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A reevaluation of the validity of unrestrained plethysmography in mice

Lundblad, Lennart LU ; Irvin, CG; Adler, A and Bates, JHT (2002) In Journal of Applied Physiology 93(4). p.1198-1207
Abstract
Presently, unrestrained plethysmography is widely used to assess bronchial responsiveness in mice. An empirical quantity known as enhanced pause is derived from the plethysmographic box pressure [P-b( t), where t is time] and assumed to be an index of bronchoconstriction. We show that P-b(t) is determined largely by gas conditioning when normal mice breathe spontaneously inside a closed chamber in which the air is at ambient conditions. When the air in the chamber is heated and humidified to body conditions, the changes in P-b(t) are reduced by about two-thirds. The remaining changes are thus due to gas compression and expansion within the lung and are amplified when the animals breathe through increased resistances. We show that the time... (More)
Presently, unrestrained plethysmography is widely used to assess bronchial responsiveness in mice. An empirical quantity known as enhanced pause is derived from the plethysmographic box pressure [P-b( t), where t is time] and assumed to be an index of bronchoconstriction. We show that P-b(t) is determined largely by gas conditioning when normal mice breathe spontaneously inside a closed chamber in which the air is at ambient conditions. When the air in the chamber is heated and humidified to body conditions, the changes in P-b(t) are reduced by about two-thirds. The remaining changes are thus due to gas compression and expansion within the lung and are amplified when the animals breathe through increased resistances. We show that the time integral of P-b(t) over inspiration is accurately predicted by a term containing airway resistance, functional residual capacity, and tidal volume. We conclude that unrestrained plethysmography can be used to accurately characterize changes in airway resistance only if functional residual capacity and tidal volume are measured independently and the chamber gas is preconditioned to body temperature and humidity. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
airway resistance, Boyle's law, gas conditioning
in
Journal of Applied Physiology
volume
93
issue
4
pages
1198 - 1207
publisher
American Physiological Society
external identifiers
  • wos:000178034600004
  • pmid:12235015
  • scopus:0036785044
ISSN
1522-1601
DOI
10.1152/japplphysiol.00080.2002
language
English
LU publication?
yes
id
a5ca24c3-47be-40fb-a09d-052ca80fa660 (old id 328587)
alternative location
http://jap.physiology.org/cgi/reprint/00080.2002v1
date added to LUP
2007-11-02 09:55:20
date last changed
2017-12-10 03:47:28
@article{a5ca24c3-47be-40fb-a09d-052ca80fa660,
  abstract     = {Presently, unrestrained plethysmography is widely used to assess bronchial responsiveness in mice. An empirical quantity known as enhanced pause is derived from the plethysmographic box pressure [P-b( t), where t is time] and assumed to be an index of bronchoconstriction. We show that P-b(t) is determined largely by gas conditioning when normal mice breathe spontaneously inside a closed chamber in which the air is at ambient conditions. When the air in the chamber is heated and humidified to body conditions, the changes in P-b(t) are reduced by about two-thirds. The remaining changes are thus due to gas compression and expansion within the lung and are amplified when the animals breathe through increased resistances. We show that the time integral of P-b(t) over inspiration is accurately predicted by a term containing airway resistance, functional residual capacity, and tidal volume. We conclude that unrestrained plethysmography can be used to accurately characterize changes in airway resistance only if functional residual capacity and tidal volume are measured independently and the chamber gas is preconditioned to body temperature and humidity.},
  author       = {Lundblad, Lennart and Irvin, CG and Adler, A and Bates, JHT},
  issn         = {1522-1601},
  keyword      = {airway resistance,Boyle's law,gas conditioning},
  language     = {eng},
  number       = {4},
  pages        = {1198--1207},
  publisher    = {American Physiological Society},
  series       = {Journal of Applied Physiology},
  title        = {A reevaluation of the validity of unrestrained plethysmography in mice},
  url          = {http://dx.doi.org/10.1152/japplphysiol.00080.2002},
  volume       = {93},
  year         = {2002},
}