The development of acute renal failure (ARF)in the perioperative period continues to be a serious condition associated with high morbidity and mortality rates perioperative (ARF) results from many etiologies However more then 90% of cases is due to relative hypovolemia and inadequate renal perfusion a priority for anesthesia care providers is to limit perioperative renal impairment this process begins with the identification of patient at risk for perioperative renal dysfunction