Amino Acids and Respiration

Abstract

Malnutrition frequently accompanies respiratory failure and may play an important role in the pathophysiology of the disease. Parenteral nutrition containing glucose and amino acids may stimulate respiration. To ascertain the effect of these solutions on respiration, 8 normal subjects received an infusion of 5% dextrose (100 ml/h) for 7 days followed by an infusion of 3.5% amino acids (125 ml/h) for 24 h. Minute ventilation (.ovrhdot.VE), tidal volume, mean inspiratory flow (VT/Tl), O2 consumption and CO2 production were significantly depressed after 7 days of 5% dextrose infusion. Ventilation and metabolic rate increased within 4 h after initiation of the amino acid infusion and returned to normal 24 h after the infusion. The effect of the amino acids on (.ovrhdot.VE) is secondary to an increase in (VT/Tl), which is an indicator of neuromuscular ventilatory drive. Within 4 h amino acids will restore depressed metabolic rate, minute ventilation and ventilatory drive after prolonged infusion of 5% dextrose.