Prerenal failure: from old concepts to new paradigms.

PURPOSE OF REVIEW: Prerenal failure is used to designate a reversible form of acute renal dysfunction. However, the terminology encompasses several different conditions that vary considerably. The lack of a widely accepted definition for prerenal failure makes it impossible to determine the epidemiology, natural history, and association with adverse outcomes. RECENT
FINDINGS: New diagnostic and staging criteria for acute kidney injury proposed by the Acute Kidney Injury (AKI) Network recognize that small increases in serum creatinine are associated with increased mortality. However, these criteria have not determined specific diagnostic criteria to classify prerenal conditions. As a consequence of the lack of standardized definitions and the difficulty in assessing reversibility of AKI, the concept of prerenal failure has been recently challenged. The difference in the pathophysiology and manifestations of prerenal failure suggests that our current approach needs to be reevaluated.
SUMMARY: Prerenal failure state needs to be classified depending on the underlying capacity for compensation, the nature and the timing of the insult and the adaptation to chronic comorbidities. Identification of high-risk states and high-risk processes associated with the use of new biomarkers for AKI will provide new tools to distinguish between the prerenal failure and the established AKI. This review provides an appraisal of the current status and recommendations for future research in this field.