Item: Prolonged oxygenation during snow burial; the role of carbon dioxide exclusion
Title: Prolonged oxygenation during snow burial; the role of carbon dioxide exclusion
Proceedings: Proceedings of the 2000 International Snow Science Workshop, October 1-6, Big Sky, Montana
Authors: Martin I. Radwin, M.D, Colin K. Grissom, M.D., Mary Beth Scholand, M.D. and Chris H. Harmston, MSE University of Utah and LDS Hospital, Salt Lake City, Utah
Abstract: Asphyxiation, the cause of death in more than seventy five percent avalanche burial victims, is greatly accelerated by the rapid accumulation of exhaled carbon dioxide in the surrounding air space and snowpack. We hypothesized that complete exclusion of exhaled carbon dioxide during snow burial would allow prolonged oxygenation utilizing the air within the snowpack. Eight healthy volunteers were fully buried for greater than 90 minutes in compacted snow with a density ranging from 300-680kg/m3 at an elevation of 2560m. The 6-men and 2 women breathed on a device containing no air pocket around the inhalation intake and a greatly extended exhalation tube running completely out of the snowpack to remove all exhaled carbon dioxide. Continuous physiologic monitoring included oxygen saturation (Sp02 %), end-tidal C02 (ETC02 in mmHg), inspired C02 (PIC02 in mmHg), ECG, core temperature and respiratory rate. As controls, we studied 5 matched subjects under identical conditions breathing into a small fist-sized air pocket but no carbon dioxide removal device. In the experimental group, the mean burial time was 89 minutes despite the absence of an air pocket. No significant changes occurred in any physiologic parameters in this group compared to baseline. In contrast, the controls remained buried for a mean 10 minutes and became significantly hypercapnic and hypoxic. We conclude that there is sufficient oxygen in a densified snowpack comparable to avalanche debris to sustain normal oxygenation and ventilation for at least 90 minutes during snow burial if exhaled CO2is removed.
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Keywords: snow burial, asphyxiation, carbon dioxide
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