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Acute ascent to high altitude causes illness ranging from relatively trivial symptoms of acute mountain sickness (AMS) to rapidly fatal conditions including high altitude pulmonary oedema (HAPE) and high altitude cerebral oedema (HACE).1 HAPE, HACE, and oedema in other tissues at altitude may have a common pathogenesis in increased vascular permeability. There is some evidence that this increased permeability may be caused by oxidative stress.2 In conducting a trial of antioxidant supplementation in healthy adults acutely exposed to high altitude, we unexpectedly found small pericardial effusions in many subjects at high altitude. This has not been reported elsewhere.
PARTICIPANTS AND METHODS
The study was approved by the Lothian Research Ethics Committee. Eighty three lowlanders (median age 21 years, range 18–30, 44 men) participated in a randomised, placebo controlled, double blind trial of antioxidant supplementation. Subjects flew to La Paz, Bolivia (3650 m) and after 4–5 days’ acclimatisation ascended over 90 minutes to the Chacaltaya laboratory (5200 m) by off road vehicle. The antioxidant group (41 subjects) received 1 g l-ascorbic acid, 400 IU α tocopherol acetate, and 600 mg α lipoic acid/day in four divided doses starting five days before ascent to 5200 m.
The primary objective of the trial was to determine whether antioxidant supplementation could reduce the symptoms of AMS. A secondary …
Footnotes
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Sources of support: Siemens Medical Solutions UK: loan of Acuson Cypress Echocardiography device. Cultech Ltd: donation of antioxidant supplement and matched placebo
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Competing interests: All authors have nothing to declare
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Institution(s) to which the work should be attributed: Apex (Altitude Physiological Expeditions SC030345), University of Edinburgh
The pooled data of this study were presented at the British Cardiac Society conference in 2004.
Contributions of authors: J B Irving recorded the novel finding of pericardial effusions and contributed to the manuscript; A A R Thompson and J K Baillie analysed the data and wrote the manuscript; M Toshner and J B Irving conducted echocardiography; J K Baillie, A A R Thompson, S R J Maxwell, and D J Webb designed and conducted the trial of antioxidant supplementation and contributed to the manuscript; A A R Thompson led the Apex 2 expedition.