Validation of the Pediatric NEXUS II Head Computed Tomography Decision Instrument for Selective Imaging of Pediatric Patients with Blunt Head Trauma

Acad Emerg Med. 2018 Jul;25(7):729-737. doi: 10.1111/acem.13431. Epub 2018 Jun 8.


Background: Data suggest that clinicians, when evaluating pediatric patients with blunt head trauma, may be overordering head computed tomography (CT). Prior decision instruments (DIs) aimed at aiding clinicians in safely forgoing CTs may be paradoxically increasing CT utilization. This study evaluated a novel DI that aims for high sensitivity while also improving specificity over prior instruments.

Methods: We conducted a planned secondary analysis of the NEXUS Head CT DI among patients less than 18 years old. The rule required patients satisfy seven criteria to achieve "low-risk" classification. Patients were assigned "high-risk" status if they fail to meet one or more criteria. Our primary outcome was the ability of the rule to identify all patients requiring neurosurgical intervention.

Results: The study enrolled 1,018 blunt head injury pediatric patients. The DI assigned high-risk status to 27 of 27 patients requiring neurosurgical intervention (sensitivity = 100.0%, 95% confidence interval [CI] = 87.2%-100%]). The instrument assigned low-risk status to 330 of 991 patients who did not require neurosurgical intervention (specificity = 33.3%, 95% CI = 30.3%-36.3%). None of the 991 low-risk patients required neurosurgical intervention (negative predictive value [NPV] = 100%, 95% CI = 99.6%-100%). The DI correctly assigned high-risk status to 48 of the 49 patients with significant intracranial injuries, yielding a sensitivity of 98.0% (95% CI = 89.1%-99.9%). The instrument assigned low-risk status to 329 of 969 patients who did not have significant injuries to yield a specificity of 34.0% (95% CI = 31.0%-37.0%). Significant injuries were absent in 329 of the 330 patients assigned low-risk status to yield a NPV of 99.7% (95% CI = 98.3%-100%).

Conclusions: The Pediatric NEXUS Head CT DI reliably identifies blunt trauma patients who require head CT imaging and could significantly reduce the use of CT imaging.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Validation Study

MeSH terms

  • Adolescent
  • Child
  • Child, Preschool
  • Decision Support Techniques*
  • Female
  • Head Injuries, Closed / diagnostic imaging*
  • Humans
  • Injury Severity Score
  • Male
  • Prospective Studies
  • Risk Assessment
  • Sensitivity and Specificity
  • Tomography, X-Ray Computed / statistics & numerical data*
  • Unnecessary Procedures