Optic Nerve Sheath Diameter Estimation to Detect Increased Intracranial Pressure in Traumatic Brain Injury patients...

To evaluate the diagnostic accuracy of optic nerve sheath diameter (ONSD) measured by ultrasound as a non-invasive marker for detecting elevated intracranial pressure (ICP) in patients with traumatic brain injury (TBI), based on clinical and radiological findings.

This diagnostic accuracy study included 180 adult patients with isolated TBI admitted to a Level I Trauma Centre in Eastern India. ONSD was measured bilaterally using a 7.5 MHz linear ultrasound probe, 3 mm posterior to the globe. Clinical and radiological parameters were recorded, and increased ICP was determined based on a predefined clinical signs and computed tomography findings. Statistical analysis included logistic regression and receiver operating characteristic (ROC) curve analysis using Jamovi software.

The mean ONSD was significantly higher in patients with increased ICP (5.36±0.56 mm) compared to those without (4.13±0.34 mm, p<0.001). ROC analysis showed excellent diagnostic performance (area under the curve: 0.942), with sensitivity and specificity of 93.2% and 81.8%, respectively, at a cut-off value of 5.0 mm. The positive predictive value was 74.0%, and the negative predictive value was 99.0%. Increased ONSD was associated with TBI severity and poor Glasgow Outcome Scale scores at 3 months.

Ultrasound-measured ONSD is a sensitive, non-invasive bedside tool for detecting increased ICP in TBI patients, particularly useful in resource-limited settings.