Pre - operative anxiety and emergence agitation are common issues among pediatric patients, which have various influences on the recovery progress and prognosis of children. Nasal administration of dexmedetomidine is a convenient and non - invasive sedation technique for children. This technique can reduce the incidences of pre - operative anxiety and emergence agitation. However, there are few studies on the effect of dexmedetomidine on intraoperative electroencephalographic activities.

In view of this, the investigators elaborately designed a prospective, multi - center, large - sample - sized, double - blind, randomized - controlled clinical trial. This trial aims to provide a basis for drug selection in pediatric anesthesia, ensuring the safety and comfort of pediatric anesthesia.

The investigators plan to select 627 participants who will undergo minor surgeries under general anesthesia. Thirty minutes before the surgery, dexmedetomidine or normal saline will be administered nasally to these participants. Before the surgery, the anxiety degree and sedation score of the participants will be assessed; during the surgery, the cooperation degree of patients during anesthesia induction will be evaluated and electroencephalographic monitoring will be carried out; after the surgery, the incidence of emergence agitation, the recovery time and the analgesic score of the participants will be assessed. Throughout the whole process, the occurrence of adverse reactions of participants will be fully monitored, and the adverse reactions will be timely recorded and treated.

Inclusion Criteria:

• 2≤ age ≤6 years old, gender is not limited;

  • ASA anesthesia grade I ~ II; ③ For children who intend to undergo minor surgery under general anesthesia (including but not limited to minor surgery such as ENT surgery and hernia surgery), the operation duration is expected to be no more than 2 hours; ④ Family members agree to participate in the study and voluntarily sign informed consent;

Exclusion Criteria:

• Respiratory tract infection occurs within 4 weeks before surgery;

  • Potential or other contraindications to general anesthesia;

    • There are nasal diseases, nasal bleeding, sinusitis, nasal polyps and other conditions that affect nasal absorption; ④ Heart, liver, kidney and other vital organ dysfunction or blood system diseases;

      • Allergy or intolerance to dexmedetomidine or other α2-adrenergic receptor agonists;

        • Patients with mental illness or neurological diseases;

          • Unable to complete the test, the child's guardian refused to participate; ⑧ Have participated in other clinical trials or need to participate in other clinical trials during the study period; ⑨ Other reasons that the researchers consider inappropriate to participate in this study.