Bioelectrical impedance analysis as an assessment of diuresis in congestive heart failure

OBJECTIVE: To compare changes in bioimpedance parameters and calculated total body water (TBW) with conventional measurements used to assess the efficacy of diuretic therapy in the treatment of heart failure. SETTING: A Veterans Affairs tertiary care, teaching hospital. SUBJECTS: Twelve patients with New York Heart Association (NYHA) class III congestive heart failure (CHF). DESIGN: Prospective, consecutive sample, cohort, open label. INTERVENTIONS: Parenterally administered furosemide; clinically dictated, outcome-oriented, adjunctive therapy of CHF. OUTCOMES: Bioelectrical impedance analysis (BIA) parameters, measured volume of diuresis and changes in body weight, defined clinical endpoints (NYHA criteria). RESULTS: Three days of diuretic therapy with furosemide (oral and/or intravenous) for CHF was associated with a measured weight loss of 4.1 +/- 0.6 kg and statistically significant increases in resistance and reactance of 20.8% +/- 2.7% and 22.7% +/- 6.1%, respectively (p < 0.005). Calculated TBW using BIA parameters and standard equations decreased on average by 6.1 +/- 0.6 L or 11.2% +/- 1.1% (p < 0.001). A significant inverse correlation was observed between change in measured body weight and total body reactance (p = 0.02). CONCLUSIONS: Single-frequency BIA appears to have limited clinical usefulness as a method of assessing diuretic therapy in the management of CHF. Its greatest usefulness appears to lie in the assessment of serial changes in individual patients and patient populations that are physiologically or metabolically homogeneous. Further studies are needed to establish the validity of BIA in patients with decompensated CHF.