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 < 0.001). There were no significant differences between the two groups in the overall intubation success rate, time to intubation, and incidence or severity of other intubation-related complications.

Conclusions: For videolaryngoscopic intubation in patients with a cervical collar, channelled Macintosh-type blades are an alternative to nonchannelled Macintosh-type blades, with a noninferior initial intubation success rate and a lower incidence of subglottic injury.

Study registration: CRIS.nih.go.kr ( KCT0005186 ); first submitted 29 June 2020.