High Flow Nasal Oxygenation for General Thoracic Patients during Diagnostic Bronchoscopy. Comparison of conventional methods of respiratory support during bronchoscopy vs. High Flow Nasal Cannula.

INTERVENTION: Nasal high flow oxygen therapy has been widely investigated in many areas of in‐hospital patient care. It can deliver up to 60L/min of humidified air and oxygen. Documented mechanisms of action for high flow include dead space clearance and washout, splinting of the upper airway and maintaining pulmonary conductance and compliance. Participants undergoing diagnostic bronchoscopy will be deemed 'high' or 'low' risk by treating anaesthetist, as per standard practice at this institution. 'Low' risk participants will receive light sedation and local anaesthetic for their bronchoscopy. Participants in this group will be randomised to receive either High Flow nasal cannula oxygen therapy at 60L/min or standard practice low flow oxygen therapy via nasal cannula or bite block (decision on nasal cannula vs. bite block will be at the discretion of the treating physician) for the duration of their bronchoscopy procedure and in recovery. Observational 'High' risk participants will receive general anaesthesia and a dedicated airway (LMA). Standard oxygen therapy will be administered during recovery. Study period will be approximately two hours for procedure and recovery time. Time will vary depending on bronchoscopy findings. Continuous haemodynamics, pharyngeal pressures and electrical impedance tomography, specifically end expiratory lung volumes, will be monitored. Additionally, time in and out of recovery will be documented as well as patient/staff satisfaction survey recorded. CONDITION: Respiratory support for general thoracic patients undergoing Bronchoscopy PRIMARY OUTCOME: Change in end‐expiratory lung volume from patient's baseline using electrical impedance tomography. SECONDARY OUTCOME: Bronchoscopist and bronchoscopy staff satisfaction using a 7‐point analogue scale after the conclusion of the procedure. Change in CO2 from baseline using a transcutaneous carbon dioxide monitor. ; ; Change is SpO2/FiO2 ratio from baseline Economic Evaluation through the assessment of the cost of human and material resources. Lowest SpO2 during the procedure via transcutaneous oximetry monitoring. ; ; Patient dyspnoea and comfort via a 10‐point, visual analogue scale. ; ; INCLUSION CRITERIA: 1. Eighteen (18) years + 2. Routine bronchoscopy in general thoracic patients 3. Able to give informed consent