McGrath videolaryngoscope versus Macintosh laryngoscope for tracheal intubation: A systematic review and meta-analysis with trial sequential analysis

Study objective: The McGrath laryngoscope is a novel self-contained videolaryngoscope with a single-use blade. There are several anecdotal reports that the McGrath is superior to the Macintosh laryngoscope for tracheal intubation. However this remains controversial. Design: Meta-analysis and systematic review. Setting: Operating room or intensive care unit. Measurements: A comprehensive literature search was conducted to identify clinical trials that met our inclusion criteria. To qualify, studies had to be prospective randomized trials comparing tracheal intubation between the McGrath and the Macintosh in an adult population. We extracted data on success rate, glottic visualization during intubation, and intubation time from the studies identified. In subgroup analysis, we assessed the influence on each of these parameters which included airway condition (normal or difficult) and operator (novice or experienced). We then conducted a trial sequential analysis (TSA). Main results: Fourteen articles met our inclusion criteria. The McGrath offered better glottic visualization than the Macintosh (risk ratio, 1.34; 95% confidence interval (CI), 1.25–1.45). However, the McGrath required longer intubation time (mean difference, 10.1 s; CI, 2.74–17.5) and demonstrated similar success rate of tracheal intubation (risk ratio, 1.00; CI, 0.95–1.05) compared to the Macintosh. TSA showed that total sample size reached the required information size (RIS) in glottic visualization and success rate. However, only 15.1% of the RIS was achieved in intubation time. In the subgroup analysis for airway condition and operator experience level, there were no subgroup differences in both glottic visualization and intubation time. Conclusions: Our meta-analysis suggests that the McGrath is superior to the Macintosh in terms of glottic visualization (GRADE: moderate). However, it significantly extends intubation time (GRADE: very low) and its success rate (GRADE: very low) for tracheal intubation is not excellent. TSA suggests that further studies are necessary to confirm the results of intubation time.