Macintosh laryngoscope and i-view™ and C-MAC® video laryngoscopes for tracheal intubation with an aerosol box: a randomized crossover manikin study

Background: We tested the hypothesis that the C-MAC (R) video laryngoscope (C-MAC) with an external display is more useful than the disposable i-view (TM) video laryngoscope (i-view) with an integrated display or a Macintosh direct laryngoscope (Macintosh) for tracheal intubation with an aerosol box. Methods: In this randomized, crossover manikin study, we recruited 37 medical personnel with > 2 years of dedicated anesthesia experience from five hospitals. After the three successful intubations within 60 s using each laryngoscope without a box, the participants performed tracheal intubation thrice with each laryngoscope with at least 2-h intervals in a determined order. The primary outcome was the intubation time. The secondary outcomes were success rate, Cormack-Lehane grade, and subjective difficulty scale score. Results: Thirty-seven personnel (11 women and 26 men) with 12 [5-19] (median [interquartile range]) years of anesthesia and intensive care experience were enrolled. There was no significant difference in the intubation time: 30 [26-32] s for Macintosh, 29 [26-32] s for i-view, and 29 [25-31] s for C-MAC (P = 0.247). The success rate was 95-100%, without a significant difference (P = 0.135). The i-view and C-MAC exhibited superior Cormack-Lehane grades and lower subjective difficulty scale scores than the Macintosh; however, there were no differences between the i-view and C-MAC. Conclusions: Rapid and highly successful tracheal intubation was possible with both Macintosh, i-view, and C-MAC on a normal airway manikin in an aerosol box. Improved Cormack-Lehane grade and the ease of performing the procedure may support the use of video laryngoscopes.