Document Detail

Impedance measurement during air and helium-oxygen breathing before and after salbutamol in COPD patients.
MedLine Citation:
PMID:  1555329     Owner:  NLM     Status:  MEDLINE    
1. The forced oscillation technique is an effort-independent method used to characterize the mechanical impedance of the respiratory system. To support the hypothesis that non-invasive partitioning of total pulmonary resistance is possible by this technique, impedance was measured during air breathing and after equilibration with a mixture of 80% helium (He) and 20% oxygen (O2) in 21 chronic obstructive pulmonary disease (COPD) patients by means of a forced pseudo-random noise pressure signal over a frequency spectrum from 4 to 52 Hz. Furthermore, during inhalation of both gas mixtures impedance was determined before and after inhalation of 0.400 mg Salbutamol. 2. He + O2 breathing caused less negative frequency dependence of resistance and a significant decrease in reactance over the range 16-52 Hz. Inhalation of Salbutamol caused a marked increase in reactance values over the range 8-40 Hz. However after equilibration with the He + O2 mixture, Salbutamol caused a significant decrease in resistance and a significant increase in reactance at all frequencies. 3. The results during He + O2 breathing are in accordance with a partitioning of airways resistance into central and peripheral components. The decrease in reactance during He + O2 can be explained by a density dependent decrease in inductive reactance. By comparing the impedance data during air and He + O2 breathing, it can be concluded that a distribution of pulmonary resistance with minimal losses in the larger airways is more sensitive for detecting changes in the peripheral airways in COPD patients.
E F Wouters; F J Lándsér; A H Polko; B F Visser
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Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; Journal Article    
Journal Detail:
Title:  Clinical and experimental pharmacology & physiology     Volume:  19     ISSN:  0305-1870     ISO Abbreviation:  Clin. Exp. Pharmacol. Physiol.     Publication Date:  1992 Feb 
Date Detail:
Created Date:  1992-05-04     Completed Date:  1992-05-04     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0425076     Medline TA:  Clin Exp Pharmacol Physiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  95-101     Citation Subset:  IM    
Department of Pulmonary Diseases, University Limburg, Maastricht, The Netherlands.
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MeSH Terms
Airway Resistance / drug effects*
Albuterol / pharmacology*
Lung Compliance
Lung Diseases, Obstructive / physiopathology*
Middle Aged
Reg. No./Substance:
18559-94-9/Albuterol; 7440-59-7/Helium; 7782-44-7/Oxygen

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

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