Comparison of dental force applied during endotracheal intubation with hyper-angulated and macintosh-type video laryngoscopy blades used by emergency medicine trainees: A randomized cross-over manikin study

This study aimed to compare the effects of Macintosh-type and hyperangulated video laryngoscopy (VL) blades on dental force during endotracheal intubation (ETI) using Glidescope and McGrath VL devices. In this randomized, crossover, manikin study conducted at a university emergency medicine (EM) program, 65 EM trainees included interns and residents performed 520 intubations using four different VL blades (GlideScope VL with Macintosh-type Mac T3 and hyperangular Lo Pro T3 blades and McGrath VL Macintosh-type MAC 4 and hyperangular McGrath X3 blades) in normal and difficult airway scenarios. The primary outcome of this study was the dental pressure (Newton) exerted during ETI. The secondary outcomes included c-spine motion (degree), intubation success (%), duration (seconds), successful glottic view (%), and intubator comfort (7-point Likert). Significant differences were observed in dental force (H(3) = 11.7, P = 0.008), c-spine motion (H(3) = 8.34, P = 0.039), duration (H(3) = 16.56, P = 0.001), and comfort (H(3) = 174.96, P < 0.001) across blade types. Glidescope LoPro T3 provided a significant lower dental force (adjusted P = 0.01), less c-spine motion (adjusted P = 0.031), and shorter intubation duration (adj P < 0.01) than the McGrath Mac 4. First attempt success and intubator comfort were significantly better with all Glidescope blades (z score of 3.7 and 4.7) than with McGrath blades (z score of-4.1 and-4.4). The Glidescope LoPro T3 blade demonstrated advantages in dental force, c-spine motion, and intubation duration compared with McGrath Mac 4. Overall, the Glidescope blades provided superior comfort and higher first attempt success rates.