[Measurement and model-interpretation of new parameters of lung mechanics (author's transl)]

In 34 subjects (healthy and patients with obstructive and restrictive lung diseases) the components R and X of the respiratory impedance were measured in relation to the oscillatory frequency f by means of the forced oscillations technique. Using a frequency range from 5 to 30 Hz we found significant differences in these three groups of subjects for the frequency dependence of the R(f) and X(f) curves. A model-analysis showed that frequency dependence of R and X is mainly caused by the influence of the compliance of the central and upper airways. The magnitude of this influence is a function of the peripheral airway resistance.