New Video and Optical Laryngoscopes Beat the Macintosh
The McGrath, Airtraq, and GlideScope laryngoscopes were all preferred over the Macintosh.
Several optical and video-based laryngoscopes have recently become available. The notable advantage of these new devices over direct laryngoscopy is that they do not require alignment of the oral and laryngeal axes in such a way as to create a straight line of sight to the vocal cords. In a simulator-based trial, researchers conducted a head-to-head comparison of three of the most popular devices (the McGrath, Airtraq, and GlideScope) with the Macintosh laryngoscope.
Sixty anesthesia providers (faculty, residents, and nurses) who had experience with Macintosh direct laryngoscopy but not with video or optical scopes received individualized training in use of the devices, followed by five practice intubation attempts with each device on a simulated normal airway. Each provider then attempted intubation in three simulated difficult airway scenarios: pharyngeal obstruction, pharyngeal obstruction with cervical spine rigidity, and tongue edema. The Macintosh laryngoscope was always used first, and the order of use of the other three devices was randomized. For each intubation attempt, laryngeal grade of view, time to intubation, success rate, and subjective rating of difficulty were measured.
In all three difficult airway scenarios, the alternative scopes provided significantly better laryngeal views than the Macintosh did. Of the alternative devices, the Airtraq and the McGrath provided significantly better laryngeal views than the GlideScope did. Time to intubation for each device varied according to the airway scenario: The Macintosh and Airtraq laryngoscopes were significantly faster than the other devices in the two pharyngeal obstruction scenarios, whereas the Airtraq was fastest and the Macintosh was slowest in the most difficult scenario (tongue edema). In the tongue edema scenario, the Macintosh was associated with a high rate of failure (37%) compared with the GlideScope (2%), the Airtraq (2%), and the McGrath (0%). All three of the alternative laryngoscopes were judged by providers as easier to use than the Macintosh.
Comment: In this small, simulator-based trial with anesthesia providers who were skilled in use of the standard Macintosh laryngoscope, the video and optical scopes performed better and were preferred over the antiquated Macintosh. Although an airway simulator does not exactly represent human anatomy or real patients (it is neither wet nor bloody), this study highlights some distinct advantages related to improved laryngeal view obtained with video or optical laryngoscopy. If you haven't already tried video or optical laryngoscopy, do!
Aaron E. Bair, MD, MSc, FAAEM, FACEP
Published in Journal Watch Emergency Medicine December 19, 2008
Citation(s): Savoldelli GL et al. Comparison of the Glidescope®, the McGrath®, the Airtraq® and the Macintosh laryngoscopes in simulated difficult airways. Anaesthesia 2008 Dec; 63:1358.