The nutritional management of acute renal failure in the critically ill patient

Because of its peculiar metabolic features and because of the difficulties associated with its control in acute renal failure (ARF) patients, the uremic state has traditionally been considered unique from the nutritional point of view. The administration of adequate amounts of nitrogen, in particular, has been hindered by the difficulties associated with conventional intermittent hemodialysis (IHD) in the critically ill and by the belief that ARF patients could be safely treated in a manner similar to that of chronic renal failure patients. However, protein malnutrition is the inevitable consequence of a low-protein nutritional regimen in critically ill patients with ARF. Such protein depletion and a persistent and markedly negative nitrogen balance are highly undesirable and result in respiratory muscle wasting and, possibly, immunological dysfunction and delayed renal recovery. The advent of continuous renal replacement therapies (CRRT} now permits the virtually unrestricted administration of nutrition and proteins to patients with ARF and critical illness. Studies recently conducted on the consequences of a higher protein intake in such patients indicate that nitrogen balance can be significantly improved with greater protein intake and that azotemia can always be controlled by CRRT. Special renal preparations of amine acids have so far failed to show any advantage over conventional preparations. Patients with severe ARF should receive the same nutritional support offered to other critically ill patients.