To determine which nostril is more suitable for nasotracheal intubation with video rigid stylet.

Head and neck surgeries usually require nasal intubation, which allows leeway for operative maneuvering in the mouth, pharynx, larynx, and neck. Previous studies have found that the right nostril is more appropriate for nasal intubation using direct laryngoscope or videolaryngoscope. It has been shown that the optical rigid stylet was also an appropriate tool for nasal intubation. However, nasal intubation with rigid optical stylet is technically different from that with laryngoscope. It is unknown whether the choice of nostril could affect the intubation using rigid optical stylet. The main aim is to determine which nostril is more suitable for nasal intubation with video rigid stylet.

Inclusion Criteria:

1. Age ≥ 18 years;
2. American Society of Anesthesiologists physical status I~II;
3. Scheduled to undergo elective oral and maxillofacial surgery requires nasal intubation;
4. The expected operation time < 3 hours;
5. Extubation in operation room and do not scheduled to preventive tracheotomy;
6. Patients who were able to breathe clearly and equally through both nostrils.

Exclusion Criteria:

1. Patients had history of difficult intubation or presented with an anticipated difficult airway;
2. Patients requiring nasogastric tube insertion;
3. Presence of contraindications of nasal intubation;
4. Due to surgical requirement, intubation must be completed through one nostril;
5. Presence of severe nasal obstruction,deformities of the nasal cavity, or other serious nasal diseases;
6. History of severe epistaxis or epistaxis within a month;
7. Previous history of nasal and/or laryngeal surgery;
8. Previous experience with nasal intubation;
9. History of schizophrenia, Parkinson's disease or profound dementia, or language barrier;
10. Participate in other clinical studies;
11. Refusal to sign informed consent.