Use of Bioimpedance Spectroscopy for Postoperative Fluid Management in Patients Undergoing Cardiac Surgery with Cardiopulmonary Bypass

Abstract

ObjectiveTo assess whether bioimpedance spectroscopy analysis (BIA) can be used as a potential tool to guide postoperative fluid management in patients who undergo cardiac surgery. DesignAn observational study. SettingA single, tertiary hospital. ParticipantsPatients who underwent cardiac surgery with cardiopulmonary bypass between June to November 2023 who were able to undergo BIA measurements. InterventionsNone. Measurements and Main ResultsCorrelations between BIA measurements of extracellular fluid (ECF) and total body water (TBW) volumes and daily changes in weight and 24-hour net intake and output (I/O) of fluids were assessed. Correlations between pre-discharge ECF volume as a percentage of TBW volume (ECF%TBW) and pre-discharge Pro-BNP (Pro-BNP) levels and readmissions were analyzed. Changes in daily ECF volume significantly correlated with daily weight changes (p<0.01) and 24-hr I/O (p<0.01). TBW volume significantly correlated with daily weight changes (p<0.01) and with 24-hr I/O (p=0.04). Daily weight changes did not correlate with 24-hr I/O (p=0.06). The patients with pre-discharge ECF%TBW(%) greater than or equal to 51 had significantly higher pre-discharge Pro-BNP than those with ECF%TBW(%) less than 51 (p<0.01). Patients who had heart failure revisits or admissions after discharge had a higher pre-discharge ECF%TBW(%) on index admission compared to patients that did not have heart failure readmissions (p=0.01). ConclusionsUtilization of BIA measurements in postoperative cardiac surgery patients may be a valuable tool to quantitatively determine fluid status to help guide fluid management in this patient population. Further studies validating the use of BIA for postoperative care in this population are warranted.