Unless contraindicated, all admitted trauma patients should receive Sequential Compression Device (SCD) therapy as primary VTE prophylaxis. Chemical VTE prophylaxis should be initiated for all trauma patients 24 hours after injury unless contraindicated due to high risk of bleeding or in certain high risk special populations (see below). There are two options for chemical VTE prophylaxis:
1. Low Molecular Weight Heparin (LMWH).
a. Subcutaneous (SC) Enoxaparin 30 mg twice daily should be considered for most trauma patients with normal creatinine clearance (>30 mg/dL). Most patients in the austere deployed setting should continue with 30 mg twice daily, which has been shown to be superior to 5000 U of unfractionated heparin three times daily for the prevention of VTE in patients with normal creatinine clearance (CrCI). 16,18
b. Weight-based enoxaparin dosing is an acceptable alternative for trauma patients with a normal creatine clearance. Options include twice daily doses of 0.5-0.6 mg/kg,19-21 or 30 mg for 50 to 60 kg patients, 40 mg for 61 to 99 kg patients, and 50 mg for patients greater than 100 kg.22 Anti-Xa levels should be monitored when weight-based enoxaparin is administered because trauma patients experience fluctuations in creatinine clearance that might require dose adjustment. 23
c. Lower doses of enoxaparin can be considered in patients who weigh less than 50 kg. . For these patients, enoxaparin weight-based dosing (0.5-0.6 mg/kg) BID can be considered.
d. Enoxaparin is renally excreted and should be avoided in patient with renal failure since it may lead to increased bleeding complications. 24 In this population heparin SQ 5000 U TID is recommended for CrCl <30 mg/dL.
e. The rate of Heparin Induced Thrombocytopenia (HIT) after prophylactic enoxaparin is 0% compared to 2.7% with prophylactic unfractionated heparin.25,26 Therefore, routine platelet monitoring is not required for trauma patients who are exposed only to enoxaparin.
2. Low dose Unfractionated Heparin (UFH)13-15
a. While enoxaparin is the preferred agent for chemical VTE prophylaxis in trauma patients with normal creatinine clearance, subcutaneous unfractionated heparin at 5000 U every 8 hours is preferred for patients with end-stage renal disease or a creatinine clearance of <30 mg/dL. 24
b. In patients receiving UFH, platelet monitoring is recommended to monitor for HIT approximately every 3 days from day 4 to day 14 or until pharmacologic prophylaxis is stopped.25 If HIT is diagnosed, heparin anticoagulants must be replaced with nonheparin anticoagulants (such as the direct thrombin inhibitor argatroban). These agents can be challenging to obtain and monitor in the deployed environment because these agents are irreversible and appropriate therapeutic levels are difficult to maintain. 25,27,28
Pharmacologic prophylaxis with direct oral anticoagulants (DOACs) or aspirin should not be a primary choice for pharmacologic prophylaxis for most trauma patients because of the lack of related clinical trials.
Post discharge prophylaxis should be considered for patients with TBI, orthopedic or spine injuries and for those who underwent major surgery. Godat et al. reported that trauma patients who are at the highest risk to develop VTE (especially spinal cord injury with/without pelvic fracture) are at the greatest risk during the first three months after injury and that this risk decreases at six months post injury.3.23