The most recognized risk factors for VTE are venostasis, intimal damage of the vessel wall, and a hypercoagulable state (Virchow’s triad - see Diagram 11.1) (Watanabe & Sant 2001). Patients with a severe brain injury are commonly immobilized for periods of time as a result of extremity or spine fractures they experienced at the time of their injury (Vergouwen et al. 2008). The incidence of DVT appears to be impacted by length of stay in the intensive care unit and the number of days a patient is on a ventilator. There does not appear to be a correlation between DVT incidence and initial Glasgow Coma Scale (GCS) scores, Injury Severity Scale scores, or the Abbreviated Injury Scale score (Denson et al. 2007). Those at highest risk post injury are those who remain on a ventilator longer than 3 days (Olufajo et al. 2016; Raslan et al. 2010). At 1 year post-injury, risk of VTE is greatest for those discharged to extended care facilities compared to home, and for individuals who undergo an operation (Olufajo et al. 2016). Patients involved in trauma that does not specifically involve vessel injury are still at increased risk of thromboembolism, suggesting a trauma-induced hypercoagulable state (Geerts et al. 1994; Geerts et al. 1996). Therefore persons who have sustained a TBI appear to be at increased risk of developing VTE.