Serum and erythrocyte amino acid pattern: studies on major burn cases.

Venous serum amino acids were measured in 13 patients with major burns. Erythrocyte amino acids and plasma cortisol, blood sugar and urine catecholamine were measured in two representative subgroups respectively. After burn injury, serum proline, glycine, valine, isoleucine and arginine were significantly decreased; phenylalanine, cysteine, methionine, leucine, glutamate, alanine, aspartic acid and tyrosine were significantly increased. Histidine and lysine fluctuated. This serum amino acid profile is considered as a specific pattern for major burns. Serum phenylalanine was markedly elevated in the hypermetabolic burn patients, its fluctuation coincided with the burn course and was negatively correlated with serum albumin level (P less than 0.001). These findings suggest that the ratio of phenylalanine tyrosine is a useful clinical parameter for assessing the patient's nutritional condition. Twenty-three simultaneous determinations of both serum and erythrocyte amino acid concentrations show similar changes, suggesting that the serum amino acid profile might reflect the change of total free amino acid pool. After burn injury, plasma cortisol, blood sugar and urine catecholamine were elevated as well as urine urea nitrogen. However, although the first three returned to normal by the end of the second week post burn, urine urea nitrogen remained high. This indicates that there are other factors controlling nitrogen loss in patients with major burns, it is also postulated that, due to the abnormal amino acid pattern revealed after major burns, the constituents of commercially available amino acid solutions should be modified.