Augmentation of curved tip of left-sided double-lumen tubes to reduce right bronchial misplacement: A randomized controlled trial

Abstract

Background: During intubation with a blind technique, a left-sided double-lumen tube (DLT) can be misdirected into the right bronchus even though its curved tip of the bronchial lumen turns to the left. This right bronchial misplacement may be associated with the tip angle of DLTs. We thus performed a randomized trial to test the hypothesis that the DLT with an acute tip angle enters the right bronchus less frequently than the tube with an obtuse tip angle.

Methods: We randomized surgical patients (n = 1427) receiving a polyvinyl chloride left-sided DLT. Before intubation, the curved tip was further bent to an angle of 135° and kept with a stylet inside in the curved-tip group, but not in the control group. After the tip was inserted into the glottis under direct or video laryngoscopy, the stylet was removed and the DLT was advanced into the bronchus with its tip turning to the left. We checked which bronchus was intubated, and the time and number of attempts for intubation. After surgery, we assessed airway injury, sore throat, and hoarseness. The primary outcome was the incidence of right bronchial misplacement of the DLT.

Results: DLTs were misdirected into the right bronchus more frequently in the control group than in the curved-tip group: 57/715 (8.0%) vs 17/712 (2.4%), risk ratio (95% CI) 3.3 (2.0-5.7), P < 0.001. The difference was significant in the use of 32 (P = 0.003), 35 (P = 0.007), and 37 (P = 0.012) Fr DLTs. Intubation required longer time (P < 0.001) and more attempts (P = 0.002) in the control group. No differences were found in postoperative airway injury, sore throat and hoarseness.

Conclusions: Before intubation of left-sided DLTs, augmentation of the curved DLT tip reduced the right bronchial misplacement and facilitated intubation without aggravating airway injury.

Fig 1. CONSORT flow diagram.

Fig 2

A 37-Fr double-lumen tube with its bronchial tip bent to an angle of 135° (A) and a tube without any modification to the tip (B).

Fig 3

Mean time (A) and number of attempts (B) for intubation of left-sided double-lumen tubes in patients with each grade of laryngoscopic view. Error bars are standard deviations. P values were obtained by comparing the intubation time between groups using unpaired t-tests (A) and by comparing the number of intubation attempts using Fisher’s exact tests (B).

Fig 4. The site and type of postoperative airway injury.

P values were obtained by comparing the incidence of airway injury between groups using Fisher’s exact tests.

Fig 5

The incidence and severity of sore throat (A) and hoarseness (B) one hour, one and two days after extubation of left-sided double-lumen tubes. P values were obtained by comparing the incidence of sore throat (A) and hoarseness (B) between groups using Fisher’s exact tests.

Fig 6

A diagram showing that the more curved tip of the left-sided double-lumen tube (A) is further extended to the left bronchial opening over the carina compared with the less curved tip (B).