Ensuring direct laryngoscopy will not become an extinct skill

Sir, Andersen et al. in a recent publication demonstrated that although the intubation times with a video-laryngoscope (VLS) [Glidescope® (GS), Verathon Inc., Bothell, WA, USA] were slightly slower than a direct laryngoscope (DL), both scopes performed relatively well in intubating an obese patient population. Furthermore, the laryngeal view was superior with the GS, as was the average score using the Intubation Difficulty Scale (IDS) as developed by Adnet et al. These results are quite consistent with a study we have previously published comparing the use of adjuncts with a variety of VLSs and DL in a similar population of obese patients. In a recent letter, El-Orbany suggests that the results of Andersen et al. support the case for preferentially using a DL for intubation of an obese patient and that the success rate is a function of correct patient positioning (as is applied in the study of Andersen et al.). El-Orbany further details the proclivity of trainees to use a VLS when confronted by an expectedly difficult intubation and the detriment this may have on the skills with DL. We support the opinion of El-Orbany that the retention and development of DL skills are important clinical proficiency for all anaesthesiologists. However, we have some observations regarding his advocacy of DL as the tool of first choice in obese patients and insistence of the importance of patient positioning. Regarding the preferential use of a DL with (obese) patients, we consider this a potential disservice to the patient when a VLS is readily available. Andersen et al. demonstrate that the difference in intubation time between GS and DL is not of clinical consequence, but that the intubation ease as assessed by the IDS was superior with the GS. If the ease of the intubation is greater, then there is a likely improvement of patient safety, not only to be measured in intubation time. Additionally, the better visual quality (larger angle of view with VLS compared with DL) using a VLS lets the anaesthesiologist better navigate the endotracheal tube (ETT), including accurately ensuring correct depth of the ETT. Using a DL is therefore to the detriment of the patient. There is however an alternative that preserves skill in DL whilst offering the advantages of VLS. VLS such as the Storz® C-MAC (Karl Storz, Tuttlingen, Germany) have the full functionality of a VLS whilst maintaining the Macintosh-form-blade form. This facilitates either DL or VLS (to the discretion of the anaesthesiologist, providing two options), the capture of video or still pictures, and is an ideal tool for teaching and learning endotracheal intubation – far superior to the exclusive ‘look over my shoulder’ training available with DL alone. Furthermore, the Macintosh-form blade need not be used in a conjunction with a styletted ETT. The use of a stylet has been associated with serious complications and exclusion of such reduces the dexterous demands of the procedure on the anaesthesiologist. On the second point, intubation ease is not merely a function of patient positioning; as we are sure El-Orbany would concede. It is too simplistic to consider that a DL will be sufficient in cases whereby the degree of difficulty cannot be accurately gauged ex ante. In such cases where a Cormack & Lehane (C&L) grade III or IV is realized, then the procedure is being carried out effectively blind. We rarely encounter a case in which any VLS could only provide a C&L grade IV – although in such situations, the VLS can also prove helpful. Although we agree that ease of endotracheal intubation is not only a function of visual quality, it is an important consideration and clearly promotes use of a VLS. In our opinion, blade designs that provide sufficient illumination for good visualization of the anatomy at the distal end of the blade fit the anatomy of the vast majority of patients (e.g. Macintosh design) and provide the space necessary for use of other adjuncts in cases where endotracheal intubation proves challenging should be the new universal standard in anaesthetic practice.