EBQ:Canadian Head CT Rule

incomplete Journal Club Article

Stiell IG, et al. "The Canadian CT Head Rule for patients with minor head trauma". The Lancet. 2001. 357(9266):1391-96.
PubMed Full text PDF

Clinical Question

Can a decision rule be used to determine which patients require CT imaging after head trauma?

Conclusion

The Canadian CT head rule is a effective method for determining the need for a patient to receive a non contrast brain CT after head trauma.

Major Points

The trial found that the following criteria had 100% sensitivity for identifying patient at risk for neurologic intervention with minor head injury

1. GCS score <15 at 2h post injury
2. Suspected open or depressed skull fracture
3. Any sign of basal skull fracture (hemotympanum, ‘racoon’ eyes, cerebrospinal fluid otorrhoea/rhinorrhoea, Battle’s sign)
4. Vomiting ≥ 2episodes
5. Age ≥ 65 years

• Minor head injury is defined as witnessed loss of consciousness, definite amnesia, or witnessed disorientation in a patients with a GCS score of 13–15

The moderate risk group (for brain injury on CT) was identified with 95% sensitivity if any of the following were present:

1. Amnesia before impact >30 min
2. Dangerous mechanism (pedestrian struck by motor vehicle, occupant ejected from motor vehicle, fall from height >3 feet or five stairs)

Design

• Prospective cohort study in 10 Canadian community and teaching institutions
• N=3121

Population

Inclusion Criteria

• Blunt Trauma to the head causing witnessed loss of consciousness, definite amnesia, or witnessed disorientation)
• GCS ≥ 13 on ED arrival
• Head injury within the last 24 hours

Exclusion Criteria

• Less than 16 years old
• Minimal head injury (no loss of consciousness, amnesia, or disorientation)
• No clear history of trauma as the primary event (eg, primary seizure or syncope)
• Obvious penetrating skull injury or obvious depressed fracture
• Acute focal neurological deficit
• Unstable vital signs associated with major trauma
• Seizure before assessment in the ED
• Bleeding disorder
• Using oral anticoagulants
• Returned for reassessment of the same head injury
• Pregnant

Baseline Characteristics

• Mean age: 38 years
• Age range 16-99
• Men: 69%
• Mean time between injury and physician assessment: 3.1 hours
• Arrival by ambulance: 73%
• Transfer from outside hospital: 13%
• Witnessed loss of consciousness: 46%
• Amnesia: 87%
• Initial GCS score:
  • 15: 80%
  • 14: 17%
  • 13: 4%
• Mechanism of injury:
  • Fall: 31%
  • MVA: 26%
  • Assault: 11%
  • Sports: 10%
  • Bicycle: 7%

Interventions

• Patients underwent standard CT of the head according to the judgment of the treating physician.
• The reliability of the radiography interpretations was assessed by having abnormal CT scans, and 5% (randomly selected) of normal scans reviewed by a second radiologist who was unaware of the first interpretation.
• Patients were classified as having no clinically important brain injury if af 14 days they had:
  • no complaints of memory or concentration problems
  • no seizures
  • NO focal motor findings
  • Score ≤ 10 on the Katzman Short Orientation-Memory-COncentration Test
  • Returned to normal daily activities

Funding

Funded by peer-reviewed grants from the Medical Research Council of Canada (MT-13699) and the Ontario Ministry of Health Emergency Health Services Committee (11896N)