BACKGROUND: Appropriate prophylaxis against venous thromboembolism (VTE) remains undefined. This study evaluated an anti-Xa-guided enoxaparin thromboprophylaxis protocol on the incidence of VTE in high-risk trauma patients based upon Greenfield’s Risk Assessment Profile (RAP) score. METHODS: This is a retrospective observational study of patients admitted to a trauma ICU over a 12-month period. Patients were included if they received anti-Xa-guided enoxaparin thromboprophylaxis. Dosage was adjusted to a prophylactic peak anti-Xa level of 0.2-0.4 IU/ml. Subgroup analysis was performed on high-risk patients (RAP score ≥ 10) who received lower extremity duplex ultrasound surveillance for deep vein thrombosis (DVT). Data are expressed as mean ± standard deviation. Significance was assessed at p<0.05. RESULTS: 131 patients received anti-Xa-guided enoxaparin thromboprophylaxis. Four patients were excluded for age or acute VTE on admission. 56 patients with RAP score ≥ 10 and surveillance duplex evaluations were included in the subgroup analysis with mean age 43±20 years, injury severity score 25±10, and RAP score 16±4. Prophylactic anti-Xa levels were initially achieved in 34.6% of patients. An additional 25.2% required 40-60mg BID to reach prophylactic levels. 39.4% never reached prophylactic levels. Weight, BMI, ISS, and RAP score were significantly higher with sub-prophylactic anti-Xa levels. One patient developed bleeding complications (0.8%). No patient developed intra-cerebral bleeding or heparin-induced thrombocytopenia.Nine VTE occurred in the high-risk subgroup, including four DVT (7.1%), all asymptomatic, and five pulmonary emboli (8.9%). The historical rate of DVT in similar patients (ISS 31±12 and RAP score 16±5) was 20.5%, a significant decrease [p=0.031]. Mean chest AIS scores were significantly higher for patients developing pulmonary emboli than DVT, 3.0±1.1 vs 0.0 [p<0.001]. CONCLUSIONS: Mean chest AIS was higher in patients developing PE. Increased weight, BMI, ISS, and RAP score are associated with sub-prophylactic anti-Xa levels. Anti-Xa-guided enoxaparin dosing reduced the rate of DVT from 20.5% to 7.1% in high-risk trauma patients. LEVEL OF EVIDENCE: Retrospective study using historical controls, level IV.
ASJC Scopus subject areas
- Critical Care and Intensive Care Medicine