Postoperative Dexmedetomidine in Prevention of Postoperative Delirium

Exclusion Criteria

• •local allergy to anesthetics;
• •patients with a clear preoperative history of nervous system and mental system diseases or long-term use of sedatives or antidepressants;
• •history of alcoholism, drug abuse or drug dependence;
• •have a history of brain surgery or injury;
• •epilepsy and associated mental and cognitive dysfunction, long-term stress stimulation, or psychological disorders;
• •sick sinus syndrome, second-degree or greater atrioventricular block or other contraindications for use of α2 adrenergic agonist;
• •liver and kidney insufficiency.