HIGH ALTITUDE AND OXYGEN

N. E. ODELL

AT THE British Association Centenary Meeting held in -London in September last, Professor J. Barcroft, F.R.S., addressed section I on " The Limits placed by Altitude to Physical Exercise ", which was followed by a discussion of the subject, to which both Dr. Raymond Greene, who was one of the party to reach the summit of Kamet last year, and myself, who took part in the Mount Everest Expedition of 1924, contributed. As nothing about this problem has appeared in The Himalayan Journal as yet, it may be of interest to give a summary of the views expressed.

Professor Barcroft pointed out that the work of Italian researchers had shown that man can live at an atmospheric pressure of about 110 mm., if he breathes, not air, but oxygen. At that pressure he can do little or no work. More recent researches by Barcroft, Douglas Kendal and Margaria have, however, shown that at 170 mm. pressure, breathing oxygen, man can step up a thousand feet in an hour. As the test consisted of stepping on to a box, it was incidental that he stepped down as often as he stepped up. One hundred and seventy millimetres is a much lower pressure than that at the top of Everest. It, follows therefore that, given a supply of oxygen into the respiratory passages, the feat of climbing at the highest altitudes of the earth's surface is not impossible, and that, apart from unknown difficulties of terrain, the problem of climbing Mount Everest is less one for the mountaineer than one for the engineer. Not the engineer in general : but a particular sort of engineer, one who specializes in the apparatus of respiration, such, for instance, as the diving engineer, or those of the technical chemical defence departments of the National Armee.

The amount of oxygen necessary is about a litre and a half per minute. If an ascent of five thousand feet is to be made in five hours, the oxygen actually absorbed by the climber would be 450 litres. Suppose he breathed half that amount on the descent, some seven hundred litres would be required, or say thirty cubic feet, for the whole journey. The problem then may be subdivided thus :—

1. How is man to carry 30 cubic feet of oxygen ?
2. If he ' re-breathes ' it, how is he to get rid of the carbonic acid ?
3. How is he to cope with the incidental difficulties proper to the use of the apparatus, such as the occurrence of water vapour, which freezes in inconvenient places ?
4. How much margin over and above the theoretical quantity is necessary for safety ?

Seven hundred litres weigh approximately a kilogram, so that the weight of the oxygen itself is trifling, but the weight of an ordinary cylinder which would carry 30 cubic feet of compressed gas is too great. What therefore are the lightest cylinders into which it can be compressed ? Were the problem one for providing a supply of air for a diver or a respirator for a soldier, a competent authority would sit down to face it on a basis of exhaustive experiment and extended drill. In the end, said Professor Barcroft, he had little doubt that the problem would be solved with less expenditure than is entailed in the equipment and expenses of successive expeditions to the Himalaya— expeditions which not only cost money but a toll of valuable lives.

I have been unable to get hold of a copy of Dr. Raymond Greene's contribution to the discussion, but an article which he sent to Nature and which was published in the issue of that paper for November 28th, 1931, gives the substance of his earlier discussion. In that article Dr. Greene gives the views of both the oxygen school and the no-oxygen school. He sums up by saying : "If, then, the oxygen school believes in the usefulness of oxygen for high climbers, whether acclimatized or not, and the no-oxygen school believes in its usefulness for the unacclimatized, a method of attack in conformity with both points of view appears at first sight to be obvious. It should be possible to eliminate the necessity for acclimatization by using oxygen from a low level on the mountain and climbing it at alpine speed. But here two great problems present themselves. It is very difficult to construct an apparatus which will without waste deliver the required quantity of oxygen while the climber is eating and sleeping and it is impossible at the moment to find an apparatus which can be trusted never to go wrong. The failure of his oxygen apparatus near the top of Everest would mean death to an unacclimatized mountaineer ".

My own contribution to the discussion was as follows :

Following the second expedition to Mount Everest, which was the first actual assault above 23,000 feet on the main summit, opinions differed as to the actual value of an artificial supply of oxygen. Finch and Geofirey Bruce had reached 27,200 feet using an oxygen apparatus all the way from 21,000 feet. But Mallory's party of four climbers had also attained almost an equivalent altitude, namely 26,900 feet, entirely without oxygen equipment, and relying upon their own inherent powers of acclimatization.

The third expedition of 1924 was equipped with apparatus of an improved kind, including three cylinders of a specially light alloy (" Vibrac " steel), and a total capacity of 1605 litres, or about 57 cubic feet, of oxygen. This amount at the prescribed continuous consumption of two litres per minute was to provide for a thirteen hours' climb, ascent and descent. The total weight was about 33 lbs. ; but it was later reduced to 22 lbs. by discarding one cylinder and modifying the breathing apparatus.

Owing to various defects in the apparatus, to some extent consequent upon rough handling on the outward journey across Tibet, considerable delay was occasioned by the necessary repair work before a sufficient number of apparatus was available for use on the mountain. In the meantime high camps were pitched and plans laid for attempts on the summit without breathing apparatus. And these very efforts of the climbing party were the means of bringing about a degree of acclimatization never before attained by previous climbers. Geoffrey Bruce, who had depended on oxygen in 1922, now found no perceptible relief when using it. I myself carried on one occasion un apparatus up to 27,000 feet, and as I was getting no benefit at 26,000 feet, I turned off the supply of gas and continued climbing with no noticeably enhanced fatigue. By living at an altitude of not loss than 23,000 feet for eleven days a very high degree of acclimatization had been acquired.

It must not be supposed, as Raymond Greene has suggested, that the failure to find relief or advantage when using oxygen was due to some inherent defect in the apparatus and its supply of oxygen to the lungs¹. On the contrary, every apparatus eventually repaired was in perfect gas-tight condition, and by practice a suitable habit of inhaling from the mouthpiece of the supply-tube had been acquired by the users.

Acclimatization to an altitude of 27,000 feet has been demonstrated, and there seems no valid reason why it should not be possible to over 29,000 feet, or the top of Everest. In their record-making ascent to 28,000 feet and over, without oxygen supply, Norton and Somervell were admittedly reduced to extremely slow upward progress, but it must be remembered that neither of them were fit men at the outset, largely owing to their having taken part in an exhausting rescue expedition not long before. Mallory and Irvine set out on their last tragic climb with breathing apparatus, but we may never know what benefits, if any, they derived from it. In any case, there is nothing to warrant Raymond Greene's recently expressed views that their failure to return was due to a breakdown in the apparatus².

Our general conclusions regarding the use of oxygen were long ago stated in The Fight for Everest, 1925, page 329, wherein it was maintained that for a mountain of exceptional altitude, such as Everest, a future climbing party might advisably be provided with a light form of apparatus supplying sufficient gas for the last few hundred feet of the mountain. It was strongly recommended, however, that such apparatus should be considered an emergency measure only, and acclimatization to the highest altitudes should be resolutely aimed at. In practice such altitudes on Everest would be about 27,000 or 28,000 feet, the height of the highest camp, and one to which carrying parties must ascend, unhampered by the extra individual load of breathing apparatus. For in this connection it should not be forgotten what a high percentage of available porterage can be worn out, as it was on the Mount Everest expeditions, in carrying up the oxygen supply for the summit-climbing parties.

With these considerations in view a lightened and simplified apparatus was devised in 1925, and trials of its suitability for mountain use were made in Snowdonia. The equipment provided for about fifteen cubic feet of gas and its weight was not more than 12 lbs. Thus the load involved becomes a manageable one and from the experience gained thus far it should provide ample oxygen for emergency purposes, if due regard has been given to acclimatization.

The problem of the engineer, as conceived by Professor Barcroft, would, therefore, appear to have been already largely solved by the mountaineer, though not without the earlier advice of the former. Moreover both engineer and physiologist may be reminded that among many mountaineers the opinion prevails that, if Mount Everest and other high Himalayan peaks are worth climbing at all, they should be ascended without such artificial aids as may reduce a sport to a mere laboratory experiment. If however, in the interests of physiology the opportunity should not be missed, where, it may be asked, can this important problem of acclimatization be better studied than under actual mountain conditions ? It would seem to be as important of study as the mere duplication of experiments carried out in the pressure chamber, where it has been shown already that man can survive, when primed with oxygen, at a pressure much below that obtaining at the summit of Mount Everest.

Note by Editor.

To Mr. Odell's and Dr. Greene's contributions to this subject, we may perhaps lie permitted to add some conclusions to be drawn from Paul Bauer's last determined assault on Kangchenjunga. Bauer's party was composed of young men in the fittest possible training before the task was undertaken. It took this party sixty-eight days to reach an altitude of 26,000 feet from Camp VI at 16,800 feet. Acclimatization was forced on them by the supreme difficulty of the actual climbing, so that when they reached 24,000 or 25,000 feet, at which Colonel Norton has said " the difficulties imposed by altitude only begin to be really serious ", acclimatization had been attained to such an extent that no inconvenience was felt and it became possible to advance six hundred feet in an hour at 25,000 feet through deep snow over otherwise easy slopes. No oxygen was necessary nor was its want felt. The possibility of moving at this rate without oxygen would have been ridiculed a few years ago. It was not lack of oxygen that defeated Bauer, but dangerous snow, such as might defeat any other wise man at Alpine altitudes.

That the general conclusions arrived at after the last Everest expedition are sound has been fully borne out by Bauer's recent experience. Acclimatization is possible up to any altitude that has so far been attained ; it cannot be hurried and it appears to be unwise to adopt " rush tactics " until complete acclimatization has been acquired and then only for a short distance. With Bauer himself, probably one of the fittest of the party and the hardest worked, but, I believe, the oldest at thirty-four, it was a near thing. Though fully acclimatized, he almost collapsed from overstrain. Oxygen, even in small quantities as an emergency measure, would surely have been invaluable in his very critical condition during the night spent at Camp X, when he no longer had the strength to continue the descent and almost froze to death.

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