Venous thromboembolism prophylaxis for patients receiving regional anesthesia following injury in Iraq and Afghanistan.

Background: Soldiers with combat-related traumatic injury are at high risk for venous thromboembolism (VTE) and often require regional anesthesia (RA) for pain control. We evaluated whether the recommended reduction in chemoprophylaxis in the presence of RA increases VTE rates.

Methods: We collected data each hospital day for all soldiers admitted to the Walter Reed Army Medical Center following injury in Iraq or Afghanistan. We analyzed thromboprophylaxis and RA rates and assessed risk factors for VTE. We separated outcomes by whether RA was central neuraxial (cNAB) or peripheral blockade.

Results: Among 1,259 patients, 323 received RA for a median of 12 days (5-27 days). Those with RA were younger and more likely to have been injured in combat or by an improvised explosive device. They also received more packed red blood cell transfusions and had longer admissions. Patients with RA spent a greater percentage of days on enoxaparin 40 mg daily compared with those without RA (34.4% vs. 22.0%, p < 0.001) and more hospital days without any chemoprophylaxis (2.0 [1.0-6.0] vs. 1.0 [0.0-3.0], p < 0.001). Patients with cNAB were less likely to be placed on enoxaparin 30 mg twice daily. Patients with RA in place had mechanical prophylaxis ordered at the same rate as those without RA. Neither the presence of any RA nor cNAB specifically was associated with an increased risk for VTE. No bleeding or neurologic complications occurred in those receiving RA.

Conclusion: Despite changes to chemoprophylaxis, soldiers wounded in combat who receive RA are not at increased risk for VTE.

Level Of Evidence: Therapeutic study, level III.