208 J Contemp Med Sci | Vol. 6, No. 5, September-October 2020: 208–212 Original ISSN 2413-0516 Introduction Patients admitted to the hospital are exposed to various inva- sive procedures during their hospitalization, so one of the biggest challenges in nursing is ensuring patient comfort and pain relief, and this has been always acknowledged in the activities and policies of the health-care system.1 One of the most common invasive procedures in hospitalized patients is direct perforation of the vein to collect blood samples for diagnostic or therapeutic purposes,2 so that almost all hos- pitalized patients at least once during their hospital stay and approximately one-quarter of them have been exposed to this procedure more than three times.3 This can cause pain and suf- fering for the patient, which can be a challenge for care and is still a common problem associated with blood sampling in clinical settings.4 Studies have shown high levels of acute pain, anxiety, stress, and irritability in patients of different ages fol- lowing repeated vein punctures in one day to collect blood samples.5, 6 In addition, the chance of vascular injury, bleeding, and nosocomial infection increases and makes future vascular use difficult7, 8 and in rare cases causes peripheral nerve dam- age.9 It puts nurses at risk of unintended needle entry (needle stick).10 In some patients, such as those with chronic diseases, patients who have had multiple intravenous (IV) injections, IV drug abusers, patients with skin problems at the venous lines, patients taking anticoagulants, the elderly patients with fragile veins, and children, finding a suitable vein may require multi- ple vein punctures.11, 12IV catheters are commonly used in most hospitalized patients for medical purposes such as injections of fluids, medications, and blood.11, 14 These catheters make it unnecessary to use a needle and make it easier for patients with difficult venous blood sampling.13 This protects patients from repeated injuries by venous puncture sampling and nurses from needle puncture, providing comfort and time saving for patients and nurses, especially those in intensive and acute care, and suffer from collapsed veins, speeding up the results of tests and increasing the speed of medical and nursing care, reducing the risk of infections and other complications of blood sam- pling.11 Sampling for diagnostic tests using arterial and venous catheters has been controversial since half a century ago.15 The results of some studies have shown that by inserting and main- taining an IV catheter and accessing the patient’s bloodstream, the blood sample needed for diagnostic tests can be obtained to reduce the complications of direct blood sampling.4, 5, 10 On the other hand, some studies have concluded that laboratory values obtained from IV catheter blood samples are invalid and recommend further studies in this area.5, 7, 13 On the other hand, the results of some studies suggest that the infusion intake through the IV catheter may affect the results of tests performed on IV catheter blood samples.7, 15. The present study aimed to compare the results of sodium, potassium, creatinine, and urea nitrogen levels in venous blood samples taken by direct blood sampling and peripheral venous catheter. Materials and Methods This analytical cross-sectional study was performed in 1396 (2017) from Poor-Sina Medical Center in Rasht. Sample size had 95% confidence interval and 90% test power according to The biochemical parameters in venous blood sampling by direct venipuncture and peripheral intravenous catheter Fatemeh Jaafaraghaei1, Monireh Aghajany-Nasab2*, Mahsa Aghaei1, Nazila Javadi pashaki3, Ehsan Kazemnejhad Leili1 1 Nursing and Midwifery Faculty, Guilan University of Medical Sciences, Rasht, Iran 2 Department of Biochemistry, Molecule and Cell Research Center, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran 3 Social Determinants of Health Research Center, Nursing and Midwifery Faculty, Guilan University of Medical Sciences, Rasht, Iran Corresponding author: Aghajany-Nasab Monireh, (E-mail: maghajany@gums.ac.ir ) (Submitted: 14 July 2020 – Revised version received: 21 July 2020 – Accepted: 08 August 2020 – Published online: 30 October 2020) Abstract Objectives: The aim of this study was to compare the results of some biochemical values in venous blood samples obtained by direct venipuncture (DV) and peripheral venous catheter (PVC). Methods: In this cross-sectional study, 78 hospitalized patients from different wards of Poor-Sina Medical and Educational Center of Rasht in 2017 were divided into 3 equal groups, including patients who were treated with normal saline and dextrose saline and those who did not receive this solution. Two separate blood samples were obtained from each patient, one from PVC and the other from DV. The levels of sodium, potassium, creatinine and blood urea nitrogen (BUN) were measured and compared. Results: Difference of PVC with DV in BUN was generally 0.32±3.18 mg/dl; creatinine, sodium, and potassium were 0.02±0.12 mg/dl, 1.00±2.49 mEq/L and 0.15±0.48 mEq/L respectively. There were no statistically significant differences between the two methods in relation to BUN and creatinine (P = 0.377 and P = 0.149, respectively), but significant differences in levels of sodium and potassium were observed between the two blood sampling methods (P = 0.001 and P = 0.008, respectively). Conclusion: According to the results of this study and other studies, PVC can be used to measure BUN and creatinine, not so for sodium and potassium. For other parameters, further investigation is needed. Keywords: Biochemical values, Peripheral catheterization, Blood specimen collection 209 Original The biochemical parameters in venous blood sampling by direct venipunctureFatemeh Jaafaraghaei J Contemp Med Sci | Vol. 6, No. 5, September-October 2020: 208–212 the following sampling formula and based on similar studies 26 individuals were included in each group.16 n Z Z SD d = − + −       ( )2 1 2 1 2 2 2 � � �� α β Inclusion criteria included patients over 18 years of age with complete consciousness, with no coagulation problems, available peripheral veins, and peripheral venous with gauge- 20 catheter for up to 72 hours (receiving normal saline or dextrose saline or no infusion), who were prescribed by a physician who required blood sampling to check for blood sodium, potassium, creatinine, and urea nitrogen levels. Exclusion criteria included: patients with anemia and those with an IV arterial fistula and patients who had inoperable peripheral catheter or prolonged blood sampling more than 20 seconds for any reason and hemolyzed blood samples and actually. Patients were divided into three groups (26 in each) based on the type of infusion that they received; Group 1: normal saline, Group 2: dextrose saline, and Group 3 did not receive any infusion and the catheter was heparin-locked. Two separate blood samples were collected from each patient by one nurse, first sample from a peripheral vein catheter and the other from opposite hand direct vein blood sampling.16 In the first and second groups, serum therapy was stopped for 15 seconds.5 Then, in all three groups before blood sampling, the standard tourniquet was closed for 30 seconds, 5 cm above the peripheral venous catheter site.11, 15 The volume of the catheter’s dead space according to the size was set to 0.1 cc, and to ensure that, approximately 0.5 cc of blood (2.5 times and more) was removed and discarded13 and by another syringe, 3 ml was obtained for the test by the same route. Immediately after catheter blood sampling in all three groups, another 3 cc blood samples were obtained from the opposite arm via direct blood sampling. After the sampling was com- pleted, the IV fluid flow resumed as before. The test tubes were designated a code by researcher. The laboratory staff and sta- tistical analyst were unaware of the coding and study groups. Samples were sent to one laboratory simultaneously to avoid possible variation between laboratories. Measurement of blood urea nitrogen (BUN) performed by using a diagnostic urea Bionic kit (Photometric - urea and alpha ketoglutarate dehydrogenase method - at a wavelength of 340 nm) and creatinine was measured by Jaffe’s method. Creatinine forms an amber yellow complex with alkaline picrate which was measured photometrically (Pars Azmoon Co., Tehran, Iran). Sodium and potassium were determined by ion selective elec- trodes. A database sheet was prepared which included the demographic information including age, gender, underlying diseases including diabetes, hypertension, and dyslipidemia, catheter fluid infusion rate, and type of received infusion, along with the results of laboratory tests. Data Analysis The data were analyzed using SPSS v18 software. Quantitative variables were expressed as mean ± standard deviation and qualitative variables were expressed as frequency and percent- age. Paired t-test was used to evaluate the differences between the two blood sampling methods and ANOVA or chi-square test was used to assess the differences between the three groups. P <0.05 was considered significant. Ethical Considerations The present study was conducted under the auspices of the Research Ethics Committee of Guilan University of Medical Sciences (Approved Code: IR.GUMS.REC.1395 / 240) and the researchers adhered to all the principles of protocols and guide- lines recommended by the Helsinki Convention on Ethics in Research. Prior to entering the study, informed consent was obtained from all participants. Study participants were assured that all patient information would be kept confidential and the outcome of the design would be generally published without mentioning the patient’s name and any specifications. Patient participation in this study was completely voluntarily and no changes were made in the treatment or care of their patients due to their participation or not. Results In general, the youngest patient was 21 years old and the old- est was 90, with a mean age of 51.28 years. Analysis of the results among the three groups showed that there was no sta- tistically significant difference in age between the three groups (P=0.689). Frequency of male gender was 61.5% (n=16) in normal saline group, 65.4% (n=17) in dextrose saline group, and 17 cases (65.4%) in non-serum receiving group (P=0.946). Based on the history of underlying disease, it was found that overall 10 patients (12.8%) with diabetes, 20 patients (26.6%) with hypertension, and 10 patients (12.8%) with dyslipidemia were included in this study. Although the frequency of diabet- ics was higher in the normal saline group (P=0.014), there was no statistically significant difference between the groups about the hypertension and dyslipidemia (P=0.625). There was no statistically differences between groups with respect to periph- eral infusion rate (P=0.22) (Table 1). Discussion The aim of the present study was to compare the results of sodium, potassium, creatinine, and urea nitrogen levels in venous blood samples obtained by direct blood sampling and peripheral venous catheter pathway, which were performed in order to achieve the primary and basic goals and to improve the quality of nursing care. The main aim is the reduction of pain and complications of direct blood sampling which patients may encounter during hospitalization. The results of the present study showed that there was no statistically significant difference between the two methods of measuring BUN and serum creatinine between the study groups. According to the study of Hambleton et al in 201410 and Zlotowski et al in 200117 aiming comparison of labora- tory tests through two methods of direct blood sampling and peripheral catheter and changes in laboratory results following IV normal saline injection indicated that the blood sampling method had no relationship with BUN and serum creatinine levels. Also, the results of BUN and serum creatinine follow- ing the two methods of blood sampling in patients receiving dextrose saline in the study of Ortels et al in 20143 were not significantly different. In addition, the results of Yazdankhah Fard et al.’s study in 201411 showed that there is no significant 210 Original The biochemical parameters in venous blood sampling by direct venipuncture Fatemeh Jaafaraghaei J Contemp Med Sci | Vol. 6, No. 5, September-October 2020: 208–212 Table 1. Background variables among different study groups. P valueTotalNL GroupDS GroupNS Group Age 52/31±20/52#52/88±18/7748/65±17/9351/28±18/950/689*Age Sex 0/946# (%61/5)16(%65/4)17(%65/4)17(%64/1)50Male (%38/5)10(%34/6)9(%34/6)9(%35/9)28Female Diabetes Hx 0/014# (%26/9)7(%0)0(%11/5)3(%12/8)10Yes (%73/1)19(%100)26(%×8/5)23(%87/2)68No HTN Hx 0/625# (%,30/8)8(%26/9)7(%19/2)5(%25/6)20Yes (%69/2)18(%73/1)19(%80/8)21(%74/4)58No DLP Hx 0/892# (%11/5)3(%11/5)3(%15/4)4(%12/8)10Yes (%88/5)23(%88/5)23(%84/6)22(%87/2)68No Venous Infusion Rate 0/217# (%,34/6)9(%53/9)14-(%44/2)2310 gtt/min (%42/3)11(%19/2)5-(%30/8)1615 gtt/min (%3/9)1(%11/5)3-(%7/7)420 gtt/min (%19/2)5(%15/4)4-(%17/3)9)25 gtt/min * ANOVA Test. # Chi-Square Test. NS: Normal Saline Group, DS: Dextrose Saline Group, NL: No Infusion Group. Table 2. Biochemical results using direct and peripheral catheter sampling in groups. Variables Groups Direct Sampling Catheter Sampling Sampling Methods Difference Significance Level* BUN (mg/dl) NS 17/31±7/81 16/81±11/12 -0/50±5/00 0/614 DS 15/15±7/72 14/58±7/20 -0/58±1/50 0/061 NI 14/35±4/38 14/46±3/93 0/12±1/93 0/762 Cr (mg/dl) NS 1/10±0/59 1/07±0/61 -0/03±0/14 0/337 DS 1/05±0/36 1/02±0/28 -0/03±0/12 0/153 NI 1/02±0/17 1/02±0/22 0/00±0/11 0/999 Na (mEq/L) NS 136/19±2/06 137/81±2/42 1/62±2/47 0/003* DS 135/54±2/56 136/50±3/19 0/96±2/86 0/099 NI 136/96±2/46 137/38±2/82 0/42±2/02 0/297 K (mEq/L) NS 3/89±0/33 3/96±0/44 0/07±0/40 0/386 DS 3/73±0/52 3/82±0/42 0/08±0/39 0/279 NI 4/00±0/37 4/29±0/63 0/29±0/59 0/020* * Paired-T Test, Significant level P