Journal of Applied Physiology Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Appl Physiol 69: 553-561, 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 Tsuda, A.
Right arrow Articles by Fredberg, J. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Tsuda, A.
Right arrow Articles by Fredberg, J. J.

Journal of Applied Physiology, Vol 69, Issue 2 553-561, Copyright © 1990 by American Physiological Society

ARTICLES

Periodic flow at airway bifurcations. II. Flow partitioning

A. Tsuda, R. Kamm and J. J. Fredberg
Worcester Polytechnic Institute, Massachusetts 01609.

The distribution of flow among parallel pathways is believed to be determined by the balance of downstream mechanical loads or time constants. We studied the influence of upstream flow conditions and airway geometry vs. downstream mechanical impedances in determining flow partitioning at airway bifurcations. Each model consisted of a single rigid bifurcation with various branching angles and area ratios but having identical pathway impedances. Sinusoidal volumetric oscillations were applied at the parent duct with various frequencies and tidal volumes. Measuring the terminal pressures continuously, we calculated the flow distribution. When flow amplitude was small, flow partitioning was homogeneous and synchronous, as expected in a system possessing homogeneous pathway impedances and time constants. But when flow amplitude was large and frequency was high, appreciable heterogeneity and asynchrony of flow partitioning arose; during midinspiration the high-velocity flow stream preferentially favored the axial pathway. This effect vanished in the absence of a net area change at the bifurcation. For a given bifurcation geometry, these observations could be organized using only two nondimensional parameters, neither of which incorporated consideration of fluid friction. The description of temporal events required, in addition, a nondimensional time. Therefore these flow-dependent phenomena and their underlying mechanisms differ fundamentally from those described in classical impedance models. The complex pattern of nonuniform interregional behaviors apparent in whole lungs when tidal volume and frequency are large (Allen et al., J. Clin. Invest. 76: 620-629, 1985) is reiterated faithfully in models consisting of only two compartments with homogeneous time constants. As such, the behaviors observed in lungs would appear to be attributable in large part to fluid dynamic factors in central airways.


This article has been cited by other articles:


Home page
 ScienceHome page
D. Bramble and F. Jenkins Jr
Mammalian locomotor-respiratory integration: implications for diaphragmatic and pulmonary design
Science, October 8, 1993; 262(5131): 235 - 240.
[Abstract] [PDF]


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