Document Detail

Diaphragmatic responses to body position changes in obese patients with obstructive sleep apnea.
MedLine Citation:
PMID:  3942377     Owner:  NLM     Status:  MEDLINE    
Patients with severe obesity and obstructive sleep apnea (OSA) have been shown to have abnormalities in respiratory muscle function and respiratory control. The present study was done to evaluate diaphragmatic function and the diaphragm fiber-length-compensating reflex in morbidly obese patients with OSA (1). Twelve normal subjects and 13 morbidly obese patients with OSA were studied in recumbent and upright positions. In the normal subjects, the diaphragm fiber-length-compensating reflex operated normally causing the diaphragm's inspiratory EMG to increase when the diaphragm's fibers shortened with assumption of the upright position. However, 8 of the 13 obese patients with OSA showed a decrease rather than an increase in the inspiratory diaphragmatic EMG on assuming the upright posture. Further data indicate greater diaphragmatic efficiency in the upright than in the supine position in a majority of the obese patients, a reversal of the normal response. Two possible explanations of these observations are: an abnormality of central respiratory control in obese patients with OSA and overstretching of the diaphragm in the recumbent obese patient. The observation of reduced maximal transdiaphragmatic pressures in the recumbent position in some of the obese patients with OSA supports the second explanation. Diaphragmatic overstretching may be an important mechanism in the development of hypoventilation in the morbidly obese.
J T Sharp; W S Druz; V R Kondragunta
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American review of respiratory disease     Volume:  133     ISSN:  0003-0805     ISO Abbreviation:  Am. Rev. Respir. Dis.     Publication Date:  1986 Jan 
Date Detail:
Created Date:  1986-02-13     Completed Date:  1986-02-13     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370523     Medline TA:  Am Rev Respir Dis     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  32-7     Citation Subset:  AIM; IM    
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MeSH Terms
Diaphragm / physiopathology*
Hypercapnia / physiopathology
Lung Volume Measurements
Mechanoreceptors / physiopathology
Middle Aged
Obesity / complications,  physiopathology*
Phrenic Nerve / physiopathology
Reflex / physiology
Sleep Apnea Syndromes / etiology,  physiopathology*
Grant Support

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

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