NUTRITIONAL MARKER AND SKELETAL-MUSCLE BR EAKDOWN IN SEVERELY BURNED PATIENTS - COMPARATIVE EFFECTIVENESS OF SMALL PEPTIDES OR FREE AMINO-ACIDS

The beneficial effects of hight caloric and protein enteral diet on wo und healing and prevention of infection in severly burned patients is well documented. However, the relative proportion of each nutrient and especially the form of nitrogen supply have not yet been clearly esta blished. The aim of this study was to compare, in severely burned pati ents, the efficiency of a partial protein hydrolysate and free amino a cid formula during a 15-day enteral feeding. Twenty burned patients ra nging in age from 18 to 67 years with a mean burn size of 40 +/- 12 % of total body surface area, of which 31 +/- 14 % was deep dermal, were studied prospectivly and randomised in two groups. Group A received t he free amino acid diet which was obtained by hydrolysis of the protei n hydrolysate given to Group B (60 % small peptides). Ail diets contai ned a nitrogen source of similar amino acid composition. Nitrogen bala nce was measured daily and serum protein concentrations were determine d on days 0, 4, 8, 11 and 15. Anthropometric parameters, urinary 3 met hylhistidine/creatinine ratio and plasma amino acid concentration were assessed on days 0, 8 and 15. Daily and cumulative nitrogen balance a t D15 did not differ between the two groups. In group A, the circulati ng visceral proteins increased at all times of the study without decre ase of acute phase reactant, whereas only transthyretin and retinol bi nding protein increased at D11 and D15 with a significant decrease of C-reactive protein at the same time in the other group. In group A, th e musculary circumference had decreased at D8 and D15 without change o f the 3 methylhistidine/creatinine ratio, whereas in group B the anthr opometric parameters did not change with a decrease of the 3 methylhis tidine/creatinine ratio at D8. Comparisons of D8 or D15 with DO values showed that 14 amino acids, from which 6 essential amino acids increa sed significantly with the free amino acid diet, but only one amino ac id increased with the protein hydrolysate diet. We conclude that in se verely burned patients, enteral feeding with small peptides decreases muscular breakdown without change in hepatic protein synthesis. The en teral support containing free amino acids is more effective on serum p rotein levels, probably by increasing the production of endogenous ami no acids.