ONSD and Neurotoxicity in Liver Transplant

"Patients were placed in the supine position with their eyes closed, and a thick gel layer was applied to the closed upper eyelid. The 7.5-MHz linear probe was placed on the gel without excessive pressure and adjusted to the proper angle for displaying the entry of the optic nerve into the globe. The intensity of the ultrasound was adjusted to display optimal contrast between the retrobulbar echogenic fat tissue and the vertical hypoechoic band. An ultrasound beam was focused on the retrobulbar area using the lowest possible acoustic power that could measure ONSD. The ONSD was measured 3 mm behind the optic disc. Measurements were performed in the transverse and sagittal planes of both eyes, and the final ONSD value was calculated by average 4 measured values.~We measured the ONSD at 4 timings: (T1) Post induction and before surgical incision, (T2) Portal vein clamping, (T3) 5 minutes after reperfusion, and (T4) 30 min after reperfusion."