The American journal of the medical sciences
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A variety of hemostatic abnormalities has been reported in patients following open-heart surgery. Since surgery itself may induce changes in the coagulation system, the analyses of postoperative coagulation assays in the bleeding patients may be extremely difficult to interpret without an understanding of the coagulation dynamics in the nonhemorrhagic postoperative patients. Thus, we studied the pattern of change in several coagulation assays performed on 36 consecutive patients before and during the first two postoperative weeks. ⋯ Over the following two weeks, the platelet count and platelet adhesiveness returned to normal. Although there was slight lengthening of the Ivy bleeding time on the first postoperative day, this assay was never abnormal. Thus, we conclude that the following cardiopulmonary bypass there is (1) probably activation of circulating procoagulants, (2) progressive increase in fibrinogen levels, (3) activation to the fibrinolytic system, and (4) transient thrombocytopenia with a superimposed platelet defect.