Caudwell Xtreme Everest - Exploring Human Physiology At Extreme Altitude
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NEWS: 6th Apr 2007
 
Medical Research Expeditions: 1960, 1981, 2007

By Dr Jim Milledge

We arrived here at Everest Base Camp yesterday and I am writing this in a comfortable tent with a view of the Ice Fall one way and of Pumori the other. The last time I was here was in 1981 when I was a member of John West?s American Research Expedition to Everest (AMREE). It was very nostalgic to walk up through the villages of Solo Khumbu though the increase in hotels/lodges was amazing. I was pleased that this development was really in good taste and that in this new building they had kept a distinctive Sherpa style. The increase in prosperity seems to have been absorbed without losing the Sherpa welcome and courtesy.

My first visit to this region was as part of the ?Silver Hut? Expedition in 1960 when we set up our winter station, the silver hut, at an altitude of 5800m at the upper end of the Mingbo Glacier behind Ama Dablam. That expedition lasted for 9 months and included a hunt for the Yeti in the first phase, a study of the physiology of acclimatization in the winter and more physiology in the Spring during an attempt on Makalu. The physiology was carried out on about 6-8 subjects, members of the expedition using classical methods. For instance to measure oxygen and carbon dioxide in expired gas we could only use a chemical method (the Lloyd-Haldane apparatus), very tedious!

AMREE was a sort of ?Son of Silver Hut? We were interested in the same problems of acclimatization and performance at altitude. We had the latest technology of the time such as oxygen and CO2 analyzers but, of course no computers. We made the first measurements of barometric pressure on the summit of Everest and collected gas samples from the depth of the lung (alveolar samples). This was on only one subject but gave important information as to the physiology of a man on the summit and has not been repeated in the 26 years since then. Again the number of subjects for our other projects, carried out at Base Camp or in the Western Cwm, was about 6-12.

This Caudwell Xtreme Everest Expedition could be seen as the Grandson of Silver Hut and Son of AMREE. However, in size and ambition it dwarfs then both. We are still doing the classical physiology of exercise performance but now with online computer controlled protocols. We hope to put in place the last unknown bit of data about arterial blood gases on a number of subjects on the summit The breadth of projects has increased, so there are studies of genetics in relation to altitude performance and illness. Also technology has moved on incredibly. There are over 30 lap-top computers devoted to science projects (not to mention personal ones), the latest camera for taking detailed photos of the retina of the eye, Echocardiographs to measure the pulmonary artery pressure, near infra-red spectrograph to measure the oxygenation of the brain and ultra-sound equipment to measure the blood flow to the brain. None of these were available to us in 1981 far less in 1960.

It is an immense privilege and good fortune for me to be able to be involved with this third great medical expedition to this wonderful part of the Himalaya.

By Dr Jim Milledge