Exploration of Fluid Dynamics in Perioperative Patients Using Bioimpedance Analysis

Introduction: Perioperative fluid restriction is advocated to reduce complications after major surgeries. Current methods of monitoring body fluids rely on indirect volume markers that may at times be inadequate. In our study, bioimpedance analysis (BIA) was used to explore fluid dynamics, in terms of intercompartmental shift, of perioperative patients undergoing operation for hepato-pancreato-biliary (HPB) diseases. Methods: A retrospective review was conducted, examining 36 patients surgically treated for HPB diseases between March 2010 and August 2012. Body fluid compartments were estimated via BIA at baseline (1 day prior to surgery), immediately after surgery, and on postoperative day 1, recording fluid balance during and after procedures. Patients were stratified by net fluid status as balanced (≤500 mL) or imbalanced (>550 mL) and outcomes of BIA compared. Results: Mean net fluid balance volumes in balanced (n = 16) and imbalanced (n = 20) patient subsets were 231.41 ± 155.44 and 1050.18 ± 548.77 mL, respectively. Total body water (TBW) (p = 0.091), extracellular water (ECW) (p = 0.125), ECW/TBW (p = 0.740), and intracellular water (ICW) (p = 0.173) did not fluctuate significantly in fluid-balanced patients. Although TBW (p = 0.069) in fluid-imbalanced patients did not change significantly (relative to baseline), ECW (p = 0.001), ECW/TBW (p = 0.019), and ICW (p = 0.012) showed significant postoperative increases. Conclusion: The exploration of fluid dynamics using BIA has shown importance of balanced fluid management during perioperative period. Increased ECW/TBW in fluid-imbalanced patients suggests possible causality for the development of ascites or fluid collections during postoperative period in patients undergoing HPB operations.