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Classification of videolaryngoscopes is crucial

2017; Elsevier BV; Volume: 118; Issue: 5 Linguagem: Inglês

10.1093/bja/aex112

1471-6771

Erol Cavus, Christian Byhahn, Volker Dörges,

Anesthesia and Sedative Agents

Editor—We read with interest the article by Kleine-Brueggeney and colleagues,1Kleine-Brueggeney M Greif R Schoettker P Savoldelli GL Nabecker S Theiler LG. Evaluation of six videolaryngoscopes in 720 patients with a simulated difficult airway: a multicentre randomized controlled trial.Br J Anaesth. 2016; 116: 670-679Abstract Full Text Full Text PDF PubMed Scopus (121) Google Scholar who compared six videolaryngocopes during routine airway management in patients with simulated difficult airways. We congratulate the authors for undertaking this study, because a comparison of six different devices in a clinical setting is ambitious. In addition, because of the growing availability of different videolaryngoscopes on the market, a comparison of both intubation success and handling between the different devices is of great importance. Nevertheless, after carefully reading the article, we believe that there are some aspects that need to be addressed further. These authors compared the videolaryngoscopes by A.P. Advance, C-MAC D-Blade, McGrath, KingVision, Airtraq, and GlideScope in patients with simulated limited mouth opening and neck movement. The videolaryngoscopes that performed best were the McGrath and the C-MAC D-Blade; the McGrath was the only videolaryngoscope that reached the hypothesized first-attempt success rate of 0.9 within the predefined confidence interval. According to the authors, the videolaryngoscopes were chosen to represent three channelled and three non-channelled devices. However, the blade design of the videolaryngoscopes differed in another important aspect that is not addressed further by the authors. Of the six videolaryngoscopes, there are five with highly angulated blades, namely C-MAC D-Blade, GlideScope, KingVision, Airtraq, and A.P. Advance with difficult airway blade. In contrast, the McGrath as the sixth videolaryngoscope was chosen with a MAC blade. Even though the authors stated in their methodology paper2Theiler L Hermann K Schoettker P et al.SWIVIT–Swiss video-intubation trial evaluating video-laryngoscopes in a simulated difficult airway scenario: study protocol for a multicenter prospective randomized controlled trial in Switzerland.Trials. 2013; 14: 94Crossref PubMed Scopus (18) Google Scholar that the McGrath MAC is a further development of the original McGrath Series 5, the blade design of the two series differs significantly. The McGrath MAC used in the present study has a Macintosh-type blade that is very similar to a conventional laryngoscope blade that anaesthesiologists use in their daily practice. In contrast, the McGrath Series 5 has a highly angulated blade that would have compared much better with the other five videolaryngoscopes in the present study. Thus, one Macintosh-type blade almost every anaesthesiologist is familiar with was compared with five curved blades. Proper handling of curved blades requires a significant amount of training. The important difference between Macintosh-type and highly angulated blades with regard to handling and intubation success has been addressed by several studies.3Teoh WHL Saxena S Shah MK Sia ATH. Comparison of three videolaryngoscopes: Pentax Airway Scope, C-MAC™, Glidescope® vs the Macintosh laryngoscope for tracheal intubation.Anaesthesia. 2010; 65: 1126-1132Crossref PubMed Scopus (82) Google Scholar4Alvis BD Hester D Watson D Higgins M St Jacques P. Randomized controlled trial comparing the McGrath MAC video laryngoscope with the King Vision video laryngoscope in adult patients.Minerva Anestesiol. 2016; 82: 30-35PubMed Google Scholar However, this aspect was not addressed further in the present study. Readers might become puzzled because of the incomplete description of the videolaryngoscopes used in this study. In the flowchart, use of the C-MAC is clearly stated as D-Blade, both GlideScope and Airtraq are self-explainable curved blades, and the McGrath blade type has been discussed above. However, A.P. Advance and KingVision have no further description of their blade types, at least in the flowchart, so that it is not clear whether the A.P. Advance is used with the Mac-blade (as usually done) or the difficult airway blade, and the KingVision could also be used with a non-channelled blade. Exact classification of the studied material is of paramount importance, especially for A.P. Advance and KingVision, for which few data are available. Finally, the number of missing data for insertion of the device into the oropharynx, quality of view, and ease of tube insertion are not proportional between the different devices tested, and ranges between 9 (A.P. Advance) and 0 (McGrath). None declared.