Influence of water immersion on the airway impedance measured by forced oscillation technique

Abstract

IntroductionFew studies have examined the influence of different water depths on the airway impedance measured by forced oscillation technique in healthy adults. MethodsEleven healthy men (23.2 ± 1.5 years old) participated in this study. We measured the respiratory impedance assessed with the resistance at frequency of 5 Hz and 20 Hz, the reactance at frequency of 5 Hz, and frequency of resonance. To compare the influence of water depths, we carried out one dryland (DL) and two water level conditions: clavicle level (CL) and xiphoid appendix level (XA). ResultsThe respiratory resistance at frequency of 5 Hz was higher in CL and XA than DL, and at 20 Hz was significantly higher in CL than DL. The respiratory reactance at 5 Hz was lower in CL and XA than DL, and frequency of resonance was higher in CL and XA than DL. ConclusionThese results suggested that water immersion above xiphoid appendix level increase airway resistance.