[Effect of short-term hypoxia on blood platelet function tests of normal subjects]

We studied how smoking and hypoxia affected blood platelet functions. Eighteen normal subjects (ten nonsmokers and eight smokers) inspired 13% oxygen gas and underwent platelet function tests (blood platelet count, MPV, maximum platelet aggregation rate, plasma beta-TG, plasma PF-4) measured just before inspiration and 30 minutes and 60 minutes after inspiration of the gas. Four principal results were obtained. First, breathing room air, blood platelet count and maximum platelet aggregation rate of smokers were significantly increased compared to those of non-smokers. Second, platelet counts and MPV were not affected by hypoxia in either group. Third, the maximum platelet aggregation rate of smokers was significantly decreased by hypoxia. Fourth, in both groups, the plasma levels of beta TG and PF-4 were decreased 30 minutes after inspiration of the 13% oxygen gas. In non-smokers, 60 minutes after inspiration, these plasma levels recovered to the primary levels. Our study showed that blood platelet functions of normal subjects were affected by hypoxia, and the effects of hypoxia on these functions in these two groups were markedly different.