Document Detail


Respiration during snow burial using an artificial air pocket.
MedLine Citation:
PMID:  10807386     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
CONTEXT: Asphyxia is the most common cause of death after avalanche burial. A device that allows a person to breathe air contained in snow by diverting expired carbon dioxide (CO2) away from a 500-cm3 artificial inspiratory air pocket may improve chances of survival in avalanche burial.
OBJECTIVE: To determine the duration of adequate oxygenation and ventilation during burial in dense snow while breathing with vs without the artificial air pocket device.
DESIGN: Field study of physiologic respiratory measures during snow burial with and without the device from December 1998 to March 1999. Study burials were terminated at the subject's request, when oxygen saturation as measured by pulse oximetry (SpO2) dropped to less than 84%, or after 60 minutes elapsed.
SETTING: Mountainous outdoor site at 2385 m elevation, with an average barometric pressure of 573 mm Hg.
PARTICIPANTS: Six male and 2 female volunteers (mean age, 34.6 years; range, 28-39 years).
MAIN OUTCOME MEASURES: Burial time, SpO2, partial pressure of end-tidal CO2 (ETCO2), partial pressure of inspiratory CO2 (PICO2), respiratory rate, and heart rate at baseline (in open atmosphere) and during snow burial while breathing with the device and without the device but with a 500-cm3 air pocket in the snow.
RESULTS: Mean burial time was 58 minutes (range, 45-60 minutes) with the device and 10 minutes (range, 5-14 minutes) without it (P=.001). A mean baseline SpO2 of 96% (range, 90%-99%) decreased to 90% (range, 77%-96%) in those buried with the device (P=.01) and to 84% (range, 79%-92%) in the control burials (P=.02). Only 1 subject buried with the device, but 6 control subjects buried without the device, decreased SpO2 to less than 88% (P=.005). A mean baseline ETCO2 of 32 mm Hg (range, 27-38 mm Hg) increased to 45 mm Hg (range, 32-53 mm Hg) in the burials with the device (P=.02) and to 54 mm Hg (range, 44-63 mm Hg) in the control burials (P=.02). A mean baseline PICO2 of 2 mm Hg (range, 0-3 mm Hg) increased to 32 mm Hg (range, 20-44 mm Hg) in the burials with the device (P=.01) and to 44 mm Hg (range, 37-50 mm Hg) in the control burials (P=.02). Respiratory and heart rates did not change in burials with the device but significantly increased in control burials.
CONCLUSIONS: In our study, although hypercapnia developed, breathing with the device during snow burial considerably extended duration of adequate oxygenation compared with breathing with an air pocket in the snow. Further study will be needed to determine whether the device improves survival during avalanche burial.
Authors:
C K Grissom; M I Radwin; C H Harmston; E L Hirshberg; T J Crowley
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  JAMA     Volume:  283     ISSN:  0098-7484     ISO Abbreviation:  JAMA     Publication Date:  2000 May 
Date Detail:
Created Date:  2000-05-16     Completed Date:  2000-05-16     Revised Date:  2014-09-17    
Medline Journal Info:
Nlm Unique ID:  7501160     Medline TA:  JAMA     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2266-71     Citation Subset:  AIM; IM    
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MeSH Terms
Descriptor/Qualifier:
Adult
Asphyxia / prevention & control*
Disasters*
Equipment Design
Female
Heart Rate
Humans
Male
Mountaineering
Respiration*
Skiing
Snow*
Ventilators, Mechanical*
Comments/Corrections
Comment In:
JAMA. 2000 May 3;283(17):2293-4   [PMID:  10807391 ]
JAMA. 2000 Sep 13;284(10):1242-3; author reply 1243-4   [PMID:  10979104 ]
JAMA. 2000 Sep 13;284(10):1243; author reply 1243-4   [PMID:  10979105 ]

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


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