|
|
||||||||
Journal of Applied Physiology, Vol 70, Issue 3 1051-1058, Copyright © 1991 by American Physiological Society
ARTICLES |
A. C. Jackson and K. R. Lutchen
Department of Biomedical Engineering, Boston University, Massachusetts 02215.
The lumped six-element model of the respiratory system proposed by DuBois et al. (J. Appl. Physiol. 8: 587-594, 1956) has often been used to analyze respiratory system impedance (Zrs) data. This model predicts a resonance (relative minimum in Zrs) at fr between 6 and 10 Hz and an antiresonance (relative maximum in Zrs) at far at higher frequencies (greater than 64 Hz). The far is due to the lumped tissue inertance (Iti) and the alveolar gas compression compliance (Cg). An fr and far have been recently reported in humans, but the far was shown to be not related to Iti and Cg, but instead it is the first acoustic antiresonance of the airways due to their axial dimensions). Zrs data to frequencies high enough to include the far have not been reported in dogs. In this study, we measured Zrs in dogs for frequencies between 5 and 320 Hz and found an fr at 7.5 +/- 1.6 Hz and two far at 97 +/- 13 and 231 +/- 27 Hz (far,1 and far,2, respectively). When breathing 80% He-20% O2, the fr shifted to 14 +/- 2 Hz, far,1 did not change (98 +/- 9 Hz), and far,2 increased to greater than 320 Hz. The behavior of fr and far,1 is consistent with the structure-function implied by the six-element model. However, the presence of an far,2 is not consistent with this model, because it is the airway acoustic antiresonance not represented in the model. These results indicate that, for frequencies that include the fr and far,1, the six-element model can be used to analyze Zrs data and reliable estimates of the model's parameters can be extracted by fitting the model to the data. However, more complex models must be used to analyze Zrs data that include far,2.
This article has been cited by other articles:
![]() |
C. Thamrin, P. D. Sly, and Z. Hantos Broadband frequency dependence of respiratory impedance in rats J Appl Physiol, October 1, 2005; 99(4): 1364 - 1371. [Abstract] [Full Text] [PDF] |
||||
![]() |
U. FREY, M. SILVERMAN, R. KRAEMER, and A. C. JACKSON High-frequency Respiratory Impedance Measured by Forced-Oscillation Technique in Infants Am. J. Respir. Crit. Care Med., August 1, 1998; 158(2): 363 - 370. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. F. Sobh, C. M. Lilly, J. M. Drazen, and A. C. Jackson Respiratory transfer impedance between 8 and 384 Hz in guinea pigs before and after bronchial challenge J Appl Physiol, January 1, 1997; 82(1): 172 - 181. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |