Elsevier

The Lancet

Volume 374, Issue 9696, 3–9 October 2009, Pages 1160-1170
The Lancet

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Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study

https://doi.org/10.1016/S0140-6736(09)61558-0Get rights and content

Summary

Background

CT imaging of head-injured children has risks of radiation-induced malignancy. Our aim was to identify children at very low risk of clinically-important traumatic brain injuries (ciTBI) for whom CT might be unnecessary.

Methods

We enrolled patients younger than 18 years presenting within 24 h of head trauma with Glasgow Coma Scale scores of 14–15 in 25 North American emergency departments. We derived and validated age-specific prediction rules for ciTBI (death from traumatic brain injury, neurosurgery, intubation >24 h, or hospital admission ≥2 nights).

Findings

We enrolled and analysed 42 412 children (derivation and validation populations: 8502 and 2216 younger than 2 years, and 25 283 and 6411 aged 2 years and older). We obtained CT scans on 14 969 (35·3%); ciTBIs occurred in 376 (0·9%), and 60 (0·1%) underwent neurosurgery. In the validation population, the prediction rule for children younger than 2 years (normal mental status, no scalp haematoma except frontal, no loss of consciousness or loss of consciousness for less than 5 s, non-severe injury mechanism, no palpable skull fracture, and acting normally according to the parents) had a negative predictive value for ciTBI of 1175/1175 (100·0%, 95% CI 99·7–100 0) and sensitivity of 25/25 (100%, 86·3–100·0). 167 (24·1%) of 694 CT-imaged patients younger than 2 years were in this low-risk group. The prediction rule for children aged 2 years and older (normal mental status, no loss of consciousness, no vomiting, non-severe injury mechanism, no signs of basilar skull fracture, and no severe headache) had a negative predictive value of 3698/3698 (99·95%, 99·80–99·99) and sensitivity of 61/63 (96·8%, 89·0–99·6). 438 (19.7%) of 2223 CT-imaged patients aged 2 years and older were in this low-risk group. Neither rule missed neurosurgery in validation populations.

Interpretation

These validated prediction rules identified children at very low risk of ciTBIs for whom CT can routinely be obviated.

Funding

The Emergency Medical Services for Children Programme of the Maternal and Child Health Bureau, and the Maternal and Child Health Bureau Research Programme, Health Resources and Services Administration, US Department of Health and Human Services.

Introduction

Traumatic brain injury is a leading cause of death and disability in children worldwide. In the USA, head trauma in individuals aged 18 years and younger results in about 7400 deaths, over 60 000 hospital admissions, and over 600 000 emergency department visits every year.1, 2 Children with clinically-important traumatic brain injury (ciTBI) needing acute intervention, especially neurosurgery, should be identified rapidly. CT is the reference standard for emergently diagnosing traumatic brain injuries, although some brain injuries are not seen on CT.3, 4 About 50% of children assessed in North American emergency departments for head trauma undergo CT5, 6 (Faul M, Centers for Disease Control and Prevention, personal communication). Between 1995 and 2005, CT use more than doubled.6, 7 Furthermore, many traumatic brain injuries identified on CT do not need acute intervention, and some are false positives or non-traumatic findings. Clinical studies using abnormal CT findings as the outcome measure for identifying children with traumatic brain injuries might promote excessive CT use. Children with apparently minor head trauma (Glasgow Coma Scale [GCS] scores of 14–15) are the group most frequently assessed. These children commonly undergo neuroimaging and account for 40–60% of those with traumatic brain injuries seen on CT.8, 9, 10, 11 Less than 10% of CT scans in children with minor head trauma, however, show traumatic brain injuries. Furthermore, injuries needing neurosurgery are very uncommon in children with GCS scores of 14–15.10, 11, 12, 13

Reduction of CT use is important because ionising radiation from CT scans can cause lethal malignancies.14, 15, 16 The estimated rate of lethal malignancies from CT is between 1 in 1000 and 1 in 5000 paediatric cranial CT scans, with risk increasing as age decreases.14, 15 Clear data for CT use, however, are unavailable, therefore resulting in substantial practice variation.17 Previous predictive models8, 10, 18, 19, 20 are limited by small sample sizes, no validation, and/or no independent assessment of preverbal children (<2 years of age). Therefore, creation and validation of accurate, generalisable prediction rules for identifying children at very low risk of ciTBI are needed. A systematic review21 of head CT prediction rules has recently emphasised the need for a large prospective study of children with minor head trauma to derive and validate a precise rule, and has specifically recommended deriving a separate rule for very young children.

Our aim was to derive and validate prediction rules for ciTBI to identify children at very low risk of ciTBI after blunt head trauma for whom CT might be unnecessary.

Section snippets

Patients and setting

We did a prospective cohort study of patients younger than 18 years with head trauma in 25 emergency departments of a paediatric research network.22 The study was approved by the Human Subjects Research Committee at each site with waiver of consent at some sites and verbal consent for telephone follow-up at others. We enrolled the derivation population from June, 2004, to March, 2006, and the validation population from March through September, 2006.

Inclusion and exclusion criteria

Children presenting within 24 h of head trauma

Results

Of 57 030 eligible patients, we enrolled 43 904 (77%; figure 1). Of 42 412 patients eligible for analysis, mean age was 7·1 years (SD 5·5) and 10 718 (25%) were younger than 2 years. The injury mechanisms were: fall from height (n=11 665, 27%), fall from ground level or ran into stationary object (n=7106, 17%), occupant in motor vehicle crash (n=3717, 9%), head struck by an object (n=3124, 7%), assault (n=2981, 7%), sport-related (n=2934, 7%), fall down the stairs (n=2858, 7%), bicycle

Discussion

We derived and validated prediction rules for ciTBIs in a large, diverse population of children with minor head trauma. The large sample size allowed the derivation and validation of separate rules for children younger than 2 years and aged 2 years and older. The two rules are simple and intuitive, consist of readily available findings, and have a very high negative predictive value for identifying children without ciTBIs for whom CT scans could be omitted. Among all children enrolled, those

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