SEALion: Study on Supplemental Oxygenation Via Nasal Cannula for Young Children During Intubation

Tracheal intubation in neonates can be technically challenging, even for experienced pediatric anesthesiologists, with a high first-attempt success rate crucial to ensure safety. Intubation, while life-saving for children with circulatory shock or respiratory failure, carries risks of severe desaturation that can lead to hypoxic encephalopathy, cardiac arrest, or death. Neonates, especially, are prone to hypoxemia due to high oxygen consumption, low functional residual capacity, small closing capacity, and increased risk of airway collapse, which is exacerbated under anesthesia and neuromuscular paralysis. Rapid desaturation occurs after cessation of ventilation, with neonates facing shorter apnea times before desaturation. Studies show that about two-thirds of neonates undergoing non-emergency nasotracheal intubation experience desaturation (SpO₂ \<80% for over 60 seconds), although low-flow oxygen supplementation (0.2 L/kg/min) can extend safe apnea time. This study aims to investigate apneic oxygenation with VL (using Miller or Macintosh blades size 0 or 1) in operating rooms or intensive care units. We hypothesize that supplemental oxygen and standardized VL use will improve first-pass success rates and reduce adverse events.

Eligible children will undergo preparation for intubation following the local Standard Operating Procedures (SOPs) of the pediatric anesthesia departments. Mandatory monitoring includes pulse oximetry (SpO2), heart rate (HR), and non-invasive blood pressure (NIBP). Anesthesia Induction: Where feasible, all children enrolled in this protocol will be pre-oxygenated for one minute prior to induction of anesthesia using a face mask with FiO2 1.0 and a flow rate of 6-10 L/min. Anesthesia induction for tracheal intubation will involve a combination of sedative or hypnotic drugs, opioids, and a non-depolarizing muscle relaxant. Required Medications (per protocol): Neuromuscular Blocking Agent (NMBA): One of the following-Rocuronium 0.5-1 mg/kg, Cis-Atracurium 0.2-0.5 mg/kg, Atracurium 0.5 mg/kg, Vecuronium 0.1 mg/kg, Mivacurium 0.2-0.3 mg/kg, or Succinylcholine 2 mg/kg. Hypnotic Agent: One or more of the following-Thiopentone 4-7 mg/kg, Ketamine 0.5-2 mg/kg, Propofol 1-4 mg/kg, Midazolam 0.5-1 mg/kg, or Sevoflurane up to 8%. Optional Medications: An opioid and/or anticholinergic may be administered at the anesthetist's discretion. Pre-Intubation Preparation: Following induction of anesthesia and administration of an NMBA, bag-mask ventilation with FiO2 1.0 (flow rate of 6-10 L/min) will be performed for 60 seconds until apnea occurs. To facilitate airway management, complete neuromuscular blockade will be confirmed using train-of-four (TOF) monitoring. Oxygen administration, laryngoscopy, and tracheal intubation will follow. Intubation Procedure: Oxygen administration during intubation is mandatory for all participants and will be randomized as follows: Apneic Oxygenation: Oxygen will be administered at 1 L/kg/min via a conventional nasal cannula. Laryngoscopy and tracheal intubation will proceed following apneic oxygenation. Standard Care: No apneic oxygenation will be administered. After induction, laryngoscopy and tracheal intubation will proceed without additional oxygen support. Tube Selection: For premature neonates under 1 kg, an uncuffed tube with an internal diameter (ID) of 2.5 will be used. For premature neonates and newborns between 1 kg and 3.0 kg, an uncuffed tube with ID 3.0 will be used. For babies over 3.0 kg up to 8 months, a cuffed tube with ID 3.0 or an uncuffed tube with ID 3.5 will be used. For infants aged 8 to 12 months, a cuffed tube with ID 3.5 or an uncuffed tube with ID 4.0 will be used. Oxygen delivery will follow the assigned randomization group, either via conventional nasal cannula (apneic oxygenation) or standard care. Laryngoscope Blade Selection: For children weighing less than 1 kg, a Miller or Macintosh blade, size No. 0, will be used. In cases of unexpected difficult intubation, the difficult airway algorithm will be applied. After an unsuccessful first intubation attempt with the assigned flow rate, clinical judgment will guide the intubating physician on whether to repeat the attempt with the same flow rate or to modify the flow rate, blade size, or type of laryngoscope. A maximum of four intubation attempts will be allowed, with the final attempt performed by the most experienced physician present. Additional tools, such as a stylet or bougie, may be used at any stage. If intubation remains unsuccessful, the difficult airway algorithm will be applied, and a supraglottic airway (SGA) device will be inserted.