title: Detection of respiratory waveforms using non-contact electrodes during bathing.
abstract: The aim of this study is to develop a method for measuring the respiratory waveform using non-contact electrodes during bathing. To determine the most appropriate electrode arrangement, we modeled a composite system consisting of a body submerged in bath water. We calculated the frequency dependence of the impedance amplitude using a three-dimensional finite difference method (3D-FDM). The simulation results showed that an increase in chest size due to inspiration caused a decrease in the impedance amplitude in the frequency range of 0.1 Hz to 1 MHz. Next, bioelectric impedance (BEI) was measured in the frequency range of 4 kHz to 4 MHz at the maximum-end-expiration and maximum-end-inspiration stages. BEI results were consistent with those obtained from the model simulations. We found that 1 MHz was the appropriate frequency for measuring the respiratory waveform, and the time dependence of the impedance amplitude was measured at 1 MHz. The impedance amplitude agreed well with the respiratory waveform obtained from rubber strain gauge plethysmography, which was used as a reference.
authors.affiliation: Division of Bio-Information Engineering, Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan. kazukin@eng.u-toyama.ac.jp
authors.forename: Kazuki
authors.initials: K
authors.lastname: Nakajima
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Sekine
authors.forename: Katsuya
authors.initials: K
authors.lastname: Yamazaki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tampo
authors.forename: Yuuichirou
authors.initials: Y
authors.lastname: Omote
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fukunaga
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Yagi
authors.forename: Kyoji
authors.initials: K
authors.lastname: Ishizu
authors.forename: Masanori
authors.initials: M
authors.lastname: Nakajima
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Tobe
authors.forename: Masashi
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Sasaki
mesh_terms: D001494:Baths / Q000295:instrumentation*; D003198:Computer Simulation; D017076:Computer-Aided Design; D017097:Electric Impedance; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007101:Immersion / Q000503:physiopathology*; D008954:Models, Biological; D010992:Plethysmography, Impedance / Q000295:instrumentation*; D015203:Reproducibility of Results; D012129:Respiratory Function Tests / Q000295:instrumentation*; D015656:Respiratory Mechanics / Q000502:physiology*; D012680:Sensitivity and Specificity