The hypothesis of this study is that continuously delivering binaural beats with a phase difference corresponding to the slow-delta frequency band during anesthesia in pediatric patients can clinically and significantly reduce the required dose of the commonly used inhalational anesthetic, sevoflurane. To test this hypothesis, the study will compare the average end-tidal concentration of sevoflurane between a group exposed to continuous binaural beats (approximately 1 Hz phase difference) during surgery and a control group not exposed to such auditory stimulation.

Inclusion Criteria:

1. Pediatric patients under 3 years of age undergoing superficial surgery lasting more than 1 hour under general anesthesia (e.g., nevus excision, polydactyly/syndactyly surgery, dermoid cyst excision, thyroglossal duct cyst excision, preauricular fistula excision, inguinal hernia repair, orchiopexy, other mass excisions, strabismus surgery, etc.).
2. American Society of Anesthesiologists (ASA) physical status classification I or II.

Exclusion Criteria:

• Neonates or premature infants
• Children with hearing impairment or currently using hearing aids
• Children with neurological disorders
• Children with respiratory diseases
• Children undergoing neurosurgery or cardiac surgery
• Other patients deemed inappropriate for inclusion in the clinical trial at the discretion of the investigator or study staff