Career perspective: John B West

Extreme Physiology & Medicine

John B West¹ 

[1] Department of Medicine 0623A, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0623, USA

关键词: Microgravity;    Pulmonary gas exchange;    Distribution of blood flow;    Maximal oxygen uptake;    Hyperventilation;    Extreme hypoxia;   

Others  :  820660
DOI  :  10.1186/2046-7648-1-11

 received in 2012-08-02, accepted in 2012-08-08,  发布年份 2012

【 摘 要 】

I have been fortunate to work in two areas of extreme physiology and medicine: very high altitude and the microgravity of spaceflight. My introduction to high altitude medicine was as a member of Sir Edmund Hillary's Silver Hut Expedition in 1960–1961 when a small group of physiologists spent the winter and spring at an altitude of 5,800 m just south of Mt. Everest. The physiological objective was to obtain a better understanding of the acclimatization process of lowlanders during exposure to a very high altitude for several months. As far as we knew, no one had ever spent so long at such a high altitude before. The success of this expedition prompted me to organize the 1981 American Medical Research Expedition to Everest where the scientific objective was to determine the physiological changes that allow humans to survive in the extreme hypoxia of the highest point on earth. There is good evidence that this altitude is very near the limit of human tolerance to oxygen deprivation. Much novel information was obtained including an extraordinary degree of hyperventilation which reduced the alveolar partial pressure of carbon dioxide (Pco₂) to about 8 mmHg (1.1 kPa) on the summit, and this in turn allowed the alveolar partial pressure of oxygen, PO₂, to be maintained at a viable level of about 35 mmHg (4.7 kPa). The low Pco₂ caused a severe degree of respiratory alkalosis with an arterial pH exceeding 7.7. These were the first physiological measurements to be made on the Everest summit, and essentially, none has been made since. The second extreme environment is microgravity. We carried out an extensive series of measurements on astronauts in the orbiting laboratory known as SpaceLab in the 1990s. Many aspects of pulmonary function are affected by gravity, so it was not surprising that many changes were found. However, overall gas exchange remained efficient. Some of the findings such as an anomalous behavior of inhaled helium and sulfur hexafluoride have still not been explained. Measurements made after astronauts were exposed to 6 months of microgravity in the International Space Station indicate that the function of the lung returns to its preexposure state within a few days.

【 授权许可】

   
2012 West; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

Figure 2.

【 参考文献 】

• [1]Pugh LGCE, Gill MB, Lahiri S, Milledge JS, Ward MP, West JB: Muscular exercise at great altitudes. J Appl Physiol 1964, 19:431-440.
• [2]Milledge JS: The silver hut expedition, 1960–1961. High Alt Med Biol 2010, 11(2):93-101.
• [3]Pugh LGCE: Physiological and medical aspects of the Himalayan scientific and mountaineering expedition, 1960–61. BMJ 1962, 2:621-633.
• [4]West JB: American medical research expedition to Everest. High Alt Med Biol 2010, 11(2):93-101.
• [5]West JB, Lahiri S, Maret KH, Peters RM Jr, Pizzo CJ: Barometric pressures at extreme altitudes on Mt. Everest: physiological significance. J Appl Physiol 1983, 54:1188-1194.
• [6]West JB, Hackett PH, Maret KH, Milledge JS, Peters RM Jr, Pizzo CJ, Winslow RM: Pulmonary gas exchange on the summit of Mount Everest. J Appl Physiol 1983, 55(3):678-687.
• [7]Sutton JR, Reeves JT, Wagner PD, Groves BM, Cymerman A, Malconian MK, Rock PB, Young PM, Walter SD, Houston CS: Operation Everest II: oxygen transport during exercise at extreme simulated altitude. J Appl Physiol 1988, 64:1309-1321.
• [8]Richalet J-P, Antezana AM, Bienvenu A, Marchal M, Soubervielle J-C, Cauchy E, Le Trong J-L, Dechaux M, Kamici R, Bonaldi K, Westerterp K, Kayser B, Dubray C: Physiological factors in survival at extreme altitude. In Hypoxia and Molecular Medicine. Edited by Sutton JR, Houston CS, Coates G. Burlington, VT: Queen City Printers; 1993:235-251.
• [9]Grocott MP, Martin DS, Levett DZ, McMorrow R, Windsor J, Montgomery HE, Caudwell Xtreme Everest Research Group: Arterial blood gases and oxygen content in climbers on Mount Everest. N Engl J Med 2009, 360(2):140-149.
• [10]Winslow RM, Samaja M, West JB: Red cell function at extreme altitude on Mount Everest. J Appl Physiol 1984, 56(1):109-116.
• [11]West JB, Dollery CT: Distribution of blood flow and ventilation-perfusion ratio in the lung, measured with radioactive carbon dioxide. J Appl Physiol 1960, 15:405-410.
• [12]Michels DB, West JB: Distribution of pulmonary ventilation and perfusion during short periods of weightlessness. J Appl Physiol 1978, 45(6):987-998.
• [13]West JB: Spacelab—the coming of age of space physiology research. J Appl Physiol 1984, 57(6):1625-1631.
• [14]Prisk GK, Paiva M, West JB (Eds): Gravity and the Lung: Lessons from Microgravity. New York: Dekker; 2001.
• [15]Prisk GK, Fine JM, Cooper TK, West JB: Lung function is unchanged in the 1 G environment following 6-months exposure to microgravity. Eur J Appl Physiol 2008, 103(6):617-623.