90° versus 110° rotation of left double lumen tube for endobronchial intubation: a randomized controlled trial

It is conventional that anesthesiologist rotates the left double lumen tube (DLT) 90° counterclockwise when the DLT endobronchial cuff crosses beyond the glottis, with which the success rate of left endobronchial intubation on first attempt is 75.9%. However, the true inclination angle of the left main bronchus is 108.4°, so the first attempt success rate of left bronchial intubation by 110° left DLT rotation would be higher than of 90° left DLT rotation. This study aimed to assess whether the first attempt success rate of left bronchial intubation by 110° left DLT rotation was higher than of 90° left DLT rotation.

We conducted a randomized controlled study to compare left DLT 90° versus 110° counterclockwise rotation in adult patients intubated left DLT to undergo elective thoracic surgery. We assessed the first attempt left endobronchial intubation success rate and evaluated the airway injuries at 30 min after the starting of surgery by fiberoptic bronchoscopy and intubation complications such as sore throat and hoarseness at the postoperative 24 h.

A total of 556 patients (56.4±12.3 years of age; 322 women) were included: 275 patients in 90° group and 281 patients in 110° group. The first attempt success rate of left bronchial intubation by left DLT was 87.9% in the 110° group versus 80.7% in the 90° group (P=0.02). The 110° group had lower rate of postoperative sore throat as well (33.9% versus 45.8%, P=0.005). However, the two group had no statistical difference in carina mucosal injury and postoperative hoarseness.

When the endobronchial cuff passed beyond the glottis, the left DLT 110° rotation increased the success rate of the first left bronchus intubation and reduced the incidence of sore throat in adult patients during thoracic surgery using left DLT.

This study was registered at Chinese Clinical Trial Registry (ChiCTR2100053350) on November 19th, 2021.