Objective: This systematic review and meta-analysis aimed to determine whether a specific videolaryngoscopy technique is superior to standard direct laryngoscopy using a Macintosh blade to reduce the risk of difficult intubation in surgical and intensive care unit patients.
Materials and methods: We identified all randomized controlled trials comparing videolaryngoscopes (VLSs) to direct laryngoscopy in the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE (from inception to April 2020). The primary outcome was difficult intubation in adult surgical and intensive care unit patients. Secondary outcomes were successful intubation at the first attempt, airway trauma, sore throat, hoarseness, hypoxia, and mortality.
Results: We included 97 randomized controlled trials to evaluate 12775 patients. A high risk of bias was found in at least 50% of the included studies for each outcome. VLSs reduced the risk of difficult intubation compared to direct Macintosh laryngoscopy (RR 0.48, 95% CI from 0.35 to 0.65). VLSs increased the rate of successful intubation at the first attempt when compared to direct Macintosh laryngoscopy (RR 1.03, 95% CI from 1.00 to 1.07). Lower risks of airway trauma were found with VLSs (RR 0.69, 95% CI from 0.55 to 0.86). A decreased risk of hoarseness was associated with the use of VLSs (RR 0.67, 95% CI from 0.54 to 0.83). In addition, VLSs did not significantly reduce the risk of hypoxia compared with direct laryngoscopy (RR 0.83, 95% CI from 0.60 to 1.16).
Conclusions: In this systematic review and meta-analysis, we found that the use of VLSs reduced the risk of difficult intubation and slightly increased the ratio of successful intubation at the first attempt among adult patients.