Limited data exist regarding the efficacy of weight-based dosing of low–molecular weight heparin for venous thromboembolism (VTE) prophylaxis in obese trauma patients.

Consecutive obese trauma patients were placed on a weight-based protocol for VTE prophylaxis (enoxaparin .5 mg/kg subcutaneously every 12 hours). Peak anti-Xa levels were drawn, and bilateral lower extremity duplex ultrasound was performed. The incidence of VTE and bleeding complications were recorded.

Eighty-six patients met the study criteria. Seventy-four patients achieved target prophylactic anti-Xa concentrations, with a mean level of .42 ± .01 IU/mL. Eighteen patients were found to have deep vein thrombosis. However, in 16 of these patients, deep vein thrombosis was diagnosed before weight-based low–molecular weight heparin initiation. No bleeding complications occurred, and no symptomatic pulmonary emboli were identified.

In obese trauma patients, weight-based enoxaparin is an efficacious regimen that provides adequate VTE prophylaxis, as measured by anti-Xa levels, and appears to be safe without bleeding complications.