Effect of Furosemide under Hyperchloremic Acidosis on Intraoperative Oliguria and Acute Kidney Injury in Patients with Normal Renal Function

Background: Renal function tends to deteriorate in a hyperchloremic acidifying environment, which is reflected by a decrease in the difference between sodium and chloride. Objectives: To examine the effect of furosemide administered under hyperchloremic acidosis on intraoperative oliguria and acute kidney injury in patients with preoperatively normal renal function. Methods: In patients undergoing abdominal or orthopedic surgeries (April 2010–November 2018), we retrospectively identified patients who preoperatively had a normal renal function but experienced intraoperative oliguria under hyperchloremic acidosis (a sodium-chloride difference < 30 mEq/L) without dehydration. We compared the perioperative urine output and the incidence of postoperative acute kidney injury between patients who intraoperatively received an initial dose of 5 mg of furosemide (the furosemide group) and patients who did not intraoperatively receive furosemide (the control group). Results: We identified 62 patients in the furosemide group and 48 patients in the control group. The furosemide group intraoperatively received 0.11 ± 0.06 mg/kg of furosemide (range 0.06–0.39 mg/kg). Compared to the control group, the furosemide group had greater urine output (mL/kg/h) in the operating room (1.1 ± 0.7 vs. 0.3 ± 0.1, p < 0.01) and on postoperative day 1 (1.2 ± 0.5 vs. 1.1 ± 0.4, p = 0.02). The incidence of postoperative acute kidney injury was lesser in the furosemide group than that in the control group (8.0 vs. 27.0%, p < 0.01; multivariate OR 0.18; 95% CI 0.05–0.61; p < 0.01). Conclusions: In surgery patients under hyperchloremic acidosis, furosemide (0.1 mg/kg) resolved intraoperative oliguria and reduced the incidence of postoperative acute kidney injury.