High-Flow Nasal Cannula for Preventing Hypoxia During Sedated Endoscopy in High-Risk Obstructive Sleep Apnea Patients

Inclusion Criteria:

* Age ≥18 years.
* STOP-Bang score ≥5.
* Scheduled for sedated gastrointestinal endoscopy (gastroscopy, colonoscopy, or combined gastroscopy + colonoscopy).
* The estimated duration of the procedure does not exceed 45 minutes.
* Patients have signed the informed consent form.

Exclusion Criteria:

* Coagulation disorders or bleeding tendency (e.g., oral/nasal bleeding risk, mucosal injury, space-occupying obstructions).
* Active upper respiratory tract infection (oral, nasal, or pharyngeal), or fever (core temperature \>37.5°C).
* Chronic obstructive pulmonary disease or other acute/chronic pulmonary diseases requiring long-term or intermittent oxygen therapy, or preoperative SpO₂ ≤ 92% on room air.
* Severe organ dysfunction, including: Cardiac insufficiency (\<4 METs), Severe renal insufficiency (requiring dialysis), Diagnosed severe hepatic insufficiency, Increased intracranial pressure, ASA physical status ≥ IV.
* Confirmed pregnancy or current breastfeeding.
* Known allergy to sedatives (e.g., propofol) or medical adhesives.
* Multiple traumatic injuries.
* Current participation in another clinical trial.
* Other conditions deemed unsuitable by the investigator