Xtreme scientists conquer Everest to find lowest blood oxygen levels

A team of mountaineering doctors from UCL have reported the lowest human blood oxygen levels ever recorded.

The Caudwell Xtreme Everest expedition climbed close to the summit of Mount Everest and at 8,400 metres above sea-level, four team members stripped in -25°C conditions so that blood could be drawn from the femoral artery in the groin. The blood samples were then rushed back down the mountain and analysed at a laboratory set up at the team’s camp at 6,400 metres on Everest.
Xtreme Everest expedition leader Dr Mike Grocott from UCL explained the purpose of the climb:  “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 beside, because low oxygen levels are an almost universal problem in critical care.”
They found that the average arterial oxygen level was 3.28 kilopascals (kPa) and the lowest value was 2.55 kPa; the normal value in humans is 12-14 kPa and patients with a level below 8 kPa are considered critically ill. In the case of the climbers, the doctors suspect that an accumulation of fluid in the lungs caused by the high altitude may have contributed to the low oxygen levels in the blood.
The team hope that their ongoing research will eventually lead to better treatments for patients with acute respiratory distress syndrome (ARDS), cystic fibrosis, emphysema, septic shock, ‘blue baby’ syndrome and other critical illnesses.

By Leila Sattary