title: Effect of altitude exposure on platelets.
abstract: Since decompression from depth is known to produce a fall in platelet count, the effect of altitude decompression and high-altitude exposure on platelets was investigated. Sixteen subjects decompressed without hypoxia to 20,000 ft simulated altitude for two hours showed a significant (P less than 0.01) drop in circulating platelet count of approximately 10% for three days following decompression. Four of five subjects similarly exposed had a shortened autologous platelet survival compared to that prior to exposure. Subjects exposed to 9,800 ft and then 17,600 ft in a mountain environment showed a significant mean decrease in platelet count on day 2 of 7% and 25% respectively, which had returned to control by day 5. Nonhypoxic and hypoxic decompressed rabbits which received homologous chromium-51-labeled platelets had an increase in lung radioactivity compared with sea-level controls. It is postulated that altitude decompression produces platelet reductions similar to these seen after decompression from depth, and that platelets sequester in the pulmonary vascular bed.
mesh_terms: D000531:Altitude; D000818:Animals; D001772:Blood Cell Count; D001792:Blood Platelets / Q000502:physiology; D002470:Cell Survival; D006801:Humans; D000860:Hypoxia / Q000097:blood; D008099:Liver / Q000473:pathology; D008168:Lung / Q000473:pathology; D011817:Rabbits; D013154:Spleen / Q000473:pathology