This case report suggests that downfolding of the epiglottis into the laryngeal inlet can occur during tracheal intubation when using the McGrath videolaryngoscope and that the downfolded epiglottis can be restored to its original position by gentle glottic exposure using the McGrath blade. Epiglottic downfolding into the laryngeal inlet has been considered to be a rare complication of tracheal intubation [7]. However, as anesthesiologists rarely observe the larynx after tracheal intubation, this prolapse may occur much more frequently than it was currently thought. Although there are fortunately no reports of severe complications associated with the downfolding of the epiglottis, prolonged prolapse of the epiglottis may cause swelling, resulting in airway obstruction [1]. Therefore, if possible, the position of the epiglottis should be carefully observed during tracheal intubation to reduce the risk of prolonged prolapse.
Epiglottic downfolding into the laryngeal inlet has been reported to be associated with blind intubation techniques such as supraglottic airway-guided intubation [3], fiberoptic intubation [4], and light-guided intubation [5, 6] because these techniques do not enable observation of the epiglottis during intubation. However, it can also occur using the Macintosh laryngoscope [1, 2] or the Pentax-AWS which provide better visualization [7]. A previous case series [7] reported that the rate of epiglottis prolapse with the Pentax-AWS was approximately three in 1000 intubations. In these cases, prolapse was caused by the blade of the Pentax-AWS as it passed along the anterior larynx. To prevent this complication, the authors recommended that the Pentax-AWS blade should be advanced along the posterior aspect of the airway as in the laryngeal mask airway insertion technique [7]. Epiglottic downfolding into the laryngeal inlet when using the McGrath videolaryngoscope may be caused by the same mechanism as for the Pentax-AWS (Fig. 2a). Although the typical insertion technique for the McGrath videolaryngoscope differs from that of the AWS in that the tip of the blade is usually inserted into the vallecula, as for the Macintosh laryngoscope, the blade can also be used to elevate the epiglottis directly. When it is necessary to elevate the epiglottis directly, we recommend that the blade should be advanced along the posterior aspect of the airway; in other words, the epiglottis should be lifted from the dorsal side to prevent downfolding (Fig. 2b).
There are no established methods to correct epiglottis prolapse. In previous cases, the epiglottis has been restored to its original position using a McCoy-type laryngoscope [3], a fiberscope [4], endoscopic forceps [6], and partial extubation [1, 2, 5, 7]. In the present case report, the epiglottis prolapse was corrected easily by gentle glottic exposure using the McGrath videolaryngoscope without extubation or the use of any specialized devices. In this case, early detection was a possible reason for success. The problem was easily corrected because the epiglottis was still soft and elastic at the time of detection. If detection is delayed, the epiglottis can become edematous and, thus, more difficult to be restored. Therefore, whenever possible, anesthesiologists should carefully observe the condition of the epiglottis during and immediately after tracheal intubation using the McGrath videolaryngoscope.
In this report, we described a case of epiglottic downfolding into the laryngeal inlet after tracheal intubation using the McGrath videolaryngoscope. After the prolapse, we were able to restore the epiglottis to its original position by gentle glottic exposure using the McGrath videolaryngoscope without removal of the endotracheal tube. During tracheal intubation using the McGrath videolaryngoscope, Macintosh-type glottic exposure and careful observation of the epiglottis can enable the prevention and detection of epiglottis prolapse.