Assessment of disorders of coagulation in critical care medicine
Bleeding, thrombosis, or a combination of bleeding and thrombosis, as seen in DIC, are the three major presentations of coagulation disorders in critical care medicine.
Clinical history is the mainstay for recognition and diagnosis of a clinically significant bleeding state or predisposition for developing thrombosis. History should be verified for bleeding complications after previous surgical procedures, trauma, or tooth extraction. Family history may raise uspicion of a hereditary coagulation disorder (hemophilia, von Willebrand's disease, rare thrombopathies) or thrombophilia. The patient may be known to have an underlying disease, such as chronic parenchymal liver disease, renal failure (uremia, proteinuria), a myeloproliferative syndrome, or a malignancy, which may lead to coagulation disorders.
Ingestion of drugs affecting hemostasis (e.g. aspirin, non-steroidal anti-inflammatory drugs, heparin, coumarin, chemotherapy) should be investigated thoroughly.
If, based on the above assessment, there is suspicion of a specific and classified diagnosis, appropriate laboratory tests should be performed. If no diagnosis has been made after a specific medical history and corresponding laboratory investigation, a general coagulation screening should be instituted.
General screening should include at least a platelet count, prothrombin time, and activated partial thromboplastin time. The outcome of these tests may help to establish the cause of bleeding (Table 1). It should be stressed that severe profuse bleeding may be the first sign of overt DIC ( T§bl§..,.2).
Table 2 Coagulation tests in thrombohemorrhagic disorders