Mountain sickness.

Acute mountain sickness carries with it serious health and economic costs. In their pursuit of the mechanisms that produce acute mountain sickness, researchers have overlooked the existence of a possible screening test, a test based on individual variation in cerebral oxygen exchange at sea level. In this paper, I highlight the mathematical link between cerebral oxygen exchange at sea level - this is reflected in the magnitude of the oxygen extraction coefficient - and a change in brain blood flow at altitude; this link has been overlooked. A lower oxygen extraction coefficient at sea level can act - at altitude - to reduce the capacity of the intracranial compartment to accommodate brain swelling, exacerbate increases in cell volume, promote the stimulation of angiogenesis, and further cerebral edema, each of which may contribute to acute mountain sickness. In retrospect, it seems obvious that the initial state of cerebral oxygen exchange will impact the cerebral circulatory response to subsequent hypoxia. This deceptively simple notion offers us an opportunity to identify beforehand those people likely to develop acute mountain sickness when they travel to altitude.

Altitude Sickness↗

PubMed2003

Everest 1953, first ascent: a clinical record.

No mountaineering expedition to Mt. Everest mounted by the Royal Geographical Society and the Alpine Club from 1921 onward reached the summit, despite the mountaineering difficulties being of a similar order to those found on the ascent of Mont Blanc (15,800 ft), the highest peak in Europe, which was first climbed in 1786. The reason for their lack of success was their inability to solve the medical and physiological problems imposed by the altitude and cold of the last thousand feet, between 28,000 and 29,028 ft. It was the solution of these problems by the Medical Research Council, backed by the Royal Society, in London, in early 1951 through 1952 that made the breakthrough leading to success in 1953. During the first ascent, in order to assess the effectiveness of these solutions, accounts were taken immediately on their descent from every climber who had been as high as the South Col (26,000 ft) or higher, including the two who had reached the summit (29,028 ft). These accounts provided a unique record and illustrated, for the first time in 30 years of Everest expeditions, how the use of adequate flow rates of supplementary oxygen when climbing, adequate supplementary oxygen when sleeping, adequate daily fluid intake, and adequate protection from the cold could transform the performance of climbers at extreme altitude from "sick men climbing in a dream" to those capable of overcoming all climatic and mountaineering obstacles. None of these advantages had been available to mountaineers of British parties of the 1920s and 1930s, nor to the Swiss expeditions in the spring and autumn of 1952, with the result that none of them was successful in reaching the summit.

Altitude Sickness↗