Nasotracheal intubation(NTI) is commonly used in operations of the mouth, pharynx, larynx and also the neck. While these patients showed higher rates of difficult laryngoscopy. Therefore, duration of apnoea is prolonged and re-oxygenation is inevitable.Mask ventilation is the most fundamental technique in maintaining oxygenation, even when endotracheal intubation is failed. However, the most common complication of NTI is epistaxis, removing the nasotracheal tube could make mask ventilation extremely difficult.So the investigatorsbelieve the ideal approach is ventilation through original nasotracheal tube.Several techniques of supraglottic ventilations through endotracheal tubes have been reported.It remains uncertain whether supraglottic ventilation through inflated nasal RAE endotracheal tube has similar efficiency as mask ventilation after general anesthesia induction. Based on previous clinical experience, the investigators hypothesised that ventilations through inflated nasal RAE endotracheal tube and through facemask were comparable in terms of tidal volume and airway pressure in anesthetized, apnoeic adults.

Forty patients were randomly assigned (sealed envelope method) to face mask（Group A，n=20）or nasal ventilation(Group B，n=20), For A: face mask ventilation followed by nasal ventilation and for B:nasal ventilation followed by face mask ventilation.Measure the tidal volume and air leakage of face mask and nasal ventilation during pressure-controlled ventilation mode and volume-controlled mode, respectively.

Inclusion Criteria:

• Age between 18-55 years old
• ASA physical status I and II
• Requiring general anesthesia with nasal intubation

Exclusion Criteria:

• Respiratory disease，cardiovascular disease, cerebral vascular disease
• Anticipated Difficult Mask Ventilation(Age>55 years old, obesity,bearded,edentulous,a history of snoring)
• The need for emergency surgery
• Contraindications to nasal intubation
• Pregnancy
• Gastric-esophageal reflex or a full stomach