Evaluation on the Proper Size of the Nasotracheal Tube and Depth in Nasotracheal Intubation: a Preliminary Study

The nasotracheal intubation is preferred for oral surgery; it provides an easier view of the surgical field. However, nasotracheal tubes are produced by foreign countries. Tubes are often not fitted in anatomy of Korean people because of small nostril. When the size of the tube is chosen by nostril size, the length of nasotracheal tube is not appropriate to the glottis. The aim of this study is to evaluate on the proper size of the nasotracheal tube and depth in nasotracheal intubation in Korean. Forty patients (20 males and 20 females) who are scheduled for nasal intubation for general anesthesia will be enrolled. The primary outcome is the proportion of patients who are in inappropriate insertion of nasotracheal tube; the proximal end of tube's cuff is less than 2 cm below vocal cord. The size of nostril, length from the nare to the carina and vocal cord are measured.

Inclusion Criteria:

• Patients who are scheduled for nasotracheal intubation for general anesthesia

Exclusion Criteria:

• age < 20 years and age > 70 years
• ASA(American Society of Anesthesiologist) class III or more
• pregnancy
• emergency surgery
• nasal airway disease
• expected difficult intubation (difficult intubation history, Modified Mallampati score 4, mouth opening <2cm, facial anomaly)
• unstable teeth