The dexmedetomidine group ( Group D , n = @ ) received a continuous infusion of dexmedetomidine at a rate of @ g kg ( -@ ) hour ( -@ ) from the induction of anesthesia until the end of the ST position , while the control group ( Group C , n = @ ) received an equal volume of physiologic saline at the same rate under conventional general anesthesia with sevoflurane and remifentanil .