Comparison of Time to Intubation of a Double-Lumen Endobronchial Tube Utilizing C-MAC® Versus GlideScope® Versus Macintosh Blade: A Randomized Crossover Manikin Study.

Abstract

Macintosh blade direct laryngoscopy is widely used for endotracheal intubation. It may, however, provide an incomplete view of the glottis in patients with challenging airway anatomy. Consequently, various video laryngoscopes have been developed to enhance the visualization of the glottis and facilitate intubation. Yet, the effectiveness of these video laryngoscopes for intubation using a double-lumen endotracheal tube (DLT), which is longer, larger, and more rigid and has a linear configuration as opposed to the naturally semicircular curvature of a single-lumen endotracheal tube, remains uncertain. We hypothesized that video laryngoscopes would be more efficient for DLT intubation compared to the Macintosh blade in an adult manikin. Ninety-four anesthesia providers, comprising 67 residents, 15 fellows, and 12 attendings, attempted to intubate an adult manikin with normal airway anatomy (Laerdal, Wappingers Falls, NY, USA) using a 37 Fr left-sided DLT. Three different intubation devices were used: the C-MAC® video laryngoscope (Karl Storz GmbH & Co. KG, Tuttlingen, Germany), the GlideScope® video laryngoscope (Verathon Inc., Bothell, WA), and the Macintosh blade direct laryngoscope-were used. Each participant intubated a manikin once with each of the three devices. Participants were randomized via a crossover design with the order of devices determined by using a Latin square design. Time to intubation and the number of failed intubations (esophageal intubation) were compared across the three different devices. Mean times to intubation for the C-MAC®, GlideScope®, and Macintosh blades were 18.57 ± 0.77, 36.26 ± 2.69, and 20.76 ± 0.96 seconds, respectively. There was a statistically significant difference (P<0.001) between the GlideScope® and the other two laryngoscopes. The times for C-MAC® and Macintosh blades were not significantly different. There were two instances of first-attempt failed intubation with the Macintosh. Both the C-MAC® and the Macintosh blades proved more efficient in terms of time to DLT intubation in the manikin with normal airway anatomy, when compared to the GlideScope®. Considering the occurrence of first-attemptfailed intubation, the C-MAC® was the most effective device among the three laryngoscopes for timely successful DLT intubation in the adult manikin. Further studies are needed to confirm these results in human subjects.