Journal of Applied Physiology Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Appl Physiol 57: 182-190, 1984;
8750-7587/84 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Bazzy, A. R.
Right arrow Articles by Haddad, G. G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bazzy, A. R.
Right arrow Articles by Haddad, G. G.

Journal of Applied Physiology, Vol 57, Issue 1 182-190, Copyright © 1984 by American Physiological Society

ARTICLES

Diaphragmatic fatigue in unanesthetized adult sheep

A. R. Bazzy and G. G. Haddad

We studied diaphragmatic muscle function during inspiratory flow resistive (IFR) loaded breathing in unanesthetized sheep. We measured the change in transdiaphragmatic pressure (dPdi) and arterial blood gas tensions and recorded diaphragmatic electromyogram (EMG) from electrodes implanted on the muscle. We found that, with IFR loads less than 150 cmH2O X l-1 X s, dPdi and the integrated EMG increased, reached a plateau, and were maintained at high levels. The centroid frequency (fc) of the EMG power spectrum did not consistently change. With IFR loads greater than 150 cmH2O X l-1 X s, O2 was administered to prevent hypoxia, cyanosis, and agitation. With these loads, dPdi increased severalfold above base line, reached a plateau, and then started to decrease. Arterial PCO2 increased sharply at the time when dPdi decreased. The integrated EMG (iEMG) and fc started to decrease gradually 10-20 min before dPdi started to decrease. We conclude that 1) the diaphragm is capable of generating large pressures for prolonged periods with no evidence of fatigue; 2) with very high IFR loads, mechanical failure of the diaphragm can occur in the unanesthetized awake sheep; 3) diaphragmatic fatigue is associated with acute hypercapnia and therefore failure of the entire respiratory pump; and 4) a decrease in iEMG and a concommitant shift in the power spectrum density towards lower frequencies precede the mechanical failure of the diaphragm.


This article has been cited by other articles:


Home page
 Am. J. Respir. Crit. Care Med.Home page
H. ROLLIER, A. BISSCHOP, G. GAYAN-RAMIREZ, R. GOSSELINK, and M. DECRAMER
Low Load Inspiratory Muscle Training Increases Diaphragmatic Fiber Dimensions in Rats
Am. J. Respir. Crit. Care Med., March 1, 1998; 157(3): 833 - 839.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
D. K. McKenzie, G. M. Allen, J. E. Butler, and S. C. Gandevia
Task failure with lack of diaphragm fatigue during inspiratory resistive loading in human subjects
J Appl Physiol, June 1, 1997; 82(6): 2011 - 2019.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online