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

INTERVENTION: Intervention: High flow nasal oxygen insufflation Description: High‐Flow Nasal Oxygen Insufflation (HFNOI) is insufflation of heated (37 degrees Celsius) and humidified (100%) oxygen at weight‐related flow rates matching peak inspiratory flow thereby allowing a known inspired fraction of inspired oxygen. HFNOI will be delivered during the bronchoscopy via the Optiflow™ device at weight‐specific flow rates as per the table below delivering a FiO2 of 1.0. Weight HFNOI Flow rates 0‐12 kg 2L/kg/min 13‐15kg 30L/min 15‐30 kg 35L/min 30‐50 kg 40L/min >50 kg 50L/min Jaw thrust will be applied to ensure a patent airway until airway instrumentation begins. Anaesthesia will be maintained via a Total Intravenous Venous Anaesthesia (TIVA) using a combination of dexmedetomidine, propofol +/‐ an opioid (either remifentanil or alfentanil) at the discretion of the attending anaesthetist. Anaesthetists may wish to omit opioids in certain circumstances and this will be at the discretion of the anaesthetist e.g. neonates. Anaesthesia infusions will be adjusted to maintain both adequate depth of anaesthesia and spontaneous ventilation during the procedure. TIVA is used because inhalation agents can not be delivered when using HFNOI, TIVA is not the intervention of interest. The adherence to the intervention will be monitored by the research assistant present in the room collecting data and recorded on a case report form. CONDITION: Anaesthesiology ‐ Anaesthetics Hypoxemia during Flexible Bronchoscopy; ; Hypoxemia during Flexible Bronchoscopy Respiratory ‐ Other respiratory disorders / diseases Surgery ‐ Other surgery PRIMARY OUTCOME: Adherence to the protocol without deviation assessed by completion of case report form completed by the research assistant during the bronchoscopy [During the bronchoscopy for children enrolled ] The rate of participant recruitment assessed by completion of screening and enrollment log[Screening will occur daily by the research assistant until the recruitment target has been met.] SECONDARY OUTCOME: Significant adverse events requiring treatment will be graded using the CTCAE5. ; AEs for this study are defined as: ; *Hypoxaemia leading to cardiac massage ; *Cardiac arrest: Loss of spontaneous cardiac output ; *Mortality ; *OR any life‐threatening medical event or reaction which the clinician believes may be study‐related ; *Hypotension: requiring treatment with fluid and/or vasoconstrictors INCLUSION CRITERIA: * 0 (>37 weeks gestational age) – 16 years of age (15 years + 364 days) • Elective flexible bronchoscopy *Clinicians approval for inclusion ; *Bradycardia of <60/min or < 40 if older than 6 years [Continuous observation by the research assistant for the duration of the surgical procedure] The proportion of children experiencing a hypoxaemic event defined by a oxygen saturation < 90%, within 10% of baseline collected by pulse oximeter data captured during the bronchoscopy[Continuous pulse oximetry will be taken during the surgical procedure] The proportion of children requiring interruption of the procedure to rescue the oxygenation by positive pressure assisted ventilation assessed by observation and completion of case report form completed by the research assistant during the bronchoscopy [Continuous observation by the research assistant for the duration of the surgical procedure] The severity of the hypoxaemic event described by the area under the curve of time below SpO2 of 90% collected by pulse oximeter data captured during the bronchoscopy[Continuous pulse oximetry will be taken during the surgical procedure]