Key result
Acute high-altitude ascent frequently triggers small pericardial effusions in healthy lowlanders.
Why the study?
Acute ascent to high altitude causes illness including AMS, HAPE, and HACE, with increased vascular permeability possibly due to oxidative stress; small pericardial effusions at high altitude had not been reported.
RCT (n=83)
double blind
randomized
Antioxidant supplementation fails to prevent AMS; challenges oxidative stress hypothesis and does not support routine prophylaxis in high-altitude ascent.
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. 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 …
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Thompson et al. (2006) conducted an RCT in Acute mountain sickness (n=83). Antioxidant supplementation vs. Placebo was evaluated on Symptoms of acute mountain sickness (AMS). In a trial of antioxidant supplementation versus placebo, small pericardial effusions were unexpectedly observed in many of the 83 healthy lowlanders after acute ascent to 5200 m.
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