[Acute renal insufficiency: nutrition disorders and therapeutic consequences]

Catabolism is usually enhanced in acute renal failure (ARF). Its magnitude varies from one patient to another and can change significantly in the same patient from day to day, reflecting its clinical course. It depends on the severity of the ARF, the underlying process, the associated co-morbidity, and therapeutic approach. The detection of patients at high risk for malnutrition is extremely important; nutritional markers and indexes of caloric and protein requirements are useful to adapt renal replacement and nutritional support to ARF patients. Various biochemical parameters (namely, serum albumin and prealbumin), anthropometic measures, indirect calorimetry, urea and creatinine kinetics are all useful tools to evaluate metabolic status and requirements nutritional. Commonly, the caloric requirements are nearly 35 kcal/kg/24 h with correction factors applied for certain clinical situations: carbohydrates account for 50 to 60% of those needs whereas lipids account for the rest. The total amount of fluid administered has to be adapted to the possible ultrafiltration achieved by dialysis. Daily dialysis sessions and continuous renal replacement therapy allow larger volumes and thus facilitate nutritional support. Protein needs frequently exceed 1.2 g/kg/24 h to maintain the nitrogen balance, with a calorie to protein ration close to 150 kcal per g of nitrogen. Sufficient amounts of vitamins and oligo-elements are necessary. Stimulating anabolism by exogenous mediators, such as androgenic hormones or growth factors (rh-IGF1, rh-GH) is an avenue that deserves better definition in critically ill ARF patients.