Triple-cuffed double lumen endotracheal tube (TC-DLT, ANKOR tube. Insung corp., Korea) which was developed to isolate lung without endotracheal bronchoscope guidance has additional carinal cuff placed between bronchial tube cuff and tracheal tube cuff. This device has been successfully used to isolate lung more simply in specific settings when there is too much excretion to visualize endotracheal structure or for a health provider who is not good at use of traditional double-lumen tube. Although TC-DLT is designed to enable lung separation effectively in situations that confirmation of tube position using bronchoscopy is difficult or not available, but no studies have been conducted on whether effective lung isolation using TC-DLT is possible after change in the relative position of the bronchial tree by postural change. This plan was prepared for research on this.

After enter into operating room, induction of anesthesia is performed through standard general anesthesia procedure before endotracheal intubation. Endotracheal intubation is performed using TC-DLT and inflate carinal cuff with 5 ~ 15ml of air. Then, push it into trachea until resistance is felt. When carinal cuff is placed at carina, deflate carinal cuff and isolate independent lung followed by confirmation of bronchial cuff position using fiberoptic bronchoscopy.

Record the location of the bronchial balloon in one of the following conditions

1. at proper position(proximal upper end of bronchial balloon is between 5mm from carinal opening) :
2. proximal end of bronchial balloon is placed more of 5mm distally from carinal opening
3. proximal end of bronchial balloon is placed more of 5mm proximally from carinal opening

Then, change patient position to left lateral decubitus (LLD) position and check the position of bronchial balloon using fiberoptic bronchoscopy as previously done.

1. at proper position(proximal upper end of bronchial balloon is between 5mm from carinal opening) :
2. proximal end of bronchial balloon is placed more of 5mm distally from carinal opening
3. proximal end of bronchial balloon is placed more of 5mm proximally from carinal opening

After check whether there is something to considerate, end this case.

Inclusion Criteria:

• Adults who is including in ASA class I or II
• Patients scheduled for right lung surgery under right lung isolation
• Patients who don't have any anatomical variations in pulmonary system
• Patients who have never gotten a lung surgery

Exclusion Criteria:

• Pregnancy
• Patients who are predicted difficult intubation
• Patients who is under upper airway infection
• Patients who have coagulopathy
• Emergency surgery
• In addition, patients considered inappropriate to participate in this study

This study is multi center observational study and we will not share any patients data with other center

This study don't require any types of masking.