Optimization of Venous Thromboembolism Prophylaxis Dosing in Trauma and Ortho Patients

Introduction: Venous thromboembolism (VTE) is a significant complication of trauma, with a risk at least four times other hospitalized patients. The increased risk is secondary to direct damage to vasculature as well as indirect causes including release of tissue factors and depletion of endogenous anticoagulants. Patients with traumatic injury tend to be immobile further increasing their risk. While enoxaparin is the preferred agent for VTE prophylaxis in trauma patients, standard dosing is insufficient for VTE prevention. Studies have evaluated various dosing schemes but an exact dose has not yet been established. The study institution is a level II trauma center participating in the Trauma Quality Improvement Program (TQIP). Institution rates of pulmonary embolism (PE) and deep vein thrombosis (DVT) have been higher compared to other TQIP hospitals. Strategies were implemented to improve VTE rate, mainly a focus on enoxaparin dosing and monitoring. The purpose of this evaluation was to assess the influence of an optimized VTE prophylaxis dosing strategy on DVT and PE rates.


Methods: Practice changes were implemented in November 2023, including updates to all Trauma Services and Trauma Ortho order sets. Enoxaparin is the preferred agent in all patients with a clearance greater than 30 mL/min. The target dose is 0.5 mg/kg rounded to the nearest 10 mg and capped at 60 mg q12h. For severe TBI, the recommended dose is 30 mg q12h. There are no dose exceptions for the elderly. Enoxaparin orders have a pharmacy consult for anti-Xa trough monitoring prior to the fourth or fifth dose with a goal of 0.1 to 0.2 IU/mL.


Results: Prior to implementation, the PE odds ratio (OR) was 1.74 (95% CI 1.09-2.76) and DVT rate was 2.3% compared to 1.2% of TQIP hospitals. Post implementation, the PE OR decreased to 0.87 (95% CI 0.48-1.56). The DVT rate had an absolute reduction of 40% to 1.4%. To ensure elderly patients were not at increased risk for bleeding complications, an analysis of 105 patients was completed. Approximately 50% had an anti-Xa within target range and 25% were below the target. Of the 25% above goal, only half were assessed to need a dose change.


Conclusions: Enoxaparin weight-based dosing with trough anti-Xa monitoring resulted in a significant reduction in VTE rates at a level II trauma center.