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    Causes Of Death On Mount Everest Explored - And It's Not Avalanches Or Ice
    By News Staff | December 9th 2008 02:00 AM | 5 comments | Print | E-mail | Track Comments
    Everyone knows mountaineering can be dangerous and climbing Mt. Everest more dangerous than most. Counterintuitively, most deaths occur during the descent, in the so-called 'Death Zone' just above 8,000 meters. But why deaths happen hadn't really been explored until now. An international research team has conducted the first detailed analysis of deaths during expeditions to the summit of Mt. Everest. They identified factors that appear to be associated with a greater risk of death, particularly symptoms of high-altitude cerebral edema and published their results in the British Medical Journal. "We know that climbing Everest is dangerous, but exactly how and why people have died had not been studied," says Paul Firth, MB, ChB, of the MGH Department of Anesthesia, who led the study "It had been assumed that avalanches and falling ice – particularly in the Khumbu Icefall on the Nepal route – were the leading causes of death and that high-altitude pulmonary edema would be a common problem at such extreme altitude. But our results do not support either assumption." Thousands of climbers have attempted to reach the summit of 8,850-meter (29,000-foot) Mount Everest since the 1920s. In order to examine the circumstances surrounding all deaths on Everest expeditions, the research team – which included investigators from three British hospitals and the University of Toronto – reviewed available expedition records including the Himalayan Database, a compilation of information from all expeditions to 300 major peaks in the world's highest range. Of a total of reported 212 deaths on Everest from 1921 to 2006, 192 occurred above Base Camp, the last encampment before technical (roped) climbing begins. Firth and three physician co-authors – all experienced Himalayan mountaineers with expertise in managing high-altitude illness – reviewed records for all deaths and classified them according to available information. More detailed analysis was conducted on deaths occurring above 8,000 meters during the past 25 years. Deaths were categorized as traumatic, from falls or external hazards such as avalanches; nontraumatic, from high-altitude illness, hypothermia or other medical causes; or as disappearances. Expedition participants were classified as either 'climbers,' individuals from outside the Himalayan region, or 'sherpas' – high-altitude porters, most of them ethnic Sherpas or Tibetans, hired to transport equipment and otherwise assist the climbers. The overall mortality rate for Everest mountaineers during the entire 86-year period was 1.3 percent; the rate among climbers was 1.6 percent and the rate among sherpas was 1.1 percent. During the past 25 years, a period during which a greater percentage of moutaineers climbed above 8,000 meters, the death rate for non-Himalayan climbers descending via the longer Tibetan northeast ridge was 3.4 percent, while on the shorter Nepal route it was 2.5 percent. 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. Many of those who died developed symptoms such as confusion, a loss of physical coordination and unconsciousness, which suggest high-altitude cerebral edema, a swelling of the brain that results from leakage of cerebral blood vessels. Symptoms of high-altitude pulmonary edema, which is involved in most high-altitude-related deaths, were suprisingly rare. "High-altitude cerebral edema symptoms were common among those that died, but signs of pulmonary edema, or excessive fluid in the lungs, were unusual" Firth says. "We also were surprised at how few people died due to avalanches and ice falls in recent years – those usually happen at lower altitudes, and overwhelmingly people died during summit bids above 8,000 feet – and that during descents, the mortality rate for climbers was six time that of sherpas." While the reduced mortality rate among sherpas during descent suggests that taking time to acclimatize to high altitude could improve climber survival, Firth notes that many other factors may be involved. "Most of the sherpas are born and live their lives at high altitudes, and the competitive process for expedition employment probably selects those who are best adapted to and most skilled for the work. So the ability of lowlanders to acclimate to these very high altitudes needs further investigation." During a 2004 Norwegian-American expedition from the north side of Everest led by Firth, equipment problems led the team to turn around at 8,300 meters, return to 7,900 meters and pool their oxygen supply. Half of the team successfully re-attempted the summit and returned safely, including Randi Skuag, the first Norwegian woman to climb Everest. Seven other climbers from other teams that year were not so fortunate – all dying above 8,000 meters, most while descending from the summit. "The majority of those who have died on Everest were in the prime of their lives, with families and friends left bereft," stresses Firth, who is an instructor in Anaesthesia at Harvard Medical School. "Mountaineering is for fun; it's not worth dying or leaving others there to die. Appropriate caution is the hallmark of the elite mountaineer – the mountain will always be there next year."

    Comments

    A nice analylsis of Everest mountain climbing mortality,

    What is the effect of the clusters of climbing deaths on the analysis, such as when a group of climbers are killed in one fall, or when climbers are fatally trapped at high altitude in a storm?

    The experience and fitness of sherpas is somewhat obvious with respect to analysis results; however, there have been numerous discussions of technical expertise of expedition leaders and fitness of expedition participants including the commercialization of Mt Everest climbs more recently. Therefore, is there a trend toward more deaths possibly related to cerebral edema earlier or more recently in the study time frame 1920's to 2006, or not?

    What is the relationship of above-base-camp acclimitization timeframes to cerebral edema related deaths?

    Excellent post, and I would like to add the following. A successful Mount Everest summit has always been considered one of the ultimate forms of achievement. Even though K2 is a much harder mountain to climb in every respect, most of the general public does not know this. But almost all people in developed countries have heard of Mount Everest and can relate to a Mount Everest summit as one of the ultimate forms of achievement. Most deaths occur during the descent simply because you are very tired and the adrenaline rush has decreased. A lot of data was given in the British Medical Journal article and the take home is that yes indeed Everest is dangerous, but the dangers have been reduced in recent years. Today expedition companies provide logistic support, Sherpas, guides, stringent health and physical condition requirements and more. But make no mistake about it, a summit attempt on Mount Everest should never be looked at as an expedition vacation. It is an attempt at one of the ultimate achievements available to man and should be treated as such.

    Greatest achievement? I think not. Perhaps the greatest risk of death, and the definitely one of the most stupid things a human being can do. I do not know what inspires people to risk their lives by doing this. People who have family and especially children at home to take care of are unfit parents. Period. I equate the innate drive to summit these peaks with the innate drive people have to abuse their bodies with hard drugs. The risks are basically the same. Some survive and enjoy the high, but many die in the process. Either way it's a death wish. Just being realistic.

    Something the novice low land climber or the general public does not consider is, upon reaching the summit of any significant summit you are only "half way done". The cause of most of the deaths outside of a confirmed avalance or fall is intelligent speculation as many of the bodies still occupy places along the climb that must be encountered on the way up and consequently on the descent. These people are prepared and well trained for the most part as several tour "leaders" with vast experience on 8000m mountains have lost their lives. Hypoxia is the obvious contender leading to death, this is a harsh place referred to as the "dead zone", anywhere above 24,000ft, the oxygen content @ 8000m is about 1/4 of that @ sea level and many of these Professionals climb sans oxygen. These folks do acclimatize for up to two months during their endeavor, and often spend much of the entire year climbing elsewhere preparing for Everest and other challenges.

    statistic of life and death... what percentage of those who try succeed in their quest for the summit?? how many people have died trying?? what kinds of injuries and impairment have climbers suffered as a result of their attempts to reach the top of the world's highest mountain??