Channelled versus nonchannelled Macintosh videolaryngoscope blades in patients with a cervical collar: a randomized controlled noninferiority trial

Purpose Channelled blades have the advantage of avoiding stylet use and potential airway injury during videolaryngoscopic intubation. Nevertheless, the effectiveness of channelled Macintosh-type blades has not yet been fully established. We sought to assess the utility of channelled Macintosh-type blades for videolaryngoscopic intubation under cervical spine immobilization. Methods We conducted a randomized controlled noninferiority trial in neurosurgical patients with a difficult airway simulated by a cervical collar. Videolaryngoscopic intubation with a reinforced tracheal tube was performed using a channelled Macintosh-type blade without a stylet (channelled group, n = 130) or a nonchannelled Macintosh-type blade with a stylet (nonchannelled group, n = 131). The primary outcome was intubation success rate. Secondary outcomes included time to intubation and incidence or severity of intubation-related complications (subglottic, lingual, and dental injuries; bleeding; sore throat; and hoarseness). Results The initial intubation success rate was 98% and 99% in the channelled and nonchannelled groups, respectively, showing the noninferiority of the channelled group (difference in proportions −0.8%; 95% confidence interval [CI], −4.8% to 2.9%; predefined noninferiority margin, −5%; P = 0.62). Fewer participants in the channelled group had subglottic injuries than in the nonchannelled group (32% [32/100] vs 57% [54/95]; difference in proportions, −25%; 95% CI, −39% to −11%; P