Correlation of Optic Nerve Sheath Diameter with Direct Measurement of Intracranial Pressure through an External Ventricular Drain

Abstract

BackgroundEarly diagnosis and management of raised intracranial pressure (ICP) is essential for preventing brain damage and even death. Invasive monitoring is the gold standard to measure raised ICP but it may not be feasible in a heterogeneous group of patients. Noninvasively, a simple bedside ocular ultrasound can detect elevated ICP. The aim of our study was to evaluate the correlation between optic nerve sheath diameter (ONSD) and direct ICP measurements and to determine sensitivity and specificity of ONSD measurements to detect elevated ICP (>15 cm H2O).MethodsThis prospective study was conducted at the intensive care unit/high dependency units/wards of Aga Khan University Hospital. Patients with external ventricular drain (EVD) for intracranial hypertension were enrolled. Ocular ultrasound was performed with a 7.5 MHz linear probe. For each subject, three measurements on each eye were performed and the mean of the six measurements was determined. EVD was temporarily occluded and the ICP was recorded every minute for five minutes. A receiver operative characteristics (ROC) curve was constructed to determine the optimal ONSD cutoff to detect ICP above 15 cm H2O.ResultsA total of 35 adult patients were included in this study. The ONSD was linearly correlated with ICP in both right and left eyes (r = 0.662, p = 0.0005 and r = 0.449; p < 0.002) respectively. Pearson correlation of ONSD between two eyes (right and left) was 0.749; p = 0.0005 and 0.726; p = 0.005 at day 1 and day 2, respectively. ROC curve was created and observed that AUC of right and left eyes was 0.815 (95% CI: 0.61 to 0.99) and 0.69 (95% CI: 0.37 to 0.99).ConclusionAccording to this study, ventriculostomy measurements of ICP are directly correlated with ultrasound ONSD measurements. Hence, we conclude that ONSD measured by ocular ultrasound is a simple yet effective method to detect raised ICP.

Clinical Application of Intracranial Pressure Monitoring Based on Flash Visual Evoked Potential in Treatment of Patients with Hypertensive Intracerebral Hemorrhage

“…Similar to our research, ultrasonographic optic nerve sheath diameter (ONSD) is another noninvasive ICP monitoring technology through detecting optic nerve. Though it is a simple bedside ocular ultrasound used in detecting the elevated ICP, the ONSD is moderately correlated with ICP in both right and left eyes respectively and Pearson correlation of ONSD between two eyes (right and left) was 0.749 and 0.726 23 . The optimal ONSD cut-off for the identi cation of ICP has controversial, it uctuates from 0.48-0.5cm 24,25 .…”

Review: Optikussonografie – ein update 2020

“…Dieser Zeitverzug kontrastiert zu den teils sehr raschen ONSD-Rückbildungen in exakter Entsprechung zum gemessenen ICP, z. B. nach geplanter Öffnung einer "geblockten" externen Ventrikeldrainage [34] oder nach Dekompressionsoperation [28]. Solche Verlaufsuntersuchungen sind eine nützliche Applikation zur Beurteilung der Indikation von permanenten Shunt-Anlagen (Abb.…”

Accuracy of Intracranial Pressure Monitoring—Single Centre Observational Study and Literature Review

“…While they cannot drain CSF, they are easier to implant and carry a lower risk of infection than EVDs [ 1 ]. It is worth noting that because of the inherent risks and costs associated with invasive ICP monitoring, there have been many attempts to replicate it non-invasively using methods such as transcranial doppler ultrasound (including machine learning) or correlation with tympanic membrane displacement, (amongst others) [ 2 , 3 , 4 ]. While there have been advancements in this subject, it is a different challenge and beyond the scope of this review.…”