WITHIN-BREATH MEASUREMENT OF RESPIRATORY IMPEDANCE

The measurement of the complex respiratory impedance at a high tempora l resolution is described. The measurement of impedance is correlated with the breathing cycle using electrical transthoracic impedance. Thi s allows the determination of the complex impedance at any fixed point in the respiratory cycle, which results in lower variability in the m easured data when compared to the original device. The respiratory imp edance in normal subjects fluctuates during the breathing cycle and ha s two maxima during a single breath, which occur at peak inspiratory a nd expiratory flow. In addition, the measurement of impedance at a hig h temporal resolution enables the observation of novel features in the impedance which appear to be associated with certain respiratory diso rders.