Deep venous thrombosis in the trauma patient.

Despite improvements in trauma care and thromboembolism prophylaxis over the past 50 years, deep venous thrombosis (DVT) remains a source of morbidity and mortality in the injured patient. Pulmonary embolism may complicate the course of up to 6% of such patients, although the morbidity associated with late development of the postthrombotic syndrome remains poorly defined and perhaps underemphasized. Prolonged immobilization and venous injury contribute to the risk of venous thrombosis, and accumulating evidence suggests underlying imbalances between activated coagulation and fibrinolysis. Much investigative work has focused on identifying subpopulations, including older patients (30 to 40 years) and those with prolonged immobilization, pelvic and lower extremity fractures, spinal cord injury, major venous injury, central venous lines, significant blood requirements, and admission coagulopathy, who are at particular risk of developing DVT. Given the diverse underlying pathophysiologic factors, it is perhaps not surprising that the benefits of prophylactic measures have been imperfect and remain controversial. Both intermittent pneumatic compression and low-dose unfractionated heparin have limitations, although the low-molecular-weight heparins have promise for prophylaxis in this population. It has also been suggested that other measures, such as serial duplex ultrasound screening and prophylactic vena cava filters, may have a role in very high-risk patients and those who are not candidates for other means of prophylaxis. However, the precise role of these measures remains poorly defined and awaits prospective validation. An improved understanding of the operative risk factors may permit prophylactic therapy to be better tailored to the individual patient.