September 24, 2008 In addition to making history and winning Edmund Hillary a permanent place on the New Zealand fiver, the first successful Everest ascent settled a long-running debate in the scientific community about breathing devices. Hillary and Norgay used open-circuit breathing apparatuses, in which a reserve of oxygen is inhaled by the user and exhaled out of the system, and their success secured such systems as the dominant breathing technology for high-altitude climbing. However, in order to treat chronic obstructive pulmonary disease, Smiths Medical and University College London have resurrected the sidelined closed-circuit system for use in oxygen therapy.

Hillary’s first remark after returning from Everest was the John McClane-esque “Well, George, we knocked the bastard off.” It must have been sheer agony to Tom Bourdillon and Charles Evans, who came within 90 meters of the summit just three days before Hillary and Norgay planted the flag. Before being forced to turn back, Bourdilon and Evans positively raced up the mountain – they once covered in 90 minutes what would take Hillary and Tenzing over two hours. The reason for their efficiency was the closed-circuit breathing system they were pioneering, a design created by Bourdilon and his father. Closed-circuit devices, (also known as rebreathers), create a seal over the user’s mouth, retaining the exhaled air, scrubbing it of carbon dioxide, and allowing the user to inhale it again. The rebreathing aspect of Bourdilon’s apparatus worked perfectly, but the hostile Everest conditions eventually proved too much for the device.

Jenny Windsor and Roger McMorrow, mountaineering scientists at UCL, realized that Bourdilon’s research does not have to be anchored to the failed expedition. The strength of closed-circuit breathing devices is their efficiency and portability, due to the lack of cumbersome oxygen tanks. Such traits could greatly improve conditions for patients undergoing oxygen therapy for COPD, a breathing condition affecting 10-15% of smokers and the fourth leading cause of death in the USA. COPD causes the airways to become narrowed, limiting the supply of oxygen to the body. In order to treat the disease, patients need to begin an exercise regimen and receive a steady supply of oxygen-rich air. Since up to 95% of exhaled air from patients undergoing such therapy is oxygen, a system that captures the air and resupplies it to the patient clean of CO2 would be far superior to an open-circuit system.

"We are hoping that this new technology will transform the lives of people living with COPD by allowing them to breathe more easily, exercise and ultimately reduce their dependence on oxygen. It is incredible to think that this breakthrough device is based on a British invention designed to help the first mountaineers reach the top of the world," said Dr Jeremy Russell, head of research and development at Smiths Medical International.

Professor Monty Mythen, Smiths Medical Professor of Anaesthesia at UCL and Director of Research and Development at UCL Hospitals said: "This project is a fantastic example of the success that comes from scientists in industry working closely with clinicians and university academics for patient benefit. Smiths Medical in collaboration with UCL and NHS partners makes a formidable team and I am delighted that the Caudwell Xtreme Everest expedition is beginning to reap rewards for patients."

Note on images: historical images courtesy of Royal Geographical Society (RGS).

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