Defining oliguria during cardiopulmonary bypass and its relationship with cardiac surgery–associated acute kidney injury

While urine flow rate ≤0.5 ml kg−1 h−1 is believed to define oliguria during cardiopulmonary bypass (CPB), it is unclear whether this definition identifies risk for acute kidney injury (AKI) . The purpose of this retrospective study was to evaluate if urine flow rate during CPB is associated with AKI. Urine flow rate was calculated in 503 patients during CPB. AKI in the first 48 h after surgery was defined by the Kidney Disease: Improving Global Outcomes classification. Adjusted risk factors associated with AKI and urine flow rate were assessed. Patients with AKI [n=149 (29.5%)] had lower urine flow rate than those without AKI (P