Journal of Applied Physiology AJP: Advances in Physiology Education
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Appl Physiol 69: 945-955, 1990;
8750-7587/90 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Meyer, M.
Right arrow Articles by Piiper, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Meyer, M.
Right arrow Articles by Piiper, J.

Journal of Applied Physiology, Vol 69, Issue 3 945-955, Copyright © 1990 by American Physiological Society

ARTICLES

Cardiogenic oscillations in He and SF6 expirograms during airway and venous loading

M. Meyer, S. M. Lewis, M. Mohr, H. Schulz, K. D. Schuster and J. Piiper
Department of Physiology, Max Planck Institute for Experimental Medicine, Gottingen, Federal Republic of Germany.

Cardiogenic oscillations in the expired partial pressure profiles of two inert gases (He and SF6) were monitored in seven anesthetized paralyzed mechanically ventilated dogs. He and SF6 were administered either intravenously by a membrane oxygenator and partial arteriovenous bypass [venous loading (VL)] or by washin into lung gas [airway loading (AL)]. The single-breath expirograms obtained during constant-flow expiration after inspiration of test gas-free air displayed distinct and regular cardiogenic oscillations. The relative oscillation amplitude (ROA), calculated as oscillation amplitude divided by mixed expired-inspired partial pressure difference, was in the range of 1-8%. The ROA for both He and SF6 was approximately 4.2 times higher in VL than in AL, which indicated that among lung units that emptied sequentially in the cardiac cycle, the effects of alveolar ventilation-perfusion (VA/Q) inequality were more pronounced than those of alveolar ventilation-alveolar volume (VA/VA) inequality. In AL, He and SF6 oscillations were 180 degrees out of phase compared with CO2 and O2 oscillations and with He and SF6 oscillations in VL, which suggests that regions with low VA/VA had high VA/Q and very low Q/VA. The ROA was practically unaffected by breath holding in both AL and VL, which indicates that there was little diffusive or convective (cardiogenic) mixing between the lung units that were responsible for cardiogenic oscillations. The ROA was consistently higher for He than for SF6, and the He-to-SF6 ratio was independent of route of test gas loading, averaging 1.6 in both AL and VL. This result may be explained by laminar Taylor dispersion, whereby oscillations generated in peripheral lung regions are dissipated in inverse proportion to diffusion coefficient during transit through the proximal (larger) airways.


This article has been cited by other articles:


Home page
 J. Appl. Physiol.Home page
Y. Verbandt, M. Wantier, G. K. Prisk, and M. Paiva
Ventilation-perfusion matching in long-term microgravity
J Appl Physiol, December 1, 2000; 89(6): 2407 - 2412.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
A.-M. Lauzon, A. R. Elliott, M. Paiva, J. B. West, and G. K. Prisk
Cardiogenic oscillation phase relationships during single-breath tests performed in microgravity
J Appl Physiol, February 1, 1998; 84(2): 661 - 668.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online