The Canadian CT Head Rule (CCHR) is one of the most robust and widely utilized clinical decision instruments in emergency medicine. It guides the judicious use of computed tomography (CT) in patients presenting with minor head trauma.
The Goal of the CCHR
The primary objective of the Canadian CT Head Rule is to standardize the approach to minor head injuries, ensuring that patients at risk for clinically important brain injuries (such as subdural hematomas, epidural hematomas, or significant contusions requiring neurosurgical intervention) receive prompt imaging, while sparing low-risk patients from the ionizing radiation and cost of a CT scan.
Inclusion and Exclusion Criteria
The rule applies to patients with minor head injuries defined as blunt trauma resulting in witnessed loss of consciousness, amnesia, or disorientation, who have an initial ED GCS of 13-15. It does not apply to:
- Patients under 16 years of age.
- Patients on blood thinners or with bleeding disorders.
- Patients with a seizure after the injury.
- Patients with open skull fractures or obvious penetrating trauma.
Clinical Decision Rule: CT indicated if any High Risk or Medium Risk criteria are present following minor head injury with GCS 13-15.
Risk Stratification
The criteria are divided into High Risk (for neurosurgical intervention) and Medium Risk (for clinically important brain injury). If a patient possesses none of the criteria, the rule suggests a CT head is unnecessary. The rule has demonstrated a sensitivity of 100% for predicting the need for neurosurgical intervention.