The Effect of Body Composition and Age on the Metabolic Response to Stress after Colorectal Surgery

ABSTRACT

PURPOSE: We wanted to evaluate the effect of body composition and age on the metabolic responses before and after elective colorectal resection. METHODS: We studied 20 active, healthy patients who underwent elective colorectal surgery. Their body composition was measured by using a Bioelectrical Impedance Analyzer. The O2 and CO2 consumption (VO2 and VCO2), respiratory quotient (RQ) and resting energy expenditure (REE) were measured by Indirect Calorimetry with using a Ventilated Hood System. RESULTS: The median age was 55 year (range 35~70 year). The serum glucose, cortisol, insulin, C-reactive protein, cathecholamine and total body water (TBW), postoperative mean VO2, VCO2 and REE were all independent of patient age. The REE increased 9+/-4.3% after operation, but this increase was not related to age. The TBW was strongly related with the preoperative VO2 and VCO2, and the preoperative REE (r2=0.42~0.57, P<0.001). The postoperative VO2, VCO2 and REE were dependent on the TBW. The preoperative REE was dependent on the age, gender, preoperative TBW and body muscle mass (r2=0.526, P<0.000). The postoperative REE was dependent on the TBW and it was strongly related with the preoperative value (r2=0.796, P< 0.000). The postoperative day change of the REE was dependent on the postoperative day change of the TBW (r2=0.700, P=0.04). CONCLUSION: The TBW was not related to age. The TBW was the most valuable index to predict the change of the postoperative REE. Therefore, the preoperative TBW may be considered as the meaningful indicator to predict the change of the postoperative REE.