Supplementary Material for: High flow oxygen does not improve oxygenation during rigid medical thoracoscopy

Introduction: The sedation required for rigid medical thoracoscopy may be associated with hypoventilation and intermittent hypoxaemia. High flow oxygen administration has been shown to decrease hypoxaemia during sedation for flexible bronchoscopy, a procedure using similar sedation protocols to medical thoracoscopy. Methods: Investigator initiated randomised controlled trial to compare conventional oxygen (starting at 4 L/min) to high flow nasal oxygen (starting rate 60 L/min and fraction of oxygen 0.6) during sedation for medical thoracoscopy. The mean nadir SpO2 during the procedure was the primary endpoint. Results: Between February 2022 and June 2023, 36 patients were randomised to either conventional oxygen (n=20) or high flow oxygen (n=16). The majority of participants (20/36, 55.6%) were male, and the mean age was 75.4 ± 10.4 years. The nadir SpO2 was 88.3% using high flow as compared to 85.0% for conventional oxygen (p=0.20). The average SpO2 (96.3% vs 96.2%, p=0.81) was similar between groups. There was a tendency towards a higher peak PtcCO2 in the conventional oxygen group (49.6 mmHg vs 55.5 mmHg, p=0.13). Conclusion: Oxygen supplementation using nasal high flow provides similar oxygen saturation to conventional nasal oxygen during sedation for rigid medical thoracoscopy.