Nutritional Aspects in Acute Renal Failure Following (Cardiac) Surgery

摘要

Total parenteral nutrition has been reported to reduce morbidity and mortality in patients with acute renal failure. Adequate therapeutic guidelines to provide optimal intake of amino acids and glucose have yet to be defined. For this reason, the applicability of a mathematical model to UN and NPN kinetics in patients developing acute renal failure following open heart surgery was examined. During 32 study periods (averaging 6 days each) nutrient intake was maintained stable. However, the patients received widely varying intakes of amino acids and glucose. Protein nitrogen balance was estimated from the amino acid nitrogen intake minus the kinetically determined UN or NPN generation rate. On an average, UN generation rates (11.2 plus or minus 1.8 g/day) exceeded amino acid nitrogen intake (6.0 plus or minus 1.2 g/day) by 5.6 plus or minus 1.6 g/day, indicating negative protein balance. The high generation rates indicated hypercatabolism. Increased nutrient intake correlated significantly with improved protein nitrogen balance for both glucose intake (r=0.64) and amino acid intake (r=0. 50). Nonetheless, protein nitrogen balance became transiently positive in only 4 subjects, at which time amino acid intake averaged 1.0 g/kg/day and glucose, 50kcal/kg/day. The calculated generation of UN, and NPN, closely matched actual amounts of UN and NPN removed in validation studies. It is concluded that, in hypercatabolic acute renal failure, protein and energy requirements considerably exceed those conventionally prescribed.