Objective Pre-oxygenation in paediatric EmeRgent Airway management (OPERA): assessing the efficacy of pre-oxygenation techniques - A prospective cohort study.

This is a once-off intervention performed at the hospital face to face by a research clinician. No ongoing involvement or follow up is required. When the patient is ready, pre-experiment measurements will be taken & documented - these are SpO2, FeO2, ORi which are all non-invasive measurements of oxygen levels in the lungs and blood. The patient will then have oxygen applied using each of the techniques for a period of 3 minutes each. At the end of each period the FeO2, SpO2 and ORi will be re-recorded. After this monitoring of ORi will continue until it reaches 0. The time take to return to 0 will be documented. A further washout period of not less than 15 minutes will then be provided before the next technique is undertaken. The four preoxygenation techniques to be investigated are: • Non-rebreather mask with 15L/min of oxygen flow • Standard nasal prongs with 15L/min of oxygen flow • Nasal high flow cannuale with 2L/kg/min of oxygen flow and FiO2 100% • Anaesthetic t-piece with mask (applied with adequate seal) with age appropriate flow and FiO2 100% Each device will be applied to the participant when they are seated or lying down after being appropriately sized using sizing guidelines and clinical assessment to ensure a good seal is achieved. A clinician will remain with each participant to ensure adherence for the duration It is expected the total duration will be 1-1.5 hours