Journal of Applied Physiology, Vol 48, Issue 1 45-53, Copyright © 1980 by American Physiological Society
Frequency dependence of dynamic compliance analyzed from one cycle of breathing
T. Sasaki, S. Suzuki, M. Sugiyama and T. Takishima
An analytical method for testing frequency dependence of dynamic compliance
(Cdyn) from a Fourier-series analysis of flow and transpulmonary pressure
in a single cycle of breathing was described and compared to the
conventional method in an electrical model, in excised dog lobes and in
human subjects. In the electrical model, the frequency dependence of Cdyn
in the Fourier method corresponded exactly with the theoretical frequency
dependence of Cdyn. A frequency dependence of Cdyn was evaluated by a ratio
of Cdyn at 1 Hz to Cdyn at zero frequency, C1Hz/CoHz, from the regression
line between Cdyn and the frequency in excised dog lobes and human
subjects. In healthy nonsmokers, C1Hz/CoHz was significantly smaller in the
Fourier method than in the conventional method. The discrepancy of
frequency dependence of Cdyn between the two methods was thought to be
possibly due to the effects of the nonsinusoidal breathing pattern on the
conventional method, and due to the effects of a volume-dependent
compliance on the Fourier method.
