Catabolism in acute renal failure: Strategies for the application of aminoacids

Extensive Catabolism is a hallmark of patients with acute renal failure (AR F) complicating critical illnesses. Catabolism is due to dysregulation of p rotein metabolism as well as a consequence of deminished renal excretion an d renal replacement therapy (RRT). Inadequate nutritional support predispos es patients to-malnutrition and increased mortality risk. Since the catabol ic rate varies widely in ARF patients and can not be predicted by clinical parameters, direct quantification of the protein catabolic rate should be p erformed regularly. The urea nitrogen appearance rate (UNA) is a valid and reproducible estimate of nitrogen balance in critically ill patients underg oing continuous RRT. Amino acid losses up to 50 g/day and protein losses up to 15 g/day occur during continuous RRT and need to be compensated for. In order to achieve neutral or positive nitrogen balance a nutritional regime n providing 1.5-2.0 g protein/kg/day and 25-35 kcal/ kg/day may be required . Since glutamine losses during continuous RRT may exceed 4 g/day, glutamin e supplementation (0.3-05 g/kg/day) appears to be recommendable.