To Örebro University

Background: Head trauma in children is a common cause for a visit to the A&E. Among the many children it is important to identify those at risk for developing a clinical important head injury (CITBI). The most important way of identifying the children at risk is to perform a CT scan of the head. There are reports indicating an induction of 1 cancer in children on 1000 – 5000 CT examinations. It is thus important to minimise the use of CT. In 2010 Osmond and co-workers introduced the Canadian Assessment of Tomography for Childhood Head injury: the CATCH rule (CATCH-R), with the aim of identifying those at most risk and to reduce the use of CT. The aim of this study is to validate the CATCH-R, using a large cohort of children.

Material Methods: The study is a cohort study based on the data set from: ‘‘Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study’’(Kuppermanns et al 2009). It includes data from more than 43000 children. The cohort was identified using the basal criteria in the CATCH-R, i.e. children with a GCS of 13 – 15. The CATCH-R was then used to identify children who should perform a CT.

Results: We identified 37277 children with a GCS of 13 – 15 of which 7774 fulfilled the criteria for MHI according to the CATCH-R. Of these 2699 had one or more risk factors, i.e. should perform a CT scan. In the CT group 117 children had a CITBI and in the non-CT group (n=5075) we identified 36 children with CITBI. At the division MHI and no-MHI according to the CATCH-R the NPV is 99.2 % (CI 99.1 – 99.2 %), and specificity 79.3% (CI 78.9 – 79.7). At the division MHI with risk factor/s and MHI without risk factor/s the NPV is 99.3% (CI 99.1 – 99.5 %), and specificity 66.1 % (CI 65.0 – 67.2 %).

Conclusion: It seems that using the CATCH-R the risk of not detecting a child with a CITBI is very small.