This clinical trial aims to compare the effects of lidocaine, dexmedetomidine, esmolol, and magnesium on optic nerve sheath diameter and hemodynamic response to laryngoscopy.
The participants will be patients determined to need intubation and general anesthesia for any elective surgery. Each participant will receive either lidocaine, dexmedetomidine, esmolol, magnesium, or none before anesthesia induction, according to randomization. The investigator will measure the optic nerve sheath diameter by ultrasonography before and after intubation. Researchers will compare the difference between optic nerve sheath diameter, systolic blood pressure, and heart rate before and after laryngoscopy and search for the most stable group. The trial aims to determine a general anesthesia induction protocol for patients sensitive to intracranial pressure changes reflected as optic nerve sheath diameter for easy monitoring.
Patients aged 18 to 80 years who will receive endotracheal intubation for general anesthesia and have an American Society of Anesthesiologists (ASA) Physical Status classification of I to III.
Patients allergic to dexmedetomidine, esmolol, lidocaine, and magnesium; patients with uncontrolled hypertension or advanced heart failure with EF below 35%; patients with cardiac arrhythmia, especially Type 2 and 3 blocks, supraventricular arrhythmias. Patients with renal failure (GFR below 30) or severe liver failure; patients with known acute or previous intracranial pathology and known diagnosis of epilepsy, predefined difficult airway examination. Patients who required more than one attempt at intubation or total laryngoscopy took more than 20 seconds.