Evaluation of parenteral nutrition in the postoperative patient.

A variety of investigators have attempted to improve nitrogen balance during the postoperative period by modifying the composition of the infused nutrient solutions. This study compared the metabolic effects of administering standard amino acid solutions with a solution enriched with branched chain amino acids (BCAA). A prospective, randomized clinical study was performed in patients who had undergone subtotal gastrectomy or hemicolectomy, and subsequently cared for in the metabolic care unit. The patients were selected from specific entry criteria so that two groups of individuals were comparable. All patients underwent operation without complications. The plasma concentrations of valine and leucine were significantly increased (p less than 0.05 and p less than 0.01, respectively) two days after administration of solutions enriched with BCAA and throughout the entire postoperative period. The plasma glutamine concentrations tended to decrease in both groups; no concentration difference occurred between groups. Nitrogen balance tended to be more positive in the group receiving BCAA but there was no significant difference between groups after operation. Urinary excretion of 3-methylhistidine tended to increase postoperatively in both groups, but no difference occurred between groups. However, the urine excretion of isoleucine increased significantly in the patients receiving infusions enriched with BCAA. Both standard balanced amino acid and amino solutions enriched with BCAA were well tolerated in all patients.