Nonuniform expansion of constricted dog lungs

Rolf D. Hubmayr, Mark J. Hill, Theodore A. Wilson

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

The parenchymal marker technique was used to measure regional tidal volumes of samples of lung parenchyma in four open-chest supine dogs. Radiopaque markers that had been implanted in the lower lobe were tracked by biplane video fluoroscopy during sinusoidal volume oscillations at tidal volumes of ~20% of total lung capacity and frequencies of 1-40 breaths/min before and after methacholine was administered by aerosol. The volumes of tetrahedrons with apexes at four markers were computed, and sine waves were fit to the data for volume vs. time for each tetrahedron. The ratio of mean regional volume to mean airway pressure decreased by 10-45% after exposure to methacholine. Dynamic lung elastance and resistance of the constricted lungs were larger than control, and both were frequency dependent. Regional elastance and resistance varied considerably among tetrahedrons, and these were also frequency dependent. The data were fit by a model in which tissue elastance was uniform and nearly equal to elastance in the control state, but small airway resistance was high and variable. We conclude that the lung contracts under bronchoconstriction but that the increased dynamic elastance and resistance of the constricted lung may be primarily the result of nonuniform increased airway resistance at the level of the terminal bronchioles.

Original languageEnglish (US)
Pages (from-to)522-530
Number of pages9
JournalJournal of Applied Physiology
Volume80
Issue number2
StatePublished - Feb 1996
Externally publishedYes

Fingerprint

Dogs
Lung
Airway Resistance
Methacholine Chloride
Tidal Volume
Bronchioles
Total Lung Capacity
Bronchoconstriction
Fluoroscopy
Aerosols
Thorax
Pressure

Keywords

  • airways
  • asthma
  • bronchoconstriction
  • elastance
  • resistance
  • viscance

ASJC Scopus subject areas

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

Cite this

Hubmayr, R. D., Hill, M. J., & Wilson, T. A. (1996). Nonuniform expansion of constricted dog lungs. Journal of Applied Physiology, 80(2), 522-530.

Nonuniform expansion of constricted dog lungs. / Hubmayr, Rolf D.; Hill, Mark J.; Wilson, Theodore A.

In: Journal of Applied Physiology, Vol. 80, No. 2, 02.1996, p. 522-530.

Research output: Contribution to journalArticle

Hubmayr, RD, Hill, MJ & Wilson, TA 1996, 'Nonuniform expansion of constricted dog lungs', Journal of Applied Physiology, vol. 80, no. 2, pp. 522-530.
Hubmayr RD, Hill MJ, Wilson TA. Nonuniform expansion of constricted dog lungs. Journal of Applied Physiology. 1996 Feb;80(2):522-530.
Hubmayr, Rolf D. ; Hill, Mark J. ; Wilson, Theodore A. / Nonuniform expansion of constricted dog lungs. In: Journal of Applied Physiology. 1996 ; Vol. 80, No. 2. pp. 522-530.
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