High-flow Nasal Cannula for Pediatric Anesthetic Induction

In the intervention group, pre-oxygenation was provided using HFNO via Optiflow THRIVE™ (Fisher and Paykel Healthcare Limited, Auckland, New Zealand) until SpO2 on pulse oximetry was > 95% and for at least 3 min. A flow of 0.5 l/kg/min-1 was used until induction agents had been administered, and then increased to 2 l/kg/min-1. Nasal oxygenation was continued without ventilation of the lungs while waiting for neuromuscular blockade, and during placing, replacing or repositioning the airway. Anaesthetists were free to carry out bag-mask ventilation of the lungs if they considered this necessary to maintain safe oxygen saturations. After securing the airway, the patient was connected to a circle circuit primed with 100% oxygen and the FIO2 was continued at 100% for a period of at least five more minutes. Relevant times were recorded, including start of pre-oxygenation and start of induction of anaesthesia.

In the control group, pre-oxygenation was provided using 100% oxygen via a sealed facemask and a circle-absorber anaesthetic circuit primed with 100% oxygen by installing a ventilation bag to the mouthpiece filter and ventilating the circuit with 100% oxygen. Anaesthetists were free to carry out bag-mask ventilation of the lungs once induction medications had been administered.