Change in the study plan

This study aims to evaluate the effect of high-flow nasal oxygenation on safe apnea time for children undergoing general anesthesia, with their mouth open.

Oxygenation via high-flow nasal cannula is gaining popularity in various clinical settings. It is known to increase apnea time for apneic patients including children. However, high-flow nasal cannula is known to be ineffective when the patient's mouth is kept open.

When trying to intubate the patient during induction of anesthesia, the patient should be apneic with administration of neuromuscular blocking agent, and the mouth should be open for introduction of laryngoscope.

We designed a prospective randomized controlled study to evaluate the effect of high-flow nasal oxygenation in the aforementioned setting for trying to intubate the patient.

Inclusion Criteria:

• Children younger than 11 years old scheduled to undergo surgery under general anesthesia, with American Society of Anesthesiologists Physical Status 1 or 2.

Exclusion Criteria:

• Refusal to enrollment from one or more of legal guardians of the patient
• Children who are planned to use supraglottic airway device
• Children with upper respiratory tract infection or pulmonary interstitial disease
• Preterm babies under 40 weeks of postconceptual age
• Children who are expected to have difficult airway for bag-mask ventilation