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the use of advanced airway management devices in clinical practice

Batuwitage, Bisanth; Nishikawa, Koji; Mercer, Simon; McDonald, Andrew; Charters, Peter

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European Journal of Anaesthesiology: June 2016 - Volume 33 - Issue 6 - p 470-471
doi: 10.1097/EJA.0000000000000422
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We would like to thank Drs Rajendram and Kale1 for their interest in our study. They highlight several interesting points which we would like to address.

First is regarding the relevance of manikin studies to clinical practice. The main advantage of a manikin study is that conditions can be standardised allowing new equipment to be compared in an environment that does not compromise patient safety. Standardised conditions are, by definition, not possible in normal clinical trials and this may make it less straightforward to answer specific physical questions. The question we started with related to the fact that the C-MAC D-blade (Karl Storz, Tuttlingen, Germany) had been introduced into clinical practice without a specific introducer. This was noticeably different from certain other available devices, in particular the GlideScope (Verathon Inc., Bothwell, Washington, USA). When we asked the manufacturing company why this was the case, we were told it was not generally necessary but if a clinician did choose to use one, it probably did not matter what was used. We thought this advice was not well thought out and the main reason for starting our study was to determine whether or not it did matter. In our manikin study, each clinician intubated with six different introducer strategies in both a simulated normal and difficult airway.2 This type of direct comparison would be difficult to achieve safely in a clinical study because, as we observed, anaesthetists did use stylets differently from one another and in addition this number of airway manoeuvres per patient would be difficult to justify from an ethical standpoint.

Second, we do not consider that ‘service evaluation studies’ of the type described by Rajendram and Kale1 can be regarded as ‘good evidence’. There are many confounding factors when comparing devices in the way described. Indeed, the use of airway equipment as suggested by Rajendram and Kale1 may be dependent on clinicians’ personal preference and just because a device is used more often does not necessarily correspond with efficacy; it may, for example, just be more easily available in the department concerned. We agree that well designed randomised clinical trials by suitably qualified institutions should be the basis for choosing which airway equipment to purchase, in keeping with the Airway Device Evaluation Project Team guidance.3 In fact, our manikin study has been used as the foundation for a currently ongoing clinical trial.

Finally, we were interested to discover that Karl Storz (Tuttlingen, Germany) are now in the process of considering the introduction of a stylet for use with their C-MAC D-blade. This could imply that our study may have not only come to the attention of one leading manufacturer of airway devices but perhaps even influenced this decision.

Acknowledgements relating to this article

Assistance with the reply: none.

Financial support and sponsorship: there was no financial support. The C-MAC videolaryngoscope was loaned by Karl Storz, Tuttlingen, Germany, for the duration of the study.

Conflicts of interest: none.


1. Rajendram R, Kale V. The use of advanced airway management devices in clinical practice. Eur J Anaesthesiol 2016; 33:469–470.
2. Batuwitage B, McDonald A, Nishikawa K, et al. Comparison between bougies and stylets for simulated tracheal intubation with the C-MAC D-blade videolaryngoscope. Eur J Anaesthesiol 2015; 32:400–405.
3. Pandit JJ, Popat MT, Cook TM, et al. The DAS ‘ADEPT’ guidance on selecting airway devices: the basis of a strategy for equipment evaluation. Anaesthesia 2011; 66:726–737.
© 2016 European Society of Anaesthesiology