In all patients, standard monitors and state and response entropy (SE and RE, respectively, GE Healthcare, Helsinki, Finland) based-depth of anesthesia will be applied. The radial artery will be catheterized. Anesthetic technique will be standardized in all studied patients. After preoxygenation, general anesthesia will be induced with propofol 1.5-3 mg kg-1 and target-controlled infusion (TCI) of remifentanil at an effect-site concentration (Ce) of 4 ng mL-1, to achieve the SE values below 50 and the difference between RE and SE below 10. Rocuronium (0.5 mg kg-1) will be given to facilitate the endobronchial intubation with a left-double lumen endobronchial tube and the correct position of its tip will be confirmed with a fiberoptic bronchoscope.