This trial is a practical, multicenter, prospective, parallel grouping, randomized controlled,two-arm study. This study will be conducted in three centers including the First Hospital of China Medical University, Seoul National University Hospital and the University Clinical Center of Serbia. The investigators aim to investigate the effect of different occlusion angles of disposable tracheal blocker on right one-lung ventilation
Age ranged from 18 to 65 years old;
American Society of Anesthesiologists (ASA) grade I-III;
No history of drug allergy or abnormal anesthesia;
Patients undergoing right thoracoscopic surgery;
Patients with a history of acute lung injury or ARDS within 3 months;
Cardiac function class IV (New York Heart Association classification);
Chronic renal failure (renal cell filtration rate <30ml min-11.73m-2), severe liver disease;
Patients with blurred consciousness and cognitive dysfunction;