A Weight- and Anti-Xa-Guided Enoxaparin Dosing Protocol for venous thromboembolism Prophylaxis in intensive care unit Trauma Patients

Abstract

Trauma patients are high risk for venous thromboembolism (VTE) and the optimal dosing strategy for prophylactic enoxaparin remains unknown. The purpose of this quality improvement project was to evaluate a weight-based and anti-Xa-guided enoxaparin dosing protocol in intensive care unit (ICU) trauma patients and to determine if the protocol led to reduced clinical VTE rates. Adult trauma patients admitted for ≥ 48 hours to our surgical or neurosurgical ICUs who received ≥ 3 consecutive weight-based enoxaparin doses were eligible for inclusion into this pre-post implementation cohort study. Enoxaparin 30 mg every 12 hours was used for weight 50 to 100 kg and body mass index (BMI) < 40 kg/m2 and enoxaparin 40 mg every 12 hours for weight ≥ 100 kg or BMI ≥ 40 kg/m2. PRE cohort patients did not routinely receive anti-Xa level monitoring, while in the POST cohort, dosing was subsequently titrated to peak anti-Xa levels of 0.2 to 0.4 IU/mL. A total of 110 and 113 patients were included in the PRE and POST cohorts, respectively. Clinical VTE rates were similar between groups. In the POST cohort, 75% of patients achieved goal anti-Xa levels without dose titrations, while 12% of higher weight patients and 9.1% of lower weight patients required adjustment. When comparing weight quartiles, patients > 100 kg were more likely to have sub-prophylactic anti-Xa levels than those ≤ 69 kg. Our enoxaparin dosing protocol was safe and frequently achieved initial anti-Xa levels within goal, indicating that weight-based dosing alone may be sufficient. However, patients > 100 kg may benefit from anti-Xa monitoring as they are highest risk for sub-prophylactic levels despite higher initial enoxaparin dosing.