Mower William R, Gupta Malkeet, Rodriguez Robert, Hendey Gregory W
UCLA Department of Emergency Medicine, Ronald Reagan UCLA Medical Center, Los Angeles, California, United States of America.
Antelope Valley Hospital Emergency Department, Lancaster, California, United States of America.
PLoS Med. 2017 Jul 11;14(7):e1002313. doi: 10.1371/journal.pmed.1002313. eCollection 2017 Jul.
Clinicians, afraid of missing intracranial injuries, liberally obtain computed tomographic (CT) head imaging in blunt trauma patients. Prior work suggests that clinical criteria (National Emergency X-Radiography Utilization Study [NEXUS] Head CT decision instrument [DI]) can reliably identify patients with important injuries, while excluding injury, and the need for imaging in many patients. Validating this DI requires confirmation of the hypothesis that the lower 95% confidence limit for its sensitivity in detecting serious injury exceeds 99.0%. A secondary goal of the study was to complete an independent validation and comparison of the Canadian and NEXUS Head CT rules among the subgroup of patients meeting the inclusion and exclusion criteria.
We conducted a prospective observational study of the NEXUS Head CT DI in 4 hospital emergency departments between April 2006 and December 2015. Implementation of the rule requires that patients satisfy 8 criteria to achieve "low-risk" classification. Patients are excluded from "low-risk" classification and assigned "high-risk" status if they fail to meet 1 or more criteria. We examined the instrument's performance in assigning "high-risk" status to patients requiring neurosurgical intervention among a cohort of 11,770 blunt head injury patients. The NEXUS Head CT DI assigned high-risk status to 420 of 420 patients requiring neurosurgical intervention (sensitivity, 100.0% [95% confidence interval [CI]: 99.1%-100.0%]). The instrument assigned low-risk status to 2,823 of 11,350 patients who did not require neurosurgical intervention (specificity, 24.9% [95% CI: 24.1%-25.7%]). None of the 2,823 low-risk patients required neurosurgical intervention (negative predictive value [NPV], 100.0% [95% CI: 99.9%-100.0%]). The DI assigned high-risk status to 759 of 767 patients with significant intracranial injuries (sensitivity, 99.0% [95% CI: 98.0%-99.6%]). The instrument assigned low-risk status to 2,815 of 11,003 patients who did not have significant injuries (specificity, 25.6% [95% CI: 24.8%-26.4%]). Significant injuries were absent in 2,815 of the 2,823 patients assigned low-risk status (NPV, 99.7% [95% CI: 99.4%-99.9%]). Of our patients, 7,759 (65.9%) met the inclusion and exclusion criteria of the Canadian Head CT rule, including 111 patients (1.43%) who required neurosurgical intervention and 306 (3.94%) who had significant intracranial injuries. In our study, the Canadian criteria for neurosurgical intervention identified 108 of 111 patients requiring neurosurgical intervention to yield a sensitivity of 97.3% (95% CI: 92.3%-99.4%) and exhibited a specificity of 58.8% (95% CI: 57.7%-59.9%). The NEXUS rule, when applied to this same cohort, identified all 111 patients requiring neurosurgical intervention, yielding a sensitivity of 100% (95% CI: 96.7%-100.0%) with a specificity of 32.6% (95% CI: 31.5%-33.6%). Our study found that the Canadian medium-risk factors identified 301 of 306 patients with significant injuries (sensitivity = 98.4%; 95% CI: 96.2%-99.5%), while the NEXUS rule identified 299 of these patients (sensitivity = 97.7%; 95% CI: 95.3%-99.1%). In our study, the Canadian medium-risk rule exhibited a specificity of 12.3% (95% CI: 11.6%-13.1%), while the NEXUS rule exhibited a specificity of 33.3% (95% CI: 32.3%-34.4%). Limitations of the study may arise from application of the rule by different clinicians in different environments. Clinicians may vary in their interpretation and application of the instrument's criteria and risk assignment and may also vary in deciding which patients require intervention. The instrument's specificity is also subject to spectrum bias and may change with variations in the proportion of "low-risk" patients seen in other centers.
The NEXUS Head CT DI reliably identifies blunt trauma patients who require head CT imaging and could significantly reduce the use of CT imaging.
临床医生因担心漏诊颅内损伤，对钝性创伤患者普遍进行头颅计算机断层扫描（CT）检查。先前的研究表明，临床标准（国家急诊X线摄影利用研究[NEXUS]头颅CT决策工具[DI]）能够可靠地识别出有重要损伤的患者，同时排除损伤，并使许多患者无需进行影像学检查。验证该决策工具需要证实这样一个假设，即其检测严重损伤的敏感性的95%置信区间下限超过99.0%。该研究的第二个目标是在符合纳入和排除标准的患者亚组中，对加拿大和NEXUS头颅CT规则进行独立验证和比较。
我们于2006年4月至2015年12月期间在4家医院急诊科对NEXUS头颅CT决策工具进行了一项前瞻性观察研究。实施该规则要求患者满足8条标准才能实现“低风险”分类。如果患者不符合1条或更多标准，则被排除在“低风险”分类之外，并被赋予“高风险”状态。我们在11770例钝性颅脑损伤患者队列中，研究了该工具在将“高风险”状态分配给需要神经外科干预的患者方面的表现。NEXUS头颅CT决策工具将420例需要神经外科干预的患者中的420例判定为高风险状态（敏感性，100.0%[95%置信区间（CI）：99.1%-100.0%]）。该工具将11350例不需要神经外科干预的患者中的2823例判定为低风险状态（特异性，24.9%[95%CI：24.1%-25.7%]）。2823例低风险患者中无一例需要神经外科干预（阴性预测值[NPV]，100.0%[95%CI：99.9%-100.0%]）。该决策工具将767例有严重颅内损伤的患者中的759例判定为高风险状态（敏感性，99.0%[95%CI：98.0%-99.6%]）。该工具将11003例无严重损伤的患者中的2815例判定为低风险状态（特异性，25.6%[95%CI：24.8%-26.4%]）。在被判定为低风险状态的2823例患者中，2815例无严重损伤（NPV，99.7%[95%CI：99.4%-99.9%]）。我们的患者中，7759例（65.9%）符合加拿大头颅CT规则的纳入和排除标准，其中包括111例（1.43%）需要神经外科干预的患者和306例（3.94%）有严重颅内损伤的患者。在我们的研究中，加拿大神经外科干预标准识别出111例需要神经外科干预的患者中的108例，敏感性为97.3%（95%CI：92.3%-99.4%），特异性为58.8%（95%CI：57.7%-59.9%）。当将NEXUS规则应用于同一队列时，识别出所有111例需要神经外科干预的患者，敏感性为100%（95%CI：96.7%-100.0%），特异性为32.6%（95%CI：31.5%-33.6%）。我们的研究发现，加拿大中度风险因素识别出306例有严重损伤患者中的301例（敏感性=98.4%；95%CI：96.2%-99.5%），而NEXUS规则识别出其中299例（敏感性=97.7%；95%CI：95.3%-99.1%）。在我们的研究中，加拿大中度风险规则的特异性为12.3%（95%CI：11.6%-13.1%），而NEXUS规则的特异性为33.3%（95%CI：32.3%-34.4%）。该研究的局限性可能源于不同临床医生在不同环境中应用该规则。临床医生对该工具标准和风险分配的解释和应用可能存在差异，在决定哪些患者需要干预方面也可能存在差异。该工具的特异性也可能受到谱偏倚的影响，并且可能会随着其他中心“低风险”患者比例的变化而改变。
NEXUS头颅CT决策工具能够可靠地识别需要进行头颅CT检查的钝性创伤患者，并可显著减少CT检查的使用。
