Airway response to deep inspiration: Role of inflation pressure

Research output: Contribution to journalArticle

Abstract

Deep inspirations (DIs) have been shown to have both bronchoprotective and bronchodilator effects in healthy subjects; however, the bronchodilator effects of a DI appear to be impaired in asthmatic compared with healthy subjects. Because the ability to generate high transpulmonary pressures at total lung capacity depends on both the lung properties and voluntary effort, we wondered how the response of airways to DI might be altered if the maneuver were done with less than maximal inflation. The present work was undertaken to examine the effects of varying the magnitude of lung inflation during the DI maneuver on subsequent airway caliber. In five anesthetized and ventilated dogs during methacholine infusion, changes in airway size after DIs of increasing magnitude were measured over the subsequent 5-min period using high-resolution computed tomography. Results show that the magnitude of lung inflation is extremely important, leading to a qualitative change in the airway response. A large DI (45 cmH2O airway pressure) caused subsequent airway dilation, whereas smaller DIs (≤35 cmH2O) caused bronchoconstriction. The precise mechanism underlying these observations is uncertain, but it seems to be related to an interaction between intrinsic properties of the contracted airway smooth muscle and the response to mild stretch.

Original languageEnglish (US)
Pages (from-to)2574-2578
Number of pages5
JournalJournal of applied physiology
Volume91
Issue number6
StatePublished - Dec 13 2001

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Keywords

  • Asthma
  • Bronchoconstriction
  • High-resolution computed tomography
  • Lung inflation
  • Smooth muscle

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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