Glidescope(®) video-laryngoscopy versus direct laryngoscopy for endotracheal intubation: a systematic review and meta-analysis

INTRODUCTION: The Glidescope(®) video-laryngoscopy appears to provide better glottic visualization than direct laryngoscopy. However, it remains unclear if it translates into increased success with intubation. METHODS: We systematically searched electronic databases, conference abstracts, and article references. We included trials in humans comparing Glidescope(®) video-laryngoscopy to direct laryngoscopy regarding the glottic view, successful first-attempt intubation, and time to intubation. We generated pooled risk ratios or weighted mean differences across studies. Meta-regression was used to explore heterogeneity based on operator expertise and intubation difficulty. RESULTS: We included 17 trials with a total of 1,998 patients. The pooled relative risk (RR) of grade 1 laryngoscopy (vs ≥ grade 2) for the Glidescope(®) was 2.0 [95% confidence interval (CI) 1.5 to 2.5]. Significant heterogeneity was partially explained by intubation difficulty using meta-regression analysis (P = 0.003). The pooled RR for nondifficult intubations of grade 1 laryngoscopy (vs ≥ grade 2) was 1.5 (95% CI 1.2 to 1.9), and for difficult intubations it was 3.5 (95% CI 2.3 to 5.5). There was no difference between the Glidescope(®) and the direct laryngoscope regarding successful first-attempt intubation or time to intubation, although there was significant heterogeneity in both of these outcomes. In the two studies examining nonexperts, successful first-attempt intubation (RR 1.8, 95% CI 1.4 to 2.4) and time to intubation (weighted mean difference −43 sec, 95% CI −72 to −14 sec) were improved using the Glidescope(®). These benefits were not seen with experts. CONCLUSION: Compared to direct laryngoscopy, Glidescope(®) video-laryngoscopy is associated with improved glottic visualization, particularly in patients with potential or simulated difficult airways.