December 10, 2008
Study Finds Brain-Swelling Linked To Deaths On Everest
Researchers seeking to find the cause of many deaths of people climbing Mount Everest have made a connection to a brain-swelling condition caused by low oxygen levels in high altitudes.
Contrary to previous notions about these deaths, the team found that many were not caused by avalanches, falling ice and pulmonary oedema (lung problems).
"We know that climbing Mount Everest is dangerous because more than 200 people have died trying to scale it, but never before has anyone studied these deaths with such a collaborative or fine-tooth approach," said University of Toronto Mississauga Physics professor Kent Moore, a co-author on the report. "We now know with much more certainty what factors play a major role "“ and which factors do not."
Paul Firth, of Massachusetts General Hospital, lead the team of researchers who studied 212 reported deaths on the world's highest mountain between 1921 and 2006.
In climbers who reached above 8,000 meters (26,000 feet), researchers noted cognitive impairment and cerebral oedema (swelling of the brain) were often present, whereas pulmonary oedema (lung problems) was not.
Many deaths occurred above 26,000 feet in an area dubbed "the dead zone," particularly among people who already reached the summit and were climbing back down.
The study showed that 1.3 percent of mountaineers who climbed above their Everest base camp died.
"Of the guys who died up at 8,000 meters (26,000 feet), a large number of them were developing neurological symptoms. In other words, they were getting confused, comatose or they were having a loss of coordination," said Firth, whose findings appear in the British Medical Journal.
Factors most associated with the risk of death were excessive fatigue, a tendency to fall behind other climbers and arriving at the summit later in the day.
"Nobody was attacked by any Yeti or anything else," Firth said, referring to the "abominable snowman" of legend.
Firth said he had expected to see a bigger relation between lung problems and reported deaths.
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