Objectives: 

To compare the diagnostic accuracy of the ultrasonography-guided optic nerve sheath diameter with transcranial Doppler-guided middle cerebral artery flow indices against the gold standard invasive intraparenchymal intracranial pressure values in children.

Design: 

A single-center prospective cohort study.

Setting: 

PICU of a tertiary care teaching hospital in North India.

Patients: 

Eligible children (2–12 yr) are admitted to ICU and are undergoing intracranial pressure monitoring using an intraparenchymal catheter. Observations with a parallel measured intracranial pressure greater than or equal to 20 mm Hg were included as case-observations. Children with an invasive intracranial pressure of less than or equal to 15 mm Hg were taken as neurologic-control-observations and healthy children served as healthy-control-observations.

Interventions: 

The horizontal and vertical diameters of the optic nerves were measured, and averages were calculated and compared. Middle cerebral artery flow indices (pulsatility index and resistive index) were measured bilaterally and averages were calculated and compared in the three groups. Twenty-two measurements of optic nerve sheath diameter were assessed by two different observers in quick succession for interrater reliability.

Measurements and Main Results: 

A total of 148 observations were performed in 30 children. Four observations were excluded (intracranial pressure between 16 and 19 mm Hg). Of the 144 observations, 106 were case-observations and 38 were neurologic-control-observations. Additional 66 observations were healthy-control-observations. The mean optic nerve sheath diameter was 5.71 ± 0.57 mm in the case-observations group, 4.21 ± 0.66 mm in the neurologic-control-observations group, and 3.71 ± 0.27 mm in the healthy-control-observations group (p < 0.001 for case-observations vs neurologic-control-observations/healthy-control-observations). The mean pulsatility index in case-observations was 0.92 ± 0.41 compared with controls 0.79 ± 0.22 (p = 0.005) and the mean resistive index was 0.56 ± 0.13 in case-observations compared with 0.51 ± 0.09 (p = 0.007) in controls (neurologic-control-observations and healthy-control-observations). For the raised intracranial pressure defined by intracranial pressure greater than or equal to 20 mm Hg, the area under the curve for optic nerve sheath diameter was 0.976, while it was 0.571 for pulsatility index and 0.579 for resistive index. Furthermore, the optic nerve sheath diameter cutoff of 4.0 mm had 98% sensitivity and 75% specificity for raised intracranial pressure, while the pulsatility index value of 0.51 had 89% sensitivity and 10% specificity by middle cerebral artery flow studies. The sensitivity and specificity of 0.40 resistive index value in the raised intracranial pressure were 88% and 11%, respectively. Kendall correlation coefficient between intracranial pressure and optic nerve sheath diameter, pulsatility index, and resistive index was 0.461, 0.148, and 0.148, respectively. The Pearson correlation coefficient between two observers for optic nerve sheath diameter, pulsatility index, and resistive index was 0.98, 0.914, and 0.833, respectively.

Conclusions: 

Unlike transcranial Doppler-guided middle cerebral artery flow indices, ultrasonography-guided optic nerve sheath diameter was observed to have a good diagnostic accuracy in identifying children with an intracranial pressure of greater than or equal to 20 mm Hg.

中文翻译：

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视神经鞘管直径和经颅多普勒作为检测儿童颅内压升高的非侵入性工具的评估

目标： 

为了比较超声引导下视神经鞘管直径与经颅多普勒引导下大脑中动脉血流指数对儿童金标准浸润实质性颅内压的诊断准确性。

设计： 

单中心前瞻性队列研究。

设置： 

印度北部一家三级护理教学医院的PICU。

耐心： 

符合条件的儿童（2至12岁）被送入ICU，并使用实质内导管进行颅内压监测。病例观察包括平行测量的颅内压大于或等于20 mm Hg的观察结果。侵入性颅内压低于或等于15 mm Hg的儿童被视为神经控制观察，健康儿童被视为健康控制观察。

干预措施： 

测量视神经的水平和垂直直径，并计算平均值并进行比较。双侧测量大脑中动脉血流指数（搏动指数和抵抗指数），并计算三组平均值并进行比较。由两位不同的观察者快速连续评估了22条视神经鞘管的直径，以确保其间的可靠性。

测量和主要结果： 

在30名儿童中进行了148次观察。排除了四个观察结果（颅内压在16至19毫米汞柱之间）。在144项观察中，有106例是病例观察，有38例是神经控制观察。其他66个观察结果是健康对照观察结果。病例观察组平均视神经鞘直径为5.71±0.57 mm，神经控制观察组为4.21±0.66 mm，健康对照观察组为3.71±0.27 mm（病例p <0.001 -观察与神经控制观察/健康控制观察）。病例观察中的平均搏动指数为0.92±0.41，而对照组为0.79±0.22（p= 0.005），病例观察的平均电阻指数为0.56±0.13，而电阻率为0.51±0.09（p= 0.007）在对照中（神经控制观察和健康对照观察）。对于由大于或等于20 mm Hg的颅内压定义的升高的颅内压，视神经鞘管直径曲线下的面积为0.976，而搏动指数为0.571，电阻指数为0.579。此外，通过大脑中动脉血流研究，4.0 mm的视神经鞘管直径截断对颅内压升高具有98％的敏感性和75％的特异性，而0.51的搏动指数值对89％的颅内压具有89％的敏感性和10％的特异性。颅内压升高时，电阻率为0.40的敏感性和特异性分别为88％和11％。颅内压与视神经鞘管直径，搏动指数，电阻指数分别为0.461、0.148和0.148。两名观察者的视神经鞘管直径，搏动指数和电阻指数之间的皮尔逊相关系数分别为0.98、0.914和0.833。

结论： 

与经颅多普勒引导的大脑中动脉血流指数不同，超声检查引导的视神经鞘管直径在识别颅内压大于或等于20 mm Hg的儿童时具有良好的诊断准确性。