Bolus Injection Versus Infusion of Furosemide in Kidney Transplantation: A Randomized Clinical Trial Afshar Zomorrodi1, Hassan Mohammadipoor Anvari 2*, Farzad Kakaei3, Farzin Solymanzadeh1, Esmaeil Khanlari1, Amin Bagheri1 Purpose: Furosemide is commonly administered to increase the urinary output in patients with transplanted kid- neys. This study compared the two administration routes of furosemide (bolus versus infusion) in kidney trans- planted patients. Materials and Methods: Fifty patients who had undergone kidney transplantation in 2015 in a hospital in Tabriz, Iran, were included in this clinical trial. They were divided into two groups: bolus (120 mg stat) and infusion (4 mg/ minute) groups. The primary outcome was urine onset time. Secondary outcomes were urine output volume, vital signs (blood pressure, heart rate), and electrolyte level (creatinine, blood urea nitrogen, sodium and potassium). After arterial and venous anastomoses, arterial clamp removal time and diuresis onset were recorded. Finally, the urinary output volumes of both groups were measured with regular urine bags for an hour after anastomosis. Then it was repeated each three hours for 24 hours, and eventually two and three days thereafter. Finally, all data were statistically analyzed. Results: Around 72% of the patients were men (mean age of 37.15 ± 14.67 years). Urine output was higher in bolus group but it was not statistically significant. Diuresis duration was measured after arterial declamping and its averages were 5.41 ± 3.7 minutes and 9.36 ± 7.65 minutes in bolus and infusion groups, respectively (P = .040). Furosemide bolus injection and infusion had no significant effect on creatinine, blood urea nitrogen, sodium and potassium. Conclusion: Furosemide bolus injection can reduce diuresis onset time compared to furosemide infusion. Keywords: clinical trial; furosemide; infusion; kidney transplantation; loop diuretic. INTRODUCTION Kidney transplantation is the last stage of kidney failure treatment with a more favorable lifestyle results and a reduction in mortality rate. The main drawback of kidney transplantation is its rejection. Here, the acute transplantation rejection is the most important predictor. The transplanted kidney will have a good long-term prognosis if it has a proper function from the beginning.(1-3) An important and fundamental issue regarding this pro- cedure is the diuresis initiation. Currently, high dosages of diuretics are being used for speeding up the diuresis initiation. The longer it takes to initiate diuresis, further complications, such as fluid retention, pulmonary ede- ma, and even acute kidney failure might occur.(3) Administration of mannitol is a commonly used meth- od to precipitate diuresis initiation. Mannitol is a major protective osmotic agent in kidney preservation.(4) Suf- ficient hydration during kidney transplantation is very important and the kidney requires sufficient perfusion for its maximum function. There is a relationship be- tween kidney transplantation and acute tubular necrosis occurrence.(3) Thus, the strategy for preventing acute tu- bular necrosis includes limiting the extent and duration of kidney ischemia and establishing and preserving the abundant intravascular volume to reduce the incidence of acute tubular necrosis.(5) Overhydration and diuretics, such as furosemide, have positive effects on reducing kidney transplant rejection. Diuresis initiation time is important for transplanted kidney’s survival. A transplanted kidney with a good function from the beginning has a good long-term prog- nosis. Thus, this study has compared the effect of bolus injection versus infusion of furosemide on diuresis ini- tiation time of patients who had received kidney trans- plantation. MATERIALS AND METHODS Written informed consent was obtained from them be- fore their participation in the study. The inclusion cri- teria were: 1) having an end-stage kidney disease and being a kidney transplant candidate; 2) having blood pressure more than 100/60 mmHg at the start of sur- gery; and 3) not having a systematic disease (except for end-stage kidney disease). The exclusion criteria were: 1) being older than 65 years; 2) having metastatic tu- 1Department of Urology, Emam Reza Hospital, Tabriz University of Medical Sciences, Tabriz, Iran. 2Department of Anesthesiology, Emam Reza Hospital, Tabriz University of Medical Sciences, Tabriz, Iran. 3Department of Surgery, Emam Reza Hospital, Tabriz University of Medical Sciences, Tabriz, Iran. *Correspondence: Mahan Building, Twenty-meter third Eastern, Paradise Alley, Street Elgoli, Tabriz, Iran. Postal Code: 5167935731. Tel: +98 41 34 78 2216. Fax: +98 41 33 35 2073. Mobile: +98 918 811 2210. Email: hmohammadipour@yahoo.com. Received December 2016 & Accepted January 2017 KIDNEY TRANSPLANTATION Vol 14 No 02 March-April 2017 3013 mors; 3) having sever homeostatic alterations during transplantation (blood pressure less than 80/50 mmHg for more than half an hour); 4) presence of chronic he- patic disease; 5) urinary tract infections; 6) urinary tract anomalies; and 7) aortoiliac diseases. Study design The participants were divided into two groups, i.e. bolus and infusion groups, using the simple randomi- zation, according to the codes assigned to each group by Minitab software. Then, the codes were categorized and the patients were divided accordingly. In the bolus group, 120 mg of bolus furosemide was administered within one minute immediately before arterial declamp- ing. In the infusion group, the infusion dosage began with 4 mg/min thirty minutes before declamping and continued afterwards. All participants received dialysis 24 hours before sur- gery. Biochemical tests for sodium, potassium, urea, and creatinine were performed. Personal characteristics, including age, sex, and body weight, were recorded. All open nephrectomy procedures were done on living do- nors by the same expert surgeon and all transplant re- cipients were operated by the same surgery team. In all cases, kidney veins were anastomosed to external iliac veins and arteries were anastomosed to the internal iliac arteries. Throughout the procedure, systolic blood pressure was preserved in the range of 120-140 mmHg. Central ve- nous pressures were maintained within 10-12 and 14-16 cmH2O before and after arterial clamping, respectively. Blood transfusion was done as needed based on hemo- globin and hematocrit levels. Following arterial and ve- nous anastomoses, the arterial clamp removal time and diuresis onset were recorded. Finally, urinary output volumes were measured for an hour after anastomosis. Then it was repeated each three hours for 24 hours, and eventually two and three days thereafter. In addition, the levels of sodium, potassium, blood urea nitrogen, and creatinine were recorded preoperatively and then daily for four days after the surgery. Outcome assessment The primary outcome was urine onset time. Therefore, when the arterial blood declamping was established, the patient's urine was measured in minutes. Secondary outcomes included volume of urine output, vital signs (blood pressure, heart rate), and electrolyte level (cre- atinine, blood urea nitrogen, sodium and potassium). Statistical analysis Statistical differences were presented as mean ± stand- ard deviation. Data analysis was done using statistical package for the social sciences (SPSS) software version 16.0 (Chicago, IL, USA). Numerical variables were compared by independent samples t-test. Categorical variables were compared by chi square or Fisher’s exact tests as appropriate. RESULTS A number of 50 patients who received kidney trans- plantation participated in this clinical trial (25 partici- pants in each group, Figure 1). Their mean ages were 32.96 ± 1.48 and 40.2 ± 10.68 years old in bolus and infusion groups, respectively (P = .084). The surgery duration was 4.16 hours in bolus group and 4.19 hours Table 1. Patients' demographic information. Bolus group Infusion group Variables Frequency % Frequency % P value Age (years old) < 20 8 32 1 4 .076 21-30 3 12 3 12 31-40 7 28 11 44 > 40 7 28 10 40 Sex Male 21 84 15 60 .052 Female 4 16 10 40 Past Medical History HTN Yes 13 52 15 60 .0569 No 12 48 10 40 DM Yes 6 24 4 16 .149 No 19 76 21 84 Seizure Yes 0 0 2 8 No 25 100 23 92 Surgery Duration (hours) 3-3.9 6 24 10 40 .322 4-4.9 13 52 8 32 5-5.9 6 24 7 7 Abbreviations: HTN, hypertension; DM, diabetes mellitus Bolus injection versus infusion of furosemide in transplantation-Zomorrodi et al. Kidney Transplantation 3014 in infusion group (P = .879, Table 1). There was no significant difference between the two groups regard- ing heart rate and systolic and diastolic blood pressures before and 120 minutes after anesthesia induction (Ta- ble 2). Diuresis duration was measured after arterial declamping. Its averages were 5.41 ± 3.7 minutes and 9.36 ± 7.65 minutes in bolus and infusion groups (P = .040). There was no significant difference between the two groups in terms of urinary output since the arteri- al anastomosis until four days after it, postoperatively Table 2. Heart rate, systolic and diastolic blood pressure of patients before induction and during surgery Heart Rate Systolic Blood Pressure Diastolic Blood Pressure Time (minutes) Study Groups Mean SD P Value Mean SD P Value Mean SD P Value Before induction Bolus 84.25 15.81 .125 151 17.4 .117 91.7 13 0.76 Infusion 80.69 23.34 140.6 26.5 85.47 18.3 0-15 Bolus 83.08 17.75 .419 136.8 22.4 .59 85.7 15.8 .120 Infusion 79.54 11.68 125 16.4 79.6 14.8 16-30 Bolus 78.08 15.02 .497 138.2 19.2 .052 89.5 14 .102 Infusion 80.83 12.7 128.7 13 84.8 12.2 31-45 Bolus 79 16.77 .678 127.1 13.9 .875 75.8 13.1 .685 Infusion 80.08 14.19 126.4 16.7 77.2 10.7 46-60 Bolus 86.5 19.21 .395 130.3 14.9 .134 75.3 9.5 .770 Infusion 82.16 15.54 123.4 16.4 77.2 11.9 61-75 Bolus 90.39 17.55 .580 131.3 14.7 .300 75.3 9.8 .451 Infusion 87.6 16.27 126.7 14.7 74.4 10.7 76-90 Bolus 91.78 17.69 .727 131.9 10.1 .212 74.6 11.2 .959 Infusion 93.7 16.15 127 14.2 74.8 8.6 91-105 Bolus 88.5 17.38 .218 135 12.2 .818 76.8 11.2 .230 Infusion 95.29 15.96 136.1 17.8 81.2 11.1 106-120 Bolus 89.47 19.87 14.03 133.1 11.9 .433 75.8 13.7 .206 Infusion 95 14.03 139 24.8 82.2 13.6 Figure 1. Patients' flow diagram Bolus injection versus infusion of furosemide in transplantation-Zomorrodi et al. Vol 14 No 02 March-April 2017 3015 (Table 3). Furthermore, there was no significant differ- ence in electrolyte levels before and four days after the surgery between both groups (Table 4). DISCUSSION In human kidney transplantation, attaining good imme- diate homograft function is an important factor for its ultimate success. When this is achieved, there will be massive postoperative diuresis along with improvement in the patient’s general condition.(6) One way to trigger diuresis is using diuretics such as furosemide. Most of the participants of our study were men in their fourth decades of lives. In similar studies the majority of patients have been men with the age range of 30-40 years old.(7,8) This is the range in which the person is ac- tively present in the society and kidney transplantation can significantly impact his/her life quality. In this study, it was observed that the bolus injection of furosemide increased the urinary output in kidney transplanted patients, but it was not statistically sig- nificant. However, the diuresis initiation time reduced Table 3: Urine output of the patients since arterial anastomosis up to four days after the surgery Time Study Groups Mean SD P Value Anastomosis or one hour after surgery Bolus 568 322.06 .811 Infusion 542.8 412.31 2-3 hours after surgery Bolus 1924 1131.1 .118 Infusion 1472 818.13 4-6 hours after surgery Bolus 3086 1127 .151 Infusion 2682.25 776.1 7-9 hours after surgery Bolus 3186 466.2 .100 Infusion 2597.91 588.3 10-12 hours after surgery Bolus 2558 831.6 .154 Infusion 2264.58 553.9 2nd day after surgery Bolus 11883.6 6522.7 .871 Infusion 1211875 2794 3rd day after surgery Bolus 7594 2986 .776 Infusion 7816 2429.7 4th day after surgery Bolus 5224 1821.4 .798 Infusion 5335.83 1119 Creatinine Urea Nitrogen Sodium Potassium Time Study Groups Mean P value Mean P value Mean P value Mean P value Preoperative Bolus 6.93 .207 94.69 .210 137.18 .132 4.91 .154 Infusion 7.86 115 139.72 4.43 Surgery day Bolus 4.95 .944 75.5 .577 136.6 .122 4.58 .217 Infusion 4.99 82.7 139.37 4.2 1st day after surgery Bolus 3.3 .337 65.88 .334 138.76 .769 4.13 .641 Infusion 3.22 77.65 139.16 4 2nd day after surgery Bolus 1.47 .146 62.64 .953 138.72 .721 3.96 .841 Infusion 1.79 61.91 138.12 3.92 3rd day after surgery Bolus 1.31 .061 62.6 .597 138.5 .971 4.14 .209 Infusion 1.75 56.87 138.54 3.77 4th day after surgery Bolus 1.55 .920 64.56 .396 139.52 .244 4.57 .244 Infusion 1.6 55.04 132.65 3.99 Table 4. Patients’ electrolyte level before and four days after the surgery Bolus injection versus infusion of furosemide in transplantation-Zomorrodi et al. Kidney Transplantation 3016 significantly. In a study by Lachance and colleagues the urinary output was 2.2 liters per day in patients who had received furosemide and 1 liter per day in their control group (who had not received furosemide) (P < 0.05). So, furosemide had increased the urinary output.(9) Raz- zaghi and colleagues reported that urine outputs were significantly higher in one, four, and 24 hours after transplantation in Lidocaine receiving group than furo- semide receiving group (P < .001). In a meta-analysis, Alqahtani and colleagues found that in eight examined cases, there was no significant difference in urinary out- put of patients who had received furosemide by bolus or infusion. But in eight other cases, the urinary output was significantly higher in patients who had received continuous furosemide than in those who had received furosemide frequently.(11) We did not find any other similar studies in the literature. So, most studies sup- port the furosemide bolus administration. This method, in comparison with infusion method, was able to further precipitate the diuresis onset. In our study, no significant difference was observed in the levels of sodium, potassium, blood urea nitro- gen, and creatinine between the two studied groups. Lachance and colleagues reported that furosemide sig- nificantly reduced creatinine level in kidney transplant- ed patients compared to their control group (who had not received furosemide).(9) In Razzaghi and colleagues’ study, which compared the continuous injection versus bolus administration of furosemide in patients with heart failure, it was observed that furosemide injection increased creatinine level in the bolus group by 0.8 mg/ dl and decreased it in the infusion group by 0.8 mg/dl (P < .001). In addition, the level of glomerular filtra- tion rate decreased by 9 mL/min/1.73 m2 in their bolus group and was increased by 6 ml/min/1.73 m2 in their infusion group (P < .05).(10) In Palazzuoli and colleagues’ study, it was observed that patients who had received continuous dosages of furosemide had higher serum creatinine level and low- er glomerular filtration rate compared to those who re- ceived bolus dosages. Furosemide can contribute con- siderably to electrolyte excretion and serum creatinine level reduction by increasing glomerular filtration rate. (12) In our study, furosemide administration method did not change electrolyte level. A limitation of our study was lack of a control group to measure the amount of urine output without receiving furosemide. CONCLUSIONS Bolus injection of furosemide can reduce diuresis onset time compared to furosemide infusion. ACKNOWLEDGEMENTS This study is based on a thesis of Tabriz University of Medical Sciences. The authors would like to thank Hassan Soleimanpour for the preparing this manuscript. Also, they would like to thank Seyed Muhammed Hus- sein Mousavinasab for his sincere cooperation in edit- ing this text. CONFLICT OF INTEREST None declared. REFERENCES 1. Tanabe K, Takahashi K, Toma H. Causes of long-term graft failure in renal transplantation. World J Urol. 1996; 14: 230-5. 2. 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Continuous versus bolus intermittent loop diuretic infusion in acutely decompensated heart failure: a prospective randomized trial. Crit Care. 2014;18:134. Vol 14 No 02 March-April 2017 3017 Bolus injection versus infusion of furosemide in transplantation-Zomorrodi et al.