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Now that’s going above and beyond the call of duty: Four doctors braved the dangers of Everest and scaled the world’s tallest mountain in order to study their tolerance to low oxygen levels experienced near the peak of the 29,000-foot mountain. The doctors, who had spent several weeks acclimatizing to the thin atmosphere, had the lowest blood oxygen levels ever recorded in a healthy, non-hibernating mammal. “You sometimes see levels this low in people who are dying because they’ve had a cardiac arrest,” says team member Mike Grocott…. “We were able to talk, walk, take the blood gas and think clearly with these levels” [New Scientist].

The doctors couldn’t take blood samples on the summit because conditions were too severe, with high winds and temperatures of around -13 degrees Fahrenheit. But once they descended to about 27,500 feet the doctors removed their gloves, unzipped their down suits and drew blood from the femoral artery in the groin. The samples were then carried by Sherpas back down the mountain and analysed within two hours at a science lab set up at the team’s camp [BBC News] at about 21,000 feet. Although the climbers had used oxygen tanks during their ascent, they removed their masks twenty minutes before conducting the test to avoid skewing the readings. The findings, they say, may have implications for doctors who worry about the blood oxygen levels of critically ill patients.

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A new study has found that 1.3 percent of the ambitious climbers who test themselves on the world’s highest mountain, Mount Everest, will die before returning to base camp, a higher rate than that of other peaks. The host of hazards awaiting those who dare to climb the 29,000-foot (8,850 meter) Himalayan mountain include extreme cold, whipping winds, changing weather, treacherous climbs and avalanches. Oxygen content in the air is only a third of that at sea level [Reuters]. But the main cause of death isn’t avalanches, falls, or respiratory problems brought on by the thin atmosphere, researchers found–nor is it monster attacks. “Nobody was attacked by any Yeti or anything else” [Reuters], study coauthor Paul Firth helpfully added.

Instead, the most frequent cause of death is brain swelling brought on by the altitude, which is accompanied by confusion and lack of coordination. Study coauthor Kent Moore explains: “With the low barometric pressure and lack of oxygen, there tends to be a seepage of fluid out of the blood vessels. When this happens in the brain, it causes swelling. It tends to impair cognitive function. That’s probably what causes a lot of the deaths.” Climbers with this problem fall behind, become lethargic, and may become disoriented – none of which has anything to do with their level of physical fitness [Canwest News Service].

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