| Physiological responses and air consumption during simulated firefighting tasks in a subway system. | |
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MedLine Citation:
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PMID: 20962923 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Professional firefighters (33 men, 3 women), ranging in age from 30 to 53 years, participated in a simulation of a subway system search and rescue while breathing from their self-contained breathing apparatus (SCBA). We tested the hypothesis that during this task, established by expert firefighters to be of moderate intensity, the rate of air consumption would exceed the capacity of a nominal 30-min cylinder. Oxygen uptake, carbon dioxide output, and air consumption were measured with a portable breath-by-breath gas exchange analysis system, which was fully integrated with the expired port of the SCBA. The task involved descending a flight of stairs, walking, performing a search and rescue, retreat walking, then ascending a single flight of stairs to a safe exit. This scenario required between 9:56 and 13:24 min:s (mean, 12:10 ± 1:10 min:s) to complete, with an average oxygen uptake of 24.3 ± 4.5 mL kg(-1) min(-1) (47 ± 10 % peak oxygen uptake) and heart rate of 76% ± 7% of maximum. The highest energy requirement was during the final single-flight stair climb (30.4 ± 5.4 mL kg(-1) min(-1)). The average respiratory exchange ratio (carbon dioxide output/oxygen uptake) throughout the scenario was 0.95 ± 0.08, indicating a high carbon dioxide output for a relatively moderate average energy requirement. Air consumption from the nominal "30-min" cylinder averaged 51% (range, 26%-68%); however, extrapolation of these rates of consumption suggested that the low-air alarm, signalling that only 25% of the air remains, would have occurred as early as 11 min for an individual with the highest rate of air consumption, and at 16 min for the group average. These data suggest that even the moderate physical demands of walking combined with search and rescue while wearing full protective gear and breathing through the SCBA impose considerable physiological strain on professional firefighters. As well, the rate of air consumption in these tasks classed as moderate, compared with high-rise firefighting, would have depleted the air supply well before the nominal time used to describe the cylinders. |
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Authors:
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F Michael Williams-Bell; Geoff Boisseau; John McGill; Andrew Kostiuk; Richard L Hughson |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Applied physiology, nutrition, and metabolism = Physiologie appliquée, nutrition et métabolisme Volume: 35 ISSN: 1715-5312 ISO Abbreviation: Appl Physiol Nutr Metab Publication Date: 2010 Oct |
Date Detail:
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Created Date: 2010-10-21 Completed Date: 2010-12-10 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101264333 Medline TA: Appl Physiol Nutr Metab Country: Canada |
Other Details:
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Languages: eng Pagination: 671-8 Citation Subset: IM |
Affiliation:
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Faculty of Applied Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adult Anthropometry Carbon Dioxide / metabolism Energy Metabolism / physiology Female Fires* Humans Male Middle Aged Occupational Exposure Oxygen Consumption / physiology* Physical Exertion / physiology* Railroads* Respiratory Protective Devices* |
| Chemical | |
Reg. No./Substance:
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124-38-9/Carbon Dioxide |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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