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PECARN Pediatric Head Injury/Trauma Algorithm

• Introduction
• Points & Pearls
• Why and When to Use, and Next Steps
• Calculator Review Author
• Critical Actions
• Evidence Appraisal
• Calculator Creator
• References
• Selected Abbreviations

Introduction

The PECARN Pediatric Head Injury Prediction Rule is a well-validated clinical decision aid that allows physicians to safely rule out the presence of clinically important traumatic brain injuries.

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Points & Pearls

• The Pediatric Emergency Care Applied Research Network (PECARN) consortium produced the largest study, to date, aiming to derive and validate clinical prediction rules to identify children with very low risk of clinically important traumatic brain injury (ciTBI) following blunt head trauma, who would not require imaging. ciTBI was chosen as the primary outcome because it is clinically driven and accounts for the imperfect test characteristics of computed tomography (CT).
• In the group of patients aged < 2 years, the rule was 100% sensitive.
• In the group of patients aged > 2 years, the rule had 96.8% sensitivity.
• In those aged < 2 years with a Glasglow Coma Scale (GCS) score of 14, altered mental status, or palpable skull fracture, risk was 4.4%, and CT imaging is recommended.
• Risk with any of the remaining predictors was 0.9%, and < 0.02% with no predictors.
• In those aged > 2 years with GCS score of 14, altered mental status, or signs of basilar skull fracture, risk was 4.3%, and CT imaging is recommended.
• Risk with any of the remaining 4 predictors was 0.9%, and < 0.05% with no predictors. The PECARN Rule outperformed both the CHALICE (Children's Head injury ALgorithm for the prediction of Important Clinical Events) and CATCH (Canadian Assessment of Tomography for Childhood Head injury) clinical decision aids in external validation studies.
• Although it was the largest trial of its kind, the PECARN study had low rates of traumatic brain injury (TBI) on head CT (5.2%) and even lower rates of ciTBI (0.9%), suggesting that overall TBI in children is rare. Head CTs were obtained in approximately 35% of patients, lower than the average estimate of 50%.

Why and When to Use, and Next Steps

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Critical Actions

ciTBI was a rare event (0.9%) and neurosurgical intervention was even more rare (0.1%). Over 50% of each age cohort did not meet any predictors, and CT imaging is not indicated for the vast majority of these patients, as risk of ciTBI was exceedingly low. Risk of ciTBI was > 4% with either of the 2 higher-risk predictors in each age cohort, and imaging is recommended.

For the remaining 4 lower-risk predictors in each cohort, the risk of ciTBI is approximately 0.9% per predictor, and CT imaging is indicated rather than observation. Judgment may be based on clinical experience, single versus multiple findings, signs of clinical deterioration during the observation period, patient age, and/or parental preference.

Evidence Appraisal

The original PECARN trial included 42,412 children aged < 18 years presenting to one of the 25 North American PECARN-affiliated emergency departments. There were 33,785 patients in the derivation cohort (8502 of whom were aged < 2 years) and 8627 in the validation cohort (2216 of whom were aged < 2 years).

CT scans were performed at the physician’s dis-cretion in 35.3%, while medical records, telephone surveys, and county morgue records were used to assess for cases of missed ciTBI in those discharged without imaging. The potential for CT reduction quoted above is likely underestimated, given that CT utilization in this study (35.3%) was significantly lower than the estimated average in North American emergency departments (50%).

TBI occurred in 5.2% of patients. Nine percent of patients were admitted to the hospital. ciTBI occurred in 0.9% of the cohort, neurosurgery was performed in 0.1% of the overall cohort, and 0 patients died. In patients aged < 2 years who were negative for any PECARN risk factor, the aid was 100% sensitive (95% confidence interval [CI], 86.3-100) with a negative predictive value (NPV) of 100% (95% CI, 99.7-1000) for ruling out ciTBI in the validation cohort. In patients aged > 2 years who were negative for any PECARN risk factor, the aid was 96.8% sensitive (95% CI, 89.0-99.6) with 99.95% NPV (95% CI, 99.8-99.99) for ruling out ciTBI in the validation cohort.

External validation studies have demonstrated sensitivity of 100% for ciTBI and any injury requiring neurosurgery. The algorithm has reasonable specificity (53%-60%), considering its extremely high sensitivity.

Sixty of 376 patients (15.9%) with ciTBI underwent neurosurgery, 8 patients (2.1%) with ciTBI were intubated > 24 hours, and 0 patients died.

As a result of the infrequency of ciTBI, the lower bounds of the CIs of sensitivity started at 86% and 89%, respectively, for the cohorts aged < 2 years and > 2 years. The NPV CIs very closely approximated 100%.

The PECARN Rule has now been externally validated in 2 separate studies. One trial of 2439 children in 2 North American and Italian centers found the PECARN Rule to be 100% sensitive for ruling out ciTBI in both age cohorts. The rates of 0.8% (19/2439) of patients with ciTBI and 0.08% (2/2439) of patients requiring neurosurgery were similar to the rates in the PECARN trial.

A second trial at a single United States emergency department of 1009 patients aged < 18 years prospectively compared the PECARN Rule to 2 other pediatric head CT decision aids, CHALICE and CATCH, as well as to physician estimates and physician practice. In this sample, 2% (21/1009) of patients had ciTBI and 0.4% (4/1009) of patients needed neurosurgery. Again, the PECARN Rule was found to be 100% sensitive for identifying ciTBI.

The PECARN Rule outperformed both the CHALICE and CATCH decision aids, which were 91% and 84% sensitive for ciTBI, respectively). Although the goal was to rule out those with very low risk of ciTBI, the PECARN Rule also performed well to rule out TBI on head CT. In patients aged < 2 years, sensitivity and NPV were 100% for TBI on CT, with narrow CIs. In patients aged > 2 years, sensitivity was 98.4% and NPV was 94% for TBI on CT, with relatively narrow confidence intervals.

Two PECARN Rule subgroup analyses attempted to further risk-stratify patients with single predictors (eg, isolated scalp hematoma in patients aged < 2 years). ciTBI was too uncommon to apply age, hematoma size, or hematoma location predictors. There were several non–statistically significant trends for higher rates of TBI on head CT that may affect imaging tendencies (eg, age < 3 months, nonfrontal hematoma, and large size).

Another subanalysis of those with isolated vom-iting (eg, no other PECARN predictors) reiterated the parent study results. In the cohort of patients aged > 2 years, there was a low rate of TBI on head CT (3.2%, 26 of 806 patients) and an even lower rate of ciTBI (0.7%, 10 of 1501 patients), so observation rather than emergent imaging is indicated in the majority of these patients. Number of vomiting episodes and timing of episodes was not helpful in predicting ciTBI or TBI on head CT, as there was a non–statistically significant counterintuitive trend towards less ciTBI/TBI on CT with more episodes.

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Nate Kupperman, MD, MPH

References

Original/Primary Reference

• Holmes JF, Dayan PS, Hoyle JD Jr, et al. Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study. Lancet. 2009;374(9696):1160-1170.

Validation Reference

• Schonfeld D, Bressan S, Da Dalt L, et al. Pediatric Emergency Care Applied Research Network head injury clinical prediction rules are reliable in practice. Arch Dis Child. 2014;99(5):427-431.

Other References

• Easter JS, Bakes K, Dhaliwal J, et al. Comparison of PECARN, CATCH, and CHALICE rules for children with minor head injury: a prospective cohort study. Ann Emerg Med. 2014;64(2):145-152, 152.e1-152.e5.
• Brenner D, Elliston C, Hall E, Berdon W. Estimated risks of radiation-induced fatal cancer from pediatric CT. AJR Am J Roentgenol. 2001;176(2):289-296.
• Dayan PS, Holmes JF, Atabaki S, et al. Association of traumatic brain injuries with vomiting children with blunt head trauma. Ann Emerg Med. 2014;63(6): 657-665.
• Dayan PS, Holmes JF, Schutzman S, et al. Risk of traumatic brain injuries in children younger than 24 months with isolated scalp hematomas. Ann Emerg Med. 2014;64(2):153-162.
• Hess EP, Wyatt KD, Kharbanda AB, et al. Effectiveness of the head CT choice decision aid in parents of children with minor head trauma: study protocol for a multicenter randomized trial. Trials. 2014;15:253.

Selected Abbreviations