Medicine at the top of the world
Medicine at the top of the world
Jan 4th 2007
From The Economist print edition
An expedition to Everest may improve the chances of people in intensive care
LYING in an intensive-care ward is a world away from climbing Everest, but a connection will be drawn this spring when 45 scientists and 208 volunteers tackle the mountain to bring back information about oxygen deprivation. The reason they are going is that hypoxia (a lack of oxygen in cells, which can lead to death) is the one thing that links practically all patients in intensive-care wards—and there is no better place to study it than in the thin air of the world's highest mountain.
AP How they used to do it
Hypoxia in hospital patients has various causes, from circulation problems to metabolism difficulties. It requires invasive and aggressive treatment. The patient is artificially ventilated, a procedure that can cause inflammation, lung damage and infection. Strong drugs similar to adrenaline are also used, to increase the heart's performance and thus get more oxygen around the body. That risks damaging the heart. So a more elegant way to prevent hypoxia in seriously ill people would be most welcome.
The Xtreme Everest expedition, organised by University College London, hopes to shed light on the problem by testing the theory that a person's ability to handle hypoxia is genetically determined. Although that will not help directly, except perhaps to identify who is likely to need the most powerful (but damaging) remedies and who can be given milder treatment, finding the genes involved will illuminate the relevant biochemistry and thus, with luck, lead to better treatments.
Mike Grocott, the expedition's leader, says that research published a few years ago by his colleague Hugh Montgomery suggests genetic variability may, indeed, be involved. He hopes Xtreme Everest will confirm Dr Montgomery's work by showing that how well a person deals with hypoxia is related to the efficiency with which his cells utilise oxygen—and that this, in turn, is genetically determined.
Although taking more than 250 people up Mount Everest to find the right conditions may, indeed, seem extreme, Dr Grocott says it was the only way. Carrying out experiments on people in intensive care is made difficult by the small numbers of patients on any one ward, the huge variety of conditions from which they suffer and the tricky matter of gaining consent from an unconscious individual. An obvious alternative—hiring all the low-pressure chambers in Britain for several months—would not actually provide sufficient capacity, even if enough volunteers could be found to sit in the chambers.
For an expedition to Everest, though, finding volunteers was not a problem. Lots had to be turned away. Those chosen, who are aged between 18 and 73, will undergo a day of tests at sea level, to establish their metabolic baselines and have their DNA sampled. They will then head for Nepal, armed with masses of equipment to set up mobile laboratories in Kathmandu (altitude 1,400 metres, or 4,600 feet), at 3,400 metres, at 4,200 metres and at the base camp from which expeditions to the summit usually set off (5,300 metres). At this altitude the atmospheric pressure is half that at sea level, and thus delivers half the amount of oxygen per lungful.
The lay volunteers will stop here, but a team of 16 climber-scientists will go on to the south col (just under 8,000 metres) and ten will continue to the summit, at an altitude of 8,848 metres, where the air pressure is just a third of its sea-level value. Once there, they will take the first ever blood samples on Everest's summit.