Written by Clay Smith
This prospective validation of the CATCH rule lacked sensitivity for use in clinical practice. By adding ≥4 episodes of vomiting to CATCH post hoc, sensitivity was markedly improved for neurosurgical intervention and predicting injury on CT. CATCH2 needs prospective validation.
Why does this matter?
The PECARN, CHALICE, and CATCH rules have all been compared. Physician gestalt seemed as good or better than all of them. How about this tweak of CATCH?
CATCH2 as CATCH can
This was a prospective validation of the CATCH decision instrument. They enrolled 4060 children with blunt head trauma and, “GCS 13–15 and loss of consciousness, amnesia, disorientation, persistent vomiting or irritability.” For the CATCH rule, sensitivity was 91.3% (95%CI, 72.0%–98.9%) for neurosurgical intervention and 97.5% (95%CI, 94.2%–99.2%) for brain injury on CT or no complications at 2 week follow up. This was a lackluster performance. They found that by adding a new component to CATCH, namely vomiting ≥4 times, that the sensitivity was greatly improved. The new iteration, dubbed CATCH2, had a sensitivity of 100% (95%CI, 85.2%–100%) for neurosurgical intervention and 99.5% (95%CI, 97.2%–100%) for brain injury on CT or no complications at 2 week follow up. Bear in mind, CATCH2 was applied to the original dataset post hoc, which means it was not prospectively validated. The new CATCH2 rule would have recommended 55% of children undergo head CT. By way of comparison, ~40% with a positive PECARN rule would need CT. Interestingly, physician gestalt led to a CT rate of just 8.3%. In short, CATCH had low enough sensitivity that I will not use it in practice; the refined CATCH2 rule looks promising but needs prospective validation.
Validation and refinement of a clinical decision rule for the use of computed tomography in children with minor head injury in the emergency department. CMAJ. 2018 Jul 9;190(27):E816-E822. doi: 10.1503/cmaj.170406.
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I owe a huge debt to EM Lit of Note for his analysis of the Lancet article and Annals of EM article.
Reviewed by Thomas Davis