Comparing the protective effect of ascorbic acid and sodium bicarbonate in the prevention of acute renal complication after cardiac surgery using cardiopulmonary bypass

Background: Many methods have been used to prevent acute postoperative renal complication in cardiac surgery, with various results. The purpose of the present study was to compare ascorbic acid versous isotonic sodium bicarbonate in the prevention of acute postoperative renal complication in adult cardiac surgery using cardiopulmonary bypass (CPB).

Methods: In a clinical trial, 150 adult patients scheduled for elective cardiac surgery using CPB, enrolled to this study in three ascorbic acid, sodium bicarbonate and placebo groups (each group=50). During surgery, 1000 ml of normal saline was infused in a 2 hours period that contain ascorbic acid 500mg, sodium bicarbonate 8.4% 75 ml or saline alone, respectively. Invasive hemodynamic and urinary output monitoring was done intra and post-operatively. An increase more than 0.5mg/dl or more than 25% in basic plasma creatinine (Cr) or decrease more than 25% in basic glomerular filtration rate (GFR), was considered as acute kidney injury (AKI). An increase or decrease of more than 50% in basic Cr or GFR, respectively, was considered as acute renal failure (ARF). Data were analyzed using X2, student t-test and ANOVA tests.

Results: AKI and ARF were occurred in 36 and 9 patients, respectively (P=0.043 and P=0.001, respectively), those were lesser in ascorbic acid group The renal protective effect of the ascorbic acid occurred for longer period than bicarbonate.

Conclusion: Comparing to sodium bicarbonate and placebo groups, ascorbic acid is more effective in prevention of the acute postoperative renal complication in adult cardiac surgery using CPB.