. Author manuscript; available in PMC: 2011 Mar 16.

Published in final edited form as: Am Heart J. 2008 Dec 16;157(3):402–411. doi: 10.1016/j.ahj.2008.10.016

Table IV.

Selected major impedance comparison studies of fluid measurement

Study setting	Eligibility criteria and patient group	Sample size	Method	R	Results and conclusions
Hospital ICU⁵⁰	NYHA class III-IV, implanted pacers	17	PCWP vs ICG (implant)	−0.61	14% average decrease in impedance over 2 wk inversely correlates to increase in PCWP, impedance, and PCWP restored to baseline after intravenous therapy
University hospital¹⁵	Coronary disease, valvular disease, hypertension, pulmonary edema, control group without edema	60	CX-ray and PE vs ICG (external)	NR	15% decrease in impedance from baseline 1 h before clinical symptoms, 22% greater decrease than control group inversely correlates to crepitation rales, impedance returned to baseline after edema resolution
Teaching hospital¹⁶	Suspected heart failure, dyspnea (n = 131)	131	CX-ray vs ICG (external)	NR	Lower impedance in cardiomegaly (25%) and pulmonary edema (26%) compared to normals, all groups with same average baseline impedance, no difference between cardiomegaly and edema

PCWP, Pulmonary capillary wedge pressure; CX-ray, chest X-ray; PE, physical exam; NR, not reported.