Grant: Project Grant

Emergency departments are treating more people who are prescribed blood thinners (anticoagulants) than ever before. Blood thinners are helpful to prevent strokes and blood clots, but they can also increase the chances of bleeding problems. People who take blood thinners are told to go to the emergency department if they have a head injury, because they could develop a brain bleed. Until now, there has been little research on the risk of having a brain bleed after a head injury in people taking blood thinners. It was assumed that the risk of a brain bleed is high, so guidelines advise having a head CT scan even if the head injury is minor and the patient feels well. Our investigator group found that the risk of a brain bleed is not as high as once thought. Most emergency doctors use a test called the Canadian CT Head Rule to determine whether a head scan is needed for people with a head injury. In people who take blood thinners, this test almost always leads to a CT scan. Although CT scans are quite safe, unnecessary scans can cause longer wait times in the emergency department and delay scans for people who really need them. We plan to conduct the largest study ever done on people who are prescribed blood thinners with a head injury. We will develop a new bedside decision rule (or test) which will tell the doctor if a CT scan is needed or not. The study will recruit 5000 emergency department patients from Canada, the United States and Britain. Patients are entered into the study if they are on blood thinners and come to the emergency department with a head injury. Everyone will have a head scan as customary, and we will develop the new rule at the end of the study. If our new rule is safe and effective, it would not only reduce unnecessary CT scans but also allow physicians to immediately reassure many patients that they do not have a brain bleed.