|
|
||||||||
Journal of Applied Physiology, Vol 48, Issue 4 648-656, Copyright © 1980 by American Physiological Society
ARTICLES |
D. J. Cotton and B. L. Graham
Recent studies have shown that diffusing capacities measured at multiple intervals during a single exhalation [DLCO(exhaled)] remained constant with lung volume in normal subjects, but decreased with decreasing lung volume in patients who may have had diffusion nonuniformity. We have examined the theoretical basis of these results by determining what factors affected DLCO(exhaled) in a computerized lung model in which diffusion in each compartment remained constant with lung volume. DLCO(exhaled) decreased with decreasing lung volume when a small lung region lacked diffusion. However, the change in DLCO(exhaled) with lung volume was also affected by nonuniform ventilation and these effects could not be eliminated by correcting the carbon monoxide decay and the simultaneous decay of helium. DLCO(exhaled) values were also influenced by the exhaled flow rate in the presence of nonuniform ventilation and/or nonuniform diffusion. However, prolonging the period of breath holding prior to exhalation reduced DLCO(exhaled) values at all lung volumes when non-uniform diffusion was simulated, but did not affect DLCO(exhaled) when only nonuniform ventilation was simulated.
This article has been cited by other articles:
![]() |
S. Verbanck, D. Schuermans, S. Van Malderen, W. Vincken, and B. Thompson The effect of conductive ventilation heterogeneity on diffusing capacity measurement J Appl Physiol, April 1, 2008; 104(4): 1094 - 1100. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. J. M. Horstman, F. W. Mertens, D. Schotborg, H. C. Hoogsteden, and H. Stam Comparison of Total-Breath and Single-Breath Diffusing Capacity in Healthy Volunteers and COPD Patients Chest, January 1, 2007; 131(1): 237 - 244. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y.-C. T. Huang, S. R. O'Brien, and N. R. MacIntyre Intrabreath Diffusing Capacity of the Lung in Healthy Individuals at Rest and During Exercise* Chest, July 1, 2002; 122(1): 177 - 185. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. B. Perillo, R. W. Hyde, A. J. Olszowka, A. P. Pietropaoli, L. M. Frasier, A. Torres, P. T. Perkins, R. E. Forster II, M. J. Utell, and M. W. Frampton Chemiluminescent measurements of nitric oxide pulmonary diffusing capacity and alveolar production in humans J Appl Physiol, November 1, 2001; 91(5): 1931 - 1940. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |