For the >2 year old group in the PECARN study, you're correct about the sensitivity of the rule, but sensitivity is not the best approximation of bedside utility (or harm) for a test (because of the low prevalence of ciTBI, and how prevalence goes hand-in-hand with predictive values, etc.). Number needed to harm is probably the most helpful way to think about it -- how many patients with no risk factors according to the rule would be harmed if the rule were strictly applied? For their population, this was approximately 2,000.
From: Pediatric Emergency Medicine Discussion List [[log in to unmask]] on behalf of Jay Fisher [[log in to unmask]]
Sent: Monday, November 05, 2012 9:13
To: [log in to unmask]
Subject: Re: Teenager with two days of headache
I am surprised by everyone's surprise.
We see patients with a normal neuro exam and positive head CTs with a low
but steady frequency.
We had a school age girl with just headache with a spontaneous ICH a few
years ago and a walking, talking teenager with an operable EDH just last
year. He had fallen off a bike with a brief LOC two days prior.
All the head injury/ CT research demonstrates that our standard decision
rules will miss ICH at a steady clip.
Even the PECARN data had a sensitivity of 96.8% for clinically important
ICH. That means one in thirty important injury gets missed. The confidence
interval (which is what you should really be looking at) went as low as 89%!
That means the best research ever on this topic says our decision rule,
within statistical confidence, could miss as many as 1 in 10 clinically
My experience is consistent with this.
Jay Fisher MD
Children's Hospital of NV
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