Role of HFNC During FOB in Patients With Respiratory Failure

Inclusion Criteria: Participants will be eligible for inclusion if they meet all of the following criteria: 1. Adult patients undergoing clinically indicated fiber-optic bronchoscopy. 2. Patients with respiratory failure requiring supplemental oxygen or respiratory support. 3. Patients who provide written informed consent to participate in the study. Exclusion Criteria: * Participants will be excluded if they meet any of the following criteria: 1. Patients requiring immediate endotracheal intubation or invasive mechanical ventilation before bronchoscopy. 2. Patients with severe or refractory hypoxemia despite maximal non-invasive oxygen/respiratory support before the procedure. 3. Hemodynamic instability that precludes safe fiber-optic bronchoscopy. 4. Patients with contraindications to fiber-optic bronchoscopy or to the planned bronchoscopy procedure. 5. Patients who refuse or withdraw informed consent. 6. Patients in whom HFNC cannot be safely applied or tolerated.