Introduction:

Traumatic brain injury is a cause of death and neurological sequelae in Mexico. The main cause of death for these group of patients is intracranial hypertension. There are invasive and non-invasive intracranial pressure monitoring techniques. Within the non-invasive techniques group, perhaps the most accessible one could be the bed-side measurement of the diameter of the optic nerve sheath. Our study pretends to find the most precise distance in millimeters to measure de optic nerve sheath compared to measurements performed by cranial computed tomography.

Material and methods:

A prospective, observational, transversal, analytical study was made with patients admitted in the Neurologic Intensive Care Unit from the Hospital General de Ecatepec Las Americas, whose met the inclusion criteria. The study was performed between November the 1st of 2018 and January the 31th of 2019. We compared the diameter of the optic nerve sheath measured by ultrasonography at 3, 6 and 9 mm distance from each eye-ball versus the sizes obtained by cranial tomography at the same distances.

Results:

No statistically significant difference was found by comparing ultrasonography acquired versus cranial tomography acquired optical nerve diameters, at none of the three mentioned distances (3, 6 and 9 mm) with a p value > 0.05 for all of them. The minor difference was found at 3 mm from the eye ball, but again, without statistical significance. Most of the studied patients were economically active men, and the most frequent injury found by cranial tomography was subarachnoid hemorrhage.

Conclusions:

There is no statistically significant difference between the tomography measurement of optical nerve at 3, 6 and 9 mm and the measure of the optic nerve sheath at the same distances, in severe traumatic brain injury patients. Nevertheless, at 3 mm distance from the eyeball the minor difference was found between both techniques, the same distance traditionally described in consulted bibliography.

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