Bioelectrical impedance analysis to assess changes in body water compartments after digestive surgery

BACKGROUND/AIMS: Accurate monitoring of fluid balance in patients after surgery is a difficult task. Bioelectrical impedance analysis (BIA) is a safe and noninvasive method to measure extracellular water (ECW) and intracellular water (ICW) by passing a weak alternating current through the body. The purpose of the present study was to evaluate changes in body water compartments after gastroenterological surgery by BIA in relation to patient age, type of operation, postoperative complications and systemic inflammatory response syndrome (SIRS). METHODOLOGY: Ninety-four patients undergoing digestive surgery in our department laparoscopic cholecystectomy (n=9), gastrectomy (n= 23), colectomy (n=26), hepatectomy (n=29), pancreatoduodenectomy (n=4) and esophagectomy (n=3)] were enrolled in the study. Body fluids were measured by bioelectrical impedance analysis before and after surgery (one hour after operation and on postoperative days 1, 3, 7 and 14). RESULTS: Total body water (TBW) and ICW in all groups were significantly lower than preoperative values on day 14. Day 14 ECW in patients less than 70 years or age without postoperative SIRS or complications was significantly lower than the preoperative value. In contrast, ECW was not significantly different from the preoperative value in patients older than age 70 with postoperative SIRS. Additionally, ECW on day 14 was significantly higher than the preoperative value in patients with postoperative complications. When types of surgery were taken into consideration, day 14 TBW was significantly lower than preoperative value only in patients with gastrectomy and hepatectomy. CONCLUSIONS: Development of postoperative SIRS and complications resulted in an increase of ECW above its preoperative value. BIA is useful for detecting small changes in body composition following gastroenterological surgery, and provides a means for monitoring perioperative water balance.