新たに導出された予測ルールを用いれば、頭部外傷後の子どものうち臨床的に重大な外傷性脳損傷（ciTBI）のリスクが低い患児を同定して、不要なCT検 査を回避できることが、アメリカCalifornia大学医学部Davis校救急医療部のNathan Kuppermann氏らPECARN（Pediatric Emergency Care Applied Research Network）の研究グループによって明らかにされた。外傷性脳損傷は子どもの死亡および身体障害の主要原因であり、脳手術など緊急の介入を要する ciTBIの患児を迅速に同定する必要がある。頭部外傷小児に対するCT検査は、放射線被曝による悪性腫瘍のリスクがあるため、CTが不要な低リスク例を 同定する方法の確立が切望されていた。Lancet誌2009年10月3日号（オンライン版2009年9月15日号）掲載の報告。(ケアネット)
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 >or=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 1176/1176 (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 3798/3800 (99.95%, 99.81-99.99) and sensitivity of 61/63 (96.8%, 89.0-99.6). 446 (20.1%) 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.
Kuppermann N, Holmes JF,et al.: Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study. Lancet. 2009 Oct;374(9696):1160-70.
