Prisoners (defined as those directly admitted from correctional facility)

Known or suspected pregnancy

≥ 20% total body surface area (TBSA) burned

Nonsurvivable head injuries

Known hematologic or immunologic disorders

Known prehospital anticoagulant use

Patients initially placed on unfractionated heparin for thromboprophylaxis

Known allergy to Antithrombin or it's components

Enrollment in another interventional study unless approved by Trial Principal Investigator

Antithrombin to Improve Thromboprophylaxis and Reduce the Incidence of Trauma-Related Venous Thromboembolism