Nutritional management of acute renal failure

The principles of nutritional therapy (ie, maintain lean body mass, stimulate immunocompetence, and repair functions, such as wound healing) are similar for patients with acute renal failure (ARF) and with other catabolic clinical conditions. However, if a patient with ARF requires nutritional support, the multiple metabolic consequences of acute uremia must be taken into account. These do not only affect fluid, electrolyte, and acid-base balance but also the metabolism of amino acids, proteins, carbohydrates, and lipids. In addition, these metabolic alterations are modified by the acute disease process per se, by associated complications (such as severe infections), and last but not least, by the type and intensity of renal replacement therapy. Whenever possible, enteral nutrition should be provided in patients with ARF because even small amounts of luminal nutrients will help to maintain intestinal functions. Nevertheless, in many patients a parenteral nutrition, at least supplementary and/or temporarily, will become necessary. Metabolic complications of nutritional support frequently occur in patients with ARF because tolerance to volume load and electrolytes is limited and the use of various nutrients is impaired. Despite the notorious difficulty to demonstrate clear-cut benefits of nutritional interventions and especially, of parenteral nutrition on prognosis in critically ill patients, there can be no doubt that nutritional therapy presents a cornerstone in the treatment of patients with ARF. Preexisting and/or hospital-acquired malnutrition have been identified as important factors contributing to the persisting high mortality in acutely ill patients with ARF.