The Prognostic Value of Optic Nerve Sheath Diameter in Patients with Subarachnoid Hemorrhage

Background: We evaluated if the optic nerve sheath diameter (ONSD) on brain computed tomography (CT) could be used to predict neurological outcomes of patients with subarachnoid hemorrhage (SAH). Methods: This was a retrospective and observational study of adult patients with SAH admitted January 2012 through June 2017. Initial brain CT was performed within 12 hours from onset of SAH. Follow-up brain CT was performed within 24 hours from treatment of ruptured aneurysm. The primary outcome was neurological status upon six months later assessed with Glasgow Outcome Scale (GOS, 1 to 5). Results: Among 223 SAH patients, survival to discharge was identified in 202 (90.6%) patients. Of these survivors, 186 (83.4%) had good neurological outcomes (GOS of 3, 4 or 5). In this study, ONSDs in the poor neurological outcome group were significantly greater than those in the good neurological outcome group (all p < 0.01). Intracranial pressure (ICP) was monitored in 21 (9.4%) patients at that time of follow-up CT scanning. There was a linear correlation between average of both ONSD and ICP in simple correlation analysis (r = 0.525, p = 0.036). In ROC curve analysis for prediction of poor neurological outcome, ONSDs had considerable predictive values (C-statistics: 0.735 to 0.812). In addition, the performance of a composite of Hunt and Hess grade and ONSD was more associated with poor neurological outcomes than the use of each marker alone. Conclusions: The ONSDs measured on CT scanning may be beneficial for predicting neurological outcomes in SAH patients.研究背景：本研究旨在评估颅脑计算机断层扫描（computed tomography, CT）上的视神经鞘直径（optic nerve sheath diameter, ONSD）是否可用于预测蛛网膜下腔出血（subarachnoid hemorrhage, SAH）患者的神经功能预后。研究方法：本研究为回顾性观察性研究，纳入2012年1月至2017年6月期间收治的成年SAH患者。所有患者均于蛛网膜下腔出血发病后12小时内完成首次颅脑CT检查，并于破裂动脉瘤治疗后24小时内完成随访颅脑CT检查。本研究的主要结局为发病6个月后的神经功能状态，采用格拉斯哥预后量表（Glasgow Outcome Scale, GOS，1~5分）进行评估。研究结果：本研究共纳入223例SAH患者，其中202例（90.6%）患者存活至出院。在上述存活患者中，186例（83.4%）获得良好神经功能预后（GOS评分3、4或5分）。本研究显示，神经功能预后不良组患者的ONSD显著高于预后良好组（所有p<0.01）。在接受随访CT扫描的同期，共有21例（9.4%）患者接受了颅内压（intracranial pressure, ICP）监测。简单相关分析显示，双侧ONSD平均值与ICP平均值呈线性相关（r=0.525，p=0.036）。在预测神经功能预后不良的受试者工作特征曲线（Receiver Operating Characteristic curve, ROC）分析中，ONSD展现出可观的预测价值（C统计量：0.735~0.812）。此外，联合亨特-赫斯分级与ONSD的预测模型，相较于单独使用任一指标，与神经功能预后不良的相关性更为显著。研究结论：颅脑CT扫描测得的ONSD或可用于辅助预测SAH患者的神经功能预后。