Video laryngoscopy and external laryngeal manipulation

Abstract

Editor—We read with interest the article written by Groeben and colleagues,1Jungbauer A Schumann M Brunkhorst V Borgers A Groeben H Expected difficult tracheal intubation: a prospective comparison of direct laryngoscopy and video laryngoscopy in 200 patients.Br J Anaesth. 2009; 102: 546-550Crossref PubMed Scopus (146) Google Scholar comparing direct laryngoscopy with video laryngoscopy in expected difficult tracheal intubations. We also have used the Storz video laryngoscope in our institution and found it a very useful tool for difficult intubations and for teaching, not only for novice anaesthetists, but also for anaesthetic assistants, as they too are able to visualize the view of the glottis during external manipulation of the larynx and when applying cricoid pressure for rapid sequence inductions. We have found that the assistant is able to optimize the view of the glottis for the anaesthetist by directly visualizing the view on the portable screen, and not rely solely on feedback from the anaesthetist, as with conventional direct laryngoscopy. In their study, Groeben and colleagues fail to say whether the assistant performing the external manipulation was allowed to see the view obtained on the screen in the video laryngoscope group. It would be interesting to know whether a subanalysis of this group of patients would show a significant difference in the grade of the view obtained and success of tracheal intubation, as the direct feedback obtained from the video laryngoscope allows the assistant to provide a much better and coordinated view for the anaesthetist during external laryngeal manipulation. Do the authors agree and did they consider a subanalysis of this group in their study? In the study, a subanalysis of the patients with Cormack and Lehane grade III and IV was performed and this showed a significant difference in the intubation time, in favour of the video laryngoscope group and a significantly better rate of successful intubation. They also found that fewer manipulations were required in this group. The authors, however, failed to state how many of the cases in this subanalysis group required external laryngeal manipulation, although the need for optimizing manoeuvres was mentioned. These significant differences could be attributed to a poorer view of the glottis obtained as a result of ‘blind’ external manipulation in the direct laryngoscope group compared with the video laryngoscope group, where there is improved coordination between both the assistant and the anaesthetist as a result of the image seen on the monitor, which has been shown to result in a significant advantage over the conventional laryngoscope technique.2Kaplan MB Ward DS Berci G A new video laryngoscope—an aid to intubation and teaching.J Clin Anesth. 2003; 14: 620-626Abstract Full Text Full Text PDF Scopus (132) Google Scholar Finally, do the authors feel that they could also conclude that the use of the video laryngoscope eases external laryngeal manipulation, especially in anticipated difficult intubation? H. Groeben* A. Jungbauer M. Schumann V. Brunkhorst A. Börgers Essen, Germany *E-mail: [email protected] Editor—We thank Dr Ahmad and his colleagues for their comments and questions concerning our article.1Jungbauer A Schumann M Brunkhorst V Borgers A Groeben H Expected difficult tracheal intubation: a prospective comparison of direct laryngoscopy and video laryngoscopy in 200 patients.Br J Anaesth. 2009; 102: 546-550Crossref PubMed Scopus (146) Google Scholar They stress the impact of an optimized view by the assistance for intubation on the success rate and time for intubation, and whether the assisting staff shared the view on the monitor of the video laryngoscope. To maximize the benefit of the technique, the assisting staff did share the view on the monitor. We agree that the change from a blinded assistant to a seeing one improves the success. However, this effect cannot be quantified from our study, and would require a different study design. For a proper analysis, all the intubation would need to be performed with the video laryngoscopy with either blind or seeing assistant staff. In our study, the difference between the conventional technique and the improved view with the video laryngoscope was in our opinion more important than the difference in the view of the assistant staff. Overall, we think the improved view for the assistant staff contributes to the positive result, but the extent of this effect cannot be analysed from our study. To clarify this question, further research is required.