Sensitivity of multiple frequency bioelectrical impedance analysis to changes in ion status.

摘要: Bioelectrical impedance analysis has found extensive application as a simple non-invasive method for the assessment of body fluid volumes. The measured is, however, not only related to volume but also its inherent resistivity. primary determinant resistivities fluids is concentration ions. aim this study was investigate sensitivity bioelectrical bodily ion status. Whole over range frequencies (4-1012 kHz) rats during infusion various concentrations saline into concomitant with measurement total and intracellular water by tracer dilution techniques. Extracellular resistance (R0), (Ri) at characteristic frequency (Zc) were calculated. R0 Zc used predict extracellular respectively using previously published formulae. results showed that whilst decreased proportionately amount NaCl infused, Ri increased slightly. Impedances end predicted increases in TBW ECW approximately 4-6% despite increase less than 0.5% due infused. These data are discussed relation assumption constant resistivity prediction volumes from data.