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Oscillation mechanics of the human lung periphery in asthma

Kaminsky, DA; Irvin, CG; Lundblad, Lennart LU ; Moriya, HT; Lang, S; Allen, J; Viola, T; Lynn, M and Bates, JHT (2004) In Journal of Applied Physiology 97(5). p.1849-1858
Abstract
To more precisely measure the mechanical properties of the lung periphery in asthma, we have developed a forced oscillation technique that applies a broad-band flow signal through a wedged bronchoscope. We interpreted the data from four healthy and eight mildly asthmatic subjects in terms of an anatomically accurate computer model of the wedged segment. There was substantial overlap in impedance between the two groups, with resistance ( R) showing minimal frequency dependence and elastance (E) showing positive and negative frequency dependence across subjects. After direct instillation of methacholine, R rose in both groups, but compared with healthy subjects, the asthmatic subjects displayed upward, parallel shifts in their dose-response... (More)
To more precisely measure the mechanical properties of the lung periphery in asthma, we have developed a forced oscillation technique that applies a broad-band flow signal through a wedged bronchoscope. We interpreted the data from four healthy and eight mildly asthmatic subjects in terms of an anatomically accurate computer model of the wedged segment. There was substantial overlap in impedance between the two groups, with resistance ( R) showing minimal frequency dependence and elastance (E) showing positive and negative frequency dependence across subjects. After direct instillation of methacholine, R rose in both groups, but compared with healthy subjects, the asthmatic subjects displayed upward, parallel shifts in their dose-response curves. The baseline frequency-response patterns of E were enhanced after methacholine. Frequency dependencies of R and E were well reproduced in two normal subjects by a computational model that employed rigid airways connected to constant-phase tissue units but were better reproduced in the other two normal and three asthmatic subjects when the model employed heterogeneous, peripheral airway narrowing and compliant airways. To capture the frequency dependencies of R and E in the remaining five asthmatic subjects, the model was modified by increasing airway wall stiffness. These results indicate that the lung periphery of mildly asthmatic subjects is not well distinguished from that of healthy subjects by measurement of mechanical impedance at baseline, but group differences are seen after challenge with methacholine. Modeling of the response suggests that variable contributions of airway narrowing and wall compliance are operative in determining overall mechanical impedance of the lung periphery in humans with asthma, likely reflecting the functional consequences of airway inflammation and remodeling. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
forced oscillation technique, impedance, airway remodeling
in
Journal of Applied Physiology
volume
97
issue
5
pages
1849 - 1858
publisher
American Physiological Society
external identifiers
  • wos:000224361700040
  • pmid:15220299
  • scopus:7044270909
ISSN
1522-1601
DOI
10.1152/japplphysiol.00300.2004
language
English
LU publication?
yes
id
559d3a4c-66a1-463b-8d50-76cc6a34285e (old id 265379)
date added to LUP
2007-10-23 15:35:41
date last changed
2017-08-27 04:02:37
@article{559d3a4c-66a1-463b-8d50-76cc6a34285e,
  abstract     = {To more precisely measure the mechanical properties of the lung periphery in asthma, we have developed a forced oscillation technique that applies a broad-band flow signal through a wedged bronchoscope. We interpreted the data from four healthy and eight mildly asthmatic subjects in terms of an anatomically accurate computer model of the wedged segment. There was substantial overlap in impedance between the two groups, with resistance ( R) showing minimal frequency dependence and elastance (E) showing positive and negative frequency dependence across subjects. After direct instillation of methacholine, R rose in both groups, but compared with healthy subjects, the asthmatic subjects displayed upward, parallel shifts in their dose-response curves. The baseline frequency-response patterns of E were enhanced after methacholine. Frequency dependencies of R and E were well reproduced in two normal subjects by a computational model that employed rigid airways connected to constant-phase tissue units but were better reproduced in the other two normal and three asthmatic subjects when the model employed heterogeneous, peripheral airway narrowing and compliant airways. To capture the frequency dependencies of R and E in the remaining five asthmatic subjects, the model was modified by increasing airway wall stiffness. These results indicate that the lung periphery of mildly asthmatic subjects is not well distinguished from that of healthy subjects by measurement of mechanical impedance at baseline, but group differences are seen after challenge with methacholine. Modeling of the response suggests that variable contributions of airway narrowing and wall compliance are operative in determining overall mechanical impedance of the lung periphery in humans with asthma, likely reflecting the functional consequences of airway inflammation and remodeling.},
  author       = {Kaminsky, DA and Irvin, CG and Lundblad, Lennart and Moriya, HT and Lang, S and Allen, J and Viola, T and Lynn, M and Bates, JHT},
  issn         = {1522-1601},
  keyword      = {forced oscillation technique,impedance,airway remodeling},
  language     = {eng},
  number       = {5},
  pages        = {1849--1858},
  publisher    = {American Physiological Society},
  series       = {Journal of Applied Physiology},
  title        = {Oscillation mechanics of the human lung periphery in asthma},
  url          = {http://dx.doi.org/10.1152/japplphysiol.00300.2004},
  volume       = {97},
  year         = {2004},
}