Document Detail


Dynamic changes in the zone of apposition and diaphragm length during maximal respiratory efforts.
MedLine Citation:
PMID:  8066555     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Clinical tests of diaphragmatic strength are limited by the wide normal variation in maximal pressure which result, in part, from changes in diaphragmatic length. During relaxation at different lung volumes diaphragmatic length (LDI) can be estimated from the length of the zone of apposition (LZapp) and the transverse diameter of the rib cage (DRC). A study was carried out in two subjects using sequential digital radiography at six frames/second to determine whether these relations apply during maximal respiratory efforts which distort the rib cage and diaphragm. METHODS: The length of the anteroposterior contour of the diaphragm and DRC were determined by curve fitting. LZapp was measured with a millimetre rule. RESULTS: A significant correlation was found between LDI and LZapp during both maximal inspiratory and expulsive manoeuvres (R2 = 0.88 and 0.52). LDI was estimated from the measurements of LZapp and DRC using a multiple regression equation derived from measurements during static relaxation. Despite the complex dynamic events at the onset of these "static" manoeuvres, actual LDI correlated strongly with derived LDI using all data for the two manoeuvres in each subject (R2 = 0.95 and 0.84). Measurements with ultrasonography (12 cm linear probe) and magnetometers confirmed the changes in LZapp and DRC during inspiratory and expulsive efforts. CONCLUSIONS: Non-invasive measurements of LZapp and DRC can be used to derive an accurate estimate of diaphragmatic length under dynamic conditions.
Authors:
D K McKenzie; S C Gandevia; R B Gorman; F C Southon
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Thorax     Volume:  49     ISSN:  0040-6376     ISO Abbreviation:  Thorax     Publication Date:  1994 Jul 
Date Detail:
Created Date:  1994-09-19     Completed Date:  1994-09-19     Revised Date:  2010-03-24    
Medline Journal Info:
Nlm Unique ID:  0417353     Medline TA:  Thorax     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  634-8     Citation Subset:  IM    
Affiliation:
Department of Respiratory Medicine, Prince Henry Hospital, University of New South Wales, Sydney, Australia.
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MeSH Terms
Descriptor/Qualifier:
Adult
Angiography, Digital Subtraction / instrumentation
Diaphragm / anatomy & histology*,  radiography,  ultrasonography
Humans
Magnetics
Regression Analysis
Respiratory Mechanics / physiology*
Ribs / radiography
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