Great advances in science and medicine are seldom achieved without bold experimentation.

So it is that in pursuit of lifesaving treatment for critically sick children, British scientists will shortly lead a party of kids up through the Himalayas, towards Everest.

Sometimes roped to Sherpas as they ascend up to 13,000ft (4,000m), The Smiths Medical Young Everest Study will test how nine children, aged from 6 to 13, respond to high altitude and low oxygen levels. It is, for obvious reasons, the first test of its kind.

An adult study — the Caudwell Xtreme Everest project — has for some time been planned for the slopes of Everest, involving 200 British volunteers.

Where such tests were previously carried out on mountaineers, the Caudwell study was using a more reflective sample of healthy adults to test the effects of hypoxia — shortage of oxygen in the blood that occurs in acutely ill patients. Around 25 per cent of patients prove unable to cope with hypoxia, and many die as a result.

Monty Mythen, Smiths Medical Professor of Anaethesia and Critical Care at University College London, told The Times: “At sea level you can’t tell who will cope and who won’t. On Everest, if we can understand more about what makes someone a rapid adapter, we may be able to find the switches and adaptors to help the others cope.”

The only problem was, whatever the study might reveal about adults could not safely be applied to children. “Children are not just miniature adults,” he said. “Their bodies function differently.”

The test needed to be replicated with children — the results could prove vital to the treatment of premature babies, babies born with cystic fibrosis and sickle cell disease, and children with congenital lung problems.

But where was he to find a parent willing to allow their child to be taken into a third world country and up to a height where altitude sickness frequently levels the healthiest of men?

The professor decided to inflict the tests on his own four children. Along with his own offspring, four of the professor’s nephews and nieces will shortly head to Kathmandu. Their grandmother is going too, as is Samatha Sonnappa, a respiratory paediatrician, who is taking her own son Mayank, 6.

Professor Mythen will travel ahead to Namche Bazaar, a sherpa station between Tibet and Nepal, to set up a laboratory. The children will be led by his colleague Janet Stocks, Professor of Respiratory Physiology at Great Ormond Street Hospital for Children.

Boarding a small fixed-wing plane, they will fly across the mountains to Lukla, landing on a tiny runway that juts from a precipitous mountainside.

From there they will set off on foot along a lush river valley — “just like anywhere else really, except for the yaks on the pathway,” said Dr Mythen.

After two days they will enter Everest National Park and make a challenging ascent to Namchee, for tests 11,180ft (3,440m) above sea level. Provided that they are still in good health, the children will continue higher, up to Tengboche to plant a flag beneath the towering spire of Everest.

The older children may then venture on to Everest Base Camp, at 17550ft (5,400m), before descending.

“We would not say we are using the children as guinea pigs,” said Professor Mythen. Rather he feels they are being encouraged to put themselves forward, following their father’s own example, as a man who once had a quarter of his blood removed to determine what effect it had on the heart and blood pressure.

“We think we have taken all the risks into consideration,” he said. “We have the right people on hand and the route we have chosen provides a quick way down. As for the apparent risks of taking children to a third world country, they are travelling with paediatric doctors.”

His children are wildly excited about striding to the frontier of medical science and human exploration. Patrick, 13, told The Times: “I have climbed hills in the Lake District but I have never done anything like this.”

The tests they undergo could prove lifesaving, and open up a new frontier of child-testing on Everest. It will also demonstrate the durability of new technology, including a “life vest” that could allow sick children to be monitored in their home rather than in hospital.

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