Acute renal failure

Acute renal failure (ARF) is a clinical syndrome characterized by rapid deterioration of renal function that results in the accumulation of nitrogenous wastes. This syndrome complicates the hospital course of 5% of hospitalized patients and 30% of patients admitted to the ICU. As an isolated organ system failure, ARF carries a low mortality of ~8%. However, ARF that accompanies multi-organ system failure, as is usually the case in the critically ill surgical patient, carries a much poorer prognosis. For example, ARF as part of two-organ system failure has a mortality of 75%. The mortality increases to 90-100% with involvement of more than two organs. The outcome of ARF is most often linked to the resolution of the patient's underlying problems. However, prompt recognition and management of renal failure is critical to improving patient survival. The terminology regarding ARF is confusing and selected terms are defined in Table 1.