Document Detail


In-phase rejection requirements for measuring respiratory input impedance.
MedLine Citation:
PMID:  6706784     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Respiratory flow is commonly obtained by measuring the pressure difference across a pneumotachograph. When respiratory input impedance is studied, that pressure difference may be very small with respect to the absolute pressure swings inside the pneumotachograph. Then the in-phase rejection of the differential pressure transducer is expected to markedly influence the accuracy of the data. The problem was investigated by computer simulation and by measurements on a mechanical analog of the respiratory system made of a resistance, an inertance, and a compliance arranged in series. Both studies demonstrated that comparatively small differences in the volumes of the chambers or in the lengths or diameters of the connecting tubes led to artifactual frequency dependence of resistance and serious misestimation of compliance and inertance. Errors were larger when the resistance of the pneumotachograph was smaller and the impedance of the subject larger. In practice, with usual pneumotachographs accurate impedance measurements require using the most symmetrical transducers presently available (common-mode rejection ratio of about 70 dB at 30 Hz).
Authors:
R Peslin; P Jardin; C Duvivier; P Begin
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of applied physiology: respiratory, environmental and exercise physiology     Volume:  56     ISSN:  0161-7567     ISO Abbreviation:  J Appl Physiol     Publication Date:  1984 Mar 
Date Detail:
Created Date:  1984-05-24     Completed Date:  1984-05-24     Revised Date:  2000-12-18    
Medline Journal Info:
Nlm Unique ID:  7801242     Medline TA:  J Appl Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  804-9     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Airway Resistance*
Methods
Models, Biological
Physiology / instrumentation

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


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