The Effect of Suspension Laryngoscopy Application on Optic Nerve Sheath Diameter, an Indirect Indicator of Increased Intracranial Pressure

Optic nerve sheath diameter (ONSD) measurement will be performed by ultrasonography (USG) at 5 different times in patients undergoing suspension laryngoscopy. Participants will be monitored from the time of commencement of suspension laryngoscopy to the time of discharge from the post-anaesthesia care unit. Suspension laryngoscopy is expected to take at most 1 hour. ONSD measurements will be made by a trained anesthesiologist. An 8.0 megahertz linear USG probe applied with a thin layer of gel will be carefully placed on the closed upper eyelid. Avoiding excessive pressure, the probe will be adjusted to show the optic nerve entry into the eyeball in 2D mode. The image will be frozen after optimal contrast is achieved between the hypoechoic image of the optic nerve and the echogenicity of the retrobulbar adipose tissue. ONSD will be measured 3 mm behind the optic disc using the electronic caliper of the USG. The measurement will be made 4 times, 2 horizontal and 2 vertical, for a single eye, and the average of these 4 measurements will be considered as ONSD. Measurements will be repeated at 5 different times and from the same eye. The times to be measured; It will be defined as T0 (after induction of anesthesia), T1 (immediately after intubation), T2 (with the head in extension at the beginning of the suspension laryngoscopy), T3 (at the end of the suspension laryngoscopy), T4 (with the head in a neutral position 5 minutes after the suspension laryngoscopy is terminated). During these 5 times, along with ONSD measurements, patients' heart rate, noninvasive mean arterial pressure, end-tidal CO2 values, saturation values, peak inspiratory pressure values will also be recorded. All patients' ages, genders, ASA scores, Mallampati scores, body mass indexes (BMI) will be recorded. Suspension laryngoscopy times will also be recorded. It will also be recorded how long after the patients were awakened, they were compiled. For this, the Modified Aldrete Score will be used, and if this score is 9 and above, the patient will be considered compiled.