Effect of bevel direction on the tracheal tube pathway during nasotracheal intubation

BACKGROUND For nasotracheal intubation, the nasal pathway between the inferior turbinate and hard palate (lower pathway) is preferred for patient safety. However, selecting the lower pathway can be challenging because passage of the tube through the nasal pathway is usually performed blindly. OBJECTIVES We investigated whether facing the bevel of the tracheal tube in the cephalad direction of the patient could help in advancing the tracheal tube through the lower pathway during nasotracheal intubation. DESIGN A randomised, blinded trial. SETTING SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea from January 2019 to March 2020. PATIENTS Sixty-eight adult patients undergoing oromaxillary surgeries were enrolled in this study. INTERVENTIONS Patients were randomly allocated to undergo nasotracheal intubation with the bevel of the tube facing the cephalad direction (intervention group) or to the left (conventional group). MAIN OUTCOME MEASURES The effects of bevel direction on the pathway of the tube in the nasal cavity, and the incidence of epistaxis were evaluated by fibreoptic bronchoscopy. RESULTS The success rate of the tracheal tube passing through the lower pathway was significantly higher in the intervention group than the conventional group (79.4 vs. 55.9%, relative risk 1.421, 95% CI 1.007 to 2.005, P = 0.038). The incidence of epistaxis was also lower in the intervention group than in the conventional group (41.2 vs. 73.5%, relative risk 0.560, 95% CI 0.357 to 0.878, P = 0.007). CONCLUSIONS Facing the bevel of the tracheal tube in the cephalad direction of the patient facilitated selection of the lower pathway and reduced the incidence of epistaxis during nasotracheal intubation in patients undergoing oromaxillary surgery. TRIAL REGISTRATION ClinicalTrial.gov, NCT03740620.