BACKGROUND: Head injuries in children are responsible for a large number of 
emergency department visits. Failure to identify a clinically significant 
intracranial injury in a timely fashion may result in long term neurodisability 
and death. Whilst cranial computed tomography (CT) provides rapid and definitive 
identification of intracranial injuries, it is resource intensive and associated 
with radiation induced cancer. Evidence based head injury clinical decision 
rules have been derived to aid physicians in identifying patients at risk of 
having a clinically significant intracranial injury. Three rules have been 
identified as being of high quality and accuracy: the Canadian Assessment of 
Tomography for Childhood Head Injury (CATCH) from Canada, the Children's Head 
Injury Algorithm for the Prediction of Important Clinical Events (CHALICE) from 
the UK, and the prediction rule for the identification of children at very low 
risk of clinically important traumatic brain injury developed by the Pediatric 
Emergency Care Applied Research Network (PECARN) from the USA. This study aims 
to prospectively validate and compare the performance accuracy of these three 
clinical decision rules when applied outside the derivation setting.
METHODS/DESIGN: This study is a prospective observational study of children aged 
0 to less than 18 years presenting to 10 emergency departments within the 
Paediatric Research in Emergency Departments International Collaborative 
(PREDICT) research network in Australia and New Zealand after head injuries of 
any severity. Predictor variables identified in CATCH, CHALICE and PECARN 
clinical decision rules will be collected. Patients will be managed as per the 
treating clinicians at the participating hospitals. All patients not undergoing 
cranial CT will receive a follow up call 14 to 90 days after the injury. Outcome 
data collected will include results of cranial CTs (if performed) and details of 
admission, intubation, neurosurgery and death. The performance accuracy of each 
of the rules will be assessed using rule specific outcomes and inclusion and 
exclusion criteria.
DISCUSSION: This study will allow the simultaneous comparative application and 
validation of three major paediatric head injury clinical decision rules outside 
their derivation setting.
TRIAL REGISTRATION: The study is registered with the Australian New Zealand 
Clinical Trials Registry (ANZCTR)- ACTRN12614000463673 (registered 2 May 2014).