The effects of standard and branched chain amino acid enriched solutions on thermogenesis and energy expenditure in unconscious intensive care patients

Background Et Aims: This study aims to compare the effects of standard and branched chain amino acid enriched solutions on thermogenesis and energy expenditure in unconscious and mechanically ventilated intensive care patients. Designs: The study was carried out at multidisciplinary intensive care unit. Twenty unconscious and mechanically ventilated patients (18-65 years, of age) were included in the study. Patients were hemodynamically stable and all received continuous enteral nutrition. Energy expenditure was calculated using the Harris-Benedict Equation for all of the patients. Patients were randomly assigned to receive a 4h infusion of 0.4g/kg protein as amino acid solution. Group I (n = 10) received standard amino acid solution and group 11 (n = 10) received branched chain amino acid enriched solution. Energy expenditure, oxygen consumption and carbon dioxide production were measured by indirect calorimetric method every 30min during the 4 h infusion period and 3 h thereafter. Rectal temperature was recorded concomitantly with the metabolic measurements throughout the study. Results: There was a statistically significant increase in body temperature during the infusion of amino acid solution between 30 and 210 min in group I and between 30 and 120 min in group 11 (P<0.05). We observed a significant increase in energy expenditure at 30, 150, 180 and 210 min in group I and at 30-240 min in group 11 (P<0.05). There were no differences between the two groups in terms of thermogenesis or energy expenditure values during the study (P>0.05). Conclusion: Thermogenesis and energy expenditure values were increased during the parenteral infusion of both standard amino acid and branched chain amino acid enriched solutions in unconscious intensive care patients without any significance in between. (C) 2003 Elsevier Ltd. All rights reserved.