BACKGROUND: Videolaryngoscopes are aggressively marketed, but independent evaluation in difficult airways is scarce. This multicentre, prospective randomized controlled trial evaluates six videolaryngoscopes in patients with a simulated difficult airway.
METHODS: With ethics committee approval and written informed consent, 12 senior anaesthetists intubated the trachea of 720 patients. A cervical collar limited mouth opening and neck movement, making intubation difficult. We evaluated three unchannelled (C-MAC? D-blade, GlideScope?, and McGrath?) and three channelled videolaryngoscopes (Airtraq?, A.P. Advance? difficult airway blade, and KingVision?). The primary outcome was first-attempt intubation success rate. Secondary outcomes included overall success rate, laryngeal view, intubation times, and side-effects. The primary hypothesis for every videolaryngoscope was that the 95% confidence interval of first-attempt success rate is ≥90%.
RESULTS: Mouth opening was decreased from 46 (sd 7) to 23 (3) mm with the cervical collar. First-attempt success rates were 98% (McGrath?), 95% (C-MAC? D-blade), 87% (KingVision?), 85% (GlideScope? and Airtraq?), and 37% (A.P. Advance?, P<0.01). The 95% confidence interval of first-attempt success rate was >90% only for the McGrath?. Overall success, laryngeal view, and intubation times differed significantly between videolaryngoscopes (all P<0.01). Side-effects were minor.
CONCLUSIONS: This trial revealed differences in the performance of six videolaryngoscopes in 720 patients with restricted neck movement and limited mouth opening. In this setting, first-attempt success rates were 85-98%, except for the A.P. Advance? difficult airway blade. Highest success and lowest tissue trauma rates were achieved by the McGrath? and C-MAC? D-blade, highlighting the importance of the videolaryngoscope blade design.
CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: identifier NCT01692535.