PECARN Abdominal Trauma Rule Performs Well

January 7, 2019

Written by Clay Smith

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The PECARN rule for blunt abdominal trauma in children had high sensitivity, 99%, in this retrospective review. A prospective validation study would give us greater confidence to use this in clinical practice.

Why does this matter?
The PECARN head injury rule is widely used to reduce head CT scanning in children. Less known is the PECARN rule for blunt abdominal trauma (BAT). We covered this as part of our landmark article series. Two rules have been derived, and this study was based on the latter derivation study.

Using brains not CT scanners
This was a retrospective study including 133 children from a single institution’s pediatric trauma registry. They found the sensitivity of the PECARN rule for clinically important intra-abdominal injury (CIIAI) was 99%. CIIAI was defined identically to the PECARN study and consisted of abdominal injury resulting in: “death, therapeutic intervention at laparotomy, angiographic embolization of intra-abdominal arterial bleeding, blood transfusion for intra-abdominal hemorrhage, and administration of intravenous fluids for two or more nights for pancreatic or gastrointestinal injuries.” The only patient missed likely had another extra-abdominal reason to have needed transfusion. The rule this study used was based on 7 aspects.

PECARN rule for BAT:

• no evidence of abdominal wall trauma or seat belt sign

• Glasgow Coma Scale score greater than 13

• no abdominal tenderness

• no evidence of thoracic wall trauma

• no complaints of abdominal pain

• no decreased breath sounds

• no vomiting

In the original derivation study, sensitivity was 97%, NPV 99.9%. This study showed that application of this rule would have correctly identified all but one patient with CIIAI. There is always concern in retrospective studies for misclassification, missing data, or conflicting data on chart review. Plus, the definition of CIIAI was very specific and does not encompass all intra-abdominal injuries that may occur. Also, this study was limited to patients who had the disease of interest – severe abdominal trauma requiring intervention. In actual practice, we are starting with an undifferentiated group of injured children, which could alter the performance characteristics of the rule. That’s why a prospective validation study is so important. This is a step in the right direction, and it is worth considering the PECARN BAT rule when making imaging decisions. Just be wary.

By the way, I must give a shout out to my coworkers who wrote this! Congrats!

Another Spoonful
Pediatric EM Morsels covered the original derivation study.

Source
Springer E, Frazier SB, Arnold DH, Vukovic AA. External validation of a clinical prediction rule for very low risk pediatric blunt abdominal trauma. Am J Emerg Med. 2018 Nov 23. pii: S0735-6757(18)30943-4. doi: 10.1016/j.ajem.2018.11.031. [Epub ahead of print]

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