British doctors scaling Mount Everest have measured the lowest human blood oxygen levels ever recorded, according to findings published Wednesday.
The study in the New England Journal of Medicine's January 8 issue could help critical care doctors re-evaluate treatment for long-term patients suffering from respiratory distress syndromes, cystic fibrosis, emphysema, and other serious illnesses, many of which force their hosts to adapt to low oxygen levels in the blood.
The blood samples were taken just below the summit of Everest, at 8,400 meters (27,700 feet) above sea level, by the Caudwell Xtreme Everest team on an expedition led by University College London (UCL) doctors.
Four team members unzipped their down suits and drew samples from the femoral artery in the groin, and the blood was quickly brought down and analyzed in a science laboratory set up in the team's camp at 6,400 meters (21,100 feet), the study said.
The team intended to take the samples on Everest's 8,848-meter (29,029-foot) summit but severe conditions including temperature at minus 25 degrees Celsius (minus 13 Fahrenheit) and winds above 20 knots forced them to a slightly lower elevation.
"By observing healthy individuals at high altitude where oxygen is scarce, we can learn about physiological changes that can improve critical care at the hospital bedside, because low oxygen levels are an almost universal problem in critical care," UCL doctor and expedition leader Mike Grocott said.
"These extraordinary low levels of oxygen found in high-altitude climbers may cause doctors looking after critically ill patients to revaluate treatment goals in some patients who have been ill for some time and might have adapted to low levels of oxygen in the blood."
The study established what had long been suspected -- that high-altitude mountaineers have incredibly low blood oxygen levels which at sea level would only be seen in people close to death.
The average arterial oxygen level among team members sampled was 3.28 kilopascals (kPa) drastically lower than the normal measurement of 12 to 14 kPa. People who measure below eight kPa are considered critically ill.
The study's authors said they believed an accumulation of fluid in the lungs as a result of high altitude may have contributed to the low oxygen levels.
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AFP 072047 GMT 01 09
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