GlideScope Cobalt Videolaryngoscope: Mirrors and Illusions

The GlideScope Cobalt videolaryngoscope (Verathon Medical, Bothell, WA) has become a popular teaching tool because of the ability of the instructor to share the same view as the trainee.^1–3  During use of the GlideScope Cobalt videolaryngoscope size-2 blade, we noticed a reflected image of the vocal cords when the blade tip was used to lift the epiglottis. The figure shows the glottis with open vocal cord and a feeding tube entering the esophagus inferiorly. The epiglottis is elevated by the GlideScope blade and the faint horizontal white line seen within the glottic opening represents the blade tip. The image above the white line is a reflected (mirrored) image of the glottis below. Attempts to advance the breathing tube toward the mirrored (false) view of the glottis would fail and could lead to misplacement of the tracheal tube, multiple intubation attempts, and potential patient harm. The supplemental video demonstrates the reflected image on the blade tip above the real glottis (see Supplemental Digital Content 1, https://links.lww.com/ALN/B39).

The GlideScope Cobalt videolaryngoscope size-2 blade has a reflective surface which may cause confusion for novices during tracheal intubation. Many teachers of videolaryngoscopy instruct learners to direct the tube toward the anterior commissure of the glottis. With this blade, the tube would be directed toward the reflected image and not the actual glottis. Instructors of videolaryngoscopy should be aware of this unique artifact and instruct trainees accordingly.

The authors thank Lemuel White (Karl Storz Endoscopia America, Inc.; and The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania) and James McDaniels, B.S. (The Children’s Hospital of Philadelphia), for their technical assistance.

The authors declare no competing interests.