Factors affecting the metabolic expenditure of surgical patients

Abstract

The estimation of resting metabolic expenditure in surgical patients by indirect calorimetry is possible using Noyon's (1937) diaferometer. The limitations of this instrument are described. Utilization of carbohydrate appears to be diminished following operation. Fat becomes the main calorie source and there is an increased catabolism of protein. Patients who are undergoing uncomplicated, elective surgery of moderate severity and who are given a low calorie intake show no change in total metabolic expenditure after operation. The administration of parenteral nutrients reverses the negative balances of nitrogen and of energy and increases resting metabolic expenditure.