Metabolic studies in severe burns. Clinical features, routine biochemical analyses, nitrogen balance and metabolic rate.

The effects of two isocaloric regimens for parenteral nutrition were compared on days 2 to 8 after severe burns in 16 patients. Energy expenditure, plasma catecholamines, biochemical variables and N-balance were measured. The 8 patients in group I, with mean burn size 55/25%, received fat and glucose, while the 8 in group II, mean burn size 60/40%, were given 24 g amino acid nitrogen daily in addition to the fat and glucose. The mean metabolic rate on days 2-8 after burning was 70 +/- 7 and 69 +/- 5 kcal/m2/h in groups I and II, respectively. The mean values for plasma noradrenaline in the same period were 8.35 +/- 0.89 and 7.9 +/- 0.77 nmol/l. The biochemical changes showed a pattern typical of burns. There were no intergroup differences except for urea, which was significantly higher in the group (II) receiving amino acids. The cumulative N-balance was markedly less negative 8 days after trauma (-24 g N +/- 8 g) in group II than in group I (-100 g N +/- 10 g). These results indicate that a high nitrogen intake, together with adequate energy supply, improves the N-balance significantly in the early post-burn period. The high-energy supply from fat and glucose did not seem to cause the patients additional stress.