A comparison of two- and four-electrode techniques to characterize blood impedance for the frequency range of 100 Hz to 100 MHz.
Measurement setups that characterize the impedance of suspensions of blood over the wide frequency range of 100 Hz to 100 MHz are presented in this paper. The performance of the two- and four-electrode techniques have been compared and evaluated. By applying a combination of the two measurement techniques the best result is achieved when taking into account the main nonidealities, such as electrode polarization impedance and parasitic capacitances. It has been found that the conventional three-element model for the impedance of blood can be used for frequencies up to 1 MHz. For frequencies exceeding 1 MHz, an extended model is introduced where a constant phase angle element is used for modeling the cell membrane and a capacitor C(liq) is added for modeling the electrical capacitance of water in blood.
Chang
Zu-yao
ZY
Electronic Instrumentation Laboratory, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands. z.y.chang@tudelft.nl
Pop
Gheorghe M
GM
Meijer
Gerard M
GM
D001774:Blood Chemical Analysis / Q000295:instrumentation* / Q000379:methods; D001809:Blood Viscosity / Q000502:physiology*; D017097:Electric Impedance; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D010992:Plethysmography, Impedance / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity