Effect of Lidocaine Infusion Versus Dexmedemidine Infusion on the Neurocognitive Function of Elderly Patients Undergoing Endoscopic Retrograde Cholangiopancreatography(ERCP).

Inclusion Criteria: The study will include all patients aged 65 years or older of both sex with an ASA I -II - III (as controlled HTN, controlled DM), (MMSE\>24) who scheduled for elective ERCP under total intravenous general anesthesia. Exclusion Criteria :will involve patients lacking informed consents, with severe cardiovascular, respiratory, central nervous system, or kidney dysfunction, communication or assessment impairments, and suspected severe neurocognitive impairment (MMSE score \<24). patients with anticipated airway difficulties, alcohol or drug dependence, current sedative, antidepressant, or corticosteroid use, allergy to dexmedetomidine, lidocaine or other used anesthetics, baseline heart rate less than 50 beats per minute due to bradycardia, sick sinus syndrome, or second-degree or higher atrioventricular block without a pacemaker. \-