Active metabolic expenditure of gastroenterological surgical patients receiving intravenous nutrition.

The active metabolic expenditure of 30 gastroenterological surgical patients was measured by performing an energy balance study over 14 days of intravenous nutrition. The mean value of active metabolic expenditure in preoperative patients (559 +/- 384 kcal/day) was significantly higher (p less than 0.02) than postoperative patients (245 +/- 325 kcal/day) but there was wide individual variation within both groups. Combinations of these results with values of resting metabolic expenditure obtained in the same patients suggest that very few uncomplicated surgical patients will ever require more than 2000 kcal/day to achieve a positive energy balance.