Optic Nerve Sheath Diameter Detects Intracranial Hypertension in Acute Malignant Middle Cerebral Artery Infarction

OBJECTIVEIntracranial hypertension and impaired cerebral autoregulation are common causes of secondary injuries in patients with traumatic brain injury (TBI). The primary outcome of this study was to assess whether a noninvasive method to estimate intracranial pressure (ICP) based on the ultrasonography of the optic nerve sheath diameter (ONSD) measured at the time of neurocritical care unit (NCCU) admission is correlated with the mean ICP during NCCU stay. Secondary outcomes were to assess whether ONSD is correlated with the dose of ICP > 20 mm Hg and impaired autoregulation during NCCU stay and with instantaneous ICP and whether ONSD is associated with NCCU mortality.METHODSThis prospective observational monocentric study included adults with severe TBI. ONSD was measured at NCCU admission, immediately after invasive ICP insertion. ONSD-predicted noninvasive ICP (nICPONSD) was calculated according the formula: nICPONSD= 5 × ONSD − 14 (nICPONSDin mm Hg, ONSD in mm). Autoregulation was measured using the pressure reactivity index (PRx).RESULTSIn total, 100 patients were included in this study. ONSD was significantly correlated with mean ICP (r = 0.46, p < 0.0001), with mean PRx (r = 0.21, p = 0.04), and with the dose of ICP > 20 mm Hg during NCCU stay (r = 0.49, p < 0.0001). Admission nICPONSDwas shown to be significantly correlated with instantaneous ICP (r = 0.85, p < 0.001). ONSD at admission was significantly correlated with NCCU mortality (p = 0.02).CONCLUSIONSONSD measured at NCCU admission can give important information about patients at risk of developing intracranial hypertension and impaired autoregulation. ONSD examination could be useful to screen patients at admission to determine who would benefit from further invasive ICP monitoring.

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MRI of the optic nerve sheath and globe in cats with and without presumed intracranial hypertension

Journal of Feline Medicine and Surgery ◽

10.1177/1098612x20976106 ◽

2020 ◽

pp. 1098612X2097610

Author(s):

Joanna Lodzinska ◽

Elizabeth Munro ◽

Darren J Shaw ◽

Anna Suñol

Keyword(s):

Optic Nerve ◽

Intracranial Hypertension ◽

Correlation Coefficient ◽

Pearson Correlation ◽

Optic Nerve Sheath Diameter ◽

Optic Nerve Sheath ◽

Transverse Diameter ◽

Mri Findings ◽

Good Reliability ◽

Nerve Sheath

Objectives The study aimed to: (1) test MRI repeatability of measurements of optic nerve sheath diameter (ONSD), optic nerve diameter (OND) and eye globe transverse diameter (ETD); (2) investigate the associations between the OND, ONSD and ETD; (3) assess whether these measurements are affected by age or body weight; and (4) test the association between ONSD, OND, ETD and ONSD: ETD ratio with presumed intracranial pressure (ICP) status. Methods This was a retrospective and blinded study where patients were allocated to presumed normal or intracranial hypertension groups based on MRI findings. The ONSD and ETD were measured and recorded. Interclass correlation coefficient (ICC) was calculated to investigate interobserver agreement. Data were analysed using the Pearson correlation coefficient, two-sample t-test and general linear model ANOVA. Results: Seventy-seven cats were included, 62 with presumed normal ICP and 15 with presumed intracranial hypertension. The ICC showed moderate-to-good reliability for all measurements. Positive correlations were identified for: (1) ETD and weight; (2) ONSD and age; (3) OND and age; (4) ONSD and ETD; (5) ONSD: ETD ratio and presumed ICP status; and (6) ONSD and presumed ICP status. No difference was detected between the presumed normal and intracranial hypertension groups and ONSD, as well as ONSD: ETD ratio and presumed ICP status when patient age was considered. Conclusions and relevance The measurement of the ONSD and the ONSD: ETD ratio on T2-weighted MRI might not be reliable as non-invasive tests for diagnosing intracranial hypertension in cats.

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