A group of British doctors who climbed just short of the top of Mount Everest have measured the lowest blood oxygen levels ever recorded.
The discovery, published in the latest issue of the New England Journal of Medicine, could lead to improved critical care for patients suffering from such diseases as emphysema.
The doctors from University College London drew samples of their own blood at 84-hundred meters above sea level. They were just under the summit of Mount Everest in Nepal, the world's highest mountain.
Their blood oxygen level was about nine points below normal levels and five points lower than what doctors measure in critically-ill patients.