Rhinoscope is useful to exam intranasal structure. This information could be utilized to select more suitable nose for nasotracheal intubation. Nastoracheal intubation using more patent nose could be associated with decrease of the development of epistaxis which is most common complication in nasotracheal intubation.

Anterior rhinoscopy using rhinoscope is a simple way to view the intranasal structure, which allows you to observe the nasal mucosa, the inferior nasal concha, and in some cases, the nasal concha. You can see the nasal septum, polyps, and intranasal malformations. In addition, even when there are no structural abnormalities in the nasal cavity, the wider nasal cavity can be intuitively identified. This information is expected to assist in the selection of nostrils. It has not yet been studied whether anesthesiologists select nasal cavity for nasotracheal intubation using prosthesis can affect the occurrence of epistaxis.

The purpose of this study is to determine whether the selection of a nostril for nasotracheal intubation by rhinoscope affects the incidence and severity of epistaxis.

Inclusion Criteria:

• ASA I or II undergoing surgery under nasotracheal intubation

Exclusion Criteria:

• expected difficult intubation based on history, physical examination, weight.
• bleeding tendency
• past history of nasal surgery
• symptom of difficulty of nasal respiration

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