Pulmonary gas exchange on the summit of Mount Everest

West, John B.; Hackett, Peter H.; Maret, K. H.; Milledge, J. S.; Peters, Richard M.; Pizzo, C. J.; Winslow, R. M.

doi:10.1152/jappl.1983.55.3.678

Cited by 183 publications

(72 citation statements)

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“…Results were reproducible and agreed with those of a previous field study (AMREE) [4]. In particular, we also found that PA,O 2 did not decline further from Camp 3 at 7,467 m to the South Col at 8,000 m.…”

Section: Discussionsupporting

confidence: 91%

“…Mean data are presented in figure 4. Once again, Operation Everest II data [5] are presented alongside, as well as available data from the AMREE [4]. Mean (±SEM) values for PA,O 2 declined from 8.5±0.2 kPa (64±1.6 mmHg) on Lamjura Pass to 5.1±0.08 kPa (38±0.6 mmHg) at 7,467 m at Camp 3, but there was no further decline at 8,000 m (PA,O 2 5.1±0.2 kPa (38±1.2 mmHg)).…”

Section: Alveolar (End-expiratory) Partial Pressure Of Oxygenmentioning

confidence: 99%

“…The American Medical Research Expedition to Everest (AMREE) (1981) measured alveolar partial pressure of oxygen (PA,O 2 ) in gas samples from four subjects on the South Col (8,000 m), one subject at 8,400 m and one subject on the summit (8,848 m). However, these values were not compared with measures of arterial oxygenation, such as arterial partial pressure of oxygen (Pa,O 2 ) or arterial oxygen saturation (Sa,O 2 ) at the same altitudes [4], although oxygen saturation was calculated from the measured PA,O 2 [5].…”

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confidence: 99%

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Gas exchange at extreme altitude: results from the British 40th Anniversary Everest Expedition

Peacock

Jones²

1997

Eur Respir J

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Since Messner and Habeler climbed to the summit of Mount Everest (8,848 m) without oxygen in 1978, there has been controversy between scientists trying to explain this feat. Field studies have suggested better respiratory performance than that found during a simulated climb in a hypobaric chamber, but the lack of data at extreme altitude has hampered the debate.We measured arterial oxygen saturation (Sa,O 2 ) and alveolar partial pressure of oxygen (PA,O 2 ) in nine subjects as they climbed from 3,500 to 8,000 m. Four of the climbers reached 8,000 m and one reached the summit. We also tested the effects of breathing supplementary oxygen on Sa,O 2 at 6,550 and 8,000 m.At all altitudes tested, we found that both PA,O 2 and Sa,O 2 were higher than expected from low pressure chamber studies. We also found that standard rates of supplementary oxygen (2 L·min -1 ) were insufficient to restore Sa,O 2 above 90% at 8,000 m.The respiratory performance of climbers at extreme altitude is better than expected from sea-level chamber studies, which may, in part, explain why humans can reach the summit (8,848 m) without added oxygen. The better performance is likely to be due to more appropriate acclimatization.

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Section: Discussionsupporting

confidence: 91%

Section: Alveolar (End-expiratory) Partial Pressure Of Oxygenmentioning

confidence: 99%

mentioning

confidence: 99%

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Gas exchange at extreme altitude: results from the British 40th Anniversary Everest Expedition

Peacock

Jones²

1997

Eur Respir J

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“…Barometric pressure at sea level is ;760 mmHg (containing 20.9% oxygen) corresponding to a PiO 2 of 160 mmHg (2). At 8,848 m, the altitude at the summit of Mount Everest, the barometric pressure is ;253 mmHg and the PiO 2 is ;42 mmHg, which results in almost immediate unconsciousness in unacclimatized subjects (3).…”

Section: Altitudementioning

confidence: 99%

Physical Activity at Altitude: Challenges for People With Diabetes

Mol

Vries²,

Koning

et al. 2014

Diabetes Care

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A growing number of subjects with diabetes take part in physical activities at altitude such as skiing, climbing, and trekking. Exercise under conditions of hypobaric hypoxia poses some unique challenges on subjects with diabetes, and the presence of diabetes can complicate safe and successful participation in mountain activities. Among others, altitude can alter glucoregulation. Furthermore, cold temperatures and altitude can complicate accurate reading of glucose monitoring equipment and storage of insulin. These factors potentially lead to dangerous hyperglycemia or hypoglycemia. Over the last years, more information has become available on this subject. PURPOSETo provide an up-to-date overview of the pathophysiological changes during physical activity at altitude and the potential problems related to diabetes, including the use of (continuous) blood glucose monitors and insulin pumps. To propose practical recommendations for preparations and travel to altitude for subjects with diabetes. DATA SOURCES AND SYNTHESISWe researched PubMed, medical textbooks, and related Internet sites, and extracted human studies and data based on relevance for diabetes, exercise, and altitude. LIMITATIONSGiven the paucity of controlled trials regarding diabetes and altitude, we composed a narrative review and filled in areas lacking diabetes-specific studies with data obtained from nondiabetic subjects. CONCLUSIONSSubjects with diabetes can take part in activities at high, and even extreme, altitude. However, careful assessment of diabetes-related complications, optimal preparation, and adequate knowledge of glycemic regulation at altitude and altitude-related complications is needed.An increasing number of subjects with diabetes reside at high altitude for short periods of time, partly for work, but mainly for recreational purposes such as skiing, trekking, and climbing. Exercise under conditions of hypobaric hypoxia poses some unique challenges for subjects with diabetes and could potentially lead to dangerous situations such as unexpected hypoglycemia and hyperglycemia, inaccurate

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“…The low PA,O 2 limits the alveolar-arterial driving gradient for oxygen uptake and, in combination with a lower mixed venous oxygen tension, also delays alveolar-capillary equilibration [13]. These issues are of greater concern during exercise when the smaller pressure differential across the alveolar-capillary barrier, in conjunction with the increased cardiac output, shortened capillary transit time and greater venous oxygen desaturation, create an effective diffusion limitation for oxygen that leads to further arterial desaturation [9,10,14].…”

Section: Gas Exchange and Oxygen Deliverymentioning

confidence: 99%

Travel to high altitude with pre-existing lung disease

Luks

Swenson²

2007

European Respiratory Journal

105

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The pathophysiology of high-altitude illnesses has been well studied in normal individuals, but little is known about the risks of high-altitude travel in patients with pre-existing lung disease. Although it would seem self-evident that any patient with lung disease might not do well at high altitude, the type and severity of disease will determine the likelihood of difficulty in a high-altitude environment. The present review examines whether these individuals are at risk of developing one of the main forms of acute or chronic high-altitude illness and whether the underlying lung disease itself will get worse at high elevations. Several groups of pulmonary disorders are considered, including obstructive, restrictive, vascular, control of ventilation, pleural and neuromuscular diseases. Attempts will be made to classify the risks faced by each of these groups at high altitude and to provide recommendations regarding evaluation prior to high-altitude travel, advice for or against taking such excursions, and effective prophylactic measures.

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Pulmonary gas exchange on the summit of Mount Everest

Cited by 183 publications

References 0 publications

Gas exchange at extreme altitude: results from the British 40th Anniversary Everest Expedition

Gas exchange at extreme altitude: results from the British 40th Anniversary Everest Expedition

Physical Activity at Altitude: Challenges for People With Diabetes

Travel to high altitude with pre-existing lung disease

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