PROphylaxis for Venous ThromboEmbolism in Severe Traumatic Brain Injury (PROTEST)

Inclusion Criteria The pragmatic nature of this study seeks to include all consecutive patients presenting with significant TBI, regardless of whether ICB is evident at presentation. Inclusion criteria are the following: i) Patients with severe TBI defined as GCS of ≤8, or ii) Patients with moderate TBI defined as GCS = 9-12, admitted to ICU, with at least some ICB present on initial CT scan and any of the following: 1. Requiring invasive mechanical ventilation at the time of screening 2. Increased ICB on repeat CT scan compared to initial CT scan iii) Upon randomization the patient will be able to receive the first dose of study drug in the first 3 calendar days from the time of injury iv) ≥ 18 years of age Exclusion Criteria All participants meeting any of the following exclusion criteria at baseline will be excluded from participation in this study: i) Known Hypersensitivity to FRAGMIN (Dalteparin), or its constituents including benzyl alcohol or to other low molecular weight heparins and/or heparins or pork products ii) Known history of confirmed or suspected immunologically-mediated heparin-induced thrombocytopenia (delayed-onset severe thrombocytopenia), and/or in patients with a known history of a positive in vitro platelet-aggregation test in the presence of FRAGMIN (Dalteparin) is positive iii) Known septic endocarditis iv) Uncontrollable active bleeding v) Known major blood clotting disorders vi) Known acute gastroduodenal ulcer (with active bleeding) vii) Severe uncontrolled hypertension (i.e. BP\>210 despite medications) viii) Known diabetic or hemorrhagic retinopathy ix) Anticipated to be unable to receive SCD on at least one lower extremity due to nature of injuries for duration of intervention period x) Presence of another confounding factor that can adequately explain the poor GCS at time of presentation (e.g. drug toxicity, seizure) xi) Known presence of irreversible coagulopathies xii) Known Pregnancy xiii) Participants extremely low weight (\<45 kg), or extremely high weight (\>120kg) xiv) Not expected to survive more than 48 hours from admission