Background and Goal of Study
Acute kidney injury (AKI) following cardiac surgery is associated with inflammation, oxidative stress, and oxygen free radicals. Patients with infective endocarditis (IE) have a high risk of AKI due to systemic inflammation and infection. Sodium bicarbonate has intrinsic natriuretic effects and ability to alkalize tubular fluid, increasing oxygen delivery and reducing oxidative stress by free radical formation. We investigated whether perioperative sodium bicarbonate infusion could attenuate AKI in IE patients undergoing valvular heart surgery.  

Materials and Methods
Sixty IE patients undergoing cardiac surgery were randomly assigned to placebo (n = 31) or to bicarbonate (n = 29) groups. Sodium bicarbonate was administered at a loading dose of 0.5 mmol/kg for 1 h commencing with anesthetic induction, followed by an infusion rate of 0.15 mmol/kg/h for 23 h. The primary endpoint was the incidence of AKI during the first postoperative 48 h. Serum creatinine level and glomerular filtration rate during the postoperative 5 days, and major morbidity endpoints were assessed.

Results and Discussion
The incidence of AKI based on Acute Kidney Injury Network criteria was 7 (23%) in the control group and 9 (31%) in the bicarbonate group (P = 0.459). The group × time interactions on serum creatinine level and estimated glomerular filtration rate (eGFR) were not statistically significant between groups in the linear mixed-model analysis (P = 0.077 and 0.083, respectively). The incidences of major morbidity endpoints were not different between the groups.

Conclusion
Perioperative sodium bicarbonate administration was not found to reduce the incidence of AKI in IE patients undergoing cardiac surgery.

Effect of perioperative sodium bicarbonate on postoperative acute kidney injury in infective endocarditis patients