Is the Mcgrath[R] Videolaryngoscope a Low-Efficiency Device for Inexperienced Anaesthetists Performing Tracheal Intubation? (Correspondence) (Letter to the Editor‪)‬

We read with concern the recent article of Sharma et al (1) comparing the Pentax Airway Scope[R] and McGrath[R] videolaryngoscope (MVL) with the Macintosh laryngoscope in tracheal intubation by anaesthetists unfamiliar with videolaryngoscopes in a manikin study. The results of this study showed that only 48% of participants could intubate within three minutes using the MVL and required a median of three attempts. For this reason, the authors concluded that in the manikin model of urgent intubation, anaesthetists unfamiliar with videolaryngoscopes could not successfully intubate the trachea with the MVL. Their findings are no different from results of the two previous studies in which the tracheal intubation was also performed by inexperienced anaesthetists in humans and manikins (2,3). A randomised, controlled clinical trial in anaesthetised adult patients showed that the time required for intubation by inexperienced anaesthetists was significantly longer in the MVL group than in the Macintosh laryngoscope (ML) group, but there were no significant differences in the grade of laryngoscopy view, number of laryngoscopies or complications etc. Also, there was no differential learning effect between the MVL and ML (2). By a randomised cross-over comparative study in manikins, Ray et al (3) demonstrated that novices were more successful and caused less dental trauma with the MVL compared with the ML. Intubation times and ease of use for each laryngoscope were similar. After analysing the design of these studies, we found that Sharma et al (3) did not clearly describe whether a shaped stylet was inserted into the tracheal tube during intubations with the MLV. It has been shown that a curved stylet is necessary for successful intubation with the MVL (4,5). As the airway axes are not aligned, the tip of the tracheal tube must reverse the curvature of the MVL blade to enter the larynx. Mounting the tracheal tube onto a stylet and angling the distal tip upwards by 60 to 70 degrees helps to overcome this problem. Previous studies have demonstrated that when a curved stylet is not used, intubation with the MVL is associated with a relatively high failure rate (59 to 76%) (4,5). Therefore, we speculate that a high incidence of failed intubation with the MVL in this study (52%) may be contributed to an incorrect methodology, rather than a real low performance of the MVL. Before this issue is clarified, the conclusion that the MVL is a low-efficiency device for inexperienced anaesthetists to perform tracheal intubation should be interpreted with caution.