Efficacy of optic nerve sheath diameter by ultrasound as a non-invasive method to determine elevated intracranial pressure in Indian population

Abstract

Introduction: It is important to assess use of Optic Nerve sheath Diameter (ONSD) measurement by point of care ultrasonography (POCUS) as a non-invasive method for detecting elevated Intracranial Pressure (ICP) and to compare with Brain Computed Tomography (CT) findings of Elevated ICP in Indian population Methods: This study was a Prospective Observational Study done in emergency Department of a tertiary care hospital in western India .Adult patients within 18-60 years age group, with Head trauma presenting with headache, vomiting, convulsions, loss of consciousness, and altered sensorium were included in the study.Non-trauma patients with focal neurological changes and history suggestive of possible spontaneous intracranial hemorrhage were also included. Data was recorded after stabilizing patients as per standard trauma and non-trauma protocol. Patients underwent a POCUS study to measure the ONSD. Based on clinical judgment and ONSD measurement above the expected cut-off range, medical management for Elevated ICP was started. A Plain Brain CT Scan was obtained. Definitive treatment was planned after confirming on CT scan. ONSD measurement more than 6mm was suggestive of Elevated ICP Results: 108 patients were studied. A normal range of ONSD found was 3.5mm – 5.4mm. 26 patients had CT results consistent with Elevated ICP. All cases of CT-determined Elevated ICP were correctly predicted by ONSD. The sensitivity and specificity of this study is 98.75 % and 92.86% respectively. Conclusion: POCUS has the advantages of cost, time effective, non-invasive and reproducibility. It can be used as an additional diagnostic tool.

Keywords

• optic nerve sheath diameter
• point of care ultrasound
• intracranial pressure