The year 2019 marks the 10th anniversary of the publication of the Pediatric Emergency Care Applied Research Network clinical decision instrument for the identification of children at very low risk of clinically important traumatic brain injury (PECARN TBI).1 It is the largest, but hardly the only, entrant in the field. The United Kingdom contributes the children’s head injury algorithm for the prediction of important clinical events (CHALICE), and Canada contributes the Canadian assessment of tomography for childhood head injury (CATCH).2,3
These instruments arose from recognition of the increasing use of computed tomography (CT) in children as well as harms from radiation often exceeding the risks from missed injuries. These decision instruments, PECARN TBI in particular, have been widely promoted and used since their introduction.
The question remains, however, are they really necessary? As previously discussed, decision instruments are rarely validated against usual practice.4 More frequently, the best comparison for their performance comes from the derivation cohort. Looking at the original studies, the added value of these decision instruments remains a matter of reasonable question. The derivation of CHALICE is anachronistic enough to not be relevant, with a 3 percent rate of CT and a 23 percent rate of skull X-ray. In PECARN TBI, the base rate for imaging is 35 percent; in CATCH, 53 percent. In these contexts, it is less impressive that PECARN TBI classifies only 53 to 58 percent of the population as very low risk, while CATCH performs similarly, excluding just 48 percent.