Relationship of the optic nerve sheath diameter and repeated invasive intracranial pressure measures in traumatic brain injury patients; a diagnostic accuracy study

The purpose of this study was to quantitatively evaluate if the use of the optic nerve sheath diameter (ONSD) can be a suitable noninvasive surrogate approach for repeated invasive intracranial pressure (ICP) measures. 

The study used a sample of 22 adult patients with traumatic brain injury (TBI) from an in intensive care unit (ICU). ICP levels were measured using the gold standard and recorded in cmH20. ONSD was measured using ultrasonography with 5.6-5.7 MHz linear probe and recorded in millimeters. The data analysis was done using STATA software version 15. 

The results showed a strong positive correlation between ICP and ONSD (r = 0.743, p = 0.001). The accuracy of the sonographic ONSD declined over time, starting from a high of 90.9% at the baseline and declining to a low of merely 20.0% after 48 hours. 

These findings indicate that the ONSD approach could be very useful alternative and noninvasive method for monitoring ICP.