A randomized controlled trial on the positioning effect of new wall-less and conventional right-sided double-lumen bronchial catheters in patients undergoing left thoracoscopic surgery

INTERVENTION: E group:Use the new type of double‐chamber bronchial catheter without a tube wall;NC group:Use the Covidien right double‐lumen bronchial tube; CONDITION: Difficulty in positioning after right‐sided double‐lumen tube intubation with a narrow safety range PRIMARY OUTCOME: The success rate of the first exposure after intubation; SECONDARY OUTCOME: Intubation time;The number of cases requiring intervention due to inadequate one‐lung ventilation;Repositioning time after turning;Arterial blood gas analysis at 30 min after one‐lung ventilation: PaO2, PaCO2;Increase rate of peak airway pressure;Incidence of tube displacement?;First positioning time?; INCLUSION CRITERIA: 1.? Aged 18 to 75 years, with ASA classification I to III; 2.? Elective left‐sided thoracoscopic surgery (lobectomy, segmentectomy or wedge resection); 3. Preoperative three‐dimensional reconstruction of chest CT shows that the distance from the tracheal carina to the distal edge of the opening of the right upper lobe is >= 20mm; 4. Voluntarily sign the informed consent form.?