超声测量视神经鞘直径与颅内压增高的相关性研究

摘要

目的：探讨超声测量视神经鞘直径（optic nerve sheath diameter，ONSD）对诊断颅内压（intracranial pressure，ICP）增高患者的有效性和可行性。方法采用前瞻性临床试验，选取2014-09～2015-11在本院行去颅骨瓣减压手术并在术中植入有创 ICP 监测装置的患者60例，术后回到重症监护室（ICU）后行床旁超声经眼眶检测眼球后3 mm处ONSD。通过直接监测到的ICP与超声测得的视神经鞘直径利用统计学软件计算其相关性，并利用ROC曲线探究诊断ICP增高的最佳阈值。结果超声测量ONSD与ICP有显著相关性，R=0.778（95%CI 0.57～0.87，P＜0.0001）， ROC曲线下面积AUC为0.964（95% CI 0.923～1.000）。当取ONSD为4.8 mm作为诊断ICP增高的临界值时，其诊断的敏感度为91%（30/33），特异度为89%（24/27），阳性预测值为91%（30/33），阴性预测值为89%（24/27）；当取ONSD为5.0 mm作为诊断ICP增高的临界值时，其诊断的敏感度为79%（26/33），特异度为96%（26/27），阳性预测值为96%（26/27），阴性预测值为79%（26/33）。结论 ONSD随着颅内压增高而增大，但ONSD与ICP之间并非呈线性关系。当ONSD ≥4.8 mm时可以诊断ICP增高。ONSD能够较好地反映ICP增高水平，是一种方便、快捷、无创的新的检测手段，具有一定的临床应用价值。%Objective To investigate the effectiveness and feasibility of optic nerve sheath di⁃ameter(ONSD)measured by ultrasound in detection/diagnosis of increased intracranial pressure(ICP). Methods This was a prospective double-blinded observational study. From September 2014 to Novem⁃ber 2015, 60 patients with brain injury were included. Each patient was performed decompressive crani⁃ectomy and implanted invasive intracranial pressure detector at the same time. After the operation was done and the patient went back to Intensive Care Unit, we used the bedside ultrasound to measure 3 mm behind the retina as optic nerve sheath diameter. The correlation between ICP and ONSD was assessed by SPSS 19.0. The diagnostic performance of ONSD was determined by recelver operating curve(ROC). Results There were 60 patients in our study which included 32 males and 28 females. The average age was 49.2(18 ~ 80). Diagnoses included intracerebral hemorrhage(31), traumatic brain injury(18), acute cerebral infarction(5), extradural hemorrhage(6). Spearman rank correlation coefficient of ON⁃SD and ICP was 0.778(95% CI 0.57 ~ 0.87, P<0.0001), demonstrating a significant correlation. A ROC curve was drawn to determine the optimal cut off value to distinguish an ICP greater than 20 mmHg. The area under the receiver operator characteristic curve(AUC)was 0.964(95%CI 0.923 ~1.000). Optimal cut-off of ONSD for detection of elevated ICP(>20 mm Hg)was 4.8 mm, with sensitivity 91%(30/33), specificity 89%(24/27). The positive predictive value was 91%(30/33), negative pre⁃dictive value was 89%(24/27). When ONSD was over 5.0 mm, the sensitivity was 79%(26/33), speci⁃ficity was 96%(26/27), with positive predictive value 96%(26/27)and negative predictive value 79%(26/33). Conclusion The results indicated that ONSD increased along with the rise of ICP, which is consistent with many previous studies. But the relationship between ONSD and ICP is not purely linear. Optimal ONSD for detection of ICP>20 mmHg was ≥4.8 mm. In conclusion, ONSD measure⁃ment is a non-invasive, accurate, convenient and efficient method to identify the rise of ICP. Although this method has high application value, it cannot displace other detection methods.