Acute kidney injury classification: AKIN and RIFLE criteria in critical patients

Abstract

Acute kidney injury (AKI) is a common and serious complication in critically ill patients. The mortality rate remains high despite improved renal replacement tech-niques. A possible cause of the high mortality rate is that intensive care unit patients tend to be older and more debilitated than before. Pathophysiological factors associated with AKI are also implicated in the failure of other organs, indicating that AKI is often part of a mul-tiple organ failure syndrome. Until recently, there was a lack of consensus as to the best definition, character-ization, and evaluation of acute renal failure. This lack of a standard definition has been a major impediment to progress in clinical and basic research. The introduc-tion of the risk, injury, failure, loss, and end-stage kid-ney disease criteria and the modified version proposed by the Acute Kidney Injury Network have increased the conceptual understanding of AKI syndrome, and these criteria have been successfully tested in clinical stud-ies. This article reviews current findings concerning the application of these criteria for assessing epidemiology and predicting outcome in specific homogeneous criti-cally ill patient groups.