Videolaryngoscope designs for tracheal intubation in adults: a systematic review with network meta-analysis of randomised controlled trials

Introduction Videolaryngoscopy improves tracheal intubation outcomes compared with direct laryngoscopy in various scenarios. However, the range of videolaryngoscope designs makes it challenging to identify the most effective device. We conducted a systematic review and network meta-analysis to compare different laryngoscope designs when used for tracheal intubation of adults under general anaesthesia. Methods We searched six databases for randomised controlled trials of patients aged >= 16 years, requiring tracheal intubation under general anaesthesia and evaluating comparisons between the following interventions: channelled videolaryngoscopes; Macintosh blades; hyperangulated blades; video stylets; and direct laryngoscopes. The primary outcome was the incidence of failed first tracheal intubation attempts. Secondary outcomes included failed tracheal intubation; tracheal intubation difficulty; glottic view; time to tracheal intubation; and incidence of complications. Results We included 294 studies evaluating 44,284 patients. Channelled blades (OR (95%CrI) 0.37 (0.27-0.50), moderate certainty), Macintosh blades (OR (95%CrI) 0.45 (0.31-0.64), moderate certainty) and hyperangulated videolaryngoscopes (OR (95%CrI) 0.51 (0.39-0.68), moderate certainty) reduced the incidence of failed first tracheal intubation significantly compared with direct laryngoscopes, with channelled-blade devices ranking highest for this outcome. No significant difference was observed between video stylets and direct laryngoscopes for this outcome (OR (95%CrI) 0.67 (0.16-3.00), low certainty). All three videolaryngoscope designs also reduced failure rates across second and third tracheal intubation attempts; decreased the likelihood of difficult tracheal intubation; improved glottic view; and lowered the incidence of oesophageal intubation and airway tissue damage. Channelled- and hyperangulated-blade videolaryngoscopes significantly improved glottic view compared with Macintosh-blade designs. Discussion We are moderately certain that the three designs of videolaryngoscopes enhance tracheal intubation effectiveness, safety and postoperative recovery compared with direct laryngoscopes. Channelled videolaryngoscopes and hyperangulated blades might provide superior glottic views compared with Macintosh-blade videolaryngoscopes. No definitive conclusions can be drawn regarding the comparative tracheal intubation performance across different video-assisted devices and designs.