MICHAEL WARD The Contribution ofMedical Science to the First Ascent ofEverest The Solution of the High-Altitude Problem (Plates 30-33) This article should be read in conjunction with 'The Exploration of the Nepalese Side of Everest' by Michael Ward, which appeared in Af97, 2I3­ 221, L992/93. The two articles, taken together, cover a progression ofsignifi­ cant events, both scientific and topographical, which took place between 1945 and the first ascent ofEverest in L 953. The linkage is set out in Appendix 3 on pages 50-5r. The opening of Nepal in 1949, and the confirmation of a possible new route up Everest by the 1951 Reconnaissance expedition, gave a powerful impetus to high-altitude studies; for despite the best efforts of medical scientists and mountaineers in the 1920S and 1930S, the final thousand feet of the mountain remained unclimbed. Between 1921 and 1938 about 25 people had reached a height of 27,000ft and above, eight climbing to 28,000ft, both with and without supplementary oxygen. At these heights, ascents without using oxy­ gen are at the limit of what is medically and physiologically possible, yet it was still unclear whether the use of oxygen was as effective as acclimatisation in generating a performance adequate to reach the summit. It was the solution of this problem by Dr Griffith Pugh and his colleagues at the Medical Research Council in London and on the Cho Oyu expedition in 1952 that was to be a key factor in the first ascent of Everest. The use of supplementary oxygen before the Second World War Some of the best respiratory physiologists had helped early Everest expedi­ tions. Haldane, Barcroft and others had been adamant that supplementary oxygen should be used for the ascent. Their opinion was influenced by the death of two Frenchmen in 1875 at 28,000ft, an altitude to which they had ascended by balloon without supplementary oxygen. Tissandier, the third member of the party, only just survived. However, in the late 19th century, Conway had climbed to 24,60oft on Pioneer Peak in the Karakoram without the use of oxygen, and Clinton Dent in 1893 I had stated his conviction that Everest (which he called Gaurisankar) could be climbed without supple­ mentary oxygen and Alexander Kellas in 1920 had reached the same con­ c1usion.~ Medical scientists who had underestimated the effects of acclimatisation EVEREST 1953 were amazed when mountaineers on early Everest expeditions in the 1920S and 30S reached heights of 28,000ft without supplementary oxygen. In fact oxygen was used on these expeditions, but it did not give as much benefit as it should have done and, confusingly, some mountaineers seemed to climb as fast (or faster) without supplementary oxygen as those who were using it. However, Finch (later Professor at Imperial College, London) reached 27,000ft on Everest in 1922 using supplementary oxygen. He was convinced of its effectiveness and noted that sleeping oxygen combated fatigue and maintained the climber's physical condition. Unfortunately he was not chosen for the 1924 expedition on which four men, climbing without supplementary oxygen, reached 28,000ft; at this height, Mallory and Irvine, using open­ circuit oxygen, were last seen by Odell. On this expedition, too, Somervell, a surgeon, was able to measure the amount of oxygen in the depth of the lungs at the highest altitude yet attained. On expeditions in the 1930S mountaineers and scientists made many contri­ butions. In 1933 Greene developed a very efficient open-circuit apparatus and also advocated the use of oxygen in the treatment of frostbite. This comprised a 500 litre cylinder with a capacity fot delivering up to 3 litres per minute and it weighed I2lb 120Z. With hindsight, neither the flow rate nor the amount of oxygen would have been adequate to provide a sufficient boost to perform­ ance for long enough. The apparatus was never used on the mountain because, after the two attempts without supplementary oxygen (which had priority) had failed at 28,000ft, the weather became so bad that the party retreated to Base Camp. Unfortunately the slopes of the North Col then became so dangerous from avalanches that no further attempt was possible. 3 Warren, the medical officer in 1935, 1936 and 1938, was initially very keen on the closed-circuit apparatus, and in 1937 he tested it in the European Alps, on the Matterhorn and Wellenkuppe. Because of bad weather the 1936 expedition only reached about 23,000ft, but in 1938 Warren and Lloyd used the closed­ circuit apparatus high on the mountain. As a result of technical and practical difficulties in the field, Warren, who had initially been keen on the closed­ circuit apparatus, changed his mind and became an advocate of the open circuit,4 as did Lloyd. Tilman, who led the 1938 expedition, had little regard for oxygen, nor indeed for any other kinds of scientific investigation on expeditions, since his preference was for keeping things as small and simple as possible. In 1938 he had compromised these principles by taking along, under protest, four sets of oxygen. Oxygen sets for use on Everest, developed in connection with high­ altitude flying in the Second World War, were discussed by Roxburgh of the Institute of Aviation Medicine in the 1947 Geographical ]ownal.5 But there was still, by 1951, no consistent evidence that supplementary oxygen had given a significant boost to performance on the mountain. Two types of oxygen apparatus had been developed for mountaineers to use at extreme altitude. In the open-circuit apparatus oxygen is added at different flow rates to the air that the mountaineer is breathing. The 'altitude in the depths of the lungs' is determined by the flow rate of the oxygen, enabling the mountaineer to be at a 'lower' altitude than that at which he is actually THE CONTRIBUTION OF MEDICAL SCIENCE " 39 climbing; this should enable him to climb faster. The exhaled breath is vented to the atmosphere. The apparatus is simple and rugged but a considerable number of oxygen cylinders have to be carried by the climber. With the closed-circuit apparatus the climber breathes pure oxygen from the cylinder carried on his back, the exhaled air is passed over a soda-lime canister, CO 2 is absorbed and the oxygen is recycled, hence the term 'closed­ circuit'. Obviously a lower flow rate of oxygen is used than is necessary in the open-circuit apparatus. The mountaineer is at or near sea-level in the depths of the lungs and this gives him a greater boost, but the apparatus is heavy and, being more complicated than the open-circuit, it is more likely to break down. If it does so, sudden exposure to extreme altitude can cause severe problems, since the mountaineer, at one moment at 'sea-level', is suddenly exposed to the extreme altitude at which he is actually climbing. This occurred to Bourdillon at 26,000ft on the South Col in 1953. Another important observation at altitude was made by Sir Bryan Mathews FRS (later Director of the Institute of Aviation Medicine at Farnborough and Professor of Physiology at Cambridge) who highlighted the point that heat loss could occur through the lungs as a result of increased respiration, and that this could lead to general body cooling and frostbite. 6 The part played by dehydration in deterioration at extreme altitude was later discussed at an informal meeting at Farnborough in 1947, and the suggestion was made by Rudolf Peters, Professor of Biochemistry at Oxford, that this was due in part to the high rate of breathing.7 Throughout the 1920S and 1930S opinion on the use of supplementary oxygen at altitude was divided. In general. the doctors and scientists favoured its use, whilst others thought that reliance could be placed on acclimatisation alone. A third group, of which Tilman was one, were the purists who disap­ .proved of the use of supplementary oxygen on principle. Operation Everest I in the USA (1946) In 1946 Charles Houston took part in a landmark experiment in high-altitude studies called 'Operation Everest 1'.8,9 A flight surgeon in the US Navy from 1941 to 1946, he had been a member of the successful British-American party that made the first ascent of Nanda Devi in 1936 and had led the 1938 American attempt on K2. With this background he had been working in altitude research and, in 1946, he and the distinguished respiratory phys­ iologist Richard Riley and others conducted 'Operation Everest I' in a decom­ pression chamber at Pensacola Air Base, Florida. In this five-week study, four volunteers were gradually decompressed to a simulated altitude equal to the 'summit of Mount Everest'. However, they used an aneroid barometer calib­ rated by the International Standard Atmosphere table, and the reading actually corresponded to the barometric pressure found at 30,000ft rather than 29,028ft. Two of the four volunteers managed to exercise on a stationary bicycle ergometer for 20 minutes 'on the summit of Everest' without supple­ mentary oxygen, thus producing the first solid evidence that such efforts were possible at such a height. EVEREST 1953 On the ground, however, mountaineers without supplementary oxygen at 28,000ft were climbing so slowly that, even from a camp at 27,000ft, it seemed unlikely that they could reach the summit of the mountain and return without an enforced bivouac. Although the technical climbing difficulties of the last 1000ft on Everest did not appear insuperable, the prevailing weather conditions and the lack of modern protective clothing made it a dangerous undertaking. Climbers at this altitude in the pre-war period had suffered from hallucinations, some had died from cold injury, one porter had developed a hemiplegia (stroke), dehydration was marked, fatigue overwhelming and loss of weight extreme.