety of locations.18,19,20,21,22 findings suggest that regional techniques of any kind may lower pain scores more effectively when done pre-procedurally. in 2013, andersen et al 23 studied the effects of an ultrasoundguided continuous peri-neural catheter technique on patients’ pain scores after total knee arthroplasty. the authors concluded that pain scores were significantly reduced in the group that received ropivicaine through the adductor canal catheter versus saline. an interesting caveat, all patients in the study received a spinal anesthetic as the primary route of anesthesia, and all catheters were placed postoperatively. this study design aej demonstrated two key outcomes: a reduction or elimination of the inflammatory response by implementing a regional technique prior to the generation of surgical pain and a postoperative catheter placement potentially improving block safety and efficacy. reduction in inflammatory response effect has been demonstrated in a number of different techniques whose validity will likely have a dramatic impact on the field of regional anesthesia. considerations for regional blockades utilizing catheter technique are that preoperative placement of catheters can be displaced by surgical manipulation or tourniquet compression to the thigh may result in catheter injury to underlying structures. relevant block anatomy the relevant anatomy for the adductor canal block focuses on the specific target of the saphenous nerve. the femoral nerve originates from the l-2 to l-4 spinal nerves. these l-2 through l-4 nerves join together as a structure known as the lumbar plexus. this plexus passes through the psoas compartment made of the psoas muscle posteriorly and the quadratus lumborum anteriorly. the femoral nerve emerges from under the inguinal canal and bifurcates into two smaller peripheral nerves in the anterior thigh.24 near the location of the superior third of the thigh, the femoral nerve continues its path deep into the leg to innervate the rectus femoris, vastus lateralis, vastus medialis, vastus intermedius, and sartorius. this group is primarily responsible for extending the lower leg and lifting the thigh forward and transferring weight during ambulation. the femoral nerve also sends off a pure sensory nerve called the saphenous nerve in the anterior thigh. the saphenous nerve separates from the femoral nerve and continues its path toward the knee accompanying the femoral artery and vein. this trio travels through the adductor canal. this canal is made up of the sartorius muscle superficially, and the vastus intermedius muscle as the deep component. the side wall completing a triangle is the adductor longus (see figure 1). within these three structures, a tunnel or canal is formed, allowing for passage of the saphenous nerve and the distal femoral artery and vein. the saphenous nerve is responsible for the sensory innervation of the anterior knee. it sends a sensory branch inferiorly to the region under the patella called the infrapatellar nerve. with this information, it seems logical that by blocking only the saphenous nerve, it is possible to cause analgesia to the anterior knee while preserving the anterior thigh motor control. technique there are a few techniques described for blocking the saphenous nerve selectively. advancing a needle blindly into the adductor canal was the first landmark-based technique, using the middle third of the inner thigh as the starting point. today, with the advances of ultrasound guidance, this is not recommended. the adductor canal’s relevant structures can be easily viewed with ultrasound. video: adductor canal ultrasound begin by slightly externally rotating the thigh. select a linear probe, and set the depth to around 4 cm. begin the scan by placing the probe in the midpoint of the patella and inguinal crease, on the medial side of the thigh. the probe should be positioned to allow for a short-axis view of the distal femoral artery. if in doubt of the artery’s identity, track the femoral artery path starting at the inguinal crease as in a femoral block or femoral vessel cannulation. once satisfied with the artery’s identity, place the adductor canal in view, with distal femoral artery in shortaxis visible. the doppler modes can be used to confirm the structures’ pulsatile flow. the sartorius and adductor longus should be easily visible (see figure 1). prep the needle insertion region with the institution’s antiseptic solution. for awake patients, advance a small gauge needle in plane through the projected needle path and deposit a fast-acting local anesthetic solution such as lidocaine or mepivacaine. once the needle path has been localized, advance a long blunt block aej needle under the artery. it is unlikely that the saphenous nerve will be visible but tilting the probe about 20-30 degrees away from the head can help. once the needle has arrived deep to the artery, aspirate and begin to deposit the local anesthetic block solution. redirect the needle in plane as necessary to fill the adductor canal. this volume will vary depending on a variety of factors, but one study showed that 30ml can fill the canal.5 figure 1. the relevant structures within the adductor canal summary the adductor canal block is in its infancy compared to other well-established regional techniques. in 2013, the greatest number of research articles on various aspects of the block was published. unlike other traditional techniques that seek to cause a sensory as well as a motor blockade, the adductor canal block attempts to spare the motor block of the neighboring distributions in an attempt to offer selective analgesia and strength preservation. a frequently asked question is “can the nerve stimulator be used as a secondary identifier for the saphenous nerve, either in combination or solo for saphenous nerve localization?” the answer seems to be that it can. although the saphenous nerve is a purely sensory nerve, the nerve stimulator is not without merit. however, sensory nerves do not elicit a motor twitch, so how then can this be explained? this is because although they have a higher rheobase† and † in this text, the rheobase is a physics term that describes the lowest electrical intensity required to elicit a nerve impulse. 26 chronaxie‡, they will elicit an appreciable response in awake patients. clinical electrical current settings for traditional motor twitch elicitation are between 0.2-1.0 ma. this avoids undesired sensory responses traditionally associated with stimulator settings above 1.0. these increased current settings above 1.0 ma produce sensory pulsations. these can be useful for sensory nerve localization.25 it should be noted that as current settings exceed 1.0 ma, there is an increased likelihood that the patient will complain of painful nerve pulsations. consequently, combining the nerve stimulator with ultrasound for nerve identity seems of some use, although not one study included in this article employed this technique. the majority of the recent studies2-5, 17 are optimistic that this relatively novel technique shows promise to accomplish the goal of knee analgesia and thigh strength preservation. although it is too early to be certain of its success, many of the various aspects regarding this technique have been cursorily reviewed. the research currently available is overwhelmingly positive, with only one reviewed study which did not demonstrate adductor canal block benefit over iv medications following knee arthroscopy. current understanding regarding the evolution of the adductor canal block, while limited, shows promise for this emerging technique to potentially address the issue of surgical knee pain analgesia and preservation of upper leg motor strength. author info jonathan p. kline, crna, m.s.n.a. director of education twin oaks anesthesia services, llc 26714 winged elm drive,wesley chapel, florida 33544 813-857-5559 / nerveblocker@gmail.com ‡ in this text, the chronaxie is a physics term describing the time needed that, doubling the rheobase, will elicit the same impulse. 26 aej references 1 van der wal m, lang sa, yip rw. transsartorial approach for saphenous nerve block. can j anaesth. 1993;40(6):542-546. 2 horn j, pitsch t, salinas f, et al. anatomic basis to the ultrasound-guided approach for saphenous nerve blockade. reg anesth pain med. 2009;34(5):486-489. 3 manickam b, perlas a, duggan e, et al. feasibility and efficacy of ultrasound-guided block of the saphenous nerve in the adductor canal. reg anesth pain med. 2009;34(6):578-580. 4 sharma s, iorio r, specht l, et al. complications of femoral nerve block for total knee arthroplasty. clin orthop relat res. 2010;468(1):135-140. published online august 13, 2009. doi: pmcid: pmc2795813. 5 lund j, jenstrup t, jaeger p, et al. continuous adductorcanal-blockade for adjuvant post-operative analgesia after major knee surgery: preliminary results. acta anaesthesiol scand. 2011;55:14–19. 6 saranteas t, anagnostis g, paraskeuopoulos t, et al. anatomy and clinical implications of the ultrasound-guided subsartorial saphenous nerve block. reg anesth pain med. 2011;36(4):399-402. 7 karpoor r, adhikary d, siefring c, et al. the saphenous nerve and its relationship to the nerve to the vastus medialis in and around the adductor canal: an anatomical study. acta anaesthesiol scand. 2012;56(3):365-367. 8 jaeger p, grevstad m, henningsen b, et al. effect of adductor-canal-blockade on established, severe post-operative pain after total knee arthroplasty: a randomized study. acta anaesthesiol scand. 2012;56(8):1013-1019. 9 jenstrup mt, jaeger p, lund j, et al. effects of adductorcanal-blockade on pain and ambulation after total knee arthroplasty: a randomized study. acta anaesthesiol scand. 2012;56(3):357-64. 10 henningsen mh, jaeger p, hilsted kl, et al. prevalence of saphenous nerve injury after adductor-canal-blockade in patients receiving total knee arthroplasty. acta anaesthesiol scand. 2013;57(1):112-117. 11 mudumbai sc, kim te, howard sk, et al. continuous adductor canal blocks are superior to continuous femoral nerve blocks in promoting early ambulation after tka. clin orthop relat res. 2013. published online july 2013. http://www.clinorthop.org/journals/online_first.html. last accessed nov 2013 12 jaeger p, neilsen z, henningsen mh, et al. adductor canal block versus femoral nerve block and quadriceps strength: a randomized, double-blind, placebo-controlled, crossover study in healthy volunteers. anesthesiology. 2013;118(2):409-415. 13 kwofie m, shastri u, gadsden j, et al. the effects of ultrasound-guided adductor canal block versus femoral nerve block on quadriceps strength and fall risk: a blinded, randomized trial of volunteers. reg anesth pain med. 2013;38(4):321-325. 14 perlas a, kirkham k, billing r, et al. the impact of analgesic modality on early ambulation following total knee arthroplasty. reg anesth pain med. 2013;38(4):334-339. 15 ilfield b, hadzic a. walking the tightrope after knee surgery: optimizing postoperative analgesia while minimizing quadriceps weakness. anesthesiology. 2013;118(2):248-250. 16 hanson n, derby r, auyong db, et al. ultrasound-guided adductor canal block for arthroscopic medial meniscectomy: a randomized, double-blind trial. can j anaesth. 2013;60(9):874-880. 17 espelund m, fomsgaard j, haraszuk j, et al. analgesic efficacy of ultrasound-guided adductor canal blockade after arthroscopic anterior cruciate ligament reconstruction: a randomised controlled trial. eur j anaesthesiol. 2013;30(7):422-428. aej 18 beilin b, bessler h, mayburd e, et al. effects of preemptive analgesia on pain and cytokine production in the postoperative period. anesthesiology. 2003;98:151-155. 19 freise h, daudel f, grosserichter c, et al. thoracic epidural anesthesia reverses sepsis-induced hepatic hyperperfusion and reduces leukocyte adhesion in septic rats. crit care. 2009;13:r116. 20 le bars d, adam f. nociceptors and mediators in acute inflammatory pain. ann fr anesth reanim. 2002;21:315-335. 21 sheeran p, hall gm. cytokines in anaesthesia. br j anaesth. 1997;78:201-219. 22 watkins lr, maier sf, goehler le. immune activation: the role of pro-inflammatory cytokines in inflammation, illness responses and pathological pain states. pain. 1995;63:289-302. 23 andersen h, gyrn j, moller l, et al. continuous saphenous nerve block as supplement to single-dose local infiltration analgesia for postoperative pain management after total knee arthroplasty. reg anesth pain med. 2013;38(2):106-111. 24 hadzic, a. chapter 35. in: texbook of regional anesthesia and acute pain management. new york, ny: mcgraw hill;2007:500. 25 hadzic, a. chaper 5. in: texbook of regional anesthesia and acute pain management. new york, ny: mcgraw hill;2007:94-98. 26 hadzic, a. chapter 5. in: texbook of regional anesthesia and acute pain management. new york, ny: mcgraw hill;2007:94-95. educated hand publishing llc “the science behind the art” volume 6 no. 7 2018 anesthesia ejournal online issn 2333-2611 page 33 safety of glucagon use during endoscopic retrograde cholangiopancreatography in patients with diabetes and renal insufficiency: case discussion and review of the literature lisa erlinger, phd, crna1 terri monk, md, ms2 steven mcafee, md3 affiliation: 1 assistant professor midwestern university-st. louis university, director of surgical and anesthesia services wickenburg community hospital 2. professor of clinical anesthesiology university of missouri-columbia 3. anesthesiologist university of missouri-columbia funding/conflict of interest disclosure: the authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements) or nonfinancial interest (such as personal or professional relationships, affiliations, knowledge, or beliefs) in the subject matter or materials discussed in this manuscript. no patient identifying information was used in this case report. keywords: endoscopic retrograde cholangiopancreatography, glucagon, diabetes, renal insufficiency, hyperkalemia abstract we describe the use of glucagon during endoscopic retrograde cholangiopancreatography (ercp) resulting in significant hyperkalemia. a 45-year-old man with physical classification 3 and type 1 diabetes mellitus, hypertension, and chronic kidney disease underwent ercp with general anesthesia for evaluation of a bile duct stricture. after intravenous administration of 0.75 mg glucagon (0.25-mg doses over 1 hour), tall, peaked t waves were noted on the electrocardiogram in lead ii. blood was collected and sent to the laboratory for evaluation. the patient’s potassium level was 6.6 meq/l and his glucose concentration was 568 mg/dl (31.5 mmol/l). calcium chloride 1000 mg was administered intravenously. his repeat potassium level was 6.1 meq/l and his repeat glucose concentration 393 mg/dl (21.8 mmol/l). the remainder of the procedure was uneventful and his postoperative potassium level was 5.2 meq/l. introduction endoscopic retrograde cholangiopancreatography (ercp) is a valuable diagnostic tool in the evaluation of pancreaticrelated diseases such as choledocholithiasis, benign and malignant strictures, and biliary tract disease. ercp was first introduced in the 1960s,1 and its use has steadily grown to approximately 500,000 cases per year in the united states, according to the last reported data from 2009.2,3 in the endoscopic portion of the examination, a side-viewing duodenoscope is passed through the esophagus and stomach into the second portion of the duodenum. the scope in this position can identify the major duodenal papilla and can be used to search for abnormalities. this structure is a projection of the hepatopancreatic ampulla (also known as the ampulla of vader) into the duodenal lumen. the ampulla of vader is the conjunction point of the ventral pancreatic duct and the common bile duct and thus acts as a conduit for drainage of bile and pancreatic excretions into the duodenum.4 the ampulla of vader contains the sphincter of oddi.5 cannulation can occur in either the common bile duct or the ventral pancreatic duct. once the duct is cannulated, either a cholangiogram (common bile duct) or a pancreatogram (pancreatic duct) is obtained fluoroscopically after injection of radiopaque contrast material into the duct. aej volume 6 no. 7 2018 anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 7 2018 page 34 insulin and glucagon are hormones secreted by islet cells within the pancreas. each counterbalances blood glucose levels to keep the body within the normal therapeutic range. one of the many functions of insulin is to decrease blood glucose by moving glucose into cells. glucagon is released into the circulation when blood glucose is too low, increasing plasma glucose levels. this maintains homeostasis in the body and keeps blood glucose stable.6 glucagon (rdna origin) for injection (glucagen; novo nordisk a/s) is produced by expression of recombinant dna in a saccharomyces cerevisiae vector with subsequent purification. glucagon for injection is an anti-hypoglycemic agent and inhibits gastrointestinal motility. hepatic stores of glycogen are necessary for glucagon to produce an anti-hypoglycemic effect.7 glucagon induces liver glycogen breakdown, releasing glucose from the liver. blood glucose concentrations rise within 10 minutes of injection, and peak concentration is attained approximately 30 minutes after injection. glucagon also inhibits gastrointestinal motility by relaxation of the smooth muscles. the administration of sphincter-relaxing agents, like glucagon, enables the endoscopist to extract small, common bile duct stones without performing a papillotomy.8 a papillotomy is performed by cutting the ampulla of vater to widen its outlet to improve bile drainage and allow the passage of stones from the common bile duct. glucagon decreases the frequency and amplitude of phasic activity of the sphincter of oddi.8-10 intravenous glucagon is often used during ercp to inhibit duodenal motility and enhance cannulation. however, glucagon can cause significant side effects, including nausea and vomiting, hyperglycemia, and hyperkalemia in patients with diabetes.11 case summary a 45-year-old man weighing 61 kg with a body mass index of 22 presented for an ercp with cholangiogram. three months before the procedure, he had undergone a laparoscopic cholecystectomy with intraoperative cholangiogram. during this initial procedure, it was noted that he had a common bile duct stricture. the pathology results at that time revealed a high-grade dysplasia of the cystic duct stump. he was recommended to undergo further evaluation with an ercp with common bile duct brushings and biopsies. the patient’s medical history included a 30-year history of type 1 diabetes mellitus, chronic kidney disease, hypertension, hyperlipidemia, and a 20-pack-year smoking history. preoperative laboratory results revealed a creatinine level of 2.6 mg/dl (230 µmol/l) and a glycated hemoglobin (hba1c) value of 10.4%. he was taking insulin glargine (lantus), 20 units subcutaneously at bedtime, and using an insulin lispro (humalog) sliding scale regimen during the day with an average use of 40 units daily. his diabetes was poorly controlled with daily blood glucose values ranging from 200 to 300 mg/dl (11.1-16.6 mmol/l. his preoperative vital signs were blood pressure of 130/88 mm hg and heart rate of 90 beats per minute. he had not taken any medications on the day of surgery. his preoperative fasting blood glucose concentration was 160 mg/dl (8.9 mmol/l) and his potassium level was 4.9 meq/l. general anesthesia was induced intravenously with 100 µg fentanyl, 100 mg lidocaine, and 100 mg propofol. after administration of 100 mg succinylcholine, the patient was orally intubated and anesthesia was maintained with sevoflurane to maintain approximately 1 minimum alveolar concentration. the video gastroduodenoscope was advanced to the second part of the duodenum and an attempt was made to cannulate the common bile duct. intravenous (iv) glucagon 0.25 mg was requested by the gastroenterologist to relax the common bile duct. this dose was repeated twice over the next 30 minutes. after the third dose, tall, peaked t waves were noted on the electrocardiogram (ecg), an acute change from the normal ecg at the start of the procedure. the patient’s blood was drawn and sent to the laboratory and the findings revealed a potassium level of 6.6 meq/l and a glucose concentration of 568 mg/dl (31.5 mmol/l). calcium chloride 1000 mg iv was administered over 10 minutes with improvement in the ecg shown as a decrease in amplitude of the peaked t waves. four puffs of nebulized albuterol were also administered via the endotracheal tube. repeat measurements of electrolytes conducted 30 minutes later showed a potassium level of 6.1 meq/l and a glucose concentration of 393 mg/dl (21.8 mmol/l). calcium chloride 1000 mg iv was administered over 10 minutes with improvement in the ecg shown as a decrease in amplitude of the peaked t waves. four puffs of nebulized albuterol were also administered via the endotracheal tube. repeat measurements of electrolytes conducted 30 minutes later showed a potassium level of 6.1 meq/l and a glucose concentration of 568 mg/ dl (11.1 mmol/l). the procedure was completed, the patient was extubated without incident, and he was monitored in the post-anesthesia care unit for 2 hours. repeat measurements of electrolytes showed a potassium level of 5.2 meq/l and a glucose concentration of 505 mg/dl (28.0 mmol/l). the patient was transferred to the intensive care department for glucose management. discussion normally, hyperkalemia elicits its own “self-treatment.” this is done automatically by the body with endogenous glucose and insulin release, insulin-increasing potassium tolerance, and endogenous glucagon, which provides enough glucose to prevent hypoglycemia.11 this self-regulation allows for administration of glucagon in a nondiabetic patient to result in inconsequential increases in glucose or potassium. however, as far back as 1973, a study by santeusanio et al12 raised the possibility of hyperglucagonemia in diabetic ketoacidosis. santeusanio et al had an incidental finding of clinical relevance. they warned that patients with diabetic ketoacidosis are at increased risk of developing hyperkalemia. this risk is increased if patients are administered potassium or encounter a stressful condition because endogenous insulin responsiveness is impaired by hypercatecholaminemia. they suggested that the risk may be excessive unless affected insulin action has been established, particularly in patients with kidney disease. similarly, massara et al13 investigated the role played by glucagon in the regulation of plasma potassium. they found low blood insulin and increased glucagon could be one of the mechanisms that trigger or magnify the hyperkalemia observed in cases of severe stress for patients with decompensated diabetes. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 7 2018 page 35 christensen et al14 explored factors that affect the variability in heart rate during ercp. the researchers divided the volunteers into 3 groups. each group received an administration of butylscopolamine, glucagon, or saline, and the researchers looked for myocardial ischemia and changes in the variability of heart rate. two patients in the butylscopolamine-free group developed ischemia, resulting in unexplained pathophysiologic changes.14 the st segment depressions in the christensen et al study lasted 226 s and 550 s, respectively. could this be the result of transient hyperkalemia from glucagon? no further information was given concerning patient histories to make any conclusions for practice. tall, peaked t waves are findings of concern in the perioperative setting, particularly, as in this case, when they represent a change from the patient’s baseline. the differential diagnosis of prominent t waves can include hyperkalemia, myocardial ischemia, left ventricular hypertrophy, benign early repolarization, bundle branch block, pericarditis, and normal variant, especially in the young.15 hyperkalemia or myocardial ischemia was most likely the cause in this case, because the t wave elevation developed as an acute change from the start of the procedure. the laboratory evaluation confirmed that hyperkalemia was the diagnosis. the treatment of acute hyperkalemia included administration of calcium chloride iv to stabilize the cardiac membrane from potentially fatal arrhythmias. the recommended dose is 10 to 20 ml of a 10% calcium chloride solution and a ß-adrenergic agonist such as nebulized albuterol to redistribute extracellular potassium into the cells. a sodium bicarbonate–glucose-insulin mixture could also have been used. sodium bicarbonate 0.5-1.0 meq/ kg iv shifted potassium intracellularly while the glucose-insulin infusion (50 ml of 50% glucose plus 10 units regular insulin) produced a sustained transfer of extracellular potassium into the cells. therapeutic agents could also have been administered to lower the total body potassium. polystyrene compounds (kayexalate) or loop-diuretics both increase potassium excretion via gastrointestinal and renal systems, respectively. this case demonstrates the importance of considering alternative means of duodenal antiperistalsis and sphincter of oddi relaxation to allow for ampullar cannulation in patients with diabetes and/or chronic kidney disease undergoing ercp. one such agent is l-hyoscyamine, an anti-cholinergic, anti-muscarinic alkaloid that is frequently administered via the sublingual route. a review of the literature did not support widespread use of l-hyoscyamine. l-hyoscyamine is associated with periprocedural adverse effects including nausea and vomiting and has not been shown to decrease the amount of glucagon patients receive.11,16 perhaps a better strategy would be to minimize the use of glucagon in patients with diabetes at elevated risk for hyperkalemia. conclusion this is the first report of acute hyperkalemia during ercp. although rare, this complication can be life-threatening if not recognized and immediately treated. in nondiabetic patients, glucagon administration causes a modest increase in plasma potassium levels, but these effects are magnified in patients with diabetes, especially in individuals who are insulin deficient or have a history of uncontrolled diabetes. the anesthesia provider should be aware of the possibility of hyperkalemia during ercp and its effects on the myocardium. it is important to formulate a suitable approach to the management of hyperkalemia during ercp. it may be prudent to check serum potassium and blood glucose in all patients with diabetes, especially those with chronic kidney disease. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 7 2018 page 36 references 1.  mccune ws, shorb pe, moscovitz h. endoscopic cannulation of the ampulla of vater: a preliminary report. ann surg. 1968;167(5):752-756. https://doi.org/10.1097/00000658-196805000-00013. 2.  puig i, calvet x, baylina m, et al. how and when should nsaids be used for preventing post ercp pancreatitis? a systematic review and meta analysis. plos one. 2014;9(3):e92922. https://doi.org/10.1371/journal.pone.0092922. 3.  moffatt dc, yu bn, yie w, bernstein cn. trends in utilization of diagnostic and therapeutic ercp and cholecystectomy over the past 25 years: a population based study. gastrointest endosc. 2014;79(4):615-622. https://doi.org/10.1016/j. gie.2013.08.028. 4.  malas a, roberts k. endoscopic retrograde cholangiopancreatography: overview, periprocedural care, technique. medscape. https://emedicine.medscape.com/article/1829797-overview. published may 13, 2015. accessed september 12, 2015. 5.  endoscopic retrograde cholangiopancreatography (ercp), institute for cancer genetics and informatics. youtube. https:// youtu.be/irda2krj6lq. published september 13, 2013. accessed november 19, 2016. 6.  muller td, finan b, clemmensen c, dimarchi rd, tschop mh. the new biology and pharmacology of glucagon. physiol rev. 2017;97(2):721-766. https://doi.org/10.1152/physrev.00025.2016. 7.  physicians’ desk reference. montvale, nj: thomson pdr; 2014. 8.  staritz m. pharmacology of the sphincter of oddi. endoscopy. 1988;20(s 1):171-174. https://doi. org/10.1055/s-2007-1018170. 9.  rey jf, greff m, picazo j. glucagon (1-21) peptide. study of its action on sphincter of oddi function by endoscopic manometry. dig dis sci. 1986;31(4):355-360. https://doi.org/10.1007/bf01311669. 10.  ponce j, garrigues v, pertejo v, et al. effects of intravenous glucagon-(1-21)-peptide on motor activity of sphincter of oddi in humans. dig dis sci. 1989;34(1):61-64. https://doi.org/10.1007/bf01536155. 11.  lahoti s, catalano mf, geenen je, hogan wj. a prospective double blind trial of l-hyoscyamine versus glucagon for the inhibition of small intestinal motility during ercp. gastrointest endosc. 1997;46(2):139-142. https://doi.org/10.1016/s00165107(97)70061-0. 12.  santeusanio f. evidence for a role of endogenous insulin and glucagon in the regulation of potassium homeostasis. j lab clin med. 1973;6:81. 13.  massara f, martelli s, cagliero e, camanni f, molinatti gm. influence of glucagon on plasm levels of potassium in man. diabetologia. 1980;19(5):414-417. https://doi.org/10.1007/bf00281818. 14.  christensen m. factors that affect the variability in heart rate during endoscopic retrograde cholangiopancreatography. eur j surg. 2002;168:546-551. 15.  somers mp, brady w, perron a, mattu a. the prominent t wave: electrocardiographic differential diagnosis. am j emerg med. 2002;20(3):243-251. https://doi.org/10.1053/ajem.2002.32630. 16.  lynch cr, khandekar s, lynch sm, disario ja. sublingual l-hyoscyamine for duodenal antimotility during ercp: a prospective randomized double-blinded study. gastrointest endosc. 2007;66(4):748-752. https://doi.org/10.1016/j. gie.2007.02.052. volume 7no. 2 2019 educated hand publishing llc “the science behind the art” volume 7 no. 2 2019 anesthesia ejournal online issn 2333-2611 page 5 use of clevidipine as an alternative to nitroglycerin in cardiac surgery: case report and current literature kate cloud, dnp, crna monica jenschke, phd, crna affiliation: school of nurse anesthesia at texas christian university funding/conflict of interest disclosure: none keywords: clevidipine, nitroglycerin, hypotension, anesthesia, perfusion introduction this report summarizes a case of tachyphylaxis to nitroglycerin that occurred intraoperatively during cardiac surgery in a patient in whom therapeutic hypotension was being induced. the anesthesia providers were prepared with an ample supply of nitroglycerin and had other antihypertensive agents such as hydralazine, labetalol, and esmolol available in the operating room. however, the ideal medication for inducing therapeutic hypotension and most similar to nitroglycerin in its ability to create rapid-onset, transient hypotension, ie, clevidipine, was not readily available. the therapeutic hypotension had been requested by the surgeon for surgical optimization; thus, the patient experienced no harm despite the lack of expected response to nitroglycerin and delay in onset of therapeutic hypotension. however, the anesthesia providers recognized the need to avoid similar hemodynamic delays, particularly in less forgiving scenarios in which timing is crucial. abstract cardiac surgery requires periods of therapeutic hypotension. anesthesia providers often administer intravenous nitroglycerin to accomplish these meticulous hemodynamic goals. however, patients can manifest adverse responses to nitroglycerin, such as decreased stroke volume; decreased cardiac output; decreased renal, splanchnic, and cerebral perfusion; and tolerance. this report summarizes a case of tachyphylaxis to nitroglycerin that occurred intraoperatively in a patient undergoing cardiac surgery in whom therapeutic hypotension was being induced. in situations such as this, an alternative medication is needed that is just as effective and safe. clevidipine is currently the best choice for this because of its rapid onset and termination of action and specific arterial effects. multiple studies have shown that clevidipine is as effective and safe as nitroglycerin. aej anesthesia ejournal www.anesthesiaejournal.com volume 7 no.2 2019 page 6 case summary a 70-year-old man presented for off-pump coronary artery bypass grafting (cabg) surgery. the patient was 170 cm tall, weighed 89 kg, had a body mass index of 31, and received a physical status indicator of 4. he denied any drug allergies. aspirin 81 mg orally twice a day was his only home medication. however, his medical history included hypertension, coronary artery disease, angina with exertion, peripheral vascular disease, chronic obstructive pulmonary disease, osteoarthritis, degenerative disc disease, vertigo, and an asymptomatic infrarenal abdominal aortic aneurysm. the patient quit smoking 10 years ago, and reported alcohol consumption 3 times per week. a chest x-ray showed signs of mild emphysema, and the patient’s lungs were clear to auscultation bilaterally. a 2d echocardiogram revealed mild concentric hypertrophy of the patient’s heart, left ventricular diastolic dysfunction, and an ejection fraction of about 55%-65%. heart tones were regular to auscultation. preoperative laboratory results included a hemoglobin of 14 g/ dl, hematocrit of 44%, creatinine of 0.9 mg/dl, and potassium of 4.3 meq/l. airway assessment showed the patient to have full range of motion of his neck, interincisor distance of 3 cm, temporomandibular distance of 3 cm, and a mallampati score of 2. general anesthesia was induced with midazolam 5 mg intravenous (iv), sufentanil 50 mcg iv, propofol 150 mg, and inhaled sevoflurane. the patient also received vecuronium 10 mg iv. the airway was secured with an 8-mm endotracheal tube. acetaminophen 1000 mg and cefazolin 2 g were given as iv infusions. a central venous introducer and pulmonary artery catheter were placed. transesophageal echocardiography (tee) was performed. the mediastinum was accessed via midline sternotomy, and the surgeon began to harvest the internal mammary artery and tack up the pericardium. when the heart was manipulated for off-pump grafting, the pulmonary arterial systolic pressure increased suddenly from 30 mm hg to 80 mm hg. st segment changes were noted per electrocardiogram, and tee revealed hypokinesis of the lateral wall of the heart. the decision was made to abort the off-pump attempt at grafting and to initiate cardiopulmonary bypass (cpb) to complete the procedure. nitroglycerin was administered in 40-80 mcg intermittent iv boluses to maintain systolic blood pressure (bp) at less than 100 mm hg during placement of the aortic cannula. milrinone infusion was started at 0.375 mcg/kg/min. cpb was initiated and mean arterial pressure was maintained at or greater than 60 mm hg. the grafts were completed, and the patient was weaned from cpb. when it was time to remove the aortic cannula, the surgeon requested a systolic bp less than 100 mm hg. nitroglycerin 200 mcg was given intravenously. the systolic bp changed from 147 mm hg to 144 mm hg. nitroglycerin 400 mcg iv was given. the systolic bp then decreased to 131 mm hg. nitroglycerin 1400 mcg iv was given, and the systolic bp decreased to 120 mm hg. minutes passed and the surgeon still waited to remove the aortic cannula. sufentanil 50 mcg iv and vecuronium 4 mg iv were given at that point. nitroglycerin was attempted again, in a dose of 2000 mcg iv. the systolic bp remained at 124 mm hg. another dose of nitroglycerin 2000 mcg iv was given, and the systolic bp decreased to 111 mm hg. nitroglycerin 2000 mcg iv was repeated, and the systolic bp decreased to 103 mm hg. the aortic cannula was then removed without complications. seven minutes had passed since the surgeon’s initial request for systolic bp less than 100 mm hg. the surgical site was closed and the patient was transported to the intensive care unit with stable vital signs. discussion the patient’s lack of hemodynamic response to iv nitroglycerin during this case was unexpected. it was also unprecedented, as the patient had responded to the nitroglycerin earlier in the case. by definition, this was a case of tachyphylaxis: rapidly developed desensitization to the therapeutic effects of the medication. nitroglycerin tolerance was ruled out, because tolerance would have required development over a longer period of time during which nitrates were administered consistently. fortunately, the surgeon’s request for a decrease in bp was a matter of surgical optimization rather than a matter of life or death for the patient. however, iv nitroglycerin is a drug that anesthesia providers rely on during episodes of hemodynamic crisis in the operating room. failure of hemodynamic response to nitroglycerin, coupled with lack of an alternative antihypertensive readily available could be detrimental to the patient. therefore, an alternative antihypertensive should be chosen before initiation of the surgical procedure and should be readily available throughout the case. while there are many options for iv antihypertensive therapy, current literature reports many benefits to the use of clevidipine. clevidipine has fast onset and termination of action times similar to those of nitroglycerin that make it an appealing alternative therapy. a literature search was conducted through the embase (elsevier), medline (national library of medicine), and web of science databases using the terms nitroglycerin, clevidipine, tolerance, tachyphylaxis, and mechanism of action. current literature nitroglycerin is an organic nitrate that can be administered sublingually or intravenously. it causes dilation of peripheral veins and large coronary arteries. these mechanisms yield decreased venous return and preload, decreased myocardial wall tension, decreased myocardial oxygen demand, and improved myocardial oxygen supply. nitroglycerin does not cause dilation of small coronary vessels, which helps to prevent coronary steal syndrome. nitroglycerin also causes a slight decrease in platelet aggregation. these characteristics make nitroglycerin ideal for the treatment of patients with coronary artery disease. intraoperatively, iv nitroglycerin can be used for rapid yet meticulous bp management. it acts within seconds after administration, and the medication effects last only 3 to 5 minutes, allowing for the quick changes in bp that are often required in vascular surgeries. in cabg procedures that use cardiopulmonary bypass, 2 specific moments require a normal but low systolic bp to prevent dissection or bleeding from the aorta: 1) aortic cannulation and 2) removal of the aortic cannula. these procedures occur at the very beginning and the very end of cpb, respectively. anesthesia providers routinely use nitroglycerin at these times to adjust the bp to the surgeon’s requested level. although this technique is effective for most patients, some patients have tolerance to organic nitrates such as nitroglycerin. the mechanism of tolerance to organic nitrates is currently anesthesia ejournal www.anesthesiaejournal.com volume 7 no. 2 2019 page 7 unspecified. nitroglycerin undergoes complex biotransformation upon administration, making it difficult to identify a single source of tolerance. nitroglycerin can be considered a prodrug; it is metabolized to yield nitric oxide (no), the actual substance that stimulates smooth muscle cell relaxation. after administration of nitroglycerin or another organic nitrate, no is formed in healthy vascular endothelium from l-arginine by endothelial nitric oxide synthase (enos). no then activates soluble guanylyl cyclase (sgc), which increases levels of cyclic guanosine monophosphate (cgmp). cgmp has multiple effects that ultimately cause a decrease in intracellular calcium, which inhibits myosin activity, and thereby leads to vascular smooth muscle cell relaxation. this effect may appear clinically as decreased bp or improved myocardial oxygenation. however, if a patient is tolerant to organic nitrates, these expected effects will not occur. tolerance to organic nitrates develops in the presence of nitrate therapy lasting 24 hours or longer. the result is a lack of response to subsequent doses of nitrates. this tolerance dissipates rapidly in the absence of organic nitrates and can therefore be avoided by daily pauses in nitrate therapy. in contrast, tachyphylaxis develops rapidly after initial administration of a drug. it may occur within minutes to hours of administration. a key characteristic of tachyphylaxis is diminishing response to the medication despite increased doses. eventually, there may be no noticeable response to the medication. tachyphylaxis after administration of intravenous nitroglycerin is rare, and the cause is unknown. it is possible that tachyphylaxis is caused by similar mechanisms proposed for tolerance to organic nitrates but in an accelerated timeframe. or nitroglycerin tachyphylaxis may be due to something completely different. regardless, tachyphylaxis is by nature unexpected. therefore, the primary goal for anesthesia providers is to be prepared at all times with an alternative treatment for the patient, should the initial treatment fail. current literature indicates that clevidipine is a good alternative in this situation. new treatments to induce hypotension clevidipine is a dihydropyridine, l-type, vasoselective calcium channel blocker. due to this composition, clevidipine blocks intracellular calcium influx in arterial vasculature only, not in veins. therefore, administration of clevidipine leads to decreased systemic vascular resistance, decreased bp, and increased stroke volume. these effects allow for a decrease in myocardial oxygen demand. unlike nitroglycerin, venous beds are not dilated, and so venous return and preload remain constant, allowing for maintenance of cardiac output. clevidipine has a rapid onset and produces effects within 1 minute. termination of clevidipine action is also rapid. plasma esterases hydrolyze clevidipine, and the effects are almost completely terminated within 5 minutes. the metabolites produced by ester hydrolysis are most likely excreted via biliary and intestinal tracts. because metabolism remains independent from both renal and liver function, clevidipine can be administered to patients with renal or liver impairment. this ester hydrolysis metabolism is dependent on the temperature of the patient’s body, however. the deliberate hypothermia used during cpb reduces the metabolism of clevidipine to just half of the regular rate of metabolism. clevidipine is prepared as a lipid emulsion in soybean oil. at steady state, the volume of distribution is 0.6 l/kg. clevidipine is also highly protein bound. it has been found to help reduce ischemia in renal, splanchnic, and myocardial tissues during reperfusion. no tolerance to clevidipine has been reported in the published literature to date. summary overall, nitroglycerin and clevidipine have many similarities: protection against reperfusion injury, rapid onset and offset, and decreased bp. however, the mechanism of action of each of these drugs is distinct and is the basis of therapeutic decisions in the clinical setting. of these 2 drugs, nitroglycerin administration is most likely to result in adverse hemodynamics or tolerance and lack of effectiveness. therefore, while nitroglycerin is still useful during cardiovascular procedures, clevidipine must also be readily available. anesthesia ejournal www.anesthesiaejournal.com volume 7 no. 2 2019 page 8 references 1. divakaran s, loscalzo j. the role of nitroglycerin and other nitrogen oxides in cardiovascular therapeutics. j am coll cardiol. 2017;70(19):2393-409. doi:10.1016/j.jacc.2017.09.1064. 2. mayer b, beretta m. the enigma of nitroglycerin bioactivation and nitrate tolerance: news, views and troubles. br j pharmacol. 2008;155:170-84. doi:10.1038/bjp.2008.263. 3. hegde hv, jagadish n, rao pr. an ultra-rapid development of tachyphylaxis to nitroglycerin. indian j anaesth. 2014;58(6):777-8. doi:10.4103/0019-5049.147183. 4. nordlander m, sjöquist po, ericsson h, rydén l. pharmacodynamic, pharmacokinetic and clinical effects of clevidipine, an ultrashort-acting calcium antagonist for rapid blood pressure control. cardiovasc drug rev. 2004;22(3):227-50. pmid:15492770. 5. espinosa a, ripollés-melchor j, casans-francés r, et al; evidence anesthesia review group. perioperative use of clevidipine: a systematic review and meta-analysis. plos one. 2016;11(3):e0150625. pmid:27018586. 6. aronson s, dyke cm, stierer ka, et al. the eclipse trials: comparative studies of clevidipine to nitroglycerin, sodium nitroprusside, and nicardipine for acute hypertension treatment in cardiac surgery patients. anesth analg. 2008;107(4):111021. pmid:18806012. 7. merry af, avery eg, nussmeier na, et al. clevidipine compared with nitroglycerin for blood pressure control in coronary artery bypass grafting: a randomized double-blind study. can j anaesth. 2014;61(5):398-406. pmid:24700403. 8. katzung bg, trevor aj, eds. basic & clinical pharmacology. 13th ed. new york, ny: mcgraw hill education; 2015. volume 6 no. 8 2018 educated hand publishing llc “the science behind the art” volume 6 no. 8 2018 anesthesia ejournal online issn 2333-2611 page 37 opioid-free anesthesia for an emergency laparoscopic cholecystectomy in a patient taking buprenorphine-naloxone for opioid addiction: a case report thomas baribeault, msn, crna affiliation: founder of society for opioid-free anesthesia and chief crna at lexington surgery center funding/conflict of interest disclosure: no grants or financial support were used in this paper acknowledgments jennifer holmes, els, is acknowledged for medical writing support keywords:opioid-free anesthesia, buprenorphine-naloxone, pain management, opioid addiction, anesthesiology abstract with the growing public health problem of opioid misuse, addiction, and overdose, the number of patients presenting for surgery and anesthesia who may be opioid-dependent or undergoing medication-assisted treatment for opioid use disorder is increasing. these patients may be appropriate candidates for opioid-free anesthesia. this case report describes a patient being treated with buprenorphine-naloxone for opioid addiction who required an emergency laparoscopic cholecystectomy. she requested that opioids not be used in her treatment plan. the patient’s pain was successfully managed with opioid-free anesthesia and she was discharged with no requirement for additional pain medications. introduction opioid misuse, addiction, and overdose are growing public health problems. in 2016 alone, 11.5 million persons aged 12 or older in the united states misused prescription pain relievers.1 according to recent data from the centers for disease control and prevention, the rate of drug overdose deaths involving synthetic opioids other than methadone (eg, fentanyl, fentanyl analogs, and tramadol) doubled from 2015 to 2016 (from 3.1 to 6.2 per 100,000 persons).2 as the number of prescriptions written for opioid pain medication rises, so too does the number of patients presenting for surgery and anesthesia who may be opioid-dependent or undergoing medication-assisted treatment for opioid use disorder. buprenorphine combined with naloxone (suboxone) is used to treat opioid dependence in outpatient settings. buprenorphine is a mu-opioid receptor partial agonist and a kappa-opioid receptor antagonist, and naloxone is an opioid receptor antagonist. by binding to the mu-opioid receptor, buprenorphine mimics the pharmacological effect of an opioid but to a lesser extent, thus preventing opioid withdrawal symptoms.3 however, the high receptor binding affinity and long half-life of buprenorphine make it difficult to treat acute pain in patients being treated for opioid addiction.4 in the present case, a patient who was being treated for opioid addiction required an emergency laparoscopic cholecystectomy. she requested that opioids not be used in her treatment plan. this report describes the successful delivery of opioid-free anesthesia to a patient being treated with buprenorphine-naloxone. aej anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 8 2018 page 38 case summary a 29-year-old woman (height, 67”; weight, 61 kg; ps2) presented to the emergency department with acute cholecystitis. she had a history of thyroid cancer that had been treated by thyroidectomy, current tobacco abuse, social alcohol use, and a history of opioid abuse currently being treated with buprenorphine-naloxone (suboxone; indivior). preoperative vital signs included a blood pressure of 116/74, heart rate of 82, respiratory rate of 18, oxygen saturation of 95% on room air, and temperature of 100.6 degrees fahrenheit. during the anesthesia interview, the patient discussed her concerns both with relapse as a result of receiving opioids for pain and with having uncontrolled pain after surgery because of her buprenorphine-naloxone treatment. because of the emergent nature of the case, there was no time to involve the buprenorphine-naloxone provider in the discussion or to delay surgery until the buprenorphine-naloxone had worn off. the patient and anesthetist discussed a plan of care including multimodal therapy, reasonable expectations after surgery, and acceptable pain levels. the patient gave verbal consent to publication of the case. no approval was sought from an ethics committee because of the emergent nature of the case; the writing of the report did not change the care the patient received. the patient was taken to the operating room and general anesthesia was induced with 150 mg propofol, 100 mg lidocaine, 50 mg ketamine, and 100 mcg clonidine. intubation was facilitated with 50 mg rocuronium, which also provided the necessary muscle relaxation for laparoscopic surgery. during induction, a second certified registered nurse anesthetist (crna) performed bilateral subcostal transversus abdominis plane (tap) blocks with 30 ml 0.25% bupivacaine and 5 mg preservative-free dexamethasone per side shortly after intubation. the case proceeded uneventfully and lasted 132 minutes during which general anesthesia was maintained with desflurane 4% to 5%. the patient required 50 mg ephedrine in divided doses throughout the case to maintain mean arterial pressure (map) > 70. the heart rate varied between 60 and 80 beats/min, respiratory rate was set at 15 breaths/min on the ventilator, and oxygen saturation was 98% to 100%. the temperature was 100.6 degrees fahrenheit and decreased to 99.0 degrees fahrenheit by the time the procedure was over. two additional 10-mg boluses of rocuronium were required for muscle relaxation. the patient received 8 mg dexamethasone before incision and 4 mg ondansetron on emergence for nausea prophylaxis. the patient was also given 1 g acetaminophen (ofirmev; mallinckrodt) and 30 mg ketorolac intravenously on emergence for postoperative pain. in addition, 3 mg neostigmine and 0.4 mg glycopyrrolate was given for muscle relaxant reversal. at the conclusion of the case, the patient was extubated and taken to the post-anesthesia care unit (pacu). on admission to the pacu, she was drowsy but awake and alert and fully oriented to person, place, date, and time with stable vital signs. she had mild pain but at an acceptable level (visual analogue scale <4/10) and did not wish to try and reduce her pain through opioid medications. after a suitable period of recovery, she was discharged with no requirement for additional pain medications. discussion in this case, the anesthetist addressed the patient’s anxiety about pain and relapse by providing opioid-free anesthesia. fear of postsurgical pain and the ubiquitous prescribing of opioids for the treatment of acute pain can be strong triggers for relapse in patients being treated for addiction.4 patients should be reassured that a history of addiction will not be a barrier to the adequate treatment of postoperative pain.5 patients can also be encouraged to intensify their involvement in a recovery program after surgery to help to prevent stress-mediated relapse.5 the availability of buprenorphine and buprenorphine-naloxone has expanded opportunities for outpatient treatment of opioid addiction. however, treatment of these patients in the perioperative setting is challenging. although consensus on the perioperative management of patients taking buprenorphine is lacking, regional and systemic opioid-sparing treatments should be used whenever possible.4 therapeutic options include alternative routes of administration of local anesthetic agents, infusion of ketamine, and regional anesthesia.6 nonopioid analgesics can be used initially for postoperative pain with or without continuous regional local anesthesia or selective nerve blocks.5 in this case, the patient received multimodal therapy including regional anesthesia and nonopioid analgesics for postoperative pain. the guidelines for the management of postoperative pain of the american pain society, the american society of regional anesthesia and pain medicine, and the american society of anesthesiologists’ committee on regional anesthesia, executive committee, and administrative council recommend that clinicians offer multimodal anesthesia to treat postoperative pain in both children and adults.7 the rationale for multimodal anesthesia is that by administering different analgesic medications that target different mechanisms of action in the nervous system, better pain management can be achieved by blocking receptors both centrally and peripherally. the results of randomized trials have shown that multimodal anesthesia is associated with improved pain relief and decreased opioid consumption.7 the multimodal anesthesia plan in this case included ketamine, clonidine, ketorolac, acetaminophen, and regional anesthesia. nonopioid analgesic agents were given on emergence. postoperative pain guidelines recommend the consideration of ketamine as a component of multimodal analgesia.7 when included in a multimodal regimen, clonidine has been shown to be effective for reducing acute postoperative pain and progression to chronic pain.8 in this case, acetaminophen and ketorolac were given intravenously on emergence. the classes of nonopioid analgesics that can be considered in this population for acute pain include acetaminophen, nonsteroidal anti-inflammatory drugs, n-methyl-d-aspartate (nmda) receptor antagonists, alpha-2 agonists, gabapentinoids, and selective serotonin reuptake inhibitors.4 the patient in this case, a woman aged less than 20 years, undergoing general anesthesia, and possibly needing postoperative opioids, had characteristics that placed her at higher risk for postoperative nausea and vomiting (ponv). in addition to reducing postoperative opioid use, multimodal therapies can significantly reduce the incidence of ponv.8 patients undergoing bariatric surgery are also at high risk for ponv. in a small prospective, randomized study of patients undergoing elective bariatric surgery, ziemann-gimmel et al reported that opioidfree anesthesia with dexmedetomidine significantly reduced the risk of developing ponv.9 anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 8 2018 page 39 opioid-free anesthesia is a relatively new trend in anesthesia administration. as the united states continues to address the opioid epidemic, anesthesiologists will encounter patients who may be appropriate candidates for opioid-free anesthesia. in another case in which opioid-free anesthesia was successfully provided, a female soldier on active duty underwent a cervical ganglionectomy 7 days after ultra-rapid opioid detoxification under general anesthesia.10 the patient was eager to return to duty and requested that opioid use be avoided. in that case, a balanced anesthetic including dexmedetomidine, ketamine, and a volatile anesthetic was used. in both that case and the present case, the patients wanted to prevent relapse by avoiding opioids during surgery. in both cases, the combination of an nmda receptor antagonist such as ketamine with an alpha-2 agonist, such as dexmedetomidine or clonidine, seemed to be especially effective for controlling hemodynamics intraoperatively and reducing postoperative pain. the benefits of opioid-free anesthesia are summarized in table 1. table 1. the benefits of opioid-free anesthesia • providing superior postoperative pain control by protecting the patient from surgical and opioid-induced hyperalgesia • minimizing respiratory depression in patients with impaired respiratory function, such as patients with chronic obstructive pulmonary disease, sleep apnea, and obesity • treating patients with chronic pain conditions, patients receiving chronic opioid therapy, patients with addiction, or patients in recovery and treatment for opioid use disorder (eg, with methadone or buprenorphine-naloxone) • minimizing postoperative cognitive dysfunction • minimizing other side effects of opioids such as nausea, pruritus, immune suppression, urinary retention, and constipation the growing opioid crisis has implications for practitioners in the fields of surgery and anesthesia. substance abuse should be addressed early and frankly by providers, and patients should be reassured that their pain can be effectively controlled and their risk for relapse minimized. opioid-free anesthesia should be considered as a means of achieving these goals. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 8 2018 page 40 references 1. ahrnsbrak r, bose j, hedden sl, lipari rn, park-lee e. key substance use and mental health indicators in the united states: results from the 2016 national survey on drug use and health. rockville, md: substance abuse and mental health services administration; 2017. https://www.samhsa.gov/data/sites/default/files/nsduh-ffr1-2016/nsduh-ffr1-2016.htm. accessed january 25, 2018. 2. hedegaard h, warner m, miniño am. drug overdose deaths in the united states, 1999–2016. nchs data brief. 2017;294. https://www.cdc.gov/nchs/data/databriefs/db294.pdf. accessed january 25, 2018. 3. chen ky, chen l, mao j. buprenorphine-naloxone therapy in pain management. anesthesiology. 2014;120(5):1262-1274. https://doi.org/10.1097/aln.0000000000000170. 4. anderson ta, quaye ana, ward en, wilens te, hilliard pe, brummett cm. to stop or not, that is the question: acute pain management for the patient on chronic buprenorphine. anesthesiology. 2017;126(6):1180-1186. https://doi.org/10.1097/ aln.0000000000001633. 5. may ja, white hc, leonard-white a, warltier dc, pagel ps. the patient recovering from alcohol or drug addiction: special issues for the anesthesiologist. anesth analg. 2001;92(6):1601-1608. https://doi.org/10.1097/00000539-200106000-00050. 6. vadivelu n, mitra s, kaye ad, urman rd. perioperative analgesia and challenges in the drug-addicted and drug-dependent patient. best pract res clin anaesthesiol. 2014;28(1):91-101. https://doi.org/10.1016/j.bpa.2014.02.003. 7. chou r, gordon db, de leon-casasola oa, et al. management of postoperative pain: a clinical practice guideline from the american pain society, the american society of regional anesthesia and pain medicine, and the american society of anesthesiologists’ committee on regional anesthesia, executive committee, and administrative council. j pain. 2016;17(2):131-157. https://doi.org/10.1016/j.jpain.2015.12.008. 8. chandrakantan a, glass ps. multimodal therapies for postoperative nausea and vomiting, and pain. br j anaesth. 2011;107(suppl 1):i27-i40. https://doi.org/10.1093/bja/aer358. 9. ziemann-gimmel p, goldfarb aa, koppman j, marema rt. opioid-free total intravenous anaesthesia reduces postoperative nausea and vomiting in bariatric surgery beyond triple prophylaxis. br j anaesth. 2014;112(5):906-911. https://doi. org/10.1093/bja/aet551. 10. plunkett a, fahlgren m, mclean b, mundey d. opioid-free balanced anesthesia for cervical ganglionectomy subsequent to recent ultra rapid opioid detoxification. pain med. 2009;10(4):767-770. https://doi.org/10.1111/j.1526-4637.2009.00610.x. anesthesia ejournal volume 3 issue 2 2015 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 ultrasound-guided regional anesthesia is now recognized as the evolving alternative to standard landmark-based techniques for nerve blockade and vascular access. the limitations of this technique begin to be recognized, however, as needle angles increase beyond 30 degrees, as commonly used for deep injections. this limitation remains difficult to overcome, especially for novice users. loss of needle visibility on the monitor screen remains a source of frustration for many providers, leaving them confused as to ultrasound’s true utility. this article explores a simple, reliable technique for improved needle visibility on any ultrasound machine through triangulation of 3 points using the law of sines. the three points of ultrasound triangulation are (1) the location of the ultrasound probe, (2) the nerve target, and (3) the site of needle entry. the location of the ultrasound probe is chosen by the user and the depth to the nerve is displayed by the ultrasound machine. the third point, the needle entry site, is based on the law of sines to ensure a needle entry angle of less than 30 degrees. this approach can simplify a challenging aspect of ultrasound-guided regional techniques. keywords: anesthesiology, increased needle visualization under ultrasound, law of sines, needle visualization, needle enhancement, ultrasonography abstract reliable needle visualization during ultrasound-guided regional procedures: a simple solution to steep-angle echogenicity loss based on target depth jonathan kline, crna, msna affiliation: director of education at twin oaks anesthesia services. contact twinoaksanesthesia@gmail.com funding/conflict of interest disclosure: none introduction ultrasound-guided regional anesthesia is now recognized as the evolving alternative to standard landmark-based techniques for nerve blockade and vascular access. since the first documented anesthesia application of ultrasound in 1978 by la grange,1 techniques have improved and clinical use has increased. ultrasound use has shown increased success, and to some extent increased safety, versus blind techniques.2 it seems logical that the ability to actually visualize the needle during regional anesthetic placement allows for greater safety and success, although current literature is slow to support the former. the limitations of ultrasound-guided regional anesthesia began to be recognized, however, as needle angles increase, as is common for deep injections. this limitation remains difficult to overcome, especially for novice users. loss of needle visibility on the monitor screen remains a source of irritation for many providers, leaving them confused as to ultrasound’s true utility. if the angle at which the ultrasound waves hit the needle shaft is from a relatively parallel origin, such as in shallow injection techniques, the needle can be displayed as a hyperechoic (bright white) line that is easy to visualize. as the angle departs from parallel and exceeds greater than about 30 degrees, the ultrasound wave fails to return to the probe. this reliably happens in all ultrasound systems regardless of make or manufacturer. this in essence describes the physics problem associated with visualization during steep needle angle paths. we sought a simple, easily incorporated and cost-effective solution to this problem. one method would be to add software to the system allowing the probe to adjust the beam angle to compensate for needle approaches greater than 30 degrees. another cheaper, more reliable, and less complex method would be to simply adjust the needle angle. because depth readings are a fairly standard display in the ultrasound industry, we decided to use this single variable to provide a map for allowing increased needle visualization based on this piece of readable information. review of the literature a current review of the literature was conducted by using the terms “increased needle visualization under ultrasound,” “law of sines,” “needle visualization,” and “needle enhancement.” the ultrasound system processor displays a needle by way of specular reflection. chan and perlas3 describe specular reflection as the processing of ultrasound wave return from an object that is long and smooth. the wave return to the probe for processing is in a single direction. the object must be in an orientation to the ultrasound beam that is relatively similar to the angle of origin. “there is increased signal wave return as the needle is more parallel to the ultrasound’s probe face”. this orientation ensures that the majority of the emitted waves are received and processed.4 specular reflection differs greatly from what is known as diffuse reflection. chan and perlas3 describe diffuse reflection as poor return of ultrasound waves from an object that is irregular in nature or has steep angles. steep needle angles encourage wave refraction, or diffusion of ultrasound waves away from the probe. because these waves fail to return to the probe, less information is available for processing, thus resulting in poor image resolution.4  there is a unique element in the processing of hollow needle ultrasound return waves. the beam strength exceeds the strength of the needle shaft on the away path but not on the return path to the probe. ultrasound waves become trapped within the lumen of the needle and return to the probe in a delayed fashion. the delay occurs because the waves easily penetrate the outer lumen of the needle on the away path but are reflected back to the lumen multiple times on the return path. this happens in a repeated fashion until the waves manage to penetrate the needle’s superficial wall and return to the probe. the bouncing around of these waves produces a delay in the return time. these wave bursts return in a staggered fashion, producing an image of a repeating needle on the screen. this was described by reusz et al4 as an artifact occurring at increasing depths until the needle angle changes or the wave strength is decreased. this is known as reverberation artifact.5 as early as 2004, needle visualization loss was reported. schafhalter-zoppoth and colleagues5 noted that, as the needle angle increased (or became steeper), needle visibility decreased. this was a reproducible finding in human tissue, but those authors did not use a variety of ultrasound equipment. miura et al6 also described needle visualization loss at particular angles. an important element from this article was the clear loss of visualization with a linear probe at between 30 and 45 degrees.6 this article was probably the first report making the link between linear probe use and steep needle angle visualization loss. this is important to clinical practice because most scans and needle techniques commonly used in anesthesia care are performed with a linear probe. the characteristic of increased insertion and visualization loss is not unique to needle insertion. junji et al7 observed that peri-neural catheters also exhibit similar visual loss during ultrasound techniques when placed at steeper angles. interestingly, the visual loss is less pronounced with a curvilinear probe at steeper angles. similar results were reported by abbal and colleagues.8 hocking et al9 observed that the use of cadaveric tissue versus commercially available alternatives to assess needle visibility differed in echogenicity. he noted that phantoms and gel mediums had a low background echogenicity and would therefore exaggerate needle visibility during skills acquisition. this differed from fresh-frozen cadavers in that they retained greater lifelike clinical echogenicity. this is important when evaluating needle angle visual loss, because the medium in which the evaluation occurs influences needle visibility.9 in essence, this means that techniques are easier to perform on simulators and gel mediums than on actual human tissue. it has yet to be evaluated whether ultrasound-guided skills acquisition is made more efficient by the addition of formal training on simulators prior to actual patient care, although this seems to make sense. hebard and colleagues10 quantifiably linked steep needle angles to visual loss. in this important article, they also concluded that every 10-degree increase in needle angle steepness resulted in a 12% visual loss. stated another way, if the needle angle exceeds about 40 degrees, visualization of that needle decreases by about half. weismann et al11 confirmed earlier findings that correlated visual loss with steep angle insertion. those authors also observed that this visual loss was less severe if the needle was visualized by use of ultrasound beam compound imaging.11 this literature review points to a few interesting correlations. if needle angles exceed about 30 to 40 degrees, visualization ultimately decreases. the only way described in the current literature to alleviate this problem is to use some sort of ultrasound beam alteration or enhancement, or to change to a curved probe (which is usually unsuitable for most anesthesiarelated procedures). description of technique for improved needle visibility we developed a method whereby a clinician can place an inplane needle under any ultrasound beam and be able to visualize it, regardless of depth of the target, age, or complexity of the machine. this method can allow even the most inexperienced providers access to readily viewable needles on the monitor during regional and vascular procedures. the criteria for this new method are as follows: 1) the needle angle cannot exceed 30 degrees. 2) the needle guidance software and enhancement cannot be engaged, as there are too many variables to consider regarding current and older systems. 3) only standard block needles, which are easy to obtain and cost-effective, should be used.  we first determined the pieces of information easily accessible by virtually all ultrasound machines. the commonality was depth. reading the depth on the screen was nearly universal among the surveyed machines in current practice. the second piece of information known from the literature review was that 30 degrees seemed to be the maximum allowable angle to produce perfectly readable needle echogenicity. this cutoff applies to needles placed in-plane. although a great many other pieces of information were available, they were not common to virtually all machines. thus, on the basis of these pieces of information, we sought to complete anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 a simple method to allow anyone to produce readable needles at any depth.  the solution was described as a simple inverted triangle (figure 1). the base of the triangle became the probe interface with the skin. the height of the triangle became the depth to the target of interest. this left only the distance from the probe to begin needle entry, keeping in mind that the needle could not exceed 30 degrees of approach to the target.  figure 1. triangulation of 3 points using the law of sines: (1) the location of the ultrasound probe, (2) the nerve target, and (3) the site of needle entry. figure 2 shows images revealing the difficulty of needle visualization during steeper needle angles. note that in image a, the needle shows up displaying strong echogenicity. this is an excellent example of an entry that is less than 30 degrees. image b shows the same needle on the same patient, but visualization of that needle is markedly decreased. image b shows the visual loss as reduced echogenicity of the needle shaft at a larger insertion angle. figure 1 needle visualization applying the law of sines a b c probe center 1 cm 2 cm 3 cm ? point of needle entry 30 degrees a/a sin= b/b sin= c/c sin target jonathan p. kline, crna in solving this triangle problem, we used the law of sines. although there are many variations of this solution, we used a simple technique that allowed for a simple formula to be used based solely on the depth of the target structure. for example, if the target structure is 4 cm in depth and the approach cannot exceed 30 degrees without signal loss (leading to decreased needle visualization), the skin must be entered at exactly 6.92 cm from the probe. this solution is reliable and reproducible every time. it allows for a simple formula to be incorporated to ensure successful needle visualization, regardless of the age or complexity of the ultrasound machine. it is important to note that the center of the probe (not the edge) is the beginning point for the triangle’s base measurement. table 1 presents common needle angle distances developed on the basis of the law of sines.  the new total distance to the target that the needle will have to travel is also included. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 image b figure 2. images a and b are actual patient (in vivo) pictures captured during an ultrasound-guided regional procedure. (images from jonathan kline, crna.) image a references 1. la grange pdp, foster pa, pretorius lk. application of the doppler ultrasound blood flow detector in supraclavicular brachial plexus block. br j anaesth. 1978;50(9):965-967. http://dx.doi.org/10.1093/bja/50.9.965. 2. marhofer p, greher m, kapral s. ultrasound guidance in regional anaesthesia. br j anaesth. 2005;94(1):7–17. doi: http://dx.doi. org/10.1093/bja/aei002. published online july 26, 2004. 3. chan v, perlas a. atlas of ultrasound-guided procedures in interventional pain management. in: chan v, perlas a. basics of ultrasound imaging. new york: springer science business media; 2011:13-19. doi: http://dx.doi.org/10.1007/978-1-44191681-5_2. 4. reusz g, sarkany j, gal j, csomos a. needle-related ultrasound artifacts and their importance in anaesthetic practice. br j anaesth. 2014;112(5):794-802. http://dx.doi.org/10.1093/bja/aet585. 5. schafhalter-zoppoth i, mcculloch ce, gray at. ultrasound visibility of needles used for regional nerve block: an in vitro study. reg anesth pain med. 2004;29(5):480-488. http://dx.doi.org/10.1097/00115550-200409000-00014. 6. miura m, kazuhide t, toshiyasu s. visibility of ultrasound-guided echogenic needle and its potential in clinical delivery of regional anesthesia. tokai j exp clin med. 2014;39(2):80-86. 7. takatani j, takeshima n, okuda k, uchino t, noguchi t. ultrasound visibility of regional anesthesia catheters: an in vitro study. korean j anesthesiol. 2012;63(1):59-64. http://dx.doi.org/10.4097/kjae.2012.63.1.59. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 table 1. application chart of the law of sines for increased needle visibility during ultrasound-guided regional procedures discussion the benefits of incorporating this chart into clinical use are straightforward. allowing users to see needles, even during deep structure targeting, may allow for increased safety and effectiveness for every technique. the formula is simple to incorporate and requires only one piece of information to use. this piece of information is the depth of the target structure. the depth is available on most clinical ultrasounds in use today. as an added, albeit unforeseen benefit of this discovery, the chart also reveals not only the point of entry that will enhance needle visibility but also the total distance the needle will be required to travel. this will simplify needle length selection before the start of a procedure.  some problems may be associated with this technique. this chart or technique is difficult to use if the probe is placed in a position that may be difficult to measure accurately. also, the region must be relatively flat in order to ensure relative accuracy of the formula. the technique described to increase visualization dictates the distance that the needle must be placed from the probe. as the target depth increases (albeit beyond most common clinical depths), such as beyond 6.5 cm, needles greater than 10 cm must be used. this may represent a special order item and may therefore increase cost or exclude use of the technique by centers that lack the necessary needle length. increased needle distances may become uncomfortable for the patient, because it will become difficult to localize an area at great depth from the projected needle insertion site. it is difficult to assess or predict patient comfort in this arena, but an adequate volume of a fast-acting, dilute local anesthetic to the projected needle path may prove more comfortable for patients having deep injections. another obvious deficit in this chart is the lack of necessary information regarding targets greater than 10 cm. however, it would be rare for a patient to require an injection or vessel access at this depth without another more feasible alternative. we recommend a formulated study to formalize these theoretical suggestions. conclusion ultrasound guidance has promoted increased effectiveness, and to some degree safety, during regional anesthesia techniques and vascular access.12 we sought to produce and describe a technique that would simplify anesthesia providers’ attempts to visualize needles during any regional or vascular procedure. we determined that by use of the law of sines, a simple distance could reliably be used to increase needle visualization during ultrasound-guided regional procedures. to use this chart, one only needs to know the target depth, and this seems to be available on most clinically used ultrasound systems. as shown in the table, many clinically relevant depths to target structures (ranging from 2 to 10 cm) can be used with reliable results. these results lead to increased needle visualization with the most primitive to the most complex ultrasound systems.  acknowledgments special thanks to bill gordan, crna, for his assistance with this article. anesthesia ejournal volume 2 issue 2 2014 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 background: achieving adequate anesthetic depth during an ect procedure without suppressing the therapeutic seizure is challenging and increases the risk of patient awareness during the procedure. aim: to assess provider satisfaction with, and identify potential barriers to the use of bis monitoring during ect as a means to determine the feasibility of adopting bis monitoring in the clinical ect setting. setting: the pilot project was conducted in a 274-bed general medical and tertiary care facility located on the mid-atlantic coast that provides services to more than 200,000 patients and administers over 200 ect treatments annually. participants: psychiatry staff and nurse anesthetists caring for patients undergoing ect. methods: a convenience sample of 11 patients scheduled for 25 ect treatments received bis monitoring. provider (n= 12) satisfaction was anonymously assessed using an 8-question survey. results: while 7 of the 12 providers rated their overall satisfaction with using the bis monitor during ect as very good only 2 providers affirmatively answered the bis monitor added value to their decision-making process. two anesthetized patients, who responded purposefully to verbal commands despite bis values in the deep hypnotic range indicating sufficient anesthetic depth, were considered at risk for awareness under anesthesia. conclusions: provider acceptance of the introduction of bis monitoring to assess anesthetic depth during ect was lukewarm at best. while the concept appears sound, one must question if the technology and tools are sufficiently developed to warrant its routine use in the described setting. given the response of the two patients with bis values indicating sufficient anesthetic depth, these observations merit further studies to replicate our findings in the psychiatric population and further explore the potential value of bis monitoring during ect. key words: electroconvulsive therapy; ect; consciousness monitors; bispectral index monitor; intraoperative awareness; anesthesia awareness; awareness during anesthesia abstract improving anesthetic depth assessment during electroconvulsive therapy with bispectral index monitoring: a pilot quality improvement project j. frank titch, dnp, crna tracey holsinger, md charles vacchiano, phd, crna jane blood-siegfried, dnsc, cpnp affiliation: from the department of psychiatry, durham va medical center, durham, nc and the duke university school of nursing, durham, nc. author correspondence: j. frank titch, dnp, crna, duke university school of nursing, dumc 3322, 307 trent dr., durham, nc 27710 (frank.titch@duke.edu); 919.684.5772 funding disclosure: departmental and institutional resources provided the principle financial support for this project. none of the authors have a conflict of interest to report. mailto:frank.titch@duke.edu anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 2 2014 introduction background knowledge electroconvulsive therapy (ect), a recognized treatment for certain neuropsychiatric disorders, is performed after the administration of a short-acting intravenous hypnotic followed by the administration of a short-acting muscle paralytic that attenuates motor seizure activity.1 the intravenous anesthetic depresses therapeutic seizure activity in a dose-dependent manner.2 given the challenge of achieving adequate anesthetic depth without suppressing the therapeutic seizure, the patient is at increased risk for awareness while paralyzed before the electrical stimulus.3 a search of the literature identified 3 case reports of awareness and recall during ect therapy.4-6 problem multiple sources cite light anesthesia, or an imbalance between anesthesia delivery and need, as the most common cause of awareness under anesthesia.7-9 reported long-term psychological sequelae after awareness under anesthesia include anxiety, depression, nightmares, post-traumatic stress disorder (ptsd), and flashbacks.10,11 previous studies have shown the bispectral index (bis) monitor to be a reliable anesthesia depth monitor that lowers the incidence of awareness.12 the device is an electroencephalogram-derived monitor that provides real-time, continuous measurement of hypnosis, optimizing anesthetic drug delivery and avoiding extremes of drug dosages.13,14 however, use of bis monitoring to prevent awareness under anesthesia during ect, the actual incidence of awareness during ect, and the process of implementing bis monitoring in the clinical setting during ect are not well reported in the psychiatric literature. intended improvement current practice standards do not require bis monitoring during ect; therefore, we designed this pilot project to assess the feasibility of using the bis during ect in an active day-to-day clinical setting and evaluate its impact on provider satisfaction. specifically, we report on the practical feasibility of developing full-scale implementation, pilot findings related to provider satisfaction, and potential barriers that may influence its use. prospective barriers to the implementation of standardized bis monitoring for ect may be associated with many factors, such as the integrity of bis values, provider satisfaction, increased treatment times, and cost of supplies. consequently, the purpose of this pilot project was to implement a practice change using the bis monitor to assess anesthetic depth during ect to improve quality and safety and evaluate its effectiveness. the goal of bis is to minimize the risk of awareness with recall that may lead to ptsd in this psychologically vulnerable population. in particular, we wanted to determine whether it was feasible to use the bis during ect and whether anesthesia providers would find it useful in day-to-day practice. to most accurately replicate implementation of such a change into an active practice, we chose a pilot project, selected a convenience sample, and did not standardize the anesthetic protocol. we report the complexities associated with implementing such a protocol during the administration of ect. methods ethical concerns the facility’s institutional review board approved both the pilot project’s implementation and subsequent survey analysis. both the chair of the psychiatry department and the attending psychiatrist provided organizational consent. we reported only de-identified data. setting the project was conducted in a 274-bed general medical and tertiary care facility on the mid-atlantic coast that provides services to more than 200,000 patients living in a 26-county area. the facility treats more than 46,000 patients who make more than 339,000 outpatient visits annually. psychiatric care is provided in both inpatient and outpatient settings and, at the time of the project, the psychiatry service administered slightly more than 200 ect treatments yearly. intervention we undertook a pilot project to assess the feasibility of using bis monitoring during ect. a convenience sample of 11 patients scheduled for 25 ect treatments as a routine healthcare service event received bis monitoring over 53 calendar days. patients were not randomly assigned to a study arm, and all patients received bilateral temporal index or maintenance ect treatments using the spectrum 5000q® (mecta corp., lake oswego, or). standard procedural monitors, including a noninvasive blood pressure cuff, 5-lead electrocardiogram, pulse oximetry, and capnography, were employed during the ect procedure. per the manufacturer’s protocol, the bis monitor was applied to the patient’s forehead when the patient entered the treatment area, and the device recorded values throughout the procedure. the bis electroencephalogram signal was acquired using a 4-electrode disposable sensor (bistm quatro sensor; covidien, boulder, co) applied to the patient’s forehead as recommended by the manufacturer. the signal was then analyzed and recorded using the bis vistatm monitoring system (software revision 1.13.2.5; covidien) with the latency period set at 15 seconds. on connecting the sensor to the monitoring system, the manufacturer’s proprietary sensory integrity check software tests the impedance of each electrode and does not begin normal processing of the bis value until the impedance test is successfully completed. we did not standardize anesthetic techniques for this pilot project. during the preoxygenation period, patients may or may not have received intravenous caffeine, labetalol, or opioid medications. general anesthesia was induced intravenously with either methohexital or etomidate after the administration of 100% oxygen by mask. on loss of responsiveness to verbal commands and eyelash reflex, we inflated a blood pressure cuff on the right lower leg, isolating circulation to the foot before succinylcholine administration. after the induction of hypnosis and paralysis, patients were asked to move the toes of their right foot. if there was no response, bis values were noted and an electrical stimulus was delivered via bitemporal electrodes. we determined response to verbal command and motor seizure duration using the unparalyzed isolated right foot, while the duration of the induced seizure was recorded using single bifrontal electroencephalogram leads monitored through the spectrum 5000q. we provided controlled ventilation throughout the procedure with 100% oxygen until the resumption of spontaneous breathing. we removed all monitors, and patients were transported to the postanesthesia care unit for additional monitoring. evaluation following the sampled 25 ect treatments, we anonymously assessed provider satisfaction with use of the bis monitor during ect using an 8-question, check-box paper survey. participating psychiatry and nurse anesthesia providers (n=12) received the survey in an opaque envelope with instructions for completion. we developed the survey instrument using questions from previous surveys provided by the bis manufacturer, and the survey’s content validity was peer-reviewed by 5 nurse anesthetists and 1 research nurse not linked with the project. in addition, we tracked procedure times for each treatment. analysis we performed statistical analyses using the spss statistics software for windows (version 19; ibm inc., somers, ny) and descriptive statistics to synthesize and describe the survey analysis. we analyzed survey responses by question type and evaluated the provider’s comfort level using the bis monitor, satisfaction using it for ect, and the added value of using bis monitoring in the ect setting. to assess provider comfort and satisfaction, we used a 5-point likert scale with the response alternatives of poor, below average, average, very good, or excellent. responses of very good or excellent were considered affirmative answers, and a response of average was considered neutral. we assessed the added value of bis monitoring during ect using a 5-point likert scale of never, rarely, occasionally, frequently, and always, with frequently and always considered affirmative answers and occasionally considered a neutral answer. results outcomes after 25 ect treatments for 11 patients, all providers (n=12) directly involved with patient care during the pilot project completed the survey. all respondents denied having previously used the bis monitor during ect. however, 10 respondents reported routinely using the bis to monitor depth of anesthesia during general anesthesia. eleven providers reported personally using bis technology for more than 3 years in the surgical setting; 9 of those respondents reported more than 5 years of experience. three rated their level of comfort with using the bis as very good, while 6 rated their comfort level as excellent. eleven providers rated their overall satisfaction with using the bis monitor during ect as average (4) or very good (7). no one rated his or her satisfaction as excellent. ten providers responded that the bis monitor added value to their decisionmaking process either occasionally (8) or frequently (2) during ect. no respondents said they felt the bis monitor always added value during ect. procedure time of the 25 procedures tracked, the mean procedure time was 26±6 minutes, ranging from 15 minutes to 39 minutes. numerous factors such as difficult intravenous access, individual provider, or total number of supporting psychiatry nurses confounded accounting for any additional procedure time resulting from inclusion of the bis monitor during ect. discussion summary although most providers were comfortable using bis technology, the survey results from this pilot project demonstrate that the overall reaction to assessing anesthetic depth with the bis monitor during ect was lukewarm at best. while 7 of the 12 providers rated their overall satisfaction with using the bis monitor during ect as very good, only 2 providers reported that the bis monitor added value to their decision-making process. much to our surprise, we also discovered that the bis monitor alone did not allow consistent and accurate assessment of the patient’s anesthetic depth before delivery of the electrical stimulus. two anesthetized patients who responded purposefully to verbal commands despite bis values in the deep hypnotic range (40-60), indicating sufficient anesthetic depth, were considered at risk for awareness under anesthesia and received additional intravenous anesthetic (table 1). however, no patients reported postseizure recall of events regardless of the prestimulus bis score. table 1 – pre-stimulus purposeful responses to verbal commands interpretations initially, we were unsure how to integrate the bis into everyday practice and did not wish to spend excessive time incorporating the device, which affected our ability to acquire a good signal quality in all cases. we were attempting to replicate true clinical practice and determine if the device would be useful. due to limited available forehead space in patients receiving bilateral temporal ect, the sensor was difficult to properly place. the monitor would not begin normal processing of the bis value until it successfully completed its impedance test; therefore, it failed to record any data during 2 treatments. in addition, we were unable to record baseline bis values, considered critical before the administration of anesthesia, for 6 of the 25 treatments. the device, in our view, required too much effort to troubleshoot, and we did not wish to excessively prolong the procedure. however, we began prewarming the bis sensor array and applied a very small amount of ect electrode gel to each 4-electrode disposable bis sensor before patient application. following initiation of this change at treatment 11, we consistently gathered bis data for the duration of the project. anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 2 2014 treatment pre-stimulus bis emg sqi 4 42 48 90 10 40 29 98 note. emg=electromyography; sqi=signal quality index anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 2 2014 limitations while the results of our pilot project are important, they must be viewed through the lens of their limitations. the financial implications must be considered and include extended procedure times and the equipment expense. unfortunately, too many additional variables confounded our ability to accurately assess any extension of procedure times. for the purposes of this project, bis monitoring devices were readily available in the facility, but this may not always be the case and may represent an additional expense. each bistm quatro sensor cost our institution $25.20, resulting in an additional $630 for the 18 (72%) treatments supplying usable data. in addition, spiegel and colleagues (2006) have proposed that the bis could prove useful in the early diagnosis of certain neurological diseases such as alzheimer’s.15 such findings suggest that bis values are altered in patients with certain psychiatric conditions and the threshold indicating hypnosis in patients requiring ect may differ from that of the rest of the population. conclusions the ect setting would appear to offer an ideal application for the introduction of bis monitoring. yet, except for reports of using bis monitoring for targeted anesthetic dosage administration, reports of its use in the psychiatric literature during ect are limited.13,16,17 achieving adequate anesthetic depth during the ect procedure without suppressing the therapeutic seizure is challenging and increases the risk of patient awareness.3 indeed, case reports describing instances of patient awareness during ect exist in the literature.4-6 past studies have also shown that using the bis monitor reduces the incidence of awareness under anesthesia in at-risk patients.18,19 while the concept appears sound in its foundation, one must question if the technology and tools are sufficiently developed to warrant its routine use in the ect setting. based on our experiences, we would not recommend implementation. could exclusive reliance on the device mask an insufficiently anesthetized patient? given the intra-anesthetic purposeful response of two patients despite bis values in the deep hypnotic range (40-60), indicating sufficient anesthetic depth, further studies are needed to replicate our findings in the psychiatric population and explore the potential value of bis monitoring during ect. references 1. hooten wm, rasmussen kg jr. effects of general anesthetic agents in adults receiving electroconvulsive therapy: a systematic review. j ect. 2008;24(3):208–223. doi:10.1097/yct.0b013e31815bfe2a. 2. sartorius a, muñoz-canales e, krumm b, et al. ect anesthesia: the lighter the better? pharmacopsychiatry. 2006;39(6):201– 204. doi:10.1055/s-2006-950395. 3. deiner s, frost ea. electroconvulsive therapy and anesthesia. int anesthesiol clin. 2009;47(2):81–92. doi:10.1097/ aia.0b013e3181939b37. 4 . andrade c, thirthalli j, gangadhar bn. unilateral nondominant electrode placement as a risk factor for recall of awareness under anesthesia during electroconvulsive therapy. j ect. 2007;23(3):201–203. doi:10.1097/yct.0b013e3180cab6a4. 5. gajwani p, muzina d, gao k, calabrese jr. awareness under anesthesia during electroconvulsive therapy treatment. j ect. 2006;22(2):158–159. 6. litt l, li d. awareness without recall during anesthesia for electroconvulsive therapy. anesthesiology. 2007;106(4):871–872. doi:10.1097/01.anes.0000264771.64168.63. 7. ghoneim mm. awareness during anesthesia. anesthesiology. 2000;92(2):597–602. 8. myles ps, leslie k, mcneil j, forbes a, chan mt. bispectral index monitoring to prevent awareness during anaesthesia: the b-aware randomised controlled trial. lancet. 2004;363(9423):1757–1763. doi:10.1016/s0140-6736(04)16300-9. 9. pollard rj, coyle jp, gilbert rl, beck je. intraoperative awareness in a regional medical system: a review of 3 years’ data. anesthesiology. 2007;106(2):269–274. 10. leslie k, chan mt, myles ps, forbes a, mcculloch tj. posttraumatic stress disorder in aware patients from the b-aware trial. anesth analg. 2010;110(3):823–828. doi:10.1213/ane.0b013e3181b8b6ca. 11. samuelsson p, brudin l, sandin rh. late psychological symptoms after awareness among consecutively included surgical patients. anesthesiology. 2007;106(1):26–32. 12. kotsovolis g, komninos g. awareness during anesthesia: how sure can we be that the patient is sleeping indeed? hippokratia. 2009;13(2):83–89. 13. hanss r, bauer m, bein b, et al. bispectral index-controlled anaesthesia for electroconvulsive therapy. eur j anaesthesiol. 2006;23(3):202–207. doi:10.1017/s026502150500219x. 14. johansen jw. update on bispectral index monitoring. best pract res clin anaesthesiol. 2006;20(1):81–99. doi:10.1016/j. bpa.2005.08.004. 15. spiegel a, tonner ph, renna m. altered states of consciousness: processed eeg in mental disease. best pract research clin anaesthesiol. 2006;20(1):57–67. 16. soehle m, kayser s, ellerkmann rk, schlaepfer te. bilateral bispectral index monitoring during and after electroconvulsive therapy compared with magnetic seizure therapy for treatment-resistant depression. br j anaesth. 2014;112(4):695–702. doi:10.1093/bja/aet410. 17. sartorius a, krier a, andres fj, bender hj, krumm b, henn fa. bispectral index monitoring for more effective electroconvulsive therapy? br j anaesth. 2006;96(6):806–807. doi:10.1093/bja/ael091. 18. leslie k, myles ps, forbes a, chan mt, short tg, swallow sk. recovery from bispectral index-guided anaesthesia in a large randomized controlled trial of patients at high risk of awareness. anaesth intensive care. 2005;33(4):443–451. 19. punjasawadwong y, phongchiewboon a, bunchungmongkol n. bispectral index for improving anaesthetic delivery and postoperative recovery. cochrane database syst rev. 2014 jun 17;6:cd003843. doi: 10.1002/14651858.cd003843.pub3. anesthesia ejournal www.anesthesiaejournal.com volume 2 issue 2 2014 anesthesia ejournal volume 4 issue 1 2016 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 page 20 anesthetic management of a patient with mitochondrial encephalopathy, lactic acidosis, and stroke-like symptoms (melas): a case study annabelle flanagan dnp, crna affiliation: texas christian university, email: annabelle.h.flanagan@gmail.com dennis cheek phd, rn affiliation: texas christian university, email: d.cheek@tcu.edu funding/conflict of interest disclosure: none keywords: melas, mitochondrial disorders, anesthetic management, mitochondrial myopathy introduction mitochondrial myopathies (mms) represent a wide range of defects in the mitochondria.1 mitochondrial encephalopathy, lactic acidosis, and stroke-like symptoms (melas) syndrome is a type of mitochondrial disease that is systemic in nature.2 this is because of the multiple functions mitochondria serve in oxidative phosphorylation. melas has been speculated to affect respiratory enzyme complexes i and iv, which are essential in converting substrates from glycolysis, fatty acid oxidation, and the tricarboxylic acid cycle to atp.1,3 this disease is thought to pass maternally and to result from a mutation in mitochondrial dna.1,2 because melas involves a mitochondrial defect in aerobic metabolism, the disease has implications for anesthesia management. anesthetic medications, surgery itself, and fasting in preparation for surgery can all increase the metabolic burden, leading to possible exacerbations in tissues dependent on large amounts of oxygen, such as the heart, muscle, and central nervous system.4,5 mms have also been speculatively linked to malignant hyperthermia owing to the similar presentation of symptoms. controversy exists, however, over whether anesthetic management should be based on concerns to avoid malignant hyperthermia triggers. abstract mitochondrial encephalopathy, lactic acidosis, stroke-like symptoms (melas) syndrome is a specific mitochondrial myopathy that results in defects in respiratory enzyme complexes i and iv. this ultimately causes defects in aerobic metabolism, especially in high-energy-requiring organs, leading to an obvious concern with anesthetic management. some mitochondrial myopathies have speculative linkages to malignant hyperthermia. this case report examines the anesthetic implications for a patient with melas. a 39-year-old man with melas underwent a right hip fracture pinning. the patient was successfully managed with a general endotracheal anesthetic using a propofol infusion and <1 minimum alveolar concentration of sevoflurane gas. the patient was extubated without complications. anesthetic implications for the management of patients with melas include a tailored preoperative assessment because of the different phenotypical presentations of mitochondrial diseases. the metabolic burden in melas patients can be reduced by avoidance of the following: lactate in intravenous fluids, hypothermia, prolonged fasting, and postoperative nausea vomiting. varied anesthetic techniques have been documented in multiple case reports. careful titration of muscle relaxants and opioids is paramount to prevent postoperative respiratory failure. according to the malignant hyperthermia association of the united states, avoidance of volatile anesthetics is not necessary in patients with mitochondrial myopathy. mailto:annabelle.h.flanagan@gmail.com mailto:d.cheek@tcu.edu anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 21 case summary a 39-year-old hispanic male, with a weight of 49 kg and a height of 157 cm, presented with a right hip fracture. the surgical procedure planned for this patient was a right hip fracture pinning. his previous medical history included a cerebrovascular accident in 2008 apparently while operating a motor vehicle. immediately before this motor vehicle accident, the patient had blurry vision and a subsequent seizure. upon admission to the hospital after the motor vehicle accident, a muscle biopsy was performed and the myopathy melas was discovered. the patient’s other medical conditions included hearing loss, diabetes, and an unsteady gait related to the motor vehicle accident. the patient’s medications included aspirin, insulin, pantoprazole, carbamazepine, zonisamide, co-enzyme q10, iron, loratadine, and morphine. he was assessed as having an airway classification of mallampati ii, with a 4-fingerbreadth oral excursion and thyromental distance, normal upper and lower dentition, and normal neck extension and flexion. he had no known allergies to food or drugs. a review of his symptoms was essentially negative. the results of his physical exam were unremarkable other than a foley catheter that was in place and musculoskeletal decompensation from a worsening gait with no assistive device use. a 22-guage intravenous catheter was started in the right antecubital vein with an infusion of lactated ringer’s solution. the serum complete blood count showed a slightly elevated white blood cell count of 9.2 and a hemoglobin level of 11.9 g/dl. however, the results of the basic metabolic panel and coagulation studies were all within normal limits. his preoperative vital signs included blood pressure of 121/77 mm hg, heart rate of 90 beats per minute, normal sinus rhythm, respiratory rate of 16 breaths per minute, and skin temperature of 37.2 degrees celsius. his american society of anesthesiologists classification was designated as a iii. the anesthetic plan for this patient included administration of preoperative medications of midazolam 4 mg and ondansetron 4 mg for anxiolysis and prevention of postoperative nausea and vomiting. general endotracheal anesthesia was instituted by use of a conventional macintosh laryngoscope blade (welch allyn, skaneateles falls, ny), the muscle relaxant cisatracurium 20 mg, and the induction agents of propofol 50 mg, lidocaine 1% 60 mg, and sufentanil 15 mcg. after securement of the airway, another large-bore intravenous catheter and an arterial catheter were started before the start of the case. maintenance anesthesia was continued with a propofol infusion set initially to 50 mcg/ kg/min, sevoflurane at a goal end tidal concentration of 1.5, <1 minimum alveolar concentration (mac), and boluses of 10 mcg of sufentanil as needed. the patient was to be woken up fully on emergence with evidence of eye opening, spontaneous ventilation, and sustained head lift to ensure adequate return of respiratory drive prior to extubation. upon arrival in the operating room, the patient was preoxygenated with 100% oxygen for 2 minutes with 10 l oxygen through a mask. pre-induction vital signs were heart rate of 92 beats per minute, normal sinus rhythm, skin temperature of 36 degrees celsius, noninvasive blood pressure of 111/82 mm hg, and spo2 of 100% as measured by pulse oximetry. intravenous induction medications included those mentioned previously in the anesthetic plan. induction was initiated with a conventional macintosh 3 laryngoscope blade. upon visualization of the airway, a cormack-lehane grade 4 was assessed. a gum elastic bougie tube introducer was passed with successful placement of a size 7.5-mm endotracheal tube. confirmation of adequate placement was by auscultation of equal bilateral breath sounds, bilateral chest rise, and positive end tidal carbon dioxide at 39 mm hg. sevoflurane gas was turned on to 1.5% with an end tidal concentration of 1.0 with 2 l of oxygen. the patient was placed on volume control mode on the mechanical ventilator with a tidal volume of 400 ml, rate of 10 breaths per minute, and positive inspiratory pressure of 14 mm hg. immediately after, another 18-gauge peripheral intravenous catheter in the left arm and a 20-gauge right radial catheter were started, 1 g of cefazolin was administered intravenously, and a propofol infusion was started. a forced air warmer and an intravenous fluid warmer were used to maintain patient normothermia. the intraoperative course remained uneventful. sufentanil boluses of 10 and 15 mcg were given for pain control as well as 100-mcg boluses of neo-synephrine (phenylephrine) to help maintain systolic blood pressure > 90 mm hg. no additional muscle relaxant was given. acetaminophen 1 g was also administered intravenously before the end of the case. the total crystalloid for the procedure was 1200 ml of lactated ringer’s solution. foley catheter output was 300 ml of dark amber urine. estimated blood loss was minimal at 50 ml. upon emergence, the patient was extubated awake, was spontaneously ventilating for 30 minutes with no pressure support, with eye opening, and with sustained head lift to 10 l of oxygen via a non-rebreather face mask at an end tidal sevoflurane concentration of 0.3. discussion mms were first discovered 56 years ago in a patient who had large amounts of mitochondria in skeletal muscle.3 these diseases cause a wide range of clinical problems, including leber’s hereditary optic neuropathy, chronic progressive ophthalmoplegia, kearns-sayre syndrome, myoclonic epilepsy and ragged-red fiber disease, and melas.3 the anesthetic management of patients with mms such as melas is complicated for many reasons involving genetic inheritance and mutation as well as the varying phenotypic presentations of these diseases. the same genetic mutation in mitochondrial dna may have different phenotypes in different patients, while different genetic mutations can also cause overlapping phenotypes.3 thus, the safe use of an anesthetic technique in a patient with one mitochondrial defect may not translate to equal safety across other mitochondrial diseases with identical mutations.5 one of the genetic mutations that has been attributed to melas has been identified as mttl1*melas3243g in the trnaleu that affects complex i of the respiratory enzyme complexes involved in oxidative phosphorylation.3 this mutation in mitochondrial dna when present in a high percentage is associated with stroke-like activity but when present in a low percentage is associated with diabetes and deafness.3 the patient in the present case report interestingly had strokelike activity, deafness, and diabetes. another source identifies the affected respiratory complex as complex iv; other sources identify multiple mitochondrial dna gene (trna and mrna) mutations and deletions responsible for melas.1,4,6 the patient in the present case did not have a genetic report and the inability to obtain muscle biopsy records from his previous hospital admission made it difficult to determine the exact inheritance method and specific clinical presentation. sources do, however, identify melas inheritance as being maternal in nature.2 diagnosis of melas must be individualized.6 most mms follow a slow and progressive course; thus, clinical investigations must be integrated by the same practitioner.4 integrative diagnosis includes clinical, electrophysiological, imaging, biochemical, and genetic investigations.5 genetic studies should be the first-line method for diagnosis after clinical features such as diabetes, deafness, and cardiomyopathy together raise red flags.6 after genetic studies, blood, urine, and cerebrospinal fluid studies should be conducted. if the results of these are negative, electrophysiological and neuroimaging studies should be performed in organs other than the nervous system.6 last, a muscle biopsy and biochemical investigations should be conducted for diagnosis if the results of all other testing are negative. these investigations can include electron microscopy and respiratory chain enzyme analysis of the muscle.6,7 there is no known cure for melas. one study showed marked improvement in stroke-like symptoms after administration of l-arginine, and more recently, exercise programs have been shown to prevent muscle deconditioning.7 other treatments include nutritional support with vitamins and cofactors; emotional therapy; physiologic stress reduction, such as environmental temperature control; and reducing toxin exposure, such as smoking.8 the clinical presentation of melas varies tremendously, and its incidence is rare: 12.5 cases per 100,000.2 most importantly for anesthesia management, the respiratory chain is the final common pathway essential for aerobic metabolism. patients present with symptoms that are dependent on tissues requiring large amounts of oxygen, such as the heart, central nervous system, and muscle.1 according to the online mendelian inheritance in man database, the general manifestations of melas range from “seizures, hemiparesis, hemianopsia, cortical blindness, to episodic vomiting.”9 specific central nervous system manifestations of melas can also include psychiatric abnormalities, neuropsychological deficits, stroke-like episodes, migraines, epilepsy, ataxia, and hypopituitarism.4 mms can affect a single organ system or multiple organ systems as in melas. other organ system manifestations in melas can include cardiomyopathies, wolff-parkinson-white syndrome, cardiac conduction pathway blockade, diabetes mellitus, sensorineural hearing loss, gastrointestinal dysfunction, malnutrition, and muscle wasting.2 preoperative evaluation of these patients must include tests specific to each organ system involved. cardiomyopathy is most commonly present in melas; thus, a 12-lead electrocardiogram and echocardiogram are paramount. 7 the patient in this case report denied any cardiac history and thus this was not obtained in the preoperative evaluation but may have been helpful in developing an appropriate anesthetic plan. other preoperative evaluation should include renal, hepatic, and blood glucose tests.10 a full neurologic evaluation should be conducted because melas patients can have stroke-like episodes mostly affecting the occipital and parietal lobes.4 exercise tolerance, swallowing, and respiratory functions are other considerations preoperatively, which may include chest x-ray imaging and pulmonary function tests.10 as a result of the inability of pyruvate to be integrated into the tricarboxylic acid cycle, melas patients have increased susceptibility to lactic acidemia under increased metabolic stress.4 therefore, general anesthesia, medications used for anesthesia, and surgery can cause deterioration of clinical manifestations in mms because of increased metabolic stress.4 other circumstances that can cause a metabolic burden in these patients and should be avoided or decreased include prolonged fasting, hypoglycemia, postoperative nausea and vomiting, hypothermia, prolonged tourniquets, acidosis, and hypovolemia.5 choice of fluids in melas patients remains controversial because whereas hypoglycemia can cause increased metabolic burden, glucose-containing fluids may not be optimal for avoidance of seizures.5 in one case report, glucose-containing fluid was given intraoperatively in a melas patient without adverse effect.11 also, owing to the predisposition of these patients to lactic acidosis, lactated ringer’s solution may not have been the best choice of intravenous fluids in this patient.11,12 according to the malignant hyperthermia association of the united states (mhaus), the first association between mms and malignant hyperthermia was suggested owing to the similar presenting clinical features, such as acidosis.13 however, recommendations from mhaus state that avoidance of volatile anesthetics is not necessary because of no increased susceptibility of patients with mms to malignant hyperthermia.13 avoidance of succinylcholine has been discussed because of one case report in 1985 in which life-threatening hyperkalemia occurred in a patient with mitochondrial dysfunction after its administration.13 however, just as mhaus suggests, no definitive genetic link has been shown between malignant hyperthermia and mitochondrial diseases such as melas.14 only central core disease, multiminicore disease, and king-denborough syndrome have a more definitive link to malignant hyperthermia.14 the use of succinylcholine in melas patients with muscle wasting can still predispose patients to hyperkalemia, but not as a result of the disease itself. most of the evidence in the literature is based on clinical case reports. various anesthetic techniques have been used in melas patients without adverse effects.15 in a retrospective review of 64 patients with mitochondrial disease (6 cases of melas), a variety of anesthetic techniques were used with no significant events such as unanticipated hospital admission, cardiac arrest, hypothermia, hyperthermia, prolonged post-anesthesia stay, increased lactic acidosis, or metabolic decompensation after exposure.15 these techniques included volatile anesthetic gases, neuromuscular blockers, and analgesics.15 in yet another case series review of patients with mitochondrial cytopathies, all 39 patients undergoing surgery were anesthetized with inhalational gases, local anesthesia, sedation, and general balanced anesthesia without any complications, which suggested that the routine use of intravenous or inhaled anesthesia did not influence the outcome.16 in a pediatric case series review by footitt et al, 38 patients with confirmed mitochondrial disease underwent 69 cases of general anesthesia.17 anesthetic agents included sevoflurane, propofol, midazolam, fentanyl, rocuronium, atracurium, alfentanil, anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 22 anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 23 and even 2 cases of use of succinylcholine with no adverse events noted intraoperatively.17 three adverse events were reported, none in melas patients, which included postoperative hypovolemia, renal impairment, respiratory failure, and metabolic acidosis.17 even though there has been wide documentation of the safety of multiple intravenous anesthetics, careful consideration must still be taken. although there are no documented cases of adverse effects from analgesics in melas patients, these patients may be at risk for decreased ventilatory response to hypoxia and hypercarbia and may suffer respiratory compromise from muscle wasting, and thus careful titration of analgesics is necessary.18 propofol has been implicated in propofol infusion syndrome owing to its inhibition of free fatty acids entering the mitochondria, impairing the electron transport chain, and inhibiting complex ii of the respiratory chain. propofol has been used in melas patients without any adverse side effects, but prolonged infusions can mimic mm symptoms such as lactic acidosis.19,20 use of muscle relaxants is also controversial. melas has been shown to cause focal segmental glomerulosclerosis; thus, it is imperative to take into consideration not administering any nephrotoxic agents.21 the anesthetic plan for the patient in the present case consisted of using cisatracurium owing to its elimination via hoffman elimination and ester hydrolysis. there has been one report of resistance to cisatracurium in a melas patient, but this patient received a full intubating dose of cisatracurium with full recovery of train-of-four and spontaneous ventilation.22 the effects of volatile anesthetics on the mitochondria are debated. they may have a protective effect on the mitochondria owing to ischemic preconditioning or they may inhibit nadh oxidation.20 multiple case reports have also documented the successful administration of regional anesthetics in melas patients without adverse effects, including spinal anesthesia for a femur fracture, combined general endotracheal anesthesia with epidural anesthesia for gastrectomy, spinal anesthesia for appendectomy, epidural anesthesia for postoperative pain control after laparotomy, combined general endotracheal anesthesia and postoperative epidural anesthesia for colectomy and ovariectomy, and epidural catheter placement for labor analgesia.12,19,23-26 it is still important for the anesthesia professional to consider any neurologic abnormalities of the spinal cord or peripheral nerves and to carefully consider coagulation status in this patient population. the patient in this case had an unsteady gait and normal coagulation studies, but because of his muscle wasting, respiratory compromise may have been a possibility if a regional anesthetic were chosen and if the level of block was too high. even though the obvious safety of regional anesthesia has been confirmed, local anesthetics still affect the mitochondrion. this presents another problem that the literature cannot answer regarding melas patients. local anesthetics such as bupivacaine have been shown to inhibit the mitochondrial respiratory chain complex i and cause oxidative phosphorylation uncoupling that is potentially detrimental to melas patients.27 upon induction, modified rapid sequence induction with cricoid pressure should be instituted in patients with gastric involvement such as nausea and vomiting.11 use of histamine-2 receptor antagonists and proton pump inhibitors may also be helpful to reduce aspiration risk.11 the patient in this case did not have any gastrointestinal dysfunction and thus this was not performed. a cardiovascularly stable anesthetic is best for melas patients because aerobic metabolism is already dysfunctional in this patient group.11 intraoperative considerations include maintaining normothermia in the melas patient owing to the impaired mitochondrial chain, which is responsible for heat maintenance. this includes monitoring temperature through a nasopharyngeal probe and warming intravenous fluids and using a forced air warmer.11 these interventions were used in the anesthetic plan for this melas patient. arterial blood gas analysis intraoperatively may be appropriate to check glucose and lactate levels. careful titration of muscle relaxants and opiates must be evaluated by using a peripheral nerve stimulator and spontaneous ventilation. adequate hydration is paramount. postoperative considerations must include possible metabolic disturbances, postoperative respiratory failure, and adequate analgesia to prevent acidosis. other considerations can include adequate control of nausea and vomiting and postoperative shivering. these patients should be monitored in the intensive care unit because of the potential for metabolic disturbances. ideally, clinical trials need to be performed specifically for melas patients with the same genetic defect and same presentation, which would require international collaboration to obtain an adequate sample size.28 these trials would need to investigate the pharmacology of anesthetic agents as it relates to melas and other mitochondrial disorders at a similar stage of disease progression and similar mitochondrial dna mutations with adequate power, statistically validity, and double-blinded randomization.28 anesthesia professionals could look to national consortia such as the north american mitochondrial disease consortium to recruit participants for future clinical trials.28 as more pathophysiologic advances occur in the understanding of mms, anesthetic management will improve.28 meanwhile, each melas patient and each patient with mm should be treated individually and the anesthetic plan should be adjusted accordingly. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 24 references 1. rivera-cruz b. mitochondrial diseases and anesthesia: a literature review of current opinions. aana j. 2013;81(3):237-245. 2. gurrieri c, kivela je, bojanic k, et al. anesthetic considerations in mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes syndrome: a case series. can j anesth. 2011;58(8):751-763. http://dx.doi.org/10.1007/s12630-011-9528-0. 3. wallace dc. mitochondrial diseases in man and mouse. science. 1999;283(5407):1482-1488. http://dx.doi.org/10.1126/ science.283.5407.1482. 4. finsterer j. central nervous system manifestations of mitochondrial disorders. acta neurol scand. 2006;114(4):217-238. http:// dx.doi.org/10.1111/j.1600-0404.2006.00671.x. 5. niezgoda j, morgan pg. anesthetic considerations in patients with mitochondrial defects. pediatr anesth. 2013;23(9):785-793. http://dx.doi.org/10.1111/pan.12158. 6. finsterer j. mitochondriopathies. eur j neurol. 2004;11:163-168. http://dx.doi.org/10.1046/j.1351-5101.2003.00728.x. 7. pfeffer g, chinnery pf. diagnosis and treatment of mitochondrial myopathies. ann med. 2013;45(1):4-16. http://dx.doi.org/10 .3109/07853890.2011.605389. 8. codier e, codier d. understanding mitochondrial disease and goals for its treatment. br j nurs. 2014;23(5):254-260. http:// dx.doi.org/10.12968/bjon.2014.23.5.254. 9. online mendelian inheritance in man. http://omim.org/entry/540000. updated january 2015. accessed march 8, 2015. 10. shipton ea. the perioperative anaesthetic management of patients with mitochondrial myopathies. cpd anaesth. 2006;8(1): 03-09. 11. sasano n, fujita y, so mh, sobue k, sasano h, katsuya h. anesthetic management of a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (melas). j anesth. 2007;21(1):72-75. http://dx.doi. org/10.1007/s00540-006-0449-y. 12. klingler w, lehmann-horn f, jurkat-rott k. complications of anaesthesia in neuromuscular disorders. neuromuscul disord. 2005;15(3):195-206. http://dx.doi.org/10.1016/j.nmd.2004.10.017. 13. malignant hyperthermia association of the united states. does mitochondrial myopathy (mm) increase an individual’s susceptibility to malignant hyperthermia (mh)? malignant hyperthermia association of the united states website. http:// www.mhaus.org/healthcare-professionals/mhaus-recommendations/mitochondrial-myopathy. accessed march 8, 2015. 14. litman rs. mh-associated diseases: who really needs a non-triggering technique? semin anesth. 2007;26(3):113-119. http:// dx.doi.org/10.1053/j.sane.2007.06.007. 15. song s, niezgoda j, parikh s. effects of anesthesia in patients with primary mitochondrial disorders. mitochondrion. 2013;13(6):908. http://dx.doi.org/10.1016/j.mito.2013.07.029. 16. moreira a, silva a, antunes m, neves i, costa c, santos p. anaesthesia in patients with mitochondrial cytopathy: 6 years series review. eur j anaesthesiol suppl. 2014;31:258-259. http://dx.doi.org/10.1097/00003643-201406001-00746. 17. footitt ej, sinha md, raiman jaj, dhawan a, moganasundram s, champion mp. mitochondrial disorders and general anesthesia: a case series and review. br j anaesth. 2008;100(4):436-441. http://dx.doi.org/10.1093/bja/aen014. 18. thompson va, wahr ja. anesthetic considerations in patients presenting with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (melas) syndrome. anesth analg. 1997;85:1404-1406. 19. maurtua m, torres a, ibarra v, deboer j, dolak j. anesthetic management of an obstetric patient with melas syndrome: case report and literature review. int j obstet anesth. 2008;17(4):370-373. http://dx.doi.org/10.1016/j.ijoa.2007.11.011. 20. finsterer j, segall l. drugs interfering with mitochondrial disorders. drug chem toxicol. 2010;33(2):138-151. http://dx.doi. org/10.3109/01480540903207076. 21. park js, baek cw, kang h, et al. total intravenous anesthesia with propofol and remifentanil in a patient with melas syndrome-a case report. korean j anesthesiol. 2010;58(4):409-412. http://dx.doi.org/10.4097/kjae.2010.58.4.409. 22. aouad mt, gerges fj, baraka as. resistance to cisatracurium in a patient with melas syndrome. paediatr anaesth. 2005;15:1124-1127. 23. blair mt, heard g. neuraxial anesthesia in melas syndrome. anaesth intensive care. 2011;39(6):1152-1153. 24. hsiao p, cheng y, hsiang-chiang t, chuang y, kao p, tsai s. spinal anesthesia in melas syndrome: a case with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes. acta anaesthesiol sin. 2000;38:107-110. 25. bolton p, peutrell j, zuberi s, robinson p. anaesthesia for an adolescent with mitochondrial encephalomyopathylactic acidosis-stroke-like episodes syndrome. paediatr anaesth. 2003;13(5):453-456. http://dx.doi.org/10.1046/j.14609592.2003.01001.x. 26. gentili me, raud c, enel d, henot m, bothereau h. combination of general anaesthesia and postoperative epidural analgesia in mitochondrial myopathy. ann fr anesth reanim. 2013;32(10):e149. http://dx.doi.org/10.1016/j.annfar.2013.07.798. 27. nouette-gaulain k, jose c, capdevila x, rossignol r. from analgesia to myopathy: when local anesthetics impair the mitochondrion. int j biochem cell biol. 2011;43(1):14-19. http://dx.doi.org/10.1016/j.biocel.2010.10.005. 28. kanabus m, heales sj, rahman s. development of pharmacological strategies for mitochondrial disorders. br j pharmacol. 2014;171(8):1798-1817. http://dx.doi.org/10.1111/bph.12456. summary of key points melas is a mitochondrial disorder due to a mutation in mitochondrial dna that causes a disruption in aerobic metabolism. melas has varied clinical manifestations including cardiac, neurological, and muscular. patients may have varied cardiac disturbances such as cardiomyopathy, may suffer from strokes, and can also have muscle wasting. • the malignant hyperthermia association of the united states does not recommend avoiding volatile agents in mitochondrial myopathy patients even though mitochondrial myopathy has a similar presentation of symptoms to malignant hyperthermia. • the safe use of an anesthetic technique in one type of mitochondrial myopathy does not translate to safety in melas. however, epidural anesthesia, spinal anesthesia, and general endotracheal anesthesia have all been used safely with various muscle relaxants and opioids in patients with melas in multiple case reports. • it is paramount for the anesthesia provider to remember that the stress of surgery and anesthesia itself can increase metabolic demand in these patients who are unable to meet the necessary energy requirements. therefore, a cardiovascularly stable anesthetic is appropriate. • avoidance of hypothermia, postoperative nausea vomiting, and lactate in intravenous fluids are mandatory interventions in melas patients. • careful titration of muscle relaxants, opioids, and other intravenous anesthetics is necessary because these patients are at risk for postoperative respiratory failure. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 25 volume 7no. 7 2019 educated hand publishing llc “the science behind the art” volume 7 no. 7 2019 anesthesia ejournal online issn 2333-2611 page 19 carnitine palmitoyl transferase 1a (cpt1a) deficiency, the arctic variant amber l. m. patson, bsn, srna affiliation: texas christian university abstract carnitine palmitoyl transferase 1a (cpt1a) is a crucial enzyme needed for mitochondrial fatty acid oxidation and is fundamental for appropriate metabolic responses to prolonged fasting. under normal conditions, the human body guarantees a constant energy supply by metabolizing glucose for energy in the short term, and by oxidizing fatty acids into ketones during long term fasting or starvation. fasting induces the breakdown of hepatic glycogen supply into glucose. continued fasting eventually leads to glycogen depletion followed by a decrease in serum glucose and insulin levels. this decrease then activates hormone-sensitive lipases located in adipose tissues and causes the release of free fatty acids into the blood. normally these free fatty acids would undergo beta-oxidation and the krebs cycle to produce energy; however, cpt1a deficiency results in about an 80% decreased activity of the cpt1a enzyme. this decreased cpt1a activity causes an inability to utilize fatty acids as energy and leads to a significant hepatic glycogen depletion during periods of fasting. preoperative fasting in these patients may result in vomiting, lethargy, hypoketotic hypoglycemia, seizures, liver failure, and an increased risk for respiratory illnesses that place this population at increased perioperative risk. interventions include, but are not limited to, parent education and prevention techniques, early recognition of symptoms, prompt treatment with glucose, and even surgery cancellation. cpt1a deficiency is found in circum-arctic populations such as alaskan inupiat and yupik, canadian and greenland inuit, and siberian yupik and is also known as the “arctic variant” of cpt1a. once thought of as a rare disorder, the introduction of tandem mass spectrometry (ms/ms) to alaska newborn screenings in 2003 revealed that the polymorphism c.1436c>t variant in the cpt1a gene has an incidence as high as 80% in specific regions of alaska. as of 2011, an estimated 700 alaska native infants born each year are homozygous for the c.1436c>t arctic variant. to safely care for this patient population throughout the perioperative period it is important for anesthesia professionals, in alaska and other arctic regions, to understand what the arctic variant of cpt1a is, who it affects, the anesthetic implications, and the recommended interventions for treating and preventing symptoms. aej p o w e rp o in t t e m p la te © 2 0 0 9 t e x a s c h r is t ia n u n iv e rs it y , c e n te r fo r in s t ru c t io n a l s e rv ic e s . f o r e d u c a t io n a l u s e o n ly . c o n te n t is th e p ro p e r ty o f th e p re s e n te r a n d th e ir r e s o u rc e s . introduction: • cpt1 is a mitochondrial enzyme responsible for the first step in fatty acid oxidation. • cpt1a is the isoform of cpt1 found in the liver.1 • cpt1a catalyzes the rate limiting step that imports long chain fatty acids into the mitochondrion, allowing for the production of ketones and subsequent atp energy from the breakdown of fat.2 • cpt1a arctic variant is an inherited autosomal recessive variant resulting in 80% decreased activity of the cpt1a enzyme.3 • the c.1436c>t variant occurs in 26% 80% of arctic populations including alaska, canada, greenland and siberia.4,5 background physiology: • normally, during periods of fasting, the body initially breaks down the hepatic glycogen supply into glucose.4 once glycogen is depleted, the decrease in serum glucose and insulin levels activate hormone-sensitive lipases, located in adipose tissues, triggering the release of free fatty acids.4 • free fatty acids enter cells but cannot enter the mitochondria until converted by acyl-coa synthetase into fatty acyl-coa. • mitochondrial porins then allow fatty acyl-coa through the outer membrane and into the intermembrane space where cpt1 catalyzes the acyl group of fatty acyl-coa to l-carnitine, forming acyl-carnitine and recycling the coa to be used again.6, 7 • the acyl-carnitine then crosses into the mitochondrial matrix via the transporter carnitine-acyl-carnitine translocase (cact).6, 7 • once in the mitochondrial matrix, cpt2, located on the inner mitochondrial membrane, will catalyze the conversion of acylcarnitine back into a fatty acyl-coa.6, 7 • the fatty acyl-coa undergoes beta oxidation to form acetyl-coa and enters the citric acid cycle (krebs) where electrons are removed and transported to the electron transport chain in order to produce atp.7,8 consequences of the arctic variant • this loss of activity may impair fasting ketogenesis and gluconeogenesis under certain conditions1,2,4,9,10 by limiting the amount of fatty acids that can be transported into the liver’s mitochondria to undergo beta oxidation. • symptoms are often triggered by fasting, especially if an illness or extreme stress is co-existing. symptoms may include: vomiting,1 lethargy,3 hypoketotic hypoglycemia,3,11 seizures,11 jitteriness, and poor feedings.3 • in 2003, tandem mass spectrometry (ms/ms) was utilized to identify the c.1436c>t variant on newborn screening.9 however, due to only a 10% detection with ms/ms, all newborns in alaska now undergo universal dna testing for the arctic variant.2,10 who it affects? • the arctic variant is the most common allele of cpt1a among yupik and inupiat alaska native people, canadian and greenland inuit, and indigenous people of eastern siberia.10 • evidence suggest that the arctic variant underwent positive selection among circum-arctic populations.5,10 • the arctic variant is thought to be mostly a concern in newborns, infants, young children and the elderly, as they potentially are unable to tolerate fasting in the presence of an illness or extreme stress. prevalence in alaska natives • data is from newborn screenings from july 2016 to present • all babies from alaska: 26% homozygous and 35% heterozygous2, 3 • northern (inupiat) and western (yupik) alaska: 51% homozygous and 47% heterozygous2, 3 • allele frequency: 0.72,3 • approximately 51% of alaska native infants born in western and northern alaska are homozygous for the cpt1a arctic variant, this equals around 700 babies every year.10 • some regions were found to have an incidence as high as 80% of native individuals being homozygous for the arctic variant.4 carnitine palmitoyl transferase, type 1a arctic variant (cpt1a arctic variant) amber l. m. patson, bsn, rn, srna, texas christian university references 1) hirschfeld, m. the arctic variant of cpt-1a. yukon-kuskokwim health corporation. retrieved from: https://yk-health.org/images/3/36/arctic-variant-cpt-1.pdf accessed february 1, 2019. 2) koeller, d. use of dried blood spots to study the arctic variant of cpt1a. newborn screening translational research network. retrieved from: https://nbstrn.org/sites/default/files/koeller.pdf published april 25, 2013. accessed january 27, 2019. 3) gessner bd, gillingham mb, johnson ma, et al. prevalence and distribution of the c.1436c-->t sequence variant of carnitine palmitoyltransferase 1a among alaska native infants. j pediatr. 2011;158(1):124-129. doi:10.1016/j.jpeds.2010.07.031. 4) gillingham mb, hirschfeld m, lowe s, et al. impaired fasting tolerance among alaska native children with a common carnitine palmitoyltransferase 1a sequence variant. mol genet metab. 2011;104(3):261-264. doi:10.1016/j.ymgme.2011.06.017. 5) clemente fj, cardona a, inchley ce, et al. a selective sweep on a deleterious mutation in cpt1a in arctic populations. am j hum genet. 2014;95(5):584-589. doi:10.1016/j.ajhg.2014.09.016. 6) adeva-andany mm, calvo-castro i, fernandez-fernandez c, donapetry-garcia c, pedre-pineiro am. significance of l-carnitine for human health. iubmb life. 2017;69(8):578-594. doi:10.1002/iub.1646.pmid:28653367. 7) rufer ac, thoma r, hennig m. structural insight into function and regulation of carnitine palmitoyltransferase. cell mol life sci. 2009;66(15):2489-2501. doi:10.1007/s00018-009-0035-1. 8) guyton, a. c, & hall, j. e. (2016). textbook of medical physiology-13th edition. chapter 68 and 69. philadelphia: elsevier. 9) gessner bd, wood t, johnson ma, richards cs, koeller dm. evidence for an association between infant mortality and homozygosity for the arctic variant of carnitine palmitoyltransferase 1a. genet med. 2016;18(9):933-939. doi:10.1038/gim.2015.197. 10) koeller, d. diet and the cpt1a arctic variant: impact on the health of alaska native children. newborn screening translational research network. retrieved from: https://www.nbstrn.org/sites/default/files/nbstrn_6.1.17_koeller.pdf published june 14, 2017. accessed january 28, 2019. 11) gessner bd, gillingham mb, wood t, koeller dm. association of a genetic variant of carnitine palmitoyltransferase 1a with infections in alaska native children. j pediatr. 2013;163(6):17161721. doi:10.1016/j.jpeds.2013.07.010. 12) fatty acid oxidation disorders: carnitine palmitoyl transferase, type 1a arctic variant. screening, technology and research in genetics (star-g), expanded newborn screening using new technologies. financial, ethical, legal and social issues (felsi). retrieved from: https://www.newbornscreening.info/parents/fattyaciddisorders/cpt1av.html#5 updated december 18, 2014. accessed march 2, 2019. 13) jardine, b, hirschfeld, m, schumacher, a. alaska native medical center. pocket guide to alaska native pediatric diagnoses: review of diagnoses rarely seen in other populations. retrieved from: http://anmc.org/files/pocket-guide-to-alaska-native-pediatric-diagnoses_web-1.pdf published spring 2016. accessed february 26, 2019. 14) syed, f, turner, h, alghamdi, f, tumin, d, tobias, j, wani, t. anesthetic management of a patient with carnitine-acylcarnitine translocase deficiency. n am j med case. doi:https://doi.org/10.14740/jmc3044w 15) lemas dj, wiener hw, o'brien dm, et al. genetic polymorphisms in carnitine palmitoyltransferase 1a gene are associated with variation in body composition and fasting lipid traits in yup’ik eskimos. journal of lipid research. 2012;53(1):175-184. doi:10.1194/jlr.p018952.pmid:22045927. anesthesia discussion/recommendations: pre-operatively: • it is important to know when a av-cpt1a child last ate as they have different metabolic needs. parents should be instructed to have the child drink breastmilk or clear liquids such as apple juice about 4 to 6 hours prior to surgery.12 • children may receive midazolam accompanied with juice, serving dual purpose of anxiolysis and glucose. • note child’s mental status and behavior. if showing symptoms of hypoglycemia, check blood sugar. • if the child is hypoglycemic, surgery may need to be cancelled. the child may need hospital admission to correct metabolic status by receiving intravenous (iv) or nasogastric (ng) administration of glucose.13 a standard maintenance rate of dextrose containing iv fluids is usually sufficient.13 intra-operatively: • blood glucose levels should be checked and maintained.14 • inpatient avcpt1a children should continue glucosecontaining iv fluids intra-operatively. • concerns of malignant hyperthermia are valid with mitochondrial enzymatic defects however, the use of volatile agents was found to be safe in this population.14 • propofol provides a large lipid load and may impair mitochondrial electron transport leading to development of propofol-infusion syndrome and severe metabolic acidosis.14 it is prudent to limit the use of propofol and then use a volatile agent for the maintenance of anesthesia.14 post-operatively: • a dextrose infusion should be considered for deterioration in neurologic status during the postoperative period (vomiting, lethargy, or change in mental status).14 theories supporting the evolutionary selective sweep of the arctic variant • the arctic variant in cpt1a causes decreased inhibitory effect of malonyl-coa on fatty-acid beta-oxidation, compensating for decreased ketogenesis.5 • lemas et al, suggested that the arctic variant c.1435c>t polymorphism may exert a cardioprotective role in the alaska yup’ik population by increasing high-density lipoproteins (hdl) cholesterol, and reducing adiposity.9,15 • the large amounts of n-3 polyunsaturated fatty acids (pufa) found in arctic populations diet, increases the activity of cpt1a.9 selecting for the c.1436c>t mutation and a decrease in cpt1a activity may provide protection against the overproduction of ketone bodies4 and deadly ketoacidosis. • interaction between high n-3 pufa diet and homozygosity for the arctic variant is basis for the “healthy obesity” phenotype in the yup'ik and inuit populations on traditional diets.9 othis includes low triglyceride levels, reduced c-reactive protein, and high circulating hdl-cholesterol.9 care of children with cpt1a arctic variant: avoid prolonged periods without food12 • recommended no more than 6-8 hours without eating12 • a baby/infant may need to be woken up to nurse/eat12 if the child is sick: •children with cpt1a arctic variant who are sick need to drink fluids with glucose, even if they do not feel hungry:12 • juice • sports drinks such as gatorade • oral electrolyte solution such as pedialyte parents/guardians should call a health care provider if: • their child is sick and unable to eat or drink glucose-containing fluids for greater than 6-8 hours12,13 • their baby/child seems sleepier than normal harder to wake up, seems confused, or is excessively irritable12 • the child has any of these symptoms:12 • poor appetite • low energy or excessive sleepiness • vomiting • diarrhea • an infection • a fever •the child may require intravenous (iv) infusion, or nasogastric (ng) administration of a glucose containing solution.13 case description: • a 5-year-old, 19.5 kg, 105 cm, male was scheduled for dental restoration • pmh: negative, except a diagnosis of cpt1a arctic variant • no known drug allergies • psh: circumcision without complications • vital signs were unremarkable • no pre-operative labs were ordered • anesthesia plan: 10 mg of oral midazolam (versed) and 250mg of oral acetaminophen (tylenol) followed by 30-60 mls of apple juice, general endotracheal anesthesia anesthetic management • on arrival to the operating room (or), the staff utilized storytelling and distraction techniques to place monitors • inhaled induction with nitrous oxide 1.5 l/min with oxygen 3.5 l/min and sevoflurane 8% at a flow rate of 10 l/min. a 22-gauge peripheral intravenous catheter was placed • general anesthesia was induced with fentanyl 10 mcg, propofol 50 mg, and dexmedetomidine 2 mcg • oxymetazoline and water-based lubricant applied to both nares, #4.5 nasal rae cuffed endotracheal tube was placed easily in the patients right nare • maintained using sevoflurane 2% end-tidal concentration in a mixture of nitrous oxide 1.5 l/min with oxygen 3.5 l/min • spontaneous respirations returned quickly and placed on pressure support ventilation • dexamethasone 4 mg was administered • blood glucose level checked and resulted: 112 mg/dl • dexmedetomidine 2 mcg iv administered three additional times during anesthesia maintenance for a case total dose of 8 mcg • ondansetron 2 mg was administered intravenously at end of case • extubation successful and transferred to the post anesthesia care unit (pacu) • pacu stay uneventful, vss, patient woke up crying, after about 20 minutes was transferred to stage 2 recovery area to be with parents • parents educated by staff about providing a source of glucose to the child after discharge, monitoring behavior for hypoglycemia, and when to bring the child back to the hospital alaskool.org. online materials about alaska native history, education, languages, and cultures. alaskool central: languages. retrieved from: http://www.alaskool.org/language/languageindex.htm accessed february 28, 2019. this project did not require irb review per 45 cfr part 46. anesthesia ejournal www.anesthesiaejournal.com volume 7 no.7 2019 page 20 the use of cognitive task analysis to improve anestheia skills training for postoperative extubation kären k embrey crna, ed.d assistant professor of clinical anesthesiology; assistant director for clinical services, program of nurse anesthesia, keck school of medicine, university of southern california, los angeles, ca. kenneth yates ed.d associate professor of clinical education; director for program evaluation, rossier school of education, university of southern california, los angeles, ca. keywords: cognitive task analysis, extubation training, expertise and anesthesiology abstract this study examines knowledge gains in 25 nurse anesthesia trainees, following the implementation of a novel instructional design, which incorporated cognitive task analysis (cta) to teach an adult postoperative extubation procedure. cta is a knowledge elicitation technique employed for acquiring expertise from domain specialists to support the effective instruction of novices. instruction guided through cta is effective in improving surgical skills training for medical students and surgical residents. the standard, current method of teaching clinical skills to novices in nurse anesthesia practice relies on recall-based instruction from domain experts. however, this method is limited by the constraints of expertise, including automation of procedural knowledge by the expert practitioner. automated knowledge escapes conscious awareness and access, thus impeding clear explication of comprehensive essentials for task execution during instruction. cta guided instruction has been shown to maximize conceptual, declarative and procedural knowledge gains in aej novice practitioners by clearly explicating the essentials employed when experts execute tasks. knowledge gains for the task of postoperative extubation in 13 junior and senior nurse anesthesia trainees were compared to those of 12 trainees, receiving standard instruction. the study results indicate that cta-based instruction has a positive and significant effect on procedural knowledge gains in the novice anesthetist. video: cognitive task analysis introduction “there are things that we know but cannot tell. this is strikingly true for our knowledge of skills.”1 healthcare education must incorporate processes to ensure optimal patient outcomes as well as best practices for trainee education.2 this is especially important for complex cognitive tasks or skills such as postoperative tracheal extubation. this task is strategically performed to facilitate resumption of respiration, via the normal anatomical airway once mechanical assistance or an artificial airway is unnecessary for effective postoperative patient ventilation.2 the training of novice practitioners for the performance of this critical skill must include both the conceptual knowledge (what to do and why to do it) and procedural knowledge (when and how to do it). skills training however, may present unique pedagogical challenges to the expert charged with educating novices, owing to the limitations of automated or implicit knowledge which is not readily accessible or shared by expert practitioners.3 seminal research in the acquisition and development of expertise suggests that the development of expertise occurs roughly over 10,000 hours of deliberate practice in a specific domain, where performance feedback and improvement are continuous.4,5 however over time, knowledge in the expert practitioner becomes unconscious or implicit and automated.6 moreover, research in educational psychology suggests that experts routinely omit up to 70% of essential information for task execution when they rely on recall during clinical instruction.7,8,9 such omissions in clinical instruction may be counteracted by the use of cognitive task analysis (cta) methods. cognitive task analyses are methods used to elicit the full spectrum of expertise necessary for complex skill execution in order to improve instructional design for the teaching of these skills. in the training of novice anesthesia practitioners, the standard current method of teaching clinical skills such as postoperative extubation relies heavily on recall-based instruction from domain experts, either in the operating room, during case management, or in the simulation laboratory. complex cognitive tasks such as those necessary in the performance of postoperative extubation integrate both controlled, conscious (conceptual) and unconscious or automated (procedural) knowledge. this knowledge must be strategically executed to achieve optimal task outcomes during task execution.10 while experts may perform complex tasks and execute procedures with exceptional ease and efficacy, they often omit the details of just how they perform these tasks because they don’t consciously access or share automated aspects of the task. advances in cognitive science however may offer a solution to the problem of procedural and declarative knowledge transfer from experts to novices, through the application of cta methods. cognitive task analysis is a systematic approach for capturing the full spectrum of knowledge that experts employ during the execution of complex tasks. this method of expertise elicitation explicates both the observable actions and the cognitive processes (decisions, judgments, and analyses) experts use to solve difficult problems and perform complex tasks.11 there are five steps to conducting cta.12 first, the knowledge analyst becomes familiar with the domain and tasks to be captured. then, each type of knowledge within the task and sub-tasks is identified. in the third step, the analyst conducts a semi-structured interview to capture the conceptual knowledge related to the task, as well as the action and decision steps the expert uses to perform the task. next, the information collected is analyzed and verified by the aej expert. finally, the results are formatted for the intended use, such as a protocol for performing the task, job aids, and checklists. when cta is conducted with multiple experts, often the 70% rule of information omissions can be reversed.13,14 when incorporated into training, the application of cta elicited expertise may offer an improvement over conventional clinical instruction methods that primarily rely on expert recall,9 by delineating task rules and formulating highly accurate and exhaustive algorithmic descriptions of challenging cognitive tasks.15 the application of cta techniques has proven successful in improving learner outcomes in medical and surgical skills training16,9 as well as improving direct patient outcomes following surgical skills training.17 the purpose of the current study was to determine if cta based instruction of postoperative tracheal extubation is more effective than conventional clinical instruction provided to anesthesia trainees, as measured by conceptual and procedural pre and posttests aimed at assessing both explicit (conscious) and implicit (unconscious) knowledge. the study compared the comprehensive knowledge gains of students receiving postoperative extubation training following either standard recall-based instruction or an experimental instructional design using a cta technique. the following questions were explored: 1. do participants in the experimental group demonstrate greater conceptual knowledge (what to do and why to do it) on postoperative tracheal extubation than participants in the control group? 2. do participants in the experimental group demonstrate greater procedural knowledge (when and how to do it) in performing postoperative tracheal extubation than participants in the control group? the second question further examined measures on task accuracy, timing for task completion and the correct sequencing of subtasks within the main task of postoperative tracheal extubation. materials and method this randomized experimental study employed a design based on content captured by the use of a cognitive task analysis to elicit knowledge from anesthesia experts for the task of adult, awake postoperative extubation. the cta elicited expertise was then used to develop the experimental instructional curriculum and the assessment tool used in the quantitative assessments of instructional outcomes. the cta procedure for knowledge elicitation followed the five steps outlined in clark et al 15 three anesthesia experts were individually interviewed to elicit knowledge about the action and decision steps, indications and contraindications, standards, and equipment for the awake adult postoperative tracheal extubation task. the experts were also asked about how to manage difficult or unexpected occurrences during extubation as well as the conditions under which they would defer extubation. additional information regarding other sensory cues and input during task and subtask execution was also gathered and included sounds, smells, and tactile input surrounding task execution. during a verification process, the interviewees subsequently reviewed and clarified the coded data obtained in the interviews and represented by a written protocol for performing the procedure. individual protocols from the three experts were then aggregated to generate a “gold standard” protocol for extubation that was reviewed by three other anesthesia experts. the resulting cumulative data were employed to generate the instructional protocol and assessment materials, including an algorithmic instructional outline explicating exhaustive if…then scenarios which could arise during awake adult postoperative extubation and a checklist for evaluating the post instructional performances of trainees. following institutional review board approval and informed aej consent, 25 student registered nurse anesthetist volunteers were randomized to stratified control or experimental instructional groups. the volunteers included 14 junior students (novices) in their first semester of training, who had not previously performed tracheal extubation, and 11 senior students (intermediates), who had each previously performed roughly 100 supervised extubations. the experimental group of students (7 juniors, 6 seniors) received instruction employing the cta guided curriculum, during a demonstrated task execution, while the control group (7 juniors, 5 seniors) received conventional recall-based instruction during a demonstrated task execution. except for the cta-derived content for the experimental group training, the instructional design, development, and implementation were identical for both groups. instruction on tracheal extubation for both the experimental and control groups was conducted in a state-of-the-art, high fidelity, simulation laboratory using the metiman® (cae healthcare) human patient simulator, which reacts to interventions in real time with dynamic and nuanced, high fidelity human physiological responses. experimental participants were instructed using the cta guided curriculum generated in the pre-study period. instruction was delivered during a simulated patient extubation with the instructor following the cta generated protocol. controls received the standard recall-based instruction for postoperative tracheal extubation, which included standard recall-based instruction on the task during a simulated patient extubation. instruction and evaluations of both the control and experimental groups of trainees were videotaped for analysis and data coding. task instructors, both senior faculty members, shared similar experience with clinical instruction in the domain of nurse anesthesia practice and had similar expertise in the use of the simulation laboratory. both instructors employed a think aloud method of communication during instruction. all study participants underwent uniform pre-briefing and debriefing sessions in keeping with the simulation center’s policies for lab participation and training and testing content confidentiality. students’ declarative knowledge was assessed both before and after the training intervention via written exam. both the pre and posttest incorporated a case based patient scenario for adult, awake extubation and included questions such as the following to assess declarative knowledge: 1) name 6 pieces of equipment necessary for safe postoperative extubation, 2) what are 4 indications that your patient is ventilating effectively on her own once the ventilator has been turned off, 3) put the following 6 subtasks into the correct order for the safest postoperative extubation: a) suction the oropharynx, b) remove the patient’s protective eye tape, c) take the patient off of the ventilator to evaluate how well she is able to breathe on her own, d) reverse the neuromuscular blocking agent, e) evaluate the train of four response, f) place an oral airway. a total of 10 such questions were included on the written pre and posttest. procedural knowledge was assessed by 2 trained observers using the cta based checklist during participant task execution in the simulation laboratory following instruction though conventional or experimental method. the checklist was used to assess the execution of the extubation sequence and the subtasks within the 4 delineated temporal categories as seen below in figure 1. the checklist developed for this purpose was the simplest outline of the necessary steps for a safe extubation. the exhaustive algorithm for extubation which was developed from the cta interviews with anesthesia experts could be used to generate expanded content and checklists for future task training by evaluating any number of if…then situations that might arise during an extubation sequence. more advanced checklists could be used to assess additional conceptual knowledge or strategic decision making during the process of extubation such as in the management of deep extubation or extubation for the patient with suspected airway edema. the simple extubation sequence checklist used for this experiment included content reflecting decision making strategies such as: if the surgeons have completed the surgery but the train of four monitor indicates that aej the patient has 0/4 twitches then begin tapering the inhalation agent but keep the patient asleep until the train of four monitor indicates neuromuscular blocking agents can be antagonized. the temporal categories for the subtasks of the simplified checklist for postoperative awake extubation included 1) begin tapering anesthetics in response to cues from surgeons, 2) position patient for safe emergence and extubation (ensure patient is not in trendelenberg, lithotomy or other unfavorable position), 3) emerge the patient and extubate the trachea, and 4) monitor and confirm post extubation respiratory homeostasis. the students’ performances were assessed by 2 trained observers to evaluate whether they did or did not perform each of the subtasks in these temporal categories, and whether their performances were executed correctly or not. for transparency of decision making, student participants employed a think aloud method of communication during task execution. figure1. procedural checklist for adult, awake postoperative extubation temporal frame and sub task for adult awake extubation circle if not done (nd) or if done incorrectly (di) place check mark if done correctly comments 1. begins tapering anesthesia in response to cues from surgeons a) checks train of four response b) administers neuromuscular block reversal c) suctions oropharynx d) monitors for spontaneous ventilation nd di nd di nd di nd di 2. positions patient for safe emergence; extubation a) employs universal precautions b) places oral airway c) returns patient to head of bed; supine d) ensures patient is safely restrained e) removes eye tape f) turns o 2 to 100% g) monitors alveolar concentration of gases nd di nd di nd di nd di nd di nd di nd di 3. emerges the patient and extubates the trachea a) assesses the patient for emergence; observes for return of reflexes b) does not extubate when patient remains in stage ii c) check respiratory rate is 830/ min, checks tidal volume (tv) is appropriate (5cc/kg); etco2 < 45cmh2o d) assists ventilation by hand when spontaneous ventilation is inadequate e) reassesses respiratory status for rate and minute ventilation. rate 830/min, tv appropriate &etco2 < 45cmh2o f) looks for regularity of respiratory rate g) confirms patient is in stage i using specific criteria (such as eye opening, hand squeeze, head lift, tongue projection) h) places circuit mask, syringe & suction in appropriate reach i) loosens tape on face j) deflates endotracheal tube (ett) cuff k) increases positive pressure ventilation; squeezes bag or sets apl valve to 20cmh2o pressure and removes ett from trachea nd di nd di nd di nd di nd di nd di nd di nd di nd di nd di nd di 4. monitor and confirm post extubation respiratory homeostasis a) immediately following extubation places the circuit mask on the patient’s face and confirms co2/ mist (pt is free of obstruction) b) if not, repositions the mask / checks for breath holding/ provides chin lift c) if obstruction is suspected places oa(uses tongue blade or na as needed) d) suctions again post extubation if needed e) confirms respiratory homeostasis & places pt on transport mask at > 6lpm f) raises the head of the bed, keeps o2 saturation monitor in place until leaving the or g) monitors patient during transport to pacu – watches for mist in the mask/ chest rise/ skin color and listen for obstruction nd di nd di nd di nd di nd di nd di nd di aej figure 2 below shows the timeline for the study which was conducted over two days. figure 2. study flow and timeline results the purpose of this study was to determine if cta based instruction of postoperative tracheal extubation is more effective than conventional clinical instruction by domain expert provided to anesthesia trainees, as measured by conceptual and procedural pre and posttests. for all statistical analyses in this study a 95% confidence level (p < 0.05) was employed. using independent t-tests, comparisons were made of the differences between the control and experimental groups’ performances for both declarative and procedural knowledge. the study also evaluated the expected and observed performances of students in both control and experimental groups who had prior experience performing extubation and compared these to those of students without prior experience performing the task. to examine effects of prior knowledge on procedural performance for correct subtask sequencing, x2 values were calculated using the raw data from the assessments of the experimental senior and junior students 0700 0720-0735 0735-0800 0800 – 0825 0830-1045 1045-1115 1115-1130 and the control senior and junior students. these x2 values were then tested for significance. question 1: do participants in the experimental group demonstrate greater conceptual knowledge (what to do and why) on postoperative tracheal extubation than participants in the control group? in the assessment of declarative knowledge, an independent samples t-test demonstrated no significant differences in baseline or post intervention declarative knowledge on extubation between the control and experimental groups: t (23) = -.843 (p= .408), thus demonstrating equivalence in conceptual knowledge prior to the training, and no significant gain by the experimental group on conceptual knowledge during the training. question 2: do participants in the experimental group demonstrate greater procedural knowledge (when and how to do it) in performing postoperative tracheal extubation than participants in the control group? for this question, task accuracy represented the measure of procedural knowledge. findings demonstrated a significant difference for juniors who received cta guided instruction (70.46 ±12.43), compared to the control group of juniors (60.71 ± 6.99) (p =.047) who received standard recallbased instruction. there was also a trend toward improvement in task accuracy in the experimental senior students’ performances compared to control senior performances, though this was not a statistically significant finding. the second research question further examined measures on task expediency by examining the time required to complete the task, and the correct sequencing of subtasks within the main task of postoperative tracheal extubation. subtasks included measures such as suctioning the oropharynx, antagonizing the neuromuscular blocking agents and assessing for adequate patient ventilation. for task expediency, a significant level of expediency was found (8.83 minutes ± 1.33) for the experimental group of seniors and juniors when compared to their control counterparts aej (10.75 minutes ± 2.34) (p = .022). juniors in the experimental group outperformed control juniors; (9.00 minutes ± 1.291) versus (11.43 minutes ± 2.637) (p = .049) in task expediency. a comparison between the performances of all junior and all senior students in the study for the execution of correct subtask sequencing of the extubation skill set was performed. the findings were significant x2 (1, n = 25) = 8.766, p = .003, and not unexpected as all senior students had performed roughly 100 extubations before the study. however, the difference in expected and observed performance was particularly statistically significant for the senior experimental students (x2 = 6.198, p = .013). these results may demonstrate that cta guided instruction is effective in improving procedural knowledge gains even in the learner with higher levels of prior experience, in whom the task may already be automated to some extent. under conditions of prior experience and task automation, instructors face the challenge of students with prior beliefs and methods which must be “unlearned” to facilitate effective instruction. the cta guided instructional format appeared to effectively meet this challenge. in summary, junior students, task novices demonstrated significant improvements on task accuracy as well as task expediency following cta guided instruction on adult, awake postoperative tracheal extubation. these findings support the benefits of cta guided instruction for novice practitioners. interestingly, more experienced seniors in the experimental group also demonstrated a trend toward improvements in task accuracy and expediency when compared to control group seniors. experimental senior students also demonstrated statistically significant improvements in correct sequencing for the subtasks of extubation, despite the burden of their prior knowledge which had to be unlearned. this important finding may demonstrate the added benefit of cta guided instruction for students or practitioners with higher levels of prior knowledge, in whom it can be assumed, task automation is already established to some degree. table 1: percent task accuracy following instruction table 2: task expediency following instruction table3: correct subtask sequencing following instruction discussion the purpose of this study was to examine the effectiveness of cta guided instruction compared to conventional recallbased clinical instruction delivered to student registered nurse anesthetists for adult, awake postoperative tracheal extubation. the standard, current method of teaching clinical skills in the operating room or simulation lab to novices in medical and nursing specialties, including anesthesiology, relies on recallbased instruction from domain experts. instruction by experts however is limited by task automation on the part of the expert practitioner. automated or unconscious knowledge is not readily accessible to the expert teacher and may inhibit explication of all the necessary subtasks and essentials for task execution during teaching. cognitive task analysis or cta is a comprehensive knowledge elicitation technique used for acquiring expertise and designing exhaustive protocols from information gained from domain specialists which can support the effective instruction of novices. the application of cta guided instruction has been demonstrated as successful in improving learner outcomes in medical and surgical skills training16,9 as well as improving direct patient outcomes following surgical skills training.17 findings from the current study demonstrate positive trends and statistically significant improvements in the performances of student registered nurse anesthetists learning the task of adult, awake postoperative tracheal extubation through cta guided instruction in the simulation laboratory, when compared to controls receiving conventional recall-based instruction. aej this is the first known study employing cta to inform instructional content for nurse anesthesia task training, and the study’s findings are positive and in keeping with other similar studies examining surgical skills training for residents and medical students. performance improvements in the anesthesia trainees were specifically significant for procedural knowledge gains in the areas of task accuracy, task expediency and subtask sequencing following cta-guided instruction. similar studies with larger participant pools may be required to more thoroughly evaluate the efficacy of cta-guided instruction for skill acquisition in nurse anesthesia training. references 1 polanyi m. personal knowledge. chicago, il: university of chicago press; 1962. 2 embrey kk. the use of cognitive task analysis to capture expertise for tracheal extubation training in anesthesiology [dissertation]. los angeles, ca: university of southern california; 2012. http://gradworks.umi. com/3513751.pdf. accessed september 22, 2013. 3 chi mt. two approaches to the study of experts’ characteristics. in: ericsson ka, charness n, feltovich pj, hoffman rr, eds. the cambridge handbook of expertise and expert performance. new york: cambridge university press; 2006:21–30. 4 ericsson ka, krampe rt, tesch-römer c. the role of deliberate practice in the acquisition of expert performance. psychol rev. 1993;100(3):363-406. 5 ericsson ka. deliberate practice and the acquisition and maintenance of expert performance in medicine and related domains. acad med. 2004;79(10):s70-s81. 6 clark re. yin and yang: cognitive motivational processes operating in multimedia learning environments. in: van merrienboer jj, ed. cognition and multimedia design. herleen, netherlands: open university press;1999. 7 feldon df, clark re. instructional implications of cognitive task analysis as a method for improving the accuracy of experts’ self-report. in: clarebout g, elen j, eds. avoiding simplicity, confronting complexity: advances in studying and designing (computerbased) powerful learning environments. rotterdam, netherlands: sense publishers; 2006:109-116. 8 pugh cm, santacaterina s, da rosa d, clark re. intraoperative decision making: more than meets the eye. j biomed informatics. 2011;3:486-496. 9 yates ka, sullivan me, clark re. integrated studies in the use of cognitive task analysis to capture surgical expertise for central venous catheter placement and open cricothyrotomy. in: symposium of the association for surgical education. boston, ma; 2011. 10 van merriënboer jjg, clark re, de croock mm. blueprints for complex learning: the 4c/id-model. ed technol res dev. 2002;50(2):39-61. doi: 10.1007/ bg02504993. 11 schraagen jm, chipman sf, shalin vl. cognitive task analysis. mahwah, nj: lawrence erlbaum associates; 2000. 12 clark re, feldon d, van merriënboer jjg, yates ka, early s. cognitive task analysis. in: spector jm, merrill md, van merriënboer jjg, driscoll mp, eds. handbook of research on educational communications and technology. 3rd ed. mahwah, nj: lawrence erlbaum associates; 2008:578-591. 13 crispen pd. identifying the point of diminishing marginal utility for cognitive task analysis surgical subject matter interviews [dissertation]. los angeles, ca: university of southern california; 2010. http://usc.summon.serialssolutions.com. accessed september 20, 2013. aej 14 chao cj, salvendy g. percentage of procedural knowledge acquired as a function of the number of experts from whom knowledge is acquired for diagnosis, debugging and interpretation tasks. int j hum compu interact.1994;6:221–223. doi:10.1080/10447319409526093. 15 clark re, pugh cm, yates ka, sullivan me. the use of cognitive task analysis and simulators for after action review of medical events in iraq. in: technical report produced under contract w81xwh-04-c-0093 from the u.s army medical research and materiel command. fort detrick, md; 2006. 16 sullivan me, ortega a, wasserberg n, et al. assessing the teaching of procedural skills: can cognitive task analysis add to our traditional teaching methods? am j surg. 2008;19:20–23. doi:10.1016/j.amjsurg.2007.08.051. 17 velmahos gc, toutouzas kg, sillin lf, et al. cognitive task analysis for teaching skills in an inanimate surgical skills laboratory. am j surg. 2004;1:114-119. aej2 propofol and ketamine for targeted muscle reinnervation after limb amputation: a case report angela hupman, bsn, srna ladan eshkevari, phd, crna keywords propofol, ketamine, tiva, targeted muscle reinnervation, phantom limb pain. abstract surgical procedures that require neuromuscular monitoring present unique challenges to the anesthesia provider. specific patient characteristics such as phantom limb pain or chronic opioid use can further complicate perioperative management. the following case presentation illustrates the anesthetic management of a patient exhibiting these complications who presented for surgery with a prior transhumeral amputation. nerve reassignment was planned with the eventual goal of a thought-controlled prosthesis. anesthesia was maintained by the combination of propofol and ketamine along with adjuncts such as hydromorphone, midazolam and glycopyrrolate. these drugs and similar anesthetic combinations cause minimal changes to neurophysiologic monitoring while decreasing various types of neuropathic pain and provide an effective alternative for treating patients with chronic pain. 3volume 2, no. 1 introduction targeted muscle reinnervation (tmr) is a ground-breaking procedure that gives upper extremity amputees the ability to control prosthetic limbs via reassigned nerves. approximately 50 such procedures have been performed worldwide, and the following case is the second to have been implemented at a large, metropolitan research hospital. instead of relying on residual muscle strength alone, tmr allows for movement stimulated by electromyogram (emg) nerve signals.1 prostheses are then controlled by simply thinking about desired actionsa process closely resembling life prior to amputation.1 choice of intraoperative anesthetic plays a considerable role both during and after the procedure. total intravenous anesthesia (tiva) shows tremendous ability to reach surgical and patient specific goals in regard to effective neuromonitoring and pain control. case summary a 49-year-old, 63 kg man presented for tmr after a motor vehicle accident that resulted in a transhumeral amputation. the following nerve transfers were planned: median to clavicular head of pectoralis major, ulnar to sternal head of pectoralis major, and radial to coracobrachialis. past surgical history included a posterior cervical spine fusion of c5-c6, as well as a rod placement in the right lower extremity. the patient suffered permanent contracture of the lower extremities as well as left upper extremity phantom limb pain. each of the following medications were prescribed 3 times per day: methadone 20 mg, carisoprodol 350 mg, baclofen 20 mg, gabapentin 600 mg, and nortriptyline 50 mg. every 4 hours, 10 mg of oxycodone was prescribed as needed and was taken at regular intervals daily. the preoperative chemistries, hematological values and coagulation profile were all within normal limits. vital signs were as follows: blood pressure 119/60 mm hg, normal sinus rate at 100 beats/min, respiratory rate of 16 breaths/min, saturation of peripheral oxygen (sp02) 100% (room air), pain score 7/10 (chronic, sharp). in the preoperative holding area, 2 mg midazolam were administered via an existing 20 gauge intravenous (iv) catheter. aej4 upon entering the operating room, standard monitors were placed, and 100% oxygen (o2) at 12 l/min was simultaneously delivered to the patient by face mask. after an initial set of vital signs was obtained, iv anesthetic induction was initiated with lidocaine 100 mg, propofol 120 mg, and ketamine 100 mg. due to the patient’s prior cervical spine injury, neck flexion and extension were avoided during supraglottic insertion of a size 5 laryngeal mask airway (lma). an end tidal carbon dioxide measurement of 36 mm hg was present upon the third breath, and air movement was auscultated bilaterally and equally. the o2 flow rate was decreased to 3 l/min, and the lma was secured prior to 90 degree rotation of the operative table. the airway was reassessed. an 18 gauge peripheral iv was aseptically placed in the right antecubital fossa. general anesthesia was maintained with a mixture of propofol 50 ml (10 mg/ml) and ketamine 0.5 ml (100 mg/ml). the infusion was initiated at a rate of 80 mcg/kg/min and titrated to 110 mcg/kg/min based upon response to surgical stimulus. a concurrent one-time dose of glycopyrrolate 0.2 mg was also administered. intermittent doses of hydromorphone were given according to sympathetic response, for a total of 6 mg throughout the case. spontaneous respirations resumed and were maintained between 8 and 15 breaths/min. the systolic blood pressure ranged from 100 to 125 mm hg, and the heart rate was between 95 and 105 beats/min. for the duration of the case, sp02 remained 100% with an intraoperative fraction of inspired o2 of 0.5. the patient did not receive neuromuscular blockers at any point. ondansetron 4 mg was also given. neuromonitoring was conducted via emg, motor evoked potentials (meps), and somatosensory evoked potentials (sseps) by a technician. upon emergence, the patient was transported to the postanesthesia care unit with o2 delivery by simple face mask at 6 l/min. the patient denied pain, nausea, or recall of the procedure. there were no untoward events. the patient recovered in the hospital 5volume 2, no. 1 for a single day, was discharged home, and had tentative plans to be fit for prosthesis in 6 months. discussion the anesthetic combination of propofol and ketamine was chosen for its beneficial impact on pain management and based on the need for neuromonitoring. procedures that require neurophysiologic monitoring of motor activity by way of meps and emgs dictate that neuromuscular blocking agents be used judiciously. train-of-four twitch height should be maintained around 30% or, clinically, 1 to 2 twitches.2 in contrast, ssep monitoring involves purely sensory-evoked information, and in such cases, skeletal muscle contraction and neuromuscular blocking agents do not need to be tightly regulated.2 since motor function was of concern, neuromuscular blocking agents were not used during this case. for further discussion, most anesthetic agents, not just those acting at the neuromuscular junction, can either suppress or enhance both the amplitude and latency of waveforms being recorded.3 halogenated volatile anesthetics produce a dose-dependent decrease in amplitude and increase in latency of mep signals.3 wang et al. reiterate this concept and describe that at levels greater than 0.5 minimum alveolar concentration (mac), inhalational anesthetics produce great variability in neurophysiologic readings.3 while use of propofol can also induce a dose-dependent effect similar to volatile anesthetics, the impact is much less severe, and the agent provides stable neuromonitoring conditions. additionally, the use of ketamine in conjunction with propofol has been shown to enhance signal waveforms.3 it is important to recognize that no matter the technique chosen, low mac inhalational agent, tiva, or a combination of both, abrupt changes in the concentration of these agents can challenge the validity of results and cause misinterpretation of the information provided.3 changes to the anesthetic technique should be avoided if possible, and when initiated, the changes should be communicated aej6 with the surgical team and the neuromonitoring technician. phantom limb pain is particularly hard to control and not well understood. it is believed that n-methyl-d-aspartate (nmda) receptors play a critical role in this pain pathway.4 since this is the same receptor antagonized by ketamine, its use with various types of neuropathic pain has been investigated. alviar et al. studied various pharmacologic interventions for this pain pathway and found dichotomous results in regard to ketamine’s benefits. while the agent did provide a significant amount of analgesia, the less desirable effects produced by dissociation of the thalamocortical and limbic systems led to increased secretions, hallucinations, loss of consciousness and sedation.4 with similar findings, sigtermans et al. evaluated the use of ketamine in decreasing symptoms of patients suffering from continuing pain, hyperalgesia, and allodynia. in the randomized, doubleblind, placebo-controlled study, 60 patients received either an infusion of low-dose ketamine or normal saline over 5 days and were followed for 12 weeks.5 according to the study findings, the low-dose ketamine infusion resulted in clinically significant reductions in pain for 11 weeks as compared to the placebo, but it also caused psychomimetic side effects, headache, and nausea.5 for all of these reasons, in this case, prior to ketamine administration, midazolam was given as a premedication to offset potential emergence delirium, and glycopyrrolate was given in conjunction to decrease muscarinic side effects. the patient did not report any phantom pain immediately postoperatively, nor did he have hallucinations. patients suffering from chronic pain undeniably present a challenge with respect to controlling perioperative discomfort. suboptimal relief is often encountered, especially with high doses of opioid taken on a long-term basis. loftus et al. suggest that perhaps the best way to treat an opioid-dependent patient is by tapping into opioid-independent pathways.6 in a randomized, double-blind, placebo-controlled study, the researchers evaluated 7volume 2, no. 1 patients with chronic pain undergoing major spine surgery, all of whom had been taking opioids for a minimum of 6 weeks. results indicated that patients in the treatment group, receiving ketamine, required decreased doses of opioid intraoperatively, immediately postoperatively, and at 6 weeks post-procedure (24% p = 0.006, 37% p = 0.029, and 71% p = 0.041 less opioid, respectively).6 of note, reductions in analgesic requirements did not coincide with any increases in undesirable side effects. loftus et al. conclude that ketamine’s beneficial role in treatment of chronic pain is not limited to antagonism of nmda receptors but incorporates other factors such as modulation of neurotransmitters associated with depression and reduction of opioid mu, kappa and delta receptor sensitization. conclusion use of propofol and ketamine for tmr was effective in meeting the surgical and anesthetic goals of this case. neuromonitoring was not compromised; the patient was adequately anesthetized, and the need for chronic pain control was addressed. use of propofol and ketamine in combination with adjunct medications such as midazolam, glycopyrrolate, and hydromorphone proves to be a suitable anesthetic plan for this and similar situations. the number of patients presenting for care following amputation will continue to grow. this anesthetic technique may be utilized for warriors returning home, those involved in traumatic injury, or anyone following the loss of a limb. amputees present following a variety of injuries, and many of them occur while serving in the united states military. the new york times recently explained that the utility of tmr for american service members is becoming increasingly apparent. more than 1570 soldiers lost limbs while serving in either iraq or afghanistan.7 these individuals will experience many inconveniences, including phantom limb pain and a reduction in overall independence that muscle reinnervation may improve. the marine corps member featured in the article underwent tmr and is now practicing aej8 daily activities with his new mechanical arm, as well as surfing, swimming and kayaking.7 it is important that anesthesia providers recognize the beneficial impact that these procedures can have on an individual’s quality of life and be able to provide effective anesthetic management for such cases. summary of key points procedures requiring neuromuscular monitoring present unique challenges to the anesthetist. further complications arise when patients suffer from neuropathic or chronic pain. when choosing an anesthetic plan to meet these goals, the following key points may be considered. »» propofol can cause dose-dependent decreases in amplitude and increases in latency; however, the effects are much less pronounced than with the use of volatile anesthetic agents. the use of propofol allows for fairly stable neuromonitoring conditions. »» in contrast to many other anesthetic agents, ketamine enhances neuromonitoring waveforms. »» ketamine antagonizes nmda receptors, which are believed to play a role in neuropathic and phantom limb pain. »» ketamine is an antagonist at various opioid receptors, making it an effective alternative in the treatment of chronic pain patients. »» regardless of the anesthetic technique employed, the provider should not abruptly change the anesthetic when neuromonitoring is being utilized. effective and ongoing communication between the anesthesia provider, surgeon, and neuromonitoring technician is crucial. author info (principal author) angela hupman, bsn, student registered nurse anesthetist, georgetown university nurse anesthesia program, washington, dc. angelahupman@gmail.com, (904) 742-6941 9volume 2, no. 1 (senior and corresponding author) ladan eshkevari, phd, crna, nurse anesthetist, assistant director, professor, georgetown university, washington, dc. eshkevl@georgetown.edu references 1 kuiken ta, li g, lock ba, et al. targeted muscle reinnervation for real-time myoelectric control of multifunction artificial arms. jama. 2009;301(6):619-628. doi: 10.1001/jama.2009.116. 2 seubert cn, mahla me. neurologic monitoring. in: miller r, ed. miller’s anesthesia. 7th ed. philadelphia, pa: churchill livingstone; 2010:1477-1541. 3 wang ac, than kd, etame ab, la marca f, park p. impact of anesthesia on transcranial electric motor evoked potential monitoring during spine surgery: a review of the literature. neurorsurg focus. 2009;27(4):1-4. pmid:19795956. 4 alviar mj, hale t, dungca m. pharmacologic interventions for treating phantom limb pain. 2011. the cochrane library. http://onlinelibrary.wiley.com./doi/10.1002/146 551858.cd006380.pub2/full. accessed january 28, 2012. 5 sigtermans mj, van hilten jj, bauer mcr, et al. ketamine produces effective and long-term pain relief in patients with complex regional pain syndrome type 1. pain. 2009;145(3):304-311. pmid:19604642. 6 loftus rw, yeager mp, clark ja, et al. intraoperative ketamine reduces perioperative opiate consumption in opiate-dependent patients with chronic back pain undergoing back surgery. anesthesiology. 2010;113(3):639646. pmid: 20693876. 7 dao j. learning to accept, and master, a $10,000 mechanical arm. the new york times. november 27, 2012:a1. anesthesia ejournal volume 3 issue 1 2015 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 the laryngeal mask airway: is it safe for pediatric adenotonsillectomy? jo reid, crna, msna paul n. austin, crna, phd** ricardo e. rodriguez, phd*** source of grant or financial support: none disclosure: the author has no commercial associations that might pose a conflict of interest in connection with this work. abstract tonsillectomy with or without adenoidectomy (t&a) is one of the most common pediatric surgical procedures performed in the united states. traditionally, an endotracheal tube has been used to secure the airway in these cases. however, the laryngeal mask airway (lma) is also used for pediatric t&as. this review explores the question, in pediatric patients undergoing tonsillectomy with or without adenoidectomy, does the laryngeal mask airway compared with the endotracheal tube provide a safe and effective means of airway management? while all evidence sources concluded that it was possible to use an lma for pediatric t&a, not all investigators fully supported its use in this setting. the authors of 6 of the 7 evidence sources determined that the lma was an overall safe and viable alternative for this procedure, but one of the randomized controlled trials identified issues with kinking and visualization and called for further study. future investigation should compare different types of laryngeal mask airways to determine superiority in terms of surgical access, visualization, and reduced displacement or kinking with insertion of the mouth gag. keywords: adenotonsillectomy, anesthesia, laryngeal mask airway, pediatrics, tonsillectomy. introduction about 500,000 tonsillectomies with or without adenoidectomy are performed in children younger than 15 years each year in the united states.1 for the anesthesia provider, a secure and protected airway is one of the primary goals during this procedure due to sharing the airway with the surgeon. traditionally, the endotracheal tube (ett) has been the airway of choice for pediatric patients undergoing adenotonsillectomy (t&a), but it is not without potential complications. these include, but are not limited to, trauma to the lips, teeth, gums, and larynx; bronchospasm; and laryngospasm. laryngospasm, occurring in 4% to 14% of pediatric patients undergoing general anesthesia, is a potentially life-threatening complication that can occur during induction or emergence from anesthesia.2 the laryngeal mask airway (lma) was developed by dr. archie brain, introduced to the practice of anesthesia in 1988, and approved by the u.s. food and drug administration in 1991.3 its popularity within the anesthesia community continues to grow, and its use has been reported for otolaryngoscopy procedures.4 this paper reviews the evidence comparing the efficacy of the lma to the ett in pediatric patients undergoing tonsillectomy or t&a. history and review of the literature history. tonsillectomy with or without adenoidectomy (collectively referred to as “t&a”) is a common pediatric surgical procedure in the united states.1 reasons that children are scheduled for a t&a are chronic or recurrent tonsillitis, obstructive sleep apnea, and obstructive tonsillar hyperplasia. upper respiratory infections are also a common comorbidity in this patient population. for these reasons, patients who present for this surgical procedure are at increased risk for airway complications.1 the lma is a supraglottic airway device inserted into the patient’s hypopharynx, where it rests above the laryngeal inlet. advantages to using the lma include ease of insertion, decreased respiratory stimulation, decreased risk of trauma (particularly to the larynx), and avoidance of the use of neuromuscular blocking agents.2 the use of the lma for t&as is not without potential complications, with 2 of the most common being mechanical obstruction with placement of the mouth gag by the surgeon and surgical access. the surgeon’s training and preference and the experience level of the anesthesia provider are important factors that should not be over-looked. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 1 2015 a review of the literature examining patient outcomes and satisfaction of all involved may lead to a change in care for this patient population. the pico question the key to any successful search for evidence begins with the development of a well-focused clinical question. the patient, intervention, comparison, and outcome (pico) design helps facilitate this search for evidence.5 the pico question guiding the literature search was “in pediatric patients undergoing t&a (patient), does the lma (intervention) compared with an ett (comparison) provide a safe and effective means of airway management (outcome)?” search strategy the search for evidence was conducted using the following databases: pubmed (1990-2014), national guideline clearinghouse (1990-2014), and the cochrane library (19902014). keywords and keyword strings used for the search included “pediatric(s),” “laryngeal mask airway,” “lma,” “endotracheal tube,” “t&a,” “ tonsillectomy,” “adenoidectomy,” “adenotonsillectomy,” and “complications,” alone or in combination. the search for evidence was limited to systematic reviews with and without meta analysis, interventional studies, and observational studies. english language peer reviewed journal articles and evidence based clinical practice guidelines from professional organizations and governmental websites comparing the use of lma with ett for pediatric t&a were included. evidence comparing the use of lmas with etts in adults was excluded. the title of each evidence source was reviewed to determine if inclusion criteria were met. the abstract was reviewed and the full text examined. the reference lists from included articles were searched for additional evidence. surgical colleagues of the one of the authors ( jr) were interviewed for potential sources of evidence. any sources received from these experts went through the same steps to determine if inclusion criteria were met. records were maintained for these sources after each level of review. studies included in an appraised systematic review were not appraised. critical appraisal of the literature seven citations4,6-11 met the search criteria (figure 1). critical appraisal of the evidence followed the methods outlined by melnyk and fineout-overholt.12 table 1 contains the evaluations of five randomized controlled trials (rcts),4,6-9 a retrospective review11 comparing the use of lma to the ett for pediatric t&a, and a prospective study10 examining the safety of the lma for pediatric t&a. authors of all the rcts4,6-9 randomly assigned subjects undergoing t&a using lma or an ett. all but 1 trial6 used power analysis to determine sample size. due to the nature of the trials, blinding of the anesthesia provider and surgeon was not possible. only 1 trial6 out of the 5 rcts in this literature review had the advantage of being a blinded study. postanesthesia providers and the phone surveyor who called the subjects 24 hours after surgery were blinded. this was also the only study that lost a subject to follow up, because phone surveyors were unable to reach that subject by phone. no mention of the data collectors’ level of training was provided for any rct.4,6-9 there were no statistically significant demographic differences between the lma group and the ett group in any rct.4,6-9 the only difference between the experimental and control group in each of these trials was the device used for airway management. all rcts4,6-9 sought to determine the suitability of the lma for t&a. three rcts4,6,7 involved anesthesia providers who had undergone additional pediatric training, and the other 28,9 did not mention extra pediatric training. in an rct,9 4 anesthetists participated and were experienced in pediatric intubation, but they had no experience with the lma for t&as until the start of the study. the anesthesia providers involved in another rct8 spent a year before the start of the trial familiarizing anesthesia providers with the reinforced lma. the setting of the nonrandomized prospective study10 was an office-based otolaryngology practice in norway. data were collected from 1,126 consecutive patients over a 5-year period. the authors examined whether the lma was safe for t&a and if this procedure could be safely carried out in an office based practice. subjects scheduled for adenoidectomy were 2 years old and older, while subjects scheduled for tonsillectomy were 3 years and older. the same surgical team was used for all procedures and consisted of a surgeon, anesthesiologist, nurse anesthetist, and nurse assistant. a reusable lma was chosen for all patients. data collection methods were not described in detail. all tonsillectomy patients were called 24 hours after surgery to identify problems such as sore throat. lalwani et al11 reported the findings of a retrospective review conducted at a children’s hospital in oregon. data were collected from the electronic health records of more than 1,000 subjects who underwent t&a from january 2002 to december 2006. three pediatric otolaryngology surgeons and 15 pediatric anesthesiologists were involved in the cases, and subjects were grouped according to method of airway control. discussion of state of the art the authors of 44,6,8,9 of the 54,6-9 rcts concluded that the lma was a viable and overall safe alternative to the ett for pediatric t&a. however, 1 group4 indicated that visualization and kinking issues should be addressed. the rct by ranieri et al7 concluded that the ett was preferred over the lma for safety. in an rct, sierpina et al6 used a reinforced lma for pediatric t&a. thirty-six variables were analyzed, including safety, comfort, complications, and postoperative problems. less coughing and gagging were reported with the lma, and no statistically significant differences in rate of respiratory complications were reported between the 2 groups. none of the subjects in the lma group required conversion to an ett, but all anesthetics and surgical procedures were performed by providers with specialty training in the field of pediatrics. this may affect the results in settings where specialty trained providers are not available. there was no significant difference in operative times between the 2 groups. while the authors did not state that the lma was as safe as the ett, it is their airway of choice in healthy, nonobese children without severe obstructive sleep apnea presenting for t&a.6 anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 1 2015 the remaining 3 studies4,8,9 also determined that the lma was an effective alternative for airway management for pediatric t&a. the anesthesia providers involved in 1 rct4 had received extra anesthesia training. one of the studies4 used flexible lmas, and 28,9 used reinforced lmas. in the study4 examining use of the flexible lma, there was kinking of the lma in 15 subjects with insertion of the mouth gag in the study using the flexible lma, with 8 requiring conversion to an ett. two additional subjects required conversion to an ett due to poor visualization. there were no significant differences in the postoperative rate of laryngospasm or desaturation between the 2 groups. both rcts8,9 using a reinforced lma described 5 subjects requiring conversion to an ett. doksrød et al9 reported that all 5 conversions were due to poor surgical access. in the other rct,8 4 of the conversions were due to transient drops in oxygen saturation, and 1 was due to an unresolved leak with positive pressure ventilation in a subject with very large tonsils. the authors8 pointed out that all 5 conversions occurred in the first 15 cases of the study. after it was discovered that a deeper plane of anesthesia was necessary before insertion of the lma, no other subjects required conversion to an ett. the occurrence of postoperative laryngospasm and desaturation were the same between the ett and lma groups.8 the investigators7 of the fifth rct analyzed concluded that the disposable lma could be used, but the ett was preferred for safety. they pointed out a greater incidence of desaturation due to unresolved leaks in the lma group after establishment of the surgical field. eight subjects in the lma group developed a leak after hyperextension of the neck, which was unresolved after repositioning the lma. one subject in the lma group regurgitated and required conversion to an ett. there were no significant differences in the operative time or rate of laryngospasm between the 2 groups. the prospective study10 provided a lower quality of evidence. a reusable lma was used for all subjects unless a complication arose. six subjects required repositioning of the lma before the start of surgery, and conversion to ett was required in 7 cases. it was not reported if repositioning was needed before or after insertion of the mouth gag. six of the subjects who required conversion to an ett had an air leak around the lma, which may have been the result of using a flexible, reusable lma. one subject required intubation at the end of surgery due to atelectasis from a bronchial plug. there was no discussion of how the sample size was determined or why a flexible lma was chosen. neither was there any discussion of the age of the subjects who required conversion to an ett. the retrospective review11 also provided a lower quality of evidence. there were no statistically significant demographic differences among the lma success, lma failure, and ett groups. the investigators identified predictors of failure and complications with the lma and concluded that an lma was an alternative technique for t&a. of 1,162 subjects (lma 37.6%, flexible lma 2.7%, ett 59.7% ), the lma failed 33 times, with almost 80% of the failures occurring during induction or insertion of the mouth gag. age, type of surgery, mode of ventilation, and surgeon were associated with lma failure. it is important to note that 1 surgeon and adenoidectomy alone had a statistically significant lower rate of failure, whereas the younger age of the subject and the use of controlled ventilation were associated with a statistically significant higher rate of failure. self-report bias and lack of randomization were limitations of this retrospective review. it was impossible to determine if the experience level of the anesthesiologist affected outcomes, due to the low number of subjects per anesthesia provider. summary while all evidence4,6-11 showed that it is possible to use an lma for pediatric t&a, all investigators did not fully support its use in this setting. the authors of 6 of the evidence sources4,6,8,9,-11 determined that the lma was an overall safe and viable alternative for pediatric t&a, but 1 group4 indicated that the issues with kinking and visualization needed further study. only 1 source7 concluded that the ett was preferred over the disposable lma for safety. the retrospective review11 indicated that the lma is an alternative to an ett for t&a. the reinforced lma was used in 3 of the trials6,8,9 supporting the use of the lma, and the flexible lma was used in the 2 trials4,7 reporting issues with kinking and other complications. although the investigators of a large study10 successfully used a non-reinforced lma, they concluded that the type of lma used could have been responsible for its failure. age may also play a role in failure of the lma. lalwani et al11 reported that, as age decreased, the rate of failure increased. it should be noted that the flexible lma was used in all subjects in this review. anesthesia providers must choose the airway management method in conjunction with the surgeon and consider the risks and benefits of each device. to increase safety, it is important that the anesthesia provider has experience using the lma in the pediatric population. the cooperation of the surgeon is also necessary, because adjustment of the lma or mouth gag may be necessary. future research should compare the reinforced lma with the flexible lma to determine if it provides better surgical access, visualization, and reduced kinking or displacement (or both) on insertion of the mouth gag. because a benefit of using the lma is decreased respiratory stimulation, the inclusion of subjects with asthma or recent upper respiratory infections should also be considered. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 1 2015 references 1. tonsillectomy and/or adenoidectomy in children: preoperative and intraoperative care. uptodate. available at: http://www. uptodate.com/contents/tonsillectomy-and-or-adenoidectomy-in-children-preoperative-and-intraoperative-care. accessed april 19, 2015. 2. flick rp, wilder rt, pieper sf, et al. risk factors for laryngospasm in children during general anesthesia. paediatr anaesth. 2008;18(4):289-296. 3. hernandez mr, klock pa jr, ovassapian a. evolution of the extraglottic airway: a review of its history, applications, and practical tips for success. anesth analg. 2012;114(2):349-368. 4. peng a, dodson km, thacker lr, kierce j, shapiro j, baldassari cm. use of laryngeal mask airway in pediatric adenotonsillectomy. arch otolaryngol head neck surg. 2011;137(1):42-46. 5. richardson ws, wilson mc, nishikawa j, hayward rs. the well-built clinical question: a key to evidence-based practices. acp j club. 1995;123(3):a12-a13. 6. sierpina di, chaudhary h, walner dl, et al. laryngeal mask airway versus endotracheal tube in pediatric adenotonsillectomy. laryngoscope. 2012;122(2):429-435. 7. ranieri d jr., neubauer ag, ranieri dm, do nascimento p jr. the use of disposable laryngeal mask airway for adenotonsillectomies. rev bras anestesiol. 2012;62(6):788-797. 8. doksrød s, løfgren b, nordhammer a, svendsen mv, gisselsson l, raeder j. reinforced laryngeal mask airway compared with endotracheal tube for adenotonsillectomies. eur j anaesthesiol. 2010;27(11):941-946. 9. webster ac, morley-foster pk, dain s, et al. anaesthesia for adenotonsillectomy: a comparison between tracheal intubation and the armoured laryngeal mask airway. can j anaesth. 1993;40(12):1171-1177. 10. gravningsbråten r, nicklasson b, raeder j. safety of laryngeal mask airway and short-stay practice in office-based adenotonsillectomy. acta anaesthesiol scand. 2009;53(2):218-222. 11. lalwani k, richins s, aliason i, milczuk h, fu r. the laryngeal mask airway for pediatric adenotonsillectomy: predictors of failure and complications. int j pediatr otorhino-laryngol. 2013;77(1):25-28. 12. melnyk bm, fineout-overholt e. evidence-based practice in nursing and healthcare: a guide to best practice. 2nd ed. philadelphia: wolters kluwer, lippincott williams & wilkins. 2011:3-24. texas wesleyan university graduate programs of nurse anesthesia, doctorate of nurse anesthesia program fort worth, tx 3081 linksland road mount pleasant, sc 29466 voice phone number: 843-810-9910 email: jreid4@hotmail.com **professor, texas wesleyan university, graduate programs of nurse anesthesia 14311 harvest moon rd boyds, md 20841 301-728-5435 paustin@txwes.edu ***professor, texas wesleyan university, graduate programs of nurse anesthesia 1201 wesleyan st fort worth, tx 76106 817-531-4256 rrodriguez@txwes.edu short biographical statement jo reid, crna, dnap, is the chief cardiac nurse anesthetist at trident medical center in charleston, sc. the author was a student in the doctorate of nurse anesthesia program at texas wesleyan university at the time this article was written. paul n. austin, crna, phd, is a professor, doctorate of nurse anesthesia practice program at texas wesleyan university. ricardo e. rodriguez, phd, is a professor of pharmacology, graduate programs of nurse anesthesia at texas wesleyan university. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 1 2015 figure 1 —evidence comparing the use of the laryngeal mask airway to the endotracheal tube for pediatric adenotonsillectomy table 1 evidence source type and level of evidencea sample size lma type outcome comments webster et al9 (1993) randomized clinical trial level ii 109 reinforced lma inserted faster than ett in 91% of cases (p<.001) hr and map less (p<.001) in lma group sample size determined using a power analysis 5 subjects were converted to ett early in the study when providers were unfamiliar with the lma for t&a gravningsbråten et al10 (2009) prospective study level iii 1,126 reusable conversion from lma to ett occurred in 6 subjects (0.5%) due to leakage with ventilation 1 subject (0.1%) required intubation with lavage and suction due to a bronchial plug at the end of the operation the same team performed all cases no randomization; the lma was the first choice for airway management 12 sources were found using the initial key word string “pediatric and laryngeal mask airway and tonsillectomy” 6 sources were found when the word “adenoidectomy” was substituted for “tonsillectomy” 3 sources were found when “adenotonsillectomy” was substituted for “adenoidectomy” 10 sources met the inclusion criteria based on title 8 sources met the inclusion criteria based on the abstract 7 sources met the inclusion criteria based on the full text the results of these searches were found in the results of the initial keyword string anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 1 2015 doksrød et al8 (2010) randomized single center trial level ii 134 reinforced 5 lma cases converted to ett due to inferior surgical access significantly less pain in lma group (p=.015) during first 4 hours randomization based on computer generated program case completion rate with lma was 92.8% faces/pain scale was used, and subjects/ parents were instructed in its use sample size based on 80% statistical power and a level of 5% peng et al4 (2011) randomized clinical trial level ii 134 flexible no statistically significant difference in rate of laryngospasm or adverse perioperative events no statistically significant difference in total anesthesia, surgical, or recovery times sample size determined using a power analysis data from 12 subjects in the lma added to ett, so did not follow intention to treat sierpina et al6 (2012) randomized clinical trial level ii 117 flexible less coughing and gagging during anesthesia for all surgeries with lma but no difference between the ett tonsillectomies recovery nurses and phone surveyors were blinded no discussion of how sample size was determined ranieri et al7 (2012) randomized clinical trial level ii 204 disposable no significant difference in respiratory complications 4 subjects converted to ett greater incidence of sao2 decreased in lma after operative field established (p=<.001) single surgical and anesthesia team specific definitions for each respiratory complication were provided lma repositioned; if leak still present, converted to ett to avoid hypoxemia or other complications limitations due to nature of study include lack of randomization and possible self-report bias lalwani et al11 (2013) retrospective review level iv 1,199 flexible (2.7%, of subjects) lma type not described (37.6% of sub-jects) ett (59.6% overall failure rate of the lma was 6.8% adenoidectomy alone had lower odds of failure compared with tonsillectomy or t&a (or 0.28, 95% ci 0.15-0.52) one surgeon associated with decreased odds of failure (or 0.46, 95% ci 0.45-0.48) younger subjects associated with increased odds of failure (or 1.05 for each year decrease in age, 95% ci 1.03-1.07) controlled ventilation associated with increased odds of failure (or 7.17, 95% ci 4.99-10.32) unable to compare outcomes between anesthesia providers due to inadequate number of cases per provider unable to compare outcomes between anesthesia providers due to inadequate number of cases per provider afrom melnyk and fineout-overholt12 ci, confidence interval; ett, endotracheal tube; hr, heart rate; lma, laryngeal mask airway; map, mean arterial pressure; or, odds ratio; t&a, adenotonsillectomy; sao2, oxygen saturation of hemoglobin in arterial blood. anesthesia ejournal volume 4 issue 1 2016 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 page 50 efficacy of ondansetron as a prophylactic anti-hypotensive pharmacologic intervention among obese parturients undergoing spinal anesthesia for cesarean delivery melissa dawn hudson1,msna, dnp, crna, aprn neva l crogan1, ph.d., arnp, gnp-bc, fngna, faan edward j. bilsky2, ph.d affiliation: 1 gonzaga university 2 university of new england funding/conflict of interest disclosure: none keywords: ondansetron; obesity; pregnancy; spinal anesthesia; hypotension; cesarean delivery introduction background recognized as a pandemic nutritional disorder by the world health organization,1 obesity has become one of the most critical global health issues. obesity in the united states has been on the rise for more than 30 years despite the objectives of healthy people 2000 through healthy people 2020. in fact, prevalence estimates by the centers for disease control and prevention (cdc) indicate that more than one-third of the population of the united states is overweight (body mass index [bmi] of 25–29.9), while more than one-fourth of the population is obese (bmi of 30–99.8).2 in 2012, washington state reported that 35.4% of its residents were overweight and 26.8% of its residents were obese.3 among those surveyed in the 2011-2012 national health and nutrition examination survey, 34.9% of women were considered obese.4 in alignment with this trend in population health is the statement by the cdc that “in the united states, obesity during pregnancy is common and it increases obstetrical risks.”5 as obesity has increased in both incidence and prevalence in the general population, the rate of obesity in the obstetric population has correspondingly grown. among the greatest contributing factors to anesthetic risk in pregnancy are the sequelae resultant from obesity.5,6 increased anesthetic risk is a result of the multisystemic physiologic changes associated with pregnancy. the most significant contributors to maternal mortality are the elevated physiologic demands on the respiratory and cardiovascular systems. associated with serious morbidity, obesity in the parturient further increases anesthetic risk as well as the incidence of instrumental and cesarean deliveries.5 abstract background and purpose: obesity is a risk factor for hypotension after spinal anesthesia among parturients undergoing cesarean delivery. although researchers have demonstrated that prophylactic administration of ondansetron is efficacious in attenuating maternal hypotension following spinal anesthesia, no studies have examined the efficacy of prophylactic ondansetron in the high-risk population of obese parturients. the primary objective of this study was to assess the efficacy of the novel application of ondansetron as a prophylactic anti-hypotensive pharmacologic intervention among obese parturients to facilitate practice recommendations for reducing maternal-fetal risk associated with the administration of spinal anesthesia for cesarean delivery. methods: retrospective chart analyses of 46 patients with a body mass index > 30 were conducted between august 1, 2014, and may 10, 2015, to determine whether the intravenous administration of 4 mg ondansetron before the induction of spinal anesthesia reduced the frequency of vasopressor administration during cesarean delivery. results: the incidence of vasopressor administration among patients who received prophylactic ondansetron was 35.7%, whereas 46.9% of patients who did not receive prophylactic ondansetron required vasopressor administration (x2 = 0.144, df = 1, p = 0.704). conclusions: obese parturients undergoing spinal anesthesia for cesarean delivery demonstrated improvements in hemodynamic stability when prophylactically treated with ondansetron. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 51 for the obese parturient, the subsequent necessitation of the administration of anesthesia additionally burdens the cardiovascular and respiratory systems. tan and sia stated, “the engagement of the obstetrical anesthetist in the management of this group of high-risk patients should be performed antenatally so that an appropriate management strategy can be planned in advance to prevent an adverse outcome.”7 among the most common adverse outcomes observed in obese parturients undergoing spinal anesthesia for cesarean delivery is hypotension.8 the sequelae resultant from hypotension among parturients are particularly worrisome as they include both maternal and fetal effects and occur at an incidence of 20% to 100%.8 serious maternal-fetal consequences secondary to hypotension include fetal hypoxia resultant from utero-placental insufficiency and an increased incidence of maternal nausea and vomiting secondary to hypoperfusion of the chemoreceptor trigger zone and vomiting centers within the medulla.9 therefore, nani and torres concluded in their study correlating the bmi of pregnant women with the development of hypotension after spinal anesthesia for cesarean delivery that anesthetic techniques should be improved to reduce the consequences of spinal-induced hypotension in both pregnant women and their fetuses.8 prophylactic utilization of intravenous ondansetron has been identified as a mechanism by which to decrease anesthetic risk among parturients undergoing spinal anesthesia for cesarean delivery via the abatement of the bezold-jarisch reflex (bjr), with resultant improvements in hemodynamic stability including a decrease in the incidence of hypotension.10,11 through increased vagal tone, the bjr has been identified as a contributing factor to maternal hypotension following induction of spinal anesthesia. characterized by bradycardia and worsening hypotension, the reflex is initiated by chemoreceptors in the left ventricle, identified as 5-hydroxytryptamine-3 (5ht3) receptors, in response to spinal anesthetic-induced systemic vasodilation and resultant relative hypovolemia.12 attenuation of the bjr may therefore decrease the incidence of severe refractory hypotension in obese parturients undergoing spinal anesthesia for cesarean delivery. as a result, reduction of anesthetic risk in this specific vulnerable population of obese parturients may be feasible.10 significance many are affected by and invested in the health and well-being of pregnant patients with bmi > 30. as obesity is passed down from mother to child, the obesity epidemic continues to become more prevalent and more profound despite national efforts to address the issue. stakeholders therefore include community health care systems, agencies, and providers who confront unique challenges associated with caring for obese parturients. anesthetists are directly affected by the obesity pandemic given that elevated bmi is associated with increased perioperative risk. the cdc5 drew on the work of chu et al6 in finding that “obesity during pregnancy is associated with increased use of health care and physician services, and longer hospital stays for delivery.” cesarean delivery rates are also higher at 45.2% for extremely obese women versus 21.3% for nonobese women.1 delivery via cesarean incurs greater anesthetic risk and is associated with higher medical costs. in fact, the estimated annual medical cost of obesity in the united states was calculated to be $147 billion in 2008.3 compared with the nonobese population, medical costs for obese patients were $1429 higher per person.13 literature review ondansetron, when administered 5 minutes before a subarachnoid block, has been identified as an efficacious intervention to reduce the incidence of spinal anesthesiaassociated hypotension for cesarean delivery. sahoo et al10 conducted a randomized controlled trial (rct) that was later expanded upon by wang et al.14 the researchers demonstrated that 4 mg of ondansetron given intravenously 5 minutes before a subarachnoid block was effective in reducing the incidence of spinal anesthesia-associated hypotension during cesarean delivery. the researchers’ purpose was to clearly define the effect of ondansetron on the hemodynamic response following spinal anesthesia for cesarean delivery, based on the physiologic effects of 5ht3 antagonists on the bjr. the bjr results in profound hypotension and bradycardia as a result of increased vagal tone due to stimulation of chemoreceptors in the left ventricle. a sample size of 52 parturients was randomized to 2 groups. one group received intravenous ondansetron; the other received normal saline before spinal anesthetic for cesarean delivery. vital signs and vasopressor administration were recorded and quantified as outcome measures. the results revealed fewer hypotensive episodes and a resultant decrease in vasopressor administration in the ondansetron group (p < 0.001). of the 26 parturients in the ondansetron group, 2 required vasopressor administration (7.69%). of the 26 parturients in the saline group, 11 required vasopressor administration (42.31%). the absolute difference was a 34.62% decrease in vasopressor administration when ondansetron was administered prophylactically.10 compared with the results of the current study, a similar decrease in the frequency of vasopressor administration was observed in both the obese and the nonobese patient populations following initial doses of 4 mg ondansetron administered before spinal anesthesia. wang et al conducted a double-blind rct that included 66 parturients scheduled for elective cesarean delivery. five minutes before receiving spinal anesthesia, patients received ondansetron or saline. in addition to maternal hemodynamics, wang et al analyzed umbilical cord blood samples after delivery to determine the incidence of fetal acidosis. study findings included increased fetal ph as well as decreased incidence of maternal hypotension and nausea among those prophylactically treated with ondansetron.14 chu and colleagues reported in the new england journal of medicine that higher bmi was related to increased rates of cesarean delivery and obesity-related high-risk conditions.6 it is consequently more likely that an obese parturient will require the intervention of an anesthetist during labor and delivery as a result of the increased incidence of cesarean or instrumental delivery among such patients. furthermore, owing to the increased incidence of obesity-related high-risk conditions during pregnancy, anesthetic risk is compounded. according to cooper and mcclure, complications directly related to anesthesia were deemed responsible for the deaths of 6 women in the united kingdom, thereby demonstrating anesthesia as one of the leading causes of death among parturients.15 numerous research studies over recent years have confirmed that obese parturients present even greater anesthetic risk than their nonobese counterparts.8,16-22 nani and torres specifically addressed the incidence of hypotension after the administration of spinal anesthesia as it relates to bmi. the sample size for anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 52 normal-weight patients, as defined by a bmi less than 25, was 49. the sample size for the overweight group, as defined by a bmi greater than or equal to 25, was 51. the results reflected fewer episodes of hypotension in the non-overweight group. confidence intervals of 5.89 ± 0.53 episodes versus 7.80 ± 0.66 episodes, with a p value of 0.027, were reported, compared with 5.36 to 6.42 episodes of hypotension following spinal anesthesia for cesarean in patients with bmi < 25. the p value was determined to be 0.027.8 risk versus benefit researchers have demonstrated that anesthetic risk associated with spinal anesthesia-related hypotension among parturients undergoing cesarean delivery may be attenuated with the prophylactic administration of ondansetron.10,14 obese parturients undergoing spinal anesthesia for cesarean delivery have a higher incidence of severe refractory hypotension than do their nonobese counterparts.8-22 hence, the population that may benefit most from the application of prophylactic antihypotensive ondansetron administration is obese parturients. however, incorporation of such evidence into clinical practice by anesthesia providers has been slow and inconsistent. this may be due, in part, to the fact that the findings of current literature support the need for further evaluation of evidence-based practice recommendations for the specific population of highrisk obese parturients undergoing spinal anesthesia for cesarean delivery. ondansetron, a widely used anti-emetic and serotonin antagonist, has been safely used to blunt the bjr, resulting in less bradycardia and hypotension first in animals and later in humans undergoing a subarachnoid block.10,14 ondansetron is a selective serotonin antagonist specific to the 5ht3 receptor. although initially designed to target 5ht3 receptors in the chemoreceptor trigger zone responsible for nausea and vomiting, the novel administration of ondansetron for the prevention of hypotension secondary to blockade of 5ht3 receptors in the left ventricle has shown potential for clinical utility in the prevention of hypotension and bradycardia associated with the bjr.10 ondansetron is a drug commonly administered in hospital operating rooms throughout the united states for the prevention of postoperative nausea and vomiting. as such, it has a wellestablished safety record provided it is given within the recommended dose of 4 mg intravenous for adult patients and 0.1-0.15 mg/kg for pediatric patients. the primary side effects associated with ondansetron include asthenia, constipation, diarrhea, headache, and somnolence.11 as with all pharmacologic interventions, judicious administration is recommended. methods ethical concerns institutional review board (irb) exemption was obtained through gonzaga university. because the scholarly project was a retrospective, observational chart review, no patient informed consent was deemed necessary. site support for the project was obtained by the department of anesthesia at our community hospital, the hospital administrator, and the director of health information. setting as of the last census data, the county studied was tied for the county with the second highest prevalence of obesity in washington state. the city that was the focus of the study is rural, with a population of less than 8000, within this county. the hispanic population of the city represents 61.4% of the total population, compared with 11.9% in washington state. in addition, persons living below the poverty level in the city account for 22.9% of the population, compared with 13.4% statewide.3 of those undergoing a cesarean delivery at our community hospital in 2014 (n = 117), the majority, approximately 97%, were hispanic. hispanic ethnicity and higher rates of poverty are associated with higher rates of peripartum obesity.23 therefore, a retrospective chart review of obese parturients who necessitated spinal anesthesia for cesarean delivery was productive and efficacious in the assessment of ondansetron administration for the prevention of intraoperative hypotension at our community hospital. as a result, this study provided useful clinical information regarding the reduction of anesthetic risk in this specific vulnerable population6 and will facilitate evidence-based practice recommendations. intervention by use of a retrospective design, we analyzed medical records from parturients with a bmi greater than or equal to 30 who were admitted to the community hospital between august 1, 2014, and may 10, 2015, to determine whether the intravenous administration of 4 mg ondansetron prior to the induction of spinal anesthesia reduced the frequency of administration of vasopressors during cesarean delivery. utilization of prophylactic ondansetron was based on current literature and had only been implemented into clinical practice at this institution as of august 2014. therefore, august 1, 2014, was established as the start date for all data collection. numerous data points were included in the chart review. patient information included bmi, maternal age, gestational age, and ethnicity. interventional information collected included time of initiation of spinal anesthetic, time of prophylactic ondansetron administration (if applicable), dose of 0.75% spinal bupivacaine with dextrose (milliliters) administered, dose of spinal morphine sulfate (milligrams) administered, time of initial vasopressor administration (if applicable), total ephedrine dose administered (if applicable), and total phenylephrine dose administered (if applicable). the same data were also collected and analyzed on the nonobese population for purposes of comparison. data were analyzed from the charts of 3 different anesthesia providers. data analysis descriptive analyses were conducted by using excel software for windows (microsoft corp) to synthesize and describe patient characteristics (age, bmi, ethnicity, and gestation) as well as frequency, mean, median, and mode of all data. a chi-square test was used to analyze whether the observed difference in the vasopressor requirements of the group of patients who received ondansetron and the group of patients who did not receive ondansetron was significant. an independent samples t-test was utilized to determine the statistical significance of the observed decrease in ephedrine dosing among patients who received prophylactic ondansetron versus those who did not. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 53 hypotension was considered significant and counted among the incidents included in the statistical analysis if it necessitated treatment as evidenced by administration of phenylephrine or ephedrine as documented on the anesthetic record. the total dose of vasopressor administration was recorded for each patient and subsequently compared between obese patients who did and did not receive ondansetron before the induction of spinal anesthesia. results retrospective chart analysis of 46 patients with bmi > 30 at our community hospital between august 1, 2014, and may 10, 2015, revealed an 11.175% decrease in vasopressor administration among the 14 patients who received 4 mg iv ondansetron 5 minutes before spinal anesthesia for cesarean delivery compared with the 32 patients who were not treated with prophylactic ondansetron (figure 1). although not included in the study of obese parturients, data were collected from nonobese patients for the purposes of comparison. among the 24 patients excluded from the chart review because of having a bmi < 30, 7 patients received prophylactic ondansetron. of the nonobese patients who received prophylactic ondansetron, none required vasopressor administration intraoperatively, representing a substantial improvement in maternal hemodynamics. of the 17 nonobese patients who did not receive prophylactic ondansetron, 47% required intraoperative vasopressor administration. however, this difference was not significant (x2 = 0.144, df = 1, p = 0.704) (table 1). figure 1. ondansetron administration versus vasopressor administration. of 46 patients, 32 were not treated and 14 were treated with prophylactic ondansetron. the chart visually demonstrates the 11.175% decrease in the rate of vasopressor administration with the prophylactic administration of ondansetron. case processing summary cases valid missing total n percent n percent n percent ondansetron 1=yes; 0=no * vasopressor 1= yes; 0=no 46 100.0% 0 0.0% 46 100.0% ondansetron 1=yes; 0=no * vasopressor 1= yes; 0=no cross tabulation vasopressor 1= yes; 0=no no vasopressor yes vasopressor total count 17 15 32 no ondansetron expected count 18.1 13.9 32.0 count 9 5 14 ondansetron 1=yes; 0=no yes ondansetron expected count 7.9 6.1 14.0 count 26 20 46 total expected count 26.0 20.0 46.0 chi-square tests value df asymp. sig. (2-sided) exact sig. (2-sided) exact sig. (1-sided) pearson chi-square .494a 1 .482 continuity correctionb .144 1 .704 likelihood ratio .499 1 .480 fisher's exact test .535 .355 linear-by-linear association .483 1 .487 n of valid cases 46 a. 0 cells (.0%) have expected count less than 5. the minimum expected count is 6.09. b. computed only for a 2x2 table anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 54 only 3 obese parturients who received ondansetron required ephedrine administration, with a mean dose of 10 mg administered. of the obese parturients not prophylactically treated with ondansetron, 14 required ephedrine administration, with a mean dose of 18.57 mg administered. similarly, only 2 obese parturients who received prophylactic ondansetron required phenylephrine, with a mean dose of 0.1 mg administered. of the obese parturients not prophylactically treated with ondansetron, 1 required phenylephrine administration, with a dose of 0.05 mg administered. an independent samples t-test revealed that there was not a significant mean difference in vasopressor administration dosage between those who received ondansetron (m = 10, sd = 5) and those who did not receive ondansetron (m = 18.57, sd = 7.45; t(15) = 1.35, p > 0.05) (table 2). overall results showed a reduced pattern of vasopressor administration among obese women who received 4 mg iv ondansetron 5 minutes before receiving spinal anesthesia. however, when compared with women who did not receive ondansetron administration, the frequency of vasopressor administration did not significantly differ between the groups. the average bmi for the obese patients included in the study was 36.97, compared with 27.55 for patients excluded from the study for being nonobese. the average maternal age was 30.06 years for the obese group and 29.833 for the nonobese group. the average gestational age was 38 weeks for the obese group, compared with 38.67 weeks for the nonobese group. among the obese group, 39 (84.7%) were hispanic, whereas 5 (10.8%) were white, and 2 (4.3%) were of other ethnicity (figure 2). case processing summary cases valid missing total n percent n percent n percent ondansetron 1=yes; 0=no * vasopressor 1= yes; 0=no 46 100.0% 0 0.0% 46 100.0% ondansetron 1=yes; 0=no * vasopressor 1= yes; 0=no cross tabulation vasopressor 1= yes; 0=no no vasopressor yes vasopressor total count 17 15 32 no ondansetron expected count 18.1 13.9 32.0 count 9 5 14 ondansetron 1=yes; 0=no yes ondansetron expected count 7.9 6.1 14.0 count 26 20 46 total expected count 26.0 20.0 46.0 chi-square tests value df asymp. sig. (2-sided) exact sig. (2-sided) exact sig. (1-sided) pearson chi-square .494a 1 .482 continuity correctionb .144 1 .704 likelihood ratio .499 1 .480 fisher's exact test .535 .355 linear-by-linear association .483 1 .487 n of valid cases 46 a. 0 cells (.0%) have expected count less than 5. the minimum expected count is 6.09. b. computed only for a 2x2 table figure 2. demographic data on ethnicity. pictorial summary of the ethnicity of the 46 patients included in the study. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 55 it is vital to examine the association between ondansetron administration and vasopressor administration in a larger sample of obese women in the future. it is challenging to detect a significant association between ondansetron administration and vasopressor administration in a limited sample size such as that used in the present study.24-26 discussion limitations although the results of the retrospective chart review demonstrated improvements in hemodynamic stability among obese parturients undergoing spinal anesthesia for cesarean delivery, the project was limited by a small sample size and a retrospective design. future research should be conducted via prospective rct with a larger sample size to provide definitive recommendations for practice change. additional limitations of this retrospective chart review included an inability to control for variances in fluid management, including volume of crystalloid or colloid pre-loading. provider preference and threshold for vasopressor administration also impacted the results of the chart review and will be difficult to control in an rct as well. implications for practice the findings from this retrospective analysis, although based on a small sample size, support the recommendation for routine prophylactic administration of 4 mg iv ondansetron 5 min before the administration of spinal anesthesia for cesarean delivery. considerations regarding differences in the apparent efficacy of ondansetron as a prophylactic anti-hypotensive pharmacologic intervention in obese versus nonobese groups are many. obesityrelated physiologic changes include increased aorto-caval compression secondary to increased weight, greater volume of distribution, and elevated preoperative fluid requirements. pharmacologic considerations include weight-based dosing of ondansetron and the addition of colloids to crystalloids to maximize intravascular volume before the administration of spinal anesthesia among obese parturients. summary as a result of this retrospective chart analysis, it has been demonstrated that the novel application of ondansetron as a prophylactic anti-hypotensive agent administered 5 minutes before the induction of spinal anesthesia may improve hemodynamic stability among patients with a bmi > 30 necessitating cesarean delivery. these findings are consistent with current recommendations for the nonobese population based on the extant medical literature. it may be possible to attenuate the maternal-fetal risk associated with the administration of spinal anesthesia in the vulnerable and ever-increasing population of obese parturients if this evidence-based practice is further established in a larger sample size in an rct and with subsequent widespread adoption into anesthetic protocols. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 56 references 1. obesity and overweight. world health organization website. http://www.who.int/mediacentre/factsheets/fs311/en. version current 2012. accessed march 17, 2015. 2. behavioral risk factor surveillance system 2013. centers for disease control and prevention website. http://www.cdc.gov/ brfss/. accessed march 22, 2015. 3. levi j, segal l, st. laurent r, et al. f as in fat: how obesity threatens america’s future. princeton, nj: robert wood johnson foundation; 2012. 4. ogden cl, carroll md, kit bk, et al. prevalence of obesity among adults: united states, 2011-2012. nchs data brief no. 131. http://www.cdc.gov/nchs/data/databriefs/db131.pdf. published october 2013. accessed march 17, 2015. 5. pregnancy complications. centers for disease control and prevention website. http://www.cdc.gov/reproductivehealth/ maternalinfanthealth/pregcomplications.htm#n5. version current 2014. accessed march 11, 2015. 6. chu sy, bachman dj, callaghan wm, et al. association between obesity during pregnancy and increased use of healthcare. n engl j med. 2008;358(14):1444-1453. http://dx.doi.org/10.1056/nejmoa0706786. 7. tan c, sia ac. anesthesia considerations in the obese parturigrava. semin perinatal. 2011;35(6):350–5, 350. 8. nani f, torres m. correlation between the body mass index (bmi) of pregnant women and the development of hypotension after spinal anesthesia for cesarean section. rev bras anest. 2011;61(1):21-30. http://dx.doi.org/10.1016/s00347094(11)70003-4. 9. borgeat a, ekatodramis g, schenker ca. postoperative nausea and vomiting in regional anesthesia. anesthesiology. 2003;98(2):530-547. http://dx.doi.org/10.1097/00000542-200302000-00036. 10. sahoo t, sendasgupta c, goswami a, hazra a. reduction in spinal-induced hypotension with ondansetron in parturients undergoing caesarean section: a double-blind, randomized, placebo-controlled study. int j obstet anesth. 2012;21(1):24-28. http://dx.doi.org/10.1016/j.ijoa.2011.08.002. 11. wang m, zhuo l, wang q, et al. efficacy of prophylactic intravenous ondanestron on the prevention of hypotension during cesarean delivery: a dose-dependent study. int j clin exp med. 2014;7(12):5210-5216. 12. liu ss, mcdonald sb. current issues in spinal anesthesia. anesthesiology. 2001;94(5):888-906. http://dx.doi. org/10.1097/00000542-200105000-00030. 13. adult obesity facts. centers for disease control and prevention website. http://www.cdc.gov/obesity/data/adult.html. accessed march 17, 2015. 14. wang q, zhuo l, shen mk, yu y-y, yu j-j, wang m. ondansetron preloading with crystalloid infusion reduces maternal hypotension during cesarean delivery. am j perinatol. 2014;31(10):913-922. http://dx.doi.org/10.1055/s-0033-1364189. 15. cooper gm, mcclure jh. anaesthesia chapter from saving mothers’ lives; reviewing maternal deaths due to make pregnancy safer. br j anaesth. 2008;100(1):17-22. http://dx.doi.org/10.1093/bja/aem344. 16. butwick a, carvalho b, danial c, riley e. retrospective analysis of anesthetic interventions for obese patients undergoing elective cesarean delivery. j clin anesth. 2010;22(7):519-526. http://dx.doi.org/10.1016/j.jclinane.2010.01.005. 17. edomwonyi np, osaigbovo pe. incidence of obesity in parturients scheduled for caesarean section, intra-operative complications, management and outcome. east afr med j. 2006;83(4):112-119. http://dx.doi.org/10.4314/eamj.v83i4.9425. 18. horikawa y, fukuda h, kawakami t, et al. the effect of obesity on spinal anesthesia for cesarean section. masui. 2001;50(11):1205-1208. 19. johnson d. management of cesarean delivery in the morbidly obese woman. contemp ob gyn. 2012;57(10):57-61. http:// contemporaryobgyn.modernmedicine.com/contemporary-obgyn/news/modernmedicine/modern-medicine-feature-articles/ management-cesarean-delivery 20. rodrigues fr, brandao mj. regional anesthesia for cesarean section in obese pregnant women: a retrospective study. braz j anesthesiol. 2011;61(1):13-20. http://dx.doi.org/10.1016/s0034-7094(11)70002-2. 21. roofthooft e. anesthesia for the morbidly obese parturient. curr opin anesth. 2009;22(3):341-346. http://dx.doi. org/10.1097/aco.0b013e328329a5b8. 22. vricella l, louis j, mercer b, bolden n. anesthesia complications during scheduled cesarean delivery for morbidly obese women. am j obstet gynecol. 2010;203(3):276.e1-276.e5. http://dx.doi.org/10.1016/j.ajog.2010.06.022. 23. us department of health and human services, office of disease prevention & health promotion. healthy people 2020 topics & objectives. http://healthypeople.gov/2020. accessed june 27, 2016. 24. campbell i. chi-squared and fisher-irwin tests of two-by-two tables with small sample recommendations. stat med. 2007;26(19):3661-3675. http://dx.doi.org/10.1002/sim.2832. 25. cochran wg. the 2 test of goodness of t. ann math stat. 1952;23(3):315-345. http://dx.doi.org/10.1214/aoms/1177729380. 26. fisher ra. the logic of inductive inference. j royal stat. 1935;98(1):39-54. http://dx.doi.org/10.2307/2342435 volume 5 no. 3 2017 educated hand publishing llc “the science behind the art” volume 5 no. 3 2017 anesthesia ejournal online issn 2333-2611 page 14 anesthesia related outcomes in patients receiving regional anesthesia for shoulder surgery in a crna-only practice in the rural setting gregory bozimowski dnp, crna1 peter skellenger ms, crna2 affiliation: 1 university of detroit mercy 2 peter skellenger was a student at university of detroit mercy at the time of writing the manuscript. he is now a practicing crna in mi funding/conflict of interest disclosure: the authors have no funding or conflicts of interest to report. introduction as the population in the united states ages and the demands on the healthcare system increase, so too does the pressure to provide superior anesthesia services that include safe, effective, efficient care with improved outcomes, greater patient satisfaction, and lower cost. this is particularly the case in rural areas of the united states, which account for nearly 72 million americans who may have limited access to providers, where the drive to provide high quality care while reducing costs is paramount.1 regional anesthesia (ra) for shoulder surgery is a commonly used technique. the benefits have been studied and are well documented. one commonly used technique is the administration of an interscalene block (isb) to supplement the administration of general anesthesia (ga) in combination with sedation, or even as a sole anesthetic, has gained favor. the avoidance or reduction of the hemodynamic instability and other adverse effects that may occur as a result of ga is one appeal to that practice.2 in addition, regional anesthesia has been shown to provide postoperative pain relief for patients undergoing shoulder procedures. while single shot isb has been shown to provide significant postoperative pain relief, it is of a short duration and is not without adverse effects.3 a review of the literature was conducted to examine the potential benefits of ra as compared to ga for shoulder surgery with a secondary intent to evaluate the presence of data collected in rural settings. abstract the purpose of this retrospective chart review was to characterize the complication rate and outcomes among a group of patients receiving regional anesthesia (ra) undergoing shoulder surgery in the rural setting utilizing a certified registered nurse anesthetist (crna) only model. demographic information was obtained. patients were primarily asa 2 and 3 classifications and were outpatients with a mean age of 52.6 years. the most common preoperative diagnosis was rotator cuff tear. the recorded procedure was most often shoulder arthroscopy. ra was performed on 70 patients (92.1%) with 6 (7.9%) patients receiving no ra. general anesthesia (ga) was administered with ra to 68 (89.5%) patients with the remainder receiving sedation with ra. pain scores as measured by visual analogue scale (vas) reflected effective analgesia. the mean vas score reported on arrival to pacu was 1.27, after one hour 1.69, and 0.38 upon discharge from pacu. postoperative analgesics were required for 26 (34.2%) patients. the incidence of postoperative nausea or vomiting was 6.6% of patients reporting nausea and 2.6% patients experiencing emesis. the mean anesthesia time was 127.3 minutes with mean operating room time of 121.2 minutes. mean time in pacu was 134.6 minutes. the descriptive data attained in the analysis demonstrate ra as a safe and effective supplement to ga administered by crnas in a rural setting. future research is needed specific to crna-only practice models and rural settings and should include controlled randomized trials to evaluate outcomes in groups consisting of ga, ga+ra, ra + sedation and even ra alone in select populations. aej anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 3 2017 page 15 background the electronic based search of the literature review was completed using the following databases: pubmed, cochrane, infotrac, medline, ovid medline, and cinahl. the following subject headings and combinations were used: “interscalene + shoulder surgery”, “regional anesthesia vs. general anesthesia”, “regional anesthesia + shoulder surgery”, “regional anesthesia”, “ambulatory surgery”, “rural anesthesia”, “rural + anesthesia”. the search revealed many articles that compared ra with ga; however, there is a lack of articles with specificity to the rural setting. (see table 1data-extraction) a meta-analysis by abdallah and colleagues4 reviewed randomized and quasi-randomized controlled trials that compared isb to ga and combined techniques. the authors examined studies conducted between 1994 and 2013 and represented 1090 patients over 23 trials. they reported reduced pain at rest and in motion at various intervals postoperatively in patients who received an isb. the analysis also revealed decreased opioid consumption in the first 24 hours and longer time to request opioids in the isb group. other reported benefits of isb included increased patient satisfaction, decreased time of stay in the post anesthesia care unit (pacu) and hospital admission and a lower incidence of postoperative nausea and vomiting (ponv). the authors concluded that isb provided effective analgesia during the first 6 postoperative hours and reduced opioid related side effects. hadzic and colleagues5 conducted a randomized, blinded, prospective study comparing the techniques of isb to ga with respect to the recovery profiles and patient satisfaction in patients having outpatient shoulder surgery. data were collected from a total of 50 patients placed equally into 2 groups consisting of those receiving an isb and those receiving ga. primary outcome measures included: patients eligible for bypass of phase i pacu instead going directly to phase ii, hospital admission rates, and time to discharge. secondary outcome measurements included: reports of moderate/severe pain, treatment of pain, nausea, vomiting, sore throat, ambulation, oral intake, and time to home readiness. the authors reported that more patients receiving isb (76%) were eligible to bypass phase i of pacu than patients receiving ga (16%). no patients receiving isb were admitted to the hospital, while 16% of the ga group was admitted overnight due to intractable pain. time to discharge of isb patients was found to be 2.5 hours less than patients receiving ga. no patients in the isb group reported moderate to severe pain as compared to 80% of those in the ga group. pain score values and analgesic use differences between the two groups were not statistically significant; however, the authors report these findings as “statistically underpowered”. the authors report that patient satisfaction with anesthesia was higher in the isb group with 79% reporting that they would choose the same anesthetic again while 36% of the patients in the ga group stated they would choose ga again. lehmann and colleagues6 conducted a randomized controlled study of 120 subjects that evaluated the use of isb versus ga, or a combined isb + ga for patients undergoing shoulder arthroscopy. the primary outcome variable measured was opioid consumption on the day of surgery with secondary outcomes being post-op monitoring times, anesthesia times, patient satisfaction, and the ability to bypass the recovery room. in addition, subjective outcomes such as perceived pain and nausea were measured. following surgery, the authors found that 27 of 40 subjects receiving isb only were able to bypass the pacu completely and had the shortest monitoring time necessary in the pacu compared to ga or ga + isb. on the day of surgery, opioid consumption was significantly reduced in the patients receiving isb but they found no significant difference in opioid consumption between the isb and isb + ga groups. patient satisfaction scores in the isb and isb + ga groups were significantly higher than scores reported by ga only patients. patients in the isb group reported less nausea and vomiting as compared to the other groups and reported their experience as “better than expected” more frequently than patients in both the ga and the ga + isb groups. in a retrospective chart review, yauger and colleagues7 compared outcomes between patients undergoing either shoulder arthroscopy or knee arthroscopy receiving ga or ra in a military same day surgery unit (sdsu) in a certified registered nurse anesthetist (crna) only practice model. the study reviewed 342 cases, with 161 ga and 181 ra. combined ga and ra procedures were excluded. regional anesthetic techniques included interscalene block (isb) for shoulder arthroscopy or femoral nerve block (fnb) for knee arthroscopy. results included a 13 minutes longer pre-op time for ga patients than the ra group, with a slightly less intra-operative time. the ga group also utilized 25.9 minutes less anesthesia provider time. the ra group spent 20.3 minutes less time in pacu than did the ga group and sdsu. pain scores post-operatively were significantly increased in the ga group, with increased morphine equivalent opioid use by the ga group relative to the ra group. this study suggests that crna-administered regional anesthesia provided a safe and effective alternative anesthetic for outpatient shoulder and knee arthroscopy, with improved quality indicators such as a reduction of ponv, pain, and opioid consumption as compared to ga. gonano and colleagues8 evaluated the differences between ultrasound (us) guided isb and ga for arthroscopic shoulder surgery. the total sample size was 40 patients with equal distribution into each group. researchers recorded all drugs and disposable equipment used and evaluated each method in terms of cost. other costs were calculated considering anesthesia-related workflow and total anesthesia time, total time in pacu, and readiness for discharge. a decreased total cost for patients receiving isb (33 +/9 €) was reported as compared to the ga group (41 +/7 €). the authors found that anesthesia time was significantly less in the isb group [12 (+/4) minutes] versus the ga group [23 (+/6) minutes]. pacu time was significantly reduced in the isb group (45 +/17 min) versus the ga group (70 +/20) minutes. the review of the literature suggests that ra not only allows for excellent surgical anesthesia, but also reduces length of patient stay, intra and post-operative opioid requirements, post-operative pain, ponv, and overall cost, while simultaneously improving patient satisfaction scores. the review also demonstrates a need for research to explore best practices specific to rural anesthesia practice. purpose of the study although there is a significant body of literature comparing regional anesthesia to general anesthesia, there are few studies looking at these techniques for shoulder surgery specifically in the anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 3 2017 page 16 rural population. the purpose of this retrospective chart review was to characterize the complication rate and outcomes among a group of patients receiving regional anesthesia in patients undergoing shoulder surgery in the rural setting utilizing a certified registered nurse anesthetist only model. complications measured in this review included nausea, vomiting, and delayed discharge. need for opioid analgesia was also measured. materials and methods design the institutional review board at the university of detroit mercy approved the project through expedited review. it is a retrospective chart review of patients undergoing shoulder surgery at hillsdale community health center (hchc) during 2014. hchc utilizes a crna only anesthesia practice model. it has 47 acute care beds and is located in southwestern michigan, 112 miles from detroit, in a county of approximately 47,000 people. the project was also approved by the administration of hchc who granted access to the patient electronic records. data collection the authors developed the data collection sheet used to gather patient information. (appendix 1) inclusion criteria included all patients undergoing shoulder surgery. the hospitals electronic medical system was utilized to retrieve records of patients through coding indicating they met inclusion criteria during the identified time period. to maintain confidentiality and anonymity, patient identifiers were not collected. collected data included patient demographics of gender, age, asa status, height, weight, and bmi. in addition preoperative diagnosis, surgical approach (open versus arthroscopic), surgical procedure, and type of anesthetic administered were recorded. times were measured reflecting anesthesia time, operating room time, and pacu time in minutes. the occurrence of nausea or vomiting was recorded as was prophylactic and rescue agents administered. pain measurements upon arrival to pacu, one hour later, and upon discharge from pacu were also recorded using the vas. opioid and other analgesic administration was recorded for pre, intra, and postoperative periods. results seventy nine patient records were reviewed. three patient records were excluded because of incompleteness of crucial data in the records leaving a sample population of 76 patients. descriptive analysis of the data was performed. demographic data is summarized in table 2. the most common preoperative diagnosis was rotator cuff tear (47.4%) followed by impingement syndrome (14.5%) and ankylosis (6.6%) with a variety of other diagnoses comprising the remainder in near equal numbers. the recorded procedure was most often shoulder arthroscopy (76.3%). a combined ra with ga technique was performed on nearly all patients so comparisons between ra and ga were not attainable. (table 3) bupivicaine 0.5% was utilized in 65 (85.5%) of the ra procedures with ropivicaine 0.5% utilized in the remainder. only 3 patients (3.9%) received preoperative analgesia. pain scores as measured by vas reflected effective analgesia. (table 4) the overall rate of ponv as well as rescue medication for ponv was low. prophylaxis for ponv was administered to most patients with ondansetron 4 mg alone or in combinations with dexamethasone 4mg or metaclopromide 10mg most often utilized. (table 5) the mean anesthesia time was 127.3 minutes with mean or time of 121.2 minutes. mean time in pacu was 134.6 minutes. blocks were administered in the preoperative holding area so that or time was not prolonged. two blocks were deemed to be ineffective in pacu and were re-administered. one patient was admitted unplanned for intractable pain. no other adverse events were reported. discussion this analysis provided current data related to demographics and outcomes in patients undergoing shoulder surgery in a crna-only rural practice setting. quality outcomes data are crucial to continuously provide supportive data speaking to the safety and efficacy of crna solo practice. the descriptive data attained demonstrates effective ra as a supplement to ga. as a result, a decrease in mean alveolar concentration (mac) of inhaled agent can be assumed and small intraoperative doses of opioid were required allowing a reasonable assumption of a correlation to reduced opioid side effects. a very low incidence of ponv occurred suggesting that low opioid use, inhalation agent, and/or prophylactic antiemetic administration was effective. the ponv incidence was lower than reported in the studies reviewed here and lower than the incidence reported by gohl and colleagues9 in a 2001 study comparing isb to ga techniques in which they found 66% of ga patients experienced nausea and 25% for those receiving isb and ga combined. the measured mean anesthesia time represented only 6.1 minutes longer than or time. so the institutional practice of performing the regional technique in the preoperative holding area did not significantly increase valuable time in the or. this study is not without limitations. foremost, a randomized prospective design comparing ga to ra or a longer retrospective study period to mine data from patients who underwent shoulder surgery prior to the predominate practice of most frequently employing ra would provide better comparative data. since the target population was a rural setting with crna-only practice the findings cannot be generalized to larger facilities with other anesthesia care models. this study provides supportive data that ra added to the anesthesia plan for shoulder surgery in a rural, crna-only practice is safe, effective and efficient. although questions could not be answered through comparison of groups in this study, the data revealed low incidences of postoperative adverse events, effective analgesia during the postoperative period, and minimal anesthesia time beyond operating room time needed. implications for clinical practice and future research the current trends in healthcare in the united states point towards increasing patient satisfaction and quality while reducing costs. regional anesthesia has long been recognized as a safe alternative or adjunct to general anesthesia in select patient populations and surgical procedures. as the reviewed literature anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 3 2017 page 17 suggests, a regional approach to outpatient shoulder surgery can reduce costs and improved outcomes, with the added benefit of improved patient satisfaction. future research is needed specific to crna-only practice models and rural settings and should include controlled randomized trials to evaluate outcomes in groups consisting of ga, ga+ra, ra + sedation and even ra alone in select populations. research exploring the potential benefits of the use of ultrasound-guided blocks versus more traditional approaches and the use of lower doses of local anesthetics and optimization of outcome measures need also to be conducted. further, it may prove beneficial to evaluate the effectiveness of continuous infiltration of local anesthetic in the outpatient setting. an additional area of future research should include a focus on rural anesthesia and the costs associated with providing anesthetic care in this setting. this review of the current literature as well as the descriptive evaluation of this practice points to promising reduction of costs and increased efficiency, both areas that could drastically impact the bottom line in the often budget-compromised rural healthcare setting. table 1-data extraction authors/study design, purpose and sample results and conclusions critique of strengths and weakness hadzic a, williams ba, karaca pe. et al. for outpatient rotator cuff surgery, nerve block anesthesia provides superior same-day recovery over general anesthesia. anesthesiology. 2005; 102:1001–1007. design: prospective, randomized study comparing the use of isb to ga for outpatient shoulder surgery. purpose: to compare which technique (nerve block vs. ga) provides more efficient recovery and greater patient satisfaction. sample: 50 patients result: * 76% of isb patients and 16%of ga patients bypassed pacu * 0 isb patients and16% of ga patients were admitted * 0 (0 %) isb patients and 20 (80 %) ga patients were treated for pain in pacu * discharge time for isb was 123 +/57 min and 286 +/ 100 min for ga patients conclusions: the authors conclude that isb increased pacu bypass, faster same-day recovery, better analgesia, and fewer adverse events following outpatient rotator cuff surgery as compared to ga. strengths: randomized, blinded study aldrete scoring used on all patients initially to assess ability to bypass pacu follow-up was through 2 week period weaknesses: small sample size ga patients received ponv prophylaxis, isb patients did not ga patients received nitrous oxide 50%, an agent known to produce ponv authors/study design, purpose and sample results and conclusions critique of strengths and weakness lehmann l, loosen g, weiss c, schmittner m. interscalene plexus block versus general anaesthesia for shoulder surgery: a randomized controlled study. eur j orthop surg traumatol. 2015; 25(2) 255-61. doi: 10.1007/s00590-014-1483-3. epub 2014 may 15. accessed june 4th, 2015 design: randomized, controlled, clinical trial purpose: evaluates the post-op opioid consumption in patients receiving isb, isb + ga, or ga alone for shoulder arthroscopy sample: 120 patients total. isb: n= 40 isb + ga: n= 40 ga: n= 40 result: * opioid requirements of isb and isb + ga were similar and less than ga alone. * isb had significantly higher patient satisfaction scores * isb led to significantly less ponv and lower pain scores than ga or ga + isb * isb had increased rate of bypassing pacu and discharge from the recovery room than isb or isb + ga conclusions: when compared to ga, patients receiving isb or isb + ga had a reduction in post-op opioid consumption, time to oral intake and strengths: • randomized, blinded study • large sample sizes weaknesses: • the authors cite their choice of la and volume of dosing as a weakness of the study anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 3 2017 page 18 authors/study design, purpose and sample results and conclusions critique of strengths and weakness gonano c, kettner sc, ernstbrunner m, schebasta k, chiari a, marhofer p. comparison of economical aspects of interscalene brachial plexus blockade and general anesthesia for arthroscopic shoulder surgery. british journal of anaesthesia. 2009; 103 (3): 428–33 (2009) doi:10.1093/ bja/aep173. accessed june 4th, 2015. design: randomized clinical trial purpose: this study was designed to evaluate the potential economic advantage of usguided isb vs. ga for arthroscopic shoulder surgery. the emphasis in this study is placed on the use of ultrasound for block placement and the economic impact vs. ga. sample: 40 patients total isb group: n= 20 ga group: n= 20 result: * costs are minimally lower in the isb group compared to the ga group. cost savings seen in faster turnover time when isb performed in block room. * pacu time, opioid use, ponv rates all reduced in the isb group. * 10% of isb patients needed vasopressor and fluid therapy vs. 60% of ga patients. conclusions: isb is a cost-effective method of providing anesthesia for arthroscopic shoulder surgery. isb is associated with less total anesthesia related cost and improved time efficacy. strengths: • looked specifically at costs • looked at us-guided blocks weaknesses: • small sample size • australian study may not be able to extrapolate to us anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 3 2017 page 19 authors/study design, purpose and sample results and conclusions critique of strengths and weakness yauger, y, bryngelson j, weiss c, et al. patient outcomes comparing crna-administered peripheral nerve blocks and general anesthetics: a retrospective chart review. aanaj. 2010.78(3) 215-220. design: retrospective chart review purpose: to compare quality indicators and operative time demands between patients undergoing shoulder or knee arthroscopy under ga vs. rb. sample: 342 patients undergoing shoulder or knee arthroscopy, with either ga or ra. ra in this study refers to either interscalene block for shoulder arthroscopy or femoral nerve block for knee arthroscopy. result: * the ga group used 25.9min less anesthesia provider time overall but spent 20.3 min longer in pacu than the ra group. * 15.5% of ga patients had ponv vs. 10.0% of rb patients, a statistically insignificant difference. * ra patients had a significant decrease in pain scores postoperatively and used less opioid than the ga group. * 12 patients in the ra group bypassed the pacu, while no patients in the ga did. conclusions: significantly less opioid use and pain scores when ra is used over ga. strengths: • large sample size • crnaonly study weaknesses: • only asa 1 and 2 patients. • only ga or rb, no combined technique patients • retrospective study anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 3 2017 page 20 table 2 demographics n =76 gender age years weight kg bmi kg/m2 asa status m = 37 (51%) 1=1 mean f = 39 (49%) 52.9 83 30.4 2= 3 min 19 51 18.2 3= 52 max 83 159 51.8 4=1 table 3 techniques anesthetic airway adjunct surgical approach ra+ga= 68 (90%) ett= 65 open= 58 ga only= 6 (8%) lma= 3 arthroscopy= 15 ra+ sedation= 2 (2%) not indicated= 3 table 4 vas scores n =76 vas arrival vas 1 hr. vas dc mean 1.27 1.69 0.37 reported score of 0 59 (77.6%) 48 (63.2%) 59 (77.6%) table 5 ponv data postop nausea postop vomiting ponv prophylaxis ponv rescue 5 (6.6%) 2 (2.6%) 69 (90.8%) 3 (3.9%) references 1. american hospital association website. aha research policy page. the opportunities and challenges for rural hospitals in an era of health reform http://www.aha.org/research/policy/2011.shtml accessed june 4th, 2015. 2. ozzeybek d, oztekin s, mavioglu o, et al. comparison of the haemodynamic effects of interscalene block combined with general anaesthesia and interscalene block alone for shoulder surgery. the journal of international research. 2003; 31: 428433. 3. fredrickson mj, krishnan s, chen cy. postoperative analgesia for shoulder surgery: a critical appraisal and review of current techniques. anaesthesia. 2010; 65: 608-624. 4. abdallah fw, halpern sh, aoyama k, brull r. will the realbenefits of single-shot interscalene block please stand up? a systematic review and meta-analysis. anesthesia & analgesia. 2015; 120(5) 1114-1129. 5. hadzic a, williams ba, karaca pe. et al. for outpatient rotator cuff surgery, nerve block anesthesia provides superior same-day recovery over general anesthesia. anesthesiology. 2005; 102:1001–1007. 6. lehmann l, loosen g, weiss c, schmittner m. interscalene plexus block versus general anaesthesia for shoulder surgery: a randomized controlled study. eur j orthop surg traumatol. 2015; 25(2) 255-61. doi: 10.1007/s00590-014-1483-3. epub 2014 may 15. accessed june 4th, 2015 7. yauger, y, bryngelson j, weiss c, et al. patient outcomes comparing crna-administered peripheral nerve blocks and general anesthetics: a retrospective chart review. aanaj. 2010.78(3) 215-220. 8. gonano c, kettner sc, ernstbrunner m, schebasta k, chiari a, marhofer p. comparison of economical aspects of interscalene brachial plexus blockade and general anesthesia for arthroscopic shoulder surgery. british journal of anaesthesia. 2009; 103 (3): 428–33 (2009) doi:10.1093/bja/aep173. accessed june 4th, 2015. 9. gohl mr, moeller rk, olson rl, vacchiano ca. the addition of interscalene block to general anesthesia for patients undergoing open procedures. aanaj. 2001. 69(2) 105-109 anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 3 2017 page 21 http://www.aha.org/research/policy/2011.shtml appendix 1 data collection tool case number (1, 2, 3 etc.):________ demographics age: _______gender: male ______ female _____ height (cm): weight (kg): bmi (kg/m2): asa status _________ co-morbidities: _________________ inpatient ______ outpatient________ diagnosis: ________________________________________ upper extremity surgical procedure: _________________________________________________ surgical approach: open incision____________ scope________________ type of anesthesia _________regional and general anesthesia type of block: _________________ general using lma: _____ oet: ________ _________regional with sedation type of block______________________ _______ general without block _______ local/mac comments: _______________________________________ or and pacu times (minutes) total or time _____total anesthesia time: ______ total pacu time: ___________ perioperative data preoperative pain medications opioid: _____________ amount: _____________ route: iv______ po______im_____ nsaid: _____________ amount: ____________ route: iv______ po______im_____ acetaminophen amount: ____________ route: iv______ po______ other type: ______________ amount: _____________ route: iv______ po______im_____ intraoperative pain medications opioid: _____________ amount: _____________ route: iv______ po______im_____ nsaid: ______________ amount: ____________ route: iv______ po______im_____ acetaminophen amount: _____________ route: iv______ po______ other: ______________ amount: _____________ route: iv______ po______im_____ postoperative pain management local anesthesia infiltrated at incision site (by surgeon): yes____ no_____ catheter placed for post op pain: yes______ no_______ pain scores in pacu: arrival vas _______ 1 hour vas_______ pain score at discharge: vas______ comments: ________________________ pain medication use in pacu opioid: ______________ amount: _____________ route: iv______ po______im_____ nsaid: ______________ amount: _____________ route: iv______ po______im_____ acetaminophen: amount: _____________ route: iv______ po______ other: ______________ mount: _____________ route: iv______ po______im_____ ponv and treatment nausea: (y/n) vomiting: (y/n) ponv prophylaxis given: drug: dose: route: ____________ rescue meds for ponv: drug: dose: route: ____________ complications delay in discharge: (y/n) reason: _______________ length of delay: _______________ unplanned postop hospital admission: (y/n) reason___________________________ _ other: ______________________________________________________ anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 3 2017 page 22 volume 6 no. 6 2018 educated hand publishing llc “the science behind the art” volume 6 no. 6 2018 anesthesia ejournal online issn 2333-2611 page 26 using video-assisted technology and simulation to transform a nurse anesthesia machine and equipment course rachel marie smith-steinert, dnp, crna1 melissa willmarth-stec, dnp, cnm, aprn, facnm, faan2 affiliation: 1. assistant program director-nurse anesthesia, university of cincinnati, college of nursing 2. professor & associate dean for evaluation and educational innovation, suny downstate college of nursing funding/conflict of interest disclosure: the authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest keywords: anesthesia, simulation, anesthesia machine, nurse anesthesia curriculum, nurse anesthesia introduction anesthesia safety has dramatically improved, and morbidity and mortality directly related to anesthesia are uncommon. human error related to the misuse of the anesthesia machine and equipment, however, remains at 14% to 30% of all intraoperative problems.1 according to the american society of anesthesiologists closed claims project database, injury claims related to anesthesia machines have decreased to 1% of total claims but the results continue to be disastrous.2 patient outcomes in anesthesia-machine-related claims from 1990 to 2011 (n = 40) included anesthesia awareness (n = 9, or 23%), pneumothorax (n = 7, or 18%), and severe injury (death or permanent brain damage). the majority of these claims (85%) involved provider error with (n = 7) or without (n = 27) equipment failure.2 understanding how to use the anesthesia machine and how to troubleshoot when problems arise are paramount for nurse anesthesia practice. abstract introduction: understanding how to use the anesthesia machine and how to troubleshoot when problems arise are paramount for nurse anesthesia practice. simulation can provide a low-risk setting that allows students to learn in an environment representative of operational conditions. the purpose of this article was first to determine if simulation was an appropriate teaching modality to incorporate into the anesthesia machine course and second to explore the outcomes of utilizing such a modality in a traditional course. methods: this 2 group post-test design measured anesthesia machine learning in a traditional classroom and after introduction of simulated operating room experiences. using the food and drug administration (fda)-approved anesthesia machine checklist, a simulation exercise was formulated to review the basic function of the machine. students were divided into groups and taken to the hospital operating room twice. the first session reviewed the fda checklist and focused on the components and their intended usage and proper function. the second session discussed plausible machine failure scenarios. three written exams, a final oral exam, and course evaluations were used to measure preand post-exercise mastery of material, competency, student satisfaction, and confidence. results: there were no statistical differences in mastery of material or competency with the modified course. however, student satisfaction and perceived confidence increased. conclusion: use of simulation in the nurse anesthesia machine and equipment course allowed students to practice infrequent events that have grave consequences. changing the way that nurse anesthesia programs teach this course could not only provide safer, more competent providers but also improve anesthesia safety overall. aej anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 6 2018 page 27 one of the first courses in any nurse anesthesia curriculum is focused on the safe use of the anesthesia machine and equipment. novice nurse anesthesia students must have a firm understanding of the function of the machine to begin to learn how to safely provide anesthesia. traditionally, anesthesia machine and equipment courses have been taught with a didactic focus reinforced with some clinical observation time to see how the machine is used. the course can be difficult for students for numerous reasons. students have usually had little to no exposure to anesthesia machines as registered nurses. the properties that guide the design and use of the machine are rooted in principles of chemistry and physics, both of which are scant in undergraduate nursing programs. the value of early observation time has been questioned owing to the novice student’s lack of anesthetic knowledge. varying teaching modalities must be considered to ensure students master this vital material. the most recent institute of medicine initiative, the future of nursing, endorses simulation as a teaching methodology of the future.3 simulation can provide a low-risk setting that allows students to learn in an environment representative of actual operational conditions.4 a course using simulation and active learning exercises was created for novice nurse anesthesia students to improve course delivery and achievement of the student learning outcomes. the goals of this program were to increase understanding of the material, increase the students’ active participation, improve written and oral exam results, and improve student evaluations of the course. the purpose of this article was first to determine whether simulation was an appropriate teaching modality to incorporate into the anesthesia machine course and second to explore the outcomes of utilizing such a modality in a traditional course. malcolm knowles, an american educator, is credited with the theory of andragogy, that is, the art and science of helping adults learn.5 knowles believed that 6 factors distinguish the adult learner. self-directedness; accumulation of past experience, which becomes a resource for learning; readiness to learn; application of knowledge, which is problem-centered; internal motivation to learn; and the need to know why something should be learned all shape the adult learner.6 knowles’s assumptions of the adult learner are applicable to nurse anesthesia students. these assumptions of adult learning are often in conflict with a traditional, teacher-centered approach of didactic lecturing. in order for one to effectively teach adults, one must know how adults learn. clapper7 states in his review of literature concerning adult learning theory that adults learn from experience in a way that is simply not possible from instruction or information delivery alone. clapper advises educators to put away powerpoint (microsoft) slide presentations and instead use project-based learning to teach for understanding. clapper writes that health profession educators must move past old methodologies, despite their utility in the past.7 as curtin et al8 explain in their qualitative review of a simulation program, the 4 learning styles—visual, auditory, tactile, and kinesthetic—are all incorporated in a simulation activity. the authors explain how simulation promotes the learner’s knowledge acquisition on a deeper level by the activity of active participation. likewise, lasater et al9 describe how the active role permits deeper learning: understanding more, remembering longer, and more success in evaluation. in order for students to really learn, lasater et al9 state that educators must provide an environment that is proper for learning and resides in adult learning theory. zigmont6 also reiterates that simulation can allow a learner to move from basic knowledge to application, analysis, and finally synthesis, the highest level of comprehension. simulation adheres to the 2 most important tenets of adult learning: hands-on experience in a safe environment and provided guided reflection.6 when reviewing the literature concerning the incorporation of simulation into curriculum, issenberg et al’s10 expansive systematic review of 109 articles spanning from 1969 to 2003 must be included. high-fidelity simulation is demonstrated to be educationally effective and complements but does not duplicate medical education in patient care settings.10 issenberg at al10 state that simulation is best served to prepare learners to care for real patients. this review explains that simulation is an excellent tool to facilitate learning under the right quality conditions. grant et al11 echo the use of simulation in preparation for direct patient care, showing positive outcomes for learners involved in simulation activities before clinical practice commences. in a systematic review and meta-analysis by cook et al,12 a comparison with no intervention and technology-enhanced simulation training in health profession education was examined. a follow-up systematic review was performed by cook et al13 that reviewed 82 studies and included 3498 participants. this article showed that simulation-based medical education (sbme) is an effective instructional design feature. the authors concluded that educators should consider using this approach.13 in mcgaghie et al’s14 systematic review, the meta-analysis was clear and unequivocal. outcomes favor sbme, and a growing body of evidence suggests that clinical skills acquired via sbme transfer directly to patient care. the authors concluded that enhancement of the traditional clinical educational model with evidence-based practice like sbme should be a high priority for medical education policy and research.14 learner satisfaction, confidence, and perceived competence are factors that are often discussed in the literature on the outcomes of simulation. in harder’s15 systematic review, 23 articles are reviewed that discuss the use of simulation in health profession education. in 21 of the studies, students evaluated their confidence and perceived skill level higher than did those who did not participate in simulations. laschinger et al16 specifically reviewed confidence, knowledge, and satisfaction in their systematic review. learner satisfaction was increased with simulation when used to learn clinical skills, with learners reporting that the models made learning easier.16 ruesseler et al17 looked at the satisfaction of medical students after simulation training versus traditional clinical teaching. statistically significant increases in satisfaction were noted for those students who completed simulations.17 a paucity of literature is available examining simulation use in nurse anesthesia education. however, in studies with anesthesia residents as participants, simulation has been demonstrated to be effective. mudumbai et al18 examined anesthesia residents in a prospective, descriptive study that evaluated basic anesthesia anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 6 2018 page 28 machine function and proper use. the authors created simulation scenarios in which participants had to troubleshoot machine malfunction in pairs. the authors suggested highfidelity simulation as a means to teach trainees equipment and machine function and examine management during a machine malfunction crisis. park et al19 looked at crisis management in the novice anesthesia resident. anesthesia residents completed either a traditional curriculum or one with added simulation to study infrequent but catastrophic events during anesthesia management. hypotheses were confirmed that the addition of event-specific simulation accelerated the management skills for that specific event.19 methods institutional review board (irb) approval was achieved before implementing this project. the project was granted irb exemption status owing to its quality improvement nature. consent was not necessary from participants owing to the quality improvement nature of the project; however, participants were informed of the project details, and clear objectives and desired outcomes were discussed. the setting of this project was a nurse anesthesia program in a college of nursing within a large, urban university. students included in this project were 25 first-semester, novice nurse anesthesia students enrolled in the anesthesia machine and equipment course. additionally, the students were registered nurses with 2 to 5 years of critical care nursing experience. planning for this project began 2 years before implementation, with a formal needs assessment. students (n=25) completed a comprehensive survey in which they were asked, at the completion of the course, what could have made the material easier to comprehend. students stated (84% of respondents) that machine component and function were difficult to understand when lectured on in class. students requested to see a “live” machine function and malfunction in a safe environment. additionally, faculty responses were solicited. all faculty (n=6) stated that simulation was an area the program needed to develop and explore how to incorporate into the curriculum. the director stated that program applicants often inquired about the use of simulation and its role in clinical preparedness. developing simulation usage in the program was seen as paramount by the nurse anesthesia faculty. these results demonstrated the faculty’s desire to implement simulation as a component in the curriculum. current students desired more hands-on time during the machine course and believed that additional time working on the machine checkout would improve comprehension and knowledge retention. on the basis of these data, several changes were made to the anesthesia machine course. these changes were supported by the literature on adult learning theory and simulation utilization in health care education. previously, the students spent the first weeks of the semester in the operating room. this activity was eliminated, which allowed more time for more active learning exercises with live machines. the course was examined to determine which lectures could be transferred from in-class lecture to an online delivery format. lectures covering basic scientific principles, patient equipment, and fire and electrical safety were chosen for video conversion, thus decreasing lecture time by 16 hours. using the anesthesia machine checklist approved by the food and drug administration (fda), an active learning exercise was formulated to review the basic function of the machine. students were divided into 4 groups with 6 students per group and were taken to the operating room twice for 1-hour periods. participants were encouraged to watch an online video covering the basic fda checkout of the fabius gs anesthesia machine (draeger) before their scheduled session. each session was completed in small groups led by an instructor. the first session reviewed the fda checklist with a focus on the components and their intended usage and proper function. students reviewed the checkout procedure once, step by step, to show the appropriate function of each component of the machine. students were able to ask questions and discuss each component (figure 1). the second session discussed plausible machine failure scenarios. students were then provided hands-on time to work in small groups to review the checkout procedure. checklists using the fda checkout of the anesthesia machine and possible anesthetic emergencies related to equipment error and misuse provided structure for these exercises (figure 2). during the modified course, the students completed the existing 3 written exams given in the initial course. at the completion of the course, a uniform oral exam was conducted in the operating room during which students completed the fda checklist from memory to demonstrate safety and proper function of the machine and answered questions on machine and equipment failure scenarios. students simulated checking the machine, determining its safety for use, and preparing for the induction of a patient by using a low-fidelity mannequin. at the completion of the exam, the exercise was reviewed and students were given feedback on their performances. time was also allotted for student questions to be answered. the written exams, final oral exam, and student evaluations of the course were evaluated after implementation of the new curricular changes. the outcomes measured were mastery of material, competency, and student satisfaction and confidence. mastery of course material was demonstrated by the 3 written exams. competency using the anesthesia machine and troubleshooting problems with its function was shown in the oral exam performance. student evaluations of the course were used to measure student satisfaction and confidence. means of the results of the written and oral exams were compared by using an unpaired t-test to determine statistical differences after implementation of the program. qualitative data from the student evaluation of the course were used to measure student satisfaction before and after implementation of the simulation and active learning exercises. results this quasi-experimental, nonequivalent control group design compared 2 groups of students: students from the previous semester enrolled in the lecture-based course and students from the simulation and active learning integrated course. written exam scores were used to demonstrate student mastery of course material. the mean scores on the written exam for the preintervention group were 81.36% for exam 1 (sd=4.58), 84.0% for exam 2 (sd=6.89), and 86.08% for exam 3 (sd=4.31). in the modified course, the mean scores for the written exams were anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 6 2018 page 29 80.36% for exam 1 (sd=3.77), 80.43% for exam 2 (sd=6.32), and 84.96% for exam 3 (sd= 6.36). an unpaired t-test was used to determine whether the changes in exam scores were statistically significant. for all 3 written exams, there was no statistically significant difference in scores from before to after the intervention. therefore, mastery of the course material was unchanged. results of the oral exam were used to demonstrate competency in troubleshooting and determining functionality of the anesthesia machine in the lecture-based course as well as the simulation and active learning integrated course. the mean result on the oral exam before the intervention was 92.5% (sd= 4.89) and that after the intervention was 94.25% (sd= 5.06). using the unpaired t-test, the difference between the 2 groups was statistically insignificant. thus, the ability to demonstrate competency after the course was modified was unchanged. university course evaluations are used annually to determine student satisfaction with the course and to give students an opportunity to give feedback to the instructor. these qualitative and quantitative data are compiled at the conclusion of the course. before the intervention, 82% of the students agreed with the statement that “course material was presented at an adequate pace.” qualitative data after intervention revealed statements such as: • “reviewing the machine checkout in small groups would be helpful. this information was overwhelming.” • “i think i would retain more information if i could have touched the machine.” • “it’s difficult to see and hear the components of the machine with 25 people in the room.” • “it would be nice to go over the checkout and have more hands-on time.” nine of 25 students (36%) commented on the need for more hands-on time with the machine and the instructor. after changes were made to the course, 91.7% (n=12) of the respondents strongly agreed with the statement, “[the] course material was presented at an adequate pace,” and 100% of the respondents strongly agreed with the statements, “this course strengthened my knowledge base and clinical skill as an anesthesia provider” and “physical and learning resources were adequate to meet course objectives.” qualitative data included: • “going to the or [operating room] in small groups was beneficial.” • “i feel adequately prepared to manage the machine.” • “going to the or with the instructor, for hands-on time with the machines, was helpful.” overall, the qualitative data showed increased satisfaction with the course and improved confidence of the students after the active learning exercises. discussion the results of this quality improvement initiative indicated that the use of simulation in the machine course was beneficial to student outcomes. although the results were equivalent in terms of mastery of information and demonstrated competency on the basis of the results of the written and oral exams, improvements were noted in active participation, student satisfaction, and confidence with program implementation. similar improvements were noted by harder15 and lashinger et al.16 these results and the literature support the use of simulation and active learning exercises in the anesthesia machine and equipment course. the limitations of this project include threats to internal validity such as selection bias. the design did not allow the same groups of students to be surveyed on both courses, before and after the intervention, because of the nurse anesthesia curriculum. each group of anesthesia students is composed of different age groups, genders, previous experiences, and learning styles. therefore, the group comparison was also biased by the composition of the class. additionally, only first-year, novice nurse anesthesia students are enrolled in the course. although the student input from the evaluations was helpful, this was the first course the students had taken in the nurse anesthesia program. therefore, they did not have other nurse anesthesia machine courses with which to compare this experience. threats to external validity were minimal because cohorts of nurse anesthesia students nationwide are required to meet similar standards for admission into programs. therefore, this sample can be considered representative of cohorts across programs. this intervention was strongly based on the addition of simulation to the course. for most of this project, the simulation laboratory was in its formative phase, under construction, with equipment slowly being purchased. low-fidelity mannequins were used because of their portability to the operating room. more realistic and accurate scenarios should be developed with high-fidelity equipment. simulation equipment and laboratory space is an immense investment for programs; highfidelity mannequins cost close to $100,000. the cost benefit for anesthesia programs must be evaluated before making this investment. there exists a paucity of research using computer adaptive technology and simulation in nurse anesthesia curricula. any research in this field will advance this area of study. future areas to further develop this project would include increased lectures online, availability of videos covering machine troubleshooting, and further troubleshooting scenarios with higher fidelity mannequins. developing more realistic scenarios incorporating rare events such as power outages, machine failure, and various equipment malfunctions could give novice students experience that they may never encounter in their training with live patients in the operating room. recording the oral exams and allowing students to watch their performance may also aid in the debriefing phase and provide more valuable feedback. simulation has been shown in the literature to improve the performance of health care providers, providing valuable experience in a low-risk setting. although rare, anesthesia machine and equipment errors can result in disastrous consequences, causing patient injury and death. the institute of medicine’s20 recent report describes the importance of improving patient safety in health care through the use of educational technologies to improve teaching and competence. use of simulation in the nurse anesthesia machine and equipment course allows students to practice infrequent events that have grave consequences. changing the way nurse anesthesia programs teach this course could not only provide safer, more competent providers but also improve anesthesia safety overall. summary of key points simulation has been shown in the literature to improve the performance of health care providers, providing valuable experience in a low-risk setting. although rare, anesthesia machine and equipment errors can result in disastrous consequences, causing patient injury and death. • understanding how to use the anesthesia machine and troubleshoot when problems arise is paramount for nurse anesthesia practice. • use of simulation in the nurse anesthesia machine and equipment course allows students to practice infrequent events that have grave consequences. • although increased mastery of material was not demonstrated to improve, confidence and satisfaction were increased. • changing the way nurse anesthesia programs teach this course could not only provide safer, more competent providers but also improve anesthesia safety overall. simulation session one activities • reviewed all steps of fda anesthesia machine checkout procedure • demonstrated automated and manual check of anesthesia machine • located backup cylinder supply and emergency airway equipment • discussed location and proper function of the following internal components 1. cylinder supply (high pressure leak determination) 2. first stage regulator 3. oxygen flush 4. flowmeters 5. pressure sensor shutoff valve 6. oxygen supply alarm 7. proportioning system 8. auxiliary flowmeter • reviewed proper function and check of the following external components 1. vaporizer (filling, changing, checking for a leak, competency) 2. absorber (changing canister, determining exhaustion & desiccation) 3. ventilator 4. scavenger system (suction supply, competency of positive and negative pressure relief valves) 5. breathing system (low pressure leak determination) • reviewed setting and tested function of following alarms 1. positive pressure alarm 2. volume alarms 3. pressure alarms 4. subatmospheric pressure alarm 5. oxygen analyzer 6. machine power failure alarm • reviewed function of various or tables • reviewed inclusion of asa monitors and determined competency figure 1. simulation session one on the fabius gs anesthesia machine (draeger). abbreviations: asa, american society of anesthesiologists; fda, food and drug administration; or, operating room. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 6 2018 page 30 simulation session two activities • discuss and demonstrate possible machine component failures and troubleshooting 1. look for vaporizer and nitrous flowmeters being “left on” 2. troubleshooting machine automated tests (internal software checks) 3. calculating oxygen cylinder and emergency supply 4. deciphering safety of pipeline supply 5. determining conditions when one would switch from pipeline to cylinder supply 6. troubleshooting suction issues 7. replace all “missing hoses” correctly 8. mimic obstruction in ventilator hoses (clinical scenarios when this might occur) 9. mimic obstruction in scavenger hoses (clinical scenarios when this might occur) 10. putting together breathing circuit components correctly 11. replacing galvanic/paramagnetic oxygen supply monitor 12. recognizing exhausted/expired carbon dioxide absorber canister 13. recognize high and low pressure leaks  is the leak acceptable? quantify the leak  where is the location of the leak?  how to “fix” the leak figure 2. session 2 on the fabius gs anesthesia machine (draeger). anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 6 2018 page 31 references 1. dalley p, robinson b, weller j, caldwell c. the use of high-fidelity human patient simulation and the introduction of new anesthesia delivery systems. anesth analg. 2004;99(6):1737-1741. https://doi.org/10.1213/01.ane.0000136804.46675.ea. 2. mehta s, 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meta-analysis. acad med. 2013;88(8):1178-1186. https://doi.org/10.1097/ acm.0b013e31829a365d. 14. mcgaghie wc, issenberg sb, cohen er, barsuk jh, wayne db. does simulation-based medical education with deliberate practice yield better results than traditional clinical education? a meta-analytic comparative review of the evidence. acad med. 2011;86(6):706-711. https://doi.org/10.1097/acm.0b013e318217e119. 15. harder bn. use of simulation in teaching and learning in health sciences: a systematic review. j nurs educ. 2010;49(1):2328. https://doi.org/10.3928/01484834-20090828-08. 16. laschinger s, medves j, pulling c, mcgraw r, waytuck b, harrison m. effectiveness of simulation on health profession students’ knowledge, skills, confidence and satisfaction. int j evid-based healthc. 2008;6:278-302. 17. ruesseler m, weinlich m, müller mp, byhahn c, marzi i, walcher f. simulation training improves ability to manage medical emergencies. emerg med j. 2010;27(10):734-738. https://doi.org/10.1136/emj.2009.074518. 18. mudumbai sc, fanning r, howard sk, davies mf, gaba dm. use of medical simulation to explore equipment failures and human-machine interactions in anesthesia machine pipeline supply crossover. anesth analg. 2010;110(5):1292-1296. https:// doi.org/10.1213/ane.0b013e3181d7e097. 19. park cs, rochlen lr, yaghmour e, et al. acquisition of critical intraoperative event management skills in novice anesthesiology residents by using high-fidelity simulation-based training. anesthesiology. 2010;112(1):202-211. https://doi. org/10.1097/aln.0b013e3181c62d43. 20. institute of medicine. the future of nursing: leading change, advancing health. washington, dc: national academies press; 2011. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 6 2018 page 32 https://doi.org/10.1213/01.ane.0000136804.46675.ea https://doi.org/10.1097/aln.0b013e3182a10b5e https://doi.org/10.1097/cnq.0b013e3181a27e0f https://doi.org/10.1097/cnq.0b013e3181a27e0f https://doi.org/10.1053/j.semperi.2011.01.002 https://doi.org/10.1016/j.ecns.2009.07.003 https://doi.org/10.3928/01484834-20081101-02 https://doi.org/10.1080/01421590500046924 https://doi.org/10.1080/01421590500046924 https://doi.org/10.1001/jama.2011.1234 https://doi.org/10.1097/acm.0b013e31829a365d https://doi.org/10.1097/acm.0b013e31829a365d https://doi.org/10.1097/acm.0b013e318217e119 https://doi.org/10.3928/01484834-20090828-08 https://doi.org/10.1136/emj.2009.074518 https://doi.org/10.1213/ane.0b013e3181d7e097 https://doi.org/10.1213/ane.0b013e3181d7e097 https://doi.org/10.1097/aln.0b013e3181c62d43 https://doi.org/10.1097/aln.0b013e3181c62d43 146-##_other-1023-1-11-20211222.jpg volume 9no. 3 2021 educated hand publishing llc “the science behind the art” volume 9 no.3 2021 anesthesia ejournal online issn 2333-2611 page 5 anesthetic management of venous gas embolism with hepatectomy yoshiya kunisawa, bsn, rn affiliation: texas christian university grant/financial support: none biographical data: yoshiya kunisawa is graduate student pursing a doctor of nursing practice in anesthesia from texas christian university school of nurse anesthesia. keywords: venous gas embolism, venous air embolism, ge, vae, hepatectomy abstract this is a case review of the intraoperative management of a 46-year-old male patient with a history of stage iv sigmoid colon adenocarcinoma with metastasis to the liver that presented for a robotic assisted sigmoidectomy and partial hepatectomy and had an intraoperative venous gas embolism that resulted in acute hemodynamic instability. venous gas embolism can be a life-threatening intraoperative event that requires fast recognition of the symptoms and appropriate interventions in response to the patient changes. evidence suggests that venous gas embolisms are very common with certain procedures but often subclinical. preventative measures, early recognition, and prompt treatment of venous gas embolisms are important interventions to minimize the risk for any significant hemodynamic instability and any resulting neurological or cardiovascular sequelae. aej volume 8no. 3 2020 educated hand publishing llc “the science behind the art” volume 8 no.3 2020 anesthesia ejournal online issn 2333-2611 page 10 patient blood management brianna berman, bsn, rn, affiliation: texas christian university funding/conflict of interest disclosure: none abstract patient blood management (pbm) recommendations can help providers manage anemia and assist in transfusionrelated decision-making. patient blood management (pbm) is based on three pillars: treatment of underlying anemia, minimizing blood loss, and the use of transfusion thresholds. establishing hemoglobin levels that dictate transfusion thresholds can be either restrictive (transfusing at lower thresholds) or liberal (transfusing at higher thresholds). current literature recommends restrictive transfusion thresholds (hemoglobin less than 7 gm/dl) with consideration for individual patient status. a 56-year old male underwent an emergent exploratory laparotomy to locate a source of bleeding four days after having a hemicolectomy. he received one unit of packed red blood cells (prbcs) in the intensive care unit overnight and arrived in the operating room (or) on a phenylephrine drip. after induction, the patient required a vasopressin drip as well. the patient remained hemodynamically unstable and his hemoglobin was 9.8 g/dl, thus, the decision was made to administer one unit of prbcs in the or. the patient remained unstable throughout the case and a hemoglobin recheck was 9.5 g/dl, so a second unit of prbcs was given. the transfusion threshold utilized in this case was liberal (less than 10 g/dl). utilization of pbm can help guide transfusion decisionmaking and decrease the number of blood products given without increasing patient morbidity or mortality. aej powerpoint template ©2009 texas christian university, center for instructional services. for educational use only. content is the property of the presenter and their resources. purpose • the purpose of this case study is to explore patient blood management (pbm) recommendations and transfusion thresholds. introduction • blood transfusions are often a necessary component of anesthetic management of the operative patient. • however, transfusions can have serious potential risks ranging from an allergic rash to a hemolytic reaction, and even death. • establishing guidelines for pbm can help mitigate risks and ensure that blood transfusions are appropriate. • pbm is based on 3 “pillars”: treatment of underlying anemia, minimizing blood loss, and use of transfusion thresholds.1 • pbm helps determine in which patients the benefits of transfusion outweigh the risks. literature search • a literature search was performed utilizing these databases: medline, embase, and pubmed. • six peer-reviewed articles published within the last eight years fit inclusion criteria and were selected. recommendations • transfusion guidelines (see table 2) • controlled hypotension (map 50-60 mmhg)6 • goal-directed fluid therapy, fluid bolus pre-op6 • avoid hypothermia and acidosis6 • coagulation studies1 • cell salvage1 • accurate recording of intra-operative blood loss1 • facility-specific pbm5 • clinical decision-making tools incorporated into electronic documentation5 patient blood management brianna berman, bsn, rn, texas christian university hemoglobin transfuse? 6 gm/dl or less stable patient 7 gm/dl or less stable patient 7.5 gm/dl or less cardiac surgery 8 gm/dl or less cardiac disease 10 gm/dl or greater unstable patient, active bleed vs pre-op post-op hr 125 120 bp 120/75 97/58 spo2 99% on ra 87% on 100% fio2 rr 24 14 ph 7.455 7.194 pco2 18.6 45.1 po2 77.8 315.6 hco312.8 17 base deficit -8.8 -10.8 hemoglobin 9.8 9.5 case study • 56 year-old male, 157.9 kg, bmi 47.2 presenting for emergent exploratory laparotomy for suspected bleeding after a hemicolectomy 4 days prior • history: hypertension, hypercholesterolemia, copd, adhd, and diabetes • patient received 1 unit prbcs in icu overnight • pre-op vs: see table 1 • patient arrived from icu with a phenylephrine drip at 6 mcg/min • after induction, the patient’s bp dropped to 80/50 and was treated with: 600 mcg phenylephrine, 100 mg calcium chloride, 3 units vasopressin, and 750 ml 5% albumin. phenylephrine drip was increased to 30 mcg/min and a vasopressin drip at 0.04 units/min was added. • initial hemoglobin was < 10gm/dl so 1 unit prbcs was given as the patient was unstable. repeat hemoglobin was 9.5 so a second unit was given. • hemostasis was obtained and patient was taken to icu intubated. • post-op vs: see table 1 • the following morning the patient coded, was made a dnr by family, and ultimately passed away. references 1. zacharowski k, spahn dr. patient blood management equals patient safety. best practice & research clinical anaesthesiology. 2016;30(2):159-169. doi:10.1016/j.bpa.2016.04.008. 2. gammon r. clinical practice guidelines from the aabb: red blood cell transfusion thresholds and storage. blood news. 2018:1-2. accessed december 18, 2019. available from: https://hospitals.vitalant.org/getattachment/home/2018-01-jan.pdf.aspx?lang=en-us. 3. mueller mm, remoortel hv, meybohm p, et al. patient blood management recommendations from the first international consensus conference, frankfurt, germany. jama. 2019;134:983-997. doi:10.1182/blood-2019-130601. 4. carson jl. red blood cell transfusion: a clinical practice guideline from the aabb. annals of internal medicine. 2012;157(1):49-58. doi:10.7326/0003-4819-156-12-201206190-00429. 5. sadana d, pratzer a, scher lj, et al. promoting high-value practice by reducing unnecessary transfusions with a patient blood management program. jama internal medicine. 2018;178(1):e1e7. doi:10.1001/jamainternmed.2017.6369. 6. cinnella g, pavesi m, gasperi ad, ranucci m, mirabella l. clinical standards for patient blood management and perioperative hemostasis and coagulation management. position paper of the italian society of anesthesia, analgesia, resuscitation and intensive care (siaarti). minerva anestesiologica. 2019;85(6):635-664. doi:10.23736/s0375-9393.19.12151-7. 7. bakaeen f. will you need a blood transfusion after open heart surgery? health essentials from cleveland clinic. https://health.clevelandclinic.org/blood-transfusions-after-open-heart-surgery/. published march 28, 2017. accessed february 19, 2020. summary • pbm recommends utilizing strict transfusion thresholds unless the patient is unstable, or they are overtly bleeding. • controlled hypotension and goal-directly fluid therapy can decrease the need for transfusion. • consider the risks versus benefits of transfusion. • adhering to pbm reduces the number of blood products utilized, with no increase in patient morbidity/mortality.4,5,6 • careful consideration of case-specific needs will help guide pbm. discussion • avoiding anemia in surgical patients is important in order to maintain the blood’s oxygen carrying capacity and maintain adequate atp for cellular metabolism, and to ensure toxic waste such as co2 is removed. • major risks of blood transfusions include hemolytic reactions, acute lung injury, volume overload, and deadly infections such as hepatitis and hiv.2 • all patients should be screened for anemia and any underlying causes should be treated prior to surgery.3 iron supplementation and short-acting erythropoietin are potential treatments.3 • stricter transfusion thresholds (hemoglobin <7 gm/dl) are favorable.3 transfusion thresholds increase with cardiac surgery, underlying cardiac disease, active bleeding, and symptomatic anemia.3,4 (see table 2) • if a transfusion is deemed necessary, sadana et al. recommends the phrase “why give 2 when 1 will do?”.5 furthermore, a provider should wait 15 minutes after transfusion to re-check a hemoglobin to assess if further intervention is needed.2 • several anesthesia-specific interventions can be utilized to minimize the need for blood transfusions.6 • coagulation studies such as rotem or teg can guide blood management and determine what type of blood product is needed.1 • cell salvage techniques decrease transfusion needs and avoid potentially creating anemia pre-operatively as autologous transfusions can do.1 • every facility should have a pbm system or transfusion guidelines in place.5 case-specific discussion • in this case, a liberal transfusion threshold was utilized (hemoglobin was less than 10 gm/dl). • according to pbm guidelines, this was appropriate as the patient was hemodynamically unstable. • one alternative to giving prbcs would have been to get coagulation studies first to determine if prbcs were the best option. treating acidosis more aggressively may also have helped. 7 table 2. transfusion recommendations 4 table 1. patient vital signs patient blood management treatment of anemia minimizing blood loss transfusion thresholds educated hand publishing llc “the science behind the art” volume 8 no.3 2020 anesthesia ejournal online issn 2333-2611 page 11 educated hand publishing llc “the science behind the art” volume 7 no. 1 2019 anesthesia ejournal online issn 2333-2611 page 1 case report of acute pulmonary edema and sudden death after heart surgery joshua m. thigpen, dnp, crna affiliation: dr thigpen was a student at texas christian university at the time of writing this article. funding/conflict of interest disclosure: none keywords: cardiac surgery, cardiopulmonary bypass, transfusion-related acute lung injury, protamine reaction, noncardiogenic pulmonary edema introduction aside from the inherent risks of heart surgery and individual morbidities, unforeseen risks are sometimes overlooked and can be devastating. these covert problems in the time period of coronary artery bypass graft surgery usually manifest after cardiopulmonary bypass (cpb), after hemodynamic stabilization, when complications are less likely. the post-cpb period is when protamine sulfate and blood products are commonly administered. protamine sulfate reverses the effects of the heparin that was administered before and during cpb to prevent coagulation. in this case, a 47-year-old man undergoing several procedures on his heart and requiring cpb experienced fulminant pulmonary edema after the administration of protamine and blood products. it is unclear whether the protamine or the blood products were responsible, because transfusion-related acute lung injury (trali) and severe reactions to protamine have similar presentations. unfortunately, the severity of the resulting pulmonary edema led to this patient’s death. anesthesia professionals should be familiar with the risk factors, presentation, and treatment for each. abstract a 47-year-old man underwent aortic valve replacement surgery. after cessation of cardiopulmonary bypass, the patient exhibited refractory hypoxia, fulminant pulmonary edema, and hypotension and ultimately died less than 1 hour after his arrival to the intensive care unit. the patient may have experienced either a severe type iii reaction to protamine sulfate or a transfusion-related acute lung injury. both of these conditions can produce hypoxia, pulmonary edema, and hypotension. anesthesia professionals must be able to identify patients at risk for both conditions, recognize their presentations, and respond quickly and appropriately when presented with these deadly reactions. aej volume 7 no. 1 2019 anesthesia ejournal volume 7 no.1 2019 www.anesthesiaejournal.com page 2 case summary a 47-year-old man with a weight of 101 kg and height of 182.9 cm was scheduled for a modified left atrial maze procedure, coronary bypass of the posterior descending artery, and aortic root replacement with a mechanical aortic valve conduit. the patient had a recently diagnosed history of hypertension, atrial fibrillation, coronary artery disease, nonruptured ascending aortic aneurysm, aortoannular ectasia with severe aortic insufficiency, and hyperlipidemia. the patient was taking metoprolol, furosemide, hydrochlorothiazide, lovastatin, and dabigatran (which had been discontinued for at least 3 days). the results of the patient’s chemistry panel and complete blood count were unremarkable, but hemoglobin and hematocrit values of 11.8 mg/ dl and 35%, respectively, were noted. upon assessment in the preoperative holding area, the patient appeared alert with no signs of distress and a supportive family was present. the results of a physical examination were normal except for an obvious heart murmur and a continuous electrocardiogram displaying atrial fibrillation. after the patient was administered fentanyl 100 mcg intravenous (iv) and midazolam 2 mg iv, a right radial arterial line was placed in the preoperative holding area. the patient was then transported to the operating room, standard monitors were applied, and the arterial line was connected for blood pressure (bp) monitoring. induction of anesthesia was performed with a combination of the inhalational agent sevoflurane and additional administration of midazolam 5 mg, sufentanil 25 mcg, propofol 50 mg, and vecuronium 10 mg iv. the patient was orally intubated with an 8.0-mm endotracheal tube via direct laryngoscopy and the tube was secured at 22 cm at the teeth following confirmation of placement. anesthesia was maintained with sevoflurane at variable end-tidal concentrations along with sufentanil and propofol boluses to maintain a bispectral index monitor reading of 40 to 60 while maintaining systolic bp (sbp) at a desirable value of 90 to 110 mm hg for the indicated procedures. after induction, a right subclavian central line and right internal jugular pulmonary artery catheter with a sheath introducer were placed. the pulmonary artery catheter revealed a pulmonary artery pressure of 32/22 mm hg, central venous pressure of 16 mm hg, cardiac output of 5.5 l/min, cardiac index of 2.5 l/min/m2, and a mixed venous oxygen saturation (svo2) of 68%. cefuroxime 1.5 g iv was administered for infection prophylaxis. aminocaproic acid 10 g iv bolus was given prior to incision and an additional 5 g was administered over 5 hours during the procedure. the other medication infusions administered were dexmedetomidine 0.3 mcg/kg/h and milrinone 0.375 mcg/kg/min. the procedure proceeded in the usual fashion for patients undergoing coronary artery bypass with endoscopic vein harvest, save for the time taken to perform the maze procedure. the precpb period was uneventful. minimal boluses of phenylephrine 100 mcg and ephedrine 5 mg iv were given to maintain sbp at 90 to 110 mm hg. cpb was initiated approximately 60 min after incision. total cpb time was 4 hours. the aortic valve and root were replaced along with the graft bypassing the posterior descending coronary artery. the patient received 4 units of packed red blood cells while on cpb. as rewarming began, norepinephrine was started at 0.04 mcg/kg/min. when the primary aortic cross-clamp was removed, lidocaine 100 mg iv was given along with calcium chloride (cacl) 500 mg iv. albumin 5% 500 ml was given prior to cessation of cpb. after successful weaning from cpb and transesophageal echocardiography revealed satisfactory improvement of forward flow of blood through the mitral and aortic valves, protamine sulfate 500 mg iv was infused over 10 min with close hemodynamic monitoring. after the protamine had finished infusing, 2 units of fresh frozen plasma and 1 unit of platelets were infused. during the time of cpb weaning, crystalloids were given more liberally owing to inadequate filling of the heart. the total volume of crystalloid was approximately 2.3 l at 5 hours from the start of the case. the patient was hemodynamically stable after complete weaning from cpb and in sinus rhythm with a heart rate of 83, bp in the 90s/60s mm hg, cardiac output of 5.1 l/min, cardiac index of 2.3 l/min/m2, pulmonary artery pressure of 48/34 mm hg, central venous pressure of 30 mm hg, and svo2 of 63%. forty-five minutes after weaning from cpb and 30 minutes after infusion of the platelets and fresh frozen plasma, the patient’s oxygen saturation as measured by pulse oximetry (spo2) was trending into the low 90s and upper 80s but responded to large manual breaths and was initially thought to be due to atelectasis. as time progressed, however, the patient’s spo2 continued to decrease with a concomitant decrease in end-tidal co2 to approximately 20 mm hg. the initial diagnosis included a possible pulmonary embolus or clot resulting in obstructed gas exchange. an arterial blood gas sample revealed a partial pressure of oxygen (pao2) of 53 mm hg (despite 100% fio2 [fraction of inspired oxygen]), ph 7.24, and arterial oxygen saturation (sao2) of 83%. it was almost accepted that an embolus was the precipitating factor owing to adequate tidal volumes, normal airway pressures, and transesophageal echocardiography (tee) revealing significant improvement in cardiac function. a chest x-ray revealed pulmonary infiltrates versus effusion on the right side. the sternum was reopened for inspection and a pleural chest tube was placed. at 80 minutes post-cpb time, mucus was present in the heat and moisture exchange filter where the endotracheal tube (ett) connects to the breathing circuit. in-line suctioning of the ett produced copious amounts of fluid that totaled a volume of 400 ml plus the large amount that spilled onto the floor and onto towels. fiberoptic bronchoscopy revealed a lake of fluid. suctioning with the bronchoscope was performed and an additional 600 ml was removed. however, the lungs filled back up with fluid almost as fast as the fluid was aspirated. furosemide 20 mg iv was given but failed to improve the situation. the patient’s bp began to wane despite a high number of phenylephrine boluses equalling 5 mg over about 1 hour, a norepinephrine infusion at 0.5 mcg/kg/min, plus the addition of epinephrine at 0.02 mcg/kg/min. dexmedetomidine was discontinued. the surgeon, anesthesia team, and intensivist all agreed that all resuscitation measures had been taken; there was nothing more to do. the patient was transported to the intensive care unit 8 hours after the surgery began and was pronounced dead 30 minutes after arrival. postoperative laboratory values were unremarkable aside from the arterial blood gas and slightly elevated coagulation values, prothrombin time of 22.2, partial thromboplastin time of 44, and international normalized ratio anesthesia ejournal volume 7 no. 1 2019 www.anesthesiaejournal.com page 3 of 1.9. the patient received a total of 3500 ml of crystalloids, 4 units of packed red blood cells, 2 units of fresh frozen plasma, 500 ml of 5% albumin, and 1 unit of platelets. urinary output was 1400 ml and estimated blood loss was 795 ml. discussion the initial consideration was that the patient had developed a pulmonary embolus. the patient was in atrial fibrillation before the case and up to the time of the maze procedure. dabigatran had been discontinued for at least 3 days before surgery, leading to the possibility of clot formation. the physician’s assistant noted the presence of clots during the endoscopic vein harvest of both legs. the low spo2, low end-tidal carbon dioxide (etco2), and hemodynamics requiring vasopressor support lent credence to a diagnosis of a pulmonary embolus. however, no pulmonary embolus was detected by tee. a pulmonary embolus was ruled out after manifestation of fulminant pulmonary edema. other possibilities considered were trali or a severe reaction to protamine sulfate. furosemide was administered, although it did little, if anything, to relieve the pulmonary edema. despite almost continuous suctioning of the airway via the fiberoptic bronchoscope, fluid continued to fill the lungs. the only viable option at this point for resuscitation was extra-corporeal membrane oxygenation (ecmo). unfortunately, ecmo was not available at the facility or in the local community. the exact cause of the devastating event was unknown. the presentation supported trali and a severe reaction to protamine as the culprit. further investigation was required to identify the cause. an acute lung injury occurring during or within 6 hours of the administration of blood products defines the rare and often deadly trali.1 several signs may be observed as this process occurs, such as dyspnea, hypoxia, hypotension, pulmonary hypertension, pulmonary edema, pulmonary infiltrates on chest x-ray, and decreased lung compliance.2 the ali is noncardiogenic in nature and occurs without the presence of circulatory overload.3 all of the aforementioned signs were part of the clinical picture for the patient in this case except for the decrease in lung compliance. however, it has been suggested that there is a time gap between the development of pulmonary hypertension and a decrease in lung compliance.2 the length of that time gap may be patient-dependent. because this patient died about 3 hours after the administration of the blood products, the decreased compliance may not have manifested before transport from the operating room. the complete pathophysiology of trali is unknown but is likely precipitated by leukocyte antibodies or the activation of inflammatory mediators that can result in increased pulmonary capillary permeability and ultimately poor pulmonary function.1 the treatment for trali is primarily supportive with the primary goal of discontinuing administration of the insulting blood products if possible. some evidence suggests that the use of steroids may be of benefit.1 in the case of this patient, the devastating toll that the pulmonary edema caused could only be treated with ecmo. unfortunately, ecmo was not available at this facility or within the local community. some studies have presented evidence for increased risk factors linked to trali, such as higher interleukin-8 levels, elevated peak airway pressures during mechanical ventilation, smoking, and a positive fluid balance.3 a severe reaction to protamine sulfate is a second possible cause of the fulminant pulmonary edema and cardiovascular collapse. there are 3 types of reactions to protamine classified as type i, type ii, and type iii. the type iii reaction is the most severe and exerts its profound effects by the formation of large heparin-protamine complexes that accumulate in the pulmonary circulation. this leads to the release of chemical mediators, a profound decrease in bp, and an elevation in pulmonary artery pressures that can ultimately lead to right ventricular failure.4 documented cases of noncardiogenic, fulminant pulmonary edema after the administration of protamine are published.5,6 one case report describes a reduction in oxygen saturation and pink, frothy sputum suctioned from the ett immediately after the administration of protamine.6 a second case report describes the same presentation but was unable to state with confidence whether the triggering agent was blood products or protamine.5 the release of endothelial nitric oxide and histamine with mast cell degranulation due to rapid infusion of protamine has been suggested as the process for protamine reactions.4 primary risk factors for protamine reactions include rapid infusion, prior exposure, history of vasectomy, impaired left ventricular function, and hemodynamic instability.7 during the slow administration of protamine to the patient in the present case, no hemodynamic instability was noted. the evidence suggests that slowing the infusion rate of protamine when hypotension is encountered is often enough to eliminate symptoms. however, in the case of severe type iii reactions, it may be necessary to re-heparinize and resume cpb until stable by reducing the heparin-protamine complex size.4 furthermore, if a patient has a known sensitivity to protamine or has had prior exposure, an alternative anticoagulant agent may be necessary.4 conclusion noncardiogenic pulmonary edema after cpb can be deadly. treatment to restore effective gas exchange and restore hemodynamic stability is difficult and multifaceted. in retrospect, prompt determination of differential diagnoses and treatment involving the surgical, anesthesia, and perfusion teams to resume cpb may have changed the outcome in the present case. there was no definitive diagnosis of trali vs type iii protamine reaction for this patient. anesthesia professionals must know the risk factors for trali and protamine reactions, identify onset promptly, and initiate treatment immediately. anesthesia ejournal volume 7 no. 1 2019 www.anesthesiaejournal.com page 4 references 1. bitargil m, arslan c, basbug hs, et al. transfusion-related acute lung injury following coronary artery bypass graft surgery. perfusion. 2015;30(8):626-628. pmid:25575703. 2. kojima t, nishisako r, sato h. a patient with possible trali who developed pulmonary hypertensive crisis and acute pulmonary edema during cardiac surgery. j anesth. 2012;26:460-463. pmid:22249282. 3. miller rd. patient blood management: transfusion therapy. in: miller rd, ed. miller’s anesthesia. 8th ed. philadelphia, pa: elsevier; 2015:1830-1867. 4. nussmeier na, sarwar mf, searles be, et al. anesthesia for cardiac surgical procedures. in: miller rd, ed. miller’s anesthesia. 8th ed. philadelphia, pa: elsevier; 2015:2007-2095. 5. kindler c, bircher a, stulz p. protamine-induced fulminating non-cardiogenic pulmonary edema following cardiopulmonary bypass. eur j cardiothorac surg. 1996;10(6):463-466. pmid:8817145. 6. brooks jc. noncardiogenic pulmonary edema immediately following rapid protamine administration. ann pharmacother. 1999;33(9):927-930. pmid:10492491. 7. kimmel se, sekeres ma, berlin ja, et al. risk factors for clinically important adverse events after protamine administration following cardiopulmonary bypass. j am coll cardiol. 1998;32(7):1916-1922. pmid:9857872. 154-##_other-1035-1-11-20220111.jpg volume 9no. 8 2021 educated hand publishing llc “the science behind the art” volume 9 no.8 2021 anesthesia ejournal online issn 2333-2611 page 15 submental intubation for lefort type iii fracture ashley bumatay, bsn, rn affiliation: texas christian university grant/financial support: none keywords: submental intubation, oral/maxillofacial fractures, lefort type iii fracture abstract this case report describes the use of submental intubation for an open reduction internal fixation (orif) lefort type iii fracture encountered at methodist dallas medical center operating room (or). other airway management options in maxillofacial fractures include nasotracheal intubation or tracheostomy, however, these options come with complications and may be contraindicated in certain cases. submental intubation is an alternative airway route for oral/ maxillofacial surgeries when nasotracheal intubation or tracheostomies are not indicated. while submental intubations are low-risk, low-cost, simpler, and faster, it still comes with complications including minimal scarring. no special equipment is needed. aej volume 8no. 8 2020 educated hand publishing llc “the science behind the art” volume 8 no.8 2020 anesthesia ejournal online issn 2333-2611 page 25 reducing the carbon footprint of the anesthesia provider levi scott mcgowan, dnp, crna keywords: carbon footprint, anesthesia, greenhouse gases, global warming abstract modern anesthesia contributes to environmental pollution with some anesthetics creating a larger carbon footprint. certified registered nurse anesthetists (crna) provided over 45 million anesthetics in 2018, and practice changes could dramatically reduce the carbon footprint. the purpose of this quality improvement project was to provide education to a convenience sample of 10 crnas about concrete measures which reduce the carbon footprint of anesthesia care and provide multiple secondary benefits. results showed that when given additional education about environmentally cleaner anesthetics, the clinicians became more aware of safer and greener alternatives for anesthetic use. the reduced carbon footprint anesthetic is not only better environmentally but is also safer and leads to improved patient satisfaction by reducing postoperative nausea and vomiting. aej educated hand publishing llc “the science behind the art” volume 8 no.8 2020 anesthesia ejournal online issn 2333-2611 page 26 references reducing the carbon footprint of the anesthesia provider levi scott mcgowan, dnp, crna ● to provide awareness in the form of continuing education regarding anesthesia practices that are more environmentally friendly and reduce the carbon footprint utilizing a convenience sample of 12 certified registered nurse anesthetists (crnas). 1. national academy of sciences (u.s.), royal society (great britain). climate change : evidence & causes. washington d.c.: national research council; 2014.accessed june 1, 2020. http://www.nap.edu/catalog.php?record_id=18730. 2. campbell m, pierce jmt. atmospheric science, anaesthesia, and the environment. bja education. 2015;15(4):173-179. doi:10.1093/bjaceaccp/mku033. 3. sherman j, le c, lamers v, eckelman m. life cycle greenhouse gas emissions of anesthetic drugs. anesthesia and analgesia. 2012;114(5):1086-1090. doi:10.1213/ane.0b013e31824f6940. 4. lipana l, credaroli e., sukumar m, dai f, sherman j. surveying knowledge on environmental impact of anesthetic gases using an original mobile application. lecture presented at: anesthesiology; june 2017 session; boston, ma. 5. hall mj, national center for health statistics (u.s.). ambulatory surgery data from hospitals and ambulatory surgery centers: united states, 2010. hyattsville, md: u.s. department of health and human services, centers for disease control and prevention, national center for health statistics 6. zuegge l. ecological and economical practice for anesthesiologists. advances in anesthesia. 2013;31(1): 21-29. 7. gan tj, diemunsch p, habib as, et al. consensus guidelines for the management of postoperative nausea and vomiting. anesth analg. 2014;118(1):85-113. ● data shows world surface temperatures have increased by 0.8ºc (1.4 ºf) since 1900. humans have accelerated the release of large amounts of greenhouse gases into the atmosphere since the industrial revolution. the atmospheric concentrations of co2 has increased by 40% with most accumulation of greenhouse gases occurring after 1970.¹ ● the united states (us) healthcare industry accounts for over 8% of total carbon dioxide emissions.³ ● anesthesia contributes to about 5% percent of the total carbon emissions in healthcare. it has been estimated that the annual effect of all inhalation agents is the equivalent to one coal fired power plant.² ● . according to the cdc in 2010, 48.3 million hospital-based surgical and nonsurgical procedures performed in the us contributed to global warming.⁵ ● a yale study conducted in 2017 concluded there are gaps in knowledge related to the environmental impact of anesthetic practice.⁴ • design: quality improvement project using an educational session to increase awareness on methods to reduce the carbon footprint of anesthesia • setting: community hospital in southeast region of the us • sample population: convenience sample of 12 practicing crnas with an average of xx years of experience • data collection: post education survey data collected in june 2019 • measurements: likert and multiple-choice survey assessed educational sessions’ effectiveness and postsession knowledge • quantitative analysis of survey was performed. results ● 40% (n=10) of participants reported no prior knowledge of anesthesia-related carbon footprint reduction education. ● attendees gained knowledge and selected the correct answers at a statistically significant rate with p values < 0.05 for single correct answer questions. ● climate change opinions of the participants did not statistically change the post educational survey likert questions on carbon footprint reduction based of the mann whitney u test of less than two for statistical noteworthiness. ● according to the post educational survey, 100% of participants agreed carbon footprint and anesthesia selection should be incorporated into future srna curriculum ● curriculum development is needed to educate current and future anesthesia providers about the benefits of greener anesthesia techniques. ● limiting desflurane use can reduce pharmacy costs and lower the environmental impact. ● generic propofol has one of the lowest costs and lowest carbon footprints. ● propofol has secondary benefits such as a 25% reduction in ponv which can reduce patient-related stress and overall healthcare costs.⁷ ● a lower carbon footprint anesthetic can lower pharmacy costs, improve patient satisfaction and reduce anesthetic-related ponv. anesthesia agent & carbon footprint impact purpose conclusions methods background & research $ ● modern-day anesthesia has a variable impact on the environment based off the selected anesthetic. 6 anesthesia ejournal volume 4 issue 1 2016 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 page 26 an institutional perioperative intravenous insulin infusion algorithm: evaluation and recommendations tamra dukatz, msn, crna emma hurst, msn, crna mary golinski, phd, crna solomon rosenblatt, md alla sakharova, md james van loon, ms affiliations: beaumont health in royal oak and oakland university beaumont graduate program of nurse anesthesia keywords: perioperative, insulin, diabetes, glycemic, pump abstract the purpose of this retrospective medical record analysis was to examine our noncardiac surgery insulin infusion algorithm for efficacy, safety, and provider adherence. the sample included 132 hyperglycemic patients who were placed on intravenous insulin infusions (standard group). nineteen patients using insulin pumps at home that had been converted for surgery to intravenous infusions were studied separately (insulin pump group). efficacy, safety, and adherence definitions were developed and the data were extrapolated to address the research purpose. captured data did not reflect any incidences of blood glucose (bg) measurements <50 mg/dl; however, 2 bg measurements in the standard group were <70 mg/dl. in the standard group, 73% of patients achieved bg of 100-179 mg/dl and an 85% mean proportion of subsequent time within range throughout the remaining perioperative period. algorithm adherence metrics were 54-58%. lower time-weighted average bg (190 vs 206 mg/dl; p=0.03) was achieved where providers adhered to the intravenous insulin maintenance table at least 67% of the time. in the insulin pump group, mean proportion of subsequent time within range was 81% after conversion to intravenous infusions. increased insulin algorithm adherence was associated with improved perioperative glycemic control. in the insulin pump group, successful conversion was attributed to glycemic nurse practitioner collaboration and algorithm reference. algorithm modifications based on the study results were proposed to increase adherence and safety. introduction practice guidelines specific to managing hyperand hypoglycemia (glycemic derangements) in the perioperative setting have changed significantly over the past several years. clinical trial findings have identified associations between glycemic control and decreased postoperative morbidity in several noncardiac surgery specialties.1-5 experts have encouraged anesthesia practitioners to develop institutional guidelines for the care of patients with diabetes and to target specific blood glucose values.6 the united kingdom national health service (uknhs) has advocated for a perioperative blood glucose target range of 6-10 mm (108-180 mg/dl) and an acceptable range of 4-12 mm (72-216 mg/dl).7,8 blood glucose values of 150 mg/dl or 180 mg/dl have been recommended for triggering insulin administration by several groups, including the society for ambulatory anesthesia.9-12 hypoglycemia is a potential untoward effect whenever exogenous insulin is administered.13 the risk of hypoglycemia may be greater in the perioperative setting than in other areas in the hospital. signs and symptoms of low blood glucose can be obscured by sedation and anesthesia. blood glucose testing may be postponed during critical points such as airway maneuvers, invasive line insertion, hemodynamic stabilization, and emergence from anesthesia. perioperative units may not have consistent processes in place for transfer of care that ensure continuity of treatment and blood glucose testing. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 27 practice guidelines continue to evolve for monitoring blood glucose and managing glycemic derangements in the perioperative setting.6 insulin administration via intravenous (iv) infusion is the preferred delivery method for patients undergoing major surgeries or surgeries with expected, prolonged postoperative fasting. a desirable perioperative iv insulin infusion guideline efficiently attains and maintains a moderate blood glucose target range while safeguarding against severe hypoglycemia. anesthesia providers may use existing institutional iv insulin infusion algorithms previously developed for intensive care units (icus). however, icu algorithms often offer tighter and more aggressive target ranges than generally considered feasible in the dynamic perioperative setting. a growing number of patients are presenting for surgery with existing insulin pumps [continuous subcutaneous insulin infusions (csii)]. these individuals sometimes warrant conversion to iv insulin infusions owing to postoperative incapacity for pump selfmanagement. successful conversion coordinates the commencement of iv insulin infusion with the lessening effect of the residual subcutaneously delivered insulin, while correcting for hypoglycemia or hyperglycemia. two experts recommend starting the iv insulin infusion at a lower percentage of the usual basal insulin pump rate for blood glucose ≤180 mg/dl and at the usual basal insulin pump rate if >180 mg/dl.14,15 no studies were found on the efficacy of any particular protocol for converting patients from insulin pumps to iv insulin infusions. adoption of a validated iv insulin infusion protocol is advised to promote more consistent glycemic control and favorable surgical patient outcomes. institutional modification to specific inpatient populations may improve adherence and efficacy.16 an existing paper-based algorithm was altered at the beaumont health system, royal oak, michigan, campus to target the 2009 american diabetes association/american college of clinical endocrinologists consensus blood glucose range of 140-179 mg/dl.9 guidelines for conversion from insulin pump therapy (csii) to iv insulin infusions were constructed and incorporated into the algorithm. the purpose of this research was to evaluate this iv insulin infusion algorithm (figure 1) for (1) efficacy, (2) safety, and (3) assessment of practitioner adherence to algorithm dose recommendations and hourly blood glucose monitoring. materials and methods after human investigation committee approval, which included a waiver of authorization for consent, a list was generated by the pharmacy of patients receiving insulin infusion admixtures in perioperative areas between august 2010 and july 2013. the list was narrowed and inclusion criteria for analysis were as follows: • patients who had a noncardiac surgical procedure, • age > 17 years, • nonparturient , • insulin infusion newly initiated in the perioperative setting, and • 3 or more blood glucose tests performed in the perioperative setting after infusion initiation. data were extracted from the medical and anesthesia records by investigators and were entered into an excel (microsoft corp, redmond, wa) spreadsheet. the documented demographic data included hyperglycemia etiology, glucose-lowering medications, perioperative length of stay, surgery length, surgery type, american society of anesthesiologists classification, and anesthesia type. perioperative blood glucose values after infusion initiation, blood glucose test times, and first blood glucose value on arrival in the postoperative nursing care unit were collected. operational definitions used to assist the research purpose were developed. efficacy was determined by both achievement of a blood glucose value <180 mg/dl and maintenance of subsequent blood glucose values in the 100-179 mg/dl target range. maintenance in the target range was measured by the proportion of time that blood glucose values remained in the 100-179 mg/ dl range from the first value <180 mg/dl to the last perioperative value before post-anesthesia care unit discharge. additionally, the time from the initiation figure 1. perioperative insulin infusion algorithm for use in adult cases, except cardiac surgery (target blood glucose: 140-179 mg/dl) anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 28 table 1. baseline characteristics of the two study groups standard group (n=132) insulin pump group (n=19) age, years 63.5 ± 11 56.3 ± 13 gender (% male) 51.5 52.6 body mass index, kg/m2 33.4 ± 9 31.8 ± 7 hyperglycemia etiology, % type 1 diabetes 6.8 57.9 type 2 diabetes 87.9 42.1 steroid-induced hyperglycemia 4.5 0 pancreatic pseudocyst 0.8 0 diabetes regimen, % insulin with/without other glucose-lowering agents 62.8 100 glucose-lowering agents (without insulin) 29.8 0 no glucose-lowering agents 7.4 0 asa classification status, % 2 18.9 31.6 3 65.9 68.4 4 15.2 0 anesthesia type, % general 88.6 94.7 regional 3.8 5.3 sedation 7.6 0 surgical procedure length, hours 4.3 ± 3 2.2 ± 1 perioperative length of stay, hours 9.7 ± 3 7.1 ± 1 postoperative icu admission, % 14.4 0 surgical service, % general (including bariatric and pancreatic) 34.1 21.1 vascular 17.4 0 neurosurgery (not spine) 15.2 0 orthopedic (not spine) 8.3 21.1 spine 7.6 26.3 other (urology, gynecology, thoracic, combined cases) 17.4 31.5 mean bg before insulin infusion initiation, mg/dl 266.5 ± 75 189.8 ± 73 median bg before insulin infusion initiation, mg/dl 255 173 area of infusion initiation, % (bg before initiation) preoperative area (mean bg; mg/dl) 28 (319.3) 63.2 (212.8) operating room (mean bg; mg/dl) 70.5 (246.3) 36.8 (150.3) post-anesthesia care unit (mean bg; mg/dl) 1.5 (229.0) 0 number of bg tests performed 5.5 ± 1.2 5.5 ± 1.8 note. abbreviations: asa, american society of anesthesiologists; bg, blood glucose; icu, intensive care unit. values are mean ± sd, unless otherwise indicated. of insulin infusion to achievement of blood glucose target and the average perioperative blood glucose values after infusion initiation were recorded. safety was defined as avoidance of hypoglycemia (blood glucose <70 mg/ dl) and severe hypoglycemia (blood glucose <50 mg/dl). the highest rate of insulin infusion, the presence of iv dextrose initiation, and the occurrence of insulin infusion discontinuation, either temporarily or permanently during the perioperative time frame, were documented. practitioner adherence to algorithm dose recommendations was defined as compliance with algorithm directives for insulin infusion initiation and titration. for infusion initiation, the algorithm’s initiating infusion table, shown as (1) in figure 1, details standard group initiation directives, while the insulin pump patients directives at the bottom of the algorithm state the insulin pump group directives. for infusion titration, the algorithm’s (2) titrating infusion table and (3) calculation chart direct infusion titration and insulin bolus administration for both the standard group and the insulin pump group. insulin administration that did not comply with the initiation and titration tables was examined for type of deviation. practitioner adherence to glucose monitoring frequency was defined as the occurrence of extended intervals between blood glucose testing. a lapse of more than 30 minutes beyond the hourly recommended blood glucose monitoring frequency was designated as an extended interval. the data from each individual medical record were entered into spreadsheets and 2 different groups were identified: (1) the insulin pump group or those whose outpatient glycemic control was managed by an existing insulin pump, and (2) the standard group, or the remainder of the cohort. statistical analyses side-by-side descriptive analyses were performed. continuous variables were summarized by using means ± standard deviations, unless otherwise noted. categorical variables were summarized by using frequencies anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 29 table 2. efficacy, safety, and compliance results standard group (n=132) insulin pump group (n=19) efficacy patients in which infusion was initiated at bg* < 180 mg/dl, % 4.5 57.9 patients achieving bg < 180 mg/dl after infusion initiation, % 72.7 26.3 mean time to achieving bg < 180 mg/dl, hours 2.4 1.2 mean proportion subsequent time in algorithm target 0.639 0.428 mean proportion subsequent time in perioperative target 0.849 0.808 mean twa of perioperative bg after initiation, mg/dl 200.9 ± 42 168.0 ± 41 median twa of perioperative bg after initiation, mg/dl 194.1 156.6 mean twa bg above target range, mg/dla 33.6 14.8 median twa bg above target range, mg/dla 23.9 2.3 mean twa bg of area out of perioperative target, mg/dl 33.9 15.3 median twa bg of area out of perioperative target, mg/dl 23.9 4.5 mean bg on postoperative nursing unit arrival, mg/dl 171.7 ± 54 179.3 ± 51 median bg on postoperative nursing unit arrival, mg/dl 164 174 safety patients with any bg < 70 mg/dl during infusion, % 1.5 0 patients with any bg < 50 mg/dl during infusion, % 0 0 adherence infusion initiation adhered with algorithm initiation table, % 53.8 57.9 infusion maintenance adhered with algorithm tables, % total bg 55.6 54.9 mean interval between bg tests, minutes 59.7 ± 10 52.9 ± 8 note. abbreviations: bg, blood glucose; twa, time-weighted average. algorithm target = 140-179 mg/dl; broader perioperative target = 100-179 mg/dl. values are mean ± sd, unless otherwise indicated. *hyperglycemic index measurements; total bg = tests for all patients in group (700 bg tests in standard group; 102 bg tests in insulin pump group). and percentages. estimated time-to-target was calculated via a straight-line interpolation between blood glucose levels at successive measured time points. proportion of subsequent time spent within range after target achievement—again using the interpolation method—was measured per subject for both the narrower algorithm target and the broader perioperative target. time-weighted average (twa) area under the curve blood glucose was calculated per subject from all blood glucose values from the first test after infusion initiation to the last perioperative area test. twa area out of target was calculated per subject from all blood glucose values <100 mg/dl and >179 mg/dl from the first test after the infusion initiation to the last perioperative test. hyperglycemic index, which addressed only twa area above target (blood glucose >179 mg/dl), was also examined. results inclusion criteria were met for 151 of 456 accessed records. cases of cardiac surgery (n=192) and fewer than 3 perioperative blood glucose tests after infusion initiation (n=98) were excluded. there were 132 patients in the standard group and 19 patients in the insulin pump group. the baseline characteristics of the 2 groups are shown in table 1. efficacy, safety, and adherence metrics are displayed in table 2. in both groups, nearly 80% of patients presented with or achieved blood glucose <180 mg/dl before postanesthesia care unit discharge. after the first blood glucose <180 mg/dl, the mean proportion of subsequent time spent in the 100-179 mg/ dl range was >80%. the mean proportion of subsequent time in the algorithm target range (140-179 mg/dl) was 64% (standard group) and 43% (insulin pump group). the mean time to target achievement was <2.5 hours for patients presenting with blood glucose >180 mg/dl. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 30 two patients in the standard group experienced hypoglycemia. the first patient’s blood glucose value of 69 mg/dl was attributed in part to receipt of 10 units of insulin aspart subcutaneously in the perioperative area before the start of the insulin infusion. in the second patient, a blood glucose decline from 167 mg/dl to 83 mg/dl resulted in stopping the infusion; however, the subsequent blood glucose tested 20 minutes later was 53 mg/dl. the second patient’s hypoglycemia occurred despite 100% adherence to algorithm tables and hourly blood glucose monitoring. as a result of this finding, institutional approval was sought and obtained to add the directive of “begin d5w at 75 ml/hr” to the 80-99 mg/ dl cell. the mean highest insulin infusion rates were 4.6 ± 2 units/hour for the standard group and 2.8 ± 1.8 units/hour for the insulin pump group. insulin pump patients (63.2%) and standard patients (32.6%) had concurrent iv dextrose infusions during at least a portion of the time on the iv insulin infusion. in the standard group, 28.8% of patients had the iv insulin infusion permanently stopped before leaving the perioperative area. another 6.8% of the standard group had the infusion temporarily stopped and later restarted. three patients had the insulin infusion permanently discontinued in the insulin pump group while still in the perioperative area. two other insulin pump patients had the infusion stopped and later restarted. practitioner adherence to the algorithm dose recommendations was found to be between 53.8% and 57.9% for both groups (table 2). in the standard group, the deviations at initiation were as follows: wrong/omitted bolus (29.5%), wrong/omitted bolus and wrong rate (13.6%), and wrong rate only (3%). in the insulin pump group, the deviations at initiation were as follows: received a bolus (10.5%), infusion not started at basal rate (10.5%), time interval deviated from guidelines (10.5%), combination of any 2 preceding deviations (10.5%). titration deviations were classified as wrong rate (standard group, 14.4%; insulin pump group, 27.5%), wrong/omitted bolus (standard group, 13.9%; insulin pump group, 2.9%), and wrong rate and wrong/omitted bolus (standard group, 15.7%; insulin pump group, 14.7%). two standard group patients had deviations from recommended hypoglycemia treatment but neither incidence resulted in subsequent hypoglycemia. the mean blood glucose monitoring interval was under 1 hour. in the standard group, 29.5% of patients experienced at least one blood glucose monitoring interval >90 minutes. in the insulin pump group, 30.1% of patients had one or more intervals of >90 minutes between tests. post hoc analyses were performed to determine if there was a relationship between glycemic control and adherence because algorithm deviations were higher than anticipated. the insulin pump group was not examined owing to the small sample. patients in the standard group were split into 2 categories based on the proportion of their adjustments that deviated from the maintenance algorithm: “less than 1/3” (low deviation), and “1/3 and up” (high deviation). a t-test of difference was performed for time to target, mean twa blood glucose, and mean twa area out of target (table 3). closer algorithm adherence was associated with a lower mean twa blood glucose. table 3. comparison of glycemic control in low vs. high deviatorsa from the intravenous insulin infusion algorithm recommendation (standard group only) low deviators (n=44) high deviators (n=88) p valueb time to bg <180 mg/dl, hours 2.0 2.6 0.14 twa perioperative bg after initiation, mg/dl 190.0 206.4 0.03 twa time out of perioperative target, mg/dl 27.1 37.2 0.09 note. abbreviations: bg, blood glucose; twa, time-weighted average. values are means. ahigh deviators had one-third or more deviations in intravenous insulin titrations from the algorithm recommendations; low deviators had less than one-third deviation from the algorithm. bt-test of differences. discussion the intent of this research was to critically evaluate the performance of beaumont health’s perioperative paper-based iv insulin infusion algorithm with incorporated insulin pump (csii) conversion directives. this algorithm is believed to be an efficacious option for use in noncardiac surgery patients. the investigators cautiously offer this conclusion because about 55% of insulin administration across all patients adhered with algorithm recommendations and 30% of patients experienced at least one glucose monitoring interval of greater than 90 minutes. in post hoc analyses, increased algorithm adherence was associated with improved perioperative glycemic control. the insulin pump conversion directives avoided severe hypoand hyperglycemia. the standard group even with suboptimal adherence and monitoring lapses, over 70% of patients achieved the target and 85% of the subsequent time was spent in the glycemic target range of 100-179 mg/dl. there was a progressive gradual decline in median blood glucose values from the one at the initiation of insulin infusion to the first postoperative nursing unit value (255 mg/dl to 194.1 mg/ dl to 164 mg/dl). a median hyperglycemic index of 23.9 mg/ anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 31 dl indicates that despite blood glucose excursions, most patients remained within the 72-216 mg/dl wider uknhs glycemic target range. this algorithm’s moderate target range (140-179 mg/dl), preemptive downward titration, and early discontinuance of the insulin infusion likely contributed to the low rate of hypoglycemia. one of two hypoglycemic incidences was mild and was associated with a residual insulin effect from a prior subcutaneous insulin injection. circumstances surrounding the other incidence of moderate hypoglycemia (53 mg/dl) exposed a weakness in the algorithm. with the decline in blood glucose from 167 to 83 mg/dl, initiation of an iv dextrose 5% infusion in addition to turning off the insulin infusion at the 83 mg/dl value may have prevented the subsequent blood glucose of 53 mg/dl. as a result of this study, beaumont health has since revised the algorithm to include “begin d5w at 75 ml/hr” in addition to stopping the infusion for any blood glucose in the 80-99 mg/dl range. neither glycemic targets nor glucometrics for perioperative settings have been unequivocally established. this iv insulin infusion algorithm targets the 140-179 mg/dl range. beaumont health’s perioperative blood glucose acceptable range (100-179 mg/dl) for all patients with diabetes is similar to the uknhs 108-180 mg/dl recommended range.7,8 the metrics in this study (time-to-target, subsequent time within target, twa blood glucose, and hyperglycemic index) have been most often used in nonperioperative hospital settings and over longer time periods. the investigators found only one other study that presented metrics validating a paper-based iv insulin infusion protocol during the perioperative period in noncardiac surgery patients. abdelmalak et al17 examined subjects who had been randomly assigned for the delit clinical trial. similar to this study , the abdelmalak algorithm was based on blood glucose trend and incorporated iv insulin boluses and infusion rate increases to treat hyperglycemia. unlike this study, the abdelmalak algorithm had a lower, narrower blood glucose target (80-110 mg/dl) and higher blood glucose monitoring frequency (every 30 minutes). also, the abdelmalak sample had a lower mean preoperative blood glucose (118 mg/dl) and lower percentage of subjects with diabetes (28%). abdelmalak et al concluded that their algorithm was efficacious, with minimal resulting hypoglycemia. glucometric comparison between studies is difficult because of differences in algorithm target ranges. the investigators concede that this algorithm is moderately complex with 3 tabular components and adjunctive iv insulin boluses. complex algorithms that require multiple steps and calculations have been found to have high rates of error.18,19 practitioners frequently omitted the adjunctive insulin boluses recommended with the rate increases in the calculation chart [see (3) in figure 1]. lack of insulin boluses may have been due to failure to note the asterisk in the cell, which referred to rate and bolus instructions in the calculation chart. as a result of this finding, the words “and bolus” have replaced the asterisk in each algorithm titration cell where an increase in infusion rate is recommended. additionally, with this retrospective review, the investigators could not ascertain if a given algorithm deviation was purposeful. anesthesia practitioners had the latitude to deviate from the algorithm, whereas preoperative and postanesthesia care nurses should only have deviated by a physician or nurse practitioner order. atypical fractional infusion rate adjustments led us to believe an older institutional algorithm version had been erroneously used in 5 cases. the insulin pump group in this study of 19 insulin pump patients, glycemic control was primarily attained or maintained during conversion, without any hypoglycemic events. glycemic nurse practitioners collaborated with anesthesia providers, surgeons, and endocrinologists for management of insulin pump patients at this institution. strict adherence to the insulin pump directives, without clinical judgment of glycemic nurse practitioners, may or may not yield similar results. these conversion directives resulted in no severe glycemic derangements. two theoretical concerns were identified when this algorithm’s titrating infusion and calculation chart were used for insulin pump patients. first, because the algorithm target was 140-179 mg/dl, the algorithm did not direct upward titration of the infusion until the blood glucose reached >179 mg/dl. most insulin pump patients had type 1 diabetes and thus would have inherently become at increased risk for diabetic ketoacidosis as blood glucose approached 250 mg/dl. earlier intervention to abate a steady rise in blood glucose seemed warranted for this population. second, at the other end of the spectrum, the algorithm twice directed titration off of the insulin infusion at blood glucose values of 80-99 mg/dl. in patients with absolute insulin deficiency, preserving the infusion at the basal rate with concurrent iv dextrose 5% infusion administration seemed to be more appropriate. these observations suggest that a separate iv insulin infusion algorithm for insulin pump patients would be advantageous. study limitations this was a single-institution, retrospective review using a convenience sample. the sample for the insulin pump conversion group was small. nova stat strip (nova biomedical corporation, waltham, ma), the predominant instrument for blood glucose measurement, was a point-of-care testing device, which has less accuracy than hospital laboratory testing devices.20 some infusions were temporarily or permanently discontinued during the perioperative time; however, for simplicity, our analyses included all subsequent blood glucose tests from the infusion initiation until discharge from the perioperative area. in post hoc analyses, improved glycemic control was associated with higher compliance. whether lack of adherence caused worse glycemic control or whether providers tended to deviate more on the harder-to-control patients was impossible to say. strong conclusions from these post hoc results were not possible because the study was purely based on chart review and the choice of a one-third deviation as a cutoff point for “low deviators” was arbitrary. a survey examining clarity and general satisfaction with the algorithm among nurses and nurse anesthetists could perhaps illuminate the findings on adherence. paper algorithms, such as the one evaluated in this study, may have a limited future. computer-based algorithms have consistently demonstrated improved glycemic control with minimal hypoglycemia over paper-based algorithms.21-25 commercial software integrates or interfaces to the electronic medical record and guides the practitioner in initiation and titration of the iv insulin infusion. software features include the ability to individualize care on the basis of underlying patient characteristics and glycemic trend. audible reminders are incorporated for blood glucose monitoring, which is performed by health care providers. although no reports were yet found evaluating the computer-based algorithms to paper-based algorithms in the perioperative setting, the software is approved for use and available in some institutions during surgery. newer concept closed-loop iv insulin delivery systems consist of totally automated dual infusions of dextrose and insulin based on continuous venous or subcutaneous glucose measurements.1,26,27 the closed-loop systems are not currently retailed in the united states. refinement of new technologies and overcoming obstacles for translation into practice should be the focus of future studies. conclusions this beaumont health algorithm generally provided appropriate directives in initiation and maintenance of iv insulin infusions in the noncardiac surgery perioperative setting. in 132 patients presenting with a median blood glucose of 255 mg/dl, 73% attained the goal of <180 mg/dl while in the perioperative area. after goal achievement, the blood glucose values were in the 100-179 mg/dl target range for an 85% mean proportion of time. one incidence of moderate hypoglycemia (53 mg/dl) and one incidence of mild hypoglycemia (69 mg/dl) occurred. patients were safely converted from insulin pumps to iv insulin infusions. there were no incidences of hypoglycemia (<70 mg/dl). of the 19 insulin pump patients, 58% arrived in the preoperative area with blood glucose values <180 mg/dl, whereas another 26% achieved values <180 mg/dl after the commencement of the iv insulin infusion. for these patients, the 100-179 mg/dl blood glucose range was maintained a mean 80% of the subsequent time. further research is needed to elucidate the ideal pathway when transitioning between subcutaneous insulin pump delivery and iv insulin infusion. low algorithm adherence (approximately 55%) was the study’s main limitation. to further examine efficacy, our post hoc analysis demonstrated improved glycemic control in patients where twothirds or more of algorithm directives were followed. the effect of glycemic nurse practitioner collaboration in managing the insulin pump conversions makes it difficult to generalize results to anesthesia departments without this support. as a result of this project, 2 proposed algorithm changes were implemented at beaumont health. both are editions to the titrating infusion table in figure 1. first, iv insulin boluses in the calculation chart had often been omitted. these omissions were likely due to failure of the provider to note the asterisk directive in the titrating infusion table. cell asterisks have been replaced by the words “and bolus” for better clarity. second, a patient experienced a blood glucose value of 53 mg/ dl 20 minutes after the discontinuance of the insulin infusion for a blood glucose of 83 mg/dl. the commencement of a d5w infusion in addition to discontinuing the insulin infusion would likely have abated this decline to hypoglycemia. “stop infusion and begin d5w at 75 cc/hr; recheck bg in 15-30 minutes” has replaced “hold, recheck bg in 15-30 minutes” in the bg 80-99 mg/dl range cell. summary of key points • paper-based institutional iv insulin infusion algorithms, derived primarily for intensive care settings, are believed to be commonly used for perioperative glycemic management. • an evaluation was done of this beaumont health algorithm (figure 1), which targets the 140-179 mg/dl blood glucose range, employs adjunctive insulin boluses, and aims for aggressive prevention of hypoglycemia. accompanying directives for conversion from continuous subcutaneous insulin infusion (insulin pump) to the iv insulin infusion were also examined. • glycemic control was generally attained and maintained with use of this algorithm, and no severe hypoglycemia occurred. • algorithm adherence was lower than anticipated. the investigators believe that some deviations were intentional clinical judgments and others were errors. post hoc findings seem to indicate improved glycemic control with greater algorithm adherence. • two revisions have been incorporated into the algorithm. the first edition more clearly demonstrates when insulin boluses are indicated and the second directs use of dextrose 5% infusion with any blood glucose <99 mg/dl. references 1. okabayashi t, shima y, sumiyoshi t, et al. intensive versus intermediate glucose control in surgical intensive-care unit patients. diabetes care. 2014;37(6):1516-1524. http://dx.doi.org/10.2337/dc13-1771. 2. umpierrez ge, smiley d, jacobs s, et al. randomized study of basal-bolus insulin therapy in inpatient management of patients with type 2 diabetes undergoing general surgery (rabbit 2 surgery). diabetes care. 2011;34(2):256-261. http://dx.doi. org/10.2337/dc10-1407. 3. subramaniam b, panzica pj, novack v, et al. continuous perioperative insulin infusion decreases major cardiovascular events in patients undergoing vascular surgery: a prospective, randomized trial. anesthesiology. 2009;110(5):970-977. http://dx.doi. org/10.1097/aln.0b013e3181a1005b. 4. king jt, goulet jl, perkal mf, rosenthal ra. glycemic control and infections in patients with diabetes undergoing noncardiac surgery. ann surg. 2011;253(1):158-165. http://dx.doi.org/10.1097/sla.0b013e3181f9bb3a. 5. alexander jw, solomkin js, edwards mj. updated recommendations for control of surgical site infections. ann surg. 2011;253(6):1082-1093. http://dx.doi.org/10.1097/sla.0b013e31821175f8. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 32 6. alexanian sm, mcdonnell, me, akhtar s. creating a perioperative glycemic control program [published online september 6, 2011]. anesthesiol res pract. http://www.ncbi.nlm.nih.gov/pmc/articles/pmc3168770/. accessed january 28, 2016. 7. dhatariya k, levy n, kilvert a, et al; for the joint british diabetes societies. nhs diabetes guideline for the perioperative management of the adult patient with diabetes. diabet med. 2012;29(4):420-433. http://dx.doi.org/10.1111/j.14645491.2012.03582.x. 8. sebranek jj, kopp lugli a, coursin db. glycaemic control in the perioperative period. br j anaesth. 2013;111(51)(suppl 1):i18-i34. http://dx.doi.org/10.1093/bja/aet381. 9. moghissi e, korytkowski m, dinardo m, et al. american association of clinical endocrinologists and american diabetes association consensus statement on inpatient glycemic control. endocr pract. 2009;15(4):353-369. http://dx.doi.org/10.4158/ ep09102.ra. 10. akhtar s, barash p, inzucchi s. scientific principles and clinical implications of perioperative glucose regulation and control. anesth analg. 2010;110(2):478-497. http://dx.doi.org/10.1213/ane.0b013e3181c6be63. 11. joshi gp, chung f, vann ma, et al. society for ambulatory anesthesia consensus statement on perioperative blood glucose management in diabetic patients undergoing ambulatory surgery. anesth analg. 2010;111(6):1378-1387. http://dx.doi. org/10.1213/ane.0b013e3181f9c288. 12. jacobi j, bircher n, krinsley j, et al. guidelines for the use of an insulin infusion for the management of hyperglycemic in critically ill patients. crit care med. 2012;40(12):3251-3276. http://dx.doi.org/10.1097/ccm.0b013e3182653269. 13. curkendall s, natoli j, alexander c, nathanson b, haidar t, dubois r. economic and clinical impact of inpatient diabetic hypoglycemia. endocr pract. 2009;15(4):302-312. http://dx.doi.org/10.4158/ep08343.or. 14. houlden rl, moore s. in-hospital management of adults using insulin pump therapy. can j diabetes. 2014;38(2):126-133. http:// dx.doi.org/10.1016/j.jcjd.2014.01.011. 15. abdelmalak b, ibrahim m, yared j-p, beth modic m, nasr c. perioperative glycemic management in insulin pump patients undergoing noncardiac surgery. curr pharm des. 2012;18(38):6204-6214. http://dx.doi.org/10.2174/138161212803832371. 16. krikorian a, ismail-beigi f, moghissi e. comparisons of different insulin infusion protocols: a review of recent literature. curr opin clin nutr metab care. 2010;13(2):198-204. http://dx.doi.org/10.1097/mco.0b013e32833571db. 17. abdelmalak b, maheshwari a, kovaci bj, et al. validation of the delit trial intravenous insulin infusion algorithm for intaoperative glucose control in noncardiac surgery: a randomized controlled trial. can j anesth. 2011;58(7):606-616. http://dx.doi. org/10.1007/s12630-011-9509-3. 18. cyrus rm, szumita pm, greenwood bc, pendergrass m. evaluation of compliance with a paper-based, multiplication-factor, intravenous insulin protocol. ann pharmacother. 2009;43(9):1413-1418. http://dx.doi.org/10.1345/aph.1m060. 19. magee mc. improving iv insulin administration in a community hospital [published online june 11, 2012]. j vis exp. 2012;(64):3705. http://www.ncbi.nlm.nih.gov/pmc/articles/pmc3476387/. accessed january 28, 2016. 20. scott mg, bruns de, boyd jc, sacks db. tight glucose control in the intensive care unit: are glucose meters up to the task? clin chem. 2009;55(1):18-20. http://dx.doi.org/10.1373/clinchem.2008.117291. 21. horibe m, nair b, yurina g, neradilek mb, rozet i. a novel computerized fading memory algorithm for glycemic control in postoperative surgical patients. anesth analg. 2012;115(3):580-587. 22. juneja r, roudebush cp, nasraway sa, et al. computerized intensive insulin dosing can mitigate hypoglycemia and achieve tight glycemic control when glucose measurement is performed frequently and on time [published online october 12, 2009]. crit care med. http://www.ncbi.nlm.nih.gov/pmc/articles/pmc2784393/. accessed january 28, 2016. 23. fogel sl, baker cc. effects of computerized decision support systems on blood glucose regulation in critically ill surgical patients. j am coll surg. 2013;216(4):828-833. http://dx.doi.org/10.1016/j.jamcollsurg.2012.12.015. 24. newton ca, smiley d, bode bw, et al. a comparison study of continuous insulin infusion protocols in the medical intensive care unit: computer-guided vs. standard column-based algorithms. j hosp med. 2010;5(8):432-437. http://dx.doi.org/10.1002/jhm.816. 25. marvin mr, inzucchi se, besterman bj. computerization of the yale insulin infusion protocol and potential insights into causes of hypoglycemia with intravenous insulin. diabetes technol ther. 2013;15(3):246-252. http://dx.doi.org/10.1089/dia.2012.0277. 26. leelarathna l, english sw, thabit h, et al. feasibility of fully automated closed-loop glucose control using continuous subcutaneous glucose measurements in critical illness: a randomized controlled trial. crit care. 2013;17(4):r159. http://dx.doi. org/10.1186/cc12838. 27. okada t, kawahito s, mita n, et al. usefulness of continuous blood glucose monitoring and control for patients undergoing liver transplantation. j med invest. 2013;60(3.4):205-212. http://dx.doi.org/10.2152/jmi.60.205. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 33 volume 6 no. 5 2018 educated hand publishing llc “the science behind the art” volume 6 no. 5 2018 anesthesia ejournal online issn 2333-2611 page 22 discovery of a pectoral nerve neuroma by procedural ultrasound before breast reconstruction surgery: case report jonathan p kline, msna, crna affiliation: director of education for twin oaks anesthesia. practices independently in office-based plastic surgery and in care team models in southwest florida. adjunct faculty at the simulation based academic fellowship in advanced pain management at the university of south florida funding/conflict of interest disclosure: none keywords: breast reconstruction, chronic pain, neuroma, ultrasound introduction breast reconstructions with multiple variations are commonly performed in the united states. according to the american society of plastic surgeons, breast reconstruction accounted for over 100,000 procedures in 2016 or nearly 2% of all reconstructive procedures.1 steady growth of 39% in breast reconstruction has been reported since 2000 with a 3% increase since 2015. one complication from breast implant placement of nearly any kind is the development of chronic pain, defined as prolonged pain for more than 30 days after surgery. ivica and colleagues reported the incidence of chronic pain after simple breast augmentation at 15%.2 brummett reports that the prevalence of chronic pain after noncosmetic breast surgery is between 29% and 47%, with up to 13% of those patients experiencing severe pain.3 ultrasound is being used in novel ways across the anesthesia community for needle-guided techniques, and increasingly, for bedside diagnosis and treatment. multiple disciplines have produced articles inviting anesthesia providers to incorporate ultrasound for procedures such as the fast (focused assessment with sonography in trauma) examination, bedside transthoracic echocardiography, diagnosis of pneumothorax, and other modalities. this case report describes a patient in which preprocedural ultrasound was used to correctly identify a pectoral neuroma during the routine placement of regional blockade, with subsequent surgical exposure and debulking. abstract chronic pain from breast surgery seems to be commensurate with and increase the number of breast surgeries. many improvements have been made in both surgery and anesthesia techniques. these novel techniques have shown promising results in decreasing postoperative pain and opioid use, along with the cascade of undesirable side effects, and even cancer recurrence. ultrasound may have played an integral part in the development of these analgesic techniques and can further our understanding of relevant anatomy. in the present case, ultrasound was used during the preprocedural analgesia to correctly identify a chronic-pain-causing neuroma. the offending neuroma was subsequently reported to the surgeon before the procedure and was resected under direct vision during the surgical reconstruction. this finding altered the course of the surgery and yielded positive results postoperatively. aej acknowledgment: special thanks to dr wayne, md, for his support with this article anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 5 2018 page 23 review of literature ultrasound is gaining interest as an effective, noninvasive, cost-effective, and certainly convenient point-of-care imaging modality for a variety of purposes. the anesthesia community has embraced its value for needle procedures such as vascular access and regional nerve blocks; however, anesthesia providers are also beginning to appreciate its value for critical care diagnostics, as well as for incidental, but significant, findings. this is reflected in applications similar to the case we present. a pubmed (national library of medicine) search for subject similarity was conducted. mostly case reports currently exist regarding the use of ultrasound for neuroma identification and injection for postamputation pain. additionally, nearly all these articles were reported in journals outside the academic anesthesia community. in 1999 jones and colleagues investigated the feasibility of ultrasound for diagnosing morton’s neuroma with good results.4 in 2003 ernberg and colleagues reported the use of ultrasound in the detection and treatment of a painful stump neuroma.5 in 2011 chen et al presented the use of linear transducer ultrasound for diagnosis and subsequent treatment for postamputation pain.6 a 40-year-old woman presented with postamputation pain and prosthetic intolerance for a below-elbow incident. they successfully identified the median, ulnar, and radial neuromas and injected each with a steroid solution with significant pain reduction. in 2012 torres-claramunt and colleagues reported on the accuracy of ultrasound and magnetic resonance imaging use for diagnosing a morton’s neuroma.7 in 2012, currier and team used ultrasound to detect and treat an ilioinguinal neuroma in a young female presenting with persistent pain in the ilioinguinal/ iliohypogastric nerve distribution.8 an ultrasound examination revealed a swelling of the ilioinguinal nerve, likely from trauma secondary to a pfannenstiel incision. they further used the same imaging to inject the neuroma with 2 ml bupivacaine and steroid on 2 separate occasions. they reported significant reduction in patient discomfort following both injections. in 2016, somashekar et al reported impressive findings related to the use of ultrasound for the diagnosis of brachial plexus neuromas in newborns with brachial plexus palsy.9 in their study, ultrasound imaging correctly identified 21 of 25 cases of upper trunk and middle trunk neuroma involvement with an 84% sensitivity for each. these articles seem to support the notion that ultrasound is being used in novel ways not only to identify and diagnose, but also to provide safe, reliable imaging to direct needle guidance for treatment. case presentation a 29-year-old woman presented to the office-based surgical suite, physical status (ps)) class 2, with significant surgical history, including multiple breast reconstructions and mastectomy. she was currently taking opioid pain medication and occasional muscle relaxant medication to manage lingering left-sided, dull, achy chest wall pain that developed shortly after her previous breast implant surgery and subsequent removal. the removal of the implant was at the patient’s behest owing to pain. however, the removal of the implants did not improve her pain. the procedural plan included ultrasound-guided erector spinae blocks, and novel intrapec injection, followed by general anesthesia with laryngeal mask airway (lma). following the initial discussion, explanation, and approval, the patient gave informed consent for the anesthetic and surgical procedures, including total revision of the breast reconstruction.she was escorted to the operating room table, positioned comfortably prone, sedated with 2 mg intravenous (iv ) midazolam, had monitors placed, and received bilateral ultrasound-guided erector spinae blocks using a terason 3300 paired with a linear probe (12l5; terason-teratech, burlington, ma).the patient was then assisted into the supine position, preoxygenated, and had an uneventful general anesthesia induction and insertion of #3 lma. a linear probe (12l5; terason-teratech) was covered and placed transverse over the anterior lateral chest in preparation for intrapec injection. the right side was performed according to the original description by kline, void of abnormal structures.10 upon obtaining required imaging for the left side, a notable separation between the pectoralis major and minor was seen. this separation was imaged using several orientations and determined not to be an artificial remnant from a previous surgery. the thoracoacromial artery was then identified by general characteristics and confirmed with the application of the color doppler mode. the abnormality, which was identified as a separate and distinct entity, was then captured and stored digitally. this anomalous structure was identified as a possible neuroma of the pectoral nerve (figure 1). the irregular finding was reviewed and discussed with the surgeon before incision. the surgeon planned to visualize the region following dissection and creation of the implant pocket. figure 1. ultrasound image of the pectoral neuroma (shown by arrow). during the dissection of the left pectoral intramuscular space between the pectoralis major and minor for implant pocket creation, the surgeon obtained direct exposure and visualized the suspected neuroma (figure 2). the tissue anomaly was then carefully dissected to reveal a portion of the lateral and most of the medial pectoral nerve. the nerves were carefully stripped of tissue irregularities by the surgeon under direct visualization. the specimen was placed on a card and photographed along with the scar excision from previous left and right infra-mammary incisions, as was typical for this surgeon’s technical protocol anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 5 2018 page 24 (figure 3). the diagnosis was then confirmed to be neuroma by gross examination by the surgeon. during the case the patient received dexamethasone 10 mg in the block solutions and ketorolac 30 mg iv. following an uneventful surgical completion of bilateral breast reconstruction and placement of bilateral breast implants, the patient emerged from general anesthesia and was brought to the recovery room where she stated that the chronic pain in her left upper chest wall region had significantly subsided. discussion this was, to our knowledge, the first reported preprocedural scan diagnosis of a pectoral neuroma by ultrasound that resulted in an alteration of the surgical plan and subsequent outcome. it is plausible that the surgical resection of the neuroma is responsible for the dramatic reduction in chronic pain, however there may factors that have influenced this outcome. it is possible, however, that the significant improvement in pain from this chronic irritation can be explained outside the reduction of the neuroma from the medial and lateral pectoral complex. the surgery itself could have disrupted a potential contracture caused by several surgical traumas and alterations in the subpectoral architecture. alterations in the posterior breast capsule may also have played a role in pain reduction. the regional blockade itself was expected to play a role in postoperative as well as intraoperative pain control, contributing to the relief reported by the patient. the muscle spasm relief described with the intrapec injection, and the iv ketorolac, as part of the multimodal treatment plan, could also have contributed to pain reduction. although not noted during the injection, the local anesthetic could have contacted the medial and lateral pectoral nerves, also blocking pain from those nerves themselves, although the washing out of the pocket before implant placement would likely have reduced the clinical effect and certainly the duration of pain relief. conclusion ultrasound is a reliable, cost-effective, and safe imaging modality, embraced by many clinical professionals who aim to reduce pain. its relevance to this case is unparalleled in utility as it provided the guidance required to safely place regional blockade and incidentally located a potential source of chronic pain. the painful neuroma located by this ultrasound scan, performed for an unrelated purpose, suggested that special attention be paid by the surgeon during the surgical course. in this case the abnormality identified by preprocedural ultrasound provided valuable insight to the cause of pain and was subsequently removed. this provided the patient with significant postoperative relief of a chronic pain condition. figure 2. intraoperative location and confirmation of ultrasound findings of pectoral nerve neuroma. the 2 muscles visible are the dark maroon-colored pectoralis major at the top left portion of the image and the pectoralis minor at the image’s center. note the circled region of tissue representing the large neuroma. figure 3. photo of excised neuroma. the 2 large strings of tissue are from the scar revision caused by previous surgeries. the debulked neuroma tissue appears on the lower right of the card. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 5 2018 page 25 references 1. american society of plastic surgeons website. http://www.plasticsurgery.org. accessed march 26,2018. 2. ivica d, hesham m, felder j, fantus s. nerve injuries in aesthetic breast surgery: systematic review and treatment options. aesthet surg j. 2014;34(6):841–856. doi: 10.1177/1090820x14536726. 3. brummett c. chronic pain following breast surgery. tech reg anesth pain manage. 2011;15(3):124-132. https://doi. org/10.1053/j.trap.2011.07.001 4. jones s, bygrave cj, betts rp, smith tw. morton’s neuroma: a sonographic-surgical evaluation. foot. 1999;9(4):189-192. https://doi.org/10.1054/foot.1999.0562 5. ernberg la, adler rs, lane j. ultrasound in the detection and treatment of a painful stump neuroma. skeletal radiol. 2003;32(5):306-309. https://doi.org/10.1007/s00256-002-0606-9 6. chen pj, liang hw, chang kv, wang tg. ultrasound-guided injection of steroid in multiple postamputation neuromas. j clin ultrasound. 2013;41(2):122-124. https://doi.org/10.1002/jcu.21885 7. torres-claramunt r, ginés a, pidemunt g, puig l, de zabala s. mri and ultrasonography in morton’s neuroma: diagnostic accuracy and correlation. indian j orthop. 2012;46(3):321-325. https://doi.org/10.4103/0019-5413.96390 8. currier a, khayata i. ultrasound as a modality for detection and treatment of an ilioinguinal neuroma. anesthesiology and perioperative medicine publications. university of massachusetts medical school. https://escholarship.umassmed. edu/anesthesiology_pubs/113?utm_source=escholarship.umassmed.edu%2fanesthesiology_pubs%2f113&utm_ medium=pdf&utm_campaign=pdfcoverpages. published march 24, 2012. accessed september 21, 2018. 9. somashekar dk, di pietro ma, joseph jr, yang lj, parmar ha. utility of ultrasound in noninvasive preoperative workup of neonatal brachial plexus palsy. pediatr radiol. 2016;46(5):695-703. https://doi.org/10.1007/s00247-015-3524-4 10. kline j. ultrasound guided intrapec injection: a novel solution for surgical field improvement during electrocautery, implantation, and postoperative pain and muscle spasm reduction for breast surgery. anesthesia ejournal. 2018 july;6. https:// anesthesiaejournal.com/index.php/aej/article/view/87. volume 8no. 6 2020 educated hand publishing llc “the science behind the art” volume 8 no. 6 2020 anesthesia ejournal online issn 2333-2611 page 16 perioperative management considerations for patients on methadone and buprenorphine emily coleman, rn, ccrn, srna affiliation: texas christian university school of nurse anesthesia funding/conflict of interest disclosure: none keywords: methadone; buprenorphine; mu opioid receptor; multimodal analgesia; medication-assistant treatments; anesthesia management abstract a 52-year-old female with a history of chronic pain and methadone therapy was scheduled for spinal cord stimulator removal. patients with chronic pain or opioid use disorders (oud) are often managed with prescriptions or medication-assisted treatments (mat) involving methadone and buprenorphine. existing case studies, expert opinions, and clinical practice advisories recommend continuation of methadone and buprenorphine perioperatively to avoid regimen disruptions and drug level fluctuations. most recommendations are also in agreement for providers to implement multimodal analgesia and incorporate regional/neuraxial anesthesia when appropriate. abrupt discontinuation of methadone can result in opioid withdrawal or place the patient at risk for relapse. buprenorphine is a partial μor agonist with high receptor binding affinity and slow dissociation properties. perioperative buprenorphine management varies widely, but many guidelines and protocols recommend continuing buprenorphine preoperatively. introduction one hundred million people in the united states live with chronic pain and around two million people suffer from substance abuse disorder related to opioids and heroin.1-3 deaths due to drug overdose have increased four-fold between 1999 and 2017.4 many patients undergoing surgery and anesthesia have chronic pain or oud, requiring providers to understand and address the complexity of medications such as methadone and buprenorphine. lack of awareness and ineffective pain management for these patients can result in higher opioid use from inadequate pain control, exacerbation of withdrawal or relapse, and increased risk of cardiac, respiratory, and neurological depression.1-9 aej educated hand publishing llc “the science behind the art” volume 8 no. 6 2020 anesthesia ejournal online issn 2333-2611 page 17 case summary a 52-year-old, 146 kg, 167 cm, female presented for spinal cord stimulator removal. the patient’s past medical history included asthma, mitral valve prolapse without any current issues or symptoms, arthritis, obesity with a body mass index (bmi) of 52, depression, anxiety, and chronic pain. the patient’s past surgical history included stomach surgery, gallbladder surgery, abdominal hysterectomy, tubal ligation, right knee surgery, nerve anastomosis of left arm, and spinal cord stimulator placement. in 2010 the patient was shot multiple times in the left arm and right knee, which led to chronic pain and placement of spinal cord stimulator for pain management in 2014. the patient denied any previous complications with anesthesia. an anesthetic record from 2017 had noted the patient to be a difficult airway. intubation was obtained after three attempts, with successful placement of endotracheal tube facilitated by utilization of glidescope video laryngoscopy, cricoid pressure, and eschmann tracheal tube introducer. her outpatient medication list included albuterol, alprazolam, gabapentin, methadone, venlafaxine, cyclobenzaprine, and topiramate. allergies to erythromycin and penicillin, which both cause respiratory distress for the patient, were reviewed and confirmed. laboratory results from pre-surgery testing were unremarkable. pre-anesthetic evaluation was performed, and the patient reported to have discontinued methadone intake about 6 months ago. the patient was classified as physical status iii. upon arrival to the operating room, the patient maintained supine position on stretcher. physiologic monitors were applied, including pulse oximeter, noninvasive blood pressure (bp) cuff, electrocardiogram (ecg) monitoring, and capnography. pre-induction vital signs were heart rate (hr) 76 beats per minute, bp 165/71 mm hg, oxygen saturation (spo2)100%, respiratory rate of 13, and temperature of 36.2°c. the patient was preoxygenated via face mask with 100% fio2 at 15 l/min. induction was initiated once patient’s end-tidal oxygen concentration levels were above 85%. general anesthesia was induced intravenously with fentanyl 100 mcg, lidocaine 50 mg, propofol 200 mg, rocuronium 50 mg, and ketamine 30 mg. due to a previous anesthesia record from 2017 indicating difficult airway, glidescope video laryngoscopy was utilized, grade i view of vocal cords was obtained, and the airway was secured with a 7.0 mm endotracheal tube. placement confirmation was verified through bilateral breath sounds, positive end tidal carbon dioxide capnography waveform, and symmetrical chest wall movement. sevoflurane 0.6-2.1% was used as anesthetic maintenance agent with oxygen at 1 l/min and air at 1 l/min. initial vital signs post-intubation was hr of 106 beats per min, bp of 162/134, spo2 of 100%. patient was then placed in prone position on a wilson frame for surgery. local anesthesia infiltration was performed by surgical team with wound closure. patient was repositioned to supine position on the stretcher. intravenous medications including ketamine 20 mg, ondansetron 4 mg, methocarbamol 1 g, neostigmine 3 mg, and glycopyrrolate 0.4 mg were administered during emergence of anesthesia. train-of-four monitor revealed 4/4 twitches with sustained tetany for 5 seconds. spontaneous respirations and adequate tidal volumes were maintained. after oropharyngeal suctioning and extubation criteria were met, the endotracheal tube was removed. oxygen at 4 l/min via facemask was applied as patient was transported to post-anesthesia care unit (pacu). post-procedure vital signs were hr 75 beats per minute, bp 140/70 mm hg, spo2 100%, respiratory rate of 16, and temperature of 36.1°c. no anesthesia or surgical complications were noted. patient was discharged from pacu within the same day. discussion the opioid abuse pandemic and increasing numbers of patients with chronic pain presents a multitude of challenges perioperatively and little has been studied to provide high quality evidence as guidance to optimal pain management.1-6 patients with chronic pain or oud are vulnerable and at risk for ineffective pain management, marginalization, opioid withdrawal, and relapse. existing mat for chronic pain or oud involves opioid agonists such as methadone, partial agonists such as buprenorphine, or antagonists such as naloxone. methadone, buprenorphine, and naloxone will complicate the patient’s care perioperatively, due to their pharmacological profile and interpatient variabilities.1-10 figure 1. effect of oud medications on opioid receptors15 pharmacology of methadone  methadone, a synthetic opioid, is a racemic mixture of the r-methadone and s-methadone enantiomer. r-methadone enantiomer is a full μor agonist, while the s-methadone enantiomer is an n-methyl-d-aspartate (nmda) antagonist and prevents serotonin and norepinephrine reuptake.1,2,4-7 recent studies suggest that methadone has a higher potency than previously reported, with a median conversion ratio of methadone to morphine of about 7.75 to 1.7 administration of methadone orally reaches peak plasma drug concentration between two to three hours, with an average half-life of 23 hours.6 the biphasic pattern of elimination observed in methadone is the reason for its effectiveness in mat for chronic pain or oud. the alpha-elimination phase of methadone correlates with its duration of analgesia, which is between 6 to 12 hours. the beta-elimination phase lasts between 30 to 60 hours with sub-analgesic effects, which is sufficient in preventing withdrawal symptoms.7 pain management providers often prescribe methadone to be taken three to four times daily in correspondence to its analgesic and elimination properties.4-8 methadone is commonly prescribed for patients that abuse heroin due to its μor affinity and prolonged half-life. therefore, chronic methadone can attenuate the euphoric effects from heroin to decrease dependence and abuse. methadone has also been utilized in acute pain management in anticipation of significant postoperative pain.4,6 perioperative management of patients on methadone the pharmacological profile of methadone including its potent analgesic effects and extensive half-life are important factors to consider perioperatively.1,2,4-7 life threatening complications such as accumulated toxicity, opioid withdrawal, and overdose can occur in terms of methadone abuse or inadequate management.7 current literature reports a single 40 mg dose of oral methadone could result in death, especially in opioid naïve patients. therefore, providers will also need to be aware of an increased risk of cardiac, respiratory, and neurological depression in patients that are receiving opioids.1 it is imperative to perform a thorough preoperative assessment to gather information on the patient’s history of methadone therapy. details of methadone dosing, level of compliance, and patient’s previous experiences with anesthesia are all necessary information to form an anesthetic plan.1,2,4-7 patients that are diverting their methadone or ingesting other illicit drugs may require further testing such as urine drug screen, electrocardiogram, and liver and renal function tests.5,7 current recommendations advise patients on methadone to adhere to their regimen and continue their normal dose on the day of their surgical procedure.1,2,4-7 patient compliance prevents drug level fluctuations and possible withdrawals.5,7 prescribed daily dose of methadone is inadequate in managing acute pain, therefore providers should consider multimodal pain management strategies.1,2,4-7 opioid-free anesthesia is preferred especially in patients with a history of opioid addiction.1 consider incorporating agents such as volatile anesthetics, ketamine, benzodiazepines, acetaminophen, non-steroidal anti-inflammatory drugs (nsaids), gabapentinoids, alpha-2 adrenergic receptor agonists, local anesthetics, and regional/neuraxial anesthesia.1,2,6,7 there is a lack of research and data on the preferred opioid of choice in treating patients with chronic pain or oud. the goals of administering subanesthetic doses of ketamine, wound infiltration with local anesthesia, and other nonopioid interventions are to decrease opioid requirements while improving pain scores.11 postoperatively, patient’s maintenance methadone dose should be continued as soon as possible.1,2,4-7 if opioids are required for breakthrough pain, some articles recommend short-acting opioids.1,2 studies have reported opioid-dependent patients require four times more narcotics than opioid naïve patients.11 in anticipation of moderate to severe pain postoperatively, patient controlled analgesia (pca) may be appropriate.1,6 lastly, it is important to note that partial opioid agonists such as buprenorphine and butorphanol will precipitate withdrawal symptoms and should be avoided.2 the patient presented in the case study had a history of methadone consumption due to chronic pain that resulted from gunshot inflicted tissue and nerve damage on her left arm. although the patient reported discontinuing methadone therapy, multimodal analgesia and administration of short-acting opioids were still implemented. local anesthesia was also applied by the surgical team intraoperatively. the patient had minimal to no pain in pacu and was discharged within the same day.  pharmacology of buprenorphine  buprenorphine is another common medication approved by the u.s. food and drug administration (fda) for chronic pain or oud. buprenorphine has unique pharmacological features as a partial agonist at the μor and an antagonist of the kappa opioid receptors.3-6 as a partial agonist, buprenorphine has a ceiling effect that minimizes additional opioid effects despite repeated or increased dosing.2-4,8-10 due to the ceiling effect, buprenorphine causes less respiratory depression and has a lower abuse potential compared to methadone.2-4,6-9 despite being a partial agonist, buprenorphine has a high affinity for the μor, therefore it will compete with and displace other full opioid agonists.2,3,8-10 buprenorphine is an effective treatment for oud as it relieves withdrawal symptoms through its partial opioid agonist effects if the μor were not occupied. if buprenorphine is administered or ingested during an euphoric state under the influence of full agonists such as heroin or other opioids, buprenorphine will displace the full agonist and trigger precipitated withdrawal due to a decrease in agonist effect.2,8,9 buprenorphine is available through various routes including sublingual, buccal, transdermal, and injectable formulations.2,4,9 buprenorphine can be administered alone or in combination with an opioid antagonist such as naloxone. the combination of buprenorphine and naloxone decreases the abuse potential due to their bioavailability when administered sublingually compared to parentally. sublingually, buprenorphine has a high bioavailability as it avoids first pass metabolism while naloxone is poorly absorbed. if the combination of the two drugs are injected parenterally, both agents are highly bioavailable which allows naloxone to become active and counteract the euphoric effects.2-4,6,8,9 buprenorphine and mu opioid receptor affinities  buprenorphine has features such as high μor affinity, slow dissociation from the receptor, and prolonged duration with a half-life of 25-60 hours.2,4,10 the majority of opioid analgesic and anesthetic agents bind to the μor, which causes supraspinal analgesia. additionally, μor agonists are responsible for euphoric effects, sedation, respiratory depression, decreased intestinal motility, and physical dependence.12 receptor binding affinity is measured by the equilibrium dissociation constant (ki).10,12,13 opioids with low ki values have stronger binding affinity at the μor. the ki value of buprenorphine is 0.216 nm, exceeded only by sufentanil with a ki value of 0.138 nm (table).10,12,13 a case series recommended utilization of opioids such as hydromorphone or sufentanil with ki values closer to buprenorphine to achieve better analgesia.10 educated hand publishing llc “the science behind the art” volume 8 no. 6 2020 anesthesia ejournal online issn 2333-2611 page 18 figure 2. summary of opioid receptor signaling14 educated hand publishing llc “the science behind the art” volume 8 no. 6 2020 anesthesia ejournal online issn 2333-2611 page 19 table. mu opioid receptor affinity measured by the equilibrium dissociation constant (ki)12-13 drug ki (nm) hydrocodone 41.58 oxycodone 25.87 alfentanil 7.391 methadone 3.378 nalbuphine 2.118 morphine 1.168 fentanyl 1.346 butorphanol 0.7622 oxymorphone 0.4055 hydromorphone 0.3654 buprenorphine 0.2157 sufentanil 0.1380 perioperative management of patients on buprenorphine as a partial agonist with strong μor affinity, buprenorphine attenuates the effect of other μor agonists. the ceiling effect of buprenorphine decreases risks of respiratory depression and overdose but presents a challenge in surgical analgesia.9 therefore, patients taking buprenorphine are at high risk for ineffective pain management leading to severe postoperative pain.2,9 inadequate pain relief may cause longer postoperative recovery times, increased anxiety levels, and provoke drug-seeking behaviors.9 there is a lack of high-quality research and evidence regarding perioperative management of patients on buprenorphine. most guidelines and protocols are derived from expert opinion, case studies, and clinical practice advisories.3,4,11 preoperatively, current literature suggest anesthesia providers to perform comprehensive assessments to obtain patients’ history of buprenorphine therapy and other pertinent information. it is important to review patient’s compliance level with prescriptions, pain management history, and previous experiences with anesthesia.2,5,11 diagnostic testing and toxicology screening should also be considered for objective information.2,3,10 there are conflicting views and concepts regarding preoperative continuation of buprenorphine.2-4,11 some reports recommend discontinuing buprenorphine two to five days prior to surgery to ensure μor availability.2 other sources noted there is a lack of evidence that discontinuing buprenorphine would prevent relapse episodes.3 furthermore, patients that discontinued buprenorphine were found to have a significant increase in opioid requirements postoperatively.4 continuing buprenorphine preoperatively is advocated in some literature to maintain stable serum drug levels and to avoid exacerbations of withdrawal or relapse.2-4,11 optimal perioperative pain management should incorporate non-opioid analgesia as a priority.2-4,9,11 providers could include ketamine, acetaminophen, nsaids, gabapentinoids, and alpha-2 adrenergic receptor agonists.3 local anesthesia infiltration and regional/neuraxial anesthesia should be utilized where possible.2-4,9-11 initiating full μor agonists may be appropriate when inadequate analgesia persists with multimodal management.2-4,11 clinicians need to be aware that successful pain management with patients on buprenorphine often requires increased doses of opioids.2-4,9-11 due to the high μor receptor binding affinity of buprenorphine, other potent full agonists with high ki values may be required to overcome the receptor.10 hydromorphone and sufentanil are examples of μor agonists with ki values similar to buprenorphine.3,10,11 summary while methadone and buprenorphine are the leading medications for treating chronic pain and oud, optimal perioperative management of these medications have not been well established. due to the unique pharmacological profiles of methadone and buprenorphine, it is imperative to perform thorough preoperative evaluations to assess for patient compliance to their prescribed medications, and to discuss concerns of diversion, or possible withdrawal and relapses perioperatively. current guidelines and protocols recommend patients to continue their medication regimen unless instructed differently by their prescribing provider.1-11 optimal perioperative management of patients on methadone may include short-acting opioid agonists, multimodal analgesia, regional/neuraxial anesthesia, and other non-opioid interventions.1,2,4-7 optimal perioperative management of patients on buprenorphine may include multimodal analgesia, regional/ neuraxial anesthesia, and opioid agonists with similar μor binding affinity to buprenorphine.2-4,9-11 references 1. cornett em, kline rj, robichaux sl, et al. comprehensive perioperative management considerations in patients taking methadone. curr pain headache rep. 2019;23(7):49. doi:10.1007/s11916-019-0783-z. 2. ward en, quaye an, wilens te. opioid use disorders: perioperative management of a special population. anesth analg. 2018;127(2):539–547. doi:10.1213/ane.0000000000003477 3. goel a, azargive s, weissman js, et al. perioperative pain and addiction interdisciplinary network (pain) clinical practice advisory for perioperative management of buprenorphine: results of a modified delphi process. br j anaesth. 2019;123(2):e333-e342. doi:10.1016/j.bja.2019.03.044. 4. scholzen e, zeng am, schroeder km. perioperative management and analgesia for patients taking buprenorphine and other forms of medication-assisted treatment for substance abuse disorders. adv anesth. 2019;37:65-86. doi:10.1016/j.aan.2019.08.002. 5. mitra s, sinatra rs. perioperative management of acute pain in the opioid-dependent patient. anesthesiology. 2004;101(1):212227. 6. vadivelu n, mitra s, kaye ad, urman rd. perioperative analgesia and challenges in the drug-addicted and drug-dependent patient. best pract res clin anaesthesiol. 2014;28(1):91-101. doi:10.1016/j.bpa.2014.02.003. 7. peng pwh, tumber ps, gourlay d. review article: perioperative pain management of patients on methadone therapy. can j anaesth. 2005;52(5):513-523. 8. whelan pj, remski k. buprenorphine vs methadone treatment: a review of evidence in both developed and developing worlds. j neurosci rural pract. 2012;3(1):45–50. doi:10.4103/0976-3147.91934 9. roberts dm, meyer-witting m. high-dose buprenorphine: perioperative precautions and management strategies. anaesth intens care. 2005;33(1):17-25. 10. leighton bl, crock lw. case series of successful postoperative pain management in buprenorphine maintenance therapy patients. anesth analg. 2017;125(5):1779–1783. doi:10.1213/ane.0000000000002498 11. coluzzi f, bifulco f, cuomo a, et al. the challenge of perioperative pain management in opioid-tolerant patients. ther clin risk manag. 2017;13:1163–1173. published 2017 sep 5. doi:10.2147/tcrm.s141332 12. volpe da, mcmahon tobin ga, mellon rd, et al. uniform assessment and ranking of opioid μ receptor binding constants for selected opioid drugs. regul toxicol pharmacol. 2011;59(3):385-390. doi:10.1016/j.yrtph.2010.12.007. 13. ellis cr, kruhlak nl, kim mt, hawkins eg, stavitskaya l. predicting opioid receptor binding affinity of pharmacologically unclassified designer substances using molecular docking. plos one. 2018;13(5):e0197734. doi:10.1371/journal.pone.0197734. 14. al-hasani r, bruchas mr. molecular mechanisms of opioid receptor-dependent signaling and behavior. anesthesiology. 2011;115(6):1363-1381. doi:10.1097/aln.0b013e318238bba6. 15. medication-assisted treatment improves outcomes for patients with opioid use disorder. the pew charitable trusts. https://www. pewtrusts.org/en/research-and-analysis/fact-sheets/2016/11/medication-assisted-treatment-improves-outcomes-for-patientswith-opioid-use-disorder. published november 26, 2016. accessed march 26, 2020. about the author: emily coleman is completing the final year of obtaining a doctor of nursing practice at texas christian university. coleman graduated from the university of texas at austin with a bachelor of science in nursing. coleman was one of twelve accepted into the undergraduate nursing honors program and completed a secondary analysis as her honor’s thesis. before beginning her doctoral education, coleman was a medical intensive care nurse at ut southwestern. her background in pulmonary and critical care medicine involved caring for patients with pulmonary hypertension, sepsis, renal failure, respiratory failure, and more. her current professional interests include pharmacology, regional anesthesia, obstetric anesthesia, and pain management. educated hand publishing llc “the science behind the art” volume 8 no. 6 2020 anesthesia ejournal online issn 2333-2611 page 20 https://www.pewtrusts.org/en/research-and-analysis/fact-sheets/2016/11/medication-assisted-treatment-improves-outcomes-for-patients-with-opioid-use-disorder. https://www.pewtrusts.org/en/research-and-analysis/fact-sheets/2016/11/medication-assisted-treatment-improves-outcomes-for-patients-with-opioid-use-disorder. https://www.pewtrusts.org/en/research-and-analysis/fact-sheets/2016/11/medication-assisted-treatment-improves-outcomes-for-patients-with-opioid-use-disorder. anesthesia ejournal volume 3 issue 2 2015 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 medication errors are an important public health problem with high human and financial costs. medication errors in anesthesia can result in patient morbidity or mortality and should be preventable. evidence in the literature supports increasing computer access to reduce the number of medication errors. the purpose of this study was to determine if medication errors could be reduced in one university hospital through a clinical intervention of increasing computer access in the post-anesthesia care unit. a quantitative retrospective chart review was conducted. a statistical test of two independent proportions was used to examine the occurrence of schedule ii (fentanyl) and iv (midazolam) controlled substance documentation errors before and after increasing computer access in the post-anesthesia care unit. access to computers appeared to be associated with a reduction of medication errors from 2.3% to 1.5%. the compliance rate increased from 97.6% to 98.5%. the reduction in the error percentage was significant (z = 2.045, p = 0.04). our findings provide objective evidence for the support of continuous process improvement to reduce medication errors in anesthesia. keywords: medication errors; patient safety; anesthesia documentation; medication documentation; electronic anesthesia record abstract reducing intravenous narcotic documentation errors on the electronic anesthesia record: a quality improvement project john m. borza dnp, mba, crna judith a. kaufmann dr.ph, fnp-bc thomas w. cline ph.d., mba affiliation: university of pittsburgh medical center, pittsburgh, pa, usa. dr borza is clinical director nurse anesthesia. email: borzajm@upmc.edu funding/conflict of interest disclosure: none, irb -university of pittsburgh, quality improvement review committee, qi review number 0001579 introduction medication errors are important public health problems with high human and financial costs. medication errors can result in patient morbidity or mortality and should be preventable. a medication error is defined as a failure in the treatment process that leads to, or has the potential, to lead to harm to the patient.1 yet the literature indicates that medication errors exist and must be addressed.2 in anesthesia, medication errors are particularly problematic and are one of the most prevalent contributors to iatrogenic harm.3 the institute of medicine (iom) report to err is human identified patient safety as a significant problem and suggested that efforts to improve patient safety must focus on systems rather than providers.5,6 medication errors are an appropriate area on which to focus efforts for improving patient safety.6 a substantial need exists for evaluation of interventions to reduce errors. background and significance medication errors in the practice of anesthesia have long afflicted the specialty.7 the first documented medication error related to the administration of anesthesia was in 1848. a 15-year-old girl, hannah greener of the united kingdom, died after receiving a chloroform anesthetic for a minor procedure.8 from the time of that earliest report, medication errors during the administration of anesthesia have persisted. cooper and nossaman7 observed that even though it is common knowledge that medication errors occur in anesthesia, there are few published studies on medication errors. cooper and nossaman’s7 systematic review contained only 14 articles, 3 of which were symposium reviews on medication errors. only 5 articles using surveys specifically addressed medication errors during the administration of anesthesia. despite the reports on medication errors and adverse events, few of the studies within the systematic review specifically addressed the rate of medication errors in anesthesia practice until 2001. bowdle9 reviewed nearly 6000 closed or settled anesthesia malpractice claims and found 205 medication errors. medication errors resulted in 24% mortality and 34% morbidity with an estimated annual cost of $2.8 million for a 700-bed hospital. in 2011, hanna and levine3 reported that 1 error occurs for every 133 anesthetics. flynn et al10 reported that there are 300 near misses for every error reported. the national cost of all hospital medication errors is estimated to exceed $3.5 billion dollars annually,11 and up to 7000 patients die each year as a result of medication errors.3 on the basis of earlier reports on anesthesia errors, the robert wood johnson foundation reinforced the conclusion that a key to reducing patient risk is to shift the focus from individuals, who will always make some errors, to systems, which can be redesigned to help prevent errors.7 the iom report (2006), the joint commission (2008), and the anesthesia patient safety foundation (2010) recommended changes in work processes to reduce medication errors.7 medication documentation errors occur despite knowledgeable and competent anesthesia providers. the problem of medication administration in anesthesia is of particular concern because of the potent agents administered. for the present study, a baseline evaluation of medication errors was undertaken. in an analysis of 2 months of electronic anesthesia records compared with pharmacy controlled substance sheets of schedule ii (fentanyl) and iv (midazolam) medications at a university medical center, 63 intravenous narcotic medication errors were identified among 2495 anesthetic cases. three types of medication documentation errors were identified. the least common medication documentation error, with an error rate of 7.6 per 1000, was that the anesthesia provider did not sign the pharmacy controlled substance sheet. the second most common error, with an error rate of 6.4 per 1000, was that the anesthesia provider miscounted on the pharmacy narcotic sheet, but the correct medication dosage was administered to the patient. in most cases found in the data, with an error rate of 15.3 per 1000, the patient was administered the medication, but the medication was not recorded on the electronic anesthesia record. there was no reported harm to patients, but medication errors place the patient at risk. intravenous narcotic medication documentation errors on the electronic anesthesia record may result in patient morbidity or mortality. inaccurate or incomplete documentation can lead to over-medication or under-medication, resulting in potential harm. cause analysis revealed several factors that contributed to the documentation errors. these factors encompassed technology, policies and regulations, system processes, and accountability. there was a lack of computer access in patient care areas, a lack of real-time decision support, a lack of anesthesia providers who adhered to documentation policy, an inefficient electronic record conversion process that did not include all patient care areas, a lack of a clear documentation process that included a process to detect documentation errors, and a lack of counseling after identification of a documentation error. purpose of study based on the above baseline evaluation of anesthesia-related medication errors, the primary aim of this quality improvement project was to achieve 100% accuracy in documenting intravenous schedule ii and iv controlled substances on the electronic anesthesia record within the facility. this quality improvement project will enable the university medical center to meet us drug enforcement agency requirements and comply with university medical center policies. review of the literature in preparation for the planning of this research translation study, a comprehensive evaluation of the literature for medication errors, medication reconciliation, and quality improvement design was performed. no inclusion or exclusion criteria were utilized because of the limited number of articles published on medication errors in anesthesia. databases utilized for the search were pubmed and cinahl. search terms entered into pubmed were (“medication reconciliation methods” and “anesthesia”), causes of reconciliation errors, anesthesia and safety and decrease morbidity, medication reconciliation, pdsa, and documentation errors on the anesthesia record. the search term entered into cinahl was “develop a medication reconciliation process.” the search strategy identified 806 citations. after title and abstract review, 13 articles were considered relevant. by hand searching the reference lists of relevant articles and by use of the google search engine, 14 additional articles were found to be relevant. a total of 27 articles were pertinent to the study (figure 1). figure 1. results of the literature search: evidence base for the intervention. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 the level and the quality of the accepted articles were judged by using the johns hopkins evidence level and quality rating scale.12 rating scales present a structured way to differentiate evidence of varying strengths and quality. strong evidence of high quality more likely represents best practice than evidence of lower strength and less quality. level i of the 5 levels used in the rating schemes indicates evidence obtained from an experimental study, randomized controlled trial (rct), or systematic review of rcts, with or without meta-analysis. level ii indicates evidence obtained from a quasi-experimental study or systematic review of a combination of rcts and quasi-experimental studies, or quasi-experimental studies only, with or without meta-analysis. level iii indicates evidence from a quantitative nonexperimental study; systematic review of a combination of rcts, quasiexperimental, and nonexperimental studies, or nonexperimental studies only with or without meta-analysis; or qualitative study or systematic review of qualitative studies, with or without a meta-synthesis. level iv indicates expert opinion of respected authorities and/or nationally recognized expert committees or consensus panels based on scientific evidence. level v, being the lowest level, indicates experiential and nonresearch evidence. quality is based on a scale from a to c with a being the highest and c being the lowest. evidence with a quality rating of a is consistent; has generalizable results, a sufficient sample size for the study design, and adequate control; has definitive conclusions; and has consistent recommendations based on comprehensive literature review that includes thorough reference to scientific evidence. evidence with a quality rating of b has reasonably consistent results, a sufficient sample size for study design, some control, fairly definitive conclusions, and reasonably consistent recommendations based on fairly comprehensive literature review that includes some reference to scientific evidence. evidence with a quality rating of c has inconsistent results, insufficient sample size for the study design, and a lack of conclusions.12 of the relevant articles identified, 1 ranked at level i, 2 at level ii, 9 at level iii, 11 at level iv, and 4 at level v. all varied from a to c in quality (figure 2). figure 2. johns hopkins evidence level and quality rating scale. the consistent findings from these articles, guidelines, and best practices suggested that individual and system factors contribute to medication errors. in health care, accountability for medication errors is commonly attributed to the individual, and the “five rights” in medication administration is commonly used as the benchmark for individual performance. the “person” approach seeks to attribute causes to the individual, whereas the “systems” approach attributes that human error is to be expected. it is suggested that when system barriers are not effective, errors will occur.13 information technology is recommended to overcome such system barriers. information technology can improve anesthesia patient safety by minimizing medication errors and adverse events.14 implementing a multimodal system that includes real-time charting was proven to be effective in reducing medication errors in a prospective randomized open label clinical trial.4 it is also recommended that technology be implemented at every anesthesia location.2,7 there were a number of limitations to the review of the literature. these limitations were that the definition of a medication error is debatable,6 the studies performed were at single health care facilities,15 staff were resistant to change,11 errors were reported on a voluntary basis,7 and studies were not blinded.4 theoretical models two theoretical models were used to develop this quality improvement project: the diffusion of innovation theory of rogers16 and the translation framework plan-do-study-act (pdsa) cycle. rogers’ diffusion of innovation was selected because it outlines a process for change, which starts with an initial few and grows until critical mass is achieved. the pdsa cycle is the accepted format used when implanting a new process improvement in the work setting. the diffusion of innovation theory is often regarded as a valuable change model for guiding technological innovation when the innovation itself is modified and presented in ways that meet across all levels of adopters. it also stresses the importance of communication and peer networking within the adoption process.17 diffusion of innovation refers to the process that occurs as people adopt new ideas. bridging the evidence gap will not be achieved simply by informing clinicians about the evidence.18 rogers outlined this process of change and stressed that, in most cases, an initial few are open to the new idea and adopt its use. as these early innovators “spread the word,” more people become open to the idea and a critical mass is reached. over time, the innovative idea diffuses among the staff until a saturation point is achieved. rogers distinguished 5 categories of adopters of an innovation: innovators, early adopters, early majority, late majority, and laggards. rogers estimated the percentages for each category, which take the shape of a normal bell curve (figure 3). figure 3. diffusion of innovation adopter categories. source: kaminski, 2011.17 anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 the pdsa cycle is used to develop and test rapid change for quality improvement. the main objective in pdsa quality improvement is to assess whether an intervention that changes a process produces an improvement outcome. the pdsa cycle uses the scientific method to answer, “how will we know that a change is an improvement?” the pdsa model advocates the formation of a hypothesis for improvement (plan), a study protocol with collection of data (do), analysis and interpretation of the results (study), and the iteration for what to do next (act) (figure 4). for the present study, the “plan” was to reduce the number of documentation errors of schedule ii and iv controlled narcotic substances on the electronic anesthesia record. the “do” was to increase access to computers in the post-anesthesia area. the “study” was to statistically analyze the results, and the “act” was to determine whether the cycle needed to be performed again with a modified intervention or whether a process change could proceed in practice. figure 4. plan-do-study-act cycle. methods study design the study design was a quantitative retrospective chart review to examine the occurrence of schedule ii and iv controlled substance documentation errors before and after increasing computer access in the post-anesthesia care unit. population and setting the study received institutional review board approval from the university and the university medical center. a retrospective chart review included all surgical patients undergoing anesthesia in the main operating suite from march 3, 2014, to april 2, 2014. charts for patients who had endoscopy procedures, off-site procedures, and procedures such as cardiac catheterizations in the special procedure unit were excluded. sample size estimation for this study we used the alpha significance level of 0.05, and the standard power of 80 percent, as well as a compliance rate of 0.03 for the pre-intervention month and a zero for the postintervention month as one for 100% compliance. a final sample size of 320 was calculated for the pre-intervention month and the same sample size for the post-intervention month. intervention the intervention was designed to increase access to computers in the post-anesthesia care unit at the bedside during the transfer of care process. there were dedicated computers for the anesthesia providers. if a computer was unavailable because another anesthesia provider was using the machine, the post-anesthesia care unit registered nurse provided access to the bedside computer. the anesthesia providers completed documentation and used their computer screen to provide a transfer of care to the post-anesthesia care unit registered nurse. the study was introduced at an operating suite meeting, which included the post-anesthesia care unit staff, anesthesia staff, and the operating suite staff as well as the operating suite leadership. after a slide presentation of the capstone project, a question and answer period was available to address concerns and questions. reliability of documentation and adherence to the intervention protocol was maximized by the support of anesthesia leadership, who observed the compliance of anesthesia providers using the dedicated computers. anesthesia providers who chose not to participate were encouraged to do so, but participation for the purposes of this study period was not mandated. although exact compliance rates were not obtained, a general consensus was that nearly all of the anesthesia providers participated on various shifts. overall, the post-anesthesia care nurses observed a consistent use of the computers. time period the period for the study was from january 2013 through april 2014. during the intervention period, 2 emails were sent to the anesthesia staff to motivate and reinforce engagement. measurements the study compared narcotic medication documentation errors before and after the initiation of increased computer access in the post-anesthesia care unit. data were collected by using a customdesigned microsoft excel (microsoft corp, redmond, wa) spreadsheet (appendix i). demographic variables were collected. the outcome variables were schedule ii and iv controlled substance documentation errors. the data sources were the electronic anesthesia record, the pharmacy narcotic form, and the intraoperative note on the electronic anesthesia record. the data abstractors who reviewed and coded each chart had an important role with respect to data quality.19 two data abstractors were trained to collect the data with one abstractor having no anesthesia background to reduce bias. inter-rater reliability was achieved by using cohen’s kappa. with the range of -1, which demonstrates perfect disagreement, to +1, which demonstrates perfect agreement, the study rated a score of +1 for reviewing 1612 charts.19 data collection all data were collected on paper and computers. all data were de-identified and protected in a locked office and on computers that were password protected. all participants and individuals associated with the quality improvement study adhered to the university medical center’s policies on confidential information, proper handling of protected health information outside of the medical center, and electronic mail and messaging. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 results preand post-intervention compliance rates and medication errors of schedule ii and iv controlled substances were collected from january 2013 to april 2014. a total of 4107 anesthetic cases were included in the study. additional demographic variables collected included assigned study identification number, surgical date, patient fin number, gender, age, american society of anesthesiologists (asa) physical status, types of error, surgical procedure, operating room number, medication variance, anesthesia providers, surgeon, circulating registered nurse, scrub technician, type of narcotic storage, and whether the event was in the am or pm for future studies. medication errors decreased from a combined january-february 2013 error rate of 23.6 per 1000 to an error rate of 14.9 per 1000 in march 2014. the january error rate was 30.0 and the february error rate was 16.7 per 1000, respectively. the compliance rate in march increased to 98.5% from the combined rate of 97.6% for january-february. the january compliance rate was 97.0% and that for february was 98.3%. the error percentage rate decreased in march to 1.48% from 2.36% for january-february combined. the january error percentage rate was 3.0% and that for february was 1.67%. comparing the medication error rate to the national average, real-time bedside computer access reduced the error rate from 3.15 times the national average in january-february combined to 1.98 times the national average for the intervention month (march). the error rate for january represented 3.99 times the national average, whereas that for february was 2.23 times the national average (table 1). table 1. medication error rate march showed a significant reduction in error percentage compared with january 2013 (z= 2.69, p = 0.007). thus, we can conclude that the proportion of errors in march is significantly lower than errors in january, at the 0.01 level of significance. march also showed a reduction in error percentage compared with february; however, the difference in the two proportions was not statistically significant (z = 0.38, p = 0.699). comparing march with january and february combined showed a significant reduction in error percentage (z = 2.04, p = 0.04; table 2).table 2. significance of medication error rates anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 discussion compared with a lack of computer access at the bedside in the post-anesthesia care unit, access to computers appeared to be associated with a reduction of medication errors from 2.3% to 1.5%. the compliance rate increased from 97.6% to 98.5%. it is unknown why january 2013 had an error rate of 3% and february 1.67% with compliance rates of 97% and 98.3%, respectively, while the same documentation process occurred. owing to the disparity in errors between january and february 2013 with no known cause, the 2 months were combined for the purposes of this study, assuming that january could have been a month with less vigilance in documentation than february. although it was shown that the intervention was associated with statistically significant (p=0.04) improvement in the error rate, the results were still below the national average of 0.752 error percentage and 99.2% compliance. the question arises of whether making participation in the study mandatory would have decreased the error rate and increased compliance more to meet or exceed the national averages. our findings were also consistent with a previous study by merry et al,4 which described a reduction in medication errors by using a multimodal approach, whereas the present study implemented a single intervention. merry et al did not identify which intervention had the largest impact. previous studies that addressed medication errors in anesthesia were limited to voluntary surveys. even though our study was voluntary, the medication errors were extracted from the electronic anesthesia record and pharmacy narcotic sheet, which maximized objectivity and the accuracy of the results. limitations the study was implemented at a single university setting. one of the data abstractors was an anesthesia provider who could have been a source of bias. anesthesia leadership designed and conducted the study, which may have been a source of bias. the anesthesia providers may have felt pressured to participate. comparisons of study results with previous studies are limited owing to a lack of a clear definition of medication errors. last, participation in the study was voluntary, which may have influenced the number of medication errors. future research our results suggest a need for improvement in the accuracy of medication recording in anesthesia. our findings provide objective evidence for the support of continuous process improvement. there is a lack of computer access in patient care areas, a lack of real-time decision support, a lack of anesthesia providers who adhere to documentation policy, an inefficient electronic record conversion process that does not include all patient care areas, a lack of a clear documentation process that includes a process to detect documentation errors, and a lack of counseling after identification of a documentation error. use of a multimodal approach in future interventions is warranted. implications errors in medication administration are an ongoing source of concern in anesthesia and in health care in general.4 this study demonstrates that having computer access at the bedside reduces medication errors. no patients sustained increased morbidity or died as the result of medication errors during the time frame. the implications for practice are focused on patients, anesthesia staff, and systems. the first and foremost is improved patient safety and outcomes. reducing medication errors maximizes safe care of the patient. anesthesia providers must be provided with the tools needed to provide safe care and to document in real time. policies and laws are in place to protect the patient and anesthesia staff from making errors. increasing compliance in medication errors will meet university medical center medication policies and the laws of the us drug enforcement agency. conclusion medication errors in the practice of anesthesia have long afflicted the specialty. medication errors may result in patient morbidity or mortality and should be preventable. given the adverse effects of medication errors, there is a substantial need for evaluation of interventions to reduce errors through process improvement. cause analysis revealed a number of factors that contribute to documentation errors. addressing one factor, the lack of computer access in patient care areas, by increasing computer access in the post-anesthesia care units did reduce the number of medication errors. acknowledgements many thanks to the faculty of robert morris university, specifically, judith kaufmann, drph, fnp-bc. their guidance and support throughout this study was instrumental. in addition, thank you to dr. daniel sullivan, dr. mark hudson, dr. jacques chelly, and ms. janet lindner for their mentorship and assistance throughout. also, thank you to the anesthesia leadership and staff at the university of pittsburgh medical center, passavant for their support. and of course, many thanks to my wife, katherine, daughter, melissa, and son, tyler, for their unwavering moral and emotional support of my academic pursuits; without them this journey would not have been possible. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 references 1. aronson jk. medication errors: definitions and classification. br j clin pharmacol. 2009;67(6):599-604. doi:10.1111/j.13652125.2009.03415.x. 2. eichhorn jh. apsf hosts medication safety conference: consensus group defines challenges and opportunities for improved practice. apsf newsletter. 2010;25(1,1-20):1-8. http://www.apsf.org/newsletters/html/2010/spring/01_conference.htm. accessed october 16, 2015. 3. hanna gm, levine wc. medication safety in the perioperative setting. anesthesiol clin. 2011;29(1):135-144. doi:10.1016/j. anclin.2010.11.009. 4. merry af, webster cs, hannam j, et al. multimodal system designed to reduce errors in recording and administration of drugs in anaesthesia: prospective randomised clinical evaluation. bmj. 2011;343:d5543. doi:10.1136/bmj.d5543. 5. kohn lt, corrigan jm, donaldson ms, eds. to err is human: building a safer health system. washington, dc: national academy press; 2000. 6. pronovost p, weast b, schwarz m, et al. medication reconciliation: a practical tool to reduce the risk of medication errors. j crit care. 2003;18(4):201-205. http://dx.doi.org/10.1016/j.jcrc.2003.10.001. 7. cooper l, nossaman b. medication errors in anesthesia: a review. int anesthesiol clin. 2013;51(1):1-12. doi:10.1097/ aia.0b013e31827d6486. 8. knight pr 3rd, bacon dr. an unexplained death: hannah greener and chloroform. anesthesiology. 2002;96(5):1250-1253. http://dx.doi.org/10.1097/00000542-200205000-00030. 9. bowdle ta. drug administration errors from the asa closed claims project. asa newsl. 2003;67(6):11-13. 10. flynn ea, barker kn, pepper ga, bates dw, mikeal rl. comparison of methods for detecting medication errors in 36 hospitals and skilled-nursing facilities. am j health syst pharm. 2002;59(5):436-446. 11. young b. medication reconciliation matters. medsurg nurs. 2008;17(5):332-336. 12. dearholt s, dang d. johns hopkins nursing evidence-based practice: models and guidelines. indianapolis, in: sigma theta tau international; 2012. 13. brady am, malone am, fleming s. a literature review of the individual and systems factors that contribute to medication errors in nursing practice. j nurs manag. 2009;17(6):679-697. doi:10.1111/j.1365-2834.2009.00995.x. 14. bloomfield el, feinglass ng. the anesthesia information management system for electronic documentation: what are we waiting for? j anesth. 2008;22(4):404-411. doi:10.1007/s00540-008-0643-1. 15. vogelsmeier a, pepper ga, oderda l, weir c. medication reconciliation: a qualitative analysis of clinicians’ perceptions. res soc adm pharm. 2012;9(4):419-430. doi:10.1016/j.sapharm.2012.08.002. 16. rogers em. diffusion of innovations. 5th ed. new york: free press; 2003. 17. kaminski j. diffusion of innovation theory. canadian journal of nursing informatics. 2011. http://cjni.net/journal/?p=1444. accessed april 19, 2014. 18. sanson-fisher rw. diffusion of innovation theory for clinical change. med j aust. 2004;180(6). https://www.mja.com.au/ journal/2004/180/6/diffusion-innovation-theory-clinical-change. accessed april 19, 2014. 19. vassar m, holzmann m. the retrospective chart review: important methodological considerations. j educ eval health prof. 2013;10:12. doi:10.3352/jeehp.2013.10.12. anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 http://www.apsf.org/newsletters/html/2010/spring/01_conference.htm anesthesia ejournal www.anesthesiaejournal.com volume 3 issue 2 2015 appendix i: measurement instrument anesthesia ejournal volume 4 issue 1 2016 aej educated hand publishing llc “the science behind the art” anesthesia ejournal online issn 2333-2611 page 34 an anesthesia quality improvement project to improve postoperative pain outcomes after hysterectomy maj jacob l. deeds1,2,3 dnp, crna, anc, usa maj priscilla n. shaw2 dnap, crna, anc, usa ltc aaron r. elliott1 dnp, crna, anc, usa brett t. morgan3 dnp, crna affiliation: 1 william beaumont army medical center, fort bliss, tx 2 united states army graduate program in anesthesia nursing, fort sam houston, tx 3 duke university, durham, nc funding/conflict of interest disclosure: none keywords: preemptive, preventive, gabapentin, intravenous acetaminophen, postoperative pain introduction background each year, over 100 million inpatient and outpatient surgeries occur,1,2 with over 80% of these patients complaining of postoperative pain.3 eighty-six percent of these patients will describe their pain as moderate, severe, or extreme.3 ineffective control of pain after surgery prevents early mobilization, increases side effects related to treatment, lengthens post-anesthesia care unit (pacu) stay, increases hospital admission rates, delays discharge home, and decreases patient satisfaction.4,5 the effect on health care costs is dramatic. hospital stays in the united states cost $1960 per day, on average.6 poor early postoperative pain management not only increases a patient’s length of stay but is reported to be a primary cause of chronic pain,7 now costlier on an annual basis than treatment of cancer, heart disease, or diabetes.8 moreover, opioids, the mainstay of postoperative pain management,9 have demonstrated efficacy but their use potentially contributes to these escalating costs. oderda et al4 demonstrated that 2.7% of patients experience an opioid-related adverse event resulting in significant increases in length of stay (0.53 days) and an additional $840 in hospital costs per event. postoperative pain is nondiscriminatory, affecting patients across the surgical spectrum. however, women who undergo hysterectomies are a uniquely vulnerable population. each year, 500,000 hysterectomies are performed in the united states, making this the second most common major surgery for women.10 minimally invasive techniques, such as vaginal or laparoscopic hysterectomies, have been shown to decrease overall complication rates, the length of hospital stay, and pain, when compared with abdominal hysterectomy.11 nevertheless, high ratings of pain occur even when minimally invasive techniques are used, with patients rating their pain as moderate to severe.12,13 abstract an anesthesia quality improvement initiative implemented an evidence-based, preemptive, preventive multimodal analgesic regimen to improve perioperative pain outcomes for women undergoing hysterectomy. although statistical significance was not achieved, clinically significant decreases in post-anesthesia care unit (pacu) narcotic usage, pain ratings, time in the pacu, and opioid-related side effects were observed. this analgesic regimen was easily implemented, readily modifiable, and suitable for expansion to multiple surgical populations to supplement customary anesthesia perioperative care. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 35 an ideal anesthesia analgesic regimen is safe, inexpensive, rapidly administered, and effective.14 unfortunately, effective analgesic techniques, such as epidurals or spinals, carry intrinsic risks, are time-intensive, require special postoperative monitoring, and do not always appeal to patients.5 the american association of nurse anesthetists (aana) standards for nurse anesthesia practice15 and the american society of anesthesiologists (asa) practice guidelines for acute pain management in the perioperative setting16 recommend utilization of preemptive,15 multimodal15,16 pain management regimens when possible. preemptive analgesia is the administration of an analgesic prior to noxious stimuli with the goal of decreasing acute pain upon insult and decreasing pain-related modulation of the central nervous system, thereby inhibiting postoperative pain.17 multimodal analgesia is the administration of 2 or more different agents that act by different mechanisms to provide better analgesia than single modalities and minimize analgesic-associated side effects.8 this quality improvement project was undertaken to implement an evidencebased, preemptive, multimodal analgesic regimen to improve perioperative pain management outcomes in patients undergoing hysterectomy in a local setting where 5 to 10 hysterectomies are performed monthly. local problem between june 2014 and september 2014, at the author’s local institution, data were prospectively collected on 25 consecutive hysterectomies demonstrating that women undergoing hysterectomies experience moderate to severe postoperative pain. data collected included (1) the amount of analgesics (morphine equivalents) administered in the pacu, (2) pain ratings every 15 minutes (on an 11-point numeric rating scale, a validated pain assessment tool,18 with 1-3 indicating mild pain, 4-6 moderate pain, and 7-10 severe pain), (3) the incidence of opioid-related adverse events, and (4) time spent in the pacu. the median time in the pacu was 72 minutes, determined by pacu admission time until discharge criteria were achieved, and the total median analgesic dose administered in the pacu, in morphine equivalents, was 7.5 mg. opioids administered during the data collection period were exclusively fentanyl, morphine, and hydromorphone. a median pain rating of 5 was reported on admission, 6 after 15 minutes, 5 after 30 minutes, 5.5 after 45 minutes, and 5 after 60 minutes. no preemptive analgesia was observed and 20% of these patients had analgesic regimens that were non-multimodal and consisted entirely of opioids. the incidence of opioid-related adverse events was 20%, with 4 patients complaining of nausea and 1 patient experiencing respiratory depression. intended improvement this quality improvement project aimed to utilize a preemptive, multimodal analgesic regimen for 100% of patients undergoing hysterectomy to decrease postoperative opioid use, opioid-related adverse events, pacu pain scores, and time in the pacu. quality improvement question the primary question addressed was, “in women undergoing hysterectomy, will the addition of an evidence-based preemptive analgesic regimen improve pain control, decrease the requirement for opioid pain medications, decrease opioid-related adverse events, and decrease the time spent by patients in the pacu compared to customary analgesic regimens?” methods ethical issues no protected health information was logged for this project. all data were retrieved from the patient’s electronic medical record on the day after surgery and recorded in an spss (ibm corp) dataset for analysis. the data collected during this quality improvement project did not include information that would allow any person to identify the participants. the spss dataset was saved on a department of defense secure server in a password-protected folder. the project was submitted to the local institutional review board (irb) for a quality improvement study determination and did not satisfy the definition of “research” under us code of federal regulations 32 cfr 219.19 the irb application stated the project was aimed at “improving local systems of care utilizing an accepted multimodal approach to perioperative analgesia in accordance with practice guidelines” (m abel, unpublished memorandum, april 1, 2014). subsequent to local irb determination, the project was also submitted to the duke university irb, which concurred with the local determination. setting the setting was a military treatment facility located in the southwestern united states serving over 100,000 beneficiaries who receive care within the military health system. beneficiaries of this military health system include all age groups and consist primarily of active duty service members and families, national guard/reserve members, and retired service members and families.20 the surgical department comprised 10 operating rooms, encompassing approximately 800 surgeries per month, of which 5 to 10 were hysterectomies performed by the obstetricalgynecological surgical service (e leiter, personal communication, march 20, 2014). the anesthesia staff consisted of 23 certified registered nurse anesthetists (crnas) and 9 physician anesthesiologists. planning the intervention the analgesic regimen instituted consisted of preoperative administration of 600 mg oral gabapentin and 1 g intravenous (iv) acetaminophen. the regimen was derived from the asa practice guidelines for acute pain management in the perioperative setting recommendations,16 the aana standards for nurse anesthesia practice,15 a review of the literature, and anesthesia staff experience with multimodal regimens in other institutions similar to the author’s. there was much discussion on whether to utilize oral versus iv acetaminophen. owing to a lack of evidence comparing the 2 routes, we selected the iv formulation secondary to the varied absorption rates of oral acetaminophen prior to surgery,21 increased peak plasma levels of iv acetaminophen,22 increased cerebral spinal fluid levels of iv acetaminophen,22 and the preference for iv over oral by our anesthesia providers. the sample and inclusion criteria consisted of (1) patients scheduled for hysterectomy (total laparoscopic, laparoscopic assisted, vaginal, or transvaginal), (2) 20-55 years of age, and anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 36 (3) physical status score of i-iii, representing patients without severe systemic disease processes. exclusion criteria consisted of (1) hypersensitivity to gabapentin or acetaminophen, (2) renal insufficiency, or (3) liver disease. no patients were required to be excluded. patients were identified 5 days prior to surgery via the operating room schedule. on the day of surgery, patients followed the normal protocol, arriving at the hospital at least 2 hours in advance of their surgery. upon arrival to the preoperative holding area, approximately 1 hour before the start of surgery, the patient received 600 mg gabapentin with a small sip of water, administered by the preoperative holding area nurse or anesthesia staff. approximately 30 minutes prior to the start of surgery, 1 g iv acetaminophen was administered over 15 minutes. the administration of iv acetaminophen and gabapentin at these times was important, as their respective peak effects coincided with the onset and cessation of the surgery, respectively. any additional analgesics required were determined in the customary way by the assigned anesthesia provider to that surgical case. assessment in the pacu was done in standard pacu fashion (pain assessments, pain interventions, and traditional modified aldrete scoring every 15 minutes) with no additional assessments required by the pacu staff. planning the study of the intervention the project aimed to improve postoperative analgesic outcomes following hysterectomy. analysis of the outcomes consisted of a pre/post design with a period of pre-implementation (customary analgesic regimens) data collection, a period of instruction to applicable staff (surgeons, anesthesia providers, pacu nurses) regarding implementation of the quality improvement project, and a period of post-implementation (preemptive multimodal regimen of iv acetaminophen and gabapentin supplemented by our customary analgesic regimens) data collection. quantitative data collected by the pacu nurses for every hysterectomy patient in the recovery room were used to evaluate the aims. additionally, age, weight, duration of surgery, type of hysterectomy, and the presence of preoperative chronic pain were collected as baseline variables. these items were predetermined by the gynecological and anesthesia staff as possible variables that could affect the outcomes independent of the analgesic regimen. methods of evaluation data evaluating the aims of this project were collected directly from the patient’s chart by the author and input into an spss dataset on the day after surgery. prior to data collection, the author analyzed the patient’s electronic medical record and ensured the designated regimen had been performed in the proposed manner. primary outcomes were reflective of the aims of the project, whereas secondary outcomes provided additional analysis. primary outcomes were (1) pain assessment on admission to the pacu, and at each 15-minute subsequent assessment, using an 11-point verbal rating scale; (2) pacu total opioid use converted to morphine equivalents; (3) time from pacu admission to the time at which criteria were met for discharge; and (4) absence or presence of opioid-related adverse events defined as nausea, vomiting, respiratory depression, dizziness, or sedation. the secondary outcomes were (1) intraoperative opioid use converted to morphine equivalents; (2) time from the end of surgery to removal of the endotracheal tube (extubation); and (3) time to first analgesic administration in the pacu. analysis the aims of this project were to improve analgesic outcomes as evidenced by decreased opioid administration, pain ratings, opioid-related adverse events, and time in the pacu. descriptive statistics were used to summarize the data and comparisons were made between the pre-implementation and postimplementation groups to determine if the aims were achieved. we further compared the groups by using inferential statistics, as determined by the distribution of the data and assumptions of proposed statistical tests. for interval and ratio level data that met assumptions, a two-tailed independent t-test was utilized (time in the pacu). mann-whitney u tests were conducted if assumptions were not met (pacu morphine equivalents, pain ratings). categorical secondary outcomes (absence or presence of opioid-related adverse events) were analyzed by using pearson’s chi-squared test. relationships between variables were further investigated by using a pearson or spearman’s correlation. analysis was executed by using spss statistics version 21 (ibm corp). anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 37 results outcomes there were no significant differences in baseline characteristics between the preand post-implementation groups. each group was similar in age, weight, duration of surgery, preexisting chronic pain, and type of hysterectomy (table 1). compared with patients in the pre-implementation group, patients in the preoperative gabapentin and iv acetaminophen group showed improvements in all primary outcomes and in all but one of the secondary outcomes (table 2). pacu analgesics in morphine equivalents were reduced 33%, and time in the pacu (minutes) was reduced by 13%. in both groups, the opioids utilized were exclusively fentanyl, morphine, and hydromorphone. secondary outcomes showed similar improvements for 2 of the outcome measures, whereas 1 of the outcomes slightly worsened. comparing patients in the pre-implementation group with those in the postimplementation group, intraoperative analgesic administration was reduced in morphine equivalents by 21% and time to first analgesic administration was delayed 5%, whereas the time from the end of surgery to extubation was prolonged by 6.2%. table 1. baseline characteristics of the groupsa pre-qi implementation data (n= 25) post-qi implementation data (n=25) p value age, years (± sd) 39.32 ± 6.16 41.16 ± 7.69 0.36 weight, kg (± sd) 86.08 ± 18.37 79.34 ± 17.61 0.19 duration of surgery, min 103 110 0.15 preexisting chronic pain (yes/no) 1/24 5/20 0.19 type of hysterectomy, trans/tvh/tlh/ lavh (number of each performed) 5/17/1/2 7/15/1/2 0.93 abbreviations: lavh, laparoscopically assisted vaginal hysterectomy; qi, quality improvement; tlh, total laparoscopic hysterectomy; trans, transvaginal hysterectomy; tvh, total vaginal hysterectomy. athe pre-implementation group did not receive preoperative gabapentin and iv acetaminophen. the post-implementation group received 600 mg preoperative gabapentin and 1 g iv acetaminophen. there were no significant differences between the pre-implementation and post-implementation groups. table 2. primary and secondary outcomes before and after implementationa pre-qi implementation data (n=25) post-qi implementation data (n=25) p value percentage change pacu analgesics, morphine equivalents 7.5 5 0.62 33% reduction time in pacu, min (± sd) 75.12 ± 32.81 65.12 ± 22.01 0.21 13% reduction intraoperative analgesics, morphine equivalents 31.67 25 0.14 21% reduction time to extubation, min (± sd), from end of surgery 5.8 ± 3.10 6.16 ± 5.12 0.77 6% increase time to first analgesic in pacu, min (± sd) 19.83 ± 13.16 20.79 ± 13.02 0.83 5% increase abbreviations: pacu, post-anesthesia care unit; qi, quality improvement. apre-implementation group received customary care decided by anesthesia provider. post-implementation group received preoperative gabapentin and iv acetaminophen in addition to typical care as determined by anesthesia provider. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 38 percentage change in pain scores varied from a 5% to 10% reduction at admission, 15, 45, and 60 minutes in the pacu, although there was no difference in pain scores at 30 minutes. the incidence of opioid-related adverse events was reduced by 80% (table 3). table 3. comparison of pain ratings before and after implementationa numeric rating scale pre-qi implementation data (n=25) post-qi implementation data (n=25) p value percentage change admission 5 4 0.94 10% reduction 15 minutes 6 5 0.88 10% reduction 30 minutes 5 5 0.68 0% reduction 45 minutes 5.5 5 0.36 5% reduction 60 minutes 5 4.5 0.44 5% reduction opioid-related adverse events, no. of episodes nausea (4) respiratory depression (1) nausea (1) 0.20 80% reduction apre-implementation group received customary care as determined by anesthesia provider. post-implementation group received preoperative gabapentin and iv acetaminophen in addition to typical customary care decided by anesthesia provider. numerous relationships were observed between variables. morphine equivalents administered in the pacu and time in the pacu displayed a large, positive correlation [rs (48) = 0.528, p<0.000]. additionally, pain on admission and time in the pacu had a moderate, positive association [rs (48)= 0.349, p<0.01]. notably, the largest association with opioid-related adverse events (a small negative correlation) was with whether the patient received the preoperative analgesic regimen. administration of the preoperative analgesic regimen was associated with fewer opioid-related adverse events [rs (48) = -0.25, p=0.085]. statistical significance was not achieved for any inferential statistical test. this was likely due to the small sample of the quality improvement project. given a medium effect size (0.50), alpha set to 0.05, and power set to 0.80, a sample size of 75 would have been required in each group to achieve statistical significance for a two-tailed independent t-test. this would have necessitated 15 to 30 months to complete at the author’s institution. given that this was a quality improvement study, utilizing analgesics already supported by category a1 evidence,16 a shorter duration was preferred to achieve results consistent with the literature and to assess successful implementation of the project. discussion summary prior to this quality improvement project, there were no existing preemptive analgesic protocols in this author’s department and concerns existed that staff resistance may lead to difficulty with implementation. however, this preemptive, multimodal project was well received by all anesthesia providers. the strength of this project was the simplicity with which the regimen was instituted coupled with the documented efficacy of the analgesic regimen. postoperative opioid use and opioidrelated adverse events showed marked improvement, and all other primary objectives trended positively. minor changes were made to the project during implementation. one change related to the timing of the gabapentin as patients arrived at the operating room holding area. initially, patients were to receive the oral gabapentin upon arrival to the holding area. however, administration at this time resulted in the patients receiving the gabapentin 2 to 3 hours early for 2 of the first 5 patients in the post-implementation group. this was identified early and overcome by holding the gabapentin until physical confirmation of the previous operation nearing completion, as evidenced by the onset of suture closure of the surgical incisions. despite the minor adjustment to protocol, the project was successful and met its intended goals. significant improvements were noted by the large decrease in narcotic analgesics administered in the pacu, the decreased time spent by patients in the pacu, and the substantial decrease in opioid-related adverse events. relation to other evidence the project’s outcomes were consistent with the evidence appraised in the literature. gabapentin and its effect on pain and pain-related outcomes have been studied extensively for both operative and nonoperative pain. gabapentin, although similar in structure to gamma-aminobutyric acid (gaba), does not attach to the gabaa or gabab receptors, but instead is an alpha-2 delta calcium channel blocker believed to exert its effect by decreasing neurotransmitter release.23 gabapentin has a high volume of distribution (60 l in healthy individuals) and achieves its maximum plasma concentration (cmax) in 3 hours. gabapentin is unbound to proteins and is cleared almost exclusively by the kidneys with an elimination half-life of 4.8-8.7 anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 39 hours.23 when administered 1 to 2 hours before hysterectomy, vaginal or abdominal, studies have reported a decrease in morphine consumption,24-31 a decrease in pain scores,24-26,28,31 and a decrease in nausea or vomiting.24,26,29 although oral and rectal forms of acetaminophen have been available for over a century, the iv formulation is relatively new. iv acetaminophen was introduced in europe in 2002 but was not approved for use in the united states until 2010, under the trade name ofirmev (mallinckrodt pharmaceuticals). iv acetaminophen is now found in many hospitals around the world.22 the exact mechanism of iv acetaminophen is unknown but it has been shown to exert its action both centrally and peripherally, possibly altering the action on nmda, cox, and/ or serotonergic receptors.23 the cmax for iv acetaminophen is twice that of oral administration, achieved in 15 minutes, and iv acetaminophen has a duration of action of approximately 4 to 6 hours. iv acetaminophen has a volume of distribution of 69.2 l in healthy volunteers and does not bind extensively to proteins. it is metabolized extensively by the liver and has an elimination half-life of 2.7 hours.32 preemptive iv acetaminophen utilized as an adjunct to pain management for hysterectomy has been reported to decrease narcotic requirements,33,34 decrease pain scores,33 and decrease opioid-related adverse events.33,34 when preemptive iv acetaminophen and gabapentin are combined, the decrease in narcotics and pain scores is significantly greater than placebo as well as when either drug is used independently.35,36 limitations with only 25 patients in each group, a greater number of disparities in practice among anesthesia providers for one group than the other may have affected the analgesic outcomes. for example, anesthesia providers interpret pain during surgery and treat it accordingly. some providers may block the sympathetic response with nonanalgesic sympatholytics rather than analgesics, potentially leading to increased pain for patients while in the pacu until appropriate analgesia is achieved. the lack of controls regarding intraoperative actions by anesthesia providers was ultimately viewed as a strength of this quality improvement project, however, because altering individual anesthesia provider preferences would change the overall ability to determine this regimen’s application in the author’s setting. chronic pain is a common indication for hysterectomy and provides a unique postoperative pain management challenge owing to nervous system sensitization or tolerance to analgesics.37 this factor was identified prior to implementation and comparisons were conducted to ensure homogeneity between groups. however, it was discovered after implementation had begun that the source for these data, the anesthesia preoperative assessment, was inconsistent with the surgeons’ history and physical examinations. therefore, many of those with chronic pain may not have been identified. it is possible that with only 25 patients in each group, one group may have included a statistically significantly greater number of patients with chronic pain, although this is unlikely. the likelihood that observed outcomes would wane over time was considered possible if anesthesia providers abandoned the preemptive, multimodal nature of this intervention. attempts were made by the author to maintain compliance over time. during dissemination of the study results to the anesthesia department, time for discussion was afforded to allow the crnas and anesthesiologists the opportunity to provide critiques and identify barriers not detected by the author. encouragingly, the anesthesia staff expressed an overwhelmingly positive attitude, and further plans have been made to expand on the success of this project. ideally, the author would have observed the continued use of preemptive, multimodal pain management regimens that followed the formal implementation group of this project. unfortunately, there was no additional time to achieve this outcome. interpretation this quality improvement project resulted in clinically significant improvements in practice outcomes with the implementation of minor alterations of practice. despite the effectiveness of the instituted regimen, some modifications to future regimens could be considered, including the addition of nonselective cox inhibitors, selective cox-2 inhibitors, and/or alpha-2 antagonists, among other minor adaptations. this project instituted a fixed regimen for all women having a hysterectomy and did not allow for flexibility by the anesthesia provider to alter the gabapentin dose or substitute a preemptive analgesic, as they might have otherwise. ideally, analgesic regimens should be individually tailored for patients according to the anesthesia provider’s clinical expertise. hospital-costing practices can be highly variable and complex with differing methodologies resulting in difficulty performing a cost analysis for this analgesic regimen. moreover, a cost comparison was not an intended outcome measure for this quality improvement project. however, a simple exploration of economic benefit was performed. for the author’s institution, the direct cost of the addition of the analgesic regimen of gabapentin and iv acetaminophen (ofirmev) was $12.39, $0.56 per 600-mg dose of gabapentin and $11.83 per 1000-mg dose of iv acetaminophen (ofirmev) (s blessing, a pangelinan, personal communication, april 20, 2016). given the modest cost of opioids and antiemetics, any financial benefit of the addition of gabapentin and iv acetaminophen (ofirmev) was not likely realized in drug cost-savings. rather, the savings were more likely observed in the avoidance of opioid-related adverse drug events and the time and activity costs that are associated with them. in this project, opioid-related adverse events were reduced from an incidence of 5 to 1 (table 3). oderda et al4 reported that for every opioid-related adverse event, there is additional $840 in hospital costs. thus, the small increase in costs for the regimen was quickly recovered. moreover, the cost of this regimen could be further reduced if the oral formulation of acetaminophen, costing $0.15 per 975mg dose (s blessing, a pangelinan, personal communication, april 20, 2016), was administered in place of the iv formulation. although there is good pharmacokinetic theory supporting the claim that iv acetaminophen would provide better analgesia,21,22 there is limited evidence and much debate whether iv acetaminophen actually leads to better analgesic outcomes. currently, multiple clinical trials are ongoing to compare the 2 formulations and answer these clinical questions.38 anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 40 conclusions in summary, the analgesic regimen was easily implemented, increased the incidence of multimodal regimens, and improved analgesic outcomes for women undergoing hysterectomy at the author’s institution. this regimen is easily modifiable, potentially cost-saving, and compatible for implementation with other patient populations. future quality improvement projects of this kind would expand the regimen to other surgical populations and provide more flexibility in the analgesic regimen, particularly with regard to using additional preemptive analgesics, substituting analgesics when deemed appropriate, and increasing or decreasing doses as needed. furthermore, future projects could thoroughly conduct a formal time-driven, activity-based costing algorithm to further explore the potential for cost-savings. summary of key points -easy-to-implement, evidence-based regimen consisting of preoperative gabapentin and iv acetaminophen -reduced opioid consumption, pain scores, opioid-related adverse events, and time in the pacu -cost-effective, easily modifiable, and appropriate to multiple populations across numerous surgical operations acknowledgments: the primary author was a duke university doctor of nursing practice student throughout the qi project. the authors would like to thank julie a. thompson, phd, duke university school of nursing, for her statistical consultation throughout the creation of this manuscript. the authors would also like to thank the incredible leadership and anesthesia staff of william beaumont army medical center for their commitment to evidence-based medicine and best practices. disclaimer: the views expressed in this manuscript are those of the author(s) and do not reflect the official policy of william beaumont army medical center, the department of the army, or the united states government. references 1. national health center for health statistics. inpatient surgery. centers for disease control and prevention website. http:// www.cdc.gov/nchs/fastats/inpatient-surgery.htm. last updated july 6, 2016. accessed july 7, 2016. 2. national health center for health statistics. u.s. outpatient surgeries on the rise. centers for disease control and prevention website. http://www.cdc.gov/nchs/pressroom/09newsreleases/outpatientsurgeries.htm. published january 28, 2009. accessed july 7, 2016. 3. apfelbaum jl, chen c, mehta ss, gan tj. postoperative pain experience: results from a national survey suggest postoperative pain continues to be undermanaged. anesth analg. 2003;97(2):534-540. http://dx.doi.org/10.1213/01. ane.0000068822.10113.9e. 4. oderda gm, evans rs, lloyd j, et al. cost of opioid-related adverse drug events in surgical patients. j pain symptom manage. 2003;25:276-83. http://dx.doi.org/10.1016/s0885-3924(02)00691-7. 5. white pf, kehlet h. improving postoperative pain management: what are the unresolved issues? anesthesiology. 2010;112(1):220-225. http://dx.doi.org/10.1097/aln.0b013e3181c6316e. 6. kaiser family foundation. hospital adjusted expenses per inpatient day, 2011. http://kff.org/other/state-indicator/expensesper-inpatient-day/. accessed march 23, 2014. 7. brandsborg b, nikolajsen l, hansen ct, kehlet h, jensen ts. risk factors for chronic pain after hysterectomy: a nationwide questionnaire and database study. anesthesiology. 2007;106(5):1003-1012. http://dx.doi.org/10.1097/01. anes.0000265161.39932.e8. 8. gaskin dj, richard p. the economic costs of pain in the united states. j pain. 2012;13(8):715-724. http://dx.doi.org/10.1016/j. jpain.2012.03.009. 9. chandrakantan a, glass ps. multimodal therapies for postoperative nausea and vomiting, and pain. br j anaesth. 2011;107(suppl 1):i27-i40. http://dx.doi.org/10.1093/bja/aer358. 10. azari l, santoso jt, osborne se. optimal pain management in total abdominal hysterectomy. obstet gynecol surv. 2013;68(3):215-227. http://dx.doi.org/10.1097/ogx.0b013e31827f5119. 11. nieboer te, johnson n, lethaby a, et al. surgical approach to hysterectomy for benign gynaecological disease. cochrane database syst rev. 2009 jul 8;(3):cd003677. 10.1002/14651858.cd003677.pub4. 12. muzii l, basile s, zupi e, et al. laparoscopic-assisted vaginal hysterectomy versus minilaparotomy hysterectomy: a prospective, randomized, multicenter study. j minim invasive gynecol. 2007;14(5):610-615. http://dx.doi.org/10.1016/j.jmig.2007.05.012. 13. marana r, busacca m, zupi e, garcea n, paparella p, catalano gf. laparoscopically assisted vaginal hysterectomy versus total abdominal hysterectomy: a prospective, randomized, multicenter study. am j obstet gynecol. 1999;180(2 pt 1):270-275. http:// dx.doi.org/10.1016/s0002-9378(99)70199-7. 14. elvir-lazo ol, white pf. postoperative pain management after ambulatory surgery: role of multimodal analgesia. anesthesiol clin. 2010 jun;28(2):217-24. doi: .02.011. 10.1016/j.anclin.2010.02.011. 15. american association of nurse anesthetists. standards for nurse anesthesia practice, 2013. www.aana.com/resources2/ professionalpractice/documents/ppm%20standards%20for%20nurse%20anesthesia%20practice.pdf. accessed september 2, 2014. 16. american society of anesthesiologists task force on acute pain management. practice guidelines for acute pain management in the perioperative setting: an updated report by the american society of anesthesiologists task force on acute pain management. anesthesiology. 2012;116(2):248-273. http://dx.doi.org/10.1097/aln.0b013e31823c1030. 17. grape s, tramèr mr. do we need preemptive analgesia for the treatment of postoperative pain? best pract res clin anaesthesiol. 2007;21(1):51-63. http://dx.doi.org/10.1016/j.bpa.2006.11.004. 18. ferreira-valente ma, pais-ribeiro jl, jensen mp. validity of four pain intensity rating scales. pain. 2011;152(10):2399-2404. http://dx.doi.org/10.1016/j.pain.2011.07.005. 19. united states code of federal regulations. definitions. 2010. title 32, volume 2, chapter 1, section 219-102, p. 428. http:// www.ecfr.gov/cgi-bin/text-idx?sid=d0cd93963ee90170 b994ae5e29b206de&node=se32.2.219_1102&rgn=div8. accessed september 2, 2014. 20. tricare. eligibility. http://www.tricare.mil/eligibility. accessed september 2, 2014. 21. van der westhuizen j, kuo py, reed pw, holder k. randomised controlled trial comparing oral and intravenous paracetamol (acetaminophen) plasma levels when given as preoperative analgesia. anaesth intensive care. 2011;39(2):242-246. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 41 22. singla nk, parulan c, samson r, et al. plasma and cerebrospinal fluid pharmacokinetic parameters after single-dose administration of intravenous, oral, or rectal acetaminophen. pain pract. 2012;12(7):523-532. http://dx.doi.org/10.1111/ j.1533-2500.2012.00556.x. 23. chang cy, challa ck, shah j, eloy jd. gabapentin in acute postoperative pain management. biomed res int. 2014;204:631756. 24. ajori l, nazari l, mazloomfard mm, amiri z. effects of gabapentin on postoperative pain, nausea and vomiting after abdominal hysterectomy: a double blind randomized clinical trial. arch gynecol obstet. 2012;285(3):677-682. http://dx.doi. org/10.1007/s00404-011-2023-6. 25. behdad s, ayatollahi v, bafghi at, tezerjani md, abrishamkar m. effect of gabapentin on postoperative pain and operation complications: a randomized placebo controlled trial. west indian med j. 2012;61(2):128-133. 26. frouzanfard f, fazel mr, abolhasani a, fakharian e, mousavi g, moravveji a. effects of gabapentin on pain and opioid consumption after abdominal hysterectomy. pain res manag. 2013;18(2):94-96. http://dx.doi.org/10.1155/2013/787401. 27. ghai a, gupta m, hooda s, singla d, wadhera r. a randomized controlled trial to compare pregabalin with gabapentin for postoperative pain in abdominal hysterectomy. saudi j anaesth. 2011;5(3):252-257. http://dx.doi.org/10.4103/1658354x.84097. 28. khan ma, siddiqi kj, aqeel m. effect of gabapentin on opioid requirements in patients undergoing total abdominal hysterectomy. anaesth pain intensive care. 2013;17(2):131-135. 29. rorarius mg, mennander s, suominen p, et al. gabapentin for the prevention of postoperative pain after vaginal hysterectomy. pain. 2004;110(1-2):175-181. http://dx.doi.org/10.1016/j.pain.2004.03.023. 30. sen h, sizlan a, yanarates o, et al. a comparison of gabapentin and ketamine in acute and chronic pain after hysterectomy. anesth analg. 2009;109(5):1645-1650. http://dx.doi.org/10.1213/ane.0b013e3181b65ea0. 31. turan a, karamanlioğlu b, memiş d, usar p, pamukçu z, türe m. the analgesic effects of gabapentin after total abdominal hysterectomy. anesth analg. 2004;98(5):1370-1373. table of contents. http://dx.doi.org/10.1213/01.ane.0000108964.70485. b2. 32. duggan st, scott lj. intravenous paracetamol (acetaminophen). drugs. 2009;69(1):101-113. http://dx.doi. org/10.2165/00003495-200969010-00007. 33. arici s, gurbet a, türker g, yavaşcaoğlu b, sahin s. preemptive analgesic effects of intravenous paracetamol in total abdominal hysterectomy. agri. 2009;21(2):54-61. 34. moon ye, lee yk, lee j, moon de. the effects of preoperative intravenous acetaminophen in patients undergoing abdominal hysterectomy. arch gynecol obstet. 2011;284(6):1455-1460. http://dx.doi.org/10.1007/s00404-011-1860-7. 35. durmus m, kadir but a, saricicek v, ilksen toprak h, ozcan ersoy m. the post-operative analgesic effects of a combination of gabapentin and paracetamol in patients undergoing abdominal hysterectomy: a randomized clinical trial. acta anaesthesiol scand. 2007;51(3):299-304. http://dx.doi.org/10.1111/j.1399-6576.2006.01237.x. 36. syal k, goma m, dogra rk, ohri a, gupta ak, goel a. “protective premedication”: a comparative study of acetaminophen, gabapentin and combination of acetaminophen with gabapentin for post-operative analgesia. j anaesthesiol clin pharmacol. 2010;26(4):531-536. 37. vadivelu n, mitra s, narayan d. recent advances in postoperative pain management. yale j biol med. 2010;83(1):11-25. 38. us national institutes of health. oral acetaminophen, iv acetaminophen [search results]. clinicaltrials. gov website. https://clinicaltrials.gov/ct2/results?term=oral%20acetaminophen%20iv%20 acetaminophen&search=search. accessed february 3, 2015. anesthesia ejournal www.anesthesiaejournal.com volume 4 issue 1 2016 page 42 volume 8no. 7 2020 educated hand publishing llc “the science behind the art” volume 8 no. 7 2020 anesthesia ejournal online issn 2333-2611 page 21 mobile anesthesia applications as point-of-care tools for crnas in clinical practice bevin rene strickland, dnp, rn, crna affiliation: carolina anesthesiology, p.a., high point medical center, high point nc daniel m. strickland, ms, md, facog affiliation: medical director, stepping stone of nc, boone, nc funding/conflict of interest disclosure: none keywords: mobile apps; health care apps; anesthesia apps; mobile technology; crna; nurse anesthesia; point-of-care tools; poc tool abstract the practice of anesthesia requires knowledge of procedures, patient conditions, comorbidities, and medications, as well as the ability to continually assess and respond to the patient’s status. the use of mobile anesthesia applications (apps) has become increasingly common among certified registered nurse anesthetists (crnas) to provide immediate access to current information regarding anesthesia administration and to support optimal patient care. the purpose of this study was to assess the use of mobile anesthesia apps used by crnas as point-of-care (poc) tools in their anesthesia practice. data reported was collected from a survey designed to sample crnas who have been in practice for three years or less (“recent” graduates) and who utilize mobile anesthesia apps. the survey was offered to members of a facebook group called crnas and srnas. a total of 160 practicing crnas completed the survey and reported the ways they currently use a mobile anesthesia app. users report benefits to practice from using these apps. this data should be encouraging to the developers of mobile health care apps and a motivating factor for more practitioners to utilize them. introduction the practice of administering anesthesia is in a continuous state of growth and change, which presents a challenge to both the novice, as well as the experienced practitioner. mobile apps, specific to the practice of anesthesia, can provide immediate access to up-to-date information on techniques, specific patient populations, medications, surgical procedures, and patient conditions, as well as other tools that can assist practitioners in optimal management of cases1,2,3,4,5. such technologies have been successful in many areas of health care practice and can play an important role in reducing errors and improving patient outcomes6,7,8,9. the most commonly used apps by anesthesia providers (anesthesiologists, crnas) include epocrates, followed by a combination of vargo anesthesia, medscape and blockbuddy8. aej educated hand publishing llc “the science behind the art” volume 8 no. 7 2020 anesthesia ejournal online issn 2333-2611 page 22 methodology the purpose of the project was to examine the use of mobile apps by crnas in their practice. a literature review was conducted using cinahl, cochrane library, pmc, pubmed, and researchgate databases. search terms used for the review included “health care apps”, “mobile anesthesia apps”, “mobile apps as point-of-care tools”, “common areas in anesthesia”, “technology to improve health care”, “mobile devices in health care”, “smartphones in health care”, and “mobile apps to decrease perioperative errors”. a survey (appendix a) was developed using the technology acceptance model (tam), a theoretical framework that explains how a user’s perception of usefulness and ease of use will determine whether or not they utilize available technology2. volunteers were recruited from a private facebook group named “crnas and srnas”, consisting of practitioners who use mobile anesthesia apps and are currently in practice with 3 years, or less, of experience. a group post explained the purpose of the survey consisting of 11 questions that included multiple-choice, fill-in-the blanks, and yes/no answers. years of experience, clinical practice setting(s), specific mobile app(s) used, and opinions about standardization of mobile apps were also elicited. data collection took place from june 13, 2019 through june 29, 2019, with 169 participants: 9 did not use apps, and 160 completed the survey. 159 participants responded to the question regarding which specific mobile app(s) they use. 96.2% use vargo anesthesia. other ancillary apps included block buddy, asra coags, safelocal, heartpedia, uptodate, micromedex, mednax csa, sanford guide, pedi anesthesia, epocrates, medscape, medex, pedi stat, as well as anesthesia drug handbook and textbook apps. results figure 1. years of experience as a crna. figure 2. clinical practice setting. figure 3. length of time using a mobile anesthesia app as a practicing crna figure 4. data referenced using mobile health care apps. figure 5. purpose of using mobile anesthesia apps. figure 6. when crnas are most likely to use a mobile anesthesia app. figure 7. impact of using mobile anesthesia apps on crna practice. figure 8. opinions on the standardization of mobile anesthesia by hospitals (n=160). figure 9. mobile anesthesia apps positively or negatively contributing to crna practice. discussion it has been opined that mobile apps provide ready access to necessary information10,11 that would otherwise only be available in textbooks, but there is a lingering belief that mobile devices present a distraction from patient care or even that the use of mobile devices in a patient care setting is unprofessional12. even in this time of a computer in every pocket, some voice concern that they do not have the skills or knowledge to effectively use them. but considering that anesthesia is one of the most technology-intensive fields in healthcare practice, those attitudes are rapidly becoming anachronistic. this study did not address such issues, nor was it intended to do so. but the data do demonstrate that the willingness of recent crnas to use mobile apps as poc tools is largely dependent on their ability to recognize the usefulness (and hopefully the limitations) of these apps in the practice setting. as a caveat, although many anesthesia providers regularly use mobile health care apps, their employers may not explicitly authorize, monitor, or provide oversight for their use, and such issues should be broached before using them in the or. a follow-up study would address usage and attitudes among more experienced crnas to evaluate the evolving needs for access to data before, during, and after procedures requiring anesthesia. appendix a. survey questions how many years have you been in practice as a crna? in what clinical setting do you practice as a crna? do you currently use a mobile anesthesia app for a resource in your practice as a crna? what mobile anesthesia app(s) do you use? approximately how long have you used a mobile anesthesia app as a practicing crna? what categories best describe the data that you reference from your mobile anesthesia app? for what purpose do you use your anesthesia app? when are you most likely to use your anesthesia app? complete the following statement in the best way possible in reference to your use of a mobile anesthesia application (you may choose more than one selection). do you think hospitals should standardize the use of a mobile anesthesia app(s) for their anesthesia providers, including paying for any fees to support use of the app(s)? do you think mobile anesthesia apps are a positive or a negative contribution to your profession? educated hand publishing llc “the science behind the art” volume 8 no. 7 2020 anesthesia ejournal online issn 2333-2611 page 23 references 1. aungst td, clauson ka, misra s, lewis tl, & husain i. how to identify, assess, and utilise mobile medical applications in clinical practice. international journal of clinical practice. 2014; 68(2): 155-162. doi:10.1111/ijcp.12375. 2. davis f. perceived usefulness, perceived ease of use, and user acceptance of information technology. mis quarterly. 1989;13(3), 319-340. doi.10.2307/249008. 3. monroe ks, evans ma, mukkamala sg, et al. moving anesthesiology educational resources to the point of care: experience with a pediatric anesthesia mobile app. korean journal of anesthesiology. 2018; 71(3), 192. doi:10.4097/kja.d.18.00014. 4. simpao af, galvez ja, cannesson m. should we fear computers or the lack of them? technology, digital quality improvement, and the care redesign process. anesthesiology. 2017; 126:369-370. doi.10.1097/aln.0000000000001517. 5. vadhanan p, adinarayanan s. handheld devices and informatics in anesthesia. anaesth pain & intensive care. 2016;20(2): 201208. 6. baumann d, dibbern n, sehner s, zöllner c, reip w, & kubitz jc. validation of a mobile app for reducing errors of administration of medications in an emergency. journal of clinical monitoring and computing. 2019;33(3):531-539. 7. green ms, mathew jj, venkatesh ag, green p, tariq r. utilization of smartphone applications by anesthesia providers. anesthesiology research and practice. 2018; 1–10. doi.10.1155/2018/8694357. 8. ventola cl. mobile devices and apps for health care professionals: uses and benefits. pharmacy and therapeutics. 2014;39(5):356. 9. dulat j, reeves m. attitudes and beliefs among anesthesia providers regarding smartphone use for intraoperative anesthetic management. 2018. doi:10.1155/2018/8694357 10. gomeyac sa. use of mobile phones in the operating room: a literature review accessed june 6, 2020. https://www.theseus.fi/ bitstream/handle/10024/136564/gomeyac_shielou.pdf?sequence=1&isallowed=y. 11. ferris ma. reference resource usage among nurse anesthetists: a survey. aana journal. 2018;86(4):299-309. attri jp, khetarpal r., chatrath v, kaur, j. concerns about the usage of smartphones in the operating room and critical care scenario. saudi journal of anaesthesia. 2016; 10(1):87–94. https://doi.org/10.4103/1658-354x.169483. about the authors dr. bevin strickland is a recent graduate from university of north carolina, greensboro nurse anesthesia program. she is currently practicing with carolina anesthesia, serving wake forest baptist health, high point medical center, nc. dr. daniel strickland is medical director of wj medical associates where he serves as collaborating physician for a group of advanced practice providers in family medicine, pediatrics, and occupational health.  he is also  medical director for stepping stone of north carolina, a state approved opioid treatment program. https://www.doximity.com/pub/daniel-strickland-md educated hand publishing llc “the science behind the art” volume 8 no. 7 2020 anesthesia ejournal online issn 2333-2611 page 24 volume 8no. 1 2020 educated hand publishing llc “the science behind the art” volume 8 no. 1 2020 anesthesia ejournal online issn 2333-2611 page 1 noise pollution in the operating room: student registered nurse anesthetist education: reduction strategies and tools tyler davis-sandfoss, dnp, crna rachel smith-steinert, dnp, crna affiliation: university of cincinnati funding/conflict of interest disclosure: none keywords: anesthesia; noise; noise pollution; operating room; occupational safety abstract noise pollution in the operating room (or) poses a safety concern to both patients and providers. sound levels often exceed recommended standards set forth by the national institute for occupational safety and health (niosh) and the occupational safety and health administration (osha). the purpose of this project was to examine current evidence and implement education for student registered nurse anesthetists (srnas) regarding noise pollution in the or. a pre-test and post-test methodology was utilized to assess the efficacy of the education module. results generated from the education module illustrated a knowledge deficient in srnas pertaining to noise reduction, cognitive demand, and attention allocation during the delivery of an anesthetic in the or. average post-test scores were found to have a statistically higher average compared to the average pre-test scores (p < 0.001). noise pollution has been shown to be a complex, multifactorial problem. emphasis should be placed on sustaining and integrating noise reduction education into curriculum schemas of nurse anesthesia programs. aej background noise pollution in the operating room (or) poses a significant threat to both patients and or staff during the intraoperative period. evidence shows that operating room noise levels often exceed the standards set by the national institute for occupational safety and health (niosh) and the occupational safety and health administration (osha). 1, 2, 3 katz and englemann highlight the magnitude of noise levels, suggesting levels in the or are greater than those generated from lawn mowers or passing trucks on a major highway. 4, 5 currently, osha suggests limiting exposure to 95 decibels in four hours compared to niosh suggesting exposure limits of 95 decibels to one hour. 1 routine exposure to noise pollution can predispose or staff to increased chances of hearing loss, cardiovascular disease, cognitive stress, and hinders one’s ability to provide clear communication with other team members. 6, 11 the purpose of this project was to construct and evaluate a noise pollution education module for student registered nurse anesthetists (srnas) with the goals of knowledge attainment and personal reflection pertaining to current practices. future ramifications of this project could have an impact on improving overall patient outcomes and provider safety. operating room staff work in a fast paced, high acuity, stressful environment. during the intra-operative time period, care providers must remain vigilant, as their work requires critical thinking and a tremendous amount of responsibility. noise pollution presents a serious challenge in this setting. interdisciplinary collaboration to achieve decreased noise levels and improve patient outcomes is essential. investigation of current evidence identified initiatives such as the national institute for occupational safety and health (niosh) standards set forth in conjunction with the centers for disease control (cdc). 8 the cdc asserts, “the mission of the niosh hearing loss prevention program is to provide national and world leadership to reduce the prevalence of occupational hearing loss.” 8 emphasis on noise pollution and provider distraction has also been examined by the anesthesia patient safety foundation (apsf) recommending elimination of unnecessary clinical distractions, modulating unavoidable distractions, minimizing avoidable distractions, and reducing environmental noise.” 9,10 multiple sources of noise exist during perioperative care. staff behaviors, clinical practices, and or traffic in and out of the operating suite contribute to noise pollution. patient monitors and associated alarms, as well as surgical and anesthesia equipment, all contribute to a significant increase in noise pollution. 1, 3, 5 a loud environment not only creates an occupational hazard or distraction but can negatively affect care delivery which may ultimately result in patient harm. in addition to affecting staff performance, exposure to high noise levels can be harmful to patients by triggering physiologic changes like tachycardia, hypertension, oxygen desaturation, and laryngospasm. 6, 7 methods literature search pubmed, cinahl and scopus databases were searched using key words: noise, noise pollution, operating room, anesthesia, occupational safety. systematic reviews, randomized and nonrandomized controlled trials, cohort studies, case studies, qualitative studies, and expert opinions were all considered. a total of 117 articles were retrieved, of which thirty-seven were included for review. educational intervention this srna education module was constructed with consideration of the joint commission’s 2018 national hospital patient safety goals. institutional review board (irb) approval was deemed exempt for non-human subjects from the academic medical center. an in-depth analysis of current initiatives in the united states of america were reviewed to establish the need for this quality improvement project. the cdc hearing loss prevention program, the joint commission’s 2017 hospital patient safety goals and the anesthesia patient safety foundation (apsf) conference reviewing distractions in the anesthesia work environment, were utilized to establish project need and construct the education module. 8, 9, 10 the noise pollution education content was not in the basic curriculum or nurse anesthesia traineeship programs evaluated. furthermore, regulatory bodies have mandated institutions to protect employees from occupational hazards and that employees understand what occupational hazards pose a threat to their health. student recruitment was elicited via email and participation was voluntary. forty students participated in two education modules and lectures focusing on noise pollution. the education module for srnas on noise pollution was constructed to provide learners with a comprehensive summary of noise pollution, factors contributing to excessive noise, and the effects of noise pollution on patients and providers in the or. an oral presentation was utilized to provide learners information on the characteristics of sound waves and how that leads to the production of noise. the primary sources of noise from monitors, alarms, equipment, and staff behavior were reviewed. 1, 4 several tools and strategies to ameliorate noise pollution were provided including the use of noise measuring phone applications for reference sound levels and how to facilitate interdisciplinary huddles to address noise pollution. actions to eliminate or minimizing unnecessary noise like music and suction were discussed. evaluation method a pre-test and post-test methodology was utilized to assess effectiveness of the educational content delivery (figure 1). ten minutes were allotted to complete a pre-test, fifteen minutes for delivery of educational content, and ten minutes for posttest completion. students were provided an open forum session following delivery and completion of the education module to ask more detailed questions or express concerns regarding the content. scores were analyzed using a t-test for paired data. results the aim of this quality improvement education project was to assess srna awareness of noise pollution in the operating room and the associated consequences. the null hypothesis stated: there will not be a statistically significant difference between educated hand publishing llc “the science behind the art” volume 8 no. 1 2020 anesthesia ejournal online issn 2333-2611 page 2 pre-test scores and post-test scores. the pre-tests and post-tests included 8 multiple-choice questions and two open-response questions (figure 1). answers to questions were marked as correct or incorrect. the mean average pre-test score was 60% compared to the mean average post-test mean score of 90%. a 2-tailed t-test for paired data was completed and revealed the observed difference (30%) was statistically significant (p<0.001). assumptions for the t-test for paired data included continuous, interval/ratio level data and normality of data distribution. after analyzing data generated from the t-test demonstrating a statistically significant difference (30%) between the average pre-test scores and the average post-test scores, the decision was made to reject the null hypothesis. results generated from the education module illustrated a knowledge deficient pertaining to noise pollution, cognitive demand, and attention allocation when providing anesthesia. the education module appeared effective in shedding light on noise pollution in the ora true knowledge deficit of srnas. the open forum discussion section revealed that over half the students were, “not concerned with noise” (n=29). four stated they were, “sometimes concerned,” and seven stated they “were concerned.” however, 100% of students would change future practice after completing the education modules. discussion noise pollution in the operating room has been an overlooked, but significant environmental and occupational hazard for both patients and providers. there has been a large body of evidence to support that sound levels in the operating room often exceed safe levels 1, 2, 3, 13 special attention should be given to the current initiatives in place that acknowledge noise pollution as a significant threat. this project aim was to disseminate the current body of knowledge pertaining to noise pollution and provide suggestions to decrease or eliminate noise. even if the findings had not been statistically significant, there was a profound argument that this project was clinically important in that interdisciplinary practice changes may yielded improved outcomes. van pelt stated, “distractions in the perioperative work environment can adversely affect vigilance, situational awareness, and the ability to respond promptly to changes in the patient’s condition and pose a risk to patient safety.” 10 one may assert that in order to achieve a system wide culture change, early delivery of formal education pertaining to environmental and occupational hazards should be employed. this initiative could improve patient safety and patient and provider satisfaction. limitations the main limitation for this project was a small convenience sample from one nurse anesthesia program for the educational content delivered. future projects should expand educational content to other or professionals (eg, anesthesia providers, or staff ). furthermore, this quality improvement project was limited by the time constraint allotted for implementation. students completed the pre-test, education module, and post-test in one session. follow-up six months post-education would be beneficial to assess retention. a follow-up survey would assist in collection of data regarding practice changes have and any other perceived beneficial changes. conclusion excessive noise in the operating room poses a significant threat to both patients and providers. noise pollution strains an anesthesia providers’ cognitive ability to function and challenges attention allocation. interdisciplinary teams should be formed to identify, implement, and evaluate processes to decrease noise pollution in the operating room. it is imperative that ongoing assessment of interventions be conducted to ensure progress and augmentation of a therapeutic environment. although several national initiatives are in place to reduce noise, it is imperative the knowledge pertaining to noise reduction is disseminated, and effective interventions implemented to protect both providers and patients. about the authors tyler davis-sandfoss dnp, crna currently practices at ann & robert h. lurie children’s hospital of chicago with special interests in pediatric anesthesia and occupational safety for clinicians. rachel smith-steinert dnp, crna is the assistant program director at the university of cincinnati nurse anesthesia program and currently practices at the university of cincinnati medical center with special interests in nurse anesthesia education, grant writing, and collaboration with international schools of nursing. the authors currently are involved in ongoing quality improvement efforts addressing noise pollution and reduction in the operating room. educated hand publishing llc “the science behind the art” volume 8 no. 1 2020 anesthesia ejournal online issn 2333-2611 page 3 references 1. fritsch mh, chacko ce, patterson eb. operating room sound level hazards for patients and physicians. otol neurotol. 2010;31:715-721. 2. hogan lj, harvey rl. creating a culture of safety by reducing noise levels in the or. aorn j. 2015;102(4):410.e1-410.e7. doi:10.1016/j.aorn.08.005 3. mcneer rr, bennett cl, dudaryk r. intraoperative noise increases perceived task load and fatigue in anesthesiology residents: a simulation-based study. anesth analg. 2016;122:512-525. 4. katz jd. noise in the operating room. anesthesiology. 2014;121:894-898. 5. engelmann cr, neis jp, kirschbaum c, grote g, ure bm. a noise-reduction program in a pediatric operation theatre is associated with surgeon’s benefits and a reduced rate of complications: a prospective controlled clinical trial. ann surg. 2014;259:1025-1033. 6. kerns e, masterson ea, themann cl, calvert gm. cardiovascular conditions, hearing difficulty, and occupational noise exposure within us industries and occupations. am j ind med. 2018;61:477-491. 7. antonucci, r, annalisa p, and vassilios f. the infant incubator in the neonatal intensive care unit: unresolved issues and future developments, journal of perinatal medicine. 2009;37(6): 587-598. doi:10.1515/jpm.2009.109 8. cdc niosh program portfolio: hearing loss prevention: program description. cdc website. https://www.cdc.gov/niosh/ programs/hlp/description.html. published 2018. accessed september 1, 2018. 9. 2018 hospital national patient safety goals. the joint commission website. https://www.jointcommission.org/assets/1/6/2018_ hap_npsg_goals_final.pdf. published 2018. accessed september 1, 2018. 10. van pelt m, weinger mb. distractions in the anesthesia work environment: impact on patient safety. anesth analg. 2017;125(1):347-350. doi:10.1213/ane.0000000000002139 11. ginsberg sh, pantin e, kraidin j, solina a, panjwani s, yang g. noise levels in modern operating rooms during surgery. j cardiothorac vasc anesth. 2013;27:528-530. 12. kulkarni e, abdallah y, hanseman d, & krishnan, d. how much noise is an oral and maxillofacial surgeon exposed to? journal of oral and maxillofacial surgery. 2018; 76(7): 1400-1403. educated hand publishing llc “the science behind the art” volume 8 no. 1 2020 anesthesia ejournal online issn 2333-2611 page 4 figure 1. educational module pre/post test 1. what is the average noise level in the operating room? a. 40 decibels b. 65 decibels c. 75 decibels d. 85 decibels e. 100 decibels 2. what organization regulates occupational noise exposure limits? a. national institute of occupational health and safety (niosh) b. american college of surgeons c. state associations (eg, ohio state health association) d. american association of nurse anesthetist 3. what is the maximum amount of noise exposure suggested by the above-mentioned regulatory body in an 8-hour period? a. 65 decibels b. 75 decibels c. 85 decibels d. 95 decibels e. 105 decibels 4. during noisy procedures, such as neurosurgical, orthopedic surgery, etc., what is the average noise level 40% of the time? a. 85 decibels b. 90 decibels c. 100 decibels d. 110 decibels 5. please list one organization that has established a task force or has been proactive in attempting to educate or staff on noise pollution. a. ______________________________________ ________________________________ 6. please list 3 variables that can be most easily manipulated to decrease noise pollution. a. ______________________________________ ________________________________ b. ______________________________________ ________________________________ c. ______________________________________ ________________________________ 7. please list 3 complications for patients associated with noise pollution in the operating room. a. ______________________________________ ________________________________ b. ______________________________________ ________________________________ c. ______________________________________ ________________________________ 8. please list 3 complications associated with noise pollution for providers. a. ______________________________________ ________________________________ b. ______________________________________ ________________________________ c. ______________________________________ ________________________________ educated hand publishing llc “the science behind the art” volume 8 no. 1 2020 anesthesia ejournal online issn 2333-2611 page 5 147-##_other-1025-1-11-20211222.jpg volume 9no. 4 2021 educated hand publishing llc “the science behind the art” volume 9 no.4 2021 anesthesia ejournal online issn 2333-2611 page 7 dexmedetomidine as an anesthetic adjunct in off-pump coronary artery bypass grafting: a case report dean vanek, bsn, rn affiliation: texas christian university grant/financial support: none biographical data: dean vanek is a registered nurse who is currently enrolled in texas christian university’s nurse anesthesia program. keywords: precedexâ, dexmedetomidine, off-pump coronary artery bypass grafting, alpha-2 agonist, cardiac surgery abstract this case report describes the implementation of a dexmedetomidine (precedexâ) infusion in a patient undergoing offpump coronary artery bypass grafting (opcabg). the focus of this case report is to analyze the impact dexmedetomidine has on perioperative opioid consumption, postoperative recovery, and hemodynamic effects that result. the addition of a dexmedetomidine infusion to the anesthetic plan of care in patients undergoing opcabg is supported by current literature. dexmedetomidine has many advantageous effects including analgesia, improvement in hemodynamic stability, and offers cardiac protection.1 the end result may lead to decreased narcotic requirements which may enable earlier extubation times and an overall decreased length of stay in the icu.1,2,3 intraoperative hemodynamic instability resulting from fluctuations in plasma levels of norepinephrine and epinephrine due to surgical stimulation are attenuated by dexmedetomidine due to the reduction in sympathetic output as a result of alpha-2 agonism.4 heart rate, mean arterial pressure, and systemic vascular resistance will be lower intraoperatively and postoperatively as a result.4,5 incidence rates of arrythmias occurring perioperatively such as atrial fibrillation, premature atrial contractions, premature ventricular contractions, and heart blocks are decreased with the use of dexmedetomidine.4,6 dexmedetomidine is shown to be a safe and useful anesthetic adjunct in patients undergoing opcabg. aej volume 8no. 4 2020 educated hand publishing llc “the science behind the art” volume 8 no.4 2020 anesthesia ejournal online issn 2333-2611 page 12 dexmedetomidine vs propofol for cardiopulmonary bypass jinah leazenby, bsn, rn, ccrn affiliation: texas christian university funding/conflict of interest disclosure: none keywords: cardiopulmonary bypass; dexmedetomidine; propofol; post-operative delirium; cerebral regional tissue oxygen saturation abstract propofol has been used as part of balanced anesthetic in cardiovascular surgery patients. dexmedetomidine is newer agent with multiple benefits and may be superior than propofol. a 68-year-old male with history of cad, gerd, t2dm, osa, was undergoing an elective coronary bypass graft surgery. the patient in this case report received dexmedetomidine infusion throughout the procedure as well as postoperatively. patient maintained cerebral oximetry > 50, did not suffer from arrythmias, his hemodynamic was stable, his icu course was short, and patient was also extubated in 2 hours after arrival to the unit. in addition, patient did not suffer from post-operative delirium. dexmedetomidine infusion during cardiac surgery may be superior to propofol infusion due to better prevention of ventricular arrythmia, hemodynamic stability, reducing length of mechanical ventilation and icu stay, and prevention of postoperative delirium. aej educated hand publishing llc “the science behind the art” volume 8 no.4 2020 anesthesia ejournal online issn 2333-2611 page 13 powerpoint template ©2009 texas christian university, center for instructional services. for educational use only. content is the property of the presenter and their resources. introduction • cardiovascular surgery poses increased risk for several complications including neurologic insult, postoperative dysrhythmias, cognitive disorders, myocardial ischemia, stroke, coma, heart block, acute renal failure, increased icu stay and prolonged mechanical ventilation.2-6 • dexmedetomidine has emerged in the maintenance of anesthesia during cardiac surgery as compared to propofol.2-6 purpose • this case study will review both agents to see if one is superior in providing better hemodynamic stability and patient outcomes while undergoing cardiopulmonary bypass. discussion • the patient in this case report received dexmedetomidine infusion throughout the procedure as well as postoperatively. due to the infusion, volatile anesthetic and opioid requirement were reduced. patient was also able to remain calm while on icu ventilator. • both propofol and dexmedetomidine preserve cerebral o2 saturation.2 the patient also maintained cerebral oximetry wnl (rsco2> 50) during this case. • dexmedetomidine does decrease ventricular dysrhythmias (eg pvc, vt) compared to propofol.3,6 the patient in this case report did not suffer from atrial or ventricular dysrhythmias. • dexmedetomidine has better hemodynamic stability.4 this was also true in this case study, patient maintained heart rate & bp during incision and sternotomy. • dexmedetomidine has been associated with reduced icu stay and decreased prolonged mechanical ventilation.4 the patient in this case study was extubated 2 hours after arrival to the unit without complications. • dexmedetomidine has been shown to be superior to other agents in preventing postoperative delirium (eg, midazolam, propofol, opioids, ketamine).5 the patient in this case study had normal neurologic exam preoperatively(a&ox4). 3-hour postoperative exam (1 hour post-extubation) was normal without evidence of delirium(a&ox4). dexmedetomidine vs propofol for cardiopulmonary bypass jinah leazenby, bsn, rn, ccrn texas christian university preanesthetic evaluation • 68-year-old, 85 kg, 180 cm, male cabg x3. • pmh: cad, gerd, t2dm, htn, osa, angina. • psh: l knee arthroplasty (sab -->without anesthesia complications) • cardiac cath report: lhc: 60% stenosis of prox. lad, 60% stenosis of ria, 70% stenosis of om1, echo: ef=60% without evidence of significant stenosis or regurgitation of valves. • pertinent labs: h/h: 14.0/42, plt 325 • pre-op vs: bp 140/87 mmhg, hr 85, o2sat 100%, rr 12, 36.8°c. • airway assessment: mp2, from of neck, tmd < 3fb, ulbt class i, >3fb mouth opening • anesthetic plan: geta with standard asa monitors, a line, central line, pa catheter, and cerebral saturation monitor. intraoperative anesthetic management • monitors: standard plus pre-induction a-line, pac, foley catheter. • induction: preoxygenation, iv induction: lidocaine 100 mg, fentanyl 100 mcg, etomidate 14 mg, propofol 50mg, and succinylcholine 130 mg, miller 2, grade i view, 8.0 ett. • maintenance: sevoflurane et 0.9-1.3% in a mixture of o2 1 l/min and dexmedetomidine infusion at 0.3mcg/kg/hr. norepinephrine infusion titrated for map goal of 70mmhg. 2 • on pump: dexmedetomidine 0.3mcg/kg/hr only • off pump: 250ml of 5% albumin and epinephrine infusion 0.01mcg/kg/min for ci goal 2.2. norepinephrine was continued at 0.3mcg/kg/min. 2300ml cellsaver blood administered. patient received total of 1000 mcg of fentanyl and 250mcg of sufentanil. plasma glucose maintained with insulin drip 1-3u/hour • cerebral oximetry monitoring wnl • case totals: 2000ml crystalloid, uop 1100 ml, ebl 100ml, 5 hours of anesthesia time. • patient remained intubated and transferred to icu on dexmedetomidine at 0.4mcg/kg/hr and norepinephrine at 0.03mcg/kg/min. postoperative evaluation • postop vs: bp 114/72 mmhg, hr 76, o2sat 100%, rr 16, and temperature 36.7°c. • the patient was extubated 2 hours post arrival to icu, remained free of complications and postoperative delirium. discharged to home on pod day 5. references 1.rathmell jp, rosow ce. intravenous sedatives and hypnotics. in: flood p, rathmell jp, shafer s. stoelting’s pharmacology & physiology in anesthetic practice. 5th ed. philadelphia, pa, wolters kluwer health.; 2015 2. metry aa, hussain ns, nakhla gm, ragaei mz, wahba rm. the effect of continuous propofol versus dexmedetomidine infusion on regional cerebral tissue oxygen saturation during cardiopulmonary bypass. rom j anaesth intensive care. 2019;26(1):17-23. 3. zhu z, zhou h, ni y, wu c, zhang c, ling x. can dexmedetomidine reduce atrial fibrillation after cardiac surgery? a systematic review and meta-analysis. drug des devel ther. 2018;12:521-531. 4. sheikh ta, dar ba, akhter n, ahmad n. a comparative study evaluating effects of intravenous sedation by dexmedetomidine and propofol on patient hemodynamics and postoperative outcomes in cardiac surgery. anesth essays res. 2018;12(2):555-560. 5. pieri m, de simone a, rose s, et al. trials focusing on prevention and treatment of delirium after cardiac surgery: a systematic review of randomized evidence. j cardiothorac vasc anesth. 2019. 6. ling x, zhou h, ni y, wu c, zhang c, zhu z. does dexmedetomidine have an antiarrhythmic effect on cardiac patients? a meta-analysis of randomized controlled trials. plos one. 2018;13(3):e0193303. 7. tufail sa, ahmad n, akhter n. comparative analysis of dexmedetomidine and propofol based sedation regimens on anaesthetic requirements in cardiac surgery with on-pump cardiopulmonary bypass. journal of clinical and diagnostic research. 2018. conclusion • dexmedetomidine infusion during cardiac surgery may be superior to propofol infusion in preventing ventricular dysrhythmias, providing better hemodynamic stability, reducing length of mechanical ventilation and icu stay, opioid and anesthetic sparing property, and preventing of postoperative delirium.1-7 pharmacology review dexmedetomidine propofol moa1 • potent alpha 2 adrenergic agonist (a2:a1 = 1620: 1) works by inhibiting pontine locus ceruleus causing decrease in sns activity and level of arousal causing sedation • gabaa agonist leading to decrease rate of dissociation of inhibitory neurotransmitter. (prolongs duration of hyperpolarization of cell membrane of chloride channel when gaba binds) cv1 • hypotension & bradycardia • hypotension & blunted tachycardic response to hypotension neuro1 • decrease cbf& no change in cmro2 • neuroprotective • decrease in cbf & cmro2 pharmacokinetic1 • highly protein bound • hepatic metabolism/kidney excretion • clearance of propofol from plasma > hepatic bf • hepatic metabolism/kidney excretion uses1 • attenuating hemodynamic response to intubation • decrease catecholamine level intraop • decrease periop requirement for inhaled anesthetic and opioid • potential anesthetic of choice for difficult airway, post-op shivering and post op sedation • induction of anesthesia • iv sedation • maintenance of anesthesia • antiemetic • antipruritic • anticonvulsant • attenuation of bronchoconstriction. literature review dexmedetomidine propofol cerebral tissue o2 sat2 • no significant decrease in rsco2 & mini-mental state exam • neuroprotective no significant decrease in rsco2 & mini-mental state exam neuroprotective hemodynamic stability4 • lower percentage of increase in hr, sbp, dbp was noted at skin incision and sternotomy • same pressor requirement • same pressor requirement length of stay in icu & length of mechanical ventilation4 • icu stay: 92 hours • post op ventilation: 5.9 hours • icu stay : 133.46 hours • post op ventilation: 8.6 hours post op arrythmia3,6 • not shown to reduce a fib • shown to reduce vt • not shown to reduce a fib post op delirium5 • systematic review of 56 articles showed dexmedetomidine to be superior pharmacologic agent in preventing postop delirium when compared to other pharmacologic agents such as propofol, ketamine, and opioids. introp opioid and anesthetic sparing property7 • 13.1 mg total required on average during intraop • lower mac of isoflurane requirement to maintain bis of 40-60 • 16.05mg total required on average during intraop 152-##_other-1027-1-11-20211222.jpg volume 9no. 5 2021 educated hand publishing llc “the science behind the art” volume 9 no.5 2021 anesthesia ejournal online issn 2333-2611 page 9 hypotension and bradycardia with sugammadex administration samantha nicholson, bsn, rn, ccrn affiliation: texas christian university grant/financial support: none biographical data: samantha nicholson is a registered nurse pursuing her dnp in nurse anesthesia at texas christian university keywords: sugammadex, bridion®, reversal agent, adverse drug reaction abstract the food and drug administration (fda) approved sugammadex for use as a reversal agent for nondepolarizing muscle relaxants.1 sugammadex binds free molecules of muscle relaxant, specifically rocuronium and vecuronium, resulting in a rapid offset of neuromuscular blockade.2 when compared to the use of neostigmine and glycopyrrolate for reversal, sugammadex has shown to be faster and able to provide reversal for deeper blockades.2 however, this new drug is not without risks. several case reports have been published describing profound hypotension and bradycardia after administration of sugammadex, with some cases progressing to asystole and death.1,3,4,5,6,7 this case report describes a patient who experienced a significant drop in cardiac output after being reversed with sugammadex. aej 156-##_other-1039-1-11-20220111.jpg volume 9no. 10 2021 educated hand publishing llc “the science behind the art” volume 9 no.10 2021 anesthesia ejournal online issn 2333-2611 page 19 perioperative management of a patient receiving suboxone® hayden hipps, bsn, rn affiliation: texas christian university grant/financial support: none biographical data: hayden hipps is a registered nurse who is currently enrolled in texas christian university’s nurse anesthesia program. keywords: suboxone, buprenorphine-naloxone, pain management, postoperative pain, perioperative pain. abstract the use of suboxone® in the treatment of opioid addition and/or chronic pain is gaining popularity, and these patients are presenting for surgery more frequently than ever before. the perioperative case management of these patients is complex, especially when they present for elective outpatient surgical procedures.1,3,4,5 this case study evaluated the techniques utilized for analgesia during the preoperative, intraoperative, and postoperative period for a patient undergoing a total laparoscopic hysterectomy. analysis of this case and a review of complementary research articles, revealed that perioperative continuation of suboxone therapy paired with administration of a multimodal analgesia technique, resulted in higher patient satisfaction ratings, a decreased length of hospital stay, and a reduced incidence of chronic pain develop.1,2,3,4,5 these findings are limited to outpatient surgical procedures when postoperative pain is expected to be mild/moderate thus, it is imperative that the anesthesia plan be tailored to the individual patient and surgical procedure after analysis of the risks vs benefits profile. aej volume 5 no. 2 2017 educated hand publishing llc “the science behind the art” volume 5 no. 2 2017 anesthesia ejournal online issn 2333-2611 page 5 how is intraoperative music therapy beneficial to adult patients undergoing general anesthesia? a systematic review d. a. flanagan, msn, crna, dnpc1 athena kerin, ms, crna2 affiliation: 1 columbia university, new york. doctoral candidate at columbia university in new york, new york. graduate of samford university masters of science in nursing with an anesthesia concentration 2suny downstate medical center, new york, ny. associate program director, nurse anesthesia, college of nursing, suny downstate medical center funding/conflict of interest disclosure: there was no financial support for the study. the authors have no conflicts of interest to report. columbia university school of nursing had no role in the design or conduct of the study; the collection, management, analysis, or interpretation of the data; the preparation, review, or approval of the manuscript; or the decision to submit the manuscript for publication. keywords: music therapy, general anesthesia, surgery, intraoperative, headphones, pain introduction the use of music for the treatment of disease processes and ailments can be traced back for millennia. light et al1 found evidence of the use of music for medical treatment as far back as 2500 bc. for centuries, the benefits were observational at best, but music remained as an acceptable adjunct therapy for patients in the health care arena. in english hospitals in the 19th century, musicians were hired to play for sick patients.1 physicians and scientists began to study the effects on physiology and the benefits of music at the turn of the 20th century. it was then that physicians across the world began to record the changes caused by music on vital signs. farr1 pioneered the idea of music in operation suites as early as 1929. in the late 1940s, pickrell and his research team spent 6 years studying the effects of music therapy on preoperative, intraoperative, and postoperative surgical patients.2 their research findings suggest that patients experience decreased fear and apprehension when music is an added element of the surgical experience. pickrell et al2 also noted the use of headphones to be beneficial, not only for delivering the intervention but also as a tool for blocking out nonreassuring noise and conversation inside the surgical arena. theses surgeries were exclusively performed on sedated patients receiving local, spinal, or regional anesthesia. systematic reviews to date have included regional anesthesia (ie, epidural, spinal, and local anesthesia), monitored anesthesia care, and general anesthesia3; however, the present systematic review focused only on those interventions done under general anesthesia. abstract today’s expanding role of technology and the internet-of-things has become an integral aspect of the treatment modalities of health care providers throughout health care systems. with the advent of new devices and online music services, every genre of music is merely a finger touch away for each and every patient. music therapy has been accepted as a beneficial tool used for the treatment of anxiety and pain relief for the conscious patient. research has also been conducted to examine the analgesic benefits of music therapy on the patient undergoing general anesthesia. this systematic review focused on answering the aforementioned question regarding the added effects of music therapy. after thorough examination of the literature, it was concluded that the incorporation of volume-protective headphones and patient-chosen music therapy can be an effective and inexpensive intervention during general anesthesia with statistically significant results for decreased pain, decreased opioid needs, and increased patient satisfaction. aej anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 2 2017 page 6 review of the literature looking at the effects of music during the intraoperative care of the patient under general anesthesia is a subject that has received little scrutiny and study compared with that of patients undergoing regional or spinal anesthesia or sedation. numerous studies have been completed to show the benefit and perceived benefit of music therapy on the anxiety level of patients preoperatively and intraoperatively, but few have specifically addressed the analgesic effects intraoperatively and under general anesthesia.4 anecdotally, in the 1950s music therapy was believed to have a limited effect on the patient undergoing general anesthesia beyond anxiety relief. light et al1 writes of physicians proclaiming that music would have no ability to diminish pain or pain perception. one of the leading pioneers helping to demystify or debunk that concept was composer and researcher linda rodgers emory (professionally: linda rodgers). in an interview, hershenson5 expresses how rodgers challenged this theory by writing music designed for patients to listen to via headphones throughout the perioperative period. patients undergoing general anesthesia or spinal anesthesia showed a decrease in analgesic narcotic intervention compared with patients who did not receive supplemental music therapy during their surgical course.5 at least 2 studies have documented the stress responses of sound therapy intraoperatively on patients undergoing general anesthesia. migneault et al6 conducted a pilot study of 30 patients that examined the stress response of female patients intraoperatively while listening to their choice of music during the administration of general anesthesia. the patients chose 1 of 4 genres of music in the preoperative department and then had intraoperative blood drawn from an arterial line that had been placed during the induction of anesthesia. blood samples, collected at timed intervals, measured comparable blood levels of epinephrine, norepinephrine, cortisol, and adrenocorticotropic hormone between a music therapy group and a control group. the second study utilized hemispheric-synchronization (hemisync; monroe products, lovingston, va) therapy. hemi-sync therapy is the process of listening to sound waves through headphones that theoretically cause the brain to create a third sound, the binaural beat, which synchronizes both sides of the brain and aids in relaxation, pain response, and sleep patterns.7 the implementation of intraoperative hemisphericsynchronization therapy provided evidence for a reduction in hormonal stress response for patients during surgery.8 these studies serve as a springboard into the potential benefits of the adjunct, noninvasive, and cost-effective treatment modality of intraoperative music therapy for patients undergoing general anesthesia. given the side effects associated with opioids, including nausea, prolonged time to wake up, and decreased respiratory effort, it would be beneficial to add a noninvasive, low-cost, patientempowering intervention that would significantly increase analgesia while simultaneously decreasing side effects associated with narcotic administration. the aim of this systematic review was to determine whether intraoperative music therapy for adult patients is an effective modality to be used in the practice of general anesthesia. the 2 variables used to measure outcomes were the patient pain score on a visual analogue scale (vas) and the amount or quantity of pain medicine administered via anesthesia staff or postoperative nurse (as morphine-equivalent dosing). search strategy method a literature search of articles published from january 1980 to january 2016 was performed on the ovid medline database (ovid, new york, ny), the cumulative index to nursing and allied health literature (cinahl; ebsco, ipswich, ma), pubmed (national library of medicine, bethesda, md), embase (elsevier, amsterdam, netherlands), and the cochrane library (the cochrane collaboration, london, united kingdom). articles reporting findings from studies on human subjects and written in english were considered. the following search terms were used: music, surgery, therapy, anesthesia, anaesthesia, pain, preoperative, intraoperative, and postoperative. the search was executed with words individually and with combined searches including music/surgery, music/therapy, and music/ surgery/therapy to gather the widest range of research articles. exclusion criteria for articles included patients aged less than 18 years; studies that used regional anesthesia, local anesthesia, or monitored anesthesia care; and any nonrandomized clinical trials as well as studies that only measured anxiety scores as an outcome variable. inclusion criteria included randomized clinical trials (rcts) written in english and those whose outcome measures were pain score, narcotic amount received, and/or patient satisfaction. minimally, studies needed to explicitly include the music therapy intervention during the intraoperative period. following the primary search, a secondary search using scopus (elsevier, amsterdam, netherlands), the virtual health library (world health organization, geneva, switzerland), and hand searching was conducted. duplicate articles were removed while studies including rcts and performed in adult patients were included in the second screening. the remaining articles were analyzed and those measuring only anxiety as an outcome measure were discarded. music interventions were limited to those carried out both preoperatively and intraoperatively, intraoperatively alone, intraoperatively and postoperatively together, as well as those rcts that performed the music interventions throughout the surgical experience. quality appraisal a quality appraisal of each study was achieved by using the pedro scale to rate articles. the pedro scale was established to aid readers in determining the external and internal validity of rcts, specifically those trials stored on the pedro database. the scale does not measure the validity of conclusions but does take into account whether an rct has sufficient statistical data to make interpretations. the pedro scale questions, which are depicted in figure 1, are answered on a yes or no basis. each yes is rewarded 1 point for a total potential score of 10. rcts that score >6 to 10 are regarded as moderate to high-quality rcts with respect to methodology. verhagen and partners at the department of epidemiology, university of maastricht, derived these criteria from the delphi list. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 2 2017 page 7 figure 1. the pedro scale for determining the external and internal validity of randomized clinical trials. source: centre for evidence-based physiotherapy (https://www.pedro.org.au). the pedro scale was used to assign each article a total quality score for methodology and was subsequently analyzed for outcome measures. quality appraisals were completed individually by both the author and the co-author and then compared and discussed to come to a consensus of ratings. results the primary search yielded 103 articles, whereas a secondary search using scopus, the virtual health library, and hand searching yielded an additional 438 articles. after accounting for duplicate articles, a total of 504 articles were screened for eligibility for the review. of the 504 screened, 426 were excluded, leaving only rcts for adult patients. the remaining 78 articles were further analyzed and articles that did not meet the inclusion criteria, such as those measuring only anxiety as an outcome measure, were discarded. as outlined in figure 2 on the prisma flowchart,9 8 rcts met the inclusion criteria following this literature search.10-17 all of the 8 studies assessed were published between 1995 and 2013. figure 2. prisma study flowchart. the 8 rcts differed in patient characteristics and type of surgery. the musical intervention varied by type as well as the timing of the intervention, which included preoperative and postoperative music therapy in addition to the mandated intraoperative period. baseline characteristics the 8 rcts appraised included a total of 610 patients. the range of sample sizes for each study was from a study13 of 10 to the largest study16 of 151. the mean age of the patients ranged from 35 years in one study14 to 61 years in the study11 with the most advanced age. three10,14,15 of the studies included only female participants and the remaining 5 rcts11-13,16,17 included both men and women as participants. the patients in the rcts underwent a number of elective surgeries. the variety of surgeries included gynecology, cardiac, abdominal, breast, and orthopedic surgeries. one study of gynecological surgical patients had a broader inclusion criterion for the types of surgeries performed.14 the other 7 studies had specific criteria for the type of patients within the study so that all participants were undergoing the same surgical procedure.10-13,15-17 intervention the vast majority of rcts included the musical intervention both intraoperatively and postoperatively (n=7). of those 7 studies, 3 also included the musical intervention preoperatively.10,12,14 only one study placed the musical intervention solely during the intraoperative period.15 the type of music varied among the studies. two of the studies gave participants a choice of the genre of music.10,13 the choices of genre included classical, easy listening, new age, and inspirational in one study10 versus classical, country, and instrumental in the other study.13 the other 6 studies supplied patients with no consistent musical intervention.11,12,14-17 despite the differing musical intervention, researchers in each study chose music that had been deemed soothing and calming, from musicure (gefion records, copenhagen, denmark)12 to sea waves and calm sounds to dreamflight ii by herb ernst.11 records identified through database searching pubmed, embase, cinahl, cochrane library (n =103) additional record identified through other sources: scopus virtual health library and hand searching (n=438) records after duplicates removed (n = 504) records screened (n = 504) records excluded (n = 426) full-text articles assessed for eligibility (n = 78) full-text articles excluded, with reasons (n= 70) 10 wrong anesthetic (regional) 21 wrong comparator (anxiety/ time) 8 wrong intervention (hemi-sync/ dance/hypnosis) 2 wrong population 29 wrong study design studies included in qualitative synthesis (n = 8) ide nti fic ati on s sc re en ing el igi bil ity inc lud ed figure 2 from: moher d, liberati a, tetzlaff j, altman dg, the prisma group (2009). preferred reporting items for systematic reviews and metaanalyses: the prisma statement. plos med 6(6): e1000097. doi:10.1371/journal.pmed1000097 for more information, visit w ww.prisma-statement.org. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 2 2017 page 8 the majority of studies used headphones for the participants (n=7). one of the studies used a musical pillow for the participants.12 the volume of music differed among participants from study to study. three studies set the audio level at the same level for each participant.15-17 two10,13 studies allowed the patients to set their preferred volume level with only one10 of these 8 rcts setting a maximum decibel level (70 db). the study characteristics are summarized in table 1. table 1. characteristics of the 8 studies included in the systematic reviewa study authors, year, setting & study type quality score n, surgery type & mean patient age (y) tool used to assess outcome intervention period groups binns-turner et al10 2011, usa quasi-experimental study 10 • n = 30 f (convenience sample) • mastectomy for breast cancer • mean age = 57 vas for pain • preop • intraop • postop 1. music therapy 2. control blankfield et al11 1995, usa single-blind trial 9 • n = 95 (30 f, 65 m) • coronary artery bypass • mean age = 61 amount of narcotic administered postop • intraop • postop: 30 min twice daily 1. suggestion therapy 2. music therapy 3. control graversen & sommer12 2013, denmark rct 9 • n = 75 (55 f, 20 m) • laparoscopic cholecystectomy • mean age = 47 vas for pain and amount of narcotic administered postop • preop • intraop • postop 1. music therapyb 2. control heiser et al13 1997, usa repeated-measures experimental design 8 • n = 10 (5 f, 5 m) • lumbar microdiscectomy • mean age = 39 vas for pain • intraop • postop 1. music therapy 2. control laurion & fetzer14 2003, usa experimental pilot study 8 n = 84 f gynecological laparoscopic surgery mean age = 35 vas for pain • preop: at least 2 times a day • intraop • postop 1. guided imagery 2. music therapy 3. control nilsson et al15 2001, sweden double-blind rct 10 • n = 89 f • hysterectomy • mean age = 51 vas for pain • intraop 1. music therapy 2. combined: music and therapeutic suggestions 3. control nilsson et al16 2003, sweden rct 10 • n = 151 (44 f, 107 m) • inguinal hernia repair or varicose veins • mean age = 54 vas for pain • intraop • postop 1. intraop music therapy 2. postop music therapy 3. control nilsson et al17 2005, sweden rct 10 • n = 75 (3 f, 72 m) • open hernia • mean age = 56 vas for pain • intraop • postop 1. intraop 2. postop 3. control aabbreviations: f, female; intraop, intraoperative; m, male; postop, postoperative; rct, randomized clinical trial; vas, visual analogue scale. btherapy chosen per day and not per patient. quality four of the 8 rcts were evaluated to have the maximum quality methodology score of 10 as measured by the pedro scale.10,15-17 the range of scores was from 8 to 10 with a mean score of 9. two11,12 studies received a 9 and the two13,14 remaining studies received an 8. the majority of the included studies (n=7) utilized a valid and reliable measurement for the outcome measures. these 7 studies all used a vas in order to measure the level of pain of each participant.10,12-17 the one11 remaining study used continuous measurements in order to measure the overall quantity of narcotics administered for comparison. blinding six of the studies were single-blind studies.10,11,13,14,16,17 these studies placed headphones on all participants. researchers would then provide the intervention group with the music therapy cd or tape and the control group listened to a blank tape or cd. one study was double-blinded for the patients and the researchers, as headphones were placed on the participants intraoperatively.15 neither the researcher nor the participant knew to which group the participant was ascribed. one study had no blinding as the therapy was provided aloud without headphones compared with the control group without any music.12 three of the 8 studies had true computer-generated randomization to groups for participants.15-17 another 3 of the rcts did not offer specific terms for randomization.11,13,14 these studies did mention that patients were randomly assigned to groups. the remaining 2 studies drew numbers from resalable bags.10,12 one study10 drew numbers for group determination, whereas the other study12 drew numbers for that day’s intervention (music therapy day vs control or non-music-therapy day). the quality appraisal results are graphed in figure 3. figure 3. randomized clinical trial quality appraisal according to pedro score. outcome measures all of the 8 articles reviewed had the common outcome measure of pain. pain was measured in 2 different ways, either with a vas or by the amount of analgesic administered. seven of the rcts used a vas to measure the pain of the participants at various stages during the study.10,12-17 one study showed a significantly greater decrease in pain levels for the intervention group and a lower pain score postoperatively.10 in another study, half of patients who listened to the music stated that it was helpful and these same satisfied participants also received fewer analgesics than did the control group.11 in one article, the participants of the music group had less pain on postoperative day 7.12 when comparing analgesic use, 6 articles reviewed used morphine equivalents as the outcome measure of pain.11-13,15-17 two studies showed no difference in the amount of morphine equivalents.11,12 it is important to note that general anesthesia can induce physiological fluctuations that require immediate and active intervention. opioid analgesics, such as morphine or hydromorphone hydrochloride (dilaudid, purdue pharma), are administered when pain is considered a differential diagnosis. studies are lacking regarding treatment thresholds in managing the patient’s hemodynamic status intraoperatively when treating pain. however, 4 studies showed that the music therapy group required less analgesic medicine after discharge.13,15-17 table 2 highlights the data collection measures and results of each study. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 2 2017 page 9 table 2. study interventions, results, and limitations for the 8 studies included in the systematic reviewa study data collection intervention results limitations binns-turner et al10 2011, usa preop and discharge • music selection: participants chose between classical, easy listening, inspirational, or new age • headphones: yes • limited volume 70 db • double-blind • women in intervention group reported significantly greater decrease in pain levels • pain significantly lowered and improved postoperatively in intervention group 1. type ii error (need larger sample size) 2. hawthorne effect: patients knew pain was being measured blankfield et al11 1995, usa discharge and 1 mo after discharge • music selection: patient had no choice; dreamflight ii by herb ernest • headphones: yes • no mention of volume • double-blind • no significant difference in amount of morphine equivalents 1. suggestion group had background music (music vs. suggestion) 2. patients only listened for a short period 3. no preop listening graversen & sommer12 2013, denmark 1 h postop, 3 h postop, 1 d postop, and 7 d postop • music selection: patient had no choice; musicure • headphones: no (musical pillow) • no mention of volume • single-blind • no significant difference in amount of morphine in recovery • no difference at primary endpoint at 3 h • music group reported less pain at day 7 1. minimally invasive surgery not painful enough to show difference at end of surgery 2. music could be heard from small distance 3. participants could not shut out external sounds of unit 4. study design did not allow blinding 5. patient personal music selection heiser et al13 1997, usa 1 h in pacu and 24 h after surgery before discharge • music selection: participant chose between country, instrumental, classical • headphones: yes • patient chose preferred volume level • single-blind • music group required less analgesic medications after discharge 1. type ii error (need larger sample size) 2. no preop/baseline for pain levels laurion & fetzer14 2003, usa experimental pilot study on arrival to pacu, 1 h, and discharge • music selection: participant had no choice (piano); naparstek “health journeys for people undergoing surgery” • headphones: yes • no mention of volume • double-blind • control group had higher pain score at discharge to home 1. type ii error (need larger sample size) 2. patient personal music selection 3. ethnically homogeneous sample (all white) nilsson et al15 2001, sweden every hour for 1st 24 h, then every 3 h until no pain • music selection: participants had no choice; sea waves and calm sounds • headphones: yes • same audio levels for each patient • double-blind • day of surgery: music/therapeutic suggestions group required less analgesic medication than control group • first day after surgery, music group had more effective analgesia with less pain and less pain medication administered • although not statistically significant, total dose of pain meds was lower in music group 1. music better than soothing message (no difference added with combined verbal message) 2. patient personal music selection nilsson et al16 2003, sweden every 0.5 h for 2 h postop, every 1 h for 1st 24 h, then every 3 h until no pain • music selection: participants had no choice; instrumental • headphones: yes • same audio levels for each patient • double-blind • intraop group and postop group both had significantly lower pain scores at 1 h and 2 h postop • postop music group required less morphine at 1 h • no difference in music intraop vs postop (but beneficial) 1. patient personal music selection nilsson et al17 2005, sweden data collection: 30 min before anesthesia, 1 h after in pacu • music selection: participants had no choice; soft new age synthesizer • headphones: yes • same audio levels for each patient • double-blind • both groups had lower pain scores than control group at 1 h in pacu • postop group: less pain and required less morphine after 1 h in pacu • total morphine requirement was significantly lower than control group (intraop morphine requirement was lower as well but not significantly so) • increased pain relief and decreased morphine consumption 1. subcutaneous local anesthesia infiltration at end of surgery 2. patient personal music selection aabbreviations: intraop, intraoperative; pacu, post-anesthesia care unit; postop, postoperative; preop, preoperative. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 2 2017 page 10 almost 90% (7 of 8) of the articles reviewed showed a lower pain score for the music intervention group after arrival in the post-anesthesia care unit (pacu) or during the subsequent recovery period.10,12-17 one study measured both a preoperative pain score and a postoperative pain score.10 the participants in the music therapy group experienced a 41.4% smaller increase in pain compared with the pain levels of the women in the control group. six studies compared the total quantity of opioids needed to achieve pain relief between the control group and the intervention group. four of the 6 studies (67%) showed a decrease in morphine-equivalent dosing for patients in the music intervention groups.13,15-17 the other 2 studies showed no difference in the amount of dosing between control and intervention groups.11,12 even when the dose of narcotics did not change, the pain perception was lowered as evident in the lowered pain scores recorded. in the 3 studies that used questionnaires to measure patient satisfaction with the surgical experience, all 3 studies (100%) showed a higher patient satisfaction score for the music intervention groups than for the control groups.11,13,16 discussion the results of this systematic review show that intraoperative music therapy for the patient receiving general anesthesia can reduce pain during the perioperative period as well as increase patient satisfaction with the surgical experience. by far, the most important finding among the 8 studies is that 5 studies resulted in significantly decreased pain scores in the music therapy groups who received intraoperative interventions.10,14-17 as an inexpensive intervention, with controllable volume-limiting damage perimeters, ie, the ability to increase the volume up or down to acceptable levels, intraoperative music has been shown to be beneficial for pain control and the overall surgical experience of patients. this review shows the importance of music delivery as well as music selection on the outcomes of a music intervention for patients undergoing general anesthesia. two studies allowed the participants in the intervention group to choose their type of music.10,13 the patients in these studies showed decreased pain and expressed positive surgical satisfaction. patient music selection did not have a profound effect on the success of the music intervention nor a direct correlation to increased patient satisfaction, but it did allow control and autonomy in an otherwise unfamiliar, outsider-controlled environment. allowing patients to choose their music empowers them with a sense of autonomy and control previously lost when entering the surgical suite. patient safety, both shortand long-term consequences, was regarded in the application of the music therapy. the occupational safety and health administration (osha) reports that sustained sounds above 70 db can cause permanent hearing damage in humans.18 with operating room sounds easily reaching levels greater than 70 db, various hazards associated with unsafe decibel levels are heard during surgery by staff and even worse, the anesthetized patient, who cannot attenuate audible sounds due to the muscle-relaxing effect of the anesthetic agents or drugs.19 headphones are the best means of blocking out ambient operating room sound while also supplying the patient with a sustained safe decibel volume of music therapy. the majority of the studies, 5, either used devices with limits on volume output or allowed the participants to choose a suitable volume for their comfort level.10,13,15-17 the device that supplies the music should have a maximum volume <68 db to prevent the risk of permanent hearing damage. with the national institute for occupational safety and health having declared that sound exposure to 90 db for greater than 8 hours has the potential to cause irreversible hearing damage, osha18 concludes that a 25% decrease in volume ensures a healthy listening experience for the patient. any music therapy implemented would need to ensure no harm to the patient and providing volume-limiting headphones resolves this issue. given the results of this systematic review showing the benefits on patient pain scores, decreased narcotic use, and increased patient satisfaction of intraoperative music therapy for the patient under general anesthesia, figure 4 outlines 5 major components to ensure the success of an intraoperative music therapy intervention. figure 4. five components of a successful intraoperative music therapy intervention. at the forefront of this discussion on music therapy and patient selection is an area for improved medical care. as a complementary method of improving pain control, patient-chosen music therapy offers the advantage of patient empowerment and patient-centered care. in the new landscape of medical access and knowledge, patients expect autonomy and decision-making authority from medicine as a service industry. patient empowerment is a leading care model used throughout the health system and offers numerous benefits, including but not limited to patient satisfaction and patient accountability.20 giving the patient the option to choose both empowers and increases patient satisfaction scores, and music therapy with its limited cost and additional analgesic benefits offers an inexpensive patientcentered solution for patient care, comfort, and pleasure. future research as zusman21 details, given the reimbursement change under the patient protection and affordable care act, value-based patient care, measured by patient satisfaction scores, has taken a larger role in the management of care within american health care systems. the hospital consumer assessment of healthcare providers and systems (hcahps) survey is the national standard by which hospitals and patient experiences are measured and has become one of the elements that determine how much reimbursement facilities receive from the centers for medicare and medicaid services (cms).22 as reimbursement changes, the effectiveness of intraoperative music therapy can prove very beneficial for increased reimbursement numbers for facilities throughout the health care system. with the decreased checklist for music therapy in general anesthesia • headphones (as procedure permits) • adjustable volume not to exceed <68 db • patient chosen genre • application upon or entry (prior to induction) • discontinue >1 hour after pacu admission anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 2 2017 page 11 pain scores and added patient satisfaction, it will be important to dissect more details of the music therapy intervention. these 8 studies included various types of music genres and selections as well as variously timed implementations. as more research is carried out, more details should emerge adding more validity to the specific genre of music that should be most beneficial to the patient. however, as the battle continues between patient-centered care and patient empowerment, surveys should be administered regarding the preferences of the patient themselves. if patients were actually given the choice of genre supplied during music therapy, would more satisfaction be obtained from the choice of “medically appropriate compositions” or a patient’s individual preference? does the evidence outweigh the broad spectrum of music in a way that limiting options to “medically appropriate compositions” would suffice for patient satisfaction and adequate analgesic benefit? these are questions that need to be explored with future research. the delivery and supply of safe headphones should be investigated further as well. many hospitals have protocols in place that require materials management to inspect every piece of electrical equipment brought forth by a visitor for use within the hospital setting. because of the effectiveness of intraoperative music therapy on the patient receiving general anesthesia, systems should be designed and studied to determine best practices for safe, uncontaminated headphones to be used in the operating room. these options vary immensely from patients supplying their own headphones to the facility providing a pair of sealed and clean headphones to each patient upon arrival in the operating room. these are just a few of the logistical concerns that must be further investigated to move forward with the implementation of music therapy across all facility platforms. limitations this systematic review included only articles published in english. this could have introduced a language bias for the assessed outcomes. publication bias is also a risk because not all rcts are published owing to a lack of significant conclusions.23 this systematic review examined 3 divisions of the surgical process with a focus on the intraoperative period. the review is limited in its conclusion of which time period of the music therapy intervention provided the best success. there were no direct comparisons between the 5 possible combinations of when the music therapy could be applied in relation to the intraoperative period (ie, preoperative vs postoperative or intraoperative exclusively or any combination of the 3). another limitation was that the 8 reviewed studies were not evaluated on the basis of sample size nor respective sample size calculations. at least 2 of the 8 studies included sample sizes of 30 or fewer owing to convenience sampling and the subtraction of excluded participants and data. decreased sample sizes have the potential of creating a type 2 error as well as drawing conclusions that are nongeneralizable. nilsson et al3 used the explanation and inclusion of sample size calculations as an aspect of the quality appraisal of research assessed in a past systematic review. conclusion as clinicians search for ways to improve outcomes while satisfying the needs, wants, and expectations of their consumers, music therapy is one of the simplest and least expensive avenues for success that both benefits the patient by decreasing pain while also potentially increasing revenue for clinicians. in this setting, music therapy is an underused technique that has demonstrated numerous patient benefits as well as positive effects on the patient experience and that could lead to increased government reimbursement. hospitals and clinicians wishing to improve the surgical experience for consumers, while being innovative leaders in the modalities of pain management, should consider adopting intraoperative music therapy as an option for surgery. summary of key points music therapy with headphones under general anesthesia is effective in reducing pain, reducing narcotic needs, and increasing patient satisfaction scores. allowing patients to choose the genre of music increases autonomy and is a way to empower patients in an otherwise irrepressible situation. checklist for music therapy in general anesthesia checklist for music therapy in general anesthesia • headphones (as procedure permits) • adjustable volume not to exceed <68 db • patient chosen genre • application upon or entry (prior to induction) • discontinue >1 hour after pacu admission acknowledgment the authors acknowledge kristine kulage, ma, mph, columbia university school of nursing, for her review of this manuscript and significant contribution to the organization of the review. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 2 2017 page 12 references 1. light ga, love dm, benson d, morch et. music in surgery. curr res anest anal. 1954;258-264. 2. pickrell kl, metzger jt, wilde nj, broadbent tr, edwards ef. the use and therapeutic value of music in the hospital and operating room. plast reconstr surg. 1950;6(2):142-152. https://doi.org/10.1097/00006534-195008000-00005. 3. nilsson u. the anxietyand pain-reducing effects of music interventions: a systematic review. aorn j. 2008;87(4):780-807. https://doi.org/10.1016/j.aorn.2007.09.013. 4. wakim j, smith s, guinn c. the efficacy of music therapy. j perianesth nurs. 2010;25(4):226-232. https://doi.org/10.1016/j. jopan.2010.05.009. 5. hershenson r. musical family’s contribution to society. the new york times. http://www.nytimes.com/1994/04/10/nyregion/ musical-family-s-contributions-to-society.html. updated april 10, 1994. accessed march 15, 2016. 6. migneault b, girard f, albert c, et al. the effect of music on the neurohormonal stress response to surgery under general anesthesia. anesth analg. 2004;98:527-532. https://doi.org/10.1213/01.ane.0000096182.70239.23. 7. hemi-sync. http://www.hemi-sync.com. accessed april 9, 2016. 8. kliempt p, ruta d, ogston s, landeck a, martay k. hemispheric-synchronization during anesthesia: a double-blind randomised trial using audiotapes for intra-operative nociception control. anaesthesia. 1999;54(8):769-773. https://doi. org/10.1046/j.1365-2044.1999.00958.x. 9. moher d, liberati a, tetzlaff j, altman dg. prisma group. preferred reporting items for systematic reviews and metaanalyses: the prisma statement. plos med. 2009;6(7):e1000097. https://doi.org/10.1371/journal.pmed.1000097. 10. binns-turner p, wilson l, pryor e, boyd g, prickett c. perioperative music and its effects on anxiety, hemodynamics, and pain in women undergoing mastectomy. aana j. 2011;79(4):s21-s27. 11. blankfield rp, zyzanski sj, flocke sa, alemagno s, scheurman k. taped therapeutic suggestions and taped music as adjuncts in the care of coronary-artery-bypass patients. am j clin hypn. 1995;37(3):32-42. https://doi.org/10.1080/00029157.1995.104 03137. 12. graversen m, sommer t. perioperative music may reduce pain and fatigue in patients undergoing laparoscopic cholecystectomy. acta anaesthesiol scand. 2013;57(8):1010-1016. https://doi.org/10.1111/aas.12100. 13. heiser r, chiles k, fudge m, gray s. the use of music during the immediate postoperative period. aorn j. 1997;65(4):777785. https://doi.org/10.1016/s0001-2092(06)62999-2. 14. laurion s, fetzer sj. the effect of two nursing interventions on the postoperative outcomes of gynecologic laparoscopic patients. j perianesth nurs. 2003;18(4):254-261. https://doi.org/10.1016/s1089-9472(03)00131-x. 15. nilsson u, rawal n, uneståhl le, zetterberg c, unosson m. improved recovery after music and therapeutic suggestions during general anaesthesia: a double-blind randomised controlled trial. acta anaesthesiol scand. 2001;45(7):812-817. https:// doi.org/10.1034/j.1399-6576.2001.045007812.x. 16. nilsson u, rawal n, unosson m. a comparison of intra-operative or postoperative exposure to music—a controlled trial of the effects on postoperative pain. anaesthesia. 2003;58(7):699-703. https://doi.org/10.1046/j.1365-2044.2003.03189_4.x. 17. nilsson u, unosson m, rawal n. stress reduction and analgesia in patients exposed to calming music postoperatively: a randomized controlled trial. eur j anaesthesiol. 2005;22(2):96-102. https://doi.org/10.1017/s0265021505000189. 18. occupational health and safety administration. occupational noise exposure. https://www.osha.gov/sltc/ noisehearingconservation/#loud. accessed may 13, 2016. 19. schambo l, umadhay t, pedoto a. music in the operating room: is it a safety hazard? aana j. 2015;83(1):43-48. 20. grol r. improving the quality of medical care: building bridges among professional pride, payer profit and patient satisfaction. jama. 2001;286(20):2578-2585. https://doi.org/10.1001/jama.286.20.2578. accessed march 13, 2016. 21. zusman ee. hcahps replaces press ganey survey as quality measure for patient hospital experience. neurosurgery. 2012;71(2):n21-n24. https://doi.org/10.1227/01.neu.0000417536.07871.ed. 22. center for medicare and medicaid services. hcahps: patients’ perspectives of care survey. https://www.cms.gov/medicare/ quality-initiatives-patient-assessment-instruments/hospitalqualityinits/hospitalhcahps.html. updated september 25, 2014. accessed may 13, 2016. 23. vader jp. randomised controlled trials: a user’s guide. bmj. 1998;317:1258. https://doi.org/10.1136/bmj.317.7167.1258. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 2 2017 page 13 148-##_other-1030-1-11-20220111.jpg volume 9no. 6 2021 educated hand publishing llc “the science behind the art” volume 9 no.6 2021 anesthesia ejournal online issn 2333-2611 page 11 anesthetic management of a patient with von willebrand disease elaine juch, bsn, rn, affiliation: texas christian university grant/financial support: none biographical data: elaine juch is a senior rrna at texas christian university in fort worth. she would like to acknowledge the work of courtney mcneill, crna, preceptor for guidance during this unique case. keywords: von willebrand disease, type i, bleeding, desmopressin, transesophageal echocardiogram abstract this case report describes an anesthesia-related issue encountered during a watchman device placement and transesophageal echocardiogram (tee) where profuse perioperative esophageal bleeding ensued in a patient with von willebrand disease (vwd) type 1. prolonged bleeding of mucosal surfaces is common in patients with type i vwd and should be considered when attempting any procedure involving bruising or trauma to the oropharynx such as tee or esophagogastroduodenoscopy (egd).1 the patient had also been taking aspirin, which can precipitate bleeding that may not have occurred otherwise. patients with vwd often need a combination of multiple therapies to treat uncontrolled bleeding. anesthesia providers should be aware of the risk of bleeding, premedication, and which medications and clotting factors to give next should desmopressin be insufficient. aej 153-##_other-1032-1-11-20220111.jpg volume 9no. 7 2021 educated hand publishing llc “the science behind the art” volume 9 no.7 2021 anesthesia ejournal online issn 2333-2611 page 13 decreased pulse oximetry readings in asymptomatic patient with hemoglobin grifton anne marie serrano1, christian r serrano2, and monica jenschke3 affiliation: 1 anne marie serrano, bsn, rn, texas christian university, school of nurse anesthesia, fort worth, tx 2 christian r serrano, ms, bs, department of biology, university of texas at san antonio, san antonio, tx 3 monica jenschke, phd, crna, texas christian university, school of nurse anesthesia, fort worth, tx grant/financial support: none biographical data: elaine juch is a senior rrna at texas christian university in fort worth. she would like to acknowledge the work of courtney mcneill, crna, preceptor for guidance during this unique case. keywords: hemoglobin grifton, hemoglobinopathies, pulse oximetry abstract hemoglobin grifton presents as a decreased oxygen saturation as measured by pulse oximetry (spo2) reading despite a normal arterial oxygen saturation (sao2) in an asymptomatic patient. hemoglobin grifton is caused by a mutation on an alpha chain of hemoglobin at codon 87, which affects the absorption wavelength of its oxyhemoglobin. a standard pulse oximeter is designed to measure the absorption of light at specific wavelengths and perceives the hemoglobin grifton oxyhemoglobin as a deoxyhemoglobin. in a patient with a known variant hemoglobin, ordering additional diagnostic or therapeutic testing can increase stress for a patient requiring routine medical interventions or emergencies. careful evaluation of each individual case is warranted prior to proceeding with an anesthetic. previous case studies reported variant hemoglobinopathies, specifically on the alpha chain, that produce a false low spo2 reading. in these case studies, the arterial blood gas resulted in normal oxygen saturation. another case study reported that the issue with hemoglobin grifton was the oxyhemoglobin grifton absorbed light at approximately 740 nm. the light absorption on normal oxyhemoglobin is at a wavelength of 940 nm. because of this, the hemoglobin grifton is detected by the pulse oximeter monitor as deoxyhemoglobin. standard transcutaneous pulse oximeters do not consider the different absorbance spectra of variant hemoglobinopathies where the oxyhemoglobins may be absorbed at lower spectrums. in all the literature reviewed, patients went through a myriad of unnecessary diagnostic tests to figure out the cause of the hypoxia. some patients were even prescribed treatment based on this false hypoxia. this results in unnecessary additional expenses for treatment and can also cause stress for patients. the patient in this case study presented with a baseline spo2 of 84% with a known diagnosis of hemoglobin grifton. the surgeon was unable to do this procedure in the clinic due to the child’s agitated behavior and general anesthesia was required. the decision was made to forgo invasive testing due to her known condition and the unnecessary stress it would add to the patient. aej 144-##_other-1020-1-11-20211222.jpg volume 9no. 2 2021 educated hand publishing llc “the science behind the art” volume 9 no.2 2021 anesthesia ejournal online issn 2333-2611 page 3 spinal anesthesia for total joint replacement trey t. overla, bsn, rn, rrna affiliation: texas christian university grant/financial support: none biographical data: trey t. overla is a registered nurse pursuing his dnp in nurse anesthesia at texas christian university in fort worth, texas. keywords: spinal anesthesia, general anesthesia, anesthesia, total joint arthroplasty, total joint replacement, total hip replacement, total knee replacement abstract total joint arthroplasty is one of the most performed surgical procedures in the developed world with millions of total hip and total knee replacements taking place each year.1 it has long been debated whether general anesthesia or neuraxial anesthesia is the best choice for lower limb total joint arthroplasty. the purpose of this scientific poster is to explore and discuss the potential benefits of using spinal anesthesia rather than general anesthesia for total knee arthroplasty or total hip arthroplasty. a database search utilizing embase, medline complete, and pubmed was completed to obtain information for the poster. after data and resources were reviewed, several benefits were discovered related to the use of spinal anesthesia for total joint arthroplasty. benefits included lower 30-day mortality rates, decreased odds for allcause mortality and fewer complications in most cases, lower 90-day complication rate, decreased postoperative nausea and vomiting, and decreased medical costs.1-6 according to the literature, a systematic review and meta-analysis, and a multinational expert group neuraxial anesthesia is the preferred anesthetic technique due to its reduction of most (but not all) complications.1 spinal anesthesia is the preferred method of anesthesia for total knee and total hip arthroplasty given the positive associated postoperative outcome benefits.1 aej texas christian university “the science behind the art” volume 10 no.3 2022 anesthesia ejournal online issn 2333-2611 page 5 effect of dexmedetomidine on incidence of emergence delirium in adult nasal surgery christopher steinkampf, bsn, rn affiliation: texas christian university grant/financial support: none keywords: anesthesia, dexmedetomidine, emergence, nasal surgery abstract emergence delirium (ed) is an acute phenomenon that develops in the early phase of recovery from general anesthesia, and characterized by confusion, disorientation, and possible violent behavior, and is a common occurrence particularly with nasal surgery. dexmedetomidine is a highly selective alpha-2 adrenergic agonist that results in anxiolysis, sedation, analgesia, and sympatholysis without depressing ventilation. 392 participants across five studies revealed a lower incidence of ed in dexmedetomidine groups than control groups (21% vs 50%). mean arterial pressure (map) and heart rate (hr) among dexmedetomidine groups exhibited less variability during emergence without hypotension, which indicates a more stable hemodynamic profile. analgesic and antiemetic requirements in the post-anesthesia care unit (pacu) were decreased in dexmedetomidine groups, however these results were not statistically significant. intraoperative dexmedetomidine significantly decreases the incidence of ed. secondary effects, like hemodynamic stability and analgesia, were observed, but these qualities need to be further studied before they can be generalized. aej volume 10no. 3 2022 about the author: christopher steinkampf is a registered intensive care unit nurse, currently enrolled in texas christian university nurse anesthesia program. texas christian university “the science behind the art” volume 10 no.3 2022 anesthesia ejournal online issn 2333-2611 page 6 powerpoint template ©2009 texas christian university, center for instructional services. for educational use only. content is the property of the presenter and their resources. introduction • emergence delirium (ed) an acute phenomenon that develops in the early phase of recovery from anesthesia, and characterized by confusion, disorientation, & possible violent behavior • may lead to serious complications: self-extubation, aspiration, hypoxia, increased pain, or bleeding • risk factors: male gender, younger age, patient personality, preoperative anxiety, rapid awakening, postoperative pain, type of surgical procedures, inhalational anesthetics, and presence of tracheal tube2-6 • higher incidence with nasal surgery due to postoperative nasal packing that can simulate the feeling of suffocation2 • dexmedetomidine – alpha-2 adrenergic agonist that binds at presynaptic and postsynaptic site (figure 3), which causes decrease in norepinephrine levels1 • dexmedetomidine produces sedative, analgesic, and sympatholytic effects without respiratory depression1 • picot: in adult patients undergoing nasal surgery, does intraoperative dexmedetomidine compared to a placebo decrease the incidence of ed, as assessed by the riker sedation-agitation scale (table 1), immediately after extubation? review of literature • five rcts assessed how intraoperative dexmedetomidine effected the recovery profile on adults after general anesthesia; primary measurement – ed • total of 396 asa i or ii patients aged between 18 to 65 years scheduled for elective nasal surgery; 196 in dexmedetomidine group (group d), 196 in control group (group c) • each rct reported a significant decrease in the incidence of ed in the dexmedetomidine groups • collectively, of the 196 group d patients, 42 (21%) experienced ed and of the 196 group c patients, 98 (50%)2-6 (p < 0.05) • the sympatholytic and analgesic properties of dexmedetomidine provided a more stable hemodynamic profile during emergence and decreased analgesic requirements, which may have also decreased antiemetic requirements • heart rate and mean arterial pressure were consistently more stable during emergence in group d compared to group c2-6 • analgesic and antiemetic requirements in the pacu were decreased in group d compared to group c2-6 • dexmedetomidine’s effect on pacu length of stay was inconsistent across these studies, but there was not a clinically significant difference between group d and group c2-6 • gaps in knowledge: long-term effects of dexmedetomidine beyond pacu and 24h, bolus vs. infusion vs. combination, applicability to asa > ii, applicability to other surgeries effect of dexmedetomidine on incidence of emergence delirium in adult nasal surgery christopher steinkampf bsn, rn, texas christian university evidence search strategy • databases: pubmed and embase • keywords: anesthesia, dexmedetomidine, emergence, nasal surgery • further limits: publication date 2011 to 2021, “english only”, and “human only” • 29 studies were identified • evidence was refined by focusing on rct, systematic reviews, and meta-analyses • five rcts were chosen based on their research procedures and primary outcomes references 1. katzung, bg. basic & clinical pharmacology. 14th ed. new york: mcgraw hill-education; 2017. 2. garg a, kamal m, mohammed s, singariya g, chouhan ds, biyani g. efficacy of dexmedetomidine for prevention of emergence agitation in patients posted for nasal surgery under desflurane anaesthesia: a prospective double-blinded randomised controlled trial. indian j. anaesth. 2018;62(7): 524-530. doi: 10.4103/ija.ija_788_17. 3. khurshid h, muneer k, malla hs. effect of dexmedetomidine on emergence agitation after nasal surgeries. j med sci clin res. 2015;2(3):126-130. doi: 10.5958/2394-4994.2015.00013.x 4. kim sy, kim jm, lee jh, song bm, koo bn. efficacy of intraoperative dexmedetomidine infusion on emergence agitation and quality of recovery after nasal surgery. br j. anaesth. 2013;111(2): 222-228. doi:10.1093/bja/aet056 5. polat r, peker k, baran i, aydin gb, guloksuz ct, donmez a. comparison between dexmedetomidine and remifentanil infusion in emergence agitation during recovery after nasal surgery: a randomized double-blind trial. anaesthesist. 2015;64(10): 740-746. doi: 10.1007/s00101-015-0077-8 6. xu k, tiwari rl, pan y, zhu m. effects of dexmedetomidine on the recovery profiles from general anesthesia in patients undergoing endoscopic sinus surgery. int j clin exp med. 2016;9(5): 8405-8410. conclusions • intraoperative dexmedetomidine is a safe and effective anesthetic adjunct that significantly decreases the incidence of ed compared to receiving a placebo • loading dose of dexmedetomidine 1 mcg/kg bolus followed by maintenance infusion 0.4 mcg/kg/h after induction provided the greatest attenuation of ed. • secondary positive effects, such as hemodynamic stability, analgesia, and decreased antiemetic requirements, were observed, but these qualities need to be further studied with an appropriate sample population • overall, dexmedetomidine facilitated a smoother emergence from general anesthesia without any complications • since there are no absolute contraindications to dexmedetomidine, further research should explore how patients classified as > asa ii may benefit from this anesthetic technique • future studies should compare the effects of intraoperative dexmedetomidine at different dosages to standardize the anesthesia regimen • although ed is typically seen immediately after extubation, further research is needed to determine long-term outcomes of dexmedetomidine case summary pre-anesthetic evaluation • 19-year-old, 98 kg, 180 cm, male presented for septoplasty • medical history: no significant past medical history • pre-op medications: acetaminophen 650 mg, gabapentin 300 mg • vital signs: hr 72, bp 131/77 (95) mmhg, spo2 98%, rr 18 intraoperative course • induction: lidocaine 100 mg, propofol 300 mg, rocuronium 30 mg • ett 8.0 via direct laryngoscopy • maintenance: sevoflurane 1.2-1.6% end-tidal concentration, 1 l/min oxygen, 1 l/min medical air • emergence: sevoflurane 0%, neostigmine 3 mg iv, glycopyrrolate 0.6 mg iv, fentanyl 50 mcg, ondansetron 4 mg iv, ketorolac 30 mg iv postoperative course • extubated under positive pressure, 10 l/min of oxygen of fresh gas flow, became dangerously agitated, non-cooperative, thrashed his arms and legs and became hypoxic • vital signs: hr 114, bp 151/99 (116) mmhg, spo2 77%, rr 33 • staff restrained him and attempted to verbally reminded him he was in the or • sedated with propofol 50 mg iv and lidocaine 50 mg iv to facilitate bag-mask ventilation and correct the hypoxia figure 1. adapted from kim et al4 table 2. adapted from kim et al4 table 1. adapted from kim et al4 figure 2. adapted from kim et al4 volume 8no. 5 2020 educated hand publishing llc “the science behind the art” volume 8 no.5 2020 anesthesia ejournal online issn 2333-2611 page 14 perioperative dexmedetomidine for analgesia during burn excision and grafting amy ybarra, bsn, rn affiliation: texas christian university funding/conflict of interest disclosure: none keywords: burn anesthesia; burn analgesia; dexmedetomidine abstract patients with superficial burns normally do not require surgical intervention, however, burns that are deep and large, require numerous procedures for excision and skin grafting (eg).1 one of the challenges with these patients lies in their multi-faceted, but common theme of pain, which is confounded not only by high inter-patient variability and unpredictability1, 2 , but by pain from the initial injury, by wound care pain and by the new, postoperative pain from eg procedures.1 this case report details the utilization of dexmedetomidine as an adjunct for analgesia during eg for a severely burned patient. findings are consistent with the evidence and reveal on the day dexmedetomidine was used, the patient had lower post-operative pain scores, lower postoperative richmond agitation sedation scores (rass), and it was the only day the patient did not require any postoperative prn pain medication administration. although limited evidence exists specifically related to the use of intraoperative dexmedetomidine for eg of severe burns, this case report suggests a promising role for the addition of this a2 agonist as a multi-modal approach to caring for this complex population. aej educated hand publishing llc “the science behind the art” volume 8 no.5 2020 anesthesia ejournal online issn 2333-2611 page 15 powerpoint template ©2009 texas christian university, center for instructional services. for educational use only. content is the property of the presenter and their resources. introduction • pain is a common factor among burn patients1 • burn pain is multifaceted; includes initial injury pain, wound care pain, new pain from excision and grafting (eg)1 • burn pain produces both hyperalgesia and allodynia2 • increasing narcotic doses and tolerance is common but may fail to provide adequate relief and may result in opioid-induced hyperalgesia1,2,3 research • there is limited research. one study details dexmedetomidine intraoperatively for eg, 4 others detail its use for burn wound care sedation or non-burn care. • provided enhanced analgesia, decreased surgical stress response, reduction of total opioid consumption in non-burn surgical patients.4 • produced positive patient perception, decreased post-operative pain and opioid requirements in moderately burned patient study.4 • produced improved sedation and thus better tolerated burn wound care in pediatric burn patients.5 dexmedetomidine • alpha-2 adrenergic agonist6 • acts on preganglionic sympathetic neurons resulting in inhibition of norepinephrine release.6 • highly selective for α2 receptors, numerous in locus ceruleus which plays major role in regulation of memory, arousal, analgesia.4,6 • produces sympatholysis, analgesia, sedation.6 • side effects include bradycardia and hypotension, worse with hypovolemia.2,6 • decreases mac requirements, opioid requirements, surgical stress response, plasma catecholamine concentrations during anesthesia.4,6 discussion and conclusions • the excision and grafting detailed for this case report (red outline) was the most extensive eg in this series, including the entirety of bilateral buttocks, lower back, as well as circumferential excision and grafting of bilateral lower extremities from below the ankles to upper thighs. • in order to minimize data skew from physiologic changes, compared cases were limited to a 20-day timeframe, 9 days prior to and 11 days after the detailed case report procedure. eg sites compared in table. • anesthesia and post-operative records were compared from time of initial preoperative medication with midazolam through midnight on same operative day. • 1 of 5 excision and grafting procedures compared incorporated dexmedetomidine. • patient exhibited signs of stimulation only one time during the 5-hour procedure, and was medicated with dexmedetomidine 5 mcg and dilaudid 0.5 mg. • postoperative pain scores and richmond agitation-sedation scale (rass) were lower with dexmedetomidine. • no additional postoperative analgesia was required through midnight on operative day when intraoperative dexmedetomidine was used. mechanism of action case report patient information • 26-year-old female with a 1-month history of 2nd and 3rd degree burns over 95% of her total body surface area • asa 3, 70kg • patient had undergone approximately 14 escharotomies and/or excision and grafting procedures in the 6 weeks between her admission and the last compared surgical procedure. • each surgical procedure compared in the case report involved excision and grafting of different but similar sites, detailed in the table above. procedure for case report (red outline) was the most extensive. anesthetic management • balanced anesthetic included preoperative midazolam, maintenance sevoflurane, and rocuronium. • dexmedetomidine infusion of 0.3mcg/kg/hr was started immediately after induction and discontinued approximately 2 minutes prior to end of procedure. patient received a total of 175 mcg per infusion. • additional intraoperative analgesics included ketamine 10 mg every hour for a total of 30 mg, 50 mcg fentanyl prior to each major surgical stimulation for a total of 100mcg, and a one-time dose of dilaudid 0.5 mg with dexmedetomidine 5 mcg for signs of stimulation. • total surgery time was approximately 5 hours. procedure comparison perioperative dexmedetomidine for analgesia during burn excision and grafting amy ybarra, bsn, rn, texas christian university references 1. ray de, karlekar mb, crouse dl, et al. care of the critically ill burn patient. ann am thorac soc. 2017;12(7):1094-1102. doi: 10.1513/annalsats.201607-577ps 2. bittner e, shank e, woodson l, martyn j. acute and perioperative care of the burn-injured patient. anesthesiology. 2015;122(2):448-464. doi: 10.1097/aln.0000000000000559 3. retrouvey h, shahrokhi s. pain and the thermally injured patient—a review of current therapies. journal of burn care & research. 2015;36(2):315-323. doi: 10.1097/bcr.0000000000000073 4. jiang, m, sun q, liu g, qu h, ma j. efficacy of dexmedetomidine in reducing post-operative pain and improving the quality of recovery in patients with burn wounds undergoing tangential excision skin grafting. experimental and therapeutic medicine.2019;17:1776-1782. doi:10.3892/etm.2019.7155 5. pardesi o, fuzaylov g. pain management in pediatric burn patients: review of recent literature and future directions. journal of burn care & research. 2017;38(6): 335-347. doi: 10.1097/bcr.0000000000000470 6. flood p, rathmell j, shafer s. stoelting’s pharmacology and physiology in anesthetic practice. philadelphia, pa: wolters kluwer health; 2015. 7. sanders rd, maze m. alpha2-agonists and other sedatives and amnestics. in: evers as, maze m, kharasch ed, eds. anesthetic pharmoacolgy: basic principles and clinical practice. 2nd ed. cambridge: cambridge university press; 2011:478-492. doi:10.1017/cbo9780511781933.031 7 volume 6 no. 9 2018 educated hand publishing llc “the science behind the art” volume 6 no. 9 2018 anesthesia ejournal online issn 2333-2611 page 41 contributions of south korean registered nurses in anesthesia practice michong rayborn, dnp, crna1 gyeseon jeong, phd, crna2 hwanseok choi, phd1 satananda hayden, phd, msn, rn3 1 affiliation: dr rayborn is corresponding author and assistant professor at university of southern mississippi, hattiesburg 2dr jeong is co-corresponding author and assistant professor in the chosun college nursing, kwang ju, south korea 3dr hayden is director of clinical information systems, forrest general hospital, hattiesburg, mississippi funding/conflict of interest disclosure: this study received a grant from the international federation of nurse anesthetists (ifna) foundation research grant 2017. discussion: rnas are an integral part of anesthesia services in korea, although they are not certified and lack clear scope of practice. the authors recommend a pathway for rnas to obtain advanced degrees and certification as anesthesia providers. keywords: certified registered nurse anesthetist (crna), registered nurse in anesthesia (rna), scope of practice, elements of anesthesia care introduction globally, nurses today are involved in a variety of anesthesia practices.1 south korea is not an exception; however, there are currently not enough certified registered nurse anesthetists (crnas) to meet the country’s need. to overcome the shortfall, registered nurses (rns) are trained by anesthesiologists in their hospital workplace to provide anesthesia-related services. however, these trained rns lack certification by national examination.2 this study assessed rn and crna involvement in providing anesthesia care in south korea, the degree of autonomy of these nurse anesthesia providers, and the presence of a scope of practice or guidelines for providing anesthesia. a previous study examined the contributions of both crnas and uncertified rns in south korea. several startling facts were revealed regarding south korean nurse anesthesia practice.2 the authors noticed that the number of practicing crnas was declining in the country. only one university in the country currently offered a graduate crna program. the authors also discovered that, to meet the provider shortfall, hospitals often trained rns in-house to provide anesthesia services.2 abstract introduction: certified registered nurse anesthetists (crnas) were recognized by law as legitimate anesthesia providers in korea 44 years ago. since 2005, crnas have been educated at the graduate level and certified by national examination. in recent years, the number of graduate educational programs has decreased and the number of practicing crnas has declined correspondingly. to meet the shortfall, hospitals train registered nurses to perform anesthesia. this study examined registered nurses in anesthesia (rnas) and crnas in anesthesia care in south korea. materials and methods: a confidential survey was administered to a sample of 308 nurses in anesthesia practice. the chi-square independent test and independent two-sample t-test for continuous variables were used for comparison. results: while all were involved in anesthesia, rnas were more likely to work under supervision. almost 34% of the participants planned to leave anesthesia practice within the next 5 years, and nearly 20% of participants indicated that they planned to retire within 5 years. aej anesthesia ejournal www.anesthesiaejournal.com volume 6 no.9 2018 page 42 nurse anesthesia practice in south korea has its roots in the aftermath of the korean war. at that time there was a critical need for anesthesia services due to the many military and civilian war injuries, as well as from refugees flooding the country from the north.2-4 there were only a limited number of anesthesiologists in the country, and the korean military trained the first nurse anesthetists in 1961 to help meet the shortfall.2-5 one of the most influential advocates for nurse anesthesia in the country at that time was an american woman named sister margaret kollmer. she arrived in the country in 1964 as a young crna assigned to maryknoll hospital in pusan, south korea. recognizing a lack of anesthesia providers in country, she decided to create a program to train rns as anesthetists. in 1969 she implemented a training program in hospitals. the programs were based on the american educational model and consisted of 18 months of training and supervised practice.2 the crnas were certified by the hospital where they trained. for the next 29 years sister margaret was the most ardent promoter of nurse anesthesia in korea.2 but the journey has not always been smooth and there are still many bumps along the road. her efforts were rewarded in 1973 when the ministry of health and welfare formally recognized anesthesia practice by crnas. at that time, a total of 13 hospitals trained crnas. however, the number of hospital-based crna training programs gradually declined over the years.2,3,5 in 2003, south korean national law recognized crnas as legitimate advanced practice nurses. the same year, 2 graduate-level university crna education programs were established. however, one university crna program closed soon afterward. in 2005, the ministry of health and welfare required all new crnas to earn a master’s degree from an accredited university and to pass a national certification examination.2,4,5 now, 45 years after the ministry of health and welfare recognized the practice, the number of graduate-level crna educational programs has declined sharply and the number of practicing crnas has decreased correspondingly.2-6 today, only one university offers a graduate degree in nurse anesthesia and that program produces about only 10 crnas each year.2-5 in a country of 51 million citizens, that is hardly enough to meet the need. since the demand for anesthesia services has not diminished, hospitals in korea have looked for an alternate way to meet the shortage of crnas and medical residents. rns are often trained on the job as anesthesia providers. although these nurses are trained by the anesthesiologists at the hospital where they work, there are no standard training guidelines or established scope of practice. most importantly, these rns are not certified as anesthesia providers by a national examination.4,5 here we will refer to these uncertified anesthesia providers as registered nurses in anesthesia (rnas) to differentiate them from crnas. depending on the level of training they receive and the location of their practice, these rnas practice under many different job titles. generally, these nurses are referred to as either specialty nurses ( jeon dam nurses) or as peri-anesthesia department nurses.7 specialty nurse ( jeon dam nurse) nurses commonly known as specialty nurses ( jeon dam in korea) practice a medical specialty or delegated medical tasks or services under a physician’s license.7,8 most of these specialty nurses are not advanced practice nurses and they are not required to pass a certification examination by the ministry of health and welfare. in 2014, there were an estimated 2220 specialty nurses working in different specialties at hospitals throughout the country. since there are no standard guidelines for training and scope of practice, the roles of specialty nurses are often confused by the medical community. only 14% of specialty nurses are advanced practice nurses.7,8 the result is a unique situation that fosters confusion about the identity of these nurses as health care providers, as well as their level of training and scope of practice.7 we will refer here to specialty nurses who practice anesthesia as anesthesia specialty nurses (asns). peri-anesthesia department nurses in addition to asns, peri-anesthesia department nurses are also trained in the hospital where they practice. like the asns, the peri-anesthesia department nurse is also deeply involved in anesthesia practice. depending on the location of their practice, they may be referred to as anesthesia department nurses, operating room nurses, or recovery room nurses.7 like the specialty nurses, these nurses do not receive formal university anesthesia training and are not required to pass a certification examination. they practice various levels of anesthesia under physician supervision. the korean association of nurse anesthetists there is a professional organization in place for nurse anesthetists in korea. shortly after successfully lobbying of the ministry of health and welfare for recognition of crnas, sister margaret kollmer realized the need for a professional organization.2-5 she was the catalyst in the formation of the korean association of nurse anesthetists (kana). modeled after the american association of nurse anesthetists (aana), kana is an advocate for the advancement of nurse anesthetists and for patient safety. today, kana membership is open to both crnas and rnas.2 it is easy to understand the confusion regarding rnas in korea, with so many different job titles and the absence of specific guidelines for training and practice. although there are many korean studies examining the role of specialty nurses, there are no current studies that have focused specifically on anesthesia practice by asns or peri-anesthesia department nurses.7-10 depending on level of training and location of employment, rnas are involved in various levels of anesthesia services, including administering anesthesia. however, unlike crnas, the exact number of rnas is not known and their scope of practice is not clear. this leads to confusion between roles of rnas and crnas. purpose of research the purpose of this study was to assess the involvement of rns including rnas and crnas in anesthesia care in south korea. to achieve this purpose, we sought to determine which elements of anesthesia practice these rnas and crnas are performing. additionally, we examined whether these nurse anesthesia providers are engaging under direct supervision by anesthesiologists and surgeons or whether they practice with some degree of autonomy. the other desired outcome was to determine whether there is a defined scope of practice for these 2 levels of nurse anesthesia providers. finally, this study highlights the contributions of nurses to anesthesia practice in korea. the aim was to provide information anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 9 2018 page 43 that may help to establish guidelines to develop the scope of practice for the different levels of nurse anesthesia providers. we also advocate for reestablishing and strengthening graduate-level education for crnas so they may reach their full potential as advanced practice nurses. background anesthesia providers and scope of practice in the united states in the united states, anesthesia services can be provided by either physician anesthesiologists, crnas, or anesthesiology assistants (aas). these 3 groups are the only professionals qualified to administer anesthesia. their scopes of practice are clearly defined and all are certified by their governing body after completing graduate-level education. this system is structured and governed to ensure public safety and to protect the profession.11 physician anesthesiologist physician anesthesiologists are medical doctors who specialize in anesthesia practice. after undergraduate school, they complete 4 years of medical school to earn either a doctor of medicine (md) degree or a doctor of osteopathic medicine (do) degree. upon completing a 4-year residency, physicians are eligible to sit for the american board of anesthesiology (aba) examination. according to the american society of anesthesiologists, about 75% of anesthesiologists are board-certified.12 in 2017 there were 46,971 anesthesiologists practicing in the united states.13 anesthesiology assistant aas work under direction from licensed anesthesiologists.12,14 to earn certification, they must complete a 4-year undergraduate degree and satisfactorily complete an accredited aa graduate education program and pass the national commission for certification of anesthesiologist assistants (nccaa) examination. the national board of medical examiners (nbme) provides performance information for the test. according to the nccaa, there are approximately 2300 aas currently practicing in the united states (nccaa, email communication, march 27, 2018) certified registered nurse anesthetist nurse anesthetists have practiced in the united states for more than 150 years, dating back to the american civil war. they were the first recognized advanced practice nursing specialty and were first credentialed in 1956. when anesthesia is administered by a nurse anesthetist, it is recognized as the practice of nursing, whereas anesthesia administered by a physician anesthesiologist is recognized as the practice of medicine.15,16 crnas administer approximately 43 million anesthetics to patients each year in the united states. there are approximately 52,000 crnas practicing in the united states today.16 crnas in the united states are educated at either the master’s or doctoral level under strict guidelines established by the council on accreditation of nurse anesthesia educational programs (coa). after completing a graduate of nurse anesthesia educational program, they must pass the national certification examination (nce). crnas are required to recertify every 8 years through the continued professional certification (cpc) program, which is administered by the national board of certification and recertification for nurse anesthetists (nbcrna).11,16 most importantly, all us anesthesia providers must complete an accredited educational program at either the master’s, doctoral, or physician level. all crnas, aas, and most physician anesthesiologists are certified by national examination and all practice under clearly established scopes of practice. the level of autonomous practice may vary from state to state.16 however, such is not necessarily the case in south korea. there, anesthesia providers may be either board-certified physicians or crnas, but may also be rnas who have not completed graduate-level anesthesia training or passed a board-administered certifying examination. the disparity between training and practice guidelines for nurse anesthetists in the united states and korea was the catalyst for this study. scope of practice and application to this study there are 4 essential elements of anesthesia care: pre-anesthetic evaluation and preparation of equipment and anesthetic drugs; anesthesia induction, maintenance, and emergence; post-anesthesia care; and peri-anesthetic support functions.11 each element of anesthesia is vital for successful anesthesia performance and positive patient outcomes. a misstep or miscalculation in any area may have detrimental consequences for the patient.11 we identified 9 specific anesthesia-related tasks to examine as the basis of the study. the 9 tasks were as follows: pre-anesthetic assessment, prescribing an anesthetic plan, checking the anesthesia machine and required materials, administering or injecting induction agents, inserting an endotracheal tube, managing emergence from anesthesia and deciding when to remove the endotracheal tube, post-anesthetic and pain management, performing regional blocks, and documenting anesthesia notes. all 4 essential elements and all 9 anesthesia tasks were evaluated during this study. materials and methods data collection and procedures this study was conducted with approval from the university of southern mississippi institutional review board and with support from the kana. it was a follow-up to a similar study conducted by surveying kana members in 2015.2 the survey questions were adapted from a 2014 membership profile survey developed and administered by the aana. with a few modifications, a total of 17 revised survey questions were designed to obtain sociodemographic information and detailed status of the level of anesthesia practice by rns in south korea. the survey questions were translated into the korean language. the translation and cultural accommodations were validated by south korean crnas currently practicing in the united states, as well as by crnas and rnas in south korea (table 1).2 the survey was administered confidentially via both email and post mail to rnas and crnas in 3 cities (seoul, incheon, and kawang-ju) and 3 different provinces (kyong-gi province, kyoung-sang province, and jeol-ra province) from march 18 to september 30, 2017. participation was voluntary and informed consent was verified when respondents completed and submitted the survey. respondents submitting the survey with 50% or more of the questions unanswered were considered to have withdrawn their consent to participate, and their responses were removed from the study. a total of 325 surveys were returned, and among those, 308 surveys were included in the study. all data collected and used for this study remained anonymous. https://en.wikipedia.org/wiki/medical_school https://en.wikipedia.org/wiki/doctor_of_medicine https://en.wikipedia.org/wiki/doctor_of_osteopathic_medicine https://en.wikipedia.org/wiki/residency_(medicine) anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 9 2018 page 44 data analysis descriptive statistics were used to identify the characteristics of the participants. the chi-square independent test for categorical variables and the independent two-sample t-test for continuous variables were performed using sas 9.3 (sas institute inc) to compare components of practice between crnas and rnas. results a total of 308 respondents were included in the study. the respondents’ mean age was 33.53 years (sd = 7.95 years), and the average years of experience was 8.34 years (sd = 7.2 years). more than 85% of the respondents had bachelor’s degrees or less (n=267; 86.69%), while only 21 (6.81%) had master’s degrees or higher. almost all of them worked full-time (n=302; 98.05%). around 67% of the participants (n=193) were working in a university hospital with more than 300 beds, whereas only about 10% (n=29) worked in hospitals with fewer than 100 beds. from the total sample, only 42 respondents identified themselves as crnas (13.64%), whereas 266 identified themselves as rnas (86.36%). the rnas worked under a number of different job titles, such as anesthesia department nurse (n=152), anesthesia specialty nurse (n=14), recovery room nurse (n=89), and operating room nurse (n=11). among rnas, more than half indicated they would like to pursue graduate-level education to become crnas (n=171; 55.52%). interestingly, almost 34% of the participants planned to leave anesthesia practice within the next 5 years, before they are eligible for retirement (n=104; 33.76%). in addition, almost 20 % of participants indicated they plan to retire within 5 years (n=60; 19.49%) (table 2). table 3 shows the chi-square test results between crnas and rnas for 4 separate variables: hospital size, education level, age, and years of experience. according to the chi-square test results, the 2 groups had different percentages in each category (x2 = 37.86; p < 0.001). rnas were working mostly in the larger hospital (92.8%), while more than half of the crnas were working in mid-size hospitals or hospitals with fewer than 100 beds (73.8%). almost half of the crnas had at least a master’s degree, whereas the majority of the rnas had bachelor’s degrees or less (92.2%). for the continuous variables such as age and years of experience, t-tests were performed. as expected, the crnas were older and more experienced (42.3 years old and 15.8 years of experience) than were the rnas (32.1 years old and 7.2 years of experience). satterthwaite t-tests were done in case the equal variance assumption was violated (table 3). table 4 compares jobs and tasks between the 2 groups. there were no significant differences between the 2 groups in the percentage of time spent on clinical activities, education, management/ administration, research, and consultation. the variable labeled “anesthesia practice” looked at 9 anesthesia tasks selected by the authors. crnas were significantly more involved in 5 of the 9 tasks (prescribe anesthetic plan, insert endotracheal tube and laryngeal mask airway, manage emergence from anesthesia and decision to remove endotracheal tube, post-anesthetic management, and perform regional blocks). the other tasks that were not statistically significant also had more percentages of crnas involved. there was a statistically significant difference in the level of physician supervision between the 2 groups (x2 = 9.548; p = 0.002). rnas were more likely to work under supervision (n=224; 84.2%) than were crnas (n=27; 64.3%). for most of the anesthesia activities, rnas were supervised by the anesthesiologist more often, except for performing post-anesthetic assessment and periodically monitoring anesthetic course. surgeon involvement in anesthesia practice was not statistically significant, regardless of whether they were certified (x2 = 0.877; p =0.349) (table 4). table 5 highlights the lack of standardized scope of practice for rnas. in this table, the rnas are separated depending on the job title they worked under. these job titles are anesthesia department nurse (n=152), anesthesia specialty nurse (n=14), recovery room nurse (n=89), and operating room nurse (n=11). this table makes it clear that the rnas, by any title, were involved in the same 9 anesthesia tasks as the crnas. for example, 13 of the 14 (92.6%) respondents who identified as asns routinely injected induction drugs. interestingly, of the 89 respondents who identified as recovery room nurses, 78 (87.6%) injected induction drugs, 19 (21.3%) performed intubation, and 4 (4.5%) personally performed regional blocks. clearly, these 4 categories of rnas were involved in a wide range of anesthesia tasks, but without a standardized scope of practice (table 5). discussion the data analysis points to 4 important trends regarding the future of rnas in korea’s health care system. first, there is a great need for their services. with only one university graduate program producing 10 or fewer crnas per year,4 the country must fill the provider gap, and rnas help to meet the need. second, rnas currently are involved in all 4 anesthesia essential elements to varying degrees. in fact, there was no significant difference in the time spent on clinical practice, education, research, or administrative tasks between the 2 groups, but crnas did tend to spend more time on patient consultation. furthermore, rnas were also involved in performing all 9 anesthesia tasks, although crnas were likely to be more involved in each task. third, although most rnas held only a bachelor’s degree or less, almost 56% indicated that they would like to pursue an advanced degree as a crna. however, graduate opportunities to progress from rna to crna are very limited. the fourth trend is that rnas worked under different job titles, which may imply they are not recognized properly as anesthesia providers. despite the lack of recognition by job title, rnas are involved in all elements of anesthesia practice. the combination of these trends leads us to conclude that an educational pathway from rna to crna would be beneficial to both individual practitioners and the health care system in korea. there are also several interesting trends regarding crnas. first, crnas describe greater independence in anesthesia practice than do rnas. as a percentage of the sample, they are also significantly more involved in the 9 anesthesia tasks and the 4 elements of anesthesia practice. this is reasonable because they are certified, tend to be older, have more years of experience, and are more likely to hold advanced degrees. however, the number of practicing crnas is declining and the one remaining graduate-level educational program is not likely to replace the numbers lost through attrition. the rnas are working mostly in large university hospitals (92.8%) and perform most anesthesia activities under anesthesiologist supervision. more than half of the crnas work in midsized hospitals or hospitals with fewer than 100 beds (73.8%). this result mirrors the findings of bae et al, who compared the job task and task elements of korean nurse anesthetists by the size of the medical institution.6 crnas are more likely to work without an anesthesiologist’s supervision. alarmingly, almost 34% of participants plan to leave anesthesia practice before retirement within 5 years (n=104; 33.76%). also, almost 20% of nurses practicing anesthesia are expected to retire within 5 years (n=60; 19.49%), which exacerbates the critical nurse anesthesia shortage. on the basis of this survey, we could expect tremendous shortages of anesthesia nurses whether they are certified or not within 5 years. we are not sure why one-third of practitioners want to leave anesthesia before their permanent retirement from nursing. one possible reason is the lack of a pathway to advanced education for rnas. the results of our study suggest that rnas are an integral part of anesthesia services in korea. our major concerns are that rnas do not have required certifications for nurse anesthesia and there are no clear standards for their education and scope of practice. as a possible solution, we recommend a university-led effort to provide an educational pathway for rnas to obtain advanced nursing degrees and certification as anesthesia providers. any such educational program should provide clear guidelines for training and for the scope of practice. this would require the support of not only the universities, but also the hospitals, anesthesiologists, and possibly the national legislature. as an advocate for patient safety, kana is the most logical organization to lead the campaign to implement such a program. this would be the first step to ensuring a ready supply of highly qualified nurse anesthetists to meet the country’s future need. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 9 2018 page 45 references 1. mcauliffe ms, henry b. countries where anesthesia is administered by nurses.  aana j. 1996;64(5):469-479. 2. rayborn m, jeong g, hayden s, park s. the future of certified registered nurse anesthetists in south korea: fading into the sunset or breaking of a new dawn. aana j. 2017;85(5):361-367. 3. kim s. t he beginning & change of the korean anesthesia nursing [phd thesis]. pusan, republic of korea: catholic university of pusan; 2014:1-114. 4. history of korean certified registered nurse anesthetists. korean association of nurse anesthetists (kana).  http:// www.korea-ana.co.kr/v3/sub2_01.php. published 2015. accessed feb 1, 2018. 5. shin sr, oh pj. a study on the demand for nurse anesthetists in korea. j korean acad fundam nurs. 2004;11(2):195-202. 6. bai c, yoon h. comparison of job task and task elements of korean nurse anesthetists by the type of medical institution: hospital, general hospital and higher general hospital.  j korean acad nurse adm. 2013;19(2):239-253. https://doi. org/10.11111/jkana.2013.19.2.239. 7. kwak c-y, park j-a. current roles and administrative facts of the korean physician assistant. journal of the korea contents association. 2014;14(10):583-595. https://doi.org/10.5392/jkca.2014.14.10.583. 8. cho ms, cho ya, kwon ig, seo mj, baek hj. importance, satisfaction and contribution of advanced practice nurses’ role recognized by health care professionals. j korean acad nurs adm. 2011;17(2):168-179. https://doi.org/10.11111/ jkana.2011.17.2.168. 9. lee hj. role adoption process for physician assistant. asia-pacific journal of multimedia services convergent with art, humanities, and sociology. 2017;7(4):941-957. https://doi.org/10.14257/ajmahs.2017.04.86. 10. kim mj, sohn d, jeung me, kang is. perception of healthcare providers on physician assistant’s job. research institute of nursing science, pusan national university; 2015:5(1). 11. foster s, faut-callahan m. a professional study and resource guide for the crna.  park ridge, il: aana publishing; 2014. 12. about the profession. american society of anesthesiologists. https://www.asahq.org/for-the-public-and-media/aboutprofession.aspx. accessed november 22, 2017. 13. number of active physicians in the u.s. in 2017, by specialty area. statista. https://www.statista.com/statistics/209424/usnumber-of-active-physicians-by-specialty-area/. accessed november 22, 2017. 14. american association of nurse anesthetists. comparison of certified registered nurse anesthetists (crnas) and anesthesiologist assistants (aas). https://iowacrnas.com/wp-content/uploads/2017/03/crna-aa-comparison-tableupdate-102014-1.pdf. accessed november 26, 2017. 15. bankert m. watchful care: a history of america’s nurse anesthetists. new york: continuum publishing company; 1989:164. 16. american association of nurse anesthetists. certified registered nurse anesthetists fact sheet. https://www.aana.com/ membership/become-a-crna/crna-fact-sheet. updated october 10, 2017. accessed april 13, 2018. anesthesia ejournal www.anesthesiaejournal.com volume 6 no.9 2018 page 46 http://www.korea-ana.co.kr/v3/sub2_01.php http://www.korea-ana.co.kr/v3/sub2_01.php https://doi.org/10.11111/jkana.2013.19.2.239 https://doi.org/10.11111/jkana.2013.19.2.239 https://doi.org/10.5392/jkca.2014.14.10.583 https://doi.org/10.11111/jkana.2011.17.2.168 https://doi.org/10.11111/jkana.2011.17.2.168 https://doi.org/10.14257/ajmahs.2017.04.86 https://www.asahq.org/for-the-public-and-media/about-profession.aspx https://www.asahq.org/for-the-public-and-media/about-profession.aspx https://www.statista.com/statistics/209424/us-number-of-active-physicians-by-specialty-area/ https://www.statista.com/statistics/209424/us-number-of-active-physicians-by-specialty-area/ https://iowacrnas.com/wp-content/uploads/2017/03/crna-aa-comparison-table-update-102014-1.pdf https://iowacrnas.com/wp-content/uploads/2017/03/crna-aa-comparison-table-update-102014-1.pdf https://www.aana.com/membership/become-a-crna/crna-fact-sheet https://www.aana.com/membership/become-a-crna/crna-fact-sheet table 1. korean nurse anesthetist survey questionnaire 1. what is your job title in your organization? a. certified registered nurse anesthetist b. anesthesia department nurse c. anesthesia specialty nurse d. recovery room nurse e. operating room nurse 2. indicate your current employment status a. full-time (> 35 hours per week) b. part-time 3. indicate where is your anesthesia practicing setting a. university hospital (more than 300 hospital beds) b. middle sized hospital (100-300 hospital beds) c. freestanding surgical center (outpatient center) d. doctor’s office/clinic 4. indicate the percentage of time you spend in each of the following positions (the total must add to 100%) a. clinical practice b. education c. department management/administration d. research e. consultation 5. what year you were born? (age) 6. please mark your highest levels of education completed a. associated/diploma b. baccalaureate in nursing d. master’s in anesthesia e. doctorate 7. do you have nurse anesthesia certification? if you do, where was it obtained? a. no, i do not have nurse anesthesia certification b. associated /diploma c. baccalaureate in nursing d. master’s in anesthesia a. 1 year or less 8. do you like pursue university graduate level education to be a certified registered nurse anesthetists? a. yes b. no 9. how long have you been practicing as a nurse anesthetist? b. 2-5 years c. 6-10 years d. 11-20 years e. 21-30 years f. 31 or more years 10. what year do you plan to leave anesthesia practice before your complete retirement from nursing practice? a. spinal 11. what year do you expect to retire completely from nursing practice? 12. check all that you do following anesthesia hand on practice: a. pre-anesthetic assessment b. prescribe anesthetic plan c. prepare anesthetic material and check anesthesia machine d. injections anesthetic drugs during induction e. insertion endotracheal tube and laryngeal mask airway f. managing of emerging, and decision of removal of airway g. post anesthetic management include pain management h. personally perform regional blocks i. documentation of anesthesia note 13. check all that you do following anesthesia hand on practice: b. epidural c. bier d. brachial plexus e. femoral f. popliteal-saphenous g. ankle block 14. do you work in an anesthesia practice, where the anesthesiologist supervises the nurse anesthetist? 15. of the anesthetics you personally administer, how often is an anesthesiologist involved in the following anesthesia activities? a. pre-anesthetic assessment b. prescribe anesthetic plan c. present at induction d. present for emergencies or urgent situations e. present for emerging from anesthesia f. perform post-anesthetic assessment g. periodically monitor anesthetic course 16. do you work in an anesthesia practice, where the surgeon supervises the nurse anesthetist? 17. of the anesthetics you personally administer, how often is a surgeon involved in the following anesthesia activities? 18. same as 15. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 9 2018 page 47 table 2. descriptive statistics (n = 308) variable no. (%) mean (sd) crna yes no 42 (13.64) 266 (86.36) full-time yes no 302 (98.05) 6 (1.95) age 33.53 (7.95) years of experience 8.34 (7.16) education associate ba in nursing ba in other fields ma in nursing ma in anesthesia ma in other fields doctorate 72 (23.38) 193 (62.66) 2 (0.65) 20 (6.49) 17 (5.52) 3 (0.97) 1 (0.32) job title crna anesthesia department nurse anesthesia specialty nurse recovery room nurse operating room nurse 42 (13.64) 152 (49.35) 14 (4.55) 89 (28.90) 11 (3.57) working hospital size university hospital (>300 beds) middle-sized hospital (100–300 beds) freestanding surgical center (<100 beds) doctor’s office/clinic 193 (67.25) 65 (22.65) 23 (8.01) 6 (2.09) would you like to pursue university graduate-level education to be a certified registered nurse anesthetist? yes no 171 (55.52) 137 (44.48) when do you plan to leave anesthesia practice before your retirement from nursing practice? 2017 to 2019 2020 to 2022 after 2022 31 (10.06) 73 (23.7) 204 (66.23) when do you expect to retire completely from nursing practice? 2017 to 2019 2019 to 2022 after 2022 14 (4.55) 46 (14.94) 248 (80.52) abbreviation: crna, certified registered nurse anesthetist. anesthesia ejournal www.anesthesiaejournal.com volume 6 no.9 2018 page 48 table 3. bivariate analyses between crnas and rnas variable certified group (crnas) non-certified group (rnas) test test statistic p working hospital size, no. (%) university hospital (>300 beds) middle-sized hospital (100–300 beds) freestanding surgical center (<100 beds) doctor’s office/clinic 11 (26.2) 16 (38.1) 12 (28.6) 3 (7.1) 186 (69.9) 61 (22.9) 14 (5.3) 5 (1.9) χ2 * 37.856 < 0.0001 education, no. (%) associate ba in nursing ba in other fields ma in nursing ma in anesthesia ma in other fields doctorate 8 (19.1) 14 (33.3) 0 (0.0) 5 (11.9) 14 (33.3) 0 (0.0) 1 (2.4) 64 (24.1) 179 (67.3) 2 (0.8) 15 (5.6) 3 (1.1) 3 (1.1) 0 χ2 * 43.299 < 0.0001 age, y, mean (sd) 42.31 (8.28) 32.14 (6.97) t-test 8.56 < 0.0001 years of experience, mean (sd) 15.76 (8.34) 7.16 (6.20) t-test** 6.41 < 0.0001 abbreviations: crna, certified registered nurse anesthetist; rna, registered nurse in anesthesia. *due to the lack of cell frequencies, cochran-mantel-haenszel (cmh) chi-square test was done. **due to the equal variance assumption violation, satterthwaite t-test statistic was applied. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 9 2018 page 49 table 4. comparison of jobs and tasks between crnas and rnas variable crnas rnas test test statistic p percentage of time spent, %, mean (sd) clinical practice education management/administration research consultation other 77.3 (23.5) 7.3 (6.7) 11.6 (16.4) 1.31 (3.1) 1.31 (3.1) 1.19 (3.1) 81.2 (20.5) 7.4 (9.2) 8.5 (15.0) 0.73 (2.4) 0.72 (2.2) 1.34 (3.4) t-test t-test* t-test t-test* t-test* t-test 1.14 0.02 1.24 1.14 1.18 0.27 0.25 0.98 0.21 0.26 0.24 0.79 anesthesia practice, no. (%) pre-anesthetic assessment prescribe anesthetic plan check anesthesia machine and material injections of induction drugs insertion endotracheal tube managing of emergence and decision of removal of endotracheal tube post-anesthetic and pain management perform regional blocks documentation of anesthesia note 31 (73.8) 22 (52.4) 40 (95.2) 40 (95.2) 23 (54.8) 22 (52.4%) 39 (92.9%) 17 (40.5%) 39 (92.9%) 165 (62.0) 54 (20.3) 254 (95.5) 243 (91.4) 59 (22.2) 41 (15.4%) 213 (80.1%) 12 (4.5%) 223 (83.8%) χ2 χ2 χ2 χ2 χ2 χ2 χ2 χ2 χ2 2.18 20.08 0.005 0.734 19.71 30.47 3.98 55.01 2.32 0.14 < 0.001 0.94 0.39 < 0.001 < 0.001 0.046 < 0.001 0.13 do you work in an anesthesia practice, where the anesthesiologist supervises the nurse anesthetist? no.(%) yes no 27 (64.3) 15 (35.7) 224 (84.2) 42 (15.8) χ2 9.548 0.002 of the anesthetics you personally administer, how often is an anesthesiologist involved in the following anesthesia activities? mean (sd) pre-anesthetic assessment prescribe anesthetic plan present at induction present for emergencies & urgent situations present for emergence from anesthesia perform post-anesthetic assessment periodically monitor anesthetic course 3.29 (1.81) 3.47 (1.77) 3.50 (1.76) 3.79 (1.65) 3.79 (1.68) 3.33 (1.66) 2.98 (1.69) 3.71 (1.55) 3.87 (1.52) 4.36 (1.22) 4.45 (1.15) 4.49 (1.17) 3.69 (1.39) 3.34 (1.32) t-test t-test t-test** t-test** t-test** t-test t-test** 1.62 1.52 3.05 2.52 2.62 1.51 1.34 0.105 0.129 0.004 0.015 0.012 0.132 0.186 do you work in an anesthesia practice where the surgeons supervise the nurse anesthetist? no. (%) yes no 23 (54.8) 19 (45.2) 125 (47.0) 141 (53.0) χ2 0.877 0.349 of the anesthetics you personally administer, how often is a surgeon involved in the following anesthesia activities? mean (sd) pre-anesthetic assessment prescribe anesthetic plan present at induction present for emergencies or urgent situations present for emergence from anesthesia perform post-anesthetic assessment periodically monitor anesthetic course 2.43 (1.65) 2.45 (1.86) 2.38 (1.83) 2.83 (1.65) 2.19 (1.64) 2.14 (1.72) 2.19 (1.60) 2.08 (1.64) 2.12 (1.70) 2.11 (1.58) 2.80 (1.55) 1.97 (1.40) 1.95 (1.45) 2.09 (1.35) t-test t-test t-test t-test t-test t-test t-test 1.27 1.17 1.00 0.14 0.93 0.76 0.45 0.205 0.241 0.318 0.889 0.354 0.448 0.652 abbreviations: crna, certified registered nurse anesthetist; rna, registered nurse in anesthesia. anesthesia ejournal www.anesthesiaejournal.com volume 6 no.9 2018 page 50 table 5. anesthesia hands-on practice of the participants (n = 308) crnas, no. (%) (n=42) anesthesia dept. nurse, no. (%) (n=152) anesthesia specialty nurse, no. (%) (n=14) recovery room nurse, no. (%) (n=89) operating room nurse, no. (%) (n=11) yes no yes no yes no yes no yes no pre-anesthetic assessment 36 (85.7) 6 (14.3) 95 (62.5) 57 (37.5) 5 (35.7) 9 (64.3) 52 (58.4) 37 (41.6) 8 (72.7) 3 (27.3) prescribe anesthetic plan 25 (59.5) 17 (40.5) 29 (19.1) 123 (80.9) 1 (7.1) 13 (92.9) 20 (22.5) 69 (77.5) 1 (9.1) 10 (90.9) prepare anesthetic material and check anesthesia machine 42 (100.0) 0 (0.0) 146 (96.1) 6 (3.9) 14 (100.0) 0 (0.0) 81 (91.0) 8 (9.0) 11 (100.0) 0 (0.0) inject anesthetic drugs during induction 41 (97.6) 1 (2.4) 140 (92.1) 12 (7.9) 13 (92.6) 1 (7.1) 78 (87.6) 11 (12.4) 11 (100.0) 0 (0.0) insert endotracheal tube and laryngeal mask airway 27 (64.3) 15 (35.7) 34 (20.9) 118 (77.6) 2 (14.3) 12 (85.7) 19 (21.3) 70 (78.7) 0 (0.0) 11 (100.0) manage emergence and decision of removal of endotracheal tube 26 (61.9) 16 (38.1) 22 (14.5) 130 (85.5) 7 (50.0) 7 (50.0) 7 (7.9) 82 (92.1) 1 (9.1) 10 (90.9) post-anesthetic management including pain management 41 (97.6) 1 (2.4) 122 (80.3) 30 (19.7) 10 (71.4) 4 (28.6) 72 (80.9) 17 (19.1) 7 (63.6) 4 (36.4) personally perform regional blocks: spinal, epidural, bier etc 21 (50.0) 21 (50.0) 4 (2.6) 148 (97.4) 0 (0.0) 14 (100.0) 4 (4.5) 85 (95.5) 0 (0.0) 11 (100.0) documentation of anesthesia notes 40 (95.2) 2 (4.8) 139 (91.4) 13 (8.6) 12 (85.7) 2 (14.3) 62 (69.7) 27 (30.3) 9 (81.8) 2 (18.2) summary of key points • in the south korean health care system, rns are an integral part of anesthesia services. these nurses work under different job titles, which may imply that they are not recognized properly as anesthesia providers. • depending on the hospital in which these nurses practice, they may be referred to by a number of different job titles, including anesthesia department nurse, anesthesia specialty nurse, operating room nurse, or even recovery room nurse. regardless of job title, all are involved in providing anesthesia to some degree. • this study revealed that a significant number of both rnas and crnas plan to retire within 5 years. this will likely result in a future shortage of nurse anesthesia providers in the country. • the authors are concerned that the rnas are not required to pass a national certifying examination and that there are no clear standards for their education and scope of practice. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 9 2018 page 51 texas christian university “the science behind the art” volume 10no. 4 2022 anesthesia ejournal online issn 2333-2611 page 1 preoperative optimization of the asthmatic patient ryan jordan, bsn, rn, ccrn affiliation: texas christian university grant/financial support: none biographical data: ryan jordan is a resident registered nurse anesthetist pursuing his dnp in nurse anesthesia at texas christian university in fort worth, texas. keywords: bronchodilators, bronchospasm, asthma, optimization abstract asthma is a common upper respiratory condition among patients across the developmental spectrum estimated to affect over 300 million people worldwide with prevalence rate and condition severity continually increasing.1 the purpose of pursuing this topic is to share a case study to educate anesthesia providers about the complications resulting from intraoperative bronchospasm and to provide guidelines for preventing bronchospasm during the perioperative period. a 77-year-old, female, asa 4, inpatient was undergoing general anesthesia for left percutaneous hip pinning. the patient had significant medical history including asthma and copd (well-controlled) but still experienced bronchospastic events intraoperatively. this case report reviews current prevention, treatment, and optimization of bronchospasm in atrisk adults. aej volume 10no. 4 2022 about the author: ryan jordan is a nurse anesthesia graduate student at texas christian university. ryan received a bs in psychology from the university of georgia in 2012 and a bsn from ut-arlington in 2017. since graduating nursing school, he has worked as a registered nurse in both cardiac and trauma icus at harris methodist fort worth hospital in downtown fort worth, tx. texas christian university “the science behind the art” volume 10 no.4 2022 anesthesia ejournal online issn 2333-2611 page 2 powerpoint template ©2009 texas christian university, center for instructional services. for educational use only. content is the property of the presenter and their resources. introduction • asthma is a common respiratory condition affecting millions of people worldwide • bronchospasms are a defining feature of asthma in which the smooth muscle of the airway contracts and narrows (figure 1)1 • the high prevalence of asthma means that many patients undergoing surgery are at risk of an intraoperative bronchospasm • preventing intraoperative bronchospasm decreases the risk of postoperative respiratory complications • preoperative pharmacologic interventions are a welldocumented method for reducing intraoperative bronchospasm and postoperative respiratory issues. • however, the preventative strategies are often omitted preoperatively for some asthmatic surgical patients • purpose statement: to educate heath care providers about the risks surrounding intraoperative bronchospasm and to encourage the optimization of asthmatic patients prior to surgery. discussion • asthmatic patients undergoing general anesthesia with tracheal intubation are at risk for intraoperative bronchospasm caused by the airway irritation inherent in placement of an endotracheal tube. • intraoperative bronchospasm increases the risk of postoperative pulmonary complications such as prolonged intubation, oxygen desaturation, severe coughing, and postoperative stridor.4 • comprehensive assessment and preoperative pharmacologic optimization of the asthmatic patient is the most effective way of decreasing the incidence of intraoperative bronchospasm and the complications associated with it. • strategies for preventing intraoperative bronchospasm, such as preoperative beta-2 agonist administration, are well documented in the literature • despite the evidence, some patients diagnosed with asthma are not receiving preoperative intervention based on the self-report that their asthma is well-controlled. • if all asthmatic patients, regardless of the severity of their asthma, are pharmacologically optimized during the preoperative period, the overall incidence of intraoperative bronchospasm may be reduced. preoperative optimization of the asthmatic patient ryan jordan, rn, bsn, ccrn, texas christian university clinical assessment well controlled not well controlled poorly controlled symptoms (wheezing, shortness of breath, chest tightness) ≤2 days/week >2 days/week daily night-time awakenings with breathing problems ≤2 x/month 3–4 x/month >1 x/week short-acting beta 2 agonist use for rescue ≤2 days/week >2 days/week but not daily daily interference with normal activity none some limitation extreme limitation exacerbations requiring systemic corticosteroids ≤1 x/year 2–3 x/year >3 x/year patients above 5 years include additionally fev1 predicted >80% 60–80% <60% fev1/fvc >0.8 0.75–0.80 <0.75 table 1. assessment of asthma severity1 abbreviations. fev1, forced expiratory volume in 1 sec; fvc, forced vital capacity. figure 1. asthmatic airway during bronchospasm6 case report • 77-year-old, physical status 4, female presented for closed reduction of left hip and percutaneous pinning. • medical history: copd, well-controlled asthma per patient • due to self-report of well-controlled asthma, no bronchodilator medication were administered. lung sounds clear bilaterally upon auscultation. • preoperative vital signs: bp 154/89 mm hg, hr 82/min, rr 16/min, spo2 98%, oxygen 2 l/min via nasal cannula, temperature 36.5 °c • anesthesia induction: preoxygenation fio2 1.0, 10 l/min, lidocaine 100 mg, fentanyl 100 mcg, propofol 100 mg iv; succinylcholine 100 mg iv for neuromuscular blockade • atraumatic direct laryngoscopy, macintosh #3 blade, size 7.0 mm endotracheal tube, grade 1 cormack-lehane view of vocal cords, positive end-tidal co2 (etco2), bilateral breath sounds equal. • mechanical ventilation, pressure-controlled ventilation with volume guarantee (pcv-vg) mode, rr 12/min, tidal volume (vt) 562ml, fio2 0.5, peak inspiratory pressure (pip) 17 cm h2o, positive end expiratory pressure (peep) 4 cm h2o. • shortly after induction of anesthesia, etco2 decreased, prolonged upstroke on capnogram, spo2 drop from 98% to 91%, pip increase to 38 cm h2o, and breath sounds were absent. • the bronchospasm was quickly treated with multiple 90 mcg puffs of endotracheal albuterol. etco2 returned to 52, spo2 increase to 97%, bilateral breath sounds returned. • the surgical procedure commenced and proceeded without further exacerbation of asthma. • however, prior to emergence, a second severe bronchospasm occurred requiring endotracheal albuterol and epinephrine 100 mcg iv. • the bronchospasm resolved with medications. postoperative course • patient remained intubated, sedated, and was transferred to icu for postsurgical and pulmonary care. the patient was extubated the following day once stable. references 1. bayable sd, melesse dy, lema gf, ahmed sa. perioperative management of patients with asthma during elective surgery: a systematic review. ann med surg. 2021; 70. doi:10.1016/j.amsu.2021.102874 2. dewachter p, mouton-faivre c, emala cw, beloucif s, riou b. case scenario: bronchospasm during anesthetic induction. anesthesiology. 2011; 114(5):1200-1210. doi:10.1097/aln.0b013e3182172cd3 3. maslow ad, regan mm, israel e, darvish a, mehrez m, boughton r, loring sh. inhaled albuterol, but not intravenous lidocaine, protects against intubation-induced bronchoconstriction in asthma. anesthesiology. 2000;93(5):1198–1204. doi:10.1097/00000542-200011000-00011 4. ungern-sternberg bs, sommerfield d, slevin l, drake-brockman tfe, zhang g, hall gl. effect of albuterol premedication vs placebo on the occurrence of respiratory adverse events in children undergoing tonsillectomies: the react randomized clinical trial. jama pediatr. 2019;173(6):527–533. doi:10.1001/jamapediatrics.2019.0788 5. erdoğan t, göksel ö, kırkıl g, et al. is the perioperative period no longer a problem for adult asthmatics under control?-opera study. turk thorac j. 2020;21(3):140-144. doi:10.5152/turkthoracj.2019.18051 6. lynn sj & kushto-reese k. understanding asthma pathophysiology, diagnosis, and management. myamericannurse.com. published july 7, 2015. accessed february 15, 2022. https://www.myamericannurse.com/understanding-asthma-pathophysiology/ 7. bronchospasm 2-patient monitor. kaiser permanente school of anesthesia. youtube.com. published march 2, 2016. accessed february 23, 2022. https://www.youtube.com/watch?v=ty2qb-6gdk4 conclusions & recommendations for practice • every asthmatic patient undergoing surgery with general anesthesia requiring tracheal intubation should be pharmacologically optimized during the preoperative period, regardless of the perceived severity of their asthma. • adopting this practice will likely decrease the incidence of intraoperative bronchospasm and the adverse postoperative complications associated with it. • providing bronchodilatory medications such as albuterol or ipratroprium via inhaler or nebulizer 10 minutes prior to surgery can potentially reduce the costs associated with lengthier hospital stays and increase patient satisfaction scores.1 synthesis of literature • a structured evidence search was conducted to investigate the topic of perioperative asthma optimization • five articles obtained through the search were used as evidence • the design and methods used to investigate the topic varied from a single case study, to prospective randomized control trials, to systematic reviews. • sample sizes used in the studies varied from a small, single participant case study to a large, 484 participant study • the participants included in each sample consisted of surgical patients with history of asthma undergoing general anesthesia with tracheal intubation • measures used in the study focused on the severity of the patients’ asthma and the incidence of adverse perioperative respiratory events (ie, bronchospasm, wheezing, oxygen desaturation) • the results of each study suggest that administration of beta-2 agonists prior to induction of anesthesia greatly reduce the incidence of adverse respiratory events among this patient population • based on the results from these studies, prevention of adverse respiratory events among the asthmatic patient population are largely preventable through preoperative pharmacologic optimization • some of the studies were limited by either sample size or inclusion criteria (such as age or asthma severity) • level of evidence for each of the reviewed studies was assessed using the joanna briggs institute (jbi) levels of evidence • jbi levels included 1a, 1c, 4b, and 4d • future directions for research on prevention of intraoperative bronchospasm should aim at addressing the existing barriers to standardizing the practice of preoperative pharmacologic optimization of the asthmatic patient figure 2. presentation of intraoperative bronchospasm on patient monitor7 classic clinical signs of bronchospasm (eg, tachycardia, decreased spo2, and prolonged upstroke on the capnogram) circled in red assessment • history of asthma should be screened for and assessed during the preoperative period to determine the level of control the patient has over the disease • preoperative assessment of asthma should include: 1) severity of disease (table 1)1 2) triggers (cold air, dust, medications?) 3) frequency of exacerbations 4) effectiveness of treatment (was hospital admission necessary?) 5) steroid use • asthma severity can also be screened for with blood eosinophil counts and pulmonary functions tests volume 7no. 5 2019 educated hand publishing llc “the science behind the art” volume 7 no. 5 2019 anesthesia ejournal online issn 2333-2611 page 15 verification of ventilation before neuromuscular blocker administration during anesthetic induction and endotracheal tube insertion in the non-rapid sequence induction setting abstract anatomically, the upper airway consists of the cartilaginous and bony structures of the nose and mouth, followed by the soft tissue of the oropharynx and laryngopharynx, and ending in the rigid trachea.1 the soft tissue of the pharynx is prone to collapse in the unconscious, or anesthetized, patient and may be further compromised by obesity, a large tongue, airway edema, large neck circumference, external compression, and many other factors.1,4 in response to this collapse, anesthesia professionals who plan to place an endotracheal tube have historically been instructed to refrain from administering muscle relaxation until adequate mask ventilation in the anesthetized patient was confirmed in order to both avoid a critical hypoxemic event, and to ensure an attempt at an escape wake up. however, there is little published evidence to support this practice, and the administration of muscle relaxation before ensuring adequate bvm ventilation remains controversial.1-8 aej skyler murdock, bsn, rn, rrna powerpoint template ©2009 texas christian university, center for instructional services. for educational use only. content is the property of the presenter and their resources. introduction • anesthesia providers who plan to place an endotracheal tube have historically been trained to refrain from administering muscle relaxation until adequate mask ventilation in the anesthetized patient was confirmed in order to both avoid a critical hypoxemic event, and to ensure an attempt at an escape wake up. • mask ventilation is an important skill and can be lifesaving in cases of difficult intubation. • just as positioning maneuvers, chin lifts, or airway devices can help overcome collapsed pharyngeal tissue, knowing when to administer an nmb can make the difference between a failed and a successful oxygenation attempt. • there is little published evidence to support the practice of ensuring adequate mask ventilation before nmb adminstration.1-8 conclusion • no anesthetic airway plan is assured to work every time, but a review of available evidence demonstrates that nmb administration is often part of the solution to a difficult bvm oxygenation attempt.4,6 • the immediate goal after delivering a non-rsi anesthetic induction should be to optimize oxygenation.4 optimization of oxygenation may include the use of bvm, endotracheal tube or laryngeal mask placement; all of which have been demonstrated to be made easier by nmb administration.4 • if verification of ventilation before nmb administration was essential to patient safety, then all patients needing a rapid sequence induction would require an awake fiberoptic intubation.6 • the difficult airway algorithm advises that an airway exam should be performed in all patients.13 this alone is one of the best indicators of a difficult airway, and along with any history of a difficult airway, should serve as the basis for selection of induction and airway management technique. verification of ventilation prior to neuromuscular blocker administration during anesthetic induction case summary • a 67-year-old, 125 kg, 1.78 m, male presented adequately fasted for robotic prostatectomy. • the patient’s medical history included prostate cancer, hypertension, obesity (with a bmi of 39.5), chronic obstructive pulmonary disease (copd), current smoker with a 28-pack year smoking history, obstructive sleep apnea (osa), diabetes mellitus type 2, using a cpap machine at night with a 2l oxygen (o2) bleed in, 2 pillow orthopnea, and dyspnea on exertion with ~ 5 measure of exercise tolerance (mets). • mallampati class 3, 2 fingers breadth thyromental distance (tmd), upper lip bite test class ii, large and short neck, and decreased lung sounds. the patient was unable to lay supine and required 2l nasal cannula. • following anesthetic induction with fentanyl 100 mcg iv, lidocaine 100 mg iv, and propofol 200 mg iv., the initial bag valve mask (bvm) attempt in ramp position was unsuccessful. oral airway insertion, apl adjustment, and two provider bvm ventilation resulted in a tidal volume of 100 ml and a spo2 of 88%. • succinylcholine 200 mg was then administered and two provider bvm continued. after 30 seconds, the patient’s tidal volume increased to 350 ml and the oxygen saturation returned to 98%. references 1. saddawi-konefka ds, hung sl, kacmarek rm, jiang, y. optimizing mask ventilation: literature review and development of a conceptual framework. respiratory care. 2015;60(12):1834-1840. 2. joffe am, ramaiah r, donahue e, galgon re, thilen sr, spiekerman cf, bhananker sm. ventilation by mask before and after the administration of neuromuscular blockade: a pragmatic non-inferiority trial. bmc anesthesiol. 2015;15:134. pmid 26444853. 3. broomhead rh, marks rj, ayton mp. confirmations of the ability to ventilate by facemask before administration of neuromuscular blocker: a non-instrumental piece of information? british journal of anaesthesia. 2010;104(3):313-317 4. patel a. facemask ventilation before or after neuromuscular blocking drugs: where are we now? anaesthesia. 2014;69:801-815. 5. warters rd, szabo ta, spinale fg, desantis sm, reves jg. the effect of neuromuscular blockade on mask ventilation. anaesthesia. 2011;66:163-167. 6. priebe h. ventilation before paralysis. anesthesiology. 2013;4(118):992-993. 7. patel a, pearce a. progress in management of the obstructed airway. anaesthesia 2011;66:93-100. 8. calder i, yentis sm. could ‘safe practice’ be compromising safe practice? should anaesthetists have to demonstrate that face mask ventilation is possible before giving a neuromuscular blocker? anaesthesia. 2008; 63:113-5 9. frerk c, pearce a. induction and maintenance of anaesthesia. in: cook t, woodall n, frerk c, eds. 4th national audit project of the royal college of anaesthetists and the difficult airway society. major complications of airway management in the united kingdom. london: rcoa, 2011: 55–61. 10. 10. thomas bf, parks lj. propofol. statpearls. 2018. https://www.ncbi.nlm.nih.gov/books/nbk430884/ 11. jense hg, dubin sa, silverstein pi, o’leary-escolas u. effect of obesity on safe duration of apnoea in anesthetized humans. anesth analg 1991; 72: 89–93 12. wittekamp bh, vanmook wn, tjan dh, zwaveling jh, bergmans dc. clinical review: post-extubation laryngeal edema and extubation failure in critically ill adult paitents. crit care. 2009;13(6):233. 13. apfelbaum, jl, hagberg ca, caplan ra, blitt cd, et al. practice guidelines for management of the difficult airway: an updated report by the american society of anesthesiologists task force on management of difficult airway. anesthesiology. 2013;118:251270. 14. kpman af, zhaku b, lai ks. the “intubating dose” of succinylcholine: the effect of decreasing doses on recovery time. anesthesiology. 2003;99(5):1050-1054. 15. pseudocholinesterase deficiency. u.s. national library of medicine. genetic home reference. https://ghr.nlm.nih.gov/condition/pseudocholinesterase-deficiency#statistics 16. naguib m, brewer l, lapierre c, kopman af, johnson kb. the myth of rescue reversal in “can’t intubate, can’t ventilate” scenarios. anesth analg. 2016;123(1):82-92. 17. mevorach dl. the management and treatment of recurrent postoperative laryngospasm. anaesth analg 1996;83:1110-1111. recommendations • administering an nmb during induction, with the proper reversal agent readily available, should not theoretically alter an escape wake up plan. • while assessing bag mask ventilation prior to administering a neuromuscular blocker may provide information relevant to the entire perioperative airway management event, additional research is needed to further delineate in exactly which situations it is most appropriate to assess ventilation versus proceeding immediately with neuromuscular blockade. paralytics and suggamadex •testing bvm adequacy before nmb administration may aid the anesthesia provider in deciding which nmb agent to use for an intubation attempt if suggamadex is not readily available. •even though no publications exist to support this type of scenario, it is possible that nmb administration will not improve bvm attempts and create a much more serious situation of cannot intubate cannot ventilate. •succinylcholine has a duration of action similar to propofol, of 5-10 minutes depending on the dose used.10, 14, 16 • succinylcholine is metabolized by pseudocholinesterase, and it is estimated that an atypical pseudocholinesterase phenotype may occur as often as 1 in 480 (heterozygous phenotype) to 1 in 3,200 (homozygous phenotype) people.15 • an unknown atypical phenotype may result in a can’t intubate can’t ventilate (cicv) scenario in a patient who does not have the ability to recover from the paralytic before a hypoxic event occurs. •suggamadex 16 mg/kg reliably reverses the paralytic effect of a 1.2 mg/kg dose of rocuronium in about 4.5 minutes, faster than the typical offset of the neuromuscular blocking effects of a standard dose of succinylcholine.16 • while suggamadex will rapidly and reliably reverse the effects or rocuronium or vecuronium, the choice and timing of anesthetic induction agent may preclude return of adequate spontaneous ventilation.16 • neuromuscular reversal in the setting of a collapsed airway may result in negative pressure pulmonary edema, and worsen patient outcomes.16 difficult airway algorithm •the algorithm does not address the timing of nmb administration. •in a case of difficult bvm, excessive bvm ventilation attempts, which may occur while following the difficult airway algorithm, may waste valuable functional residual capacity (frc) or result in increased intragastric pressure predisposing the patient to an aspiration event. • early nmb administration has potential to prevent increases in intragastric pressure and may preserve frc for an intubation attempt. •incidence of laryngospasm is 0.78-5%. 17 • administering an nmb medication from the start of induction would rule out a potential laryngospasm and may allow faster diagnoses of other airway complications in a more timely manner. professional opinion •when given an emergency scenario of a difficult bvm attempt, 89% of survey respondents reported that they would administer a nmb in order to improve ventilation efforts.3 • anesthesia professionals who verify ventilation before administering a nmb are establishing relevant, but not instrumental, anesthetic induction information.3 • use of this relevant, but not instrumental, information may have benefit postoperatively. • may provide evidence of the support needed after a deep extubation, or during recovery in the post anesthesia care unit. • however, post intubation laryngeal edema may occur in up to 30% of patients, resulting in a postsurgical airway that is different from the presurgical airway.12 •national audit project of the royal college of aneasthetists and the difficult airway society: • “where facemask or laryngeal mask anaesthesia is complicated by failed ventilation and increasing hypoxia the anaesthetist should consider early administration of further anaesthetic agent and/or a muscle relaxant to exclude and treat laryngospasm…..no anaesthetist should allow airway obstruction and hypoxia to develop to the stage where an emergency surgical airway is necessary without having administered a muscle relaxant.” 9 controlled trial •ventilation was performed 30 seconds after the patient became nonresponsive to eyelash stimulation.5 a non-blinded anesthesia professional then administered either rocuronium 0.6 mg/kg or 0.9% saline, and repeat ventilation was performed 2 minutes later.5 • bvm ventilation scores were significantly better in the group that received rocuronium.5 • amongst patients who had initially difficult bvm ventilation scores, the improvement in bvm ventilation was even more pronounced.5 propofol •anesthetic induction dose of propofol will have respiratory depression effects that last 8-11 minutes.10, 16 • adequate preoxygenation in patients of normal weight resulted in a < 90% spo2 desaturation time of 6.06 minutes, and obese patients desaturated in 2.72 minutes.11 • as such, the likelihood of returning to adequate spontaneous ventilation before a decrease in spo2, in a patient under the influence of an induction dose of propofol, is small.1,4,6 anesthesia ejournal www.anesthesiaejournal.com volume 7 no.5 2019 page 16 skyler murdock, bsn, rn, rrna volume 8no. 9 2020 educated hand publishing llc “the science behind the art” volume 8 no. 9 2020 anesthesia ejournal online issn 2333-2611 page 27 rocuronium vs succinylcholine: emergency airway management of the covid-19 patient ryan shores, dnp, crna* katherine fowler, dnp, crna* john mcdonough, edd, dr. (habil) nsa, crna, aprn* amy suralis, dnp, crna* denise schindele, ba, ccrn, rna*^ tilmann müller-wolff, ma, bsc, rna, ccrn*^ affiliation: *university of north florida ^klinikum ludwigsburg, germany funding/conflict of interest disclosure: none keywords: covid-19, airway management; rapid sequence induction; rocuronium; succinylcholine abstract severe acute respiratory syndrome-coronavirus-2 (sars cov-2) infection leading to the covid-19 pandemic has created a new paradigm and challenge for airway management. anesthesia providers perform tracheal intubation in a variety of settings where the best possible approach and plan for tracheal intubation is determined including patient anatomy, pathophysiology and urgency. sars cov-2 is a highly contagious rna virus that has caused widespread infections, severe respiratory disease, and deaths. the purpose of this article is to describe current international standards of covid-19 airway management, review the multi-system pathophysiology of covid-19 patients, as well as evidence-based pharmacologic options available for intubating covid-19 patients. this review supports rapid sequence induction with minimal airway manipulation using rocuronium 1.2-1.5 mg/kg with an option of sugammadex (16 mg/kg) reversal as a safer and superior choice to succinylcholine. aej introduction severe acute respiratory syndrome-coronavirus-2 (sars cov-2) infection leading to the covid-19 pandemic has created a new paradigm and challenge for airway management. anesthesia providers perform tracheal intubation routinely in a variety of settings where the best possible approach and plan for tracheal intubation is determined including patient anatomy, pathophysiology and urgency. sars cov-2 is a highly contagious rna virus that has caused widespread infections, severe respiratory disease, and deaths.1 a study conducted in lombardy, italy revealed that 88% of covid-19 patients who were critically ill needed mechanical ventilation.14 in italy, march 2020 up to 15% of all covid-19 infected individuals were active healthcare staff.4 alternative and safer airway management techniques must be used. in order to protect and prevent more healthcare providers from becoming infected with covid patients needing airway management have been preferentially intubated, initiating full ventilator support and then placed in the prone position for twelve hours per day to improve oxygenation and alveolar recruitment.4-6 the american association of nurse anesthetists (aana), american society of anesthesiologists (asa), and anesthesia patient safety foundation (apsf) suggest using rapid sequence induction (rsi) for endotracheal intubation in covid-19 patients.7, 8 the rsi technique for covid-19 patients includes a sedative-hypnotic and rapid-acting muscle relaxant. some practitioners recommend the use of ketamine 1-2 mg/kg to enhance bronchodilation.7 muscle relaxation during rsi can be achieved with succinylcholine or rocuronium. choice of drug for muscle relaxation during rsi is multifactorial in covid patients. obviously a drug with a rapid onset is desired after full preoxygenation and denitrogination.7,8 the other primary consideration is the ability to reverse and/or recover from muscle relaxation in the event tracheal intubation is unsuccessful. succinylcholine is rapidly metabolized by plasma pseudocholinesterase and does not need a reversal agent.9 rocuronium has a longer duration of action. without reversal, an rsi intubating dose (1.2 mg/kg) would result in extended paralysis.10 the reversal agent sugammadex, specific for rocuronium and vecuronium, can provide rapid recovery of muscle relaxation even with larger doses of rocuronium.11 this article will discuss existing evidence supporting the merits of a pharmacologic plan utilizing rocuronium with sugammadex reversal in lieu of succinylcholine when providing endotracheal intubation in the covid-19 patient population. review of literature cinahl, pubmed, and cochrane database of systematic reviews were searched using key words, rapid sequence induction, covid, sars-cov-2, rocuronium, succinylcholine, sugammadex, and airway management. inclusion criteria included prospective and retrospective articles that evaluated rocuronium and succinylcholine for onset times and/or recovery. additional relevant literature included recent data analyses, monographs, case analyses, and guidelines specific to covid. sars-cov-2 pathophysiology and respiratory compromise sars cov-2 emerged in press headlines december 2019 due to the aggressive pneumonia outbreak in wuhan, china.1 this pneumonia progressed to severe adult respiratory distress syndrome (ards) and was highly communicable. by march 11, 2020 the virus had spread to over 100 countries. the world health organization (who) declared sars cov-2 a pandemic and named the disease covid-19.1 the sars-cov-2 virus is known for causing severe acute respiratory symptoms (eg, dry cough, dyspnea, adult respiratory distress syndrome (ards).12 the virus gains access into the host through angiotensin converting enzyme 2 (ace2) receptors in the pulmonary epithelium.13 once sars-cov-2 enters the alveolar epithelium, it elicits an intense inflammatory response that can lead to pneumonia, and in many cases ards. there are several host factors that make certain people more susceptible to a severe form of the disease. these include increased age, and comorbidities such as hypertension, chronic kidney disease, cardiovascular disease, and diabetes.13–15 one of the unique factors of sars-cov-2 is that it has a long incubation period, up to 14 days.12 most people start with symptoms of dry cough, malaise, and fever. 12,16 dyspnea usually develops days after first symptoms emerge, and progresses to pneumonia and ards quickly thereafter.17 sars-cov-2 can affect other organ systems as well. one of the most common complications is acute renal insufficiency, in as many as 20-30% of patients with severe sars-cov-2.15,17 the cause of this is multifactorial, including cytotoxic effects of viral accumulation in the renal tissue after entrance in circulation, possibly through renal ace2 receptors, deposits of inflammatory mediators in the kidney, and end-organ effects of hypoxia, shock, and rhabdomyolysis.13 in a study by cheng et al, 15% of patients admitted to the hospital diagnosed with covid-19 had new elevated baseline serum creatinine level ranging up to 359 micromoles/liter. the authors concluded that the mortality for all patients with covid-19 was 12.5% but those with elevated serum creatinine increased to 30.9% .13 pharmacology of muscle relaxants and reversal because of increased likelihood of acute renal injury in this population, succinylcholine should be avoided as part of rsi and endotracheal intubation.18 rapid sequence induction can be accomplished with the use of high dose rocuronium (1.2 to 1.5 mg/kg). succinylcholine is a depolarizing skeletal muscle relaxant that has been used by anesthesia providers since 1952 for endotracheal intubation.9 it binds, as an agonist, to nicotinic receptors at the neuromuscular junction resulting in temporary flaccidity of striated muscles. it is rapidly hydrolyzed by plasma pseudocholinesterase into succinylmonocholine, within 4-6 minutes. this time can be extended by drug-drug interactions, or if the patient has a deficiency in pseudocholinesterase. the likelihood of this deficiency is low (1:2500).9 it is also well-known that succinylcholine can produce acute lethal hyperkalemia leading to ventricular tachycardia and fibrillation in certain populations (eg, active infection, paralysis, or immobility) and is a trigger for malignant hyperthermia leading to death if untreated.9 as many covid patients suffer from acute renal injury, lethal hyperkalemia could be possible. educated hand publishing llc “the science behind the art” volume 8 no. 9 2020 anesthesia ejournal online issn 2333-2611 page 28 educated hand publishing llc “the science behind the art” volume 8 no. 9 2020 anesthesia ejournal online issn 2333-2611 page 29 rocuronium, an aminosteroidal nondepolarizing neuromuscular blocking agent, is another choice commonly used by anesthesia providers for endotracheal intubation. it antagonistically attaches to nicotinic receptors, preventing acetylcholine binding, thereby preventing muscle cell depolarization.10 rocuronium is primarily metabolized in the liver and undergoes biliary excretion. rocuronium does not have the precautions or contraindications that are unique to succinylcholine. the recommended dose producing standard intubating conditions is 0.6 mg/kg, however intubating conditions have been reported as suboptimal and unpredictable.10 administration of 1.2 mg/kg of rocuronium is recommended for optimal rsi intubating conditions however muscle relaxation can exceed 60 minutes .10 reversal with an anticholinesterase such as neostigmine would be ineffective at this higher dose, but could be achieved with sugammadex. sugammadex is a modified gamma cyclodextrin. it binds to rocuronium and to a lesser degree vecuronium, to form a complex that can no longer actively bind to nicotinic receptors. the complex molecule is excreted unchanged in the urine without affecting acetylcholine concentrations. a sufficient dose of sugammadex (16 mg/kg to reverse a rocuronium dose of 1.2 mg/ kg) delivers a sufficient and complete reversal.11 sugammadex: rocuronium binding is 1:1, so dosing in the presence of covid would be unaffected.11 covid-19 intubation pharmacologic plan current literature supports rapid sequence induction with minimal or no manual positive pressure ventilation is preferred over standard induction techniques.7which causes coronavirus disease 2019 (covid-19,8 the choice of muscle relaxant during rsi is primarily determined by a need for a rapid onset of quality intubating conditions. a recent 2015 cochrane systematic review comparing succinylcholine to rocuronium determined that rocuronium was “slightly less effective than succinylcholine for creating excellent and acceptable intubation conditions.”20 most studies included in the systematic review compared succinylcholine to a rocuronium dose closer to the standard intubating dose of 0.6mg/kg. however, sugammadex provided rapid and complete reversal of even higher doses of 1.2 mg/kg.11 more recent studies have indicated no significant differences in time to intubation, vocal cord movement, or patient movement when rocuronium doses of 1.2 mg/kg are utilized.21-24 evidence suggests that a rocuronium-sugammadex combination would also improve recovery time compared to succinylcholine alone. a 2010 systematic review found significant improvement in recovery time using rocuronium-sugammadex compared to succinylcholine (p<0.0001) (see figure 1).26 another study examining 110 adults ages 18-65 undergoing general anesthesia, compared succinylcholine 1 mg/kg to rocuronium 1.2 mg/kg from induction administration to full recovery when sugammadex was utilized for reversal. individuals in the rocuronium group were given sugammadex 16 mg/kg three minutes after rocuronium administration. end point measures were a t4 of 10% and 90% of the t1 on a train of four measurement with accelerometry. succinylcholine mean recovery times were 7.1 and 10.9 minutes. the rocuronium/sugammadex group was 4.4 and 6.2 minutes. it was important to note that the study included a three minute wait before administering sugammadex, which indicated that recovery endpoints were reached at an average of 1.4 and 3.2 minutes once sugammadex was administered.23 another randomized, controlled, double-blinded study compared succinylcholine 1 mg/kg to rocuronium 1 mg/kg in 61 adults ages 18-60 requiring rapid sequence induction. patients were given rocuronium, then sugammadex 16 mg/kg was administered as soon as tracheal intubation was achieved. primary measures were duration from tracheal intubation to return of spontaneous ventilation and t4 return of 90% of t1. average time for the succinylcholine group was 406 seconds for return of spontaneous ventilation and 518 seconds for t1=90%. average time for the rocuronium/sugammadex group was 216 seconds for return of spontaneous ventilation and 168 seconds respectively. it is important to note that when comparing the time from muscle relaxant administration to t1=90%, the mean times were 719 seconds for the succinylcholine group and 282 seconds for the rocuronium/sugammadex group.24 figure 1. time (seconds) from administration of succinylcholine or rocuronium/sugammadex to 90% recovery of t1 on a train of four (tof) note: time from administration of rocuronium to administration of sugammadex was 180 seconds in study 1 and 114 seconds in study 2 conclusion this literature review suggests that patients with sars-cov-2 could benefit from a pharmacologic intubation plan that includes rsi using rocuronium 1.2 mg/kg with sugammadex 16 mg/ kg. current literature is limited by small sample sizes and lack of high-quality studies.  other considerations include the availability of sugammadex and provider comfort with these agents.  in some cases, patients emergently intubated are done so by non-anesthesia personnel with limited knowledge of both the pharmacologic implications of commonly used medications and disease process of sars-cov-2. the evidence in this review should be considered when determining implications of the pharmacologic plan on outcome of intubating patients with sars-cov-2.  educated hand publishing llc “the science behind the art” volume 8 no. 9 2020 anesthesia ejournal online issn 2333-2611 page 30 references 1. wang w, xu y, gao r, et al. detection of sars-cov-2 in different types of clinical specimens. jama. 2020;323(18):18431844. doi:10.1001/jama.2020.3786 2. westhoff m, schönhofer b, neumann p, et al. noninvasive mechanical ventilation in acute respiratory failure. pneumologie. 2015;69(12):719-756. 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https://www.accessdata.fda.gov/drugsatfda_docs/label/2015/022225lbl.pdf. updated february 1, 2015. accessed april 13, 2020. 12. park se. epidemiology, virology, and clinical features of severe acute respiratory syndrome -coronavirus-2 (sars-cov-2; coronavirus disease-19). clin exp pediatr. 2020;63(4):119-124. doi:10.3345/cep.2020.00493 13. cheng y, luo r, wang k, et al. kidney impairment is associated with in-hospital death of covid-19 patients. medrxiv. https://doi.org/10.1101/2020.02.18.20023242. updated february 20, 2020. accessed march 2, 2020. 14. grasselli g, zangrillo a, zanella a, et al. baseline characteristics and outcomes of 1591 patients infected with sars-cov-2 admitted to icus of the lombardy region, italy. jama. 2020;323(16):1574-1581. doi:10.1001/jama.2020.5394 15. disease ek, palevsky apm, radhakrishnan j, townsend rr. coronavirus disease 2019 (covid-19 ): issues related to kidney disease and hypertension. https://www.uptodate.com/contents/coronavirus-disease-2019-covid-19-issues-related-tokidney-disease-and-hypertension. updated june 16, 2020. accessed march 3, 2020. 16. centers for disease control and prevention. symptoms of coronavirus. cdc. https://www.cdc.gov/coronavirus/2019-ncov/ symptoms-testing/symptoms.html. updated february 8, 2020. accessed april 12, 2020. 17. anesi gl. coronavirus disease 2019 (covid-19): critical care and airway management issues. uptodate. https:// www.uptodate.com/contents/coronavirus-disease-2019-covid-19-critical-care-issues/print?search=neumonía en el embarazo&source=search_result&selectedtitle=2~150&usage_type=default&display_rank=2. updated february 1, 2020. accessed march 28, 2020. 18. london amj. coronavirus disease 2019 (covid-19): anesthetic concerns, including airway management and infection control. https://www.uptodate.com/contents/coronavirus-disease-2019-covid-19-patients-airway-management-anesthesiamachine-ventilation-and-anesthetic-care/print?search=coronavirus&source=search_result&selectedtitle=7~150&usage_ type=default&display_rank=7. updated february 1, 2020. accessed april 12, 2020. 19. martyn jaj, richtsfeld m. succinylcholine-induced hyperkalemia in acquired pathologic states. anesthesiology. 2006;104(1):158-169. doi:10.1097/00000542-200601000-00022 20. dtt t, ek n, vah m, js l, ga w, jj p. rocuronium versus succinylcholine for rapid sequence induction intubation. cochrane database syst rev. 2015;2015(10):cd002788. doi:10.1002/14651858.cd002788.pub3.copyright https://www.asahq.org/in-the-spotlight/coronavirus-covid-19-information/caesar. https://www.accessdata.fda.gov/drugsatfda_docs/label/2010/008453s027lbl.pdf https://www.accessdata.fda.gov/drugsatfda_docs/label/2010/008453s027lbl.pdf http://www.accessdata.fda.gov/drugsatfda_docs/label/2008/078717s000lbl.pdf. http://www.accessdata.fda.gov/drugsatfda_docs/label/2008/078717s000lbl.pdf. https://www.accessdata.fda.gov/drugsatfda_docs/label/2015/022225lbl.pdf. https://doi.org/10.1101/2020.02.18.20023242 https://www.uptodate.com/contents/coronavirus-disease-2019-covid-19-issues-related-to-kidney-disease-and-hypertension https://www.uptodate.com/contents/coronavirus-disease-2019-covid-19-issues-related-to-kidney-disease-and-hypertension https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/symptoms.html https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/symptoms.html https://www.uptodate.com/contents/coronavirus-disease-2019-covid-19-critical-care-issues/print?search=neumonía en el embarazo&source=search_result&selectedtitle=2~150&usage_type=default&display_rank=2 https://www.uptodate.com/contents/coronavirus-disease-2019-covid-19-critical-care-issues/print?search=neumonía en el embarazo&source=search_result&selectedtitle=2~150&usage_type=default&display_rank=2 https://www.uptodate.com/contents/coronavirus-disease-2019-covid-19-critical-care-issues/print?search=neumonía en el embarazo&source=search_result&selectedtitle=2~150&usage_type=default&display_rank=2 https://www.uptodate.com/contents/coronavirus-disease-2019-covid-19-patients-airway-management-anesthesia-machine-ventilation-and-anesthetic-care/print?search=coronavirus&source=search_result&selectedtitle=7~150&usage_type=default&display_rank=7. https://www.uptodate.com/contents/coronavirus-disease-2019-covid-19-patients-airway-management-anesthesia-machine-ventilation-and-anesthetic-care/print?search=coronavirus&source=search_result&selectedtitle=7~150&usage_type=default&display_rank=7. https://www.uptodate.com/contents/coronavirus-disease-2019-covid-19-patients-airway-management-anesthesia-machine-ventilation-and-anesthetic-care/print?search=coronavirus&source=search_result&selectedtitle=7~150&usage_type=default&display_rank=7. 21. patanwala ae, stahle sa, sakles jc, erstad bl. comparison of succinylcholine and rocuronium for first-attempt intubation success in the emergency department. acad emerg med. 2011;18(1):10-14. doi:10.1111/j.1553-2712.2010.00954.x 22. perša l, kamenik m, nevenka, škvarč k, mekiš d. rocuronium versus succinylcholine for rapid sequence intubation in patients with bowel obstruction. signa vitae. 2019;15(2):52-58. doi:10.22514/sv152.102019.8 23. lee c, jahr js, candiotti ka, warriner b, zornow mh, naguib m. reversal of profound neuromuscular block by sugammadex administered three minutes after rocuronium: a comparison with spontaneous recovery from succinylcholine. anesthesiology. 2009;110(5):1020-1025. doi:10.1097/aln.0b013e31819dabb0 24. sørensen mk, bretlau c, gätke mr, sørensen am, rasmussen ls. rapid sequence induction and intubation with rocuronium-sugammadex compared with succinylcholine: a randomized trial. br j anaesth. 2012;108(4):682-689. doi:10.1093/bja/aer503 25. malhotra s. practice guidelines for management of the difficult airway. pract guidel anesth. 2016;(2):127-127. doi:10.5005/ jp/books/12644_18 26. chambers d, paulden m, paton f, et al. sugammadex for reversal of neuromuscular block after rapid sequence intubation: a systematic review and economic assessment. br j anaesth. 2010;105(5):568-575. doi:10.1093/bja/aeq270 educated hand publishing llc “the science behind the art” volume 8 no. 9 2020 anesthesia ejournal online issn 2333-2611 page 31 texas christian university “ the science behind the art” volume 12 no.1 2024 anesthesia ejournal online issn 2333-2611 page 1 congenital long qt syndrome: a cardiac ion channelopathy with important anesthetic considerations david e. harris, phd, rn affiliation: university of new england school of nurse anesthesia grant/financial support: none keywords: long qt syndrome, cardiac ion channel, channelopathy abstract congenital long qt syndrome (clqts) is the most common genetic cardiac ion channelopathy in the us. patients with clqts are at risk for ventricular tachycardia (vt) in the “torsades de pointes” (tdp) pattern from physical and emotional stress, including during the perioperative period. this narrative review outlines the history and pathophysiology of the most common types of clqts, describes treatments for clqts, discusses the experience of anesthesia providers with clqts, and reports recommendations for safe administration of anesthesia to these patients. no definitive guidelines exist for the anesthetic management of patients with clqts, therefore the anesthesia provider must rely on existing evidence to choose a safe anesthetic for this challenging patient population. aej volume 12no. 1 2024 introduction congenital cardiac ion channelopathies are familial syndromes caused by mutations in the genes coding for cardiac ion channel proteins.1 congenital long qt syndrome (clqts) is the most common congenital cardiac ion channelopathy in the us.2 it is present in apparently healthy patients with structurally normal hearts and can cause premature ventricular contractions (pvcs), initiating ventricular tachycardia (vt) in the “torsades de pointes” (tdp) pattern in which the qrs complex “twists” around the isoelectric line of the ecg. tdp can lead to ventricular fibrillation (vf) and sudden arrhythmic cardiac death (scd).3 the ventricular ectopy of clqts can be triggered by adrenergic stimulation, including from physical and emotional stress1, or during the perioperative period.4 the likelihood of an anesthesia provider encountering a patient with lqts may be increased due to: 1) some patients (including young children) with clqts benefit from implantable cardioverter defibrillators (icds)5 or cardiac sympathetic denervation6,7 and will need anesthesia for the device insertion or surgery8,9, and 2) people with one subtype of clqts (lqt1) are often born with congenital sensorineural deafness10 and may present for cochlear implants.11 this paper is a narrative literature review of clqts focusing on the anesthesia implications of the most common types (lqt1 through 3). clqts is of interest to anesthesia providers because patients with clqts may require anesthesia for any reason and for issues related to clqts, and because clqts can produce sudden cardiac death in the perioperative period. the goals of paper of this paper are to: • review the history and pathophysiology of clqts, • describe common treatments for clqts, • discuss the experience of anesthesia providers with patients with clqts, and • report recommendations for safe administration of anesthesia to these patients. methods searches of medline (pubmed) and google scholar were conducted using the terms “congenital long qt syndrome”, “lqts”, and “cardiac ion channelopathy” combined with “surgery” and “anesthesia”. further relevant articles were identified from the bibliographies of these sources. a total of 215 articles were reviewed and 49 selected for inclusion based on relevance, scope, and unique information. results history of clqts: clqts was first described in 1957 when jervell and lange-neilsen reported a family in which 4 of 6 children had congenital deafness and “fainting spells”. two of the children with fainting spells had prolonged qt intervals and three died suddenly but had no structural cardiac defects on autopsy.12 in 1964, ecg and genogram analysis of children in “schools for the deaf ” showed that the syndrome of congenital deafness, prolonged qt interval, and high risk of sudden cardiac death was inherited in an autosomal recessive pattern.13 another family with a history of sudden cardiac death across multiple generations and 3 siblings who had syncopal attacks, prolonged qt intervals, but normal hearing was described by romano in 1965. the normal hearing and multi-generational presentation in this family suggested a distinct autosomal dominant form of clqts.14 there are 17 known subtypes of clqts (lqt1 – lqt17).3,15 the genes responsible for the most common types of clqts (lqt1 – lqt3) were identified in the 1990s. in 1995 a gene (kcnh2) coding for the cardiac voltage-gated potassium channel which produces the rapid potassium repolarization current (ikr) was found responsible for lqt216 and a gene (scn5a) coding for cardiac voltage-gated sodium channel responsible for the depolarization current (ina) was found responsible for lqt3.17 a gene (kcnq1) for the voltage-gated potassium channel producing the slow potassium repolarization current (iks) was determined responsible for lqt1 in 1997.18 subsequently, the genes responsible for rarer types of clqts have been identified.3,15,19,20,21,22 clqts in the general population: the prevalence of clqts is 1/2000 live births.23 patients with clqts are often identified via genetic testing when a family member is diagnosed. they are also diagnosed after episodes of syncope, palpitations, or even after surviving sudden cardiac arrest.2 if symptomatic, people with clqts are usually diagnosed as children, but they may be asymptomatic and undiagnosed well into adulthood.24 thus, patients with both diagnosed and undiagnosed clqts present for anesthesia. the triggers for tdp differ by clqts subtype. for patients with lqt1, adolescent and preadolescent males are at greatest risk for tdp, which is often triggered by exercise, including swimming. in lqt2, adult female patients are most at risk for tdp, particularly in the postpartum period and when exposed to sudden alarming auditory stimuli. for lqt3, adult males are at greatest risk and tdp commonly occurs during rest or sleep.3,25 as many as one in five untreated patients with symptomatic clqts die within a year but the mortality rate falls to 1% over 15 years with appropriate therapy.2 electrophysiology of clqts: the action potential in ventricular cardiac muscle is divided into phases. beginning at a resting membrane potential of ~ -96 mv, phase 0 is a rapid depolarization to ~ +20 mv caused by the opening of voltage-gated na+ channels. during phase 1 there is a slight repolarization as na+ channels close. this repolarization is interrupted by the opening of slow, long acting, voltage-gated (l-type) ca++ channels. this produces phase 2, a prolonged plateau at ~ +10 mv during which the depolarizing calcium current is balanced by the repolarizing rapid and slow potassium currents (ikr and iks). next the l-type ca++ channels close and current flow through k+ channels increases. this causes a rapid repolarization (phase 3) that reestablishes the resting membrane potential (phase 4).1,25,26 on the ecg, the qt interval is measured from the beginning of the qrs complex (ventricular depolarization) to the end of the t wave (ventricular reoperation).26 however, because depolarization and repolarization are brief events, most of the qt interval reflects the plateau of phase 2.1 any channelopathy that prolongs the plateau will lengthen the qt interval. lqt1, 2, and 3 account for 75 to 85% of clqts cases.2,27 the remaining variants (lqt4 – lqt17) are each responsible for ≤1% of cases.28 lqt1 and lqt2 are caused by loss of function texas christian university “ the science behind the art” volume 12 no.1 2024 anesthesia ejournal online issn 2333-2611 page 2 mutations to genes (kcnq1 and kcnh2) coding for the k+ channels responsible for the iks and ikr currents that cause cardiac repolarization. these mutations delay repolarization. lqt3 is caused a gain of function mutation in the gene (scn5a) coding for the na+ channel responsible for the depolarizing ina current. this mutation delays inactivation of the channel. all three prolong phase 2 of the cardiac action potential and the qt interval.15,27 voltage gated ion channels, including the l-type ca++ channel, generally enter a refractory period after closing. normally, by the time the l-type ca++ channel leaves its refractory state the cardiac myocyte membrane has repolarized and the channel is not reactivated. however, in patients with clqts, the l-type ca++ channels of some cardiac myocytes leave their refractory period before the end of the prolonged plateau phase when the membrane is still depolarized. the l-type ca++ channels are reactivated in a process known as an “early afterdepolarization” and cause a premature ventricular contraction (pvc).1,2,27 because different areas of the ventricular myocardium repolarize at different rates, a single pvc can give rise to vt via a reentry mechanism. this vt takes the form of tdp as the depolarization pathway circling the ventricle changes.2,28 sympathetic stimulation, with its tachycardia, put patients with clqts, particularly those with lqt1 and 2, at risk for tdp. in the normal heart, sympathetic stimulation activates potassium channels responsible for the iks current and repolarization so that the duration of the cardiac action potential, and the qt interval, shorten as the heart rate increases and the rr interval decreases. (the rr interval is the time, in seconds, between consecutive r waves.) this allows the myocardium to repolarize fully before the next normal depolarization occurs. however, in lqt1 the channel responsible for iks does not respond to sympathetic stimulation, the qt interval is not shortened as heart rate increases, parts of the myocardium remain depolarized, and l-type calcium channels can cause early afterdepolarizations giving rise to tdp. the normal inverse relationship between the qt interval and the heart rate also explains why the raw qt interval length must be corrected for heart rate to assess if the qt interval is prolonged.1,25 diagnosis of clqts: the possibility of clqts should be investigated in patients with qt intervals corrected for heart rate (qtc) calculated using the bazett formula (qtc=qt/ √rr interval) > 440 ms for males and > 460 ms for females (normal values). a definitive diagnosis is based on the extent of qtc prolongation and also requires consideration of other ecg issues (abnormal t waves or a history of tdp), clinical history of episodes suggesting clqts (syncope or palpitations), and family history of clqts or sudden cardiac death. the “schwartz criteria” delivers a diagnostic score based on these criteria and the anesthesia provider should consult the following references for a full understanding of how this score is determined.2,24,25,26 however 20-25% of patients with clqts confirmed by genetic testing have normal qt intervals.23 a qtc>500 ms strongly predicts clqts in asymptomatic patients with no significant family history.25 variation in t wave morphology, variability in the qt interval, and prolongation of the t wave all reflect abnormal and varying cardiac repolarization rates among different regions of the myocardium and are associated with tdp risk.25,29 one measure of abnormal and prolonged repolarization, increased transmural dispersion of repolarization (tdr), is quantified as the time from the peak of the t wave to its end (tpe). a prolonged tpe may actually reflect tdp risk more accurately than qtc alone in patients with clqts.26 values indicating elevated tpe are disease dependent but tpe>113 ms indicates arrhythmia risk in the general population.25 management of clqts: management includes avoiding triggers specific for the patient’s clqts type and medications that prolong the qt interval.3,23 qt prolonging antiarrhythmic medications include the class ia antiarrhythmics that slow conduction through the depolarized myocardium and block the ikr current (e.g. quinidine and procainamide) and the class iii antiarrhythmics that also block the ikr (including ibutilide and the nonselective beta blocking medication sotalol).25.26 amiodarone, a class iii antiarrhythmic medication, and verapamil, a calcium channel blocking medication, prolong the qtc and should be avoided in patients with clqts25 but produce a lower risk of tdp, probably because they do not increase tdr.11,26 for a full list of medications that prolong the qt interval see www.crediblemeds.org. a discussion of the impact of common perianesthetic agents on the qt interval is included in the section on “induction & maintenance of anesthesia” below. long-acting ß receptor antagonists are the mainstay of clqts medical treatment.3,23 however, they may be more effective for patients with lqt1, where they almost completely eliminate tdp episodes, than in lqt2 and 3.2 sodium channel blocking medications (e.g. mexiletine) can be added to beta blocking therapy for some patients with lqt3.23 their efficacy may depend on the patient’s specific mutation.2 implantable cardioverter defibrillators (icds) are recommended for patients with clqts who have survived an episode of scd or who continue to experience syncope despite ß receptor antagonists. but they are not without complications, including inappropriate shocks and the necessity of periodic additional procedures.3,5,23,30 first evaluated in 1991, left cardiac sympathetic denervation (lcsd) also shortens the qtc and can prevent episodes of tdp in 50% or more of symptomatic patients with clqts.6,30 lcsd is used for patients with clqts who remain symptomatic on optimized beta blocking therapy and for young children who are at higher risk for complications of icd insertion.23 the procedure is generally performed with the patient in the right lateral decubitus position. it can be accomplished either with thoracotomy or via minimally invasive video-assisted thoracoscopic surgery (vats) but one-lung ventilation is usually required.30,31 the mechanism by which lcsd reduces arrhythmias in patients with clqts is multifaceted. lcsd prevents efferent adrenergic outflow to the heart from the left sympathetic ganglia, reducing tachycardia and increasing the electrical stability of the myocardium. it also may increase parasympathetic cardiac efferent activity both by removing the sympathetic cardiac afferent pathways that usually inhibit it and by preventing release of the long-acting cardiac sympathetic co-transmitter neuropeptide y (npy), an inhibitor of postganglionic parasympathetic cardiac acetylcholine release.7 texas christian university “the science behind the art” volume 12 no.1 2024 anesthesia ejournal online issn 2333-2611 page 3 discussion while there are no definitive guidelines for the anesthetic management of patients with clqts, much can be learned from case studies and the recommendations of authoritative review articles. preoperative period: patients with diagnosed clqts requiring anesthesia will usually, but not always, be receiving ß receptor antagonists preoperatively.32,33 these medications must be continued on the day of surgery25, a precaution that has been called the most important preoperative intervention to reduce perioperative tdp risk in clqts, although adherence is not absolute.33 during the immediate preoperative period, patients with clqts should be maintained in quiet, warm surroundings and should receive adequate preoperative medication to reduce the sympathetic activity that accompanies anxiety.11,25 for pediatric patients with clqts, anxiolysis has been accomplished with midazolam.34,35,36 additional preoperative precautions for patients with clqts include cardiology consultation and scrutiny of the 12-lead ecg (including measurement of a baseline qtc), correction of electrolyte imbalances that can lengthen the qt interval (e,g, hypokalemia, hypomagnesemia, and hypocalcemia) and the placement of external defibrillator pads.11,25 patients with clqts who have icds should have the device’s function checked by a cardiologist.25,35,37 the importance of this precaution is illustrated by the case of a 7-year-old child with lqt2 and an icd who presented for myringotomy. after general anesthesia was induced with sevoflurane the patient developed tdp but the icd failed to function. the child was successfully defibrillated with an external defibrillator and the surgical procedure was cancelled. a postoperative chest x-ray revealed a fractured icd wire.36 intraoperatively, electromagnetic interference in the function of an icd, particularly the use of monopolar electrosurgery superior to the umbilicus, is a concern.38 icds can be left on if the surgery allows35 but turning off the antitachyarrhythmia functions of an icd can prevent unnecessary shocks.38 in some centers, icds are turned off for patients with clqts who are not pacemaker dependent once defibrillator pads and cardiac monitoring are instituted before induction.34 induction & maintenance of anesthesia: general anesthesia may prolong the qt interval even in patients without clqts39 possibly because hypothermia and positive pressure ventilation both prolong the qtc.11 neuraxial anesthesia has been used successfully in patients with clqts, including lqt240, although it also may prolong the qtc.39 during neuraxial anesthesia, the qtc prolonging effects of local anesthetic agents mostly occur if the drugs enter the systemic circulation at high levels.41 epidural anesthesia, which allows the gradual establishment of the desired level of sympathetic block to avoid hypotension, may be safer than “one shot” spinal blocks4,37 and epidural catheter insertion for intra and postoperative analgesia has also been successful.35 among intravenous (iv) anesthetic agents, ketamine increases the qtc and tdp risk via its sympathomimetic properties and should be avoided in patients with ltqs. propofol, midazolam, and fentanyl (and fentanyl analogues) do not increase qtc significantly and have all been used effectively. halogenated volatile anesthetics generally increase the qtc by blocking the ikr and iks currents responsible for repolarization.25,42,43,44 sevoflurane has seen extensive use in patients with clqts. however, even sevoflurane is listed among medications that prolong the qtc increasing tdp risk25,29, and expert consensus on the management of patients with clqts recommends avoiding all qtc prolonging medications.23 two centers that regularly perform cochlear implant surgery report the use of total iv anesthesia (tiva) with propofol, fentanyl (or an analogue), and a nondepolarizing muscle relaxant either exclusively45 or preferentially11 for patients with clqts (presumably mostly lqt1 and all patients ≤ 8 years of age) undergoing these procedures. potentially life-threatening perioperative arrhythmias occurred in 5 of the 45 (11%) cases in these two series, all of which were treated successfully with cardiac pacing. practitioners in these (and other) centers also administer magnesium iv prophylactically in this patient population to block calcium currents and reduce tdp risk.4,11,35,45 suxamethonium should not be used because it induces potassium shifts and causes sympathetic stimulation. pancuronium is also a poor choice for a muscle relaxant for patients with clqts because of its parasympathetic blocking properties.11 two case series of pediatric patients with clqts undergoing general anesthesia for a range of procedures, some of which were lqts-related (eg, icd insertion), may provide more generalizable results. a total of 179 patients underwent 272 procedures and 194 of these encounters (71%) involved exposure to inhalation anesthetics. adverse events including tdp occurred during 8/272 (3%) of these procedures. five of these adverse events occurred in patients undergoing lqts-related procedures, including 3 tdp episodes in neonates in the first day of life.32,33 in a case series of 22 patients ages 1 month to 17 years undergoing lcsd with general anesthesia (20 of whom had clqts) sevoflurane was employed as the induction agent for 11 (50%) while 10 (45%) received propofol. anesthesia was maintained with inhalation agents (predominantly isoflurane) in 19/22 = 86% of cases. no anesthetic complications occurred.35 the apparent low risk of sevoflurane for patients with clqts may be explained by the results of a randomized controlled study that assigned healthy children (age 1-16 years) scheduled for elective surgery to receive either tiva with propofol or inhalation anesthesia with sevoflurane. propofol increased neither the qtc nor the tdr as measured by tpe. sevoflurane increased the qtc but not the tpe.33 sevoflurane was also employed for anesthetic induction for a 17-month-old patient with clqts (presumably lqt1) undergoing cochlear implants47 and an 11-year-old patient with epilepsy and lqt2 undergoing an mri.47 in both cases, the airway was secured following the administration of propofol iv and general anesthesia was maintained with sevoflurane and propofol. no anesthetic complications occurred. similarly, a 5-year-old undergoing lcsd had anesthesia induced and underwent tracheal intubation following administration of fentanyl, propofol, and a nondepolarizing muscle relaxant. anesthesia was maintained with sevoflurane, fentanyl, and an epidural block without incident. (these cases also highlight the importance of suppressing the sympathetic response to laryngoscopy with adequate iv medications including propofol and fentanyl or an analogue.11,43) texas christian university “ the science behind the art” volume 12 no.1 2024 anesthesia ejournal online issn 2333-2611 page 4 sevoflurane anesthesia has been associated with tdp in patients with clqts, however. the 7-year-old patient with lqt2 who developed tdp after sevoflurane induction was described above.37 similarly, an adult with lqt2 experienced tdp during anesthesia with sevoflurane. as in the pediatric case, tdp for this adult was terminated with external defibrillation. then magnesium sulfate was administered iv, and an isoproterenol infusion (shortens the qtc) begun. the patient’s qtc was 497 ms preoperatively, 534 ms on the morning of postoperative day 1, and 495 ms later that day. the patient subsequently revealed that they had not taken prescribed ß receptor antagonists for 2 days before surgery.44 there is also a report of 4-year-old patient with undiagnosed clqts undergoing surgical correction of velopharyngeal dysfunction. while the patient was under sevoflurane anesthesia, the surgeon injected 1 ml of 1% lidocaine with 1:100,000 epinephrine into the surgical field, the patient’s heart rate increased from 113 bpm to 175 bpm, and tdp developed – which resolved spontaneously in 60 seconds.48 this case illustrates why some authors suggest that local anesthetics with epinephrine are contraindicated in patients with clqts.25 treatment of intraoperative tdp: if tdp does develop in patients with clqts under anesthesia the provider should discontinue the use of qt-prolonging medications (e.g. switch from inhalation anesthesia to tiva) and treat with iv magnesium sulfate, ß receptor antagonists (e.g. esmolol), and lidocaine, as well as cardiac pacing if needed.4,11,25,37,43 (the equipment to establish transvenous cardiac pacing/ defibrillation should be available in the or prior to induction.11) if tdp deteriorates into vf, standard resuscitation including external defibrillation has been used successfully.37,45 emergence from anesthesia: three patients, ages 11 to 15 years, with clqts developed arrhythmias (2 including vt) during emergence from general anesthesia with inhalation agents and directly after receiving anticholinesterase/ anticholinergic medications to reverse nondepolarizing neuromuscular blockage as well as ondansetron as prophylaxis against postoperative nausea and vomiting (ponv). all were treated successfully with ß receptor antagonists and/or lidocaine.32 anticholinesterase/ anticholinergic drug combinations as well as the antiemetics ondansetron and droperidol carry tdp risk for patients with clqts.25,29 dexamethasone has been used safely as an antiemetic.11,35,47 sugammadex does not substantially prolong the qtc – at least among healthy patients.25 the importance of preventing ponv in patients with clqts is illustrated by the case of an adult patient with syncope but no known clqts. this patient suffered from chronic diarrhea and was scheduled for esophagogastroduodenoscopy under monitored anesthesia care. after an uneventful procedure, the patient experienced ponv in the post anesthesia care unit (pacu) and received ondansetron and promethazine. about 1 hour later they developed a tachycardia (later identified as tdp) and then pulseless ventricular fibrillation, successfully treated with chest compressions and defibrillation. after resuscitation, the cqt was >600 ms and the serum potassium = 2.4 mmol/l. the patient received magnesium and potassium replacement iv.49 the initial symptom of diarrhea, the pre-procedure bowel prep, and the ponv may all have contributed to the hypokalemia that sparked this episode. summary and conclusions patients with clqts are a high-risk population and require special anesthetic precautions. the findings of this narrative review can be summarized as follows: • the most common types of clqts (lqt1-3) are caused by defects in genes coding for myocardial potassium or sodium channels. they cause delayed repolarization, a prolonged qtc, a prolonged tpe, and an elevated risk of sudden cardiac death. • clqts is diagnosed with the schwartz criteria and treated with ß receptor antagonists, icds, and lcsd. • pre-anesthetic precautions include the following: o consider cardiology consultation, o have function of the icd (if present) checked, o determine baseline qtc, o correct any electrolyte imbalances, o premedicate to prevent anxiety, o use of a warm, quiet preoperative waiting area, and o continue ß receptor antagonists on the day of surgery. • intraoperative, the anesthesia provider should: o apply external defibrillator pads and all standard monitors prior to induction, o turn off icd or adjust its settings to avoid electromagnetic interference, o monitor the qt interval, o have magnesium salts ready for administration if tdp develops and consider prophylactic administration for high-risk patients, o consider tiva and consider the use of sevoflurane if an inhalation agent is needed, o use propofol and/or fentanyl (or an analogue) to blunt the sympathetic response of airway manipulation, o avoid ketamine, suxamethonium, and pancuronium, and o maintain normothermia and avoid high inspiratory pressures. • if tdp does develop, the anesthesia provider should be prepared to: o give magnesium salts iv, o consider administration of ß receptor antagonists and lidocaine, o initiate cardiac pacing if pharmacologic treatment unsuccessful, and o initiate standard resuscitation including defibrillation if needed. • during emergence for anesthesia and in the pacu, the provider should: o consider alternatives to anticholinesterase/ anticholinergic drug combinations, o avoid droperidol or ondansetron but consider the use of dexamethasone as prophylaxis against ponv, o maintain the patient in a warm, quiet environment, o be aware that tdp may occur in the pacu. texas christian university “ the science behind the art” volume 12 no.1 2024 references 1. winbo a, paterson dj. the brain-heart connection in sympathetically triggered inherited arrhythmia syndromes. heart, lung and circulation. 2020;29:529–537. 2. singh m, morin dp, link ms. sudden cardiac death in long qt syndrome (lqts), brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia (cpvt). progress in cardiovascular diseases. 2019;62:227–234. 3. skinner jr, winbo a, abrams d. channelopathies that lead to sudden cardiac death: clinical and genetic aspects. heart, lung and circulation. 2019;28:22–30. 4. staikou c, chondrogiannis k, mani a. perioperative management of hereditary arrhythmogenic syndromes. british journal ofanaesthesia. 2012;108(5):730–744. doi:10.1093/bja/aes105. 5. epstein ae, dimarco jp, ellenbogen, ka, et al. 2012 accf/aha/hrs focused update incorporated into the accf/aha/ hrs 2008 guidelines for device-based therapy of cardiac rhythm abnormalities. jacc. 2013;61(3):e6–75. http://dx.doi. org/10.1016/j.jacc.2012.11.007. 6. schwartz pj, locati eh, moss aj. left cardiac sympathetic denervation in the therapy of congenital long qt syndrome: a worldwide report. circulation. 1991;84:503-511. 7. dusi v, de ferrari gm, pugliese l, et al. cardiac sympathetic denervation in channelopathies. frontiers in cardiovascular medicine. 2019;6:1-13. doi: 10.3389/fcvm.2019.00027. 8. kenyon ca, flick r, moir c, et al. anesthesia for videoscopic left cardiac sympathetic denervation in children with congenital long qt syndrome and catecholaminergic polymorphic ventricular tachycardia – a case series. pediatric anesthesia. 2010;20:465-470. 9. kitaura a, nakao s, hamasaki s, et al. sevoflurane prolonged the qtc interval and increased transmural dispersion of repolarization in a patient with long qt syndrome 3: a case report. ja clinical reports. 2017;3(29):1-4. doi 10.1186/s40981-017-00936. 10. schwartz pj, spazzolini c, crotti l, et al. the jervell and lange-nielsen syndrome: natural history, molecular basis, and clinical outcome. circulation. 2006;113:783-790. doi: 10.1161/circulationaha.105.592899. 11. scott-warren v, bendon a, bruce la, et al. cochlear implantation in children with congenital long qt syndrome: introduction of an evidence-based pathway of care. cochlear implants international. 2018;19(6):350-354. 12. jervell a, lange-nielsen f. congenital deaf-mutism, functional heart disease with prolongation of the qt interval, and sudden death. am. heart j. 1957;54(1):59-68. 13. fraser gr, froggatt p, murphy t. genetical aspects of the cardio -auditory syndrome of jervell and lange -nielsen (congenital deafness and electrocardiographic abnormalities). ann. hum. genet., lond. 1964;28:133-150. 14. romano c. congenital cardiac arrhythmia. the lancet. 1965;658-659. 15. wallace e, haward l, liu m, et al. long qt syndrome: genetics and future perspective. pediatric cardiology. 2019;40:1419– 1430. https://doi.org/10.1007/s00246-019-02151-x. 16. curren me, splawski i, vincent gm, et al. a molecular basis for cardiac arrhythmia: herg mutations cause long qt syndrome. cell. 1995;80:795-803. 17. wang q, shen j, splanaki i, et al. scn5a mutations associated with an inherited cardiac arrhythmia, long qt syndrome. cell. 1995;80:805-811. 18. neyroud n, tesson f, denjoy i, et al. a novel mutation in the potassium channels gene kvlqt1 causes the jervell and langeneilsen cardioauditory syndrome. nature genetics. 1997;15:186-189. 19. bezzina c, veldkamp mw, van den berg mp, et al. a single na+ channel mutation causing both long-qt and brugada syndromes. circ. res. 1999;85:1206-1213. 20. ackerman mj, priori sg, wilems s, et al. , hrs/ehra expert consensus statement on the state of genetic testing for the channelopathies and cardiomyopathies. heart rhythm. 2011; 8:1308 –1339. doi:10.1016/j.hrthm.2011.05.020. 21. crotti l, spazzolini c, tester dj, et al. calmodulin mutations and life-threatening cardiac arrhythmias: insights from the international calmodulinopathy registry. european heart journal. 2019;40:2964–2975. doi:10.1093/eurheartj/ehz311. 22. shimizu w, makimoto h, yamagata k, et al. association of genetic and clinical aspects of congenital long qt syndrome with life-threatening arrhythmias in japanese patients. jama cardiol. 2019:e1-e9. doi:10.1001/jamacardio.2018.4925. 23. priori sg, wilde aa, horie m, et al. hrs/ehra/aphrs expert consensus statement on the diagnosis and management of patients with inherited primary arrhythmia syndromes. heart rhythm. 2013;10(12):1932-1963. http://dx.doi.org/10.1016/j. hrthm.2013.05.014. anesthesia ejournal online issn 2333-2611 page 5 texas christian university “ the science behind the art” volume 12 no.1, 2024 24. sharma n, cortez d, disori k. a review of long qt syndrome: everything a hospitalist should know. hospital pediatrics. 2020;10(4):1-7. doi:https://doi.org/10.1542/hpeds.2019-0139. http://hosppeds.aappublications.org/content/early/2020/03/04/hpeds.2019-0139. 25. niimi n, yuki k, zaleski k. long qt syndrome and perioperative torsades de pointes: what the anesthesiologist should know. journal of cardiothoracic and vascular anesthesia. 2022; 36:286-302. 26. kaye ad, volpi-abadie j, bensler mj. qt interval abnormalities: risk factors and perioperative management in long qt syndromes and torsades de pointes. j anesth. 2013;27:575–587. doi 10.1007/s00540-013-1564-1. 27. kistamás k, veress r, horváth b, et al. calcium handling defects and cardiac arrhythmia syndromes. front. pharmacol. 2020;11(72):1-25. doi: 10.3389/fphar.2020.00072’ 28. neira v, enriquez a, simpson c, baranchuk a. update on long qt syndrome. j. cardiovasc. electrophysiol. 2019;30:3068-3078. doi: 10.1111/jce.14227. 29. staikou c, stamelos m, stavroulakis e. impact of anaesthetic drugs and adjuvants on ecg markers of torsadogenicity. british journal of anaesthesia. 2014;112(2):217-230. doi:10.1093/bja/aet412. 30. costello jp, wilson jk, louis c, et al. surgical cardiac denervation therapy for treatment of congenital ion channelopathies in pediatric patients: a contemporary, single institutional experience. world journal for pediatric and congenital heart surgery. 2015;6(1):33-38. doi: 10.1177/2150135114555203. 31. collure ca, johnson jn, moir c, ackerman mj. left cardiac sympathetic denervation for the treatment of long qt syndrome and catecholaminergic polymorphic ventricular tachycardia using video-assisted thoracic surgery. heart rhythm. 2009;6:752759. 32. nathan at, berkowitz dh, montenegro lm, et al. implications of anesthesia in children with long qt syndrome. anesth. analg. 2011;112:1163-1168. doi: 10.1213/ane.0b013e3182121d57. 33. whyte sd, nathan a, myers d, et al. the safety of modern anesthesia for children with long qt syndrome. anesth. analg. 2014;119:932-938. doi: 10.1213/ane.0000000000000389. 34. kenyon ca, flick r, moir c, et al. anesthesia for videoscopic left cardiac sympathetic denervation in children with congenital long qt syndrome and catecholaminergic polymorphic ventricular tachycardia – a case series. pediatric anesthesia. 2010;20:465–470. doi:10.1111/j.1460-9592.2010.03293.x 35. kaur m, ramakumar n, yadav s, subramaniam r. recurrent syncope in a child and video assisted thoracoscopic surgery the long and short of it. indian journal of anaesthesia. 2019;63(10):847-850. doi: 10.4103/ija.ija_180_19. 36. coleman m. imundo jr, cortez d, et al. torsades de pointes during myringotomy in a child with congenital long qt syndrome: a case report. am. j case rep. 2020;21: e925602. doi: 10.12659/ajcr.925602. https://www.amjcaserep.com/abstract/index/idart/925602. 37. straudt ge, watkins sc. anesthetic considerations for pediatric patients with congenital long qt syndrome. journal of cardiothoracic and vascular anesthesia. 2019;33:2030-2038. https://doi.org/10.1053/j.jvca.2018.11.005. 38 apfelbaum jl, schulman pm, mahajan a, et al. practice advisory for the perioperative management of patients with cardiac implantable electronic devices: pacemakers and implantable cardioverter–defibrillators 2020. anesthesiology. 2020;132(2):225–252. 39. duma a, pal s, helsten d, et al. high-fidelity analysis of perioperative qtc prolongation. anesth. analg. 2016;122:439–448. doi: 10.1213/ane.0000000000001023. 40. ishizaki h, murata h, maekawa t, et al. successful vaginal delivery in a parturient with long qt syndrome type 2 using double-catheter epidural analgesia. medicine. 2021;100:47. http://dx.doi.org/10.1097/md.0000000000027790. 41. biernawska j, kaźmierczak j, kotfis k, żukowski m. the influence of regional anaesthesia and local anaesthetics on cardiac repolarization. anaesthesiology intensive therapy. 2016;48(2): 135–141. 42. park wk, pancrazio jj, suh ck, lynch c. mycocardial depressant effects of sevoflurane. anesthesiology. 1996;84:1166-1176. 43. booker pd, whyte sd, ladusans ej. long qt syndrome and anaesthesia. british journal of anaesthesia. 2003;90(3):349-366. doi: 10.1093/bja/aeg061. 44. kumakura m, hara k, sata t. sevoflurane-associated torsade de pointes in a patient with congenital long qt syndrome genotype 2. journal of clinical anesthesia. 2016;33:81–85. http://dx.doi.org/10.1016/j.jclinane.2016.03.011. 45. anto r, maheswari s, vadivu s kameswaran m. cochlear implantation in congenital long-qt syndrome: a comprehensive study. j. in.t adv. otol. 2019;15(3):352-357. doi:10.5152/iao.2019.7404. 46. yaman f, baydogan n, bilir a, incesulu a. anesthesia for a child with congenital long qt syndrome, a case report and literature review. anesthesia: essays and researches. 2021;15(1):149-151. doi:10.4103/aer.aer_48_21. texas christian university “ the science behind the art” volume 12 no.1 2024 47. ghimire a, banoub rw, tobias jd. anesthetic care of a child harboring the kcnh2 gene. j. med. cases. 2022;13(1):40-43. doi: https://doi.org/10.14740/jmc3870. 48. jeon s, lee h-j, jung y-h, et al. concealed congenital long qt syndrome during velopharyngeal dysfunction correction: a case report. j. dent. anesth. pain med. 2020;20(3):165-171. https://doi.org/10.17245/jdapm.2020.20.3.165. 49. schaar s, liu m, patzkowski m. torsades de pointes in the pacu after outpatient endoscopy: a case report. bmc anesthesiology. 2021;21:302. https://doi.org/10.1186/s12871-021-01457-9. summary of key points • the most common types of clqts (lqt1-3) are caused by defects in genes coding for myocardial potassium or sodium channels. patients with clqts are at risk for vt in the tdp pattern from adrenergic stimulation, including that which occurs during the perioperative period. • clqts is diagnosed using the schwartz criteria and treated with ß receptor antagonists, icds, and lcsd. • pre-anesthetic precautions include cardiology consult, determining a baseline qtc, correcting electrolyte imbalances, premedicating to prevent anxiety, using a warm quite preoperative waiting area, and continuing beta blocking medications on the day of surgery. • intraoperative precautions include applying external defibrillation pads and all monitors prior to induction, ensuring that no electromagnetic interference occurs to the icd, monitoring the qt interval, avoiding medications that prolong the qt interval, blunting the adrenergic response to laryngoscopy with adequate medication, considering tiva but favoring the use of sevoflurane if an inhalation agent is required, maintaining normothermia, avoiding high inspiratory pressures, and being prepared to administer magnesium salts iv if tdp develops. • during emergence from anesthesia the provider should consider alternatives to anticholinesterase/ anticholinergic drug combinations, consider the use of dexamethasone as prophylaxis against ponv, maintain the patient in a warm, quiet environment, and be aware that tdp may occur in the pacu. texas christian university “ the science behind the art” volume 12 no.1 2024 volume 9no. 1 2021 educated hand publishing llc “the science behind the art” volume 9 no.1 2021 anesthesia ejournal online issn 2333-2611 page 1 anesthetic management of a patient with hereditary coproporphyria audrey f. fisher, bsn, rn, rrna affiliation: texas christian university grant/financial support: none biographical data: audrey f. fisher is a registered nurse pursuing her dnp in nurse anesthesia at texas christian university in fort worth, texas. keywords: hereditary coproporphyria, porphyria, triggering agents, acute attacks abstract hereditary coproporphyria (hcp) is an inborn error of metabolism that causes accumulation of porphyrins and porphyrin precursors, which can potentially lead to neurotoxicity and acute crisis with introduction of a triggering agent. many anesthetic drugs have been labeled porphyrinogenic, therefore safe anesthetic management of patients with hcp demands understanding of the disease process. although most of the current clinical reports are anecdotal and/or outdated, there is consensus that unsafe agents include: barbiturates, ketamine, and etomidate; and safe agents include: propofol, nitrous oxide, volatile agents, all neuromuscular blocking agents, all reversal agents, commonly used narcotics, antiemetics (excluding metoclopramide), and sedatives. acute attacks of hcp exhibit a wide variety of metabolic defects that may result in life-threatening reactions, such as severe autonomic dysfunction and blood pressure (bp) lability. the anesthesia provider must be knowledgeable of concomitant triggers as well as appropriate treatment of porphyric crises. further investigation of anesthetic management of the patient with hcp is indicated, given that most current clinical reports are anecdotal and/or outdated. the anesthesia provider should refer to the american porphyria foundation website for the most up-to-date information on porphyria and up-to-date drug database for healthcare professionals caring for porphyria patients aej powerpoint template ©2009 texas christian university, center for instructional services. for educational use only. content is the property of the presenter and their resources. introduction • hcp is a rare (1:1,000,000) heme biosynthesis disorder inherited from either parent via autosomal dominance. • hcp causes accumulation of porphyrins and porphyrin precursors which lead to neurotoxicity and subsequent acute attack in the presence of known triggering agents. • acute attacks can be life threatening and involve severe autonomic instability, respiratory failure, and paralysis. • triggering agents include many anesthetic agents that have been labeled porphyrinogenic; see table 1. • safe anesthetic management of patients with hcp demands understanding of this disease process. purpose • this case report describes the pathophysiology and anesthetic management of a patient with hereditary coproporphyria (hcp). discussion • the patient was at increased risk of an attack of acute porphyria due to pmh of hcp combined with the necessity to undergo general anesthesia. • the decision to substitute the planned sevoflurane with isoflurane was an attempt to prevent an exacerbation of porphyria. • the patient did not have any porphyrinogenic-related reactions to the anesthetic agents administered intraoperatively. key points • identifying drugs as either safe or unsafe is critical. • anxiolysis with benzodiazepines is recommended. • safe anticonvulsant therapy includes levetiracetam, clonazepam, gabapentin, and/or vigabatrin for seizure prevention. • correction or prevention of hyponatremia and electrolyte imbalances is recommended. • iv hydration with glucose containing fluids (not to exceed 300 g/day) to downregulate aminolaevulinic acid synthetase (alas) and to minimize caloric restriction and dehydration. • general and regional anesthesia are both possible and equally efficacious if initiating factors are avoided. • arterial line for hemodynamic monitoring is recommended due to likelihood of autonomic dysfunction. • if a severe attack is suspected, iv heme (panhematin) should be administered expeditiously. case critique • although the patient was not anxious or agitated preoperatively, administration of an anxiolytic to reduce stress, a known trigger of porphyria, is indicated. • the patient received dexamethasone despite many studies claiming it to be unsafe. • it is widely established that sevoflurane is safe. anesthetic management of a patient with hereditary coproporphyria audrey f. fisher, bsn, rn, ccrn, texas christian university case description • a 63-year-old, 101 kg, 180 cm, male presented for a right parietal temporal craniotomy for a glioblastoma tumor resection after suffering frequent left sided falls at home and subsequent loss of consciousness. pre-anesthetic evaluation • medical history: coronary artery disease, carotid stenosis, tobacco use, gastroparesis, pemphigus vulgaris, schizophrenia, and hcp. • surgical history: cataract surgery and heart catheterization. • current medication regimen: metoprolol, vitamin c, amlodipine, labetalol, nicotine patch, levetiracetam, famotidine, dexamethasone, risperidone, clonazepam, benztropine, and aspirin. • diagnostic testing: mri diagnosed 7.5 cm right temporal lobe mass with a left midline shift of 7 mm, abnormal labs wbc 17.6 and glucose 151. intraoperative anesthetic management • pre-induction vital signs: pulse 81 in nsr, bp 125/78 mm hg, spo2 100%, rr 20, and temperature 35.1 °c. • general anesthetic induction: fentanyl 100 mcg iv, lidocaine 100 mg iv, propofol 100 mg iv, and succinylcholine 140 mg iv. • 8.0 ett placed followed by isoflurane titrated to 0.5 mac. • remifentanil and phenylephrine infusions. • arterial line and internal jugular central line placed. • patient placed in prone position with head in mayfield keep skull pins which were verified and secured by the surgeon. intraoperative course • preoperatively patient calm, pleasantly confused and denied discomfort. • no signs of acute attack of porphyria. postoperative course • patient transported to neuro icu and remained intubated on mechanical ventilator and fentanyl, propofol, and nicardipine infusions. references 1. american porphyria foundation website. updated 2021. accessed february 13, 2021. https://porphyriafoundation.org. 2. jensen nf, fiddler d s, striepe v. anesthetic considerations in porphyrias. anes analg.1995;80(3). 591-599. 3. genetic and rare diseases information center website. updated april 9, 2019. accessed february 15, 2021. https://rarediseases.info.nih.gov. 4. rapp hj, james m, bonkovsky. anaesthesia recommendations for patients suffering from porphyria. orphan anesthesia website. updated december 2014. accessed february 15, 2021. https://www.orpha.net/data/patho/ans/en/porphyria_en.pdf. 5. hines rl, marschall ke. chapter 19: inborn errors of metabolism. in: tantawy h, tao j. stoelting’s anesthesia and co-existing disease. 7th ed. elsevier inc; 2018:377-384. 6. findley h, philips a, cole d, nair a. porphyrias: implications for anaesthesia, critical care, and pain medicine. continuing educ anes crit care pain. 2012;12(3). 128-133. conclusions and recommendations • a thorough perioperative workup must be performed in order to prevent an acute attack of porphyria which can be life-threatening. • determination of safe vs unsafe anesthetic medications is key. • no evidence suggests a general anesthetic is safer than a regional anesthetic. • further investigation of anesthetic management of the patient with hcp is required because most of the current clinical reports are anecdotal and/or outdated. • refer to the american porphyria foundation website for the most up-to-date information on porphyria and up-to-date drug database for healthcare professionals. pathophysiology and manifestations • heme is a vital porphyrin to hemoglobin because it is required to transport o2, remove co2, and biotransform essential enzymes such as cyp450; see figure 2. • the porphyrias, a group of metabolic disorders, each lack any 1 of the 8 enzymes in the heme synthetic pathway resulting in the accumulation of porphyrin and porphyrin precursors ala and pbg, subsequently producing a form of porphyria; see figure 1. • hcp lacks cpo, the 6th enzyme in the heme biosynthesis pathway, which originates from a genetic mutation of the cpox gene on chromosome 3; see figure 3. • manifestations: acute abdominal pain, cutaneous lesions, neuropsychiatric abnormalities such as confusion, seizures, mood disturbance, hysteria, syncope, autonomic instability, peripheral neuropathy, sensory loss and ascending muscle weakness mimicking guillain-barre; see figure 4. cpox gene mutation on chromosome 3 at position 12 vs safe agents •propofol •nitrous oxide •volatile agents •depolarizing and nondepolarizing nmb •reversal agents •antiemetics (excluding reglan)* unsafe agents •barbiturates •ketamine •etomidate •decadron* •calcium channel blockers* •ketorolac* potential of drugs to provoke hcp attacks *majority consensus table 1. triggering agents figure 1. heme synthesis pathway figure 2. hemoglobin molecule figure 3. location of cpox gene mutation figure 4. apparent vs nonapparent symptoms magnesium-sulfate galley poster.jpeg volume 9no. 11 2021 educated hand publishing llc “the science behind the art” volume 9 no.11 2021 anesthesia ejournal online issn 2333-2611 page 21 magnesium sulfate: a multi-modal adjunct for post-operative analgesia cody r. justice, bsn, rn, rrna, fort worth, tx affiliation: texas christian university grant/financial support: none biographical data: cody r. justice is a resident registered nurse anesthetist pursuing his dnp in nurse anesthesia at texas christian university in fort worth, texas. keywords: magnesium sulfate, multi-modal, post-operative, non-opioid, and analgesia abstract the goal of multi-modal analgesia is to minimize the use of opioid analgesics intra-operatively and in recovery.1 magnesium sulfate(mgso4), a physiological cation, serves as a multi-modal adjunct in the reduction of opioid use in the peri-operative setting.2,7 historically, opioids have been the choice of providers in treating and controlling pain.2,4 recent literature supports the use of a multi-modal approach to control pain and reduce the amount of opioid used.1-6,8 mgso4, an inexpensive and safe alternative to opioids, has been shown to reduce the amount of opioids used in recovery.3,6 mgso4 is an endogenous electrolyte and antagonist at the nmda receptor blocking the entry of calcium into the cell.2,3,7 the entry of calcium ignites numerous nociceptive pathways leading to a chronic pain and a hypersensitivity state to noxious stimuli.7 by antagonizing the nmda receptor, mgso4 prevents patients from a heightened reaction to stimuli and reduction in opioid use.7 therefore, the use of mgso4 as part of a multi-modal analgesia approach should be used during anesthesia management to reduce postoperative pain and the consumption of opioids during and after surgery.1,4,6 the purpose of this case report is to analyze the analgesic effects of mgso4 in multi-modal pain management. aej volume 5 no. 4 2017 educated hand publishing llc “the science behind the art” volume 5 no. 4 2017 anesthesia ejournal online issn 2333-2611 page 23 efficacy of intranasal dexmedetomidine as a preoperative anxiolytic in children: a systematic review eric r. wood, msna, crna affiliation: university of alabama funding/conflict of interest disclosure: none declared keywords: dexmedetomidine, premedication, anxiety, intranasal, children introduction preoperative anxiety and fear affect up to 60% of pediatric patients and can lead to enuresis and delayed recovery from surgery.1,2 ten percent of children with high preoperative anxiety go on to experience emergence delirium in the recovery room.2 moreover, anxiety can increase stress for patients and their families and can delay the induction of anesthesia and the start of surgery.2 of those children who experience preoperative anxiety, 50% will continue to exhibit negative behavior changes at 2 weeks after surgery.1,2 negative behavior changes continue in 20% of children at 6 months and in 7.5% of children at 1 year.1,2 the most common negative behavior responses include separation anxiety, eating problems, nightmares, aggression toward authority, and temper tantrums.1,2 problems with eating and sleeping may be attributable to the fact that children with increased preoperative anxiety often experience a more painful and slower recovery than those with low anxiety levels.2 predictors of preoperative anxiety include increased parental anxiety, a low activity level, a less sociable temperament, and a history of poor-quality medical encounters.1 it is important to identify these at-risk children so that anesthesia providers can mitigate the negative effects by reducing or preventing preoperative anxiety. anesthesia providers commonly administer preoperative sedatives that help to reduce anxiety for the child and expedite anesthesia induction and surgery.3-5 midazolam, a benzodiazepine receptor agonist that causes sedation and amnesia, is the most common premedication for children,4-7 and its benefits include a short duration of action and a reduction in the incidence of postoperative vomiting.7 midazolam is most commonly delivered to children by the oral route, but this method has several disadvantages, including restlessness, cognitive impairment, and respiratory depression.6,8 use of midazolam is hampered by low bioavailability that results in a slow onset and a bitter aftertaste that can reduce compliance to as low as 45%.9 ketamine is another popular premedication that causes dissociative anesthesia, sedation, and analgesia in children.4,5,10 side effects of ketamine include nausea and vomiting, excessive salivation, nystagmus, and psychological disturbances such as emergence delirium.10 dexmedetomidine (dex) is a highly selective alpha-2 adrenergic agonist that produces sedation, analgesia, and anxiolysis without causing respiratory depression.11 other benefits of dex include its ability to increase glomerular filtration and abstract preoperative anxiety is a common problem in pediatric patients that can have many negative effects; oral premedications (eg, midazolam) are often used to reduce anxiety and improve compliance. dexmedetomidine (dex) is an alpha-2 receptor agonist that can be given intranasally to children as a premedication and may be useful as an anxiolytic. in this systematic review of the pubmed, cinahl, ovid, and cochrane library databases, the efficacy of intranasal dexmedetomidine (in dex) was compared with that of oral midazolam for relieving preoperative anxiety among pediatric surgical patients. three trials were assessed: 2 of these trials concluded that in dex was a superior anxiolytic for use in children; the third showed that there was no significant difference. more rigorous research that includes a larger sample size and an objective measurement tool is needed before drawing conclusions. aej anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 4 2017 page 24 to decrease salivation, intraocular pressure, and the shivering threshold.12 preliminary studies report that dex is effective for the prevention and treatment of postoperative emergence delirium,13-15 and there is a growing trend among anesthesia providers to deliver dex by the intranasal (in) route. the bioavailability of intranasal dexmedetomidine (in dex) is high (65%), and it does not cause discomfort when administered by this route.12,16 the nasal mucosa offers better absorption, faster onset, and better compliance without gastric stimulation, painful needle sticks, or a high risk of aspiration.10,17 in dex has shown promise as an alternative to oral agents for premedication in children. the purpose of this systematic review was to identify whether there was a difference in anxiety levels among pediatric patients who received in dex or oral anxiolytics as premedication. methods search strategy and trial selection the following databases were searched during the period from september 25, 2016, to october 31, 2016: pubmed (national library of medicine), cinahl (ebsco), cochrane database of systematic reviews (the cochrane collaboration), and ovid. the medical subject headings (mesh) terms used in the search strategy were as follows: dexmedetomidine, premedication, anxiety, intranasal, and children. all searches were initially performed without restrictions. the results were then moved to refworks (proquest) and checked for duplications, which were removed. titles and abstracts of randomized controlled trials (rcts) were screened for historical significance. as premedication via the intranasal route is a relatively new technique, the results were restricted to articles published within the past 5 years. inclusion and exclusion criteria articles were required to meet the following inclusion criteria: (1) have an rct design, (2) be original research comparing premedication with in dex to a single oral premedication, (3) report anxiety or behavior before induction of anesthesia as a primary outcome, and (4) examine pediatric patients aged 2 to 12 years with an american society of anesthesiologists physical status of i to ii18 and who were undergoing elective surgery. studies were excluded if they examined children with mental or physical deficiencies, chronic pain, or any condition that placed them in a physical status category above ii. titles and abstracts were screened for the inclusion and exclusion criteria. full texts were then retrieved for any publication that met the defined criteria. a flow diagram of the study search algorithm is shown in figure 1. figure 1. search algorithm anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 4 2017 page 25 results description of the included studies three studies were included in the final analysis. the characteristics of the studies by yuen et al,19 ghali et al,20 and linares segovia et al21 are summarized in table 1. all studies compared premedication with in dex to premedication with oral midazolam and used preoperative anxiety at the time of transferring the child from the parent to the operating room as the primary outcome. in the studies by yuen et al and linares segovia et al, the participants were given a premedication 60 min before the induction of general anesthesia.19,21 however, in the trial by ghali et al, one group of participants was given in dex 60 min before the induction of general anesthesia, whereas another group of participants was given oral midazolam 30 min before the induction of general anesthesia.20 measurement of anxiety anxiety was measured differently in the studies. in an older study by yuen et al, the participants were given premedication 60 min before the induction of general anesthesia; the authors measured anxiety by evaluating behavior at parental separation by using a 4-point likert-type behavior scale (a score of 1 indicated “calm and cooperative” and a score of 4 indicated “crying or resisting”).19 by contrast, both ghali et al and linares segovia et al utilized the validated modified yale preoperative anxiety scale (mypas) to evaluate anxiety at the time of transfer to the operating room.20-22 the mypas, which can be performed by an observer in less than 1 min,20 contains 22 items within 5 categories.20,21 the categories include activity, emotional expressivity, state of arousal, vocalization, and use of adults.20,21 scores range from 23 to 100, with an increased score indicating an increased anxiety state.20 primary conclusions at the time of parental separation, yuen et al found no significant difference in behavior scores between the oral midazolam group and the 2 in dex dose groups (p = 0.771).19 in contrast, ghali et al and linares segovia et al found that the patients in the in dex group had significantly lower anxiety levels than did patients in the oral midazolam group (p = 0.029 and p = 0.036, respectively).20,21 similarly, linares segovia et al found that at 60 min after receiving premedication, anxiety was significantly lower among children who received in dex than among those who received oral midazolam (p = 0.001).21 a risk analysis also showed that in dex reduced the risk of anxiety by 28% at 60 min.21 table 1. characteristics of the included studies study design intervention no. age, y (mean) sex (m/f) ps linares segovia et al21 prospective, randomized, doubleblind controlled trial a. dex 1 mcg/kg in 60 min before induction b. midazolam 0.5 mg/kg po 60 min before induction a. 52 b. 56 a. 4 b. 4 a. 24/28 b. 32/24 i ghali et al20 prospective, randomized, doubleblind controlled trial a. dex 1 mcg/kg in 60 min before induction b. midazolam 0.5 mg/kg po 30 min before induction a. 60 b. 60 a. 8.2 b. 8.1 a. 34/26 b. 28/32 i yuen et al19 prospective, randomized, doubleblind controlled trial a. dex 1 mcg/kg in 60 min before induction b. dex 0.5 mcg/kg in 60 min before induction c. midazolam 0.5 mg/kg 30 min before induction a. 32 b. 32 c. 32 a. 6.1 b. 6.8 c. 6.4 a. 30/2 b. 29/3 c. 30/2 i or ii abbreviations: dex, dexmedetomidine; in, intranasal; po, by mouth; ps, american society of anesthesiologists physical status. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 4 2017 page 26 additional outcome measures two of the studies measured anxiety at the time of induction as an additional primary outcome.20,21 in the study by yuen et al, there was no significant difference in behavior scores at induction of general anesthesia among the 3 groups (p = 0.148).19 the results of the study by linares segovia et al differed with those of the yuen et al study, concluding that patients who received in dex experienced significantly less anxiety at induction of anesthesia than did those who received oral midazolam (p = 0.04).21 in addition to these primary outcomes, all 3 studies also examined the hemodynamic effects of the premedications as secondary outcomes.19-21 the methods of hemodynamic assessment and the statistically significant findings of each study are shown in table 2. although all studies found that in dex produced statistically significant hemodynamic changes, there were no clinically significant adverse effects. risk of bias in all of the studies, the authors implemented random selection methods to ensure a low risk of selection bias.19-21 although the participants understood that they were undergoing a minor surgical procedure, researchers in all of the studies used doubleblinding to minimize the risks of both performance bias and detection bias.19-21 ghali et al and linares segovia et al used the validated mypas to assess anxiety,20,21 whereas yuen et al used a likert-type scale.19 the scale did not include a midpoint, which can force a biased response (positive or negative).19,23 yuen et al and ghali et al performed a power analysis and met their sample goal.19,20 linares segovia et al performed a power analysis and calculated that a sample of 75 participants was needed per group (n = 150); however, the researchers were only able to enroll 108 patients.21 thus, sampling bias limited our ability to draw useful conclusions from the results of that study. table 2. significant hemodynamic findings study method spo2 hr bp linares segovia et al21 hr, spo2, and bp were measured at baseline and every 15 min after drug administration spo2 decreased 1.5% at 30 min in the dex group (p = 0.001) spo2 decreased 1.2% at 15 min in the midazolam group (p = 0.001) hr decreased by 8 bpm at 45 min in the dex group (p = 0.001) map decreased by an average of 5 mm hg at 30 min in the dex group (p = 0.005) ghali et al20 hr, spo2, and bp were measured at baseline and every 10 min after drug administration no statistically significant findings at transfer to or, hr was significantly less in the dex group (85 bpm) than in the midazolam group (96 bpm) (p = 0.036) at transfer to or, sbp was significantly less in the dex group (92 mm hg) than in the midazolam group (105 mm hg) (p = 0.032) yuen et al19 hr, spo2, and bp were measured at baseline and every 15 min after drug administration no statistically significant findings hr decreased by 11.1% and 16.4% from baseline in group d0.5 and group d1 at 60 min, respectively sbp decreased by 14.1% at 60 min in group d1 abbreviations: bp, blood pressure; bpm, beats per minute; d0.5, 0.5 mcg/kg in dex; d1, 1 mcg/kg in dex; dex, dexmedetomidine; hr, heart rate; in, intranasal; map, mean arterial pressure; or, operating room; sbp, systolic bp; spo2, oxygen saturation. discussion and limitations there was no consensus among the 3 studies regarding the superiority of in dex over oral midazolam as a preoperative anxiolytic.19-21 all of the studies measured anxiety with subjective scales, which increased the likelihood of inconsistency. whereas yuen et al utilized a 4-point behavior scale to assess anxiety, the other studies used the mypas.19 ideally, all of the studies would have utilized the same validated scale. nevertheless, it is noteworthy that the study by yuen et al, which found no significant differences between therapies, used a simplistic 4-point behavior scale to assess anxiety.19 moreover, the outcomes in that study were simply reported as “satisfactory” or “unsatisfactory” without either term being defined, and with no mean behavior scores being documented.19 we think it is fair to say that this method was less rigorous,19 and that the trials by ghali et al and linares segovia et al were more reliable as demonstrated by their reproducibility with similar methods.20,21 none of the studies evaluated the onset time or peak effect of the administered drugs. in all of the studies, in dex was administered 60 min before induction of general anesthesia.19-21 the average time a pediatric patient spends in the preoperative holding area is less than 50 min.24,25 ideally, the authors would have given the medication within this average time (ie, 30–45 min before induction). although there is a great deal of clinical data concerning the use of dex in children, its use has not been approved for premedication, which is still an off-label indication. anesthesia providers must always consider the risks and benefits when selecting a medication, and this should be no different in the case of in dex. however, the results of this analysis indicate that in dex was safe and may be especially useful when an anesthesia provider is concerned about emergence delirium, analgesia, or compliance. in conclusion, this systematic review was performed to compare the efficacy of in dex with that of oral midazolam as a preoperative anxiolytic in children. three rcts were selected and critically reviewed, but the results were inconclusive. because the studies by ghali et al and linares segovia et al were more reliable and used similar methods,20,21 we think it is fair to conclude that the evidence favors in dex having beneficial effects. an ideal study would be one with a large sample size and an objective measurement tool in which in dex is administered 30 to 45 min before induction of general anesthesia. while in dex appears to be a safe and effective alternative to oral midazolam, additional rigorous studies are needed before any practice recommendations can be made. anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 4 2017 page 27 anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 4 2017 page 28 references 1.  kain zn, mayes lc, o’connor tz, cicchetti dv. preoperative anxiety in children. predictors and outcomes. arch pediatr adolesc med. 1996;150(12):1238-1245. https://doi.org/10.1001/archpedi.1996.02170370016002. 2.  kain zn, mayes lc, caldwell-andrews aa, karas de, mcclain bc. preoperative anxiety, postoperative pain, and behavioral recovery in young children undergoing surgery. pediatrics. 2006;118(2):651-658. https://doi.org/10.1542/ peds.2005-2920. 3.  fortier ma, 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https://doi.org/10.1007/s00228-011-1002-y https://doi.org/10.4103/0259-1162.118954 https://doi.org/10.4103/0259-1162.118954 https://doi.org/10.4103/0019-5049.79879 https://doi.org/10.1213/ane.0b013e31816c8929 https://doi.org/10.4103/1658-354x.87268 anesthesia ejournal www.anesthesiaejournal.com volume 5 no. 4 2017 page 29 21.  linares segovia b, garcia cuevas ma, ramirez casillas il, et al. pre-anesthetic medication with intranasal dexmedetomidine and oral midazolam as an anxiolytic. a clinical trial. an pediatr (barc). 2014;81(4):226-231. https://doi.org/10.1016/j. anpedi.2013.12.006. 22.  kain zn, mayes lc, cicchetti dv, bagnall al, finley jd, hofstadter mb. the yale preoperative anxiety scale: how does it compare with a “gold standard”? anesth analg. 1997;85(4):783-788. https://doi.org/10.1213/00000539-199710000-00012. 23.  james t. croasmun, lee ostrom. using likert-type scales in the social sciences. j adult educ. 2011;40(1):19. http://search. proquest.com/docview/1018567864 24.  maclaren je, hammell c, novoa c, mednick l, kain zn. how much time do we spend in preoperative holding: findings of a video capture system. anesthesiology. 2007;107:a1646. 25.  kain zn, maclaren je, hammell c, et al. healthcare provider-child-parent communication in the preoperative surgical setting. paediatr anaesth. 2009;19(4):376-384. https://doi.org/10.1111/j.1460-9592.2008.02921.x. https://doi.org/10.1016/j.anpedi.2013.12.006 https://doi.org/10.1016/j.anpedi.2013.12.006 https://doi.org/10.1213/00000539-199710000-00012 http://search.proquest.com/docview/1018567864 http://search.proquest.com/docview/1018567864 https://doi.org/10.1111/j.1460-9592.2008.02921.x texas christian university “the science behind the art” volume 10 no.3 2022 anesthesia ejournal online issn 2333-2611 page 1 negative pressure pulmonary edema christine nagel, rn, bsn, ccrn affiliation: texas christian university grant/financial support: none keywords: negative pressure pulmonary edema, nppe, laryngospasm abstract negative pressure pulmonary edema (nppe) is a rare but dangerous complication of general anesthesia potentially causing anoxic brain injury and a 5% mortality, if not promptly recognized and treated. this case report reviews an 18-year-old male who developed nppe after a pilonidal cyst removal under general anesthesia. the purpose of this poster is to educate professionals on the etiology, signs, symptoms, treatments, risk factors, and preventions of nppe to aid in the early recognition and treatment of its occurrence. aej volume 10no. 3 2022 about the author: christine nagel, is a graduate student pursing a doctorate of nurse anesthesia practice from texas christian university school of nurse anesthesia. texas christian university “the science behind the art” volume 10 no.3 2022 anesthesia ejournal online issn 2333-2611 page 2 powerpoint template ©2009 texas christian university, center for instructional services. for educational use only. content is the property of the presenter and their resources. background of nppe § picot: in surgical patients, how is negative pressure pulmonary edema (nppe) best prevented and treated compared to the traditional methods of intubation and mechanical ventilation to provide safer anesthesia care during the perioperative period? § nppe is a rare, life-threatening complication of general anesthesia §incidence: 0.01-0.1% of all general anesthetics • etiology: non-cardiogenic •large negative intrathoracic pressure produced by forceful inspiration against a closed glottis •increased pulmonary capillary permeability and enhanced venous return to the heart leads to fluid accumulation in the alveoli from the intravascular system • type 1 nppe: occurs immediately due to obstruction • type 2 nppe: delayed appearance; due to relief of a chronically obstructed airway • characterizations of nppe: acute hypoxemia, upper airway obstruction after removal of endotracheal tube (ett) or laryngeal mask airway (lma), radiographic evidence of pulmonary infiltrates, productive cough of pink frothy sputum • common causes: laryngospasm (50%), upper airway occlusion (11%), residual neuromuscular blockade (nmb) •laryngospasm incidence: 1% of adult general anesthetics, 2% of pediatric cases, 3% in neonates, and up to 10% in the presence of upper respiratory infection or asthma •percent of laryngospasms that result in nppe: 4% • nppe mortality: 5% results/synthesis of evidence • risk factors: age (<35 years), male, asa i-ii classification, reactive airway, active smoking, environmental smoke exposure, lower bmi (<27), ett, and emergency operation • prevention: limited direct laryngoscopy attempts, lma, magnesium sulfate iv for muscle relaxation, adequate and gentle suctioning, deep extubation, oral airway, lidocaine topical or iv, and propofol iv • most common findings: acute and isolated respiratory failure, hypoxemia, productive cough of pink/red frothy sputum, auscultation abnormalities (rales, rhonchi), tachypnea, tachycardia, and paradoxical breathing • diagnostic measures: chest x-ray, arterial blood gas, physical presentation, auscultation abnormalities, bloody bronchoscopy and bronchoalveolar lavage • management: •treating the cause (obstruction) – ppv via facemask, 100% oxygen, adequate nmb reversal, gentle chest compressions (pediatrics), intubation and mechanical ventilation, propofol iv, midazolam iv, succinylcholine iv/im •treating nppe – ppv (bipap, cpap), 100% oxygen, albuterol, diuretic (if no improvement in symptoms), intubation and mechanical ventilation with peep • close monitoring in icu/pacu recommended for 24 hours • average time to full resolution: 30 hours § gaps in the literature: diuretics as treatment, associated surgeries, the the use of desflurane and/or sugammadex as a possible cause negative pressure pulmonary edema christine nagel, bsn, rn, ccrn texas christian university case report pre-anesthetic: • 18 y/o male, 102 kg, pilonidal cyst removal • asa ii – active marijuana smoking • preop vs: 97.6 f, hr 85 bpm, nsr, rr 20 bpm, bp 142/70 intraoperative: • induction: midazolam 2 mg iv, fentanyl 100 mcg iv, lidocaine 50 mg iv, propofol 200 mg iv • muscle relaxation: rocuronium 50 mg iv • ett size 7.5 placed at 21 cm at the teeth • prone position • sevoflurane 2% at 2 l/min used throughout case • neuromuscular reversal: 3/4 twitches, sugammadex 200 mg iv given, 4/4 twitches after reversal postoperative • patient experienced a laryngospasm upon ett removal • oxygen desaturation to 50% • positive pressure ventilation (ppv) and propofol 100 mg iv given with no improvement • succinylcholine 200 mg iv given and patient re-intubated with presence of red, frothy sputum in ett • mechanical ventilation with 100% oxygen given for 20 minutes • furosemide 10 mg iv given for pulmonary edema • patient extubated awake 30 minutes later – placed on 100% oxygen via facemask at 15 l/min • monitored for 24 hours in the pacu • discharged after all symptoms had resolved and pulmonary infiltrates had cleared on the chest x-ray references 1. collins s, schedler p, veasey b, kristofy a. prevention and treatment of laryngospasm in the pediatric patient: a literature review. aana j. 2019;87(2). accessed october 23, 2021. https://www.aana.com/docs/default-source/aana-journal-webdocuments-1/prevention-and-treatment-of-laryngospasm-in-the-pediatric-patient-a-literature-review-april2019.pdf?sfvrsn=de3a986f_8 2. tsai p, wang j, huang s, et al. characterizing post-extubation negative pressure pulmonary edema in the operating room-a retrospective matched case-control study. perioper med. 2018;7(2). accessed october 28, 2021. https://perioperativemedicinejournal.biomedcentral.com/track/pdf/10.1186/s13741-018-0107-6.pdf 3. contou d, voiriot g, djibré m, labbé v, fartoukh m, parrot a. clinical features of patients with diffuse alveolar hemorrhage due to negative-pressure pulmonary edema. lung. 2017;195(4):477-487. accessed october 31, 2021. https://www.proquest.com/docview/1922264919?accountid=7090&forcedol=true&pq-origsite=summon 4. silva la, guedes aa, filho mf, et al. negative pressure pulmonary edema: report of case series and review of literature. rev bras anestesiol. 2019;69(2).222-226. accessed october 30, 2021. https://doi.org/10.1016/j.bjane.2018.12.002 5. furuichi m, shinhiro t, akada s, et al. noninvasive positive pressure ventilation in patients with perioperative negative pressure pulmonary edema. j anesth. 2010;24.464-468. accessed october 30, 2021. https://link.springer.com/content/pdf/10.1007/s00540-010-0899-0.pdf. 6. din-lovinescu c, et al. systematic review of negative pressure pulmonary edema in otolaryngology procedures. ann oto rhinol laryngol. 2021;130(3) 245-253. accessed october 29, 2021. https://journals-sagepubcom.ezproxy.tcu.edu/doi/pdf/10.1177/0003489420938817 7. kao cl, kuo, cy, su yk, hung kc. incidence of negative-pressure pulmonary edema following sugammadex administration during anesthesia emergence: a pilot audit of 27,498 general anesthesia patients and literature review. j clin anesthesia. 2020;62. accessed october 29, 2021. https://www.sciencedirect.com/science/article/abs/pii/s0952818020300015?via%3dihu 8. lemyze m, mallat j. understanding negative pressure pulmonary edema. intensive care med. 2014;40. accessed february 22, 2022. doi: 10.1007/s00134-014-3307-7 9. choi hl, min jh, kang jh, kim h, park js. postobstructive pulmonary edema that developed immediately after emergency surgical cricothyroidotomy. am j emerg med. 2016;34(5):936.e1-936. http://library.tcu.edu/purl/ezproxy_link.asp?/login?url=https://www.proquest.com/scholarly-journals/postobstructivepulmonary-edema-that-developed/docview/1785128652/se-2?accountid=7090. doi: http://dx.doi.org/10.1016/j.ajem.2015.09.018. recommendations and suggestions • careful assessment of risk factors for upper airway obstruction • prevention and treatment preparation in high-risk patients • prevention with gentle suctioning, lma if applicable, oral airway, and proper medications prior to extubation • treatment sequence: 100% + ppv à larson’s maneuver à propofol à succinylcholine à intubation (if unable to ventilate) à peep/ppv à beta-2 agonist àicu/pacu monitoring + 100% oxygen + ppv • non-invasive treatment of nppe was shown to be a safe alternative to intubation and mechanical ventilation • more data and experience with nppe needed to further improve outcomes and patient safety methods § pubmed, pmc, and frog scholar § articles dated between 2010 and 2021 were studied § key words: negative pressure pulmonary edema, signs, symptoms, causes, treatments, prevention, laryngospasm, english-only, meta-analysis, rct, sr § result: pubmed 10, frog scholar 17 § one systematic review (sr), 5 randomized controlled trials (rct), and 1 case series included literature review 1. sr that analyzed the pathophysiology, prevention, and treatment of laryngospasm in pediatric patients to better educate providers in preventing nppe and death. 2. rct that identified the major risk factors of nppe. 3. rct that described the risk factors, features, and outcomes of patients with nppe. 4. case series that identified the causes, risk factors, signs and symptoms, treatments, and preventions of nppe to increase patient safety. 5. rct that tested the effectiveness of nppv compared to invasive ventilation in the treatment of nppe. 6. sr of quasi-experimental studies that identified risk factors, presentation, management, and outcomes of nppe after otolaryngology procedures. 7. rct that examined the correlation between sugammadex and post-extubation nppe on emergence. differential diagnoses: § anaphylactic reaction § cardiogenic pulmonary edema § myocardial infarction § volume overload § pneumonia § pulmonary embolism § aspiration § covid-19 complications risk factors of laryngospasm: age, lower bmi, male, asa i-ii, reactive airway, smoke exposure, ett, emergency operation, multiple dl attempts prevention strategies: • lma versus ett • magnesium sulfate 15-30 mg/kg iv infusion • lidocaine topical or 1-2 mg/kg iv before extubation • sub-hypnotic propofol 0.5 mg/kg iv prior to extubation • thorough suctioning • deep extubation + oral airway treatments: 1. 100% oxygen, ppv, oral airway 2. larson’s maneuver/jaw thrust 3. ensure nmb reversal 4. gentle chest compression (pediatrics) if no ventilation: 1. propofol 0.5 mg/kg iv 2. midazolam 0.03 mg/kg iv 3. succinylcholine 1-2 mg/kg iv or 4 mg/kg im 4. re-intubation + mechanical ventilation symptoms: acute respiratory failure, hypoxemia, productive cough of pink/red frothy sputum, auscultation abnormalities, tachycardia, paradoxical breathing treatments: 1. positive pressure (bipap, cpap) + 100% oxygen a. if re-intubated, give peep 2. beta-2 agonists (albuterol) 3. if no improvement in symptoms, give diuretics nppe prevention/treatment algorithm if laryngospasm occurs: if nppe occurs: figure 2: chest x-ray of bilateral pulmonary infiltrates immediately after nppe occurrence versus follow-up x-ray 24 hours after9 figure 1: pathophysiology of nppe8 texas christian university “the science behind the art” volume 10 no.3 2022 anesthesia ejournal online issn 2333-2611 page 3 protamine reaction in cardiovascular surgery gage walker, bsn, rn, ccrn affiliation: texas christian university grant/financial support: none keywords: protamine reaction, cardiovascular surgery, coronary artery bypass abstract coronary artery bypass grafting is the most performed cardiac surgery throughout the world today. the united states alone performs over 200,000 of these procedures every year. protamine sulfate is administered to neutralize heparin given during these cases. known hemodynamic effects are associated with protamine and on rare occasions, true anaphylaxis. a 10.7% chance exists of a protamine reaction occurring after its administration and five different risk factors that increase that chance is an allergy to fish, use of nph insulins, previous vasectomy, previous exposure to protamine, and rapid administration of protamine. treatment includes fluid resuscitation, administration of vasopressors, intra-aortic balloon pump, and methylene blue but this has not been studied. a heparin removal device as an alternative to protamine shows promise. aej volume 10no. 3 2022 about the author: gage walker is a registered nurse pursuing his doctorate in nurse anesthesia at texas christian university, fort worth, texas. his primary clinical site is in wichita falls, tx texas christian university “the science behind the art” volume 10 no.3 2022 anesthesia ejournal online issn 2333-2611 page 4 powerpoint template ©2009 texas christian university, center for instructional services. for educational use only. content is the property of the presenter and their resources. introduction • cardiopulmonary bypass grafting (cabg) is the most performed cardiac procedure done throughout the world today1 • 10.7% of patients receiving protamine experience a protamine reaction2,3,4 • protamine is administered to neutralize the anticoagulant effects of heparin4 evidence shows that when a reaction does occur, there is an increased mortality risk4 • reactions to protamine can be respiratory in nature such as wheezing, cardiovascular such as hypotension, impaired cardiac output, arrhythmias, pulmonary hypertension, or cardiac arrest, skin such as urticaria, flushing and angioedema, or hematologic such as bleeding3 • protamine is administered routinely in many vascular procedures therefore anesthesia providers should know the risks associated with it and what to do if a reaction occurs • purpose: to discuss known risk factors that precipitate a reaction to protamine, how often a reaction may occur, appropriate treatment for when a reaction does occur, and if there are any alternatives to the administration of protamine available discussion • studies show that suggested treatment is supportive. examples are diphenhydramine 50 mg iv to treat cutaneous manifestations, large volumes of fluid to replace intravascular loss, epinephrine up to 4 mcg/min, dopamine 5 mcg/kg/min, and isoproterenol 2 to 20 mg/min to support cardiac function. intra-aortic balloon pump has also been utilized to support cardiac function2 • methylene blue (500 mg) has successfully treated sustained hypotension after traditional supportive measures were unsuccessful5 • a fixed protamine: heparin ratio dose may be overdosing or underdosing the protamine leading to adverse outcomes6 • a heparin removal device which is an extracorporeal plasmapheresis filter that contains a resin which binds and immobilizes heparin from circulating heparinized blood, was utilized after patient suffered a reaction from protamine and was still bleeding after wound closure. patient was brought back to or and hrd was able to bring act to 160 seconds which was below the baseline of 192 seconds after a 25-minute run time7 • a bovine study demonstrated hrd was able to reverse heparin equal to protamine in an average of 31 minutes compared to a standard 15-minute infusion8 case critique • utilizing a fixed protamine: heparin ratio overdosing the protamine could have led to the reaction6 • the use of methylene blue was a positive, but it could have possibly been administered sooner • a heparin removal device could have been utilized to reverse the heparin lowering the amount of time the patient required cardiopulmonary bypass but as of now it has not received fda approval7 • appropriate utilization of vasopressors and intra-aortic balloon pump to support cardiac function2 • protamine was administered via micro drip over 15 minutes which aligns with research2 protamine reaction in cardiovascular surgery gage walker, bsn, rn, texas christian university figure 1. demonstration of protamine pathophysiology causing hypotension9 case summary • 80-year-old female, 165 cm, 77 kg, scheduled for elective cabg anesthetic evaluation • pmh: cad, htn, mi with stent, ppm due to heart block, gerd, hypothyroid, ddd, parkinson’s disease • labs: na-139, k-4.6, cl-105, co2-28, gap-11, bun-30, crea-0.93, egfr-58, glucose-132, calcium-9.8, alk phos-78, albumin-3.8, wbc-4.7, rbc-4.03, hgb-11.1, hct-35.3, plt-267 • echo: ef 45%, moderate mitral regurgitation, moderate pulmonary hypertension • angiography: left main 70-80% stenosis, rca 80% stenosis, lad 80-90% stenosis • medications: aspirin, omeprazole, potassium chloride, levetiracetam, escitalopram, levothyroxine, metoprolol, calcium carbonate, carbidopa/levodopa, acetaminophen, atorvastatin • psh: cardiac stent placement, hysterectomy • premedication: none • anesthetic plan: geta, a-line and cvl post-induction intraoperative course • monitors applied, preoxygenation • induction: 60 mg propofol, 5 mcg sufentanil, 50 mg lidocaine, 30 mg rocuronium for muscle relaxation • intubation: dl x 1, grade i view, ett 8.0 • maintenance: sevoflurane titrated to effect, ivp sufentanil, vecuronium for muscle relaxation • emergence: postoperative ventilatory support, dexmedetomidine infusion @ 0.5 mcg/kg/hr • severe reaction after administration of protamine with bp dropping as low as 32/17 mmhg • treated with norepinephrine, epinephrine, vasopressin and calcium chloride • methylene blue was administered, and the patient was placed on an iabp • decision: to heparinize again and place the patient back on cpb • once act was 175 seconds, patient was closed and taken to the icu on iabp postoperative course • iabp was discontinued on pod 2. extubated pod 3. oxygen requirements began increasing on pod 8 which required bipap. reintubated and eventually suffered cardiac arrest with cpr initiated and rosc on pod 9. comfort measures were later initiated, and patient passed on pod 9. references 1. roger vl, go as, lloyd-jones dm, et al. heart disease and stroke statistics--2012 update: a report from the american heart association [published correction appears in circulation. 2012 jun 5;125(22):e1002]. circulation. 2012;125(1):e2-e220. doi:10.1161/cir.0b013e31823ac046 2. porsche r, brenner zr. allergy to protamine sulfate. heart & lung. 1999;28(6):418-428 3. weiler jm, gellhaus ma, carter jg, et al. a prospective study of the risk of an immediate adverse reaction to protamine sulfate during cardiopulmonary bypass surgery. j allergy clin immunol. 1990;85(4):713-719. doi:10.1016/0091-6749(90)90189-b 4. nybo m, madsen js. serious anaphylactic reactions due to protamine sulfate: a systematic literature review. basic clin pharmacol toxicol. 2008;103(2):192-196. doi:10.1111/j.1742-7843.2008.00274.x 5. lutjen dl, arndt kl. methylene blue to treat vasoplegia due to a severe protamine reaction: a case report. aana j. 2012;80(3):170-173 6. hecht p, besser m, falter f. 2020. are we able to dose protamine accurately yet? a review of the protamine conundrum. j extra corpor technol. 52(1):63-70. doi:10.1182/ject-1900038 7. conti, v.r., vertrees, r.a., zwischenberger, j.b., kurusz, m., 1995. first clinical use of a heparin removal device: an alternative to protamine. j thorac cardiovasc surg. 109, 1015–1017.. doi:10.1016/s0022-5223(95)70332-2 8. tao w, deyo dj, brunston rl jr, vertrees ra, grochoske tl, zwischenberger jb. efficacy of a heparin removal device in comparison with protamine after hypothermic cardiopulmonary bypass. asaio j. 1997;43(5):m825-m830 9. pearson p, evora p, schaff h, et al. protamine releases endothelium‐derived relaxing factor from systemic arteries: a possible mechanism of hypotension during heparin neutralization. circulation. 1992;86:289-294. recommendations for practice • set guidelines to run protamine over at least a 5–15minute time frame2 • screen all patients who will be given protamine for risk factors of allergy to fish, use of nph insulins, previous vasectomy, and previous exposure to protamine recommendations for future research • further studies on the use of methylene blue to treat hypotension after protamine administration • further studies on the use of a heparin removal device to determine efficacy and appropriateness of its use with known protamine allergies • further studies to assess appropriate dosing of protamine risk factors for a protamine reaction q allergy to fish2 q use of nph insulins2 q previous vasectomy2 q previous exposure to protamine sulfate2 q rapid administration of protamine sulfate2 f supportive evidence • a retrospective analysis by porsche et al assessed incidence and symptoms associated with protamine.2 a reaction occurred between 0.06% and 10.7%.2 different reactions ranged from hypotension, increases in pulmonary artery pressure, bronchospasm, flushing, angioedema, erythema, and pruritus, chills, chest pain, or nausea and vomiting2 • a prospective study by weiler et al examined incidence of protamine reaction.3 248 patients were given protamine, 26 experienced a reaction (10.7%).3 a reaction was considered mild (20-29 mmhg decrease in sbp), moderate (30-49 mmhg decrease in sbp), or severe (50 mmhg decrease in sbp).3 eleven of the reactions were mild, 9 were moderate, and 4 were severe.3 patient risk factors and statistical significance were also significant for t2dm and received protamine-containing insulin3 • a sr by nybo m et al examined incidence of anaphylactic reactions after the administration of protamine sulfate.4 nine retrospective studies found (0.19%) anaphylaxis, 16 prospective studies found anaphylaxis (0.69%).4 prior treatment with nph insulin was the most common predisposing factor to suffer an anaphylactic reaction4 • hecht p et al examined optimal protamine dosing.6 fixed-protamine: heparin ratio dose is one of the most common strategies utilizing 1 mg of protamine for every 100 units of heparin.6 the act-based model is discussed incorporating a mathematical relationship to help determine the appropriate protamine dose based on act levels measured at baseline, before cpb, and pre-protamine as well as initial heparin dose and patient’s weight.6 the act-based model found on average a 40 mg reduction in protamine dose required6 • a randomized controlled trial assessed 12 yorkshire female swine for heparin removal device efficacy compared to protamine administration.8 six were randomly allocated to a protamine group, which were given 1 mg of protamine for every 100 units of heparin and the other 6 were allocated to the heparin removal device group, that had a target of 90% heparin removal.8 no statistically significant changes in hemodynamics were associated with use of the heparin removal device.8 the study found that the heparin removal device was able to reverse systemic heparin anticoagulation by returning pt, aptt, act and heparin concentration to near baseline levels after an average run time of 31.5 minutes8 • a case study by conti et al examined of the first use of a heparin removal device.7 a 44-year-old woman with a history of diabetes that was on nph insulin underwent a cabg.7 a test dose of protamine was given, which resulted in a rapid decrease in sbp from 130 to below 40 mmhg, and an increase in the pap to 52 mmhg, along with right heart failure.7 open cardiac massage and an epinephrine infusion were initiated, and hemodynamics were stabilized after 5 minutes.7 the chest was closed and the patient was taken to the icu with an act of 459 seconds.7 extensive bleeding occurred and the patient was taken back to the or where the decision was made to use a heparin removal device.7 after a run time of 25 minutes the act was 160 seconds, which was below the baseline of 192 seconds7 • a case study by lutjen and arndt examined a 57-year-old woman undergoing a cabg that suffered a protamine reaction. after 80% of the infusion, sbp dropped rapidly from 120 to 62 mmhg, and eventually to as low as 50 mmhg.5 the pap rose from 17/8 mmhg to 28/16 mmhg.5 aggressive treatment with vasopressors, fluids, blood products, and iv steroids maintained sbp between 50 and 60 mmhg.5 methylene blue, 500 mg iv yielded an immediate increase in the sbp to 100 mmhg.5 the operation was completed, and the patient was transferred to the icu in stable condition and discharged 5 days later5 volume 6 no. 2 2018 educated hand publishing llc “the science behind the art” volume 6 no. 2 2018 anesthesia ejournal online issn 2333-2611 page 7 student registered nurse anesthetists: impact of structured high-fidelity simulation on anesthesia ready time michele m. ballister, dnp, crna, aprn, chse affiliation: assistant professor at medical university of south carolina, charleston, sc. funding/conflict of interest disclosure: none keywords: anesthesia, nurse anesthesia, simulation, high-fidelity simulation, anesthesia ready time introduction nurse anesthesia educators are challenged to provide innovative training programs that prepare student registered nurse anesthetists (srnas) to care for a diverse patient population that is living longer with multiple comorbidities.1 use of simulation, including lifelike mannequins, interactive computer programs, and actors role-playing as patients, has gained increasing popularity in health care programs, especially nursing schools, around the world.2 in 2012, 96% of nurse anesthesia programs reported the use of simulation within the curriculum.3 the nurse anesthesia program (nap) at a large academic medical center strives continually to increase the quality of student experiences. in class sizes ranging from 26 to 30 students, srnas complete 12 months of classroom instruction followed by 16 months of clinical training. within that time, each student must complete a certain number of surgical cases plus a required number of specific skills. these cases, required by the council on accreditation of nurse anesthesia programs, involve skills as simple as preparing medications in syringes and as complex as managing a patient with multiple traumatic injuries.4 while the nap program has partnered with many hospitals throughout both south carolina and georgia to provide students the necessary clinical experiences, often these institutions will not accept a student until after the student’s third or fourth month of clinical training. anesthesia department administrators contend that novice srnas slow the fast pace of the operating room (or) because they require too much instruction. unfortunately, this strictly subjective observation greatly limits early student experiences. abstract introduction: student registered nurse anesthetists (srnas) at a large academic medical center are limited in clinical training experiences owing to the subjective perception by local anesthesia department administrators of decreased operating room efficiency with srna involvement. the purpose of this project was to utilize structured high-fidelity simulation (hfs) to increase basic skill proficiency in srnas and evaluate the impact of the simulation within the first month of clinical training. methods: utilizing the iowa model of evidence-based practice to promote quality care, a 5-week structured hfs program was inserted into the nurse anesthesia curriculum before the srnas’ first clinical rotation. the program promoted basic anesthesia skill proficiency through the assimilation of previously taught and tested technical skills. in-room times and anesthesia ready times of all srna cases involving general anesthesia with the placement of an endotracheal tube during september 2012 and 2013 were compiled by use of retrospective chart review. using the calculation of elapsed time between in-room time and anesthesia ready time (irtart), the clinical performance of 2 consecutive classes of srnas was compared, one with structured hfs training and one without. results: the mean irtart for both groups was similar at 20 minutes with a standard deviation of 10 minutes. the irtarts from both groups were within the institution’s operative norm. conclusion: structured hfs did not impact the anesthesia ready time of new-to-practice srnas. however, the information collected during implementation of hfs and data analysis can be used to develop future avenues to improve current processes for structured hfs and clinical training opportunities. aej anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 2 2018 page 8 the anesthesia ready time (art) is a timestamp noted in the electronic health record (ehr) that is used to determine anesthesia efficiency. it is defined as the “time when a surgical patient has a sufficient level of anesthesia established to begin surgical preparation.”5 anesthesia efficiency can be estimated by the elapsed time between art and the time the patient is brought into the surgical suite (in-room time). because a surgery cannot begin until the patient is properly anesthetized, any setback the srna encounters in anesthetizing the patient delays the start of the procedure. many basic anesthesia skills are utilized during the induction sequence of a general anesthetic. an increased proficiency in basic skills can ensure that srna performance does not hinder surgical start times. purpose of the study this project had a dual purpose. the first was to utilize structured high-fidelity simulation (hfs) to increase basic skill proficiency in srnas before the start of clinical training. the second was to evaluate the impact of structured hfs training on the time from in-room time to art (irtart) of srnas during their first month of clinical training. it was hypothesized that structured hfs would improve srna performance and decrease srna irtart. review of the literature an abundance of the literature focuses on simulation in health care education. spanning both quantitative and qualitative designs, examples of the use of simulation include teaching specific tasks, increasing practical knowledge, developing critical thinking skills, increasing student confidence, and decreasing participant anxiety. for this study, evidence of hfs as a teaching tool for foundational skills was examined to include which elements to include as well as examples of implementation of simulation. noted by the institute of medicine as a learning enhancement tool,6 hfs is a training method that exposes srnas to a variety of situations they will face as providers in the or both as trainees and later as crnas. with the use of a computerized mannequin (human patient simulator), a variety of scenarios can be created that offer the srna an opportunity to interact with different patient conditions and to experience surgical situations and complications in real time.7 an ideal environment for experiential learning, hfs offers srnas the opportunity for intervention and reflection to determine what actions are most relevant to clinical practice.8 most importantly, hfs allows for uninhibited student learning without threats to patient safety, threats to quality of care, or fear of blame.9 a 2005 review highlighted 10 essential elements of simulation: feedback, repetitive practice, integration of simulation in curricula, a range of levels of difficulty, multiple learning strategies, a controlled environment, individualized learning, clinical variation, defined outcomes, and simulator validity.10 additional recommendations include a faculty demonstration to visually define the outcomes for participants.11 use of these elements within nursing education varies. a 2010 survey of international nursing association of clinical simulation members noted structural differences in theory utilization, videotaping of sessions, debriefing practices, substitution for clinical time, and equipment.2 the literature does not support a standard theory or framework for integration of simulation within a curriculum nor does it recommend a specific evaluation tool.2 in 2011, meyer et al utilized many of the recommended essentials when implementing simulation into an undergraduate nursing curriculum.12 with scenarios of progressing difficulty, nursing students repeatedly experienced situations and performed skills common in pediatrics.12 simulation-trained students earned higher and more consistent scores on a likert-style tool, leading meyer et al to conclude that student clinical performance was increased as a direct result of simulation.12 this finding suggested positive skill transfer from the simulator to the clinical environment through the use of recommended elements. with the purpose of this study being to improve basic skill proficiency, all the essential elements were incorporated into the simulation program except for varied levels of difficulty. repetition of skills was patterned after meyer’s study and the skills most common within a general anesthetic induction were incorporated. for this study, feedback was defined as immediate debriefing following the completion of a simulation.11 theoretical framework the iowa model of evidence-based practice to promote quality care (iowa model)13 served as the theoretical framework for this study. beginning with the identification of a clinical problem, the model provides a step-by-step guide for implementing change. the model starts with critical questions focused on how the clinical problem impacts the institution and what, if any, foundational research is available. if sufficient evidence exists, the model promotes implementation of change and then evaluation to determine if change is appropriate for adoption into practice. if not, the framework redirects improvement efforts toward soliciting more information or narrowing the initial focus of the clinical problem. the unique questions built into the framework require repeated reflection and review at different stages of the process, thereby keeping the project on target with goals and ensuring orderly completion of necessary steps. answering the questions, in sequence, keeps the project narrowly focused. methods participants after institutional review board approval, this process improvement plan utilized a comparative study design. the intervention group consisted of 10 srna volunteers who had just completed the didactic portion of a front-loaded nurse anesthesia curriculum. the comparison group was the srnas of the prior year who did not receive structured hfs training. the intervention group participants committed to a hfs program that began with orientation to the simulator and viewing a faculty demonstration video. orientation included informed consent, explanation of the purpose of the project, and participant expectations. the video provided a standard of performance and demonstrated the skills that participants would use to successfully negotiate the scenarios. scenarios srnas trained once a week for 5 weeks with the laerdal simman 3g (simman), a high-fidelity computerized interactive mannequin, to assimilate the information taught in prior skill labs to include: anesthesia machine check, medication preparation, airway equipment preparation, and anesthesia induction. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 2 2018 page 9 although the tasks may be considered noncomplex, completing them in succession and in the proper order can be a challenge for novice srnas. the simulation exercises focused on these skills and enhanced performance through repetition. a section of the srna skills laboratory was arranged similarly to an or and included a functional anesthesia machine with ventilator, the mannequin, an operating table, a stocked anesthesia cart, and distilled water for medication simulation. the scenario began with the srna bringing the mannequin to the or and transferring the mannequin to the surgical table and ended when the participant secured the breathing tube. the performance of the srna was immediately analyzed by using both the scenario script and the video recording as references. time was allotted for facilitator-student feedback and questions. all srnas completed the same scenarios, were video recorded, received feedback, and deleted their videos before exiting the simulator. srna performance was not graded as part of the nap curriculum. data collection and analysis participants completed the simulation experience in july 2013. beginning the week of september 1, 2013, participants reported to the or of a level i trauma center for their first month of clinical training. the or had 22 operating suites and offered students experiences in neurosurgery, orthopedics, urology, gynecology, organ transplantation, reconstructive plastic surgery, head and neck surgery, and pediatrics. during 1:1 clinical training with a crna, students completed all the skills reviewed in the simulator course on every general-anesthetic case they participated in. documentation of all or cases, regardless of srna participation, included recording of the in-room time and art. the elapsed time between these 2 points indicated the amount of time it took the anesthesia providers to prepare the patient for surgery and was called the irtart. because these times exist in all or records, we could compare the times for the september 2013 srnas (intervention group) with the september 2012 srnas (control group). the retrospective analysis used information routinely recorded during all surgical cases within the institution’s ehr. the study team utilized the filter and report feature of the ehr to identify srna cases in september 2012 and september 2013. records were filtered for date, srna name, general anesthesia procedures with an endotracheal tube, the in-room time, and the art. the report function of the ehr produced a de-identified spreadsheet that listed the in-room time, art, and the year the procedure was performed. irtart in minutes was calculated from the recorded times. data analysis consisted of a t-test with calculation of the mean and sd of the irtart in minutes by a statistician. results all 10 participants in the intervention group completed the entire simulation program. because of space limitations at the clinical site, 9 students reported to the or at the level i trauma center and completed their first clinical rotation in september 2013. the average age in the intervention group was 28 years (range, 25-31 years), and 7 participants (78%) were female. all of the participants in the intervention group had between 2.5 and 7 years of nursing experience, predominantly in critical care environments. demographic information for the control group was not reported because those srnas were not consented for the project. influential factors outside of the intervention were minimized by comparing the 2 srna classes at the onset of clinical training and in the same clinical site. all raw data points were obtained directly from the ehr. to maintain consistency in comparison, only general anesthesia cases with placement of an endotracheal tube were included in the retrospective chart review. data collection yielded 127 records from september 2012 (control group) and 116 records from september 2013 (intervention group). there was no statistically significant difference in srna performance between the 2 groups. the mean irtart for both groups was 20 minutes with an sd of 10 minutes (p=0.482). therefore, the irtarts of 68% of general anesthesia cases requiring an endotracheal tube involving srnas on their first clinical rotation were between 10 and 30 minutes (table 1). table 1. mean art in minutes by group group no. of records mean art, min sd sem srnas in 2012 127 20.04 10.09 0.90 srnas in 2013a 116 20.10 10.02 0.93 abbreviations: art, anesthesia ready time; hfs, high-fidelity simulation; srna, student registered nurse anesthetist. asrnas in 2013 participated in the structured hfs program. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 2 2018 page 10 discussion the structured hfs scenarios were designed to increase srna basic anesthesia skills with the intent that students would require less step-by-step instruction during their first clinical rotation. the program aimed to provide participants with a systematic approach to induction of general anesthesia that could be augmented for specific procedures when necessary in the clinical environment. this was accomplished by using scenarios with 5 different surgical procedures commonly encountered by new srnas. all 5 cases were nonemergent procedures for healthy patients and required the same anesthesia induction plan. the srna control group did not receive structured hfs training. hfs was available to them but it was not mandated nor was it highly structured. for example, an afternoon skills lab included multiple stations and students self-selected the amount of time spent with each skill. hfs experiences varied, the simulations lacked objectives, and scenarios were dependent on the instructors. there was no standard amount of time the students spent in hfs and participation required self-motivation. the project’s orientation process provided the intervention group with a standard of performance for the basic skills of equipment preparation, medication preparation, and the steps of anesthesia induction. while provider skill level is an element, many other things influence the amount of time required to safely anesthetize a patient, such as the surgical procedure; the patient’s size, age, and weight; and the need for an endotracheal tube and any additional intravenous, arterial, or central access or monitoring devices. all of these factors and tasks can impact the time anesthesia providers require to anesthetize a patient.14 no benchmarks exist within the literature or anesthesia professional organizations that state what an irtart should be for a specific surgical procedure, diagnosis, or presenting patient condition.14 this simulation program does not account for every situation or factor that may impact an irtart but promotes repetition of the portions of an anesthetic that are within the provider’s control, such as ensuring the presence and function of airway equipment. therefore, the percentage of srnas with irtart beyond 30 minutes may have experienced a delay related to something other than their basic skill level. this cannot be determined without additional data collection. the medical center’s or surgical schedule begins at 0730 every weekday. for a procedure scheduled to start at 0730, the anesthesia provider is expected to bring the patient to the assigned or suite by 0700, allowing approximately 30 minutes for the induction of anesthesia. the clinical performance of both groups of nurse anesthesia students, those with and without structured hfs before the onset of clinical training fell within the scheduled 30-minute time frame. while an impact of structured hfs was not seen with the comparison of irtarts, the data and statistical analysis highlight the positive performance of the majority of students within the institution’s established acceptable time frame for the anesthetic preparation of a patient. the results of this project support 3 main conclusions. first, the current nap curriculum prepares students to perform within this or’s accepted time frame of efficiency at the start of their clinical training. this is highlighted by the very similar performance of both groups during the first month of their initial or rotation. second, the art did not indicate an effect of structured hfs on the training of nurse anesthetists. it is possible that both groups performed equally because the hfs training did not have an impact or that art is not sensitive to differences in individual performance. a larger sample size or a different measurement tool may better identify changes in student proficiency as a result of hfs. third, the 2 years of consistent average arts between 10 and 30 minutes can be used to partially counter the argument that novice nurse anesthesia students decrease or efficiency. the presence of basic skills on arrival to the clinical setting allows preceptors to tailor training to other factors that impact timely performance. in summary, nap students have limited clinical training opportunities as a result of unconfirmed observations of anesthesia department administrators that srnas decrease or efficiency because they require too much instruction. guided by the iowa model, we inserted a 5-week, structured hfs program into the nap curriculum before the students’ first clinical rotation. the program promoted basic anesthesia skill proficiency through the assimilation of previously taught and tested technical skills. using the calculation of irtart, we compared the clinical performance of srnas who underwent the structured hfs training with that of srnas with unstructured hfs training. in conclusion, the structured hfs did not impact the art of new-to-practice srnas, although the irtarts of both groups were similar and within the institution’s operating norms. the information gained during the implementation of hfs and the data analysis period can be used to develop future avenues to improve current processes. further studies identifying clinical indicators sensitive to hfs are necessary before cause and effect can be determined. acknowledgement: special thanks to angela mund, dnp, crna, dorothy coley, mhs, crna, raymon white, msna, crna, andrea iksic, msna, cnra and patricia aysse, msn, rn for your effort and dedication to this project. i would also like to sincerely thank debra shearer, edd, msn, fnp-bc, bernard gilligan, dnp, crna, andy battacharya, mhs and the dnp faculty at villanova university for their guidance and support of this project. anesthesia ejournal www.anesthesiaejournal.com volume 6 no. 2 2018 page 11 references 1. harder bn. use of simulation in teaching and learning in health sciences: a systematic review. j nurs educ. 2010;49(1):2328. https://doi.org/10.3928/01484834-20090828-08. 2. gore t, van gele p, ravert p, mabire ca. 2010 survey of the inacsl membership about simulation use. clin simul nurs. 2012;8(4):e125-e133. https://doi.org/10.1016/j.ecns.2012.01.002. 3. cannon-diehl mr, rugari sm, jones ts. high-fidelity simulation for continuing education in nurse anesthesia. aana j. 2012;80(3):191-196. 4. council on accreditation of nurse anesthesia programs. accreditation standards, policies and procedures, and guidelines website. standards for accreditation of nurse anesthesia programs. practice doctorate. http://home.coa.us.com/ accreditation/documents/standards%20for%20accreditation%20of%20nurse%20anesthesia%20programs%20-%20 practice%20doctorate,%20rev%20june%202016.pdf. accessed july 7, 2017. 5. zafar su, khan fa, khan m. standardization of anesthesia ready time and reasons of delay in induction of anesthesia. j pak med assoc. 2006;56(3):112-115. 6. dracup k. nursing education: recommendations for the future. in: institute of medicine (us) committee on the robert wood johnson foundation initiative on the future of nursing. the future of nursing: leading change, advancing health. washington, dc: national academies press (us); 2011:516-525. 7. nehring wm, ellis we, lashley fr. human patient simulators in nursing education: an overview. simul gaming. 2001;32(2):194-204. https://doi.org/10.1177/104687810103200207. 8 detty-oswaks js. the use of simulated clinical experiences to improve competency in the novice anesthesia provider [dissertation]. memphis: university of tennessee; 2002. retrieved from proquest dissertations and thesis database (umi no. 3067791). 9. schwid ha, rooke ga, carline j, et al; anesthesia simulator research consortium. evaluation of anesthesia residents using mannequin-based simulation. anesthesiology. 2002;97(6):1434-1444. https://doi.org/10.1097/00000542-200212000-00015. 10. issenberg sb, mcgghie wc, petrusa er, gordon dl, ross rj. features and uses of high-fidelity medical simulations that lead to effective learning: a beme systematic review. med teach. 2005;27:1,10-28. https://doi. org/10.1080/10421590500046924. 11. cantrell ma. the importance of debriefing in clinical simulations. clin simul nurs. 2008;4(2):e19-e23. https://doi. org/10.1016/j.ecns.2008.06.006. 12. meyer mn, connors h, hou q, gajewski b. the effect of simulation on clinical performance. simul healthc. 2011;6(5):269277. https://doi.org/10.1097/sih.0b013e318223a048. 13. titler mg, keliber c, steelman v, et al. the iowa model of evidence-based practice to promote quality care. crit care nurs clin north am. 2001;13:497-509. 14. maheshwari k, you j, cummings kc iii, et al. attempted development of a tool to predict anesthesia preparation time from patient-related and procedure-related characteristics. anesth analg. 2017;125(2):580-592. https://doi.org/10.1213/ ane.0000000000002018. https://doi.org/10.3928/01484834-20090828-08 https://doi.org/10.1016/j.ecns.2012.01.002 http://home.coa.us.com/accreditation/documents/standards%20for%20accreditation%20of%20nurse%20anesthesia%20programs%20-%20practice%20doctorate,%20rev%20june%202016.pdf http://home.coa.us.com/accreditation/documents/standards%20for%20accreditation%20of%20nurse%20anesthesia%20programs%20-%20practice%20doctorate,%20rev%20june%202016.pdf http://home.coa.us.com/accreditation/documents/standards%20for%20accreditation%20of%20nurse%20anesthesia%20programs%20-%20practice%20doctorate,%20rev%20june%202016.pdf https://doi.org/10.1177/104687810103200207 https://doi.org/10.1097/00000542-200212000-00015 https://doi.org/10.1080/10421590500046924 https://doi.org/10.1080/10421590500046924 https://doi.org/10.1016/j.ecns.2008.06.006 https://doi.org/10.1016/j.ecns.2008.06.006 https://doi.org/10.1097/sih.0b013e318223a048 https://doi.org/10.1213/ane.0000000000002018 https://doi.org/10.1213/ane.0000000000002018 volume 9no. 9 2021 educated hand publishing llc “the science behind the art” volume 9 no.9 2021 anesthesia ejournal online issn 2333-2611 page 17 off-label rescue agents for vasoplegic syndrome after cardiopulmonary bypass jessica gatehouse, bsn, rn, ccrn affiliation: texas christian university grant/financial support: none keywords: methylene blue, vasoplegia, cardiopulmonary bypass, cardiac surgery, hydroxocobalamin abstract cardiovascular disease is the number one cause of death in the united states today1. cardiopulmonary bypass (cpb) is a common technique used in the surgical management of cardiovascular disease. a relatively common complication of cpb is vasoplegia, which has an approximate incidence of anywhere from 5-25%1-8. methylene blue is used to treat vasoplegic syndrome (vs) when higher dose vasopressors are ineffective. vasoplegic syndrome (vs) is defined as a syndrome of low systemic vascular resistance (svr) in the presence of normal or high cardiac output1-4. generally, vs is characterized as a high cardiac output state (ci < 2.2 l/min/m2) with difficulty maintaining a mean arterial pressure (map) greater than 60 mmhg despite increasing vasopressor requirements1-3,7. the focus of this case report is to examine methylene blue’s effectiveness in treating vasoplegia after weaning from cpb. this case report will also compare and contrast methylene blue and another rescue agent, hydroxocobalamin, and how they combat vasoplegia. aej volume 10 no. 1 2022 educated hand publishing llc “the science behind the art” volume 10 no.1 2022 anesthesia ejournal online issn 2333-2611 page 1 use of a high-fidelity patient simulator to introduce an evidence-based emergency manual into certified registered nurse anesthetist practice ltc james b. hacker, dnap, crna, an, usa1 ltc(p) paul m. johnson, dnp, crna, chse, an, usa1,2 ltc(ret) sandra s. bruner, dnap, crna 1,2 capt justice parrott, dnap, crna, nc, usn2 lt col katherine j. alguire, dnap, crna, nc, usaf2 lcdr tiffany ann uranga, dnp, msn, crna, nc, usn2 sunny jade yauger, bs, chse1 col ann nayback-beebe, phd, fnp, an, usa3 affiliation: 1fort belvoir community hospital, fort belvoir, virginia 2daniel k. inouye graduate school of nursing registered nurse anesthesia program, uniformed services university of the health sciences, bethesda, maryland 3walter reed national military medical center, bethesda, maryland grant/financial support: none keywords: high-fidelity simulation, anesthesia, critical events, crnas, emergency abstract certified registered nurse anesthetists (crnas) administer anesthesia care to thousands of patients each year. despite increased anesthetic safety, low-frequency, high-risk perioperative critical events still occur. although crnas have been expected to rely on memory alone to manage the spectrum of these critical events, the use of an emergency manual (em) may improve crna performance. recent experiences with similar critical events at one army community hospital led to the development of the following question: will the use of high-fidelity simulation training with the crnas on the use of ems produce both increased performance in key tasks and positive satisfaction scores related to the use of the emergency manual during critical events now and in the future? twenty crnas participated in highfidelity simulated scenarios involving low-frequency, high-risk critical events before and after training on the use of an em based on a change strategy developed by goldhaber-fiebert and howard in 2012. changes in performance after training were evaluated using a tool designed by arriaga et al. before em training, crnas completed 46.05% of key tasks in the simulated scenario. after em training, crnas completed up to 94.02% of key tasks in simulated scenarios. the increased completion of key tasks by crnas during simulated critical events after em training and increased satisfaction scores. these results demonstrate how a well-constructed training program facilitates implementation of an evidence-based em into practice. aej educated hand publishing llc “the science behind the art” volume 10 no.1 2022 anesthesia ejournal online issn 2333-2611 page 2 introduction certified registered nurse anesthetists (crnas) provide anesthesia for thousands of patients annually. despite their qualifications and skills, which have drastically reduced the morbidity and mortality of patients under anesthesia, lowfrequency, high-risk perioperative critical events still occur, including sudden cardiac arrhythmia, airway fire, anaphylaxis, hemorrhage, local anesthetic toxicity, and embolism.1 the overall incidence of perioperative critical events has been estimated at 145 events per year for a hospital that performs 10,000 operations.2,3 thus, critical events may be so rare that individual anesthesia providers never experience them in practice, preventing opportunities to form pattern recognition, which is a key characteristic of expert clinical decision-making.4 crnas are expected to rely on memory alone to recall key actions and seamlessly manage a wide array of critical events, therefore, mismanagement or deviation from accepted practice due to human error, may account for a substantive portion of anesthesiarelated risk.5 utilization of an emergency manual (em) can increase the number of key actions completed by anesthesia providers during low-frequency, high-risk perioperative critical events.6-10 in 1924, babcock expressed if a critical event during surgery required a response that was not instantly obtained by simple measures, a fixed emergency routine should be posted on the walls of every operating room, drilled into every staff member, and strictly enforced.11 over 90 years later, there remains a cultural reluctance among anesthesia providers towards use of emergency checklists during perioperative critical events, with one study reporting 60% of anesthesia residents believing they should be able to manage a critical event from memory alone.6 substantial evidence indicates anesthesia providers routinely do not remember all actions involved in managing emergent events from memory alone.12 indeed, three recent editorials make the same plea as babcock did in 1924, concluding it is time to adopt the use of emergency routines during the perioperative period.11 several studies demonstrate healthcare providers perform poorly when relying solely on memory to manage simulated critical events.8,13-16 for instance, smith et al found a rapid decline in advanced cardiac life support (acls) skills among nurses after 3 and 12 months post-training, (30% and 14% of nurses, respectively).13 similarly, 6 months after advanced life support training, semeraro et al found a 36% reduction in the number of anesthesiologists who passed a multiple-choice test, a 1-min increased time to first defibrillation, and other delayed or forgotten interventions.14 berkenstadt et al reported a decay in knowledge and skills during simulated cardiac arrest in obstetric patients, with only 0–4% of anesthesia providers removing fetal monitors, 44–68% positioning the patient with left uterine displacement, 48–78% maintaining cricoid pressure during ventilation, and 40–83% delivering the fetus by caesarean in 5 min or less.15 henrichs et al found that although anesthesiologists performed better than crnas in eight simulated perioperative critical events, both groups performed poorly overall, completing only 66.6% and 59.9% of key tasks, respectively.16 in a simulated malignant hyperthermia scenario, harrison et al found that not all teams needed a cognitive aid to perform well. however, the teams that performed well often used an aid, whereas the teams that performed the most poorly did not use an aid.8 it may be impossible to prospectively determine whether a team will perform well in a crisis situation but may be prudent to train all teams on the use of cognitive aids and ensure aids are readily available during unfamiliar or life-threatening situations. picot question & model the target institution for this project performed approximately 10,000 operations per year.  in 2014-2015, there were several incidents of low-frequency, high-risk, critical events that challenged anesthesia providers to make accurate, evidence-based decisions while under a high level of stress and during hours when additional staff may not be available. as a countermeasure to these situations, our team developed the following picot question: would the use of high-fidelity simulation training using ems conducted over one week with practicing crnas produce both increased performance in key tasks and positive satisfaction scores related to the use of the emergency manual during critical events now and in the future? the change strategy adopted for this project developed by goldhaber-fiebert and howard called for a four-step process to achieve success within an institution when implementing an em.17 the first step was to create or adapt an em on the local level to meet the specific needs of the institution. second, training was incorporated to increase crna familiarity with the em. third, it was ensured that the em was accessible and effectively used. finally, integrating the em was integrated as a part of the institution’s quality and safety culture. utilizing this strategy and adapting it to the specific constraints of our facility, our team sustained a change in practice among our anesthesia providers and better outcomes for our patients when faced with critical events. training program after receiving exempt status from the institutional review board, the project was conducted at an army community hospital over a 5-day period in april 2017. data collection and training were carried out in a manner similar to that described by goldhaber-fiebert et al.9 twenty crnas were divided into teams of two, and pre-training data collection, training, and posttraining data collection and subjective evaluation were completed within a 150-min session. for pre-training data collection, the number of key tasks completed by groups were counted during a high-fidelity simulation of a perioperative critical event (eg, anaphylaxis). crnas were then trained on the use of the selected em through a trigger film on severe bradycardia. the em chosen for this project was the stanford emergency manual version 3.1 that included validated algorithms for twentyfive different perioperative emergencies and anesthesia crisis resource management (acrm) resources.18 for post-training data collection, crnas used the em during two additional simulations of perioperative critical events (eg, intraoperative hemorrhage and ventricular fibrillation/cardiac arrest), and the numbers of key tasks completed were counted. for each simulation, one crna served as the primary provider or “leader”, and the other served as the emergency consult or “reader”. the educated hand publishing llc “the science behind the art” volume 10 no.1 2022 anesthesia ejournal online issn 2333-2611 page 3 simulations were conducted as described by arriaga et al and video-recorded for data collection purposes.19 the simulated critical events were conducted using the human patient simulator (hps) with optional hps equipment (cae healthcare). the hps is the only human patient simulator that supported the modeling of potent inhalational anesthetics and exchanges oxygen and carbon dioxide gases to replicate patient physiology,20 and it also integrated with clinical monitoring equipment. the hps allows crnas to administer medications, indicated or contraindicated, during the scenario, with a subsequent automatic natural physiologic response. in essence, the hps replicates human physiology in a response manner analogous to real patients enhancing the fidelity of the simulation experience. the effectiveness of the training was assessed by tallying the proportion of key tasks completed during the post-training scenarios. each simulated critical event was evaluated by two project team members who observed the scenarios in real time. in cases of discrepancy between team members, the video recording was used to confirm the observations. crnas’ perceptions of the usefulness and clinical relevance of the em were assessed using a questionnaire immediately after completing the first (eg, pre-training) and third (eg, post-training) scenarios to evaluate likelihood of adopting the em in future practice. crnas were additionally surveyed to assess opinions on the quality of the overall session, em checklists, and scenarios. training results twenty crnas participated in the three high-fidelity simulated critical events; one scenario was delivered before em training, and two scenarios were delivered after em training. in the first scenario (anaphylaxis), crnas completed 46.05% of key tasks on average without em use (figure 1). the most common missed actions included failing to call for the code cart, continuing a volatile agent, not considering additional intravenous access, not administering a histamine-2 receptor antagonist, and not performing five additional actions related to post-anaphylaxis care and referrals. in the second scenario (hemorrhage), crnas completed 80.56% of key tasks on average while using the em. the most common missed actions included failing to call for the code cart, not placing the patient in trendelenburg position, not confirming or placing a foley catheter, and failing to call for the cell saver system. in the third scenario (ventricular fibrillation), crnas completed 94.02% of key tasks on average while using the em. no major key actions were missed, with the exception of one instance of failing to consider antiarrhythmic medications. administration of magnesium sulfate for torsade de pointes, and concurrent administration of calcium chloride, insulin, glucose, and sodium bicarbonate for hyperkalemia, were omitted as key actions because this scenario did not include either condition as a potential cause of ventricular fibrillation. a questionnaire was provided to participating crnas after the first pre-training and third post-training scenarios (table 1). the greatest change in score was for crnas’ perception that they learned something new (+0.92) and feeling that they did things during the training day they never would have been able to practice otherwise (+0.64). the vast majority of crnas (98.8%) believed that em use supported safer care and allowed them to be better prepared when confronted with anesthesia-related crises. crnas also believed that all operating room staff should be trained on em use (97.8%), that the em did not hinder clinical flow (97.8%), and that they would want the em used if they were the patient (97.8%). after the session, crnas were asked additional questions about the quality of the overall session, em checklists, and scenarios; willingness to repeat the simulations and attend training again if it were provided off-site; feelings of overall stress while using the em; and intention to use what was learned in future practice. crnas were also asked where in the operating room they felt would be most appropriate to place the em after being fully implemented into local practice. crnas expressed satisfaction with the quality of the simulation, em checklists, and scenarios. crnas also expressed an unwillingness to attend off-site trainings and general feelings of less stress when using the em. the majority of crnas (71%) wanted the em placed on the wall in the operating room in clear view using a document holder. discussion consistent with the findings of goldhaber-fiebert et al and arriaga et al, the authors observed em training increased the proportion of key tasks completed during simulated critical events, from 46.05% after the first scenario to 94.04% after the final scenario.9,10 this analysis was limited by the design of the training session and the small number of crnas completing the training. the large change in task completion rate led the authors to believe future implementation of the em into crna practice at other facilities could yield significant improvements in response to low-frequency, high-risk perioperative critical events. full implementation of em training and practice among all anesthesia providers and operating room staff should be considered. it must be noted that the design of this project was intended to deliver the most complete training experience for the crnas by having them participate in all three clinical scenarios. formal statistical analysis was not applied due to the lack of controls between scenarios or for repeated training effect. regardless of these issues, the drastic change in key task performance proved invaluable when demonstrating the importance of using an em for the management of critical anesthesia events. types of emergent high-fidelity simulation scenarios, selected for this project, produced some unexpected patterns of performance. the first scenario (anaphylaxis) yielded an appropriate acute response for all crnas involved (ie, call for help, increase fio2, epinephrine or albuterol administration), overall rates of task completion ranged between 80–100%. weaknesses in performance were observed in post-acute event care, including failure to administer histamine-2 antagonists and/or steroids, perform laboratory evaluation, consult the allergy service, and continue further observation, with completion rates ranging between 0–50%. such weaknesses in post-acute event performance highlighted the need for crnas to use a cognitive aid, such as an em. the hemorrhage management noted deficiencies in four key tasks: calling for a code cart, placing the patient in trendelenburg position, placing a foley catheter, and calling for a cell saver system. the participants indicated they would have called for the educated hand publishing llc “the science behind the art” volume 10 no.1 2022 anesthesia ejournal online issn 2333-2611 page 4 code cart if the scenario had been perceived as leading to cardiac arrest as opposed to an isolated massive resuscitation effort. trendelenburg positioning was frequently not considered in lieu of focusing on other key actions. in some cases, pre-placement of a foley catheter was assumed due to the nature of the open abdominal surgery scenario, and cell saver capability was not available at the location where training was taking place. these shortfalls highlighted the need to tailor the scenarios and em to increase relevance to the practice setting. more thorough briefing to address scenario key factors would have added clarity. the ventricular fibrillation scenario demonstrated the highest levels of performance. no specific deficiencies were noted. whether this improvement in performance across the three scenarios is the result of greater training effect within the simulation exercises and use of the em, or experience and comfort in managing certain types of critical events, was difficult to ascertain within the scope of this project. however, this issue pointed toward potential areas for future research on training crnas to respond to critical events. furthermore, it could have been possible that the highest rates of completion of key tasks in the ventricular fibrillation scenario were related to the frequency of training received on this event through acls recertification every two years. conclusion utilizing an em during simulated critical events can increase the completion of key tasks by crnas, thereby enhancing the quality of care delivered to patients during perioperative critical events. feedback shows positive trends that the training was perceived as both valuable and well-constructed. these findings are encouraging and justify expansion and inclusion of similar simulation-based em training to include all disciplines of the perioperative healthcare team. furthermore, widespread implementation of similar simulation-based training programs and ensuring the availability of ems should be encouraged throughout all training and patient care arenas. the use of standardized ems is relatively new within medical and nursing disciplines, and the best method of implementation is yet to be determined. however, with proper training, ems have the potential to make a positive, enduring impact on care provided during low-frequency, high-risk critical events.21 summary of key points • cognitive aids in the form of emergency manuals have been shown to increase the performance of individuals and teams when faced with low-frequency, high-risk, critical events. despite this evidence, culture within many medical disciplines still endorses working from memory alone. • some low-frequency, high risk, critical events are so rare that a provider may not encounter them throughout their career. • memory degrades over time and as such performance degrades as well. this is demonstrated by studies that have investigated the performance of practitioners in cardiac arrest management at after training. at six to nine months after training, most practitioners would fail a basic life support or advanced cardiac life support test if taken without refreshments of knowledge and skills. • the use of high-fidelity simulation provides a realistic platform for institutions to implement and sustain the use of an emergency manuals. examination of the providers improved performance using the manual without patient risk can be convincing even to providers with the long-held belief that they need to remember everything. • emergency manuals when coupled with proper team dynamics such have the potential to greatly enhance patient outcomes to low-frequency, high-risk, perioperative critical events. references 1. hogan p, seifert rf, moore cs, simonson be. cost effectiveness analysis of anesthesia providers. nursing economic$. june 2010;28(3):159-169. 2. webb rk, currie m, morgan ca, et al. the australian incident monitoring study: an analysis of 2000 incident reports. anaesthesia and intensive care. 1993;21(5):520-528. 3. charuluxananan s, punjasawadwong y, suraseranivongse s, et al. the thai anesthesia incidents study (thai study) of anesthetic outcomes. journal of the medical association of thailand=chotmaihet thangphaet. 2005;88:s14-s29. 4. o’neill es, dluhy nm, chin e. modeling novice clinical reasoning for computerized decision support system. journal of advanced nursing. 2005;49(1):68-77 5. diehl mr, sanders kk. anesthesia complications. in: nagelhout jj, plaus kl eds. nurse anesthesia. 5th ed st louis, mo: elsevier saunders; 2014:1289-1308. 6. neal jm, hsuing rl, mulroy mf, halpern bb, dragnich ad, slee a. asra checklist improves trainee performance during a simulated episode of local anesthetic toxicity. regional anesthesia and pain medicine. 2012;37(1):8-15. 7. augostides jg, atkins j, kofke wa. much ado about checklists. anesthesia & analgesia. 2013;117(5):1037-1038. 8. harrison tk, manser t, howard sk, gaba dm. use of cognitive aids in a simulated anesthetic crisis. anesthesia & analgesia. 2006;103(3):551-556. 9. goldhaber-fiebert s, lei v, nandagopal k, bereknyei s. emergency manual implementation: can brief simulation-based or staff trainings increase familiarity and planned clinical use? the joint commission journal on quality and patient safety. may 2015;41(5):212-220. 10. arriaga af, bader am, wong jm, et al. simulation-based trail of surgical crisis checklists. new england journal of medicine. january 2013;368(3):246-253. 11. babcock ww. resuscitation during anesthesia. anesthesia & analgesia. 1924;3(6):208-213. http://journals.lww.com/ anesthesia-analgesia/citation/1924/12000/ resuscitation_during_anesthesia_.3.aspx. accessed december 10, 2016. 12. stiegler mp, neelankavil jp, canales c, dhillon a. cognitive errors detected in anesthesiology. british journal of anesthesiology. 2012;108(2):229-235. 13. smith k, gilcreast d, pierce k. evaluation of staff ’s retention of acls and bls skills. resuscitation. 2008;78:59-65. 14. semeraro f, signore l, cerchiari el. retention of cpr performance in anaesthetists. resuscitation. 2006;68:101-108. 15. berkenstadt h, ben-menachem e, dach r, et al. deficits in the provision of cardiopulmonary resuscitation during simulated obstetric crises: results from the israeli board of anesthesiologists. anesthesia & analgesia. 2012;115(5):112-1126. 16. henrichs bm, avidan ms, murray dj, et al. performance of certified registered nurse anesthetists and anesthesiologists in a simulation-based skills assessment. anesthesia & analgesia. 2009;108(1):255-262. 17. goldhaber-fiebert sn, howard sk. implementing emergency manuals: can cognitive aids help translate best practices for patient care during acute events? anesthesia & analgesia. 2013;117(5):1149-1161. 18. stanford anesthesia cognitive aid group. emergency manual: cognitive aids for perioperative clinical events. creative commons by-nc-nd; 2016. http://emergencymanual.stanford.edu. updated 2016. accessed october, 2016. 19. arriaga af, bader am, wong jm, et al. simulation-based trial of surgical crisis checklists. new england journal of medicine. 2013;368(3 suppl.). 20. human patient simulator (hps): physiology you can count on. cae healthcare. http://www.caehealthcare.com/images/ uploads/brochures/hps.pdf. published 2015. accessed january 5, 2017. 21. morrell rc, cooper jb. apsf sponsors workshop in implementing emergency manuals. apsf newsletter. february 2016;30(3):68-71. educated hand publishing llc “the science behind the art” volume 10 no.1 2022 anesthesia ejournal online issn 2333-2611 page 5 http://journals.lww.com/anesthesia-analgesia/citation/1924/12000/ http://journals.lww.com/anesthesia-analgesia/citation/1924/12000/ http://emergencymanual.stanford.edu http://www.caehealthcare.com/images/uploads/brochures/hps.pdf http://www.caehealthcare.com/images/uploads/brochures/hps.pdf figure 1. percentage of key tasks completed during simulated critical event scenarios before and after em training. educated hand publishing llc “the science behind the art” volume 10 no.1 2022 anesthesia ejournal online issn 2333-2611 page 6 table 1. crna perceptions before and after em training. average scores question before em after em score difference the scenario was realistic. 4.75 4.89 4.89 the scenario was appropriately challenging. 4.55 5.00 +0.45 this scenario will help me provide safer patient care. 4.65 4.94 +0.29 this scenario prompted realistic response from me. 4.58 4.83 +0.25 i felt i did things during this training day that i never would have had a chance to practice otherwise 3.80 4.44 +0.64 the knowledge gained will be helpful to me in my practice. 4.60 4.89 +0.29 i enjoyed the training session. 4.75 4.94 +0.19 i learned something new. 3.75 4.67 +0.92 this training session should be taken by all or staff 4.50 4.89 +0.39 1=strongly disagree, 2=slightly disagree, 3=neutral, 4=slightly agree, 5=strongly agree. the questionnaire was adapted from that used by arriaga et al.19 educated hand publishing llc “the science behind the art” volume 10 no.1 2022 anesthesia ejournal online issn 2333-2611 page 7 texas christian university “the science behind the art” volume 11 no.1, 2023 anesthesia ejournal online issn 2333-2611 page 1 a review evaluating intravascular access for high volume resuscitation: can you keep up? puneet mishra, md • puneet.mishra@vumc.org jonathan p. wanderer, md • jon.wanderer@vumc.org david a. edwards, md • david.a.edwards@vumc.org susan s. eagle, md • susan.eagle@vumc.org stephen p. bruehl, phd • stephen.bruehl@vumc.org matthew w. semler, md • matthew.w.semler@vumc.org kelly l. mishra, md • kelly.mishra@vumc.org acknowledgments: caroline walker (msn) assisted with infographic editing. cassandra palmer (bs) assisted with infographic editing. disclosures: no financial support or funding was provided for this work declaration of conflicting interests: no conflicts of interest to declare. affiliation: vanderbilt university medical center keywords: vascular access devices, resuscitation, central venous catheterization, peripheral venous catheterization, hypovolemia abstract anesthetists and anesthesiologists are frequently in the position of administering high-volume resuscitation in the setting of hemorrhage, hypovolemia, or vasodilatory shock. the ability to rapidly infuse intravenous (iv) fluid solutions differs vastly for different types and sizes of iv access. in patients who may require rapid large volume resuscitation, it is critical to understand the capacity of existing iv devices. selecting the most appropriate iv access for patients can be paramount in preventing hypotension, end organ dysfunction, and even death. this article objectively reviews and compares the flow rates of commonly used central and peripheral intravenous devices to demonstrate the influence of catheter length and radius. aej volume 11no. 1, 2023 glossary of terms: iv = intravenous ml/min = milliliters/minute q = flow rate n = viscosity r = radius l = length of tubing pivs = peripheral intravenous catheters piccs = peripherally inserted central catheters cvcs = central venous catheters rics = rapid infusion catheters io = intraosseous mac = arrow® multi-lumen access catheter fr = french lad = luer activating devices slic = single lumen infusion catheter introduction choosing the most appropriate vascular access in patients with hypovolemic or vasodilatory shock is a critical decision for a perioperative or critical care clinician. while this is seemingly simple, a clinician must weigh the adequacy of existing intravenous (iv) access versus the time needed to place additional large-bore peripheral or central catheters. this is particularly critical in the time sensitive setting of acute hypovolemic shock due to severe hemorrhage in the perioperative and obstetrical arenas, where acute bleeding at rates over 500ml/min can occur.1 different forms of iv access have drastic differences in their ability to facilitate rapid fluid resuscitation ranging from maximum flow rates of 9.6 milliliters/minute (ml/min) to over 500ml/min. this manuscript collates information on several of the most common iv devices and presents it in tabulated and graphical format for easy reference. this information is meant to provide clinical decision support to the perioperative and critical care clinician. discussion intravenous flow rates the fundamental principles of poiseuille’s law (q = πpr4/8nl) is critical in understanding the relationship among catheter length, radius, and flow rates for laminar flow. poiseuille’s law states that flow rate (q) is proportional to the pressure gradient along the iv tubing and inversely proportional to the viscosity (n) of the fluid as well as the length of the tubing (l ). increased fluid viscosity and increased length of tubing result in decreased flow rate when pressure is held constant. very importantly, q is proportional to the iv catheter radius (r) to the fourth power. therefore, increasing the radius of an iv catheter drastically increases and has the largest impact on the flow rate. the impact of changes in r and l on q, account for the wide range of flow rates across iv devices. this concept is paramount for understanding why some forms of central access may be superior while other are inferior to peripheral access when rapid, high-volume resuscitation is warranted. the infographic in figure 1 compares the flow rates of these iv catheters. although the radius and length of iv catheters are of critical importance, there are numerous other factors that can affect flow rates. these include viscosity of the fluid administered, the radius of delivery tubing, the height of the fluid above the patient, the addition of a pressure bag, the presence of a fluid warmer, and in line devices such as luer-activating devices (lads) with one-way valves that can limit flow. for example, lads can reduce the flow rates through a 16g piv by 19-38%.2 placing a pa catheter or arrow® single lumen infusion catheter (slic) through the introducer port on an arrow® multi-lumen access catheter or an arrow® 8.5 fr introducer will also reduce the flow rate. this explains why there are certain clinical scenarios where the maximum flow rate may be less than the manufacturer published rates.3,4 however, the general principles of poiseuille’s law still apply, and the comparison between the different devices remains constant. types of intravenous access choosing the most appropriate iv access requires consideration of many factors, such as the specific indication for placement, the length of time the access will be required, how quickly access is needed, medications infused, ease of placement, risks, and the possible need for rapid large volume resuscitation. there are numerous types of iv catheters encountered in the inpatient setting: peripheral intravenous catheters (pivs), peripherally inserted central catheters (piccs), non-tunneled central venous catheters (cvcs), tunneled cvcs, peripheral rapid infusion catheters (rics), hemodialysis cvcs, implanted ports, and intraosseous (io) catheters. this review summarizes the salient points regarding rapid volume resuscitation for the most encountered iv catheters in the hospital setting. central venous catheters (cvcs) exist in many forms and the decision of which type to place is multifactorial. not all cvcs allow for the high flow rates required for rapid volume resuscitation. for example, a triple lumen catheter is relatively long in length and provides significantly lower flow rates than most pivs (figure 1, table 1). in fact, the 18g port of a triple lumen catheter infuses at a max rate of 26 milliliters/minute (ml/ min) which is less than a 20-gauge piv with a max flow rate of 65 ml/min. therefore, if selecting a cvc, an arrow® multilumen access catheter, arrow® 8.5 introducer, or arrow® double lumen central line would be more appropriate for rapid volume administration since each port can allow for flow over 100ml/ min. the arrow® multi-lumen access catheter and arrow® 8.5 introducer are capable of infusion rates over 500 ml/min and can be used with rapid infuser devices. a large bore cvc is advantageous in the setting of hemorrhage, and clinicians should weigh potential risks. these risks include time needed for placement, vascular injury, and central line associated blood stream infections. the risks should be balanced against the need for rapid infusion and administration of drugs such as vasopressors that can be caustic when infused peripherally. peripherally inserted central catheters (piccs) provide more durable and dependable iv access for patients with limited texas christian university “the science behind the art” volume 11 no.1, 2023 anesthesia ejournal online issn 2333-2611 page 2 peripheral access and those needing long-term infusions. picc lines are both small in diameter and long in length (three times longer than the next longest catheter); therefore, flow rate is slow at ~10 ml/min (figure 1). picc lines have very limited utility in patients needing high-volume resuscitation. rapid infusion catheters (rics) are large bore, short, peripherally inserted catheters that allow for high flow rates. most placed in the operating room environment, rics are typically inserted in the antecubital vein, using the seldinger technique. the large diameter (7 fr and 8.5 fr) and short length allow for rapid volume resuscitation up to 572 ml/min (figure 1, table 1). even though rics are superior to pivs for large volume resuscitation, it is important to note that rics require extra vigilance because high-volume peripheral infiltration and extravasation can occur rapidly and compromise vascular flow in the affected limb leading to compartment syndrome.5,6 peripheral intravenous catheters (pivs) are the most common iv access, primarily because the superficial nature of peripheral veins often allows for simpler and less traumatic access. there are several piv catheter lengths, but flow rate primarily depends on the gauge. furthermore, the relatively short catheter length of pivs favors fast flow rates. the rate of a free-flowing crystalloid infusion ranges from 65 ml/min in a 20-gauge piv to 325 ml/ min in a 14-gauge piv (figure 1). conclusion the purpose of this review and the included infographic and table is to objectively compare the flow rates of the iv catheters commonly used in the hospital setting. this information can help clinicians make an informed decision when choosing an iv catheter. figure 1 illustrates that central venous access is not always superior to peripheral access when it comes to maximum flow rates. we argue that in the setting of acute hemorrhagic shock, one 16g peripheral iv is more effective than a triple lumen cvc. if very rapid fluid resuscitation is required, only the arrow® multi-lumen access catheter, arrow® 8.5 fr introducer, 7.0 fr or 8.5 fr ric, and 14g piv can provide resuscitation at rates over 300ml/min and can be considered true large bore access. 16g pivs and double lumen central lines can provide rates over 200ml/min and thus serve as moderate sized iv access. importantly, the maximum flow rates for triple lumen central lines, piccs, and 20g pivs are well under 100ml/ min and cannot be considered adequate access if rapid volume resuscitation is required. therefore, when choosing between the many different types of iv access that are available, it is critical to understand the poiseuille’s law principles and the integral role of catheter length and radius. references 1. carlisle km, halliwell m, read ae, wells pnt. estimation of total hepatic blood flow by duplex ultrasound. gut. 1992;33:92-97. 2. hall jm, roberts fl. an investigation into the reduction in flow rate of intravenous fluid by antireflux valves. anaesthesia. 2005;60(8):797-800. 3. mcpherson d, adekanye o, wilkes ar, hall je. fluid flow through intravenous cannulae in a clinical model. anesth analg. 2009;108(4):1198-1202. 4. khoyratty si, gajendragadkar pr, polisetty k, ward s, skinner t, gajendragadkar pr. flow rates through intravenous access devices: an in vitro study. j clin anesth. 2016;31:101-105. 5. chou wh, rinderknecht tn, mohabir pk, phillips aw. skin necrosis distal to a rapid infusion catheter: understanding possible complications of large-bore vascular access devices. cureus. 2019;11(1):e3854. 6. dychter ss, gold da, carson d, haller m. intravenous therapy: a review of complications and economic considerations of peripheral access. j infus nurs. 2012;35(2):84-91. 7. arrow. insert. teleflex. 8. pro-picc. insert: medcomp. harleysville, pa. 9. wrenn ea, wohlers r, montgomery m, et al. comparison of flow dynamics of peripherally and centrally inserted intravenous catheters using a rapid infusion system. aana. 2017;85:256-260. texas christian university “the science behind the art” volume 11 no.1, 2023 anesthesia ejournal online issn 2333-2611 page 3 table 1. flow rate comparison for iv devices from manufacturers intravenousaccessdevice flow (ml/min) flow (l/hr) time to infuse1l (minutes) centralvenouscatheters(cvc) arrow® multi-lumenaccesscatheter(mac) 9frdistallumen 12frproximallumen combined 507 30.42 199 11.94 1.97 5.03 706 42.36 1.42 arrow® 8.5fintroducer(cordis) 500 30 2 doublelumencvc lumen1(14 g) lumen2(14 g) combined 127 7.62 100 6 7.87 10 227 13.62 4.41 triplelumencvc lumen1(16 g) lumen2(18 g) lumen3(18 g) 53 3.18 26 1.56 27 1.62 18.87 38.46 37.04 combined 106 6.36 9.43 peripherallyinsertedcentralcatheter(picc) 9.6 0.58 100 peripheralrapidinfusioncatheters(ric) 8.5 fr ric 572 34.32 1.75 7 fr ric 500 30 2 peripheralintravenouscatheters(piv) 14 g piv 325 19.5 3.08 16 g piv 215 12.9 4.65 18 g piv 110 6.6 9.09 20 g piv 65 3.9 15.38 flow rates for iv devices obtained from manufacturers in ml/min, l/hr, and time to infuse one liter of saline in minutes. cvc = central venous catheters, ric = rapid infusion catheters, picc = peripherally inserted central catheter, piv = peripheral intravenous catheter. rates are based on 100 cm height gravity flow rates. some resources may quote slight variations in flow rate, and this may be dependent on the testing conditions or slight variations in lengths for different brands of pivs. texas christian university “the science behind the art” volume 11 no.1, 2023 anesthesia ejournal online issn 2333-2611 page 4 texas christian university “the science behind the art” volume 11 no.1, 2023 anesthesia ejournal online issn 2333-2611 page 5 peripheral ivs (piv)peripheral rapid infusion catheters (ric) central venous catheters (cvc) q = �ow rate (ml/min) r = radius of tubing l = length of tubing p = pressure gradient n = viscosity of �uid fr = french (3x diameter) g = gauge (outer diameter) ��= πpr4 8�� 8.5 fr 10 cm 500 ml/m in intro duce r (cord is) 6.4 cm 8.5 fr 572 ml/m in ml/m in500 7 fr 5 cm 3.2 cm 16 g 215 3.2 cm 18 g 110 2 cm 20 g 65 3 cm 14 g 325 ml/m in 16 cm double lumen 127 100 14 g 14 g { 227 ml/m in 20 cm trip le lumen 16 g 18 g 18 g 53 26 27{ 106 ml.m in 60 cm picc 9.6 ml/m in 12 g mac 9 fr 11.5 cm ml/m in507 199{ 706 ml/m in q r � poiseuille’s law assumptions: viscosity and pressure gradient constant at 1 visual comparison of intravenous catheter types and flow rates 18 g 5 figure 1. a visual comparison of intravenous catheter type and flow rates rates obtained from manufacturers, found on packaging [arrow® multi-lumen access catheter (mac)7, arrow® 8.5 introducer, arrow® double lumen central line, arrow® triple lumen central line, arrow® peripherally inserted central access (picc)8, arrow® 7.0 french and 8.5 french rapid infusion catheter (ric), jelco® peripheral intravenous catheters (piv)]. 9 sizes (radius, length) are all proportional and scaled. arrow width is proportional to flow. rates are based on 100cm height gravity flow rates. some resources may quote slight variations in flow rate, and this may be dependent on the testing conditions or slight variations in lengths for different brands of pivs. educated hand publishing llc “t he science behind the art” volume 6no. 1 2018 anesthesia ejournal online issn 2333-2611 page 1 regional anesthesia for bilateral carpal tunnel release debra s. varela, dnp, crna1 johanna newman, dnap, crna2 jorge a. valdes, dnp, crna3 affiliation: 1. literature review was conducted as partial fulfillment for the degree of doctor of nursing practice in anesthesiology through barry university in miami florida and practicing crna at a critical access hospital in rural north central arkansas 2. crna clinician at anesco north broward in fort lauderdale, fl 3. clinical assistant professor of anesthesiology at florida international university in the college of nursing health sciences funding/conflict of interest disclosure: none keywords: carpal tunnel syndrome, median nerve block, local anesthesia, lidocaine, epinephrine introduction carpal tunnel syndrome (cts) interferes with a patient’s quality of life and has significant financial implications for patients, their employers, and the us health care system.1,2 cts involves compression of the median nerve and is the most common nerve entrapment neuropathy with a prevalence of 3% to 5% in the general population.1 because the average age at the time of diagnosis is 45 to 60 years, cts affects people in the workforce.1 cts is responsible for an average of 28 days away from work according to 2015 data from the bureau of labor statistics.1,2 a reported 56% to 87% of those presenting with median nerve compression symptoms are diagnosed with bilateral involvement, especially patients with diabetes, hypothyroidism, obesity, and inflammatory arthritis.1,3,4 carpal tunnel release (ctr) surgery incurs an estimated health care cost of $2 billion annually in the united states,5 with more than 500,000 persons undergoing ctr surgery every year.6 patients diagnosed with bilateral carpal tunnel syndrome (bcts) are faced with the decision to undergo surgical intervention in a staged unilateral approach or a simultaneous bilateral approach. studies have shown that bilateral carpal tunnel release (bctr) is overwhelmingly more cost-effective and time-efficient than a staged unilateral approach.1,5,6 bilateral hand procedures limit certain regional anesthesia techniques typically employed for unilateral upper extremity procedures, however, requiring reconsideration of more effective anesthesia options.7-9 abstract carpal tunnel syndrome is the most common nerve entrapment neuropathy, and over 60% of diagnosed patients present with bilateral median nerve involvement. bilateral upper extremity surgery presents unique anesthesia challenges, yet surgeons are increasingly interested in performing simultaneous bilateral carpal tunnel release (bctr) procedures. the regional anesthesia techniques traditionally used for unilateral hand procedures are impractical for bilateral procedures, and general anesthesia is expensive and incurs added risk. a cost-effective and efficient anesthesia plan for bctr is therefore needed. we conducted a literature search to support the administration of an efficient and safe anesthesia technique for bctr utilizing local infiltration and median nerve block. electronic searches were conducted to identify current pertinent information published in anesthesia, hand surgery, and plastic surgery journals within the past 5 years. the information gathered was assimilated to make an evidence-based recommendation for a bctr anesthesia technique. bctr is a more cost-effective and time-efficient treatment for bilateral carpal tunnel syndrome than a staged unilateral approach. local anesthesia with median nerve block with or without sedation is a cost-efficient and safe anesthesia strategy for bctr.. aej volume 6 no.1 2018 www.anesthesiaejournal.comanesthesia ejournal volume 6 no.1 2018 page 2 methods electronic searches were conducted through medline (national library of medicine), cinahl (ebsco), and pubmed (national library of medicine) for current pertinent information published in the anesthesia, hand surgery, and plastic surgery literature. the search was limited to 2012 through 2016, with the exception of large, multicenter landmark studies. search sensitivity was increased by using the boolean operators “or” and “and” to combine search categories. the words and phrases searched included the following: bilateral carpal tunnel syndrome/release, bilateral versus staged unilateral carpal tunnel release, median nerve block, regional anesthesia for bilateral hand procedures, local anesthesia with epinephrine and hand surgery, buffering of local anesthetics, general anesthesia versus regional anesthesia: cost and safety, anxiety and anesthesia, sedation, and monitored anesthesia care. review of the literature bilateral carpal tunnel release versus staged unilateral release surgical treatment of bcts can be addressed in a simultaneous approach or a staged unilateral approach.1,4-6 the costand time-effectiveness of bctr compared with staged unilateral carpal tunnel release (sctr) has been well documented. a study evaluating cost-effectiveness published in november 2016 in the journal of the american academy of orthopedic surgeons showed bctr to have a higher total effectiveness and lower cost than sctr.6 a cost and time comparison study between sctr and bctr was also performed by elfar et al,5 who reported a 22% increase in total amount billed including fees for the physician, facility, and anesthesia in the sctr group compared with the bctr group. the average total operating room time for sctr procedures was 66 minutes compared with 40 minutes for bctr procedures.5 additionally, patients undergoing bctr missed an average of 22 days from work, compared with 46 days for patients undergoing a staged unilateral approach.5 physicians also benefit from the simultaneous bctr option by requiring fewer postoperative visits (3.46 for sctr vs 1.45 for bctr), with higher remuneration per hour.4 the primary reason patients report choosing sctr over bctr is concern for independent postoperative self-care, whereas patients choosing bctr over sctr reported wanting to avoid 2 surgical procedures.1 a prospective cohort study by osei et al1 conducted postoperative surveys of both sctr and bctr patients to compare self-care ability. the results revealed increased difficulty with household chores only during the first 2 postoperative days in the bctr group, but no significant difference in personal hygiene performance between the groups.1 anesthesia considerations for bctr bilateral hand procedures limit the use of certain regional anesthesia techniques typically used for unilateral upper extremity procedures, such as brachial plexus block (bpb) and intravenous regional blocks (ivrbs).7,8 local anesthesia toxicity and tourniquet pain are potential complications with these techniques.7-9 postoperative concerns with these methods include bilateral motor blockade with bpb, and the lack of analgesia provided with ivrb following deflation of the tourniquet.7-9 anesthesia techniques practical for consideration for bctr are general anesthesia, local anesthesia, and median nerve block with or without sedation.7-9 both open and endoscopic surgical techniques for bctr are considered minimally invasive procedures according to the clinical practice guidelines of the american association of orthopedic surgeons.3 a pneumatic tourniquet for hemostasis has traditionally been used for this procedure, necessitating anesthesia management for tourniquet pain.10,11 negating the noxious stimuli of a tourniquet eliminates the need for general anesthesia or heavy sedation, thus avoiding their associated risks and expense.10-12 costly preoperative testing may also be eliminated if general anesthesia is not indicated.10,11 regional techniques and local anesthesia alternatives result in less postoperative pain and a shorter recovery room stay than general anesthesia.13 within the past 10 years, wide acceptance of the use of epinephrine for hemostasis has been published in the hand surgery literature. a large multicenter prospective study conducted between 2002 and 2004 through dalhousie university in canada reviewed 3110 consecutive cases in which epinephrine was electively injected into the hand with no incidence of tissue loss.12 the long-held belief that epinephrine in finger and hand surgery is contraindicated was dispelled.10-12 the acceptance of epinephrine-containing local anesthetics in hand surgery enables local infiltration and median nerve block as an effective, safe anesthetic technique for bctr.10,11 sedation and patient anxiety in 2 separate patient satisfaction studies comparing patients undergoing ctr under local anesthesia only to local anesthesia with sedation, one by rozanski et al14 and the other by davison et al,15 the investigators found no difference in overall satisfaction with their procedure, with 93% of patients reporting satisfaction with whichever technique they received. a preponderance of available literature supporting the use of a local anesthesia only technique termed “wide awake local anesthesia no tourniquet” (walant) has been published by lalonde et al.10-12,15 comparison studies conducted by lalonde’s group evaluating patient satisfaction between nonsedation and sedation techniques showed no significant differences in satisfaction; however, surgical conditions and local anesthesia techniques were not standardized between the groups.15 in the study conducted by rozanski et al14 to specifically evaluate pain perception on injection and during the procedure between sedation and nonsedation groups, significantly higher pain on injection and during the surgery was reported in the local anesthesia only groups. despite these findings, the authors supported the use of local anesthesia only owing to the reduced need for a thorough preoperative workup, intravenous access, intraoperative monitoring, and recovery room time compared with the sedation technique.14,15 studies designed to evaluate patient satisfaction, anxiety, and comfort with equal surgical and local anesthesia techniques between sedated and nonsedated patients were not available in the reviewed literature. patient anxiety related to regional anesthesia has been reported as primarily related to fear of pain, awareness, and not knowing what to expect.16-18 preoperative consultation with patients describing the procedure, medical equipment, terminology, and postoperative expectations has been identified as a means to greatly decrease anxiety in regional anesthesia patients.16-18 the patient’s health status, as well as acceptance of increased pain during the injection www.anesthesiaejournal.comanesthesia ejournal volume 6 no. 1 2018 page 3 and procedure, are factors in proposing this regional anesthesia plan with or without sedation.14,15 comparison of injection technique two local anesthesia injection techniques have been described for carpal tunnel decompression procedures: the altissimi and mancini technique, in which a local anesthetic is infiltrated into the carpal tunnel to anesthetize the median nerve as well as subcutaneously for surgical analgesia, and the gale technique, which involves only superficial infiltration without a median nerve block.19,20 a randomized controlled single-blinded trial reported in the journal of hand surgery by patil et al20 evaluated analgesic levels between the 2 techniques for patients undergoing bctr in a staged unilateral sequence separated by 4 to 8 weeks. the gale technique was used on one hand, and the altissimi and mancini on the other.20 of the 20 patients evaluated, the altissimi and mancini technique was found to produce complete analgesia in all of the patients compared with the gale technique, in which 30% of patients complained of intraoperative pain.20 similarly, a nonrandomized prospective interventional trial reported in the journal of the institute of medicine by sigdel et al19 concluded that the altissimi and mancini technique provides reliable intraoperative analgesia. neither of the studies reported the incidence of median nerve injury with infiltration of the carpal tunnel.19,20 lidocaine is most commonly reported as the local anesthesia agent of choice for minor hand surgery procedures owing to its safety record compared with other local anesthesia agents.10,11 the addition of epinephrine to lidocaine serves to extend the block duration, acts to provide hemostasis, and raises the toxic dose limit, thus allowing for a greater volume to be used.10,11,15 the average duration of 1% lidocaine with 1:100,000 epinephrine is 4 to 5 hours, adequate to provide analgesia for the intraoperative and postoperative period for bctr procedures.10 an upper limit of 7 mg/kg of lidocaine with epinephrine is widely accepted as a safe toxic dose limit allowing for ample volume of 1% lidocaine with 1:100,000 epinephrine to be used.10,11 the use of lidocaine with epinephrine is reported extensively as a safe local anesthesia throughout the dental and plastic surgery literature.10,11 modifications to reduce pain on injection related to the initial needle stick and stinging affiliated with local anesthesia infiltration were identified in the literature reviewed. such modifications included using a small 25to 27-gauge needle for injection, introducing the needle perpendicularly to the skin, advancing the needle slowly behind the field of existing local anesthesia, and buffering the lidocaine with sodium bicarbonate to achieve ph normalization.21-23 an original study by frank and lalonde22 concluded that 1% lidocaine with 1:100,000 epinephrine has an average ph of 4.2 to 4.7 and is reliably normalized to a target tissue ph of 7.38 to 7.62 with the addition of 1 ml 8.4% sodium bicarbonate to every 10 ml of local anesthetic (10:1 ratio). hands-on: performing the injection for successful performance of the altissimi and mancini injection technique, the literature stresses the importance of reviewing the median nerve anatomy to avoid intraneural injury with a carpal tunnel injection. the median nerve becomes superficial at the distal forearm proximal to the wrist.24 it traverses the carpal tunnel, medial to the flexor carpi radialis tendon, and deep and radial to the palmaris longus (pl) tendon (figure 1).24 the median nerve innervates the palmar surface of the thumb, index, middle, and the lateral half of the ring finger, including the nail beds on the dorsal surface.24 an atraumatic injection of the carpal tunnel can be accomplished with familiarization of median nerve anatomy (figure 1),24 and utilization of a 45-degree radial and distal needle angle just ulnar to the pl tendon (figure 2).19,20,24 figure 1. cross sectional anatomy of carpal tunnel. illustration credit: debar varela, 2017. figure 2. modified altissimi and mancini19,20 carpal tunnel injection as described by farhangkhoee et al25 in line with the radial border of the ring finger at a 45-degree radial and distal angle. superficial landmarks for infiltration: radial border of the ring finger from the proximal palmar crease to the distal wrist crease. the diagonal line depicts kaplan’s cardinal line, the distal most extent of an open or endoscopic carpal tunnel release, sparing the superficial palmar arch from transection.26 image credit: debra varela, 2016. a modification of the altissimi and mancini technique, termed the “hole-in-one” technique, has been described and utilized extensively by lalonde.27 reliable replication of the technique was highlighted in a study conducted at dalhousie university in canada by farhangkhoee et al25 in which 25 consecutive medical students (36%) and residents (64%) observed the injection one time and then independently demonstrated the technique on the next patient. pain score data were collected immediately after the demonstration by asking the patient how many times pain was felt during the injection utilizing the “hole-in-one” technique.25 of the 25 patients injected, 66% felt pain on only the first stick, termed a “hole-in-one,” while 24% reported feeling 2 needle sticks, which was termed an “eagle.”25 technique standardization of the hole-in-one technique included the following. a total of 20 ml of 1% lidocaine with 1:100,000 epinephrine and 2 ml of 8.4% bicarbonate for each carpal tunnel injection was prepared.27 a 27-gauge needle was first introduced in line with the ring finger at the distal wrist crease, at a 45-degree radial direction, and 10 ml was injected into the carpal tunnel for the median nerve block.25,27 the remaining 10 ml was infiltrated into the palm in line with the radial side of the ring finger (figure 2),26 with care given to advance the needle within the field of existing local anesthesia, avoiding needle contact with unanesthetized tissue.25,27 kaplan’s cardinal line as depicted by the transverse palmar line (figure 2) provides a reference point to the superficial palmar arterial arch. the kaplan’s cardinal line landmark is referenced as the distal most extent of an open or endoscopic ctr by hand surgeons and ensures that the superficial palmar arch is free of transection.26 the intersection of the palmar lines serves as a reference point for local infiltration for the incision site.26 pain level was described by the volunteer patient population as less than the pain experienced with local dental anesthesia by 84%, and 64% rated it as less pain than with the insertion of a 20-gauge intravenous needle used for providing sedation.27 while the researchers conceded that the study may have been skewed by patients feeling obligated to support students, the technique was found to be easily replicated.27 summary the literature selected for review included descriptive nonexperimental, observational review, and case-control studies. the data supporting bctr versus sctr revealed cost and time savings for patients and surgeons.1,4-6 documentation of the desire to perform bctr in a simultaneous fashion and the limitations of certain anesthetic techniques with bilateral upper extremity surgeries validate the need for an efficient, evidence-based anesthesia plan.7-9 the acceptance of epinephrine-containing local anesthetics in the hand surgery literature has made performing hand procedures such as ctr without the use of a tourniquet possible, thereby negating the use of a pneumatic tourniquet and associated tourniquet pain.10-12,14,15 much of the recent literature reviewed has cited or been authored by lalonde and his associated researchers on the use of walant for hand surgeries including ctr. the costand time-effectiveness of walant has been documented in studies that compared cost, safety, and patient satisfaction.11,14,15,27 lalonde et al have proposed that most ctr procedures can be performed with walant with resultant high patient satisfaction, improved safety, and decreased cost.10,11,15,21,25,27 ctr procedures in canada are performed 90% of the time with local anesthesia only and no tourniquet.27 in contrast, most ctr procedures in the united states are performed by use of a tourniquet either with sedation or with general anesthesia.27 a gap in the literature was found to exist in the comparison of patient satisfaction with local anesthesia only with the same local anesthesia technique with sedation with regard to decreased anxiety and increased satisfaction with simultaneous bctr procedures. additionally, studies designed to quantify the level and type of sedation as related to patient satisfaction with ctr surgery were lacking. while expense and efficiency are important driving factors, patient comfort and psychological well-being are equally important considerations. factors increasing anxiety in patients undergoing local anesthesia were addressed in a study by caddick et al,16 who found that aside from obvious factors such as fear of pain, the use of “surgical jargon” and the operating room environment itself contribute to anxiety. caddick et al16 suggested that an increase in patient anxiety during the perioperative period has an overall negative impact on patient recovery. attempts to reduce the stressful aspects of the operative process could therefore result in a positive psychological and physical response to surgery.16 as local and regional anesthetic techniques are used more frequently with outpatient surgical procedures, consideration of factors beyond analgesia having an impact on patient comfort is required.17,18 each patient is an individual, and a simple procedure in the eyes of one patient may result in emotional distress in another.17 formulation of the anesthesia plan and preoperative consultation should be individualized according to the patient’s physical health and psychological needs.17,18 future research into the effect of local anesthesia and median nerve block with sedation on anxiety and satisfaction with bctr could add valuable information for anesthesia providers caring for these patients. www.anesthesiaejournal.comanesthesia ejournal volume 6 no. 1 2018 page 4 references 1. osei da, calfee rp, stepan jg, boyer mi, goldfarb ca, gelberman rh. simultaneous bilateral or unilateral carpal tunnel release? a prospective cohort study of early outcomes and limitations. j bone joint surg am. 2014;96(11):889-896. https://doi. org/10.2106/jbjs.m.00822. 2. bureau of labor statistics. nonfatal occupational injuries and illnesses requiring days away from work, 2015. us department of labor website. http://www.bls.gov/news.release/pdf/osh2.nr0.htm. published november 10, 2016. accessed november 16, 2016. 3. keith mw, masear v, chung kc, et al. american academy of orthopaedic surgeons clinical practice guideline on the treatment of carpal tunnel syndrome. j bone joint surg am. 2010;92(1):218-219. https://doi.org/10.2106/jbjs.i.00642. 4. phillips p, kennedy j, lee t. cost effective analysis of simultaneous versus staged bilateral carpal tunnel release. presented at: american association of hand surgeons annual meeting; january 21-25, 2015; paradise island, bahamas. http://meeting. handsurgery.org/abstracts/2015/104.cgi. 5. elfar jc, foad mb, foad sl, stern pj. a cost analysis of staged and simultaneous bilateral carpal tunnel release. hand (ny). 2012;7(3):327-332. https://doi.org/10.1007/s11552-012-9436-y. 6. park kw, boyer mi, gelberman rh, calfee rp, stepan jg, osei da. simultaneous bilateral versus staged bilateral carpal tunnel release: a cost-effectiveness analysis. j am acad orthop surg. 2016;24(11):796-804. https://doi.org/10.5435/ jaaos-d-15-00620. 7. sørensen am, dalsgaard j, hansen tb. local anaesthesia versus intravenous regional anaesthesia in endoscopic carpal tunnel release: a randomized controlled trial. j hand surg eur vol. 2013;38(5):481-484. https://doi.org/10.1177/1753193412453664. 8. holborow j, hocking g. regional anaesthesia for bilateral upper limb surgery: a review of challenges and solutions. anaesth intensive care. 2010;38(2):250-258. 9. chalidis be, dimitriou cg. one portal simultaneous bilateral endoscopic carpal tunnel release under local anaesthesia. do the results justify the effort? int orthop. 2013;37(8):1501-1505. https://doi.org/10.1007/s00264-013-1951-0. 10. al youha s, lalonde dh. al youha s, lalonde dh. update/review: changing of use of local anesthesia in the hand. plast reconstr surg glob open. 2014;2(5):e150. https://doi.org/10.1097/gox.0000000000000095. 11. lalonde d, martin a. epinephrine in local anesthesia in finger and hand surgery: the case for wide-awake anesthesia. j am acad orthop surg. 2013;21(8):443-447. https://doi.org/10.5435/jaaos-21-08-443. 12. lalonde d, bell m, benoit p, sparkes g, denkler k, chang p. a multicenter prospective study of 3,110 consecutive cases of elective epinephrine use in the fingers and hand: the dalhousie project clinical phase. j hand surg am. 2005;30(5):10611067. https://doi.org/10.1016/j.jhsa.2005.05.006. 13. corey jm, bulka cm, ehrenfeld jm. is regional anesthesia associated with reduced pacu length of stay? a retrospective analysis from a tertiary medical center. clin orthop relat res. 2014;472(5):1427-1433. https://doi.org/10.1007/s11999-0133336-5. 14. rozanski m, neuhaus v, reddy r, jupiter jb, rathmell jp, ring dc. an open-label comparison of local anesthesia with or without sedation for minor hand surgery. hand (ny). 2014;9(4):399-405. https://doi.org/10.1007/s11552-014-9670-6. 15. davison pg, cobb t, lalonde dh. the patient’s perspective on carpal tunnel surgery related to the type of anesthesia: a prospective cohort study. hand (ny). 2013;8(1):47-53. https://doi.org/10.1007/s11552-012-9474-5. 16. caddick j, jawad s, southern s, majumder s. the power of words: sources of anxiety in patients undergoing local anaesthetic plastic surgery. ann r coll surg engl. 2012;94(2):94-98. https://doi.org/10.1308/003588412x13171221501267. 17. ruspantine p. the preoperative anesthesia evaluation--revisited. aana j. 2015;83(2):83-84. 18. mitchell m. influence of gender and anaesthesia type on day surgery anxiety. j adv nurs. 2012;68(5):1014-1025. https://doi. org/10.1111/j.1365-2648.2011.05801.x. 19. sigdel a, uprety s, govind kc. modified altissimi and mancini technique for carpal tunnel decompression. journal of institute of medicine. 2012;34(1):9-12. http://dx.doi.org/10.3126/joim.v34i1.9116 20. patil s, ramakrishnan m, stothard j. local anaesthesia for carpal tunnel decompression: a comparison of two techniques. j hand surg br. 2006;31(6):683-686. https://doi.org/10.1016/j.jhsb.2006.08.008. 21. strazar ar, leynes pg, lalonde dh. minimizing the pain of local anesthesia injection. plast reconstr surg. 2013;132(3):675684. https://doi.org/10.1097/prs.0b013e31829ad1e2. 22. frank sg, lalonde dh. how acidic is the lidocaine we are injecting, and how much bicarbonate should we add? can j plast surg. 2012;20(2):71-73. https://doi.org/10.1177/229255031202000207. www.anesthesiaejournal.comanesthesia ejournal volume 6 no. 1 2018 page 5 https://doi.org/10.2106/jbjs.m.00822 https://doi.org/10.2106/jbjs.m.00822 http://www.bls.gov/news.release/pdf/osh2.nr0.htm https://doi.org/10.2106/jbjs.i.00642 http://meeting.handsurgery.org/abstracts/2015/104.cgi http://meeting.handsurgery.org/abstracts/2015/104.cgi https://doi.org/10.1007/s11552-012-9436-y https://doi.org/10.5435/jaaos-d-15-00620 https://doi.org/10.5435/jaaos-d-15-00620 https://doi.org/10.1177/1753193412453664 https://doi.org/10.1007/s00264-013-1951-0 https://doi.org/10.1097/gox.0000000000000095 https://doi.org/10.5435/jaaos-21-08-443 https://doi.org/10.1016/j.jhsa.2005.05.006 https://doi.org/10.1007/s11999-013-3336-5 https://doi.org/10.1007/s11999-013-3336-5 https://doi.org/10.1007/s11552-014-9670-6 https://doi.org/10.1007/s11552-012-9474-5 https://doi.org/10.1308/003588412x13171221501267 https://doi.org/10.1111/j.1365-2648.2011.05801.x https://doi.org/10.1111/j.1365-2648.2011.05801.x http://dx.doi.org/10.3126/joim.v34i1.9116 https://doi.org/10.1016/j.jhsb.2006.08.008 https://doi.org/10.1097/prs.0b013e31829ad1e2 https://doi.org/10.1177/229255031202000207 23. salati sa. minimizing the pain in local anesthesia injection-a review. j pak assoc dermatol. 2016;26(2):138-43. 24. bodle, ethan e. "median nerve block." overview, indications, contraindications 4 sept. 2015, emedicine.medscape.com/ article/1369028-overview. accessed november 16, 2016. 25. farhangkhoee h, lalonde j, lalonde dh. teaching medical students and residents how to inject local anesthesia almost painlessly. can j plast surg. 2012;20(3):169-172. https://doi.org/10.1177/229255031202000315. 26. panchal ap, trzeciak ma. the clinical application of kaplan’s cardinal line as a surface marker for the superficial palmar arch. hand (ny). 2010;5(2):155-159. https://doi.org/10.1007/s11552-009-9229-0. 27. lalonde dh. “hole-in-one” local anesthesia for wide-awake carpal tunnel surgery . plast reconstr surg. 2010;126(5):1642-1644. https://doi.org/10.1097/prs.0b013e3181f1c0ef. www.anesthesiaejournal.comanesthesia ejournal volume 6 no. 1 2018 page 6 https://doi.org/10.1177/229255031202000315 https://doi.org/10.1007/s11552-009-9229-0 https://doi.org/10.1097/prs.0b013e3181f1c0ef texas christian university “the science behind the art” volume 10 no.3 2022 anesthesia ejournal online issn 2333-2611 page 9 comparison of quadratus lumborum block and transversus abdominis plane block for postoperative pain management kristina alexis whitely, bsn, rn, ccrn affiliation: texas christian university grant/financial support: none keywords: regional anesthesia, abdominal, quadratus lumborum block, transversus abdominis plane block, interfascial plane block abstract enhanced recovery after surgery (eras) protocols for open abdominal cases suggest preoperative epidural, wound catheter, or transversus abdominis plane (tap) block placement can be effective for postoperative pain management.1 this case-based poster presents a middle-aged woman who undergoes a pancreatoduodenectomy (pd) and receives a postoperative fascial plane block, a quadratus lumborum (ql) block, rather than the currently recommended tap block, wound infiltration, or neuraxial anesthesia. based on quality evidence regarding the benefits of the ql block, expanding eras protocols to regional anesthesia beyond wound infiltration and tap blocks has the potential to produce increased pain management postoperatively, aiding in enhanced recovery and improved outcomes. aej volume 10no. 3 2022 about the author: kristina “alexis” whiteley is a doctoral student at texas christian university school of nurse anesthesia, class of 2022. she has an adn from victoria, texas, 2016, as well as a bsn from university of texas at arlington, 2018. alexis has worked in the micu/sicu and cvicu in arlington, texas. the author currently lives in the fort worth area with primary residency at john peter smith ( jps) level 1 trauma center, fort worth, texas. texas christian university “the science behind the art” volume 10 no.3 2022 anesthesia ejournal online issn 2333-2611 page 10 p o w e rp o in t t e m p la te © 2 0 0 9 t e x a s c h r is t ia n u n iv e rs it y , c e n te r fo r in s t ru c t io n a l s e rv ic e s . f o r e d u c a t io n a l u s e o n ly . c o n te n t is th e p ro p e r ty o f th e p re s e n te r a n d th e ir r e s o u rc e s . figure 1. cross section of tlf and muscles viewed during us for ql block6 figure 2. demonstration of posterior, ql2 block. la injected posterior to ql and adjacent to/or within the lift6 figure 3. demonstration of anterior, ql3 block. la injected between ql and psoas major muscles6 figure 4. cross section of anterolateral muscles, myofascial planes, and surrounding tissues for tap block6 introduction • enhanced recovery after surgery (eras) guidelines for pancreatoduodenectomy surgery suggests preop epidural, wound infiltration (wi), or transversus abdominis plane (tap) block for postop pain management1 • although tap block reduces overall opioid consumption and enhances rapid recovery when compared with neuraxial anesthesia,2 tap blocks only provide somatic analgesia • quadratus lumborum (ql) blocks are an alternative fascial plane block, aside from tap block, that provides substantially increased analgesia spread • ql block spread shown to aid in visceral and somatic analgesia due to injected local anesthetic (la) spreading to thoracolumbar fascia (tlf), targeting sympathetic fibers and paravertebral space3 transversus abdominis plane block • tap approaches: subcostal, lateral, anterior & posterior • blocks ventral rami of spinal nerves t7-t10 located in plane between internal oblique muscle (iom) and transversus abdominis muscle (tam)6 • blocks anterolateral skin, muscles, and parietal peritoneal sensory nerve fibers of abdominal wall4 • no inhibitory effect on visceral pain, only somatic • complications researched include abdominal organ injury, nerve injury, vascular injury4 • compared to the gold standard epidural, tap blocks result in significantly less opioid consumption, postop pain, and incidences of hypotension, with no difference in opioid consumption at 72 hrs2 • when compared to ql blocks, tap blocks are shown to have increase patient pain scores, opioid consumption, and number of patients requiring analgesia postoperatively3 quadratus lumborum block vs. transversus abdominis plane block kristina “alexis” whiteley, bsn, rn, texas christian university case summary pre-anesthetic evaluation • 58-year-old disabled female, nkda, asa 2, bmi 31.2 • history of pancreatic head mass & obstructive jaundice status post biliary stent • medical history: anxiety & gerd • surgical history: egd & ercp • home medications: pantoprazole 40 mg po q morning • preoperative medications: acetaminophen 650 mg po, celecoxib 200 mg po, gabapentin 300 mg po, transdermal scopolamine & midazolam 2 mg iv intraoperative course • general anesthesia induction: rsi with iv ketamine 50 mg, lidocaine 100 mg, & propofol 150 mg; muscle relaxation via succinylcholine 120 mg • antibiotics & adjuncts: cefepime 2 g, dexamethasone 8 mg, magnesium sulfate 2 g bolus, lidocaine drip 2000 mg/500 ml at 2 mg/min • maintenance: isoflurane, rocuronium titrated to twitches, 1 prbc & 2 plt received • opioids & pain adjuncts: fentanyl 200 mcg, hydromorphone 2 mg, ketamine 10 mg/hr for a total of 50 mg postoperative course • postoperative ql block: ultrasound (us) guided, ql2 technique with 25 ml 0.25% bupivacaine bilaterally • awake extubation, patient transferred to pacu comfortably post-extubation, with 8 l/min oxygen via simple facemask • 24-hr follow-up: 4/10 pain at rest, 5/10 pain during movement & patient verbalizes pain ”relatively well controlled” references 1.melloul e, lassen k, roulin d, et al. guidelines for perioperative care for pancreatoduodenectomy: enhanced recovery after surgery (eras) recommendations. 2019. world j of surg. 2020;44:2056-2084. 2.desai n, el-boghdadly k, albrecht e. epidural vs transversus abdominis plane block for abdominal surgery: a systematic review, meta-analysis and trial sequential analysis. anaesthesia. 2021;76(1):101-117. 3. liu x, song t, chen x, et al. quadratus lumborum block versus transversus abdominis plane block for postoperative analgesia in patients undergoing abdominal surgeries: a systematic review and meta-analysis of randomized controlled trials. bmc anesthesiology. 2020;20:5353. 4.wang y, wang x, zhang k. effects of transversus abdominis plane block versus quadratus lumborum block on postoperative analgesia: a meta-analysis of randomized controlled trials. bmc anesthesiology. 2020;20:103. https://doi.org/10.1186/s12871-020-01000-2 5.akerman m, pejcic n, velickovic i. a review of the quadratus lumborum block and eras. frontiers in medicine. 2018;5:44. doi: 10.3389/fmed.2018.00044 6.block buddy pro. version 1.0.7. newbury, oh: block buddy, llc; 2019. quadratus lumborum block • ql approaches: qlb 1, qlb 2, qlb 3 • blocks dorsal rami—somatic analgesia to skin & muscles of posterior abdominal wall6 • blocks ventral rami—somatic analgesia to skin & muscles of anterolateral abdominal wall6 • blocks sympathetic trunk within tlf—visceral analgesia of the abdomen6 • la spread within tlf potentially reaches paravertebral space, generating indirect paravertebral block3 • needle passage is further from abdominal organs, great vessels, and peritoneal cavity4 • fascial plane blocks require volume for adequate spread; current practice suggests a max la dose of 2.5 mg/kg5 discussion • a systemic review (sr) & meta-analysis of 22 rcts comparing postop analgesia of tap & ql blocks showed a statistical decrease in opioid consumption, visual analogue scale (vas) scores at 24 hrs postop, number of patients requiring postop analgesia within ql group • in lieu of current eras guidelines, ql blocks tout clinical superiority in postoperative analgesia when compared to tap blocks case critique • after 6-hour, open abdominal case, outcomes demonstrated stark similarities to current literature over ql efficacy • eras guidelines for pd procedure were followed, with alternative interfascial plane block—ql block—used instead of wi, tap block, or epidural • patient was ambulating the day after surgery, with well managed pain of 4/10 at rest and 5/10 upon activity conclusions & recommendations • regional anesthesia, specifically truncal blocks, are a major component of multimodal pain management for enhanced postoperative recovery • ql blocks have proven clinically superior to tap blocks for multiple major surgeries involving anterior & lateral abdominal wall3,4 • based on quality evidence, eras protocols for pd and other open abdominal cases should be expanded to ql blocks for postoperative analgesic management recommendations for research • larger rcts with asa i-iv, as well as bmis > 30 kg/m2 should be considered for increased generalizability of data • evaluation of la diffusion via the tlf & adjacent structures to validate mechanism of action figure 5. demonstration of tap block via anterolateral approach. la is injected between iom and tam6 volume 7no. 4 2019 educated hand publishing llc “the science behind the art” volume 7 no. 4 2019 anesthesia ejournal online issn 2333-2611 page 13 opioid free anesthesia: a gender reassignment case report chelsea barnett, rrna affiliation: texas christian university keywords: opioid free anesthesia, opioid crisis, gender reassignment, gender dysphoria abstract opioid free anesthesia (ofa) is gaining popularity as an anesthetic technique to enhance surgical recovery and reduce opioid consumption within the postoperative period. for many decades and continuing today, opioids are administered throughout the perioperative period. opioid use has dramatically risen and opioid overdose has earned the leading cause of unintentional death in the united states.1 opioids contain many unfavorable side effects such as potential for abuse or misuse, nausea, vomiting, constipation, ileus, pruritus, altered mental status, urinary retention, respiratory complications, and increased length of hospital stay.1,2 anesthesia professionals play a role in patient’s exposure to opioids, as many patients’ first exposure to opioids may be during the perioperative period.1 an ofa technique was selected for this gender reassignment case to ensure a shorter surgical recovery while avoiding the undesirable side effects of opioids. ofa is a multimodal anesthesia technique including hypnotics, nmda antagonists, local anesthetics, anti-inflammatory drugs, and alpha-2 agonists.4 aej powerpoint template ©2009 texas christian university, center for instructional services. for educational use only. content is the property of the presenter and their resources. purpose • an ofa technique was selected for this gender reassignment case report to ensure a shorter surgical recovery while avoiding the undesirable side effects of opioids. abstract • opioid free anesthesia (ofa) is gaining popularity as an anesthetic technique to enhance surgical recovery and reduce opioid consumption within the postoperative period. • ofa is a multimodal anesthesia technique including hypnotics, nmda antagonists, local anesthetics, anti-inflammatory drugs, and alpha-2 agonists.4 • opioid use has dramatically risen and opioid overdose has earned the leading cause of unintentional death in the united states.1 • opioids contain many unfavorable side effects such as potential for abuse or misuse, nausea, vomiting, constipation, ileus, pruritus, altered mental status, urinary retention, respiratory complications, and increased length of hospital stay.1,2 • anesthesia professionals play a role in patient’s exposure to opioids, as many patients’ first exposure to opioids may be during the perioperative period.1 • while gender dysphoria (gd) by itself may not trigger substance abuse, the stress-related diagnosis can be. discussion • koepkel et al found the incidence of chronic opioid use after surgery was roughly 6% and this did not differ between major and minor surgical procedures in a retrospective study of over 36,000 opioid-naïve patients undergoing elective surgery in the usa between 2013 and 2014.2 • ofa technique: boysen, pappas, and evans6 suggest continuous infusions of lidocaine and dexmedetomidine with a supplement of low dose volatile anesthetic agent and intermittent dosing of acetaminophen, ketamine, ibuprofen, and ketorolac.6 • in this case report, 400 mg celecoxib, 400 mg gabapentin, and 975 mg acetaminophen were administered preoperatively. • celecoxib selectively inhibits cox-2 to prevent and decrease inflammation.7 the recommended dosage of celecoxib is 200 to 400 mg one hour prior to surgery.7 gabapentin binds to voltage-gated calcium channels and inhibits the release of excitatory neurotransmitters.5 • gabapentin is used for chronic neuropathic pain, however, gabapentin has been found to reduce acute pain and reduce opioid consumption.5 graff and grosh stated a normal dose of gabapentin is 300 to 1200 mg three times a day.5 however, there has been an analgesic ceiling effect reported at 600 mg.7 • acetaminophen in dosages of 400 and 800 mg were shown to have an analgesic and opioid-sparing effect in postoperative patients.6 • anesthetic maintenance was maintained with magnesium, lidocaine, and dexmedetomidine infusions. • magnesium acts as a non-competitive antagonist of the nmda glutamate receptor that prevents depolarization and transmission of pain signals.7 • magnesium is typically given by a loading dose of 30-50 mg/kg followed by a maintenance dose of 6-20 mg/kg/hr until the end of surgery.7 • lidocaine blocks the sodium channels, however, the mechanism behind pain control is yet to be entirely understood.5 nevertheless, lidocaine is capable of producing analgesic, anti-inflammatory, and anti-hyperalgesic properties.6 a lidocaine infusion of 0.03 mg/kg/min is recommended following induction and for procedures of less than two hours of duration, a bolus dose of lidocaine can be considered.6 • dexmedetomidine is an alpha-2 agonist that contains analgesic, sedative, and hypnotic properties.6 dexmedetomidine is highly selective and specific for the alpha receptor and reduces potassium efflux and calcium influx, causing hyperpolarization to reduce norepinephrine release.5 direct alpha2 receptor stimulation also impedes nociceptive neuronal firing, making dexmedetomidine a useful option for perioperative pain control.5 dexmedetomidine is recommended to be infused at 0.5 mcg/kg/hr as an intravenous infusion following induction and for procedures of less than two hours duration, a bolus dose can be considered.6 • at the end of the case, ketorolac 30 mg was administered. • ketorolac is a nonsteroidal anti-inflammatory drug (nsaid) that inhibits prostaglandin synthesis through the cox-1 and cox-2 mechanism of action.6 for adult patients, a 15-30 mg intravenous dose of ketorolac has been shown to be safe and effective.6 opioid free anesthesia: a gender reassignment case report chelsea barnett, rrna, texas christian university case summary • a 40-year-old, 63.5 kg, 167.6cm male presented for an orchiectomy, penectomy, and vaginoplasty for gender dysmorphia. • past medical history: attention deficit hyperactivity disorder (adhd) and former smoker for one pack year. surgical history included a laparoscopic cholecystectomy without any anesthesia complications reported. • no known drug allergies. the patient’s medications were delestrogen, ondansetron, and dextroamphetamine. laboratory results were unremarkable. • celecoxib 400 mg, gabapentin 400 mg, acetaminophen 975 mg were administered orally, and a scopolamine 1 mg patch was applied topically to the patient in the pre-operative holding area. • pre-induction vital signs: pulse 73, blood pressure 109/76 mm hg, oxygen saturation (spo2) 99%, respirations 16, and temperature 36.6o c. • oxygen was administered with a facemask at 15 l/min for 5 minutes and until expired oxygen concentrations were greater than 85%. • the patient was induced with lidocaine 60 mg and propofol 200 mg intravenously. a laryngeal mask airway (lma) #4 was applied and placement verified with visible chest rise, bilateral breath sounds, and sustained end-tidal co2 with capnography. the patient was able to spontaneously breathe throughout the procedure. • decadron 8 mg and cefazolin 1 g were administered intravenously prior to the surgical incision. • a total of 2 g magnesium, 20 mcg dexmedetomidine, and 50 mg of lidocaine were infused intravenously throughout the procedure. • anesthesia was initiated with sevoflurane 1.0% end-tidal concentration and titrated between 0.5 to 0.8 minimum alveolar concentration (mac) as tolerated in a mixture of medical air 1 l/min and oxygen 1 l/min. • ketorolac 30 mg was administered intravenously at time of surgical wound closure. • the patient maintained spontaneous respirations between 8-16 breaths per minute with adequate tidal volumes. the lma was removed and the patient maintained a patent airway. oxygen was delivered via facemask at 10 l/min for 5 minutes prior to transferring the patient to the postanesthesia care unit (pacu). • vital signs following the procedure were pulse 67, blood pressure 102/65 mm hg, respirations 14, spo2 98%, and temperature 36.4oc. total pacu time was 30 minutes. • the patient was admitted for overnight observation and evaluation. a same day follow-up evaluation revealed stable vital signs, no postoperative nausea or vomiting, and a pain score of one. • a post-operative day one evaluation revealed the patient received a onetime dose of fentanyl 25 mcg intravenously in the pacu and one tablet by mouth of oxycodone-acetaminophen 5-325 mg over night during observation. • the patient was discharged with no opioid prescriptions. references 1. lavand’hommea p, estebe jp. opioid-free anesthesia: a different regard to anesthesia practice. curr opin anaesthesiol. 2018;31(5):556-561. doi:10.1097/aco.0000000000000632. 2. koepkel ej, manning el, miller te, et al. the rising tide of opioid use and abuse: the role of the anesthesiologist. perioper med (lond). 2018;7(16):1-10. doi:10.1186/s13741-018-0097-4. 3. byne w, karasic dh, coleman e, et al. gender dysphoria in adults: an overview and primer for pyschiatrists. transgend health. 2018:3(1):57-73. pmid:29756044. 4. beloeil h, laviolle b, menard c, et al. pofa trial study protocol: a multicentre, double-blind, randomised, controlled clinical trial comparing opioid-free versus opioid anaesthesia on postoperative opioid-related adverse events after major or intermediate noncardiac surgery. bmj open. 2018;8(6):e020873. doi:10.1136/bmjopen-2017-020873. 5. graff v, grosch t. multimodal analgesia and alternatives to opioids for postoperative analgesia. apsf newsletter. 2018;33(2):46-48. 6. boysen pg, pappas mm, evans b. an evidence-based opioid-free anesthetic technique to manage perioperative and periprocedural pain. ochsner j. 2018;18(2):121-125. pmid:30258291. 7. hornyak, m. (2018). current trends in opioid free anesthesia. available from: https://www.aanesthetists.com/wpcontent/uploads/2018/05/14_current-trends-in-opioid-freeanesthesia.pdf. accessed october 15, 2018. 8. opioid overdose crisis. national institute on drug abuse. available from: https://www.drugabuse.gov/drugs-abuse/opioids/opioidoverdose-crisis. accessed october 15, 2018. summary • every day in the united states, there are more than 115 people who die from opioid overdose.8 • the centers for disease control and prevention estimated the economic burden of prescription opioid misuse in the united states to be $78.5 billion a year.8 • anesthesia professionals play an important role in the opioid epidemic by participating in ongoing education on multimodal pain management such as implementing ofa techniques. • barriers to applying ofa techniques such as the lack of sufficient guidelines, unfamiliarity with the medications used for ofa, resistance to change, cost of ofa, and limited data or the need for more evidence-based practice.7 • benefits of an ofa technique include minimizing respiratory depression, increasing hemodynamic stability intraoperatively, reducing postoperative opioid consumption, reducing length of hospital stay, and reducing the risk of opioid-related side effects.7 • ofa technique was selected for this gender reassignment case report in a patient with risk factors for opioid misuse, abuse, and side effects due to the possibility of the patient experiencing poor social support, psychological minority stress, vulnerability, and societal discrimination.3 • research emerges daily on ofa techniques and it is the anesthesia professionals’ responsibility to remain current on innovative and alternative strategies to provide the safest care to our patients. gender dysphoria • gd is defined as causing distress due to incongruity between one’s experienced or expressed gender and one’s assigned gender and/or primary or secondary sex characteristics.3 • byne et al discussed the importance of assessing this patient population for suicidal ideation, due to increased risk factors for suicidality.3 according to byne et al, up to 47% of transgender adults have considered or attempted suicide.3 • while gd may not be a trigger for substance abuse alone, the stress-related diagnoses can be a trigger. • minority stress, vulnerability, societal discrimination, identify stigmatization, and issues with access to health care can all contribute to a variety of addictive and risky behaviors.3 anesthesia ejournal www.anesthesiaejournal.com volume 7 no.4 2019 page 14 volume 10no. 4 2022 texas christian university “the science behind the art” volume 10 no.4 2022 anesthesia ejournal online issn 2333-2611 page 3 ondansetron prior to spinal anesthesia to prevent hypotension during cesarean delivery haley marie jordan, bsn, rn, rrna affiliation: texas christian university grant/financial support: none keywords: cesarean section, 5 hydroxytryptamine-3 receptor antagonist, hypotension, spinal anesthesia, bezold-jarisch reflex abstract subarachnoid blocks (sabs) are gold standard for elective cesarean sections, but this anesthetic technique commonly causes hypotension leading to undesirable effects for the mother (eg, nausea, vomiting) and baby (eg, decreased placental blood flow).9 vasoactive drugs are often administered, but this may also affect the placental blood flow.6 the purpose of this case report is to explore effects of administering ondansetron, a 5ht3 receptor antagonist, on spinal anesthesiainduced hypotension when administered prior to the sab and synthesize recent literature to make recommendations for future practice. aej about the author: haley jordan is currently a graduate nurse anesthesia student at texas christian university harris school of nurse anesthesia, class of 2022. she has obtained a bachelor of science in nursing at texas a&m university health science center, 2017. she has been a cardiothoracic and transplant intensive care unit registered nurse, primarily working at baylor university medical center, dallas, tx and mcallen heart hospital, mcallen, tx. haley is obtaining her dnp-a and will be working at baylor scott and white, temple, tx after graduation. texas christian university “the science behind the art” volume 10 no.4 2022 anesthesia ejournal online issn 2333-2611 page 4 powerpoint template ©2009 texas christian university, center for instructional services. for educational use only. content is the property of the presenter and their resources. introduction • spinal anesthesia (sa) is the standard of care for elective cesarean delivery, but consistently causes maternal hypotension from spinal-induced sympathectomy1 • maternal hypotension can have numerous undesirable effects, which can potentially lead to a cascade of issues for the mother and fetus (figure 1)1-7 • hypotension post-sa is due to sympathectomy, causing venous pooling and arterial dilation. many receptors are involved in the activation of the bezold-jarisch reflex, including 5hydroxytryptamine receptors 3 (5ht3), a serotonin-type of receptor1,8,9 • it has been theorized that utilizing a 5ht3 receptor antagonist prior to inducing sa may attenuate the bezold-jarisch reflex, decreasing the amount of hypotension1-7 • the purpose of this case study is to explore the effects of ondansetron administration prior to a subarachnoid block on spinal-induced hypotension discussion • all studies indicated that ondansetron prior to the administration of a spinal attenuate hypotension, but the degree of hypotension prevented is difficult to determine, as some studies measure hypotension alone1,4-7 and some the amount measure vasopressor consumption2,3 • ondansetron prevention of hypotension is not common knowledge, perhaps because many systematic reviews and meta-analyses have identified publication bias in the past, hindering its exposure. more recent studies have no indication of systematic bias 12 • many anesthesia providers posit ondansetron may be unsafe during pregnancy, however no adverse events reported in the literature.1-7,11 no significant major congenital malformations or adverse events with the use of ondansetron during pregnancy10,11 • the most productive method of applying this information to practice would be to educate providers of the potential benefit of administering ondansetron prior to a sab • ondansetron is not adequate to rely on as the only medication to use to prevent hypotension, just an additional medication to aid in minimizing hypotension case critique • for this case, the patient was given ondansetron 2 minutes prior to the spinal anesthetic. to follow the current literature, it would have been ideal to administer the ondansetron 5 minutes prior to the sab • the patient’s blood pressure dropped minimally and only 1.5 ml of phenylephrine (100 mcg/ml) was administered • applying this clinically may be difficult as the timing of spinal anesthesia may be difficult to predict ondansetron prior to spinal anesthesia to prevent hypotension during a cesarean delivery haley jordan, bsn, rn, texas christian university case report • 34-year-old, g3p2, 39-weeks pregnant female, ht 65 in, wt 97 kg, bmi 35.6, asa ii, scheduled for elective repeat cesarean section preanesthetic evaluation • pmh: preeclampsia with second pregnancy, but no other comorbidities; no issues this pregnancy • current medications: the patient was prophylactically on low-dose aspirin with her history of preeclampsia, but she was not preeclamptic for this pregnancy. • psh: prior cesarean section x1 • labs: cbc (wnl), urine drug screen, type and screen • medications: aspirin • premedication: 500 ml lr • anesthetic plan: subarachnoid block with nasal cannula intraoperative course • standard monitors and 2l o2 via nasal cannula. sitting for sab • pre-procedure vs: bp: 150/80 (nervous), hr: 82 • 4 mg ondansetron administered 2 minutes before 0.75% bupivacaine (1.6ml) with 0.2 mg duramorph + 15 mcg fentanyl for sab. t6 sensory block confirmed, full motor block obtained • bp 3 min post-sab: 130/65 mmhg, 6 min: 118/50 mmhg (treated with 100 mcg phenylephrine to prevent nausea). 9 min after: 125/59 mmhg. the lowest bp reading was 100/45 mmhg, which was 35 min after the sab. • total medication administration: 150 mcg phenylephrine, 800 ml lr • ebl: 800 ml postoperative course • vs: hr: bp: 122/67, hr: 75 references 1. heesen m, klimek m, hoeks se, rossaint r. prevention of spinal anesthesia-induced hypotension during cesarean delivery by 5-hydroxytryptamine-3 receptor antagonists: a systematic review and meta-analysis and meta-regression. anesth analg. 2016;123(4):977-988. doi:10.1213/ane.0000000000001511 2. qian j, liu l, zheng x, xiao f. does an earlier or late intravenous injection of ondansetron affect the dose of phenylephrine needed to prevent spinal-anesthesia induced hypotension in cesarean sections? drug design, development and therapy. 2020;14, 2789–2795. doi: 10.2147/dddt.s257880 3. tatikonda cm, rajappa gc, rath p, abbas m, madhapura m, gopal nv. intravenous ondansetron on spinal anesthesia-induced hypotension and bradycardia: a randomized controlled doubleblinded study. anesthesia, essays and researches. 2019;13(2), 340–346. doi: 10.4103/aer.aer_22_19 4. abbas n, shah s, naqvi s. role of prophylactic ondansetron for prevention of spinal anesthesia induced hypotension in lower segment cesarean section. pafmj. 2016;66(6), 790-94. 5. owczuk r, wenski w, twardowski p, dylczyk-sommer a, et al. ondansetron attenuates the decrease in blood pressure due to spinal anesthesia in the elderly: a double blind, placebocontrolled study. minerva anestesiologica. 2015;81(6), 598–607 6. owczuk r, wenski w, polak-krzeminska a, et al. ondansetron given intravenously attenuates arterial blood pressure drop due to spinal anesthesia: a double-blind, placebo-controlled study. reg anesth pain med. 2008;33(4):332-339. doi:10.1016/j.rapm.2008.01.0 7. gao l, zheng g, han j, wang y, zheng j. effects of prophylactic ondansetron on spinal anesthesiainduced hypotension: a meta-analysis. international journal of obstetric anesthesia. 2015;24(4), 335–343. https://doi.org/10.1016/j.ijoa.2015.08.012 8. warltier dc, campagna ja, carter c. clinical relevance of the bezold–jarisch reflex. anesthesiology. 2003;98(5):1250-1260 9. raju s, kapoor a. illustrated medical pharmacology. 1st ed. jaypee digital; 2013; 1(16). doi: 10.5005/jp/books/12078_29 10. bérard a, sheehy o, gorgui j, jin-ping z, cristiano soares dm, bernatsky s. new evidence for concern over the risk of birth defects from medications for nausea and vomiting of pregnancy. j clin epidemiol. 2019;116:39-48 11. suarez ea. use of ondansetron for nausea and vomiting during pregnancy and adverse pregnancy outcomes. the university of north carolina at chapel hill; 2019 12. tubog t, kane t, pugh m. effects of ondansetron on attenuating spinal anesthesia–induced hypotension and bradycardia in obstetric and non-obstetric subjects: a systematic review and metaanalysis. aana journal. 2017;85 (2). conclusions & practice recommendations • consider 4 mg ondansetron administration prior to spinal insertion to improve bp and decrease vasopressor use during elective cesarean section • ondansetron administration as a sole intervention may not be ideal, so use as an adjunct in a multimodal approach to decreasing overall maternal hypotension • protocol implementation may be excessive evidence utilization. however, dissemination of information and education regarding ondansetron prior to sab may lead to increased use by anesthesia providers and leading to further research.background of the bezold-jarisch reflex with spinal anesthesia • after local anesthetic is injected into the subarachnoid space, a sympathetic blockade occurs 2-6 dermatomes above the sensory blockade8 • the sympathectomy causes arterial dilation and venous pooling, causing decrease blood return to the heart. baroreceptors initially sense the decrease in blood pressure, decreasing their rate of fire to the vasomotor center of the medulla. a sympathetic response occurs1,2,3,8,9 • the contraction of a poorly filled ventricle activates mechanoreceptors and chemoreceptors • the 5ht-3 receptors are among the chemoreceptors involved in transmission of signals to the vasomotor center. this receptor is not the typical g-protein coupled serotonin receptor. this receptor is a ligand-gated ion channel that produces effects much more rapidly1,8 • when activated, the 5ht3 receptor signals the vasomotor center to activate the bezold-jarisch reflex via unmyelinated c-fibers8,9 • the bezold-jarisch reflex is cardioinhibitory and causes an increase in parasympathetic activity, which leads to bradycardia, increased venous pooling, and hypotension (figure 2)1,2,8,9 • studies have been conducted to evaluate the effects of ondansetron, a 5ht3 antagonist, on reducing the amount of hypotension seen with a spinal anesthetic1-7 figure 2. depiction of bezold-jarisch reflex9 figure 1. potential cascade of events during maternal hypotension1-7 volume 12no. 2 2024 texas christian university “the science behind the art” volume 12 no.2 2024 anesthesia ejournal online issn 2333-2611 page 9 occupational turnover factors for certified registered nurse anesthetists: a scoping review michael c. lambert1, robyn c. ward2, and dru riddle3 1. harris college of nursing & health sciences phd program, texas christian university 2. school of nurse anesthesia, texas christian university 3. school of nurse anesthesia, texas christian university grant/financial support: none keywords: job satisfaction; occupational stress; organizational climate; organizational commitment; turnover intention abstract the objective of this scoping review is to understand the extent and type of evidence related to occupational turnover factors for certified registered nurse anesthetists (crna) in the united states. demand for anesthesia services is increasing dramatically. crnas provide a significant number of anesthetics each year and are crucial to accessible anesthesia in the u.s. understanding occupational turnover factors for crnas is vital to providing cost effective, reliable anesthesia services for americans. studies relevant to crna turnover in the u.s. were included for this review. due to differences in education, scope of practice, and practice environment, studies involving nurse anesthetists outside the u.s. were excluded. studies with mixed provider populations including physicians, registered nurses, other advanced practice providers, and students were also excluded. five studies were included for data extraction. all the studies employed electronic or mailed questionnaires. common factors associated with occupational turnover were compensation, retirement, job satisfaction, and burnout. findings suggest that occupational turnover factors are multifactorial and include broad concepts such as job satisfaction, burnout, and organizational climate. aej introduction according to the u.s. bureau of labor statistics1, demand for advanced practice nurses, including certified registered nurse anesthetists (crna), is projected to increase by 45% between 2020 and 2030. in the u.s., crnas deliver upwards of 50 million anesthetics annually and are vital to accessible anesthesia services2. in the aftermath of the sars-cov-2 (covid-19) pandemic, resignations among healthcare providers have reached unprecedented levels3. given the tremendous cost of occupational turnover (hereafter referred to as turnover) in healthcare4, as well as evidence that turnover impacts the quality of healthcare delivery5, exploring the evidence related to turnover factors for crnas is important. a preliminary search of medline complete and embase was conducted and no current or underway systematic reviews or scoping reviews on the topic were identified. results of the preliminary search indicated literature on the topic that met inclusion criteria and justified conducting a review. exploring the available evidence in a scoping review format was deemed appropriate given the body of literature specific to crnas. the objective of this scoping review is to understand the extent and type of evidence in relation to turnover factors for crnas in the u.s. review question what factors are associated with turnover for crnas in the u.s.? eligibility criteria participants of interest for this scoping review are crnas in the u.s. no exclusion criteria were set for demographic variables such as gender, age, practice type, or geographical location within the u.s. if the study focused on practicing crnas in the us, it was eligible for inclusion. exclusion criteria in the participant realm included studies focusing on a mix of provider type. for example, studies were identified that included data related to turnover for physicians and crnas. to keep within the boundaries of the objective for this study, literature including physicians, advanced practice providers other than crnas, registered nurses (rn), and students were excluded.  concept occupational turnover is the conceptual foundation for this review. hanisch and hulin6 conceptualized turnover as voluntary employee withdrawal from an organization. turnover intention is also included as a concept as it is correlated with turnover behavior7. turnover intention varies from turnover in that the latter is defined by the behavior of voluntary organizational withdrawal, while the former is a cognitive intention8. research has shown that turnover intention accounts for 9%-25% of turnover7,9. given the correlation between turnover intention and turnover, studies addressing turnover and turnover intention for crnas were eligible for inclusion. in the literature, turnover and turnover intention have been linked with a variety of factors. occupational stress, job satisfaction, burnout, organizational climate, and workplace civility are examples of factors that have been linked to turnover10,11,12,13. literature focusing on factors outside of turnover, while maintaining some connection to turnover, were excluded to maintain fidelity to the objective of this review.  context contextual inclusion criteria for this literature review were limited to the study setting being in the u.s. for this scoping review, “crnas” refers to nurse anesthetists practicing in the u.s., and “nurse anesthetists” refers to nurse anesthetists internationally. preliminary review of the literature identified significant differences between crnas and nurse anesthetists in other countries. examples of some of those differences are degree of training, scope of practice, and role overlap with physicians delivering anesthesia. given that turnover factors for nurse anesthetists might not universally apply, studies addressing turnover and turnover intention in nurse anesthetist populations outside of the u.s. were excluded. dissemination date was considered as an eligibility criterion, but no limitations were set on date of publication. given the relative newness of the nurse anesthesia profession, any article related to turnover factors for crnas was considered for inclusion.  types of sources this scoping review considered both experimental and quasiexperimental study designs including randomized controlled trials, non-randomized controlled trials, before and after studies and interrupted time-series studies. in addition, analytical observational studies including prospective and retrospective cohort studies, case-control studies and analytical cross-sectional studies were considered for inclusion. this review also considered descriptive observational study designs including case series, individual case reports and descriptive cross-sectional studies for inclusion. qualitative studies were considered that focus on qualitative data including, but not limited to, designs such as phenomenology, grounded theory, ethnography, qualitative description, action research and feminist research. in addition, systematic reviews that met the inclusion criteria were also considered, depending on the research question. text and opinion papers were not considered for inclusion in this scoping review. the rationale here was preliminary review of the literature indicated a sufficient research-based body of literature to exclude text and opinion papers. methods the proposed scoping review was conducted in accordance with the jbi methodology for scoping reviews14. search strategy the search strategy’s aim was to locate published studies. an initial limited search of medline complete and embase was undertaken to identify articles on the topic. the text words contained in the titles and abstracts of relevant articles, and the index terms used to describe the articles were used to develop a full search strategy for medline complete and embase. keywords for the search included nurse anesthetist, crna, burnout, job satisfaction, occupational stress, turnover, turnover intention, intent to quit, moral injury, moral distress, job retention, and job engagement. the search strategy, including all identified keywords and index terms, was adapted for each texas christian university “the science behind the art” volume 12 no.2 2024 anesthesia ejournal online issn 2333-2611 page 10 included database and information source. the reference list of all included sources of evidence were also screened for additional studies. studies published in english were included. no date range limitations were set for study inclusion. databases searched include medline complete and embase. study/source of evidence selection following the search, all identified citations were collated and uploaded into endnote 20.4.1/2021 (clarivate analytics, pa, usa) and duplicates removed. following a pilot test, titles and abstracts were then screened independently by each of the authors for assessment against the inclusion criteria for the review. potentially relevant sources were retrieved in full. the full text of selected citations was assessed in detail against the inclusion criteria by each of the authors. reasons for exclusion of sources of evidence at full text that did not meet the inclusion criteria were recorded and are reported below. any disagreements that arose between the reviewers at each stage of the selection process was resolved through discussion. data extraction data was extracted from papers included in the scoping review by two independent reviewers using the joanna briggs institute ( jbi) scoping review data extraction template15. the data extracted included specific details about the participants, concept, context, study methods and key findings relevant to the review questions. methodological quality or risk of bias was not appraised, consistent with guidelines for scoping review conduct16. results initial results of the search returned a total of 508 items. after removal of duplicates, 317 articles were screened. 247 articles were excluded as not related based on appraisal of title or abstract. 70 articles were obtained in full for review. of the 70, 34 articles were excluded due to a focus on nurse anesthetists outside of the u.s. of the remaining 36, 22 were excluded after review of the full text due to not relating to turnover factors. 9 articles were excluded after review, due to either the inclusion of other types of providers or focusing on factors loosely related to turnover (eg, occupational stress or job satisfaction). in total, five articles underwent data extraction for inclusion in this review. characteristics of sources of evidence three of the articles were disseminated between 2020 and 202217,18,19. one was published in 200720, with the final article being published in 199021. four of the five studies were based on data obtained from mailed or electronic surveys18,19,20,21, with one being secondary analysis of data collected via electronic survey17. all the studies were based in the u.s., dealt with turnover and/ or turnover intention, and the studied population was limited to practicing crnas. two of the studies included data from crnas across the u.s.17,19, two were limited to geographical regions in the u.s.18,21, with one being limited to crnas practicing in the department of veterans affairs20. factors associated with turnover and turnover intention each article presented factors associated with turnover and or turnover intention differently. factors are presented here in order of number of articles associating it with turnover. this order is not intended to indicate ranking or level of importance as not each article ranked factors in terms of impact on turnover or turnover intention. turnover factors for crnas most frequently cited in the literature included for this review were compensation, retirement, job satisfaction, and burnout. compensation was a factor associated with turnover or turnover intention in each of the articles17,18,19,20,21. “better pay” was the terminology used in three of the studies17,18,19, with “pay satisfaction”21 and “non-competitive salaries”20 being other terms used. compensation was the only factor identified in each of the articles. retirement as a factor for turnover or turnover intention was identified in four of the articles17,18,19,20. job satisfaction was associated with turnover in three of the articles18,19,21. burnout was identified as a factor in turnover, or turnover intention, in three of the articles17,18,19. career advancement as a factor for turnover was identified in three of the articles17,19,21. the terminology associated with career advancement varied, with the following terms being represented in the studies included in this review: “promotion” and “career advancement”17, “advance position”19 (as a reason for leaving), and “promotion satisfaction”21. better working conditions was identified as a factor for turnover in two of the articles18,19. finally, geographic relocation was listed as a factor for turnover in two articles17,19. other factors associated with turnover and/or turnover intention were more specific and did not share categorization similarities between studies. the list of all these factors is too broad to incorporate here, but examples are role ambiguity and role restraints, incompetent leadership, limited scope of practice, dissatisfaction with schedule, stressful work environment, and inadequate staffing17,19. broader concepts like job satisfaction and burnout were also associated with turnover19. discussion the major finding of this scoping review is that turnover factors for crnas are multifactorial. compensation, retirement, job satisfaction, burnout, career advancement, and geographic relocation were cited across the literature as turnover factors for crnas in the u.s. however, this evidence indicates that not just one of the above factors alone is responsible for turnover or turnover intention in crnas. for example, dexter et al17(p487) found that crnas who had left their position provided 2.5 “primary” reasons for quitting, and crnas who had considered leaving their positions had an average of 3.7 primary reasons. another finding of this scoping review is that the broad concepts of job satisfaction and burnout have a multitude of indicators that impact turnover and turnover intention. mahoney et al19 found that burnout and job satisfaction were determined by job and personality characteristics. examples of some of those characteristics were autonomy, skill variety, agreeableness, age, and hours worked per week. lea et al18 reported that burnout was associated with a decrease in job satisfaction, which contributed to turnover intention. factors identified by lea et al18 as contributing to burnout were job feedback (more feedback decreasing burnout), crna and administration relations (better relations decreasing burnout), and work and personal responsibility conflicts (conflicts resolved in favor of work increasing burnout). texas christian university “the science behind the art” volume 12 no.2 2024 anesthesia ejournal online issn 2333-2611 page 11 organizational climate is another concept that deserves mention. lea et al18 and szigeti et al21 both mention organizational conditions or climate as a factor in turnover. sein myint et al22(p175) define organizational climate as, “a shared perception about an organization by its workforce”. lea et al18(p145) tie this concept into turnover in the following statement, “the degree to which an organizational climate values, supports, communicates, and collaborates with crnas was a significant predictor of burnout and resultant changes in job satisfaction and turnover intention”. szigeti et al21(p324) state, “the organizational or work conditions variables—i.e., role ambiguity, opportunity to participate, and performance constraints—were moderately related to intention to quit”. what these statements suggest is that the concept of organizational climate, with its varied indicators, plays a role in turnover intention. these findings have implications for practice. perhaps the biggest implication for practice is that preventing turnover requires a multifaceted approach from organizations. to synthesize the findings into practice implications, categorization of the myriad factors might be useful. for example, retirement and geographical relocation could be categorized as personal factors. factors such as better pay, career advancement, job satisfaction, and burnout could be categorized under the umbrella concept of organizational climate. even though organizations might not ultimately be able to prevent attrition secondary to personal factors (i.e., retirement or employees choosing to relocate), this evidence suggests that efforts to ensure competitive compensation, and an organizational climate that minimizes burnout and maximizes job satisfaction, are valuable considerations to mitigate turnover. these findings are also useful as they suggest future directions for research. exploring the overlap between the concepts of job satisfaction, burnout, and organizational climate would help define conceptual boundaries and areas of overlap, as well as elucidate their relationship with turnover. to our knowledge, no qualitative studies have been conducted on turnover and turnover intention for crnas in the u.s. qualitative research, with its exploration of the lived experience of participants, may be useful in providing a more textured understanding in this area. this scoping review is not without limitations. first, the studies included in this review used disparate approaches to address factors associated with turnover, thus, the findings are not generalizable beyond the scope of the initial study. second, crna populations studied in this body of literature varied, resulting in findings that may not apply to crnas in the u.s. at large. finally, all but one of the studies18, was based on data collected prior to the covid-19 pandemic, the impact of which on turnover in healthcare is still an area of active research, and thus may not reflect covid-19 associated factors involved in the unprecedented turnover currently being experienced in healthcare. conclusion the objective of this study was to explore the extent and type of literature related to turnover factors for crnas in the u.s. to that end, this scoping review found that turnover factors for crnas are myriad, with compensation, retirement, job satisfaction, and burnout being the most frequently mentioned factors in the literature included for this review. broad concepts such as burnout, job satisfaction, and organizational climate were also associated with turnover in this body of literature. the broad nature of these concepts, with overlap between them, suggest the value of future research in this area. qualitative research in this area might also be of value in addressing gaps in the qualitative body of literature. finally, practice implications from this scoping review indicate that organizational efforts in the areas of competitive compensation and a positive organizational climate may be rewarded with a decrease in turnover for crnas they employ. texas christian university “the science behind the art” volume 12 no.2 2024 anesthesia ejournal online issn 2333-2611 page 12 references 1. bureau of labor statistics, u. s. department of labor. nurse anesthetists, nurse midwives, and nurse practitioners. occupational outlook handbook web site. https://www.bls.gov/ooh/healthcare/nurse-anesthetists-nurse-midwives-and-nurse-practitioners. htm. accessed august 18, 2022. 2. american association of nurse anesthesiology. certified registered nurse anesthetists fact sheet. https://www-aana-com. ezproxy.tcu.edu/membership/become-a-crna/crna-fact-sheet#:~:text=prolific%20providers%3a%20crnas%20are%20 anesthesia,trusted%20professions%20according%20to%20gallup. updated 2022. accessed august 18, 2022. 3. bureau of labor statistics, u. s. department of labor. number of quits at all-time high in november, 2021. the economics daily web site. https://www.bls.gov/opub/ted/2022/number-of-quits-at-all-time-high-in-november-2021.htm. accessed august 18, 2022. 4. waldman jd, kelly f, arora s, smith hl. the shocking cost of turnover in health care. health care management review. 2004;29:2-7. 5. zaheer s, ginsburg l, wong hj, thomson k, bain l, wulffhart z. acute care nurses’ perceptions of leadership, teamwork, turnover intention and patient safety a mixed methods study. bmc nursing. 2021;20(1):1-134. 6. hanisch ka, hulin cl. general attitudes and organizational withdrawal: an evaluation of a causal model. j vocat behav. 1991;39(1):110-128. 7. cho yj, lewis gb. turnover intention and turnover behavior: implications for retaining federal employees. review of public personnel administration. 2012;32(1):4-23. 8. tett rp, meyer jp. job-satisfaction, organizational commitment, turnover intention, and turnover path analyses based on metaanalytic findings. person psychol. 1993;46(2):259-293. 9. dalton dr, johnson jl, daily cm. on the use of “intent to...” variables in organizational research: an empirical and cautionary assessment. human relations (new york). 1999;52(10):1337-1350. 10. alves sl. a study of occupational stress, scope of practice, and collaboration in nurse anesthetists practicing in anesthesia care team settings. aana j. 2005;73(6):443-452. 11. boyd d, poghosyan l. measuring certified registered nurse anesthetist organizational climate: instrument adaptation. j nurs meas. 2017;25(2):224-237. 12. elmblad r, kodjebacheva g, lebeck l. workplace incivility affecting crnas: a study of prevalence, severity, and consequences with proposed interventions. aana j. 2014;82(6):437-445. 13. thompson l. job satisfaction of nurse anesthetists. aana j. 1981;49(1):43-51. 14. tricco ac, lillie e, zarin w, et al. prisma extension for scoping reviews (prisma-scr): checklist and explanation. ann intern med. 2018;169(7):467-473. 15. joanna briggs institute. jbi manual for evidence synthesis. jbi web site. https://synthesismanual.jbi.global/. updated 2022. accessed august 26, 2022. 16. peters mdj, marnie c, tricco ac, et al. updated methodological guidance for the conduct of scoping reviews. jbi evidence synthesis. 2020;18(10):2119-2126. 17. dexter f, epstein r, elhakim m, o’sullivan c. us survey of incidence of and reasons for nurse anesthetists leaving or having considered leaving their jobs. aana j. 2021;89(6):484-490. 18. lea j, doherty i, reede l, mahoney cb. predictors of burnout, job satisfaction, and turnover among crnas during covid19 surging. aana j. 2022;90(2):141-147. 19. mahoney cb, lea j, schumann pl, jillson ia. turnover, burnout, and job satisfaction of certified registered nurse anesthetists in the united states: role of job characteristics and personality. aana j. 2020;88(1):39-48. 20. united states. government accountability office. va health care: many medical facilities have challenges in recruiting and retaining nurse anesthetists : report to congressional requesters. 2007. https://go.exlibris.link/wgcrcprg. texas christian university “the science behind the art” volume 12 no.2 2024 anesthesia ejournal online issn 2333-2611 page 13 21. szigeti e, largent rn, eberhardt bj. an exploratory study of the correlates of intent to quit among certified registered nurse anesthetists in north dakota. the journal of rural health. 1990;6(3):317-327. 22. sein myint nn, kunaviktikul w, stark a. a contemporary understanding of organizational climate in healthcare setting: a concept analysis. nursing forum (hillsdale). 2021;56(1):172-180. appendices figure 1: prisma diagram from: page mj, mckenzie je, bossuyt pm, boutron i, hoffmann tc, mulrow cd, et al. the prisma 2020 statement: an updated guideline for reporting systematic reviews. bmj 2021;372:n71. doi: 10.1136/bmj.n71 anesthesia ejournal online issn 2333-2611 page 14 texas christian university “the science behind the art” volume 12 no.2 2024 records identified from: databases (n = 508) registers (n = 0) records removed before screening: duplicate records removed (n = 191) records screened (n = 317) records excluded based on abstract or title relevance (n = 247) reports sought for retrieval (n = 70) reports not retrieved (n = 0) reports assessed for eligibility (n = 70) reports excluded (n = 65) specific to international nurse anesthetists (n = 34) not related to occupational turnover factors (n = 22) mixed provider studies or related to loosely related factors (n = 9) studies included in review (n = 5) appendix 2 table 1. factors associated with crna occupational turnover study factors dexter et al, 202117 better pay/benefits, burnout, lack of good management/ leadership, inability to practice to the full extent of my license, retirement, scheduling, interpersonal differences, stressful work environment, promotion, inadequate staffing, geographic relocation, lack of advancement opportunities, career change, physical demands of the job leah et al, 202218 burnout, job satisfaction, better working conditions, better pay, retirement mahoney et al, 202019 better working conditions, retirement, better pay, geographic relocation, promotion, job satisfaction, burnout united states, government accountability office, 200720 salaries not competitive szigeti et al, 199021 overall satisfaction, pay, promotion, role ambiguity, role constraints anesthesia ejournal online issn 2333-2611 page 15 texas christian university “the science behind the art” volume 12 no.2 2024 volume 10 no. 2 2022 texas christian university “the science behind the art” volume 10 no.2 2022 anesthesia ejournal online issn 2333-2611 page 1 barriers and determinants that influence membership in the american association of nurse anesthesiology david samons, dnap, crna affiliation: adventhealth university school of nurse anesthesia graduate, orlando, florida jissel samons, dnap, crna affiliation: adventhealth university school of nurse anesthesia graduate, orlando, florida manuel tolosa, dnap, crna affiliation: department vice-chair and assistant program administrator of adventhealth university grant/financial support: none keywords: membership, nonmembers, aana, professional association, crna abstract the american association of nurse anesthesiology (aana) has a significant role in providing various benefits to members and advancing the profession. however, membership percentages have decreased within the last 10 years. a review of the literature discovered florida was among the states with the highest percentages of nonmembers. a scholarly project online survey was developed and sent to all florida certified registered nurse anesthetists (crnas) with the help of the florida association of nurse anesthesiology (fana). the results of the survey revealed barriers to member-ship included dissatisfaction with the new national board of certification and recertification for nurse anesthetists (nbcrna) continued professional certification (cpc) requirements, cost of membership, and a lack of education about the aana. determinants to membership identified included the benefit of ceus and tracking, professional promotion, and the aana’s political advocacy. sufficient information was derived to suggest implications and recom-mendations to help improve future research efforts and better understand the issue. aej texas christian university “the science behind the art” volume 10 no.2 2022 anesthesia ejournal online issn 2333-2611 page 2 membership in professional associations has a significant role in providing various benefits to their members as well as the protection and advancement of the profession. benefits include advancing professional knowledge, establishing a code of ethics and standards of practice, promoting professional growth and development, and providing networking opportunities.1,2 for these reasons, professional associations exist in almost every field of study.3 in addition, members who are affiliated with a professional organization feel a sense of belonging and build interpersonal relationships with others involved in the group.2 joining a professional association was part of one’s duty and responsibility in previous years. over time, focus has shifted to personal interest as a primary reason for joining.2 currently, there is evidence of a widespread decrease in the number of members, member involvement, and retention within professional organizations.1,2,4 one organization of particular interest for this scholarly dnap project is the american association of nurse anesthesiology (aana). problem description aana national data report,5 the total number of certified registered nurse anesthetists (crna) has grown by 16,905, representing a 46.3% increase from 2008 to 2018. however, the total number of crnas who are aana members increased by only 34.6% within that same 10-year period.5 membership with the aana allows the organization to continue to provide education, guidance, and fight to maintain and further the scope of practice for crnas. therefore, a professional organization is not only beneficial to its members but also helps the profession to evolve. the state of florida is of special interest and is one of the states with the most crnas but has one of the highest non-membership percentages.1 the national average for nonmembers in 2018 was around 12%.5 the percentage of nonmembers in florida was 20.7% in 2016 and increased to 26% in 2018. 1,5 understanding the factors that determine member participation is crucial to ensure satisfied members and professional growth. this can be accomplished by using a survey to help gain insight into the elements that lead to retention and future involvement by crnas within their professional organization. picot search format questions two questions were developed in picot format to assist in a systematic review of the literature. the first question addressed the problem question: pfor licensed certified registered nurse anesthetists (crnas), iwhat are barriers and determinants, othat influence decisions to become or remain involved within their professional organization, tpost-graduation? a second picot question was developed to address a possible innovation for fana: pfor florida licensed certified registered nurse anesthetists (crnas), iwhat are barriers and determinates, othat influence involvement for members and nonmembers within the american association of nurse anesthesiology (aana), tpost-graduation? project aims the purpose of this scholarly project was to examine the factors that influenced decision-making regarding professional association membership among florida’s licensed nurse anesthetists using an online survey. a secondary aim was to delineate the barriers and determinants of licensed nurse anesthetists residing in the state of florida to become or remain members of national and state professional organizations. results were disseminated to the state organization and recommendations suggested to fana. search strategy the search strategy included pubmed and google scholar databases. a total of 917 articles were screened according to the title, inclusion, and exclusion criteria. articles were excluded from the review if they were over 10 years old, pertained to non-professional associations, and if the type of research was not described in the article. of these, 10 research articles pertaining to nurses, pharmacy, dentistry, chiropractors, and occupational therapists were retained for review. key search terms included: “aana membership,” and “professional organization membership,” and “professional association membership.” mesh terms included: professional organization, nurse anesthetist, crna, membership, students, and professional associations. the search limits that were used: within the last 10 years and in the english language. grade criteria grading of recommendations, assessment, development, and evaluation (grade) criteria were used to rate the literature collected. the working group developed grade in 2000 to address the shortcomings of grading systems in healthcare. it has been used internationally and considered the standard in guideline development.6 the grade scale ranges from 1 – 9 where the lower numbers represent limited importance for guiding decisions. higher numbers represent more critical importance for guiding decisions. the literature reviewed primarily comprised qualitative studies (lower grade scores). however, many of the studies used quantitative measurements for qualitative data using number scales to give partial qualitative answers. this enabled statistical analysis and a more thorough understanding of data raising the grade score up to 4. inconsistent control of duplicate survey responses, low survey responses and inconsistent data validation downgraded grade scoring to 2. publication bias was ruled out because the studies’ results would not have benefited the researchers or publishers. the greatest concern in this literature review was the lack of research specific to nurse anesthesia professional organizations. overall, the quality of the data collected was low, which further justified the need to conduct the scholarly project. literature review and synthesis of evidence review of the literature was performed to identify barriers and determinants that influence membership within the aana. data were limited specific to nurse anesthetist’s professional organizations, however, common themes and results emerged throughout the literature: benefits of professional membership, methods used to collect data, reasons why professionals do or do not join their professional organization, and involvement within the professional organization. texas christian university “the science behind the art” volume 10 no.2 2022 anesthesia ejournal online issn 2333-2611 page 3 benefits of professional membership being a member of one’s respective professional organization were very consistently deemed beneficial.1,4,13-15 professional organizations also were reported to advance development of the professional, encourage leadership, advocate for members, influence policy, provide continuing education, provide a source of networking, and provide members a sense of belonging and identity.1,4,13-15 in general, membership was mutually beneficial for the individual as well as the profession. despite the abundance of benefits that professional memberships offer, the percentages of memberships have been steadily decreasing with the newest members least likely to join.1,4,13,14-17 data collection methods several common methods were used to collect data in the literature reviewed: interviews, questionnaires, and online surveys. interviews although thorough and effective (phone or in-person) were cited to limit data collection due to time and yielded smaller sample sizes limiting generalization of results.1,13 survey data could have offered researchers a feasible option to reach larger populations in less time, but also risked individuals completing more than one survey and offered low response rates.2-4,14-17 posting the survey on the professional organization’s webpage or social media account did improve response percentages.4,15,18 reasons to join professional organizations the most common reasons for joining a professional organization were networking opportunities, organizational support, individual professional development, professional identity promotion, and a sense of belonging. getting free continuing education credits was also a major reason why professionals chose to join or renew membership.1,4,13,15. the most common and significant reason for not joining was membership cost.1,4,13-15 other common reasons included lack of time, lack of benefits, poor service, inconvenience, and poor value for the cost involved.4,14,15 it is also important to note that some nonmembers surveyed possessed a poor understanding of what professional organizations offer.1,4,15,18 according to farina,1 an individual’s perception of value was the key determinant for membership. professional organization involvement the literature indicated membership and involvement within the professional organization have declined.16,17 professional involvement included mentoring colleagues, advocating for the profession, e-mailing senators, attending state and national conferences, and becoming politically active. 2,16,17 if the trend continues, fewer professionals will be involved in advocating for the profession. the potential reasoning behind the declining number of professionals involved within their professional organization or being politically active was education about impact of involvement and what the organization gives to members.2,17 plan, do, study, act (pdsa) cycle understanding the factors that can improve membership percentages within the aana is crucial to reverse the downward trend. theoretical frameworks and conceptual models help guide and organize projects to successful completion. one model is the plan, do, study, act (pdsa) cycle. this model provides a framework with 4 stages to help lead to improvement.19 the “plan” stage involves identifying the problem to be improved, creation of picot questions, review of literature, assembling a project committee, and developing the implementation tool. the “do” stage is the implementation phase depicted by fana deploying an online survey. the “study” stage involves analyzing the data to identify key findings to meet the scholarly project’s objectives. the last stage is “act.” during this stage, recommendations are made and disseminated based on the findings of the scholarly project. methods the scholarly project design was a mixed-methods design that used descriptive statistics to describe qualitative and quantitative data. the sample methodology was a purposive sampling method directed to florida’s licensed nurse anesthetists. a survey was the most logical and feasible method to collect data from a large population for this scholarly project; it was also the most frequently used method found in the literature reviewed. the project’s data collection tool was a survey that used likert scale questions to capture quantitative data. the survey also had open-ended fill-in-the-blank options to capture qualitative data. a validated survey for the data collection tool was the original goal. however, there was a problem finding a validated survey that was unique and specific to the topic’s population; after further review and contacting the aana and fana’s research department, creating an online survey specific to this target population that stems from current validated surveys was deemed the best and most reliable way to achieve desired results. a survey was created and face-validated by three adventhealth university (ahu) doctorate nurse anesthesia program (dnap) students, one end-user crna, two dnap faculty members, one ahu faculty member outside of the dnap department, and the president of fana. the survey underwent pilot testing through surveymonkey® to ensure all aspects of the survey were working. once the institutional review board (irb) of ahu approved the scholarly project, fana dispersed the survey link in a recruitment e-mail. the survey was sent out on april 1st, 2020 and was open for 30 days. completion of the online survey would take approximately 15 minutes using a mix of likert-type scale questions and short open-ended questions. the survey included demographic questions to assist in identifying members versus nonmembers. inclusion criteria included all crnas who lived in the state of florida and had a valid e-mail on file with the national board of certification and recertification for nurse anesthetists (nbcrna) who were willing to agree to the terms of the survey. original population size was 4,180 florida crnas, according to the most recent data received by fana. however, fana sent the survey out to 4,500 members and 1,700 nonmembers. exclusion criteria included crnas under 18, people who were not florida licensed nurse anesthetists, and crnas who did not have a valid e-mail on file. consent was obtained and approved by the institutional review board of adventhealth university. participants were not compensated individually but were given a chance to win one of 10 amazon $50 gift cards by entering their e-mail at the end of the survey. demographic data were summarized using frequency counts and percentages. descriptive analysis was used to compare texas christian university “the science behind the art” volume 10 no.2 2022 anesthesia ejournal online issn 2333-2611 page 4 group summaries and trends. for open-ended responses, an iterative narrative review seeking keywords, concepts, and emergent themes was used. originally, chi-square tests would be used to compare distributions of responses between members and nonmembers. however, this was not possible due to the low response rate from nonmembers. the sample size was determined at n=73 with values of power at .90 and alpha at .05 level of confidence (xlstat v. 2017). results fana sent out the survey to 6,200 recipients, and a total of 237 participants submitted a survey for a response rate of 3.82%. there were 11 (4.64%) incomplete responses that were removed from the data set. an additional 13 (5.48%) responses were also removed because fana identified them as a student registered nurse anesthetist (srna), or the respondent could not be identified. this cull left a final sample size of 213 responses. out of the 213 respondents, 88.7% (n=189) were members, 10.3% (n=22) were nonmember, and 0.09% (n=2) did not answer the question. figure 1. percentage of florida crna members and nonmembers by years of experience. texas christian university “the science behind the art” volume 10 no.2 2022 anesthesia ejournal online issn 2333-2611 page 5 figure 2. level of education completed by florida crnas. texas christian university “the science behind the art” volume 10 no.2 2022 anesthesia ejournal online issn 2333-2611 page 6 quantitative data due to the great discrepancy between the member and nonmember group sizes, statistical tests comparing the 2 groups were not plausible. the quantitative data received was used for descriptive analysis to compare group summaries and trends among members and nonmembers. figure 3. factors influencing florida crnas to join aana nonmembers were asked about top 3 factors that influenced their decision not to join. the most frequently chosen answers were the cost of membership (n=14), poor value for the cost of membership (n=11), and disagreement with aana policies and positions (n=8). this is shown in figure 4. texas christian university “the science behind the art” volume 10 no.2 2022 anesthesia ejournal online issn 2333-2611 page 7 figure 4. factors influencing florida crnas not to join aana. data also showed 12.2% (n=26) of members were not aware that being a member of the aana made them a member of fana. for the participants that were aware, the data did not show any outliers for potential barriers or determinants that influence membership. participants were also given the opportunity the choose the main source of where they received information and education about the aana (figure 5). the most frequent choices were aana journal with 39.3% (n=83) and social media platforms with 31.8% (n=67) figure 5. source of information regarding the aana each member (n=189) was asked to rate how satisfied they were with their aana membership on a 4-point likert scale (4=strongly agree, 1=strongly disagree). the results yielded an average of 3.09. this is displayed in figure 6. when asked about if they were planning to renew their membership, 89.2% (n=165) selected yes, 2.2% (n=4) selected no, and 8.6% (n=16) selected undecided. texas christian university “the science behind the art” volume 10 no.2 2022 anesthesia ejournal online issn 2333-2611 page 8 figure 6. florida crnas membership satisfaction. membership satisfication i am aware of how my aana membership dues are divided i feel valued by my professional organization (aana) the cost of aana dues for membership is worth the investment my nurse anesthesia educational program educated me on the function, role, purpose and benefits of being a member of the aana. i am satisfied with how the aana advocates at the federal level i am satisfied with the educational opportunities provided by the aana the aana is dedicated to my professional development i am aware of what the aana does for nurse anesthesia profession 0 0.5 1 1.5 2 2.5 3 3.5 4 3.02 3.04 3.04 3.12 3.24 2.97 3.28 3.45 qualitative analysis a total of 5 open-ended survey questions enabled an iterative narrative review to be conducted. these questions allowed the participants to choose the answers listed or fill in additional answers to the questions. the themes that were identified included benefits that members are dissatisfied with, additional factors that influence florida crnas to join the aana, and factors that influence florida crnas not to join the aana. benefits that dissatisfied members. the first theme that emerged frequently was issues surrounding the national board of certification & recertification for nurse anesthetists (nbcrna). participants received the option to type in additional dissatisfactions. the most frequent response was that most members were not dissatisfied with any of the benefits. other responses included continuing education units (ceu) tracking, and insurance. a subtheme that emerged quite frequently were issues with the nbcrna. while it is not a benefit, several members identified dissatisfaction with the nbcrna continued professional certification (cpc) program for continued certification. some of the quotes included “recertification changes,” “having to retake boards,” “allowing nbcrna to take over certification,” “cpc exam,” and “keeping informed about retaking boards & re-education to prepare.” some responses showed dissatisfaction with support from aana about the nbcrna. this was identified by comments such as “disagree with nbcrna. no support by aana” and “the aana/fana has not stood up for crnas against the draconian nbcrna cpc requirements.” additional factors that influenced florida crnas to join aana. the most frequent was continuing education units (ceus). the theme of political advocacy was identified as a re-occurring response by members. some of the comments included “political advocacy,” “to support our voice as crnas,” and “most importantly by far, i’m a contributing donor to the aana & fana pac.” it was also very intriguing to see this answer several times, considering the other option choices. for example, members had the option to choose personal professional development and promotion of the profession. these were two of the top three answers chosen and could be associated with political advocacy. however, members purposely decided to take the time to type in those additional responses. texas christian university “the science behind the art” volume 10 no.2 2022 anesthesia ejournal online issn 2333-2611 page 9 factors that influenced florida crnas not to join aana. out of the 22 nonmember participants, 5 typed in additional responses. three of those responses addressed dissatisfaction with support from aana and/or with the nbcrna. this was identified with comments such as “disagree with nbcrna. no support by aana” and “the aana/fana has not stood up for crnas against the draconian nbcrna cpc requirements.” one nonmember wrote, “not standing up for [the] membership, delving into politics, ignoring opinions of membership.” the other responses were issues related to retirement and ceus. discussion and implications the aana is the largest professional organization for the nurse anesthesia profession that provides many benefits to its members and is very influential in the profession’s growth by providing a collective voice for crnas. the aana national data shows that membership percentages within the aana have decreased over the last ten years.5 this is very concerning because membership within the aana is what helps sustain the professional organization. key findings • concern by members and nonmembers with nbcrna and new cpc requirements • florida crnas with < 10 years’ experience less likely to be members aana/fana • higher degree obtained positively influenced membership within aana/fana • non-members unaware of full scope of aana benefits • aana information gleaned most from aana journal and social media • “promotion of profession” #1 reason to join aana by members • “cost of membership” #1 reason not to join aana by non-members research & educational implications declining aana membership is an important matter requiring further exploration with a larger number of nonmembers participants. incorporating phone interviews and social media recruitment strategies as part of the methodology could increase the number of nonmembers’ responses. dissatisfaction with the new nbcrna cpc recertification requirements, cost of membership, and education were identified as membership barriers. further research into benefits of cpc recertification and its contribution to professional growth and promotion would help educate all crnas. lack of education about the aana contributes to dissatisfaction about membership and could also be leading to higher nonmember percentages. anesthesia schools provided the least amount of education regarding the aana compared to other avenues, including social media and aana journal. a recommendation to increase aana education and participation in schools is suggested. a recommendation to fana leadership is to develop some type of education module or program and work with anesthesia programs to identify a good time and way to incorporate that education early on throughout an srnas educational journey. considering srnas in the state of florida are required to be members, this would allow them to understand better where their money is going and gain an education about the aana from a reputable source. limitations a low response rate was an anticipated limitation, and several methods were developed to increase response rates (eg, recruitment email, email reminders). non-members were primarily the unresponsive cohort. the survey was intended for crnas only. however, student registered nurse anesthetists (srnas) also received the link to the survey to submit a response. the covid-19 pandemic was also an unexpected limitation. the survey was released in april, which was very early during the pandemic when there was so much uncertainty and fear circulating about the virus. one noticeable effect it had was that it slowed down communication between everyone involved with the project. however, it is almost impossible to understand how this may have truly impacted the scholarly project. the aana is crucial for crnas and professional advancement. understanding why membership percentages are declining is important. major determinants that influence membership included benefits such as ceus, political advocacy, and professional development. the significant barriers to membership identified included the cost of membership, issues surrounding nbcrna cpc requirements, and overall lack of education about the aana. texas christian university “the science behind the art” volume 10 no.2 2022 anesthesia ejournal online issn 2333-2611 page 10 references 1. farina ca, wilson w, fitzsimmons k. exploring strategies to increase and sustain membership in the american association of nurse anesthetists. aana j. 2016;84(6): 396. pmid: 28235172. 2. ki e, wang y. membership benefits matter. nonprofit manag leadersh. 2016:27(2): 199-217. doi:10.1002/nml.21230 3. ross st. factors affecting occupational therapists’ decisions to join their state association [master’s thesis]. accessed may 2020. https://scholarworks.gvsu.edu/cgi/viewcontent.cgi?article=1674&context=theses. 2009. 4. walton k. barriers to membership in a professional organization for advanced practice nurses. proquest dissertations & theses full text. accessed may 2020 https://scholarworks.waldenu.edu/cgi/viewcontent.cgi?article=5287&context=dissertations. 2017. 5. american association of nurse anesthesiology. state membership statistics. accessed may 2020. published 2018. https://www. aana.com/states/state-membership-statistics. 6. the grade working group. grade. accessed may 2020. published 2019. http://www.gradeworkinggroup.org. 7. differencebetween.com. difference between association and organization. accessed may 2020. published 2011. http://www. differencebetween.com/differencre-betwwen-association-and-vs-organization/. 8. barrier. american heritage® dictionary of the english language. 5th ed. boston, ma. houghton mifflin harcourt. accessed may 2020. published 2016. http://www.thefreedictionary.com/barrier. 9. determinate. american heritage® dictionary of the english language. 5th ed. boston, ma. houghton mifflin harcourt. accessed may 2020. published 2016. http://www.thefreedictionary.com/determinate 10. florida association of nurse anesthetists. fana home page. accessed may 2020. updated 2019. https://www.fana.org. 11. ritchie l, gilmore c. what does it mean to be a professional nurse? nurs n z. 2013;19(8):32. pmid 24279056. 12. mori c, mullen n, hill ee. describing the role of the clinical research nurse. research practitioner. 2007;8(6), 220228. 13. esmaeili m, dehghan‐nayeri n, negarandeh r. factors impacting membership and non‐membership in nursing associations: a qualitative study. nurs health sci. 2013;15(3):265-272. doi:10.1111/nhs.12012. 14. petersen e, wascher m, kier k. analysis of pharmacy student motivators and deterrents for professional organization involvement. curr pharm teach learn. 2017;9(4):543-550. doi:10.1016/j.cptl.2017.03.024. 15. wotherspoon se, mccarthy pw. the factors and motivations behind united kingdom chiropractic professional association membership: a survey of the welsh institute of chiropractic alumni. chiropr man therap. 2016;24(1):35. doi:10.1186/ s12998-016-0115. 16. kung ym, rudner lugo n. political advocacy and practice barriers: a survey of florida aprns. j am assoc nurse pract. 2015;27(3):145-51. doi:10.1002/2327-6924.12142. 17. poole j, borza j, cook la. impact of education on professional involvement for student registered nurse anesthetists’ political activism: does education play a role? aana j. 2019;87(2):138-143. pmid: 31587727. 18. gallivan h, tieman j. organisational engagement: an examination of members’ engagement in the irish dental association. j ir dent assoc. 2012 dec-2013 jan;58(6):308-15. pmid: 23420970. 19. act academy. plan, do, study, act (pdsa) cycles and the model for improvement. accessed may 2020. published 2021. https://improvement.nhs.uk/documents/2142/plan-do-study-act.pdf. texas christian university “the science behind the art” volume 10 no.2 2022 anesthesia ejournal online issn 2333-2611 page 11 http://dx.doi.org/ http://dx.doi.org/ texas christian university “the science behind the art” volume 10 no.4 2022 anesthesia ejournal online issn 2333-2611 page 5 effectiveness of total intravenous anesthesia in endoscopic sinus surgery anna busalacchi, rn, bsn, ccrn affiliation: texas christian university grant/financial support: none keywords: functional endoscopic sinus surgery, anesthesia, total intravenous anesthesia abstract a 58-year-old female presented for functional endoscopic sinus surgery (fess) to treat chronic rhinosinusitis. fess has been mainstay treatment for chronic rhinosinusitis, with or without nasal polyps. goals for fess included optimal visualization of anatomical structures with minimal bleeding in the surgical field.1 the anesthetic technique chosen, either total intravenous anesthesia (tiva) or inhalational anesthesia (ia), has shown to affect visibility of the sinonasal mucosa, dictating outcome of intraoperative blood loss. differences between anesthetic agents focused on vasodilation, particularly in the nasal mucosa.2,7,8 current evidence supported tiva as the superior anesthetic technique in fess, as it has shown to successfully reduce intraoperative blood loss with superior surgical visibility. aej volume 10no. 4 2022 about the author: anna busalacchi is a registered intensive care unit nurse, currently enrolled in texas christian university nurse anesthesia program. texas christian university “the science behind the art” volume 10 no.4 2022 anesthesia ejournal online issn 2333-2611 page 6 powerpoint template ©2009 texas christian university, center for instructional services. for educational use only. content is the property of the presenter and their resources. introduction • endoscopic sinus surgery (ess) is the mainstay treatment currently for chronic rhinosinusitis, with or without nasal polyps. • goals for successful ess: optimal visualization of anatomical structures and landmarks with minimal blood loss/bleeding in surgical field.1 • ess is generally conducted under general anesthesia for patient comfort utilizing total intravenous anesthesia (tiva) for optimal surgical field visualization, yet inhalational anesthesia (ia) is still being used in these cases.3 • the research promoting the use of tiva stems from the pharmacodynamics of propofol versus inhalational agents such as sevoflurane and isoflurane.1,3,6 • the difference between these agents are how they produce vasodilation in the body and particularly the nasal mucosa. • anesthetic technique has shown to affect visibility of the sinonasal mucosa and dictate the outcomes of blood loss and operative time. • highlighting the difference between tiva and ia shines a light on the influence that anesthesia can have on these patients’ surgical course. discussion case key points: • tiva requested by surgeon as anesthetic technique • very minimal blood loss • no hemodynamic abnormalities throughout entire case case critiques: • emergence was delayed by ten minutes, due to propofol lingering; propofol infusion should have been turned off sooner • estimated blood loss was calculated by amount in suction canister with amount of irrigation subtracted; many researchers are now recommending looking at hemoglobin values before and after the case clinical rationale: • surgeon must be able to identify anatomic landmarks within confined surgical space to complete ess. • by decreasing arterial blood supply to the ethmoid bed, propofol leads to better visibility for the surgeon and better patient outcomes.2 • those with more severe chronic rhinosinusitis have shown to benefit even greater with tiva in surgical outcomes.7 the effectiveness of total intravenous anesthesia in endoscopic sinus surgery anna busalacchi, bsn, rn, texas christian university case description pre-anesthestic evaluation: • a 58-year-old female, 67 inches, 107.4 kilograms, asa ii presented for endoscopic sinus surgery (ess) to treat chronic rhinosinusitis • medical history: sinusitis, hyperlipidemia, obesity • preoperative vital signs: hr 80, bp 151/89 mmhg, rr 16, spo2 97% • preoperative medications: clindamycin 900 mg iv, midazolam 2 mg iv, both given in the preoperative area intraoperative management: • general anesthesia induced with lidocaine 60 mg iv, propofol 180 mg iv, and succinylcholine 120 mg iv • following induction: rocuronium 40 mg iv, dexamethasone 10 mg iv, propofol infusion started at 100 mcg/kg/min • maintenance: propofol infusion remained on throughout procedure, rocuronium 10 mg given one hour into case • at time of closure: propofol infusion turned off, ondansetron 4 mg iv, ketorolac 30 mg iv, acetaminophen 1 g iv • no vital sign abnormalities throughout case noted • estimated blood loss of case: 50 ml, calculated by amount in canister with irrigation subtracted postoperative course: • reversed with sugammadex 200 mg iv, extubated and transferred to pacu with oral airway in place and dressing under nose placed and secured by surgeon • pacu vital signs: hr 74, bp 133/70 mmhg, rr 18, spo2 95% follow up: • patient dressing under nose observed with no bloody drainage, discharged to home within 2 hours of procedure ending • no nausea or pain noted by patient before discharge references 1. lu vm, phan k, oh lj. total intravenous versus inhalational anesthesia in endoscopic sinus surgery: a meta-analysis. laryngoscope. 2020;130(3):575-583. 2. deconde as, thompson cf, wu ec, suh jd. systematic review and meta-analysis of total intravenous anesthesia and endoscopic sinus surgery. int forum allergy rhinol. 2013;3(10):848-854. 3. gomez-rivera f, cattano d, ramaswamy u, et al. pilot study comparing total intravenous anesthesia to inhalational anesthesia in endoscopic sinus surgery: novel approach of blood flow quantification. ann otol rhinol laryngol. 2012;121(11):725-732. 4. chaaban mr, baroody fm, gottlieb o, naclerio rm. blood loss during endoscopic sinus surgery with propofol or sevoflurane. jama otolaryngol head neck surg. 2013;139(5):510. 5. ahn hj, chung s-k, dhong h-j, et al. comparison of surgical conditions during propofol or sevoflurane anaesthesia for endoscopic sinus surgery. br j anaesth. 2008;100(1):50-54. 6. eberhart lh, folz bj, wulf h, geldner g. intravenous anesthesia provides optimal surgical conditions during microscopic and endoscopic sinus surgery. laryngoscope. 2003;113(8):1369-1373. 7. brunner jp, levy jm, ada ml, et al. total intravenous anesthesia improves intraoperative visualization during surgery for high-grade chronic rhinosinusitis: a double-blind randomized controlled trial. int forum allergy rhinol. 2018;8(10):1114-1122. 8. kolia nr, man l-x. total intravenous anaesthesia versus inhaled anaesthesia for endoscopic sinus surgery: a meta-analysis of randomized controlled trials. rhinology. 2019;57(6):402-410. 9. baban mi, mirza b, castelnuovo p. radiological and endoscopic findings in patients undergoing revision endoscopic sinus surgery. surg. radiol. anat. 2020;42(9):1003-1012. conclusion • the nasal mucosa is a highly vascularized area. when operated on, bleeding can lead to a great deal of blood loss and challenging visibility for the surgeon.1 • the use of tiva over ia has proven to lead to decreased blood loss and a cleared surgical field, graded using the wormald visibility scale in a large pool of randomized controlled trials and prospective studies.1 • tiva versus ia has also proven to have no major difference in the hemodynamic profile of these researched patients in the noted studies, proving its safety.1 figure 1: comparison of tiva verses “balanced anesthesia,” meaning the use of inhalational agents, via a visual analog scale used by surgeons to grade the surgical field visibility.6 figure 2: radiological and endoscopic images demonstrating the progression of increased bleeding and decreased surgical visibility in a revision ess.9 propofol vasodilation mechanism: concentration-dependent vasodilatory effect7 depresses central sympathetic tone3,7 avoids peripheral vasodilation1 depresses cerebral blood flow= decreased arterial supply to the ethmoid bed2 inhalational agent vasodilation mechanism: concentration-dependent vasodilatory effect7 directly acts on smooth muscle of blood vessels7,8 leads to vasodilation of peripheral and cerebral blood vessels7,8 relaxes pre-capillary sphincters in the mucosa= increases blood flow to the paranasal sinuses7,8 key findings from literature • tiva has proven to be the superior anesthetic technique because it has shown to successfully reduce intraoperative blood loss with superior surgical visibility.7 • propofol, with the use of a short-acting opioid, such as remifentanil, is currently the leading anesthetic technique in ess.6 • gaps in research have become evident including the need for standardized surgical visibility scoring, how more extensive chronic rhinosinusitis affects surgical outcomes regardless of anesthetic technique, and the quality of life of these patients following their surgery and anesthesia.2,5,6 literature review • the overwhelmingly present theme across many studies supporting tiva highlight the benefits of using propofol as the main anesthetic drug and how it interacts in the body.1,2,3,7 • many studies used conducted research in similar manners of blindly assigning patients to receive tiva or ia and measuring outcomes of blood loss and surgical visibility. • patients with varying degrees of chronic rhinosinusitis were studied. • hemodynamic profiles were monitored and compared between anesthetic techniques.1,4 texas christian university “the science behind the art” volume 10 no.3 2022 anesthesia ejournal online issn 2333-2611 page 7 transesophageal echocardiography use for orthotopic liver transplant colton sedberry, bsn, rn affiliation: texas christian university grant/financial support: none keywords: transesophageal echocardiography, liver graft, liver transplantation abstract transesophageal echocardiography (tee) is an invaluable tool used in cardiac surgery. so why is it not consistently used in other high-risk surgeries, such as orthotopic liver transplantation (olt)? hemorrhage, acute cardiac dysfunction, fluid shifts, and other intraoperative pathologies associated with olt present many challenges for the anesthesia provider. therefore, timely identification, evaluation, and intervention of intraoperative pathology are necessary to maintain hemodynamic stability. traditionally, intra-arterial and pulmonary artery catheters (pacs) were used as hemodynamic monitors. recently, however, transesophageal echocardiography (tee) has been used for noncardiac surgery to assess hemodynamic status. this poster discusses perioperative care and current literature surrounding tee and olt using a case study approach. patients undergoing olt with both tee and pac had the lowest hospital length of stay (los), 30-day mortality, and infusion of fluids. this suggests that the addition of tee with traditional monitors may be the safest method of hemodynamic monitoring. aej volume 10no. 3 2022 about the author: colton sedberry is a registered nurse pursuing his dnp in nurse anesthesia at texas christian university in fort worth, texas. texas christian university “the science behind the art” volume 10 no.3 2022 anesthesia ejournal online issn 2333-2611 page 8 p o w e rp o in t t e m p la te © 2 0 0 9 t e x a s c h r is t ia n u n iv e rs it y , c e n te r fo r in s t ru c t io n a l s e rv ic e s . f o r e d u c a t io n a l u s e o n ly . c o n te n t is th e p ro p e r ty o f th e p re s e n te r a n d th e ir r e s o u rc e s . introduction/background • this scholarly project focuses on a high-risk patient undergoing an orthotopic liver transplant (olt). • hemorrhage, acute cardiac dysfunction, fluid shifts, and other intraoperative pathologies associated with olt present many challenges for the anesthesia provider.1 • each stage of olt presents different challenges and varying hemodynamic shifts. (figure 1).1 • timely identification, evaluation, and intervention of intraoperative pathology are necessary to maintain hemodynamic stability. • traditionally, intra-arterial and pulmonary artery catheters (pacs) were used as hemodynamic monitors.2 • tee utilization as a hemodynamic monitor is becoming more popular in olt, either exclusively or in addition to pac.2,7 • the consideration that the use of tee may have improved this patient’s intraoperative management was the inspiration for this scholarly project. purpose • the first objective of this project is to identify what benefits are gained from the use of tee in addition to traditional hemodynamic monitoring techniques (cvp/paop) during olt. • the second objective is to determine how these findings affect fluid and medication administration in the hemodynamically unstable patient. discussion • the literature review found evidence that intraoperative tee use for olt was proficient at rapidly identifying multiple pathologies and guiding fluid and vasoactive agent administration. • however, there was not a high quality of evidence supporting new tee findings with better patient outcomes. both srs were unable to perform a metanalysis because of limited analytical data and variance in study methodology.3,5 • additionally, sample sizes for the 3 reviewed observational cohort studies were relatively small.2,4,6 • the subjective nature of the anesthesia provider’s interpretation of data and decision to implement a treatment was a common limitation found in the reviewed literature. • anesthesia providers’ level of experience or certification with tee was also variable throughout the studies. however, this may reflect a realistic view of clinical practice. • the best outcome-based evidence retrieved suggests that tee combined with pac produces optimal patient outcomes.2 the authors found that the patients undergoing olt with both tee and pac had the lowest hospital los, 30-day mortality, and infusion of fluids.2 this suggests that the addition of tee with traditional monitors may be the safest method of hemodynamic monitoring. transesophageal echocardiography use for orthotopic liver transplantation colton sedberry, bsn, rn, texas christian university case summary pre-anesthetic evaluation • a 50-year-old caucasian female underwent general endotracheal anesthesia for an olt. • medical history: cirrhosis, refractory ascites, portal hypertension, portal vein thrombosis, hepatitis c, thrombocytopenia, anemia, obesity, and coronary artery disease. • surgical history: splenic embolization, coronary artery bypass graft, and cesarean section. • current medication: furosemide 100 mg daily, spironolactone 300 mg daily, lactulose 30 mg four times daily, midodrine 5 mg twice a day, rifaximin 550 mg twice a day, montelukast 10 mg daily, gabapentin 600 mg three times a day, trazodone 50 mg daily, vitamin b12 500 mcg daily, and ferrous sulfate 60 mg daily. • assessment: abdominal distention, tenderness, jaundice, and +1 edema to bilateral lower extremities. intraoperative course • preoperative vs: bp 148/75, hr 89, spo2 92%, rr 24 • iv induction: 100 mg lidocaine, 100 mg propofol, 5 mcg sufentanil, 50 mg rocuronium. • direct laryngoscopy with miller #2 blade for introduction of 7.0 endotracheal tube (ett). • ventilation mode: simv/ps • maintenance: sevoflurane and vecuronium • hemodynamic monitors: arterial line and introducer with pa catheter. • initial hemodynamic values: cvp 22, pa pressure 33/21, ci 2.4 • hemodynamic infusions: epinephrine and norepinephrine. • total fluids and blood products: 1.5 l of 5% albumin, 6 units prbcs, 5 units ffp, and 1 unit of platelets. • rapid transfusion and warming device was used for fluid and blood product administration. • profound hypotension occurred at various points throughout the case, at times with unknown etiology. the greatest period of hemodynamic instability was during the post-anhepatic stage (donor liver reperfusion). postoperative course • patient remained intubated and transferred to cvicu. • 48 hours postoperatively, patient remained intubated and required a furosemide infusion and dialysis to treat acute kidney injury. references 1. blasi a, biancofiore g, green d. haemodynamic monitoring during liver transplant surgery. in: milan z, goonasekera c, eds. anesthesia for hepatico-pancreatic-biliary surgery and transplantation. springer; 2021:195-208. 2. zerillo j, hill b, kim s, demaria s, mandell ms. use, training, and opinions about effectiveness of transesophageal echocardiography in adult liver transplantation among anesthesiologists in the united states. semin. cardiothorac. vasc. anesth. 2018;22:137-145. doi: 10.1177/1089253217750754 3. de marchi l, wang cj, skubas nj, et al. safety and benefit of transesophageal echocardiography in liver transplant surgery: a position paper from the society for the advancement of transplant anesthesia (sata). liver transplant. 2020;26:1019-1029. doi: 10.1002/lt.25800 4. fayad a, shillcutt s, meineri m, ruddy td, ansari mt. comparative effectiveness and harms of intraoperative transesophageal echocardiography in noncardiac surgery: a systematic review. semin cardiothorac vasc anesth. 2018;22:122-136. doi: 10.1177/1089253218756756 5. hofer ck, zollinger a, rak m, et al. therapeutic impact of intra-operative transoesophageal echocardiography during noncardiac surgery. anaesthesia. 2004;59:3-9. https://doiorg.ezproxy.tcu.edu/10.1111/j.1365-2044.2004.03459.x. 6. hofer re, vogt mnp, taner t, findlay jy. influence of intraoperative transesophageal echocardiography and pulmonary artery catheter monitoring on outcomes in liver transplantation. transplant. direct. 2020;6:e525-e525. doi: 10.1097/txd.0000000000000972 7. shillcutt, sasha k., md, fase, ringenberg kj, md, chacon mm, md, et al. liver transplantation: intraoperative transesophageal echocardiography findings and relationship to major postoperative adverse cardiac events. j. cardiothorac. vasc. anesth. 2016;30:107-114. https://doiorg.ezproxy.tcu.edu/10.1053/j.jvca.2015.09.009. supporting evidence tee as a hemodynamic monitor • one systematic review (sr) qualitatively assessed 39 articles that included 3,193 participants addressing new diagnoses.3 table 1 details the main diagnoses from each.3 • one prospective database analysis including 99 participants undergoing noncardiac surgery (7 undergoing olt) observed 165 new findings with the additional use of tee to pac monitoring.6 • a retrospective cohort study included 100 participants undergoing tee assessment for olt; 88% of patients had at least 1 abnormal intraoperative tee finding during olt.4 the most common finding included microemboli (44%), right ventricular dysfunction (31%), and thromboemboli (27%).4 tee was also found to accurately distinguish hemodynamic instability caused by rv dysfunction and hypovolemia.4 influence of tee on fluid and medication administration • one sr included 7 noncomparative studies involving a change in management attributed to tee use. change in management ranged from 17 to 81%.5 • one prospective database analysis including 99 participants undergoing noncardiac surgery performed a subgroup analysis of 17 liver and lung transplant patients.6 tee-guided interventions occurred as follows6 (p < 0.05): ø vasodilator therapy in 63% of patients ø vasopressor therapy in 56% of patients ø fluid management in 50% of patients • one observational cohort study including 318 participants compared tee, pac, and tee+pac.2 the tee+pac group had the shortest median hospital length of stay (los) and had the lowest 30-day mortality rate.2 tee+pac group received the lowest volume of crystalloid and the lowest perioperative infusions.2 the tee group had the least perioperative time with map < 60 mmhg.2 conclusions and recommendations for practice • tee can be used to promptly identify pathology associated with hemodynamic instability and provide information on valvular morphology and cardiac function. • while the research displays an influence of tee findings on fluid, vasopressor, and vasodilator usage during olt, more research needs to be taken to verify the positive impact of this influence. • until beneficial outcomes have been validated, the use of tee cannot be recommended as a comprehensive intervention for every olt. • tee should be used based on the anesthesia provider’s judgment along with other monitoring tools. recommendation for future research • higher-quality research should be performed to validate the outcome-based benefits of tee findings and subsequent intraoperative interventions. • future research with more rigorous study designs that include greater control and randomization should be performed. • data acquisition via creation of large database analyses would control for confounding factors and selection bias.5 figure 1. hemodynamic changes during various stages of olt1 references 1. dalia aa, flores a, chitilian h, fitzsimons mg. a comprehensive review of transesophageal echocardiography during orthotopic liver transplantation. j cardiothorac vasc anesth. 2018;32:1815-1824. https://doi.org/10.1053/j.jvca.2018.02.033. 2. hofer re, vogt mnp, taner t, findlay jy. influence of intraoperative transesophageal echocardiography and pulmonary artery catheter monitoring on outcomes in liver transplantation. transplant direct. 2020;6:e525-e525. doi: 10.1097/txd.0000000000000972 3. de marchi l, wang cj, skubas nj, et al. safety and benefit of transesophageal echocardiography in liver transplant surgery: a position paper from the society for the advancement of transplant anesthesia (sata). liver transplant. 2020;26:1019-1029. doi: 10.1002/lt.25800 4. shillcutt, sasha k, ringenberg kj, chacon mm, et al. liver transplantation: intraoperative transesophageal echocardiography findings and relationship to major postoperative adverse cardiac events. j cardiothorac vasc anesth. 2016;30:107-114. https://doiorg.ezproxy.tcu.edu/10.1053/j.jvca.2015.09.009. 5. fayad a, shillcutt s, meineri m, ruddy td, ansari mt. comparative effectiveness and harms of intraoperative transesophageal echocardiography in noncardiac surgery: a systematic review. semin cardiothorac vasc anesth. 2018;22:122-136.doi: 10.1177/1089253218756756 6. hofer ck, zollinger a, rak m, et al. therapeutic impact of intra-operative transoesophageal echocardiography during noncardiac surgery. anaesthesia. 2004;59:3-9. https://doiorg.ezproxy.tcu.edu/10.1111/j.1365-2044.2004.03459.x. 7. zerillo j, hill b, kim s, demaria s, mandell ms. use, training, and opinions about effectiveness of transesophageal echocardiography in adult liver transplantation among anesthesiologists in the united states. semin cardiothorac vasc anesth. 2018;22:137-145.doi: 10.1177/1089253217750754 8. patrick j. lynch. transesophageal echocardiography ultrasound diagram. wikimedia commons. december 23, 2006. accessed march 8, 2022. https://commons.wikimedia.org/wiki/file:transesophageal_echocardiography_diagram.svg table 1. new diagnoses made from tee assessments in olt3 figure 3. positioning of tee probe in relation to heart.8 figure 2. tee image displaying dilated and dysfunctional right ventricle1 