|
|
||||||||
Journal of Applied Physiology, Vol 79, Issue 3 929-940, Copyright © 1995 by American Physiological Society
ARTICLES |
S. C. George, J. E. Souders, A. L. Babb and M. P. Hlastala
Department of Chemical Engineering, University of Washington, Seattle 98195-6540, USA.
The functional dependence between tracheal gas exchange and tracheal blood flow has been previously reported using six inert gases (sulfur hexafluoride, ethane, cyclopropane, halothane, ether, and acetone) in a unidirectionally ventilated (1 ml/s) canine trachea (J. E. Souders, S. C. George, N. L. Polissar, E. R. Swenson, and M. P. Hlastala. J. Appl. Physiol. 79: 918-928, 1995). To understand the relative contribution of perfusion-, diffusion- and ventilation-related resistances to airway gas exchange, a dynamic model of the bronchial circulation has been developed and added to the existing structure of a previously described model (S. C. George, A. L. Babb, and M. P. Hlastala. J. Appl. Physiol. 75: 2439-2449, 1993). The diffusing capacity of the trachea (in ml gas.s-1.atm-1) was used to optimize the fit of the model to the experimental data. The experimental diffusing capacities as predicted by the model in a 10-cm length of trachea are as follows: sulfur hexafluoride, 0.000055; ethane, 0.00070; cyclopropane, 0.0046; halothane, 0.029; ether, 0.10; and acetone, 1.0. The diffusing capacities are reduced relative to an estimated diffusing capacity. The ratio of experimental to estimated diffusing capacity ranges from 4 to 23%. The model predicts that over the ventilation-to-tracheal blood flow range (10-700) attained experimentally, tracheal gas exchange is limited primarily by perfusion- and diffusion-related resistances. However, the contribution of the ventilation-related resistance increases with increasing gas solubility and cannot be neglected in the case of acetone. The increased role of diffusion in tracheal gas exchange contrasts with perfusion-limited alveolar exchange and is due primarily to the increased thickness of the bronchial mucosa.
This article has been cited by other articles:
![]() |
H. Schulz, A. Schulz, G. Eder, and J. Heyder Labeled carbon dioxide (C18O2): an indicator gas for phase II in expirograms J Appl Physiol, November 1, 2004; 97(5): 1755 - 1762. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. A. Altemeier, H. T. Robertson, and R. W. Glenny Pulmonary gas-exchange analysis by using simultaneous deposition of aerosolized and injected microspheres J Appl Physiol, December 1, 1998; 85(6): 2344 - 2351. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. M. Tsoukias and S. C. George A two-compartment model of pulmonary nitric oxide exchange dynamics J Appl Physiol, August 1, 1998; 85(2): 653 - 666. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. D. Bui, D. Dabdub, and S. C. George Modeling bronchial circulation with application to soluble gas exchange: description and sensitivity analysis J Appl Physiol, June 1, 1998; 84(6): 2070 - 2088. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. P. Hlastala The alcohol breath test---a review J Appl Physiol, February 1, 1998; 84(2): 401 - 408. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |