Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation: a Cochrane Systematic Review.

Difficulties with tracheal intubation commonly arise and impact patient safety. This systematic review evaluates whether videolaryngoscopes reduce intubation failure and complications compared with direct laryngoscopy in adults. We searched CENTRAL, MEDLINE, Embase and clinicaltrials.gov up to February 2015, and conducted forward and backward citation tracking. We included randomized controlled trials that compared adult patients undergoing laryngoscopy with videolaryngoscopy or Macintosh laryngoscopy. We did not primarily intend to compare individual videolaryngoscopes. Sixty-four studies (7044 participants) were included. Moderate quality evidence showed that videolaryngoscopy reduced failed intubations (Odds Ratio (OR) 0.35, 95% Confidence Interval (CI) 0.19-0.65) including in participants with anticipated difficult airways (OR 0.28, 95% CI 0.15-0.55). There was no evidence of reduction in hypoxia or mortality, but few studies reported these outcomes. Videolaryngoscopes reduced laryngeal/airway trauma (OR 0.68, 95% CI 0.48-0.96) and hoarseness (OR 0.57, 95% CI 0.36-0.88). Videolaryngoscopy increased easy laryngeal views (OR 6.77, 95% CI 4.17-10.98) and reduced difficult views (OR 0.18, 95% CI 0.13-0.27) and intubation difficulty, typically using an 'intubation difficulty score' (OR 7.13, 95% CI 3.12-16.31). Failed intubations were reduced with experienced operators (OR 0.32, 95% CI 0.13-0.75) but not with inexperienced users. We identified no difference in number of first attempts and incidence of sore throat. Heterogeneity around time for intubation data prevented meta-analysis. We found evidence of differential performance between different videolaryngoscope designs. Lack of data prevented analysis of impact of obesity or clinical location on failed intubation rates. Videolaryngoscopes may reduce the number of failed intubations, particularly among patients presenting with a difficult airway. They improve the glottic view and may reduce laryngeal/airway trauma. Currently, no evidence indicates that use of a videolaryngoscope reduces the number of intubation attempts or the incidence of hypoxia or respiratory complications, and no evidence indicates that use of a videolaryngoscope affects time required for intubation.