It’s been a week for strange Everest records. On Monday came the news that Climber Rod Baber had become the first man to make a mobile phone call from the highest point on earth.

Now, British doctors have set a record for taking arterial blood samples at 8,400m, on the Everest Balcony, near the summit. We think one of these records will be more beneficial to mankind in the long run. You decide which.

The Caudwell Xtreme Everest team also set up the highest medical laboratory in the world on the mountain’s South Col, 8,000m up. In between setting various medical firsts, they have also put ten of their team on the summit.

The expedition, set up by Dr Mike Grocott, is on the mountain to study the effects of hypoxia – low oxygen levels in the blood – on the human body. Grocott’s team hopes this will give useful information for the future treatment of patients, particularly in intensive care units.

Dr Grocott and climbing leader Dr Sundeep Dhillon summited on Thursday, along with Chris Imray, Nigel Hart, Dan Martin and Dave Rasmussen. A further team consisting of Michael Brown, Roger McMorrow, Jeremy Windsor and Mick O’Dwyer reached the top today.

As well as the doctors, 200 members of the public are involved in the experiment, trekking to base camp at 5,300m. The Caudwell Xtreme Everest organisers are also staking a claim to the largest ever human biology experiment into high-altitude conditions. The participants, who have all paid for their trek to the camp, are keeping daily medical diaries and undergoing scientific testing.

Dr Grocott, expedition leader, said: “Reaching the summit was the culmination of four years of extensive planning and determination to improve the medical world’s understanding of hypoxia.

“We know that 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.

“The data gathered from the trekkers, and from the climbers high on the mountain will, we hope, prove to be a valuable key to our understanding of how healthy individuals adapt to low oxygen.”

He said people with acute respiratory distress syndrome, cystic fibrosis, emphysema and septic shock and ‘blue babies’ could all benefit from the experiments.

He continued: “Although it is possible to simulate low oxygen levels in specially designed, low pressure chambers, studies are very expensive and can produce variable results. Also, the experience for the subjects involved can be unpleasant. It’s the quest for original and accurate results from the field that has inspired us.”

The expedition cost £2m, funded by donations from individuals and companies.