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Arterial blood gases and oxygen content in climbers on Mount Everest

Citation

Grocott, MP and Martin, DS and Levett, DZ and McMorrow, R and Windsor, J and Montgomery, HE and Ahuja, V and Aref-Adib, G and Burnham, R and Chisholm, A and Clarke, K and Coates, D and Coates, M and Cook, D and Cox, M and Dhillon, S and Dougall, C and Doyle, P and Duncan, P and Edsell, M and Edwards, LM and Evans, L and Gardiner, P and Gunning, P and Hart, N and Harrington, J and Harvey, J and Holloway, C and Howard, D and Hurlbut, D and Imray, C and Ince, C and Jonas, M and van der Kaaij, J and Khosravi, M and Kolfschoten, N and Luery, H and Luks, A and Meale, P and Mitchell, K and Morgan, G and Morgan, J and Murray, A and Mythen, M and Newman, S and O'Dwyer, M and Pate, J and Plant, T and Pun, M and Richards, P and Richardson, A and Rodway, G and Simpson, J and Stroud, C and Stroud, M and Stygal, J and Symons, B and Szawarski, P and Van Tulleken, A and Van Tulleken, C and Vercueil, A and Wandrag, L and Wilson, M and Basnyat, B and Clarke, C and Hornbein, T and Milledge, J and West, J, Arterial blood gases and oxygen content in climbers on Mount Everest, New England Journal of Medicine, 360, (2) pp. 140-149. ISSN 0028-4793 (2009) [Refereed Article]

DOI: doi:10.1056/NEJMoa0801581

Abstract

Background: The level of environmental hypobaric hypoxia that affects climbers at the summit of Mount Everest (8848 m [29,029 ft]) is close to the limit of tolerance by humans. We performed direct field measurements of arterial blood gases in climbers breathing ambient air on Mount Everest. Methods: We obtained samples of arterial blood from 10 climbers during their ascent to and descent from the summit of Mount Everest. The partial pressures of arterial oxygen (PaO2) and carbon dioxide (PaCO2), pH, and hemoglobin and lactate concentrations were measured. The arterial oxygen saturation (SaO2), bicarbonate concentration, base excess, and alveolar-arterial oxygen difference were calculated. Results: PaO2 fell with increasing altitude, whereas SaO2 was relatively stable. The hemoglobin concentration increased such that the oxygen content of arterial blood was maintained at or above sea-level values until the climbers reached an elevation of 7100 m (23,294 ft). In four samples taken at 8400 m (27,559 ft) - at which altitude the barometric pressure was 272 mm Hg (36.3 kPa) - the mean PaO2 in subjects breathing ambient air was 24.6 mm Hg (3.28 kPa), with a range of 19.1 to 29.5 mm Hg (2.55 to 3.93 kPa). The mean PaCO2 was 13.3 mm Hg (1.77 kPa), with a range of 10.3 to 15.7 mm Hg (1.37 to 2.09 kPa). At 8400 m, the mean arterial oxygen content was 26% lower than it was at 7100 m (145.8 ml per liter as compared with 197.1 ml per liter). The mean calculated alveolar-arterial oxygen difference was 5.4 mm Hg (0.72 kPa). Conclusions: The elevated alveolar-arterial oxygen difference that is seen in subjects who are in conditions of extreme hypoxia may represent a degree of subclinical high-altitude pulmonary edema or a functional limitation in pulmonary diffusion. Copyright © 2009 Massachusetts Medical Society.

Item Details

Item Type:Refereed Article
Research Division:Biomedical and Clinical Sciences
Research Group:Medical physiology
Research Field:Systems physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the health sciences
UTAS Author:Edwards, LM (Dr Lindsay Edwards)
ID Code:64489
Year Published:2009
Web of Science® Times Cited:279
Deposited By:Medicine
Deposited On:2010-08-05
Last Modified:2010-08-05
Downloads:0

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