Document Detail


Effects of the self-contained breathing apparatus on left-ventricular function at rest and during graded exercise.
MedLine Citation:
PMID:  19767797     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The purpose of this study was to examine the effects of the self-contained breathing apparatus (SCBA) on left-ventricular (LV) function at rest and during mild- to moderate-intensity exercise, using 2-dimensional echocardiography. Twenty-three healthy male volunteers exercised on a stair-climber at work rates equivalent to 50%, 60%, 70%, and 80% of peak oxygen consumption. Esophageal pressure LV diastolic and systolic cavity areas, and myocardial areas were acquired during the final minute of each stage of exercise. As expected, the esophageal pressure response during SCBA breathing revealed significantly lower (more negative) inspiratory pressures and higher (more positive) expiratory pressures and, consequently, higher pressure swings, than free breathing (FB). End-diastolic cavity area (EDCA) and end-systolic cavity area (ESCA) were lower with the SCBA than with FB. LV contractility was higher (p < 0.05) with the SCBA, which can partially be explained by decreases in end-systolic wall stress. Therefore, the SCBA was found to decrease LV preload during moderate-intensity exercise, but did not negatively affect stroke area because of a similar reduction in ESCA.
Authors:
Jonathan R Mayne; Mark J Haykowsky; Michael D Nelson; Timothy C Hartley; Scott J Butcher; Richard L Jones; Stewart R Petersen
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Applied physiology, nutrition, and metabolism = Physiologie appliquée, nutrition et métabolisme     Volume:  34     ISSN:  1715-5312     ISO Abbreviation:  -     Publication Date:  2009 Aug 
Date Detail:
Created Date:  2009-09-21     Completed Date:  2009-10-15     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101264333     Medline TA:  Appl Physiol Nutr Metab     Country:  Canada    
Other Details:
Languages:  eng     Pagination:  625-31     Citation Subset:  IM    
Affiliation:
Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB T6G 2H9, Canada.
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MeSH Terms
Descriptor/Qualifier:
Adult
Echocardiography
Esophagus / physiology
Exercise*
Exhalation
Fires
Humans
Inhalation
Male
Middle Aged
Myocardial Contraction
Occupational Health
Oxygen Consumption
Pressure
Respiratory Protective Devices*
Spirometry
Ventricular Function, Left*

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


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