High Flow Nasal Cannula for Safe Apnea

Inclusion Criteria: * Children under 11 years old undergoing general anesthesia with American Society of Anesthesiologists Physical Status 1 or 2. Exclusion Criteria: * Refusal of enrollment from one or more legal guardians of the patient * Plan of usage of supraglottic airway device as airway maintenance device * Presence of upper respiratory tract infection of lung disease * Premature infants younger than postconceptual age of 40 weeks * Anticipation of difficult bag-mask ventilation due to facial anomaly or micrognathia * Other conditions that are considered inappropriate for the study