Changes of plasma amino acids in total parenteral nutrition-supported patients with intraabdominal infection

Plasma aminogram changes were prospectively studied in 95 patients with external enteric fistula and intraabdominal infection who were under total parenteral nutrition (TPN) therapy with anfuming 14s. Plasma amino acids and albumin were determined before the administration of TPN, weekly and at the end of the therapy or 2 to 5 days before death of patients. In patients with sepsis and starvation, the aminogram showed remarkably low total free amino acids before TPN therapy. In survivors, free amino acids increased gradually to normal in 2 weeks after use of TPN and in the dead increased rapidly to a significantly high peak at the terminal stage. In both survivors and deceased, phenylalanine level remained high during the study. In response to infection, proline was also elevated but to a lesser degree; the ratio of branched chain amino acid (BCAA) to aromatic amino acid (AAA) was lower than normal and the decrease of arginine was parallel to the severity of infection. We conclude that the ideal amino acid preparation for the starved, septic patients should be high in BCAA and arginine but low in phenylalanine; the administration of inappropriate exogenous amino acids in metabolically decompensated septic patients may bring about more harm than benefit; and in septic patients the persistently elevated level of plasma phenylalanine and proline along with decrease of arginine is a useful prognostic sign.