Michel Y. Jaffrin

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This paper reviews various bioimpedance methods permitting to measure non-invasively, extracellular, intracellular and total body water (TBW) and compares BIA methods based on empirical equations of the wrist-ankle resistance or impedance at 50 kHz, height and weight with BIS methods which rely on an electrical model of tissues and resistances measured at(More)
Extracellular (ECW) and intracellular (ICW) volumes were measured using both segmental and wrist-ankle (W-A) bioimpedance spectroscopy (5-1000 kHz) in 15 healthy subjects (7 men, 8 women). In the 1st protocol, the subject, after sitting for 30 min, laid supine for at least 30 min. In the second protocol, the subject, who had been supine for 1 hr, sat up in(More)
PURPOSE OF REVIEW To review various methods for measuring body composition by bioimpedance and their limitations, as well as available impedance meters, including body fat analyzers for home use. RECENT FINDINGS Bioimpedance spectroscopy, which requires multifrequency impedance meters, is preferable for fluid volume measurements, especially extracellular(More)
We propose a method for calculating directly total body water (TBW) volumes (V t) from whole body resistance extrapolated at infinite frequency (R ∞) using a XITRON 4200 impedance meter. Mean TBW resistivities for men and women were determined from measurements of R ∞ and fat-free mass (FFMd) measured by DXA in 58 healthy subjects assuming an average(More)
The purpose of this work was to study the factors determining aortic input impedance in hypertensive patients. Aortic input impedance (simultaneous measurements of aortic pressure and blood flow), mean (Wm) and pulsatile (Wp) powers and the Wp/Wm ratio were compared in normal subjects (n = 13) and hypertensive patients (n = 12) under basal conditions and(More)
A method for extrapolating the extracellular water (ECW) resistance from wrist–ankle resistance at 50 kHz (R 50) is proposed in this paper, in order to enable 50 kHz impedancemeters to use the BIS-Hanai equation for determination of ECW. Values of R 50 and the ECW resistance extrapolated at zero frequency R e were measured in a first group of 57 healthy(More)
The purpose of this work was to analyze, in human subjects, the shape of the aortic pressure wave from its forward and backward components calculated by use of Westerhof's model. Twenty-nine patients were studied: 11 normal subjects, 11 hypertensive patients and 7 patients with congestive heart failure. The following measurements and calculations were(More)
This study was aimed at the evaluation of aortic impedance in patients with congestive heart failure. Aortic impedance (simultaneous measurements of aortic pressure and blood flow), mean (Wm) and pulsatile (Wp) powers were compared in 11 normal subjects and in 12 patients with heart failure. Pulse wave velocity (C: modified Moëns-Korteweg equation,(More)