Table 3

Comparison of the predictor variables in the three clinical decision rules

CATCHCHALICEPECARN <2 yearsPECARN ≥2 years
Mechanism of injury
 Dangerous mechanism of injury (eg, MVC; fall from elevation ≥3 ft (≥0.91 m) or 5 stairs; fall from bicycle with no helmet).High speed RTA as pedestrian, cyclist, occupant (>40 miles/h or 64 km/h)Severe mechanism of injury (MVC with patient ejection, death of another passenger, or rollover; pedestrian/bicyclist without helmet struck by motorised vehicle; falls >0.9 m; head struck by high impact object)Severe mechanism of injury (MVC with patient ejection, death of another passenger, or rollover; pedestrian/bicyclist without helmet struck by motorised vehicle; falls >1.5 m; head struck by high impact object)
Fall >3 m in height
High speed injury from projectile or object
History
Witnessed LOC >5 minLOC ≥5 sAny or suspected LOC
≥3 vomits after head injury (discrete episodes)History of vomiting
Amnesia (antegrade/retrograde >5 min)Not acting normally per parent
Suspicion of NAI
Seizure in patient with no history of epilepsy
 History of worsening headacheSevere headache
Examination
 GCS <15, 2 h after injuryGCS <14, or <15 if <1 y oldGCS <15GCS <15
 Irritability on examinationAbnormal drowsiness (in excess of that expected by examining doctor)Other signs of altered mental status (agitation, somnolence, repetitive questioning, slow response to verbal communication)Other signs of altered mental status (agitation, somnolence, repetitive questioning, slow response to verbal communication)
Positive focal neurology
 Any sign of basal skull fractureSigns of basal skull fracture.Palpable or unclear skull fractureClinical signs of basilar skull fracture
 Suspected open or depressed skull fractureSuspicion of penetrating or depressed skull injury, or tense fontanelle.
 Large boggy scalp haematomaPresence of bruise/swelling/laceration >5 cm if <1 y oldOccipital, parietal or temporal scalp haematoma
  • In each of the three clinical decision rules, the absence of all of the above predictor variables indicates that cranial CT scan is unnecessary.

  • Note: while the predictor variables are reproduced verbatim, the order in which the variables from each clinical decision rule are presented has been altered to facilitate comparison.

  • CATCH, Canadian Assessment of Tomography for Childhood Head Injury; CHALICE, Children's Head Injury Algorithm for the Prediction of Important Clinical Events; GCS, Glasgow coma score; LOC, loss of consciousness; MVC, motor vehicle crash; NAI, non-accidental injury; PECARN, Paediatric Emergency Care Applied Research Network; RTA, road traffic accident.