Rupa Anna, Abraham (2011) A Randomized Controlled Clinical Trial to study the Renoprotective effect of Sodium Bicarbonate Infusion in patients undergoing Open Heart Surgeries. Masters thesis, Christian Medical College, Vellore.
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Abstract
INTRODUCTION: Acute renal dysfunction is a common and serious postoperative complication of cardiopulmonary bypass and may affect 25% to 50% of patients. Acute renal failure is related to preoperative renal function as well as to the presence of coexisting disease. Cardiopulmonary bypass also may affect renal function adversely because the unphysiologic state of nonpulsatile flow may upset the normal autoregulatory mechanisms of renal blood flow. Acute renal dysfunction also carries significant costs. and is independently associated with increased morbidity and an increase in mortality. Urine acidity may enhance the generation and toxicity of reactive oxygen species induced by cardiopulmonary bypass. Activation of compliment during cardiac surgery may also participate in renal injury. Urine alkalinisation may protect from renal injury induced by oxidant substances, iron mediated free radical pathways, complement activation and tubular hemoglobin cast formation. Accordingly we want to study whether urine alkalinisation might protect kidney functions in patients at increased risk of renal dysfunction undergoing cardiopulmonary bypass by sodium bicarbonate infusion. This study is a randomized controlled trial to see if sodium bicarbonate infusion is helpful in preventing increase in serum creatinine after cardiopulmonary bypass. A group of 100 patients at increased risk of post operative renaldysfunction are randomized to either 24 hours of iv infusion of sodium bicarbonate or sodium chloride and serial serum creatinine values to be taken for five consecutive days. The primary outcome is the proportion of patients developing acute renal dysfunction defined as postoperative increase in plasma creatinine >25% of the baseline within the first five post operative days. We also looked for increase in plasma urea levels >25% of baseline within the first five days .Also for side effects of sodium bicarbonate infusion like hypernatremia, hypokalemia, and metabolic alkalosis. AIM OF THE STUDY: The aim of the study is to test whether perioperative sodium bicarbonate infusion can attenuate post operative increase in serum creatinine in cardiac surgical patients. This is done by studying the 1. Proportion of patients developing acute renal dysfunction defined as postop increase in serum creatinine >25% of baseline within first 5 postop days. 2. Proportion of patients developing blood urea >25% of baseline within first 5 days. 3. Proportion of patients developing complications like alkalosis, hypokalemia and hypernatremia. METHODOLOGY: Design overview: This study was a double blind, single centre, randomized controlled trial. The human research ethics committee, CMC Vellore approved this study. Written informed consent was obtained from each patient. Setting and participant: Patients were identified in the hospital wards. We enrolled patients at increased risk of postoperative acute renal dysfunction who were scheduled for elective cardiac surgery necessitating the use of cardiopulmonary bypass. All surgical approaches were by median sternotomy. The cardiopulmonary bypass circuit consisted of a roller pump, tubing, a membrane oxygenator and an arterial filter . The pump priming solution consisted of 700 ml of Ringer lactate, 500 ml of Haesteril with 50 ml of 20% Mannitol. Perioperative bypass management targeted a cardiac output of >2.5 l/min/m2 and a mean arterial blood pressure of 40-60 mm hg . The use of intraoperative fluid management was left to the discretion of the anaesthetist. Analgesia was achieved with opioids like fentanyl and morphine with avoidance of nonsteroidal anti-inflammatory drugs. Urine output was maintained at >0.5 ml/kg/hr. Method of randomization: Randomisation codes were generated using block randomization method with size of 2, 4 and 6. Method of allocation concealment: The sequence was generated by the statistician and the allocation codes were serially numbered and sealed in opaque envelopes which were handed over to the anaesthesia technician just before the surgery. He loaded the drugs accordingly. RESULTS: Between march 2010 and july 2010 we randomized 100 patients to receive intravenous sodium bicarbonate A group(n=50) or sodium chloride B group (n=50). Two sample t test with equal variances were used for statistical analysis. The mean age in both the study and control groups were comparable Group A being 49.6 and Group B being 48.0 years.There were no differences in both the groups in baseline characteristics like age and sex as seen above in Table 1 and 2. Out of the 50 in sodium bicarbonate group 13 were >=60 years .Out of the 50 in the placebo group 14 were more than 60 years of age .Out of the 50 in A group 30 were males and out of the 50 patients in B group 34 were females which was again not significant .There were no significant difference in the baseline characteristics like blood urea and serum creatinine .All patients had elective cardiac surgery either a CABG or a valve replacement. CONCLUSIONS: 1. There is a significant 40-50% incidence of patients developing acute renal dysfunction after cardiopulmonary bypass in the high risk group. 2. Sodium bicarbonate infusion did not cause any decrease in incidence of renal dysfunction in cardiac surgical patients. 3. Sodium bicarbonate infusion was useful intraoperatively to decrease the incidence of metabolic acidosis otherwise associated with cardiopulmonary bypass. 4. None of the patients developed side effects like hypernatremia, hypokalemia, and perioperative arrhythmias which was statistically significant.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Renoprotective effect ; Sodium Bicarbonate Infusion ; patients ; undergoing Open Heart Surgeries ; Randomized Controlled Clinical Trial. |
| Subjects: | MEDICAL > Anaesthesiology |
| Depositing User: | Subramani R |
| Date Deposited: | 30 Apr 2018 02:54 |
| Last Modified: | 30 Apr 2018 02:54 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/7325 |
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