Role of Loop Diuretic Challenge in Stage 3 Acute Kidney Injury

Objective: To assess whether loop diuretic challenge predicts the need for dialysis among critically ill patients with acute kidney injury (AKI) stage 3. Patients and Methods: Adult patients admitted to intensive care units between January 1, 2004, and December 31, 2016, were screened. Acute kidney injury stage 3 was identified by an electronic surveillance tool, and patients who received loop diuretics in a dosage of at least 1mg/kg intravenous bolus furosemide equivalent were included. Urine output following loop diuretic challenge was modeled as a restricted cubic spline. We then compared the area under the receiver operating characteristic curve for urine outputs at 2 hours and 6 hours after loop diuretic challenge to predict the need for dialysis within the next 24 hours. Results: Of 687 patients included in the study, those who received dialysis were younger and had higher Sequential Organ Failure Assessment scores on the day of loop diuretic challenge. Urine outputs at 2 hours and 6 hours were lower in patients who needed dialysis, but urine output by 6 hours was better in predicting dialysis initiation within 24 hours (area under the curve, 0.71 vs 0.67; P=.02). The sensitivity and specificity of 6-hour urine output cutoff of 600 mL or less to predict dialysis was 80.9% and 50.5%, respectively, and that for 300 mL or less was 64.2% and 68.2%, respectively. Conclusion: Among patients with stage 3 AKI, 6-hour urine output after the loop diuretic challenge had a modest discriminant capacity to identify dialysis initiation within the next 24 hours.