Symposium on nutritional requirements of the surgical patient. 1. Nutrition and body composition.

Body composition measurements were determined by a multiple isotope dilution technique to assess nutritional status of patients and to determine the efficacy of nutritional support. The body composition of 75 patients with severe malnutrition was characterized by a contracted body cell mass with a relatively expanded extracellular mass. An elective operation of moderate severity resulted in a 14% decrease in the body cell mass while the extracellular mass increased by 10%. The 4% postoperative decrease in body weight did not accurately reflect the change in the body cell mass. The efficacy of total parenteral nutrition (TPN) with lipid as the major caloric source was compared with TPN with hypertonic dextrose. With lipid a daily infusion of 44.2 Cal/kg (185 kJ/kg) was required to maintain the body cell mass while with the solution containing hypertonic dextrose 34.7 Cal/kg (155 kJ/kg) was required--a 27% difference. Total parenteral nutrition with hypertonic dextrose is therefore more efficacious than TPN with lipid as the major caloric source.