Document Detail

Acute changes of lung volumes and lung mechanics in asthma and in normal subjects.
MedLine Citation:
PMID:  684678     Owner:  NLM     Status:  MEDLINE    
Lung volumes, pulmonary mechanics, and specific airway conductance (sGaw) were studied before and 15 minutes after 200 microgram of aerosol salbutamol in nine asthmatics undergoing mild spontaneous exacerbations of their disease and in five normal subjects. In addition, three of the normal subjects were studied after voluntarily breathing at high lung volumes for one minute. The normal subjects and four of the asthmatics showed no overall changes in lung volumes or pressure-volume (PV) curves after salbutamol, even though airway dilatation was produced in the asthmatic subjects. In another five asthmatics, salbutamol induced a significant fall in the total lung capacity (TLC) in three, and in the residual volume and functional residual capacity in all five. There was a significant displacement of the PV curve downwards and to the right in all five, with increased lung compliance (Cl stat) in two. The fall in TLC could be accounted for by the increase in lung elasticity. There is reason to believe that this change in lung mechanics could be due to the reversal of asthma-induced stress relaxation. Sustained breathing at high lung volume is known to cause stress relaxation of the lung. However, this breathing pattern did not alter the PV curve or TLC in two of three normal subjects, which is consistent with stress relaxation being rapidly reversible. The other normal subject had an acute shift of the PV curve upwards and to the left after breathing at high lung volume. It has been concluded that stress relaxation is usually rapidly reversed but that in some individuals it may only be slowly reversed. This more persistent form of stress relaxation may contribute to the acute changes of TLC found in some asthmatics.
P W Holmes; A H Campbell; C E Barter
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Thorax     Volume:  33     ISSN:  0040-6376     ISO Abbreviation:  Thorax     Publication Date:  1978 Jun 
Date Detail:
Created Date:  1978-10-18     Completed Date:  1978-10-18     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0417353     Medline TA:  Thorax     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  394-400     Citation Subset:  IM    
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MeSH Terms
Airway Resistance
Albuterol / diagnostic use
Asthma / physiopathology*
Forced Expiratory Volume
Functional Residual Capacity
Lung / physiopathology*
Lung Compliance
Middle Aged
Total Lung Capacity
Vital Capacity
Reg. No./Substance:

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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