One-lung ventilation can be provided by an endobronchial blocker. The Uniblocker® (Fuji Systems Corporation, Tokyo, Japan) was relatively recently introduced into clinical practice. We will try to devise a blind method to locate the Uniblocker® without the aid of fiberoptic bronchoscopy.

The use of a fiberoptic bronchoscopy (FOB) appears to be fundamental to adjusting position of the bronchial blocker in the targeted mainstem bronchus. However, there can be occasions when a FOB is unavailable or inapplicable. Therefore, we will try to devise a blind method to locate the blocker without the aid of FOB in patients undergoing thoracic surgery.

After intubation of endotracheal tube (ETT), the Uniblocker® is inserted into the ETT and is advanced until the blocker balloon comes out of the ETT tip. At this time, the blocker balloon is inflated with air and the peak inspiratory pressure (PIP) will abruptly increase. And then, the blocker is rotated to the thoracotomy side and advanced to the carina step by step at 0.5 cm intervals. When the PIP drops abruptly, the blocker cuff is deflated completely and advanced to 3 cm further. The blocker cuff is inflated again. Using a FOB, the position of the blocker is recorded and we will evaluate the success rate of proper blocker position.

Inclusion Criteria:

• patients undergoing thoracic surgery who need one lung ventilation

Exclusion Criteria:

• patients who have a lesion in trachea or mainstem bronchi
• severe tracheal deviation
• patients who do not agree to informed consent

patients undergoing thoracic surgery