One-lung ventilation (OLV) is used for thoracic surgical procedures to facilitate surgical exposure. Lung isolation is performed using a double-lumen endotracheal tube (DLT) and optimal position is achieved with the use of fiberoptic bronchoscopy. The most common technique used to place a left-sided DLT is the blind method technique, which consists of direct laryngoscopy and rotation of the DLT into the trachea with the aim to intubate the entrance of the left main bronchus. The DLT will be rotated counterclockwise blindly after the tip of the DLT passes the vocal cords under direct laryngoscopy. However, in some occasions, the tip of the DLT migrates into the right bronchus because the alignment between the trachea and right bronchus is more vertical. The identification of the misplacement can be challenging, which could lead to the failure of lung isolation. In order to avoid the unsuccessful lung isolation, Investigators are interested in identifying the factors that potentially influence the incorrect tube DLT placement diverting into the opposite bronchus.

Recently, multi-detector 3-dimensional computed tomography (MDCT) scan of the chest is becoming a routine study for patients requiring thoracic surgical procedures. On the day of thoracic surgery, the participant will be intubated with a left-sided DLT and investigators will confirm the correct insertion of the left-sided DLT at first pass under direct laryngoscopy. This information will be recorded and saved. After the study is completed, investigators will review the MDCT of the chest to review any abnormal findings and correlate it with the success of the insertion of the left-sided DLT into the left bronchus. Investigators will conduct a pilot study to determine the most influential anatomical change that leads to the DLT misplacement at the first pass based upon the changes of the tracheal-bronchial anatomy on MDCT.

Inclusion Criteria:

• At least 18 years of age
• Adult patient undergoing scheduled thoracic surgery which requires left side double lumen tube placement

Exclusion Criteria:

• More than 90 years of age
• Patients with emergency surgery
• Prisoners
• Patients who cannot provide their own consent
• Patient refusal
• Non-English speaking patients

Adult patient undergoing scheduled thoracic surgery at University of Iowa Hospital

All of the individual participant data (IPD) collected during the trial, after de-identification will be shared with researchers who provide a methodologically sound proposal, to achieve aims in the approved proposal. IPD will be available for sharing immediately after publication and ending 5 years following article publication.

Individual participant data will be available for sharing immediately after publication and ending 5 years following article publication.

Individual participant data will be accessible to researchers who provide a methodologically sound proposal, to achieve aims in the approved proposal