Prevention:
     - coumadin, low molecular weight dextran, adjusted dose heparin, or low molecular weight heparin are proven effective for patients undergoing elective surgery

Low Risk Trauma Patients w/ Lower Extremity Fracture:
      - prophylaxis may be considered for patients with risk factors (female, obese, birth control, smoking ect).
      - references:
              - Prophylaxis of deep-vein thrombosis in fractures below the knee: a prospective randomised controlled trial.
              - Efficacy and safety of rivaroxaban versus low-molecular-weight heparin therapy in patients with lower limb fractures.
              - Symptomatic venous thromboembolism following fractures distal to the knee: a nationwide danish cohort study.
              - UK national survey of venous thromboembolism prophylaxis in ankle fracture patients treated with plaster casts.

              - Incidence of deep-vein thrombosis in patients with fractures of the ankle treated in a plaster cast.
              - Deep vein thrombosis following below knee immobilization: the need for chemoprophylaxis.
              - Risk factors of venous thrombosis in patients with ankle fractures.

High Risk Trauma Patients:
      Vena cava filter
             - in multi-trauma patients consider prophylactic placement of a vena cava filter
             - decrease in incidence of pulmonary embolism can be expected
             - filters should remove 98% of emboli
             - filters can be expected to prevent fatal emboli in about 2-4% of patients undergoing major acetabular fixation (as compared to patients
                        who receive other forms of DVT prophylaxis)
             - long-term patency rate of IVC is about 94% at 1-2 years
             - sudden severe leg edema following filter insertion may indicate the occurance of a large embolus
             - criteria for filter placement (2/5 criteria must be met)
                      - age greater than 55 yrs
                      - ISS greater than 16
                      - complex pelvic fracture
                      - long bone and pelvic fracture
                      - fracture (pelvic / lower extremity) requiring prolonged bed rest

   - in the study by Wojcik, et al. (2000), long-term complications of VCF placement  were 191 VCFs,  mean follow-up of 28.9 months
       - 41 VCFs were placed in patients with DVT or pulmonary embolism, and 64 were placed in patients for prophylactic
       - there were no pulmonary embolisms detected after VCF insertion
       - only one filter (0.95%) migrated, and this was minimal (1 cm cephalad)
       - 1 (0.95%) vena cava was occluded, based on duplex ultrasonography, and 11 patients (10.4%) had signs or symptoms
                   of leg swelling after hospital discharge
       - 28 (44%) of the 64 patients with prophylactic VCFs developed a DVT after filter placement
       - VCFs placed in trauma patients have acceptable short- and long-term complication rates
        - consideration should be given to prophylactic VCF placement in patients at high risk for VTE
        - randomized controlled trials are needed to evaluate whether VCF insertion increases the risk for subsequent DVT
 
reference:
      - Long-Term Follow-Up of Trauma Patients with a Vena Caval Filter
      - Magnetic resonance venography to evaluate the deep venous system of the pelvis in patients who have an acetabular fracture.
      - Prophylactic vena cava filter insertion in selected high risk orthopaedic trauma patients.
      - Greenfield filter prophylaxis of pulmonary embolism in patients undergoing surgery for acetabular fracture.
      - Thromboembolism following multiple trauma.
      - Risk of pulmonary emboli in patients with pelvic fractures.
      - Prophylaxis against deep-vein thrombosis following trauma: a prospective, randomized comparison of mechanical and pharmacologic prophylaxis.
      - Long-term consequences of pelvic trauma patients with thromboembolic disease treated with inferior vena caval filters.