Achievement of goal anti-Xa activity with weight-based enoxaparin dosing for venous thromboembolism prophylaxis in trauma patients

Study Objective: The purpose of this study was to evaluate the utility of routine anti-Xa peak monitoring for trauma patients initiated on weight-based enoxaparin for venous thromboembolism (VTE) prophylaxis and identify patient populations where monitoring is necessary. Design: Retrospective study. Setting: Augusta University (AU) Medical Center in Augusta, Georgia, a level 1 trauma center. Patients: Adult patients admitted to the trauma surgery service requiring chemical VTE prophylaxis. Intervention: At least three consecutive doses of enoxaparin 0.5 mg/kg subcutaneously every 12 hour for VTE prophylaxis prior to an anti-Xa peak as the initial chemical VTE prophylaxis strategy. Measurements: The primary end point was the percentage of patients who achieved goal anti-Xa peak of 0.2–0.6 unit/ml. The incidence of newly diagnosed VTE and clinically significant bleeding were assessed as secondary end points. Main Results: From January 1, 2018, through February 28, 2019, 300 patients met inclusion criteria. Anti-Xa peaks were within goal in 91% of all patients, 7.7% were below goal, and 1.3% were above goal. For patients who did not meet the goal, dose adjustments were made in 70.4% of patients. New levels were obtained in 73.7% of those patients, and all repeat levels was within goal. Clinically significant bleeding occurred in 5.3% of patients. Newly diagnosed VTE occurred in 1.7% of patients. Conclusions: The use of initial weight-based enoxaparin dosing in trauma patients routinely achieved the prespecified target anti-Xa goal. In conclusion, anti-Xa levels are not necessary for routine monitoring of weight-based enoxaparin for VTE prophylaxis in trauma patients. Incidence of clinically significant bleeding and newly diagnosed VTE were similar to previous studies.