STRIVE-Hi (SponTaneous Respiration under IntraVEnous anaesthesia with High flow oxygen) oxygenation for asleep flexible bronchoscopic intubation in patients requiring nasotracheal intubation - a feasibility study

Evaluation of STRIVE Hi oxygen delivery for performing and teaching asleep flexible bronchoscopic intubation. 1. Anaesthetic trainees are given brief teaching on asleep flexible bronchoscopic intubation and bronchoscope manipulation. (Talk through / hands on in theatre with flexible brochoscope set up and manipulation by study trainer) 2. After standard theatre checklists are completed, the patient is brought into the operating theatre. 3. An intravenous cannula is inserted and routine monitoring is applied as per standard guidelines. In addition, the ECG is used for respiratory rate monitoring using ECG derived thoracic impedance. 4. High flow nasal cannula (OptiflowTM, Fisher & Paykel, Auckland, NA) is placed on the patient’s forehead. 5. The patient is placed in a sitting or semi-recumbent position as tolerated. 6. Face mask preoxygenation with FiO2 100% at 6 l/min. 7. Intravenous midazolam 0.5-1.0 mg (at discretion of anaesthetist based on patient’s weight and frailty). 8. Intravenous analgesia: remifentanil infusion (50 mcg/ml) until the effect site concentration (Ce) 1.5 ng/ml (Minto model) is reached. 9. Intravenous anaesthesia: propofol 1% infusion started at Ce 1.5 mcg/ml (Schnider model). 10. Metaraminol (10 mg in 20 ml saline) infusion is commenced at 5-10 ml/hour at the discretion of the anaesthetist, and further titrated to maintain adequate blood pressure as patient in sitting or semi recumbent position. 11. Jaw thrust is gently applied throughout to open that patient’s airway, stimulate ventilation and assess depth of anaesthesia. 12. Propofol Ce is slowly increased by increments of 0.5 mcg/ml until a target of up to 4-6 mcg/ml is reached to tolerate subsequent laryngoscopy.(20) 13. The OptiflowTM nasal cannulae are lowered into the patient’s nostrils to provide warm, humidified oxygen at a flow rate of 60 l/min. Jaw thrust is maintained. 14. Nasal decongestant Otrivin 0.1% (xylometazoline) is administered into the nostril. 15. Asleep flexible bronchoscopic intubation is performed by the trainee anaesthetist with the Specialist supervising and teaching airway anatomy and bronchoscope manipulation. 16. Vocal fold spraying with lignocaine 2% 4 ml prior to railroading tracheal tube over the bronchoscope. 17. Measurements are recorded as per the case report form: patient’s physiological parameters every minute (pulse, blood pressure, SpO2, respiratory rate); bronchoscope instructions given by Specialist; induction and teaching timings; and complications and airway interventions. 18. After the asleep intubation is completed, machine ventilation is started (CPAP/PS with minimum respiratory rate 12 /min; pressure support 10 cmH20; and CPAP 5 cmH2O). End tidal carbon dioxide values from the first three full capnograph waveforms are recorded. (approximately 15 minutes from arrival in theatre to intubation confirmation) 19. Induction and teaching times are recorded. 20. Study is completed after successful asleep flexible bronchoscopic intubation and three full capnography waveforms are obtained. 21. Study to be terminated if: patient’s SpO2 <90% or duration 15 minutes. Defaults to subsequent patient management as per the anaesthetist’s standard of care. 22. Trainee feedback is obtained via an online feedback form. No assessing or monitoring of fidelity