Climbers who conquer the world's highest peak are about one-third as likely to die during descent if they use supplemental oxygen during the journey than if they rely only on the limited oxygen in thin mountain air, a University of Washington researcher has found.
Of the 1,173 people who successfully scaled Mount Everest on the Nepal-Tibet border from 1978 through 1999, the death rate during descent was 8.3 percent for those not using supplemental oxygen, compared with 3 percent for those using extra oxygen, said Raymond Huey, a UW zoology professor. Supplemental oxygen was used by 1,077 climbers who reached Everest's summit and 32 of them died during the descent, he found, while eight of the 96 climbers who did not use supplemental oxygen perished on the way down.
A similar, more striking, pattern emerged on K2, the world's second-highest mountain, which is on the Pakistan-China border about 800 miles from Everest. On the steeper, more rugged K2, none of the 47 successful climbers who used supplemental oxygen died during descent. But 22 of 117, or nearly one in five (18.8 percent), of those not using bottled oxygen perished after reaching the summit. Many of those deaths came during two violent storms in 1986 and 1995.
The comparisons only used figures for climbers who successfully reached the two peaks because data on unsuccessful expeditions were not readily available.
The research by Huey and Xavier Eguskitza, a Himalaya mountaineering historian, is the first to quantify the effects of supplemental oxygen in climbing Everest and K2. It is published in the July 12 issue of the Journal of the American Medical Association.
"The finding that climbers using supplemental oxygen have higher survival rates might reflect the benefits of extra oxygen in reducing the physical and mental deterioration that is inevitable at extreme altitude," Huey said. "But our data don't necessarily imply cause and effect. Another explanation is that climbers using
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Contact: Vince Stricherz
vinces@u.washington.edu
206-543-2580
University of Washington
10-Jul-2000