








































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 hyper- and 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. 



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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 self-
management. 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)



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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 



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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 post- anesthesia 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. 



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 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 Recom-

mendation (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 hypo- and 
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/



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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 post-

anesthesia 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 two-
thirds 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
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