Endobronchial ultrasound-guided procedures performed under conscious sedation are increasingly used for the diagnosis and staging of mediastinal and pulmonary diseases. These procedures are often prolonged and are associated with a significant risk of hypoxemia due to sedation-related respiratory depression, partial airway obstruction by the bronchoscope, and underlying respiratory comorbidities. Maintenance of adequate oxygenation during EBUS under conscious sedation is therefore a critical component of procedural safety.

Conventional oxygen therapy is commonly employed during EBUS; however, it may be inadequate to prevent desaturation, particularly during periods of apnea or hypoventilation. High-flow nasal oxygen therapy has emerged as an alternative oxygen delivery strategy, offering higher flow rates, more stable inspired oxygen concentrations, and a potential reduction in hypoxemic episodes. Despite its increasing use, there is limited comparative evidence regarding the optimal oxygen delivery method, flow rate, and oxygen concentration during EBUS procedures performed under conscious sedation.

The purpose of this study is to compare different oxygen delivery strategies, including conventional oxygen therapy and various high-flow nasal oxygen modalities, during EBUS under conscious sedation, with respect to their ability to maintain adequate oxygenation and reduce peri-procedural hypoxemic events