Acute renal failure in the postoperative period is appallingly common and has abysmal outcomes. In high-risk populations the incidence may be as high as 25%, and patients who require critical care services and renal replacement therapy have repeatedly been shown to have a mortality rate >70%. Despite this, perioperative resuscitation strategies are frequently formed solely with cardiac and pulmonary outcomes in mind. An early extubation is a pyrrhic victory if it condemns the patient to a slow death or lifetime dialysis. Despite decades of research, the risk factors, etiology, prevention, and treatment of perioperative acute renal failure all remain murky. Numerous interventions have been assessed, with few promising results. There are a few tools at hand, though, and the devastating effect of acute renal failure obligates anesthesiologists to use the tools available with the best possible dexterity.

The most consistent risk factor for perioperative renal failure is preoperative renal dysfunction. Elevated creatinine or decreased creatinine clearance, or a preoperative diagnosis of renal insufficiency, all significantly increase the risk of postoperative renal failure. Preoperative heart failure and diabetes mellitus are also significant predictors, as are the acute comorbidities rhabdomyolysis, fulminant liver failure, abdominal compartment syndrome, and sepsis. Surgical procedures involving cardiopulmonary bypass or aortic cross-clamp (any aortic cross-clamp, not just suprarenal clamping) increase risk as well. Perioperative diagnostic studies involving nephrotoxic radiocontrast and medical management of concurrent nonsurgical disease (chemotherapy, aminoglycosides, nonsteroidal anti-inflammatory drugs [NSAIDs]) can further elevate the risk.

Anesthetic management directed at preventing acute renal failure ranges from banal to complex. If possible, stop nephrotoxic medications preoperatively. Certainly do not give preoperative NSAIDs to improve analgesia in at-risk patients. For procedures that will take 2 hours or more, a Foley catheter should be placed. Ensure that urine enters the Foley catheter when it is placed, as a misplaced Foley and subsequent obstruction can cause renal failure. In current practice there is no longer a fixed “goal” for hourly urine output; the objective is to monitor urine output diligently, and if it drops, intervene—increase perfusion pressure, give a fluid challenge, and inform
the surgeon. If need be, place a central venous pressure (CVP) monitor to assure adequate intravascular volume. Eschew nephrotoxic agents in your anesthetic plan: ketorolac, dextran, and aminoglycosides should be avoided. It is clear that hypoperfusion contributes to perioperative renal failure; in at-risk patients, maintaining perfusion pressure is a high priority. Have a low threshold for placing an intra-arterial monitoring line, and use vasoactive agents, if necessary, to treat hypotension.