Predictors Determine Need for CT in Kids

ACEP News
October 2009

Newly developed prediction rules could spare low-risk pediatric head trauma patients from having to undergo CT scans

By Elizabeth Mechatie
Elsevier Global Medical News

New prediction rules derived in a large prospective study of children and adolescents could identify which head trauma patients are at very low risk of serious traumatic brain injuries and thus do not routinely need a CT scan.

The prospective cohort study included 42,412 children and adolescents who presented to 25 emergency departments in North America within 24 hours of head trauma, with Glasgow Coma Scale scores of 14-15.

"We derived and validated highly accurate prediction rules for children at very low risk of [clinically important traumatic brain injuries] for whom CT scans should be avoided," concluded Dr. Nathan Kupperman, chair of the department of emergency medicine and pediatrics, University of California, Davis, and his associates. "Application of these rules could limit CT use, protecting children from unnecessary radiation risks."

The study was published online in the Lancet (doi:10.1016/ S0140-6736[09]61558-0). The investigators are part of the Pediatric Emergency Care Applied Research Network (PECARN).

Children and adolescents with a GCS score of 14 or 15 and with apparently minor trauma account for about 98% of the pediatric patients seen in EDs for head trauma--and present a conundrum for clinicians, Dr. Kupperman said in an interview. Application of the prediction rules to the very low risk population would immediately eliminate 20%-25% of the unnecessary CT scans, he noted.

Because the study was so large, he added, it was possible for the first time to develop and validate a prediction rule for pre-verbal children, who can't describe the events or their symptoms--and are in the age group most sensitive to radiation.

The investigators defined clinically important traumatic brain injury (ciTBI) as death from traumatic brain injury, neurosurgery, intubation for more than 24 hours for traumatic brain injury, or hospital admission of at least 2 nights associated with traumatic brain injury on CT.

Of the study's 42,412 patients, 97% had a Glasgow Coma Scale of 15, 0.9% had ciTBI, and 0.1% underwent neurosurgery. A total of 14,969 of the study patients underwent CT scans (35%), and 5.2% of them had traumatic brain injuries on CT.

For children younger than 2 years (25% of the study population), the six predictors of low risk for ciTBI were:

  • Normal mental status.
  • No scalp hematoma except frontal. 
  • No loss of consciousness for 5 seconds or more. 
  • Mild or moderate mechanism of injury. 
  • No palpable or unclear skull fracture. 
  • Acting normally according to their parent.

When all six of those low-risk findings were present, the prediction rule correctly identified nearly 100% of the children younger than 2 years who did not have a ciTBI and included 24% of the children who had a CT scan performed.

For patients aged 2-18 years, the six predictors of low ciTBI risk were:

  • Normal mental status. 
  • No loss of consciousness. 
  • No vomiting.  
  • Mild or moderate mechanism of injury. 
  • No clinical signs of basilar skull fracture. 
  • No severe headache.

Following that prediction rule identified 99.95% of patients who did not have a ciTBI. This low-risk group included 20% of the patients in this age group who had CT scans performed.

The investigators noted that altered mental status and signs of skull fracture "are branch points in the prediction trees with high risks for ciTBI," and they recommended CT scans for children with either finding. Those with any of the other four predictors had a 0.9% risk of ciTBI; "decisions about CT use for this group should be based on other factors."

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