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Archive for May 21st, 2012

What is the Death Zone?

Posted on May 21st, 2012 by Admin

Another in our series on the science of the expedition, Dr. Jim McEachen, Mayo Clinic aerospace medicine fellow provides background [Editor's note: this was written before the most recent deaths] 

In 1998, the popular PBS series Nova reported an ominous piece of data.  For every six successful summits on Everest, one person will die.  The show was following up on a tragic event that occurred two years prior. In one day, eight climbers died in the so-called ‘death zone’ on Everest.  The term ‘death zone’ is often used in reference to an altitude above 26,000 feet beyond which many researchers believe human life can no longer adequately acclimatize on its own to.  At 17,600 feet (Base Camp), the partial pressure of oxygen (pO2) is approximately half of its value at sea level.  At 29,000 feet (Everest Summit), the pO2 level decreases to approximately one third of its sea-level value. The ability of individuals to survive in such extreme conditions is a reflection of both their short and long term hypoxic compensatory mechanisms.  As an aside, the validity of the term ‘death zone’ does remain in dispute among some researchers who note select cohorts of individuals have survived for extended periods of time under analogous extreme hypoxic conditions.

Extreme hypoxic states are not limited to the mountainside.  They are also a matter of significant concern to both the airline and space industries.  For example, fighter and reconnaissance aircraft which can fly in excess of 50,000 feet must incorporate specialized environmental control systems and life support equipment to ensure the ability of pilots and aircrew to function under such extreme conditions.  Of particular interest, above Armstrong’s Line (63,000 feet) exposed bodily liquids could actually boil in the absence of protective life support equipment.  Such challenges do not diminish our desire to explore, but rather provide the basis for understanding and future innovation.  And so we climb further…

Tragic news from Everest, but Team Begins Ascent

Posted on May 21st, 2012 by Admin

At this writing the deaths of four climbers from various expeditions have been confirmed and a fifth climber remains missing on the upper levels of Mount Everest. The French news service lists the climbers as originating from China, Canada, South Korea and Germany.  The news stories attribute the deaths to complications from altitude sickness and the delayed ascents of many of the teams due to the jam of climbers on the mountain over the weekend.

The sad news comes as the North Face/National Geographic team sets out on its ascent. National Geographic confirmed this morning that the team led by Conrad Anker left base camp this morning in hopes of summiting on the 25th. The North Face confirms that the team is now at camp 2 on the mountain, the first stop on the way up.

The deaths occurred in what has come to be called the "death zone" - the highest section of the mountain where humans cannot live very long without oxygen. We'll have a further explanation of the dangers of this location in our next post.

Bringing it to the patient

Posted on May 21st, 2012 by Admin