Protein-energy requirements in subjects with acute renal failure receiving intermittent hemodialysis

Abstract

Parenteral nutrition may reduce morbidity and mortality in acute renal failure. Ideally, negative protein (nitrogen) balance would be reversed. However, the intake of glucose and amino acids required to achieve positive balance have not been determined. We therefore examined the effects on protein balance of widely varying intakes of amino acids and hypertonic glucose in 14 acute renal failure patients receiving hemodialysis. Because plasma solute concentrations change continuously, a single compartment mathematical model was used to derive urea nitrogen losses from the urea nitrogen generation rate (Gun). During 32 study periods (averaging 6 days each), nutrient intake was maintained stable. Protein balance was then estimated from the amino acid nitrogen intake minus the Gun. On average, Gun (11.2 ± 1.8 g/day) exceeded amino acid nitrogen intake (6.0 ± 1.2 g/day) by 5.6 ± 1.6 g/day, indicating negative protein balance. The high Gun is consistent with hypercatabolism in these subjects. Increased nutrient intake correlated significantly with improved protein balance for both the intake of glucose (r = 0.64) and amino acid nitrogen (r = 0.50). Nonetheless, protein balance became transiently positive in only four subjects, at which time the amino acid intake averaged 1.03 g/kg per day and glucose intake, 50 kcal/kg per day. We conclude that in hypercatabolic acute renal failure, protein and energy requirements considerably exceed those conventionally prescribed.