Effects of hypoxia on platelet activation in pilots.

In order to evaluate the effect of hypoxia on platelet activation, 53 pilots were chosen for this study. Thirty were selected as the hypoxic group, and the other 23 as a control group. The plasma concentration of thromboxane B2(TXB2), 6-keto-prostaglandin f1 alpha (6-keto-PGF1 alpha), beta-thrombo-globulin (BTG) and platelet factor 4 (PF4) were measured during altitude chamber tests. After staying at 5000 m for 15 min, the plasma level of TXB2, BTG and PF4 increased significantly over pre-test levels (p < 0.01), but 6-keto-PGF1 alpha had no distinct change (p > 0.05). These changes indicate that moderate acute hypoxia causes increases in platelet activation, but has less effects on the endothelial cells.