High-flow Nasal Cannula Versus Conventional Oxygen During Awake Tracheal Intubation With Difficult Airways

Study Background Airway management is one of the most fundamental and critical technical procedures in anesthesiology, critical care, and emergency medicine. Difficult airway management remains a major challenge in these fields, particularly when a "cannot intubate, cannot ventilate" scenario occurs during the induction of general anesthesia. Such events can rapidly lead to hypoxemia, resulting in brain injury or even death, and have become a significant source of anesthesia-related severe complications and medical disputes. Awake tracheal intubation (ATI) is considered the gold standard for airway management in patients with anticipated difficult airways, as it preserves spontaneous breathing and thereby reduces the risk of catastrophic airway failure during anesthesia induction. However, despite routine supplemental oxygen administration, hypoxemia remains one of the most common and potentially serious complications during ATI. When low-flow oxygen therapy (\

Inclusion Criteria: * Presence of an anticipated difficult airway; * Planned awake tracheal intubation; * Age ≥ 18 years; * Willingness to participate in the study and provision of written informed consent. Exclusion Criteria: * Contraindications to HFNC use, such as severe nasal obstruction or deformity, recent (within 3 months) nasal or skull base surgery, skull base fracture, or active epistaxis; * Hemodynamic instability, defined as a mean arterial pressure (MAP) \< 65 mmHg or the need for vasoactive medications to maintain blood pressure; * Pregnancy; * Current participation in another interventional clinical trial.