Prolongation of the template skin bleeding time. Saline (control), protein C activator (PCA; Trp215Ala/Glu217Ala thrombin; WE thrombin), activated protein C (APC), or low-molecular-weight heparin (LMWH; enoxaparin) was administered intravenously to baboons. The bleeding time was determined on the volar surfaces of the lower arms using an FDA-approved method and device (Surgicutt). Several measurements were performed before treatment and between 40 to 60 minutes after the start of treatment. (A) The means of bleeding time prolongations in each treatment dose group and the vehicle-treated controls are shown with the error bars. The dose of the antithrombotic agent is given in micrograms per kilogram of body weight, administered over 70 minutes, and shown next to the treatment label. The 87% average bleeding time prolongation was statistically significant in the highest LMWH dose group. (B) The averages of bleeding time changes in the 4 treatment arms are shown with the 95% confidence intervals (bars). Short-term anticoagulation with PCA (n = 15, average dose 4.9 μg/kg) did not demonstrably impair the hemostasis. APC (n = 9, average dose: 125 μg/kg) had marginal effect and LMWH (n = 23, average dose: 1006 μg/kg) significantly increased the bleeding time.