Measuring respirational parameters with a wearable bioimpedance device

Abstract

This paper studies the validity of electrical impedance pneumography (EIP) in measuring respiration rate and minute volume during physical exercise. We have developed a wearable wireless prototype device that was employed to measure changes in bioimpedance in the thorax area. A commercial spirometer was used as a reference. An ergometer with gradually increasing load was used for inducing different rates and depths of breathing in test persons. Estimate of the respiration parameters from the recorded impedance signal was produced by post measurement computer algorithm. Five of seven measurements show occasionally an abnormal breathing waveform in the bioimpedance signal, which significantly degrades the accuracy of the ventilation and respiration rate values estimated. The values derived from the two undistorted signals agree better with the values obtained from the spirometric system. Further investigation on the discovered distortion is needed. © Springer-Verlag 2007.