In the female patient after a lingula-sparing left upper lobectomy scheduled for robot-assisted thoracic surgery, a standard left-sided DLT was selected because remarkable bronchial angulation was absent. Actually, OLV was possible while she was placed in the lateral position. However, it became impossible after the lateral jackknife positioning.
A lingula-sparing left upper lobectomy can be indicated for early-stage lung cancer in the left upper division . Although no previous study has addressed bronchial angulation after this procedure, it would be less significant after this procedure than a left upper lobectomy, given the extents of lung resection. Actually, her bronchial angulation was not remarkable.
In the previous study in patients after a left upper lobectomy, ventilation failure with a standard left-sided DLT occurred in patients with remarkable angulation when they were placed not in the supine position but in the lateral position . In the present patient without remarkable angulation, ventilation failure occurred when she was placed not in the lateral position but in the lateral jackknife position. The lateral position may exacerbate bronchial angulation because this position results in lung compression by the mediastinum and diaphragm . Possibly, compression by the mediastinum exacerbates bronchial angulation, whereas compression by the diaphragm somewhat counteracts this exacerbation. The lateral jackknife position may exacerbate bronchial angulation further, because this position attenuates lung compression by the diaphragm due to a caudal shift of abdominal contents.
The present patient had a 3.4-cm distance from the trachea to the angulation point, suggesting that the tip of the 35-Fr Blue Line® DLT with a 3-cm bronchial port was located around the angulation point when the tube was correctly placed so that the endobronchial cuff was seen approximately 5 mm below the carina . Therefore, the tube tip could be obstructed by the bronchial wall when the left main bronchus was bent more acutely due to the lateral jackknife position. Actually, the tube outlet was obstructed by the bronchial wall.
In such situations, a goal to prevent tube obstruction by placing the tube tip far above the angulation point  is achieved more easily with the Silbroncho® tube having a 2-cm bronchial port than standard left-sided DLTs having 3- or 3.5-cm bronchial ports , since the mean distance to the angulation point was 3.51 cm in the previous 18 patients after the lobectomy . Likewise, a goal to prevent tube obstruction by placing the tube tip below the angulation point is achieved more easily with the Silbroncho® tube, since the flexible, wire-reinforced bronchial port allows it to follow the deformed bronchus without kinking , whereas inflexible, longer bronchial ports of standard left-sided DLTs may easily kink when they are involved in a posture-induced exacerbation of bronchial angulation. Because successful placement of the tube tip far above the angulation point may not always ensure successful OLV when exacerbated bronchial angulation causes severe bronchial kinking , we purposefully selected the larger 37-Fr Silbroncho® tube and placed its tip between the angulation point and secondary carina in an attempt to prevent tube obstruction by the bronchial wall, kinking of the tube, and even kinking of the bronchus.
Options alternative to this tube include a right-sided DLT , a bronchial blocker inserted through a single-lumen tube or DLT , and a single-lumen wire-reinforced tube placed in the left main bronchus . However, the single-lumen tube is cumbersome to use because its withdrawal and advancement under bronchoscopic guidance must be repeated during inflation-deflation cycles repeated for the assessment of surgical air leaks. Right-sided DLTs are more difficult to position for adequate lung isolation and ventilation of the right upper lobe, compared with left-sided DLTs [12, 13]. With a bronchial blocker, deflation of the isolated lung is slower and suctioning beyond the blocker is less effective, compared with DLTs . An endobronchial cuff of a right-sided DLT or bronchial blocker is easier to dislodge during surgical manipulation of the right lung, compared with left-sided DLTs . Therefore, the Silbroncho® left-sided DLT seemed a suitable option, although bronchoscopic guidance is more frequently required for its correct placement, e.g., by preventing intra-tracheal kinking of its flexible bronchial port, compared with standard DLTs .
In a female after a lingula-sparing left upper lobectomy without remarkable bronchial angulation, ventilation failure with a standard left-sided DLT developed after she was placed in not the lateral but lateral jackknife position. Eventually, successful OLV could be achieved with the Silbroncho® left-sided DLT. Our experience suggests that ventilation failure with standard left-sided DLTs can develop more easily when patients with left bronchial angulation are placed in the lateral jackknife position required for robotic surgery than in the lateral position used for more conventional thoracic surgery. The Silbroncho® left-sided DLT is useful to overcome such problems.