Techniques for evaluating the cause of bleeding in the ICU. Diagnostic clues and keys to interpreting hemostatic tests.

Begin by obtaining both a bleeding and a family history to help ascertain whether the disorder is acquired or inherited. On physical examination, look for multiple bleeding sites or profuse bleeding; these can indicate a systemic bleeding diathesis. Order hemostatic tests. Prolonged aPTT points to a defect in the intrinsic or common coagulation pathway; prolonged PT, to a defect in the extrinsic or common pathway. Thrombin time is abnormal when hypofibrinogenemia, afibrinogenemia, or thrombin inhibitors are present. Bleeding time is prolonged in thrombocytopenia, platelet dysfunction, severe hypofibrinogenemia, and von Willebrand's disease. Factor assays also may be needed to further define the defect.