Enoxaparin 40mg Twice Daily with Peak Anti-Xa Adjustments is Safe and Necessary to Achieve Therapeutic Chemoprophylaxis in Burn-Injured Patients

Abstract

Burn injury results in hypercoagulability and an increased venous thromboembolism risk. However, the most effective chemoprophylaxis for burn-injured patients has yet to be elucidated. Therefore, this study aims to identify the safety and efficacy of a burn center's venous thromboembolism protocol modification which increased the dose of enoxaparin from 40mg daily to 40mg twice daily with peak anti-Xa level adjustments. It was hypothesized that this change would not increase bleeding complications and would decrease venous thromboembolism rates. All adult, burn-injured patients admitted to a regional burn center were retrospectively reviewed one year before and after the implementation of this protocol modification. There were no differences in demographics, injury characteristics, or hospital length of stay between the pre- (n=432) and post-protocol modification (n=407) groups. Bleeding complications did not increase in the post-protocol group, including intraoperative blood loss (50 vs 25cc), the total number of transfusions (9.0 vs 6.0 units), and GI bleeding events (0.7 vs 0.2%) (all p>0.05). Most patients receiving enoxaparin 40mg twice daily achieved an initial therapeutic level based on peak anti-Xa measurements (46.5%), yet the rate of venous thromboembolisms between pre- and post-protocol groups was not statistically different (1.4 vs 0.7%, p=0.5072). Factors associated with an initial sub- or supratherapeutic peak anti-Xa level were percent total body surface area, weight, body mass index, and creatinine clearance. Overall, this study demonstrated that a higher dose of enoxaparin (40mg twice daily) with peak anti-Xa level adjustments was safe in burn-injured patients and necessary to obtain therapeutic levels of chemoprophylaxis.

Keywords: anti-Xa levels; bleeding complications; enoxaparin; venous thromboembolism.