Reassessment of a Piloted Enoxaparin Dosing Schedule for Venous Thromboembolism Prophylaxis in Burn Patients

Abstract Introduction Burn patients face a heightened risk of venous thromboembolism (VTE) secondary to endothelial injury, immobility, and systemic hypercoagulability, making prophylaxis essential. Standard prophylactic enoxaparin dosing often fails to achieve adequate anti-coagulation (measured as target anti-Xa levels) in this population. Our institution previously piloted a revised VTE prophylaxis protocol, evaluated in a small cohort. This study expands our analysis to a larger cohort to assess safety and efficacy. Methods This single-center, retrospective cohort study compared a historical protocol group (3/1/21 - 5/31/21) with a new protocol group (7/1/22 - 8/31/22), with further analysis of additional new-protocol patients (11/20/23 - 3/2/2025). Adults with cutaneous/inhalation burns who received prophylactic enoxaparin with anti-Xa monitoring were included. Exclusions were non-burn admissions, frostbite injuries, and incarcerated status. The primary endpoint was protocol efficacy defined as percent of initial anti-Xa levels within goal range and time to goal anti-Xa level. Secondary endpoints evaluated were VTE incidence (inpatient/post-discharge), dosing interruptions with VTE, correlation to published enoxaparin dosing equations in burn patients, and bleeding events. Results The median (IQR) initial anti-Xa level in the historical (n = 29) vs. new protocol group (n = 134) was 0.09 (0.04-0.14) units/mL vs. 0.22 (0.16-0.28) units/mL (p.001). The median (IQR) time for patients to achieve goal anti-Xa level was 6 (3-8) days in the historical protocol and 3 (2-4) days in the new protocol group (p=.003). This improvement contrasts with our prior smaller analysis, in which time-to-target anti-Xa did not differ significantly (p=.456). Rates of inpatient VTE (p=.662), major bleeding (p=.068), and minor bleeding (p=.415) were comparable between groups. No other secondary outcomes differed significantly. Conclusions Implementation of the revised protocol improved both initial anti-Xa levels and time to therapeutic range without increasing bleeding risk. The median anti-Xa value improved significantly from subtherapeutic to within goal range with the revisions to the protocol. Applicability of Research to Practice This novel protocol more quickly and reliably achieves therapeutic levels of enoxaparin than previous protocols, without compromising safety. It can be replicated and utilized by other burn centers and warrants a multicenter analysis. Funding for the study N/A.