Journal of Applied Physiology, Vol 58, Issue 4 1331-1339, Copyright © 1985 by American Physiological Society
Simulation of gas transport due to cardiogenic oscillations
A. S. Slutsky, M. C. Khoo and R. Brown
We simulated gas transport due to cardiogenic oscillations (CO) using a
model developed to quantify the gas mixing due to high-frequency
ventilation (16). The basic components of the model are 1) gas mixing by
augmented transport, 2) symmetrical lung morphometry, and 3) a Lagrangian
(moving) reference frame. The theoretical predictions of the model are in
general agreement with published experimental studies that have examined
the effect of CO on the nitrogen concentration obtained by intrapulmonary
gas sampling and the effect of CO on regional and total anatomical dead
space. Further, the model predicts that augmentation of gas transport due
to CO is less, nearer to the alveolar regions of the lung, and that the
effect of CO during normal tidal breathing is negligible, but that CO may
contribute up to approximately 10% of the alveolar ventilation in patients
with severe hypoventilation. The agreement between experimental and
theoretical results suggests that it may not be necessary to invoke gas
transport mechanisms specific to an asymmetrical bronchial tree to explain
the major proportion of gas transport due to CO.
