Incidence, trends, and diagnosis of perioperative acute kidney injury

The incidence of all postoperative acute kidney injury (AKI), including the subset requiring dialysis, is increasing. Modern definitions for AKI, including Risk, Injury, Failure, Loss, and End-Stage Kidney Disease (RIFLE), Acute Kidney Injury Network (AKIN), and Kidney Disease: Improving Global Outcomes (KDIGO), have increased sensitivity and have standardized understanding of AKI, allowing improved epidemiologic study. The reported incidence of AKI following cardiac surgery historically has varied by AKI definition from <1.5 % for cases requiring dialysis to 25 % when AKI is defined as a rise in creatinine of 25 %. AKI rates in noncardiac surgery are significantly lower with the exception of patients in the intensive care unit and those receiving solid organ transplants. Despite rising AKI incidence, multiple studies have found mortality rates in postoperative patients with AKI to either be stable or falling.