The anatomical landmarks for positioning of double lumen endotracheal tube using flexible bronchoscopy: A prospective observational study

BACKGROUND: To examine the tracheobronchial anatomy and its common variations after double-lumen tube (DLT) placement, and to determine the anatomical landmarks that can be easily identified by practitioners for DLT positioning. METHOD: In total, 200 patients with American Society of Anesthesiologists I–II, who were aged 20–75 years and scheduled for video-assisted thoracic surgery (VATS), were prospectively enrolled. The types of DLT position in each patient was recorded [Type I, the DLT bronchial end was in the left main bronchus (LMB), and the primary carina could be observed; Type Ⅱ, the DLT bronchial end was in the right bronchus intermedius (RBI); and Type III, an unidentified trachea or bronchus wall was observed from the DLT tracheal lumen] and the main tracheobronchial tree images were collected using Flexible bronchoscopy (FB). RESULT: Five patients were excluded due to excessive bronchus secretions impacting image collection. Type Ⅰ, II, and III positions of DLT were detected in 134 (68.7%) patients, 28 (14.4%) patients, and 33 (16.9%) patients, respectively. Examples of the tracheobronchial tree, common features, and variations in each lung lobe were demonstrated using FB. Furthermore, image analysis showed that each superior segment orifice of the right lower lobe (RLL) and the left lower lobe (LLL) was less variable and recognizable, determining it an important anatomical landmark for DLT positioning. CONCLUSION: The tracheobronchial tree and its common variations after DLT placement were described. The superior segment orifice of the RLL and LLL can be considered as an important landmark for DLT positioning.