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 ® (5–1000 kHz) 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 100 kHz, TBW differences between the FFI and Xitron were not significant, 0.17 ± 2.17 L for men ( P = 0.694) and 0.04 ± 1.88 L 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 ± 2.27 L for men ( P = 0.237) and −0.72 ± 2.37 L 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.