Measurements of total body water with a foot-to-foot impedancemeter

Abstract 

The objective was to set-up a method for measuring total body water volumes (TBW) using a Tefal foot-to-foot impedancemeter (FFI) by comparison with a multifrequency medical impedancemeter and to validate this method against deuterium dilution data. The investigation was carried out in 57 Caucasian adult subjects. Impedancemeters were a Tefal Bodymaster Vision^® (foot-to-foot) featuring a square wave signal and a Xitron Hydra 4200^® (5–1000kHz) using BIS method. TBW was measured by the Xitron using a new method that we have developed which applies the BIS method directly to extra and intracellular fluids combined. Although the high frequency impedance of the FFI (R_hf) was higher than the Xitron infinite frequency resistance and corresponded to a frequency around 100kHz, TBW differences between the FFI and Xitron were not significant, 0.17±2.17L for men (P=0.694) and 0.04±1.88L for women (P=0.902). Then, our method was tested on another Caucasian population in which R_hf had been measured with the same FFI, together with TBW measurements by deuterium dilution. TBW differences between the FFI and dilution were −0.38±2.27L for men (P=0.237) and −0.72±2.37L for women (P=0.06).

Our method permits, at least in a Caucasian healthy population, to measure TBW using this FFI with the same accuracy as a whole body multifrequency medical impedancemeter, and the measurement, made in upright position, is much quicker.

Abbreviations: BIS, bioimpedance spectroscopy, ECW (ICW), extra (intra) cellular volume, FFI, foot-to-foot impedancemeter, FFM, fat-free-mass, TBW, total body water volume

Keywords: Total body water, Bioimpedance spectroscopy, Foot-to-foot impedancemetry