Variations in plasma amino acids in septic patients subjected to parenteral nutrition with a high proportion of branched-chain amino acids.

Sepsis is characterized by an increase in the plasma concentration of aromatic amino acids (AAAs) and those containing sulfur and a decrease in the branched-chain amino acids (BCAAs). We studied changes in the plasma aminogram of septic patients given different types of total parenteral nutrition (TPN), analyzing variations in accordance with the type of TPN used and the importance that the use of BCAA may have in these patients. We studied 80 patients with peritonitis divided into two groups of 40 patients each: group 1 was given a solution with 22.5% BCAA and group 2 a solution with 45% BCAA. High BCAA content caused an increase in the plasma concentrations of these amino acids and in the BCAA/AAA quotient and a decrease in AAAs. Plasma concentrations of leucine and valine reached high, potentially toxic levels at 15 days when solutions with high BCAA content were used. Glycine increased in group 1, which may be important because of its tendency to produce hyperammonemia. BCAAs are of unquestioned nutritional importance in view of the evidence of changes that take place in muscle protein catabolism and in plasma amino acids. In the phase of increased protein catabolism, we saw a plasma amino acid pattern in keeping with the existing metabolic situation. The need for BCAA diminishes when the hypercatabolic state disappears.