Every country seems to have their own pediatric imaging rule for minor head trauma, featuring PECARN, CHALICE, and CATCH. Recently, a head-to-head-to-head comparison (no pun intended) found the clear winner was: clinical judgement in Australia and New Zealand. Adoption of any of the rules would not have reliably increased sensitivity, but all would dramatically increase imaging.
Now, what about adult head trauma? The same story of every-country-has-a-flavor seems to be the case, with the CT in Head Injury Patients rule, the New Orleans criteria, the Canadian CT Head rule, and the National Institute for Health and Care Excellence guideline. This time, we have the Dutch performing the comparison.
In this multicenter, observational study conducted in 2015 and 2016, the authors enrolled neurologically-intact patients aged greater than 16 years and presenting with blunt head trauma within 24 hours of injury. Clinical data with the elements necessary for each decision instrument were completed by treating clinicians and collected by study staff. Decisions to perform imaging were based on individual clinician discretion, but primarily based on the CHIP rule. Outcomes were ascertained by electronic record review.
There were 5,839 patients entered in their study database, 5,517 meeting eligibility criteria. At three centers, only patients undergoing CT were entered in the database, while the remaining six centers included a handful of patients who did not undergo CT. Obviously, this grossly limits the descriptive capacity of the study, as clearly a massive number of patients with minor head injury who did not undergo CT were not followed for outcomes.
Overall, 384 of the 3,742 patients undergoing CT had positive traumatic findings. Most were small skull fractures, but about half had intracranial bleeding of some variety or another, with a further 74 being judged potential neurosurgical lesions. The most sensitive of the decision instruments in this study was the New Orleans criteria, while NICE guidelines were the least. Of course, the New Orleans criteria also would have recommended CT in all but 189 patients, for a specificity of 4.2%.
Ultimately, there’s no clear “winner” in this study, and, unfortunately, there’s also no obvious superior “clinician judgement” comparison lurking. The underlying rate of imaging was effectively the same as CHIP, as this was the national guideline in the Netherlands at the time of the study. Whether this is the “best” depends on tolerance for risk and the reliability of their estimate of “potential neurosurgical lesion”. Then, regardless of the decision instrument chosen, each still recommends imaging in thousands of patients in order to pick up the few with positive findings. Considering data from children, it seems we ought to be able to do much better – but current practice does not appear to be moving in that direction.
“External validation of computed tomography decision rules for minor head injury: prospective, multicentre cohort study in the Netherlands”
https://www.bmj.com/content/362/bmj.k3527