Perioperative trends in neck and leg fluid volume in surgical patients: a prospective observational proof-of-concept study.

Purpose: The severity of obstructive sleep apnea (OSA) may increase postoperatively. The changes in segmental fluid volume, especially neck fluid volume, may be related to increasing airway collapsibility and thus worsening of OSA in the postoperative period. Our objective was to evaluate the feasibility of performing bioelectrical impedance analysis (BIA) and to describe the trend and predictors of changes in segmental fluid volumes in patients receiving general anesthesia for noncardiac surgery.