Low-frequency pulmonary impedance in rabbits and its response to inhaled methacholine

Robert Tepper, J. Sato, B. Suki, J. G. Martin, J. H T Bates

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

We assessed pulmonary mechanics in six open-chest rabbits (3 young and 3 adult) by the forced oscillation technique between 0.16 and 10.64 Hz. Under control conditions, pulmonary resistance (RL) decreased markedly between 0.16 and 4 Hz, after which it became reasonably constant. Measurements of alveolar pressure from two alveolar capsules in each rabbit showed that the large decrease of RL with increasing frequency below 4 Hz was due to lung tissue rheology and that tissue resistance was close to zero above 4 Hz. Estimates of resistance and elastance, also obtained by fitting tidal ventilation data at 1 Hz to the equation of the linear single-compartment model, gave values for RL motion that were slightly higher than those obtained by forced oscillations at the same frequency, presumably because of the flow dependence of airways resistance. After treatment with increasing doses of aerosolized methacholine, RL and pulmonary elastance between 0.16 and 1.34 Hz progressively increased, as did the point at which the pulmonary reactance crossed zero (the resonant frequency). The alveolar pressure measurements showed the lung to become increasingly inhomogeneously ventilated in all six animals, whereas in the three younger rabbits lobar atelectasis developed at high methacholine concentrations and the alveolar capsules ceased to communicate with the central airways. We conclude that the low frequency pulmonary impedance of rabbits exhibits the same qualitative features observed in other species and that it is a sensitive indicator of the changes in pulmonary mechanics occurring during bronchoconstriction.

Original languageEnglish (US)
Pages (from-to)290-295
Number of pages6
JournalJournal of Applied Physiology
Volume73
Issue number1
StatePublished - 1992
Externally publishedYes

Fingerprint

Methacholine Chloride
Electric Impedance
Rabbits
Lung
Mechanics
Capsules
Pressure
Airway Resistance
Bronchoconstriction
Pulmonary Atelectasis
Rheology
Ventilation
Young Adult
Thorax

Keywords

  • airways resistance
  • forced oscillation technique
  • pulmonary elastance
  • tissue resistance

ASJC Scopus subject areas

  • Endocrinology
  • Physiology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Tepper, R., Sato, J., Suki, B., Martin, J. G., & Bates, J. H. T. (1992). Low-frequency pulmonary impedance in rabbits and its response to inhaled methacholine. Journal of Applied Physiology, 73(1), 290-295.

Low-frequency pulmonary impedance in rabbits and its response to inhaled methacholine. / Tepper, Robert; Sato, J.; Suki, B.; Martin, J. G.; Bates, J. H T.

In: Journal of Applied Physiology, Vol. 73, No. 1, 1992, p. 290-295.

Research output: Contribution to journalArticle

Tepper, R, Sato, J, Suki, B, Martin, JG & Bates, JHT 1992, 'Low-frequency pulmonary impedance in rabbits and its response to inhaled methacholine', Journal of Applied Physiology, vol. 73, no. 1, pp. 290-295.
Tepper, Robert ; Sato, J. ; Suki, B. ; Martin, J. G. ; Bates, J. H T. / Low-frequency pulmonary impedance in rabbits and its response to inhaled methacholine. In: Journal of Applied Physiology. 1992 ; Vol. 73, No. 1. pp. 290-295.
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