Comparison of the Effectiveness of the Miller Laryngoscope and the McGrath-MAC Video Laryngoscope in Direct Visualization of the Glottic Opening.

Abstract

Background and Objective: Placing the laryngoscope blade directly under the epiglottis (known as the direct view (DV) method) during videolaryngoscopy offers a superior view of the glottis when compared to the indirect method of lifting the epiglottis by positioning the Macintosh blade tip over the vallecula. While there are few studies comparing glottic views using Miller and Macintosh blades in pediatric patients, we have not come across such a study in adults. In this study, we aimed to compare the effectiveness and hemodynamic responses of the Miller laryngoscope and the McGrath-MAC videolaryngoscope (VL) in visualizing the glottic opening using the DV method. Material and Methods: A prospective study was conducted between August and December 2022 at XXX Hospital on 85 patients scheduled for surgical procedures involving endotracheal intubation. Patients were divided into two groups: Miller laryngoscope (Group M) and McGrath-MAC videolaryngoscope (Group VL) and intubated using the direct lifting method of the epiglottis. Hemodynamic responses before and after induction, as well as during laryngoscopy, intubation time, number of attempts, Cormack and Lehane (C&L) score, percentage of glottic opening (POGO), duration of the view of the opening, and need for external laryngeal pressure during intubation were recorded. Results: Both laryngoscopes showed similar effectiveness in terms of POGO and C&L score when used with the direct lifting method of the epiglottis. The median POGO values according to the DV method were 80% in Group M and 70% in Group VL (p = 0.099). Hemodynamic responses, intubation time, number of attempts, duration of view of the glottis opening, and the need for external laryngeal pressure were similar between the groups. Conclusions: Due to its ability to provide effective intubation conditions, we believe that the McGrath-MAC VL, when used with the indirect view method, can also be utilized in anesthesia practices alongside the DV method.