The Bronchodilator Response of In Vivo Specific Airway Compliance in Adults with Asthma.
Summary of "The Bronchodilator Response of In Vivo Specific Airway Compliance in Adults with Asthma."
A new technique has been developed to determine in vivo airway compliance in humans that is specific to airway size and transpulmonary pressure, and can be represented as a three-dimensional surface. As yet, the ability of this technique to detect changes in specific airway compliance with disease status has not been demonstrated. The aim of this study was to assess whether this technique could determine changes in airway compliance which are thought to occur with altered smooth muscle tone in adults with asthma. Airway compliance was measured and displayed as a surface in adults with asthma before and after a reduction in smooth muscle tone by bronchodilator administration. Compliance, with respect to airway size, was calculated at three specific lung volumes; functional residual capacity (FRC), total lung capacity (TLC), and midway between FRC and TLC (MID). After bronchodilator, airway compliance increased at FRC and MID in the smaller airways (<3 mm). Furthermore, airway compliance under both conditions was greater in the smaller airways compared to the larger airways. In conclusion, our method may have future utility in assessing changes in airway compliance in respiratory diseases such as asthma.
Affiliation
The Department of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia.
Journal Details
This article was published in the following journal.
Name: Annals of biomedical engineering
ISSN: 1521-6047
Pages:
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/21184178
- DOI: http://dx.doi.org/10.1007/s10439-010-0206-0
Medical and Biotech [MESH] Definitions
Compliance
Distensibility measure of a chamber such as the lungs (LUNG COMPLIANCE) or bladder. Compliance is expressed as a change in volume per unit change in pressure.
Asthma
A form of bronchial disorder with three distinct components: airway hyper-responsiveness (RESPIRATORY HYPERSENSITIVITY), airway INFLAMMATION, and intermittent AIRWAY OBSTRUCTION. It is characterized by spasmodic contraction of airway smooth muscle, WHEEZING, and dyspnea (DYSPNEA, PAROXYSMAL).
Work Of Breathing
RESPIRATORY MUSCLE contraction during INHALATION. The work is accomplished in three phases: LUNG COMPLIANCE work, that required to expand the LUNGS against its elastic forces; tissue resistance work, that required to overcome the viscosity of the lung and chest wall structures; and AIRWAY RESISTANCE work, that required to overcome airway resistance during the movement of air into the lungs. Work of breathing does not refer to expiration, which is entirely a passive process caused by elastic recoil of the lung and chest cage. (Guyton, Textbook of Medical Physiology, 8th ed, p406)
Bronchial Hyperreactivity
Tendency of the smooth muscle of the tracheobronchial tree to contract more intensely in response to a given stimulus than it does in the response seen in normal individuals. This condition is present in virtually all symptomatic patients with asthma. The most prominent manifestation of this smooth muscle contraction is a decrease in airway caliber that can be readily measured in the pulmonary function laboratory.
Airway Remodeling
The structural changes in the number, mass, size and/or composition of the airway tissues.
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