We aim to investigate the effects of premedication (intranasal or intravenous administration) of s-ketamin, dexmedetomidine, and combination for premedication in children undergoing ENT surgery.

Three hundred children aged between 2 and 12 years were randomly allocated to one of five groups: 0.3 μg/kg intravenous injection s-ketamin; 0.5 μg/kg intravenous injection s-ketamin; 2 μg/kg intranasal s-ketamin group; 1 μg/kg intranasal s-ketamin + 1 μg/kg intranasal dexmedetomidine group; 0.5 μg/kg intranasal s-ketamin + 2 μg/kg intranasal dexmedetomidine group.

The modified Yale Preoperative Anxiety Scale (m-YPAS) was used to assess preoperative anxiety at 1, 5, 10, 20, and 30min after premedication. A 4-point emotional state score was used to evaluate participators when they were separated from their parents and their response to intravenous cannulation or facemask application. Agitation scores (Pediatric Anesthesia Emergence Delirium [PAED] scale) and POV was assessed in the postanesthetic care unit (PACU). Times to endotracheal tube or laryngeal mask airway removal, discharge from the PACU, and patients' satisfaction degree were also assessed.

Inclusion Criteria:

• After obtaining the informed consent from their parents or proxies, the children aged 2 to 12 years, scheduled for elective ENT surgery, of American Society of Anesthesiologists (ASA) I or II were enrolled in this study.

Exclusion Criteria:

• Congenital heart diseases, congenital dysplasia, obstructive sleep apnea syndrome, upper respiratory tract infection, body mass index (BMI) ≥25, allergy to S-ketamin or dexmedetomidine, and severe liver or kidney disease.