Evaluation of a novel blood volume-based enoxaparin dosing guideline for venous thromboembolism prophylaxis in trauma patients.

PURPOSE: Fixed-dose and body mass index (BMI)-based enoxaparin regimens provide inadequate venous thromboembolism (VTE) prophylaxis for many trauma patients. The purpose of this study was to evaluate the effectiveness of a novel blood volume (BV)-based enoxaparin guideline vs a historical BMI-based guideline for VTE prophylaxis in trauma patients. METHODS: This was a retrospective pre/post study completed at a large academic level 1 trauma center. All adult trauma patients admitted from October through December 2019 and August through October 2020 who received prophylactic enoxaparin per guideline were included. The BV dosing was as follows: patients with a BV of 3 to 4.9 L received enoxaparin 30 mg every 12 hours, those with a BV of 5 to 6.9 L received 40 mg every 12 hours, and those with a BV of ≥7 L received 60 mg every 12 hours. The primary outcome was the percentage of patients who attained a target anti-factor Xa (anti-Xa) postdosing level at the first steady-state assessment (0.2 to 0.5 IU/mL). RESULTS: A total of 241 patients (99 for the BMI group and 142 for the BV group) were included. The study groups had a median age of 38 vs 42 years, a mean BMI of 27.4 vs 27.7 kg/m2, and a mean BV of 5.1 vs 5.1 L, respectively. A total of 63 patients (62.6%) in the BMI group attained target anti-Xa levels compared to 115 patients (81%) in the BV group (P = 0.008). In multivariate regression, the BV-based guideline was the only variable associated with attainment of target anti-Xa levels (adjusted odds ratio, 2.02; P = 0.01). Clinically relevant bleeding and VTE rates were similar between the groups. CONCLUSION: Dosing prophylactic enoxaparin using a BV-based dosing guideline significantly increased attainment of target anti-Xa levels.

Evaluation of anti-factor Xa concentrations using a body mass index-based enoxaparin dosing protocol for venous thromboembolism prophylaxis in trauma patients.

OBJECTIVE: The aim of this study was to evaluate the effectiveness of a body mass index (BMI)-based enoxaparin prophylaxis dosing protocol at achieving target anti-factor Xa (anti-Xa) concentrations in the trauma population. METHODS: This retrospective chart review evaluated anti-Xa concentrations in adult trauma patients who received prophylactic enoxaparin over a three-month period. The primary outcome was the percentage of patients that achieved target anti-Xa concentrations after ≥3 doses of enoxaparin. Secondary outcomes included correlations of anti-Xa concentrations with enoxaparin dose per BMI, total body weight (TBW), and estimated blood volume (EBV). The prevalence of clinically relevant bleeding and venous thromboembolism was also recorded. Multivariable logistic regression was used to identify associated variables for target anti-Xa concentration attainment. RESULTS: Ninety-nine consecutive patients were included in the study. Included patients were predominately male (69.7%) and Black (50.5%) with a mean age of 44.1 years. Target anti-Xa concentrations were achieved in 62.6% of patients. Anti-Xa concentrations were moderately correlated with enoxaparin dose per EBV (ρ = 0.57), followed by dose per TBW (ρ = 0.46), and dose per BMI (ρ = 0.20). Multivariable logistic regression demonstrated that categorization of enoxaparin dose per EBV and per TBW were the only statistically significant predictors of reaching target anti-Xa concentrations (p = <0.001). CONCLUSIONS: In adult trauma patients, the rate of achieving target anti-Xa concentrations remains suboptimal and provides room for further improvement. Enoxaparin dose per EBV was more closely correlated with anti-Xa concentrations when compared to TBW and BMI. Dosing per EBV and TBW was the only variables associated with reaching target anti-Xa concentrations within the study. Further investigation is warranted to elucidate optimal EBV- and TBW-based dosing regimens.