Patients undergoing general anesthesia with intubation received @ mg of @ % lidocaine ( lidocaine group ; n = @ ) , @ g/kg of dexmedetomidine ( low-dose group ; n = @ ) , @ g/kg of dexmedetomidine ( subclinical dose group ; n = @ ) , @ g/kg of dexmedetomidine ( clinical dose group , n = @ ) , or normal saline ( saline group ; n = @ ) before anesthetic induction .