Document Detail

Changes in relaxation rate with diaphragmatic fatigue in humans.
MedLine Citation:
PMID:  6863095     Owner:  NLM     Status:  MEDLINE    
Maximum relaxation rate (MRR) and the time constant of relaxation (tau) of transdiaphragmatic pressure (Pdi) was measured in four male subjects and compared with the high-to-low frequency ratio (H/L) of the diaphragmatic electromyogram (EMG) as a predictor of diaphragmatic fatigue. Pdi and inspiratory time-to-total breath duration ratios (TI/TT) were varied, and TT and tidal volume were held constant; inspiratory resistances were used to increase Pdi. Studies were performed at various tension-time indices (TTdi = Pdi/Pdimax X TI/TT). Base-line MRR/Pdi was 0.0100 +/- 0.0004 (SE) ms-1, and baseline tau was 53.2 +/- 3.2 ms. At TTdi greater than 0.20, MRR and H/L decreased and tau increased, with maximum changes at the highest TTdi. At TTdi less than 0.20, there was no change in H/L, MRR, or tau. The time course of changes in H/L correlated with those of MRR and tau under fatiguing conditions. In this experimental setting, change in relaxation rate was as useful a predictor of diaphragmatic fatigue as fall in H/L of the diaphragmatic EMG.
S A Esau; F Bellemare; A Grassino; S Permutt; C Roussos; R L Pardy
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology: respiratory, environmental and exercise physiology     Volume:  54     ISSN:  0161-7567     ISO Abbreviation:  J Appl Physiol Respir Environ Exerc Physiol     Publication Date:  1983 May 
Date Detail:
Created Date:  1983-08-11     Completed Date:  1983-08-11     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  7801242     Medline TA:  J Appl Physiol Respir Environ Exerc Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1353-60     Citation Subset:  IM    
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MeSH Terms
Diaphragm / physiology*
Inspiratory Capacity
Muscle Contraction*
Muscle Relaxation*
Tidal Volume

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

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