Parenteral nutrition and coma therapy with amino acids in hepatic failure.

Abstract

Patients with liver cirrhosis show typical changes in plasma and brain amino acid levels. If symptoms of hepatic encephalopathy (HE) have not yet developed, the concentrations of phenylalanine and tyrosine are already enhanced. With increasing HE there is a rise in the levels of methionine and free tryptophan, valine, leucine and isoleucine are generally diminished. In order to conduct safe parenteral nutrition and coma therapy in hepatic failure corrective amino acid solutions have been proposed. In 103 cirrhotic patients, the effects of 4 amino acid mixtures, glucose, and a diet containing 40 g of protein were investigated. Amino acids given intravenously in a dose of 50 g/day. There were no differences between the groups in carbohydrate load (147 k J/kg BW), and with the adapted solutions (A, B, and C) enhanced plasma levels of methionine returned to normal in most instances. Physiological methionine and free tryptophan concentrations generally remained in the normal range. No constant alterations were observed in phenylalanine and tyrosine levels. The initially subnormal values for valine, leucine, and isoleucine could be elevated into the lower normal range. Solution D, composed for requirements of patients with intact liver function, caused excessively high values of methionine and free tryptophan, whereas the levels of phenylalanine and tyrosine were not increased, nor could correction of the levels of the branched chain amino acids be achieved by the solution. Glucose reduced methionine and aromatic amino acids in plasma but diminished valine and leucine as well. Nitrogen balances, calculated from the renal nitrogen excretion improved during the treatment with 2 of the solutions (A and B), but positive balances with the third solution (C) could be achieved only when 10 to 15 g protein was added to the diet. The amino acid solutions adapted to the metabolism in hepatic failure to a normalisation of pathological amino acid levels, to an acceleration of the EEG, and with one solution (A) to a positive nitrogen balance.