Item: O2 and co2 levels with the black diamond avalung during human snow burials lasting up to one hour
Title: O2 and co2 levels with the black diamond avalung during human snow burials lasting up to one hour
Proceedings: Proceedings of the 1998 International Snow Science Workshop, Sunriver, Oregon
Authors: J. Margid, N. Beidleman, C. Harmston, C.T. Crowley, C. Hatton T.J. Crowley, Black Diamond Equipment, Ltd., Salt Lake City, Utah, USA, Big Air Designs, Aspen Colorado, USA, TJ Crowley Corp, Denver, Colorado, USA, email: firstname.lastname@example.org
Abstract: The patented AvaLung aims to permit an avalanche victim to breathe the air contained in snow. Hypotheses: (1) Human blood Oz saturation will be about equal across four tests: open atmosphere breathing through the mouthpiece only, open-atmosphere breathing through an AvaLung, breathing during head-out snow burials, and breathing during full burial. (2) Across those tests CO2 concentrations will remain about equal. Methods: Three highly conditioned males, 30 - 40 years old, consented to testing at Mt. Hood, Oregon, (2225 m altitude). Snow density was 600-610 kglm3. Burials were 0.3 - 1 m deep at the chest. Testers measured pulse and respiratory rates, blood O2 saturation, and CO2 concentration of inhaled and exhaled air. Intercoms permitted tester-subject communication. Results: Two subjects' blood O2saturation remained over 90 % through full burials of 10 and 63 minutes, respectively, supporting Hypothesis 1. A third subject breathed without problem, although saturation fell to 81 % during 45 minutes of full burial; a valve apparently had malfunctioned in his prototype AvaLung. Regarding Hypothesis 2, CO2 in inhaled air rose from 0% during mouthpiece-only breathing to 0.8 - 1.2 % with AvaLung breathing in open atmosphere, a "minor dead space effect. During burials inhaled CO2 reached 4.9% in two Subjects, and 6.6% in the subject with the malfunction. Pulse rates were elevated during burials, probably reflecting anxiety. Conclusions: The prototype AvaLung supported life through burials of usually-fatal duration. O2availability was excellent. Results suggested slow accumulation of CO2 around buried subjects.
Keywords: avalanche accidents, avalanche safety, avalanche rescue, snow permeability
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