Flexible Bronchoscopy Insufflated and High-Flow Nasal Oxygen Pilot Trial in Children

Infants and children with an abnormality in their airway and lungs often require procedures to further investigate their lungs and improve their breathing. During the anaesthesia for this procedure, the anaesthetist delivers oxygen and monitors the adequacy of the child’s breathing. In this situation both the proceduralist and the anaesthetist share the child’s airway for delivery of oxygen and for placement of a small telescope to directly view the anatomy within the airway and lungs. It is impractical for the anaesthetist to place a breathing tube into the airway for delivery of oxygen as this obstructs the view. It is not uncommon for the oxygen levels in the blood to fall (hypoxaemia) during these procedures. The procedure may need to be interrupted to correct this which can potentially compromise the safety of the child, prolong the procedure, increase exposure to anaesthetic agents and affect the success of the procedure. At Queensland Children’s Hospital, we reviewed the anaesthetic care of children undergoing flexible bronchoscopy procedures and found that 28% of children experienced low oxygen levels one or more times during the procedure. The method which the anaesthetist chooses to give the oxygen to the child may help to prevent the occurrence of low oxygen levels. Traditionally anaesthetists have delivered oxygen via face mask or airway device which is placed inside the mouth above the voice box part of the airway at flow rates of up to 6 litres per minute. Our research team have recently investigated a new mode of oxygen delivery called Nasal High. Flow. In Nasal High Flow, warm and humidified oxygen is delivered to the airway via nasal cannulae, at a rate determined by the child’s weight. For example, Nasal High Flow can be delivered at rates of 2L/kg/min. Therefore, a 10kg infant would receive 20 litres per minute. Matching the flow delivered to the patient’s breathing allows the anaesthetist to deliver oxygen to the child at the required concentration. Our recent studies have demonstrated Nasal High Flow is an effective alternative technique for oxygen delivery that can be safely used in infants and children with abnormal airways. To date there have been no large-scale studies evaluating Nasal High Flow in comparison to other oxygenation techniques during flexible bronchoscopy in children. Therefore, we aim to compare the two techniques using a randomised controlled trial in infants and children during flexible bronchoscopy. If we can determine that Nasal High Flow reduces the risk of low oxygen levels, this has the potential to both improve both the safety and the success of these procedures for children.