Costal and crural diaphragm in early inspiration: free breathing and occlusion

Details

Serval ID
serval:BIB_E4D9172533F5
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Costal and crural diaphragm in early inspiration: free breathing and occlusion
Journal
Journal of Applied Physiology
Author(s)
Easton  P. A., Fitting  J. W., Grassino  A. E.
ISSN
8750-7587 (Print)
Publication state
Published
Issued date
10/1987
Volume
63
Number
4
Pages
1622-8
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Oct
Abstract
Changes in length of costal and crural segments of the canine diaphragm were measured by sonomicrometry within the first 100-300 ms of inspiration during CO2 rebreathing in anesthetized animals. Both segments showed small but significant decreases in end-expiratory length during progressive hypercapnia. Although both costal and crural segments showed electromyographic activity within the first 100 ms of inspiration, in early inspiration crural shortening predominated with minimal costal shortening. Neither segment contracted isometrically early in inspiration in the presence of airway occlusion. The amount of crural shortening during airway occlusion exceeded costal shortening; both segments showed increased shortening with prolonged occlusion and increasing CO2. Costal and crural shortening at 100 ms was not different for unoccluded and occluded states. These observations suggest that neural control patterns evoke discrete and unequal contributions from the diaphragmatic segments at the beginning of an inspiration; the crural segment may be predominately recruited in early inspiration. Despite traditional assumptions about occlusion pressure measurement (P0.1), diaphragm segments do not contract isometrically during early inspiratory effort against an occluded airway.
Keywords
Airway Obstruction/physiopathology Animals Diaphragm/*physiology Dogs Electromyography Hypercapnia/physiopathology Muscle Contraction *Respiration Respiratory Function Tests
Pubmed
Web of science
Create date
25/01/2008 9:43
Last modification date
20/08/2019 16:08
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