We thank Drs Cui, Xue and Wang for their interest in our study ‘Tracheal intubation with a flexible fibreoptic scope or the McGrath videolaryngoscope in simulated difficult airway scenarios’.1 In their letter, Drs Cui, Xue and Wang suggest further discussion of five aspects of our study.2 We welcome these discussions and will in the following address each of them in turn.
First aspect is that Drs Cui, Xue and Wang raise concern that our study will misdirect clinicians and discourage them from learning awake fibreoptic intubation in patients with known altered upper airway anatomy.
For this, we would first like to point out that in our study, we compared two different methods of securing a difficult airway in relation to unanticipated difficult airway management. Therefore, the scenarios with pharyngeal obstruction, pharyngeal obstruction and cervical rigidity, and tongue oedema were scheduled as patients undergoing simulated general anaesthesia. All situations could in fact arise after the induction of general anaesthesia in patients who were evaluated preoperatively as having a normal airway.
Second, we question the statement raised regarding videolaryngoscope intubation failure in patients with altered head and neck anatomy. Unfortunately, the subgroup analysis referred to in the study by Aziz et al.3 is based on a heterogeneous patient material that does not allow strong conclusions to be drawn. Interestingly, Glidescope videolaryngoscope intubation failure was followed by the majority of the patients (47%) being successfully direct laryngoscopic intubated compared with 32% of the patients who were successfully fibreoptic intubated on the second attempt. The McGrath videolaryngoscope requires a mouth opening of no more than 15 mm similar to a Berman airway. Obviously, large pharyngeal and laryngeal masses would challenge the anaesthesiologist using both a McGrath videolaryngoscope and a fibreoptic scope. The view through the fibrescope is more obscured by blood in the airway compared with the videolaryngoscope.
Third, we want to clarify that we do not advocate abandoning fibreoptic intubation. However, this procedure is not fail proof and has also been associated with brain damage and death when used for awake intubation.4 Our study once again emphasises that we do not have an intubation technique that will fit all patients and also stresses the importance of anaesthesiologists mastering several techniques.
The second aspect is that in the letter, the question is raised of whether videoscopic intubation is really easier to master than fibreoptic intubation. This is a valid question, and we do not claim to know the full truth. Our study investigated anaesthesia residents with a mean of 29 months of anaesthesia experience. The participants found the videolaryngoscope easier to use than the Flexible Fiberoptic Endoscope in two out of three scenarios, and found the two devices to be equally difficult in the third scenario. Furthermore, the results of the survey referred to in the letter, regarding self-reported airway training, are subjected to huge bias with a response rate of only 60%; furthermore, not all questions were answered by all respondents.5
The third aspect is that Drs Cui, Xue and Wang question the relevance of comparing the performance of FFE and videolaryngoscope using the Cormack and Lehane classification system, usually used in conjunction with direct Macintosh laryngoscopy.
There is no doubt that correct positioning and alignment of the videolaryngoscope remains crucial for intubation success. Thus, in our study, we used the Cormack and Lehane classification solely for quantifying the residents[Combining Acute Accent] view of the glottic structures, not as a surrogate measure of ease of intubation. To our knowledge, no other validated system is available for this purpose.
The fourth aspect is that in our study, we used ‘dental clicks’ on the manikin as the only available, objective surrogate measure of dental trauma. We do agree with the statement that manikin studies have inherent limitations, namely that the anatomy of manikins is not directly transferable to patients, with the implication that the results must be interpreted cautiously. With this in mind, we welcome future clinical studies investigating suitable techniques for difficult airway management. However, we respectfully disagree with the authors that dental damage is impossible during the insertion and placement of the Berman airway. We are experiencing an increasing geriatric population requiring anaesthesia for a variety of surgical procedures, wherein some patients present themselves with fragile teeth, which are more or less easily damaged – even during the insertion of oral airways.
The fifth and final aspect is that, in the present study, we compared McGrath videolaryngoscope intubation with fibreoptic intubation in simulated anaesthetised patients, in contrast to our other study in which both techniques were used for awake intubation in patients with respiration preserved.6
We once again thank Drs Cui, Xue and Wang for their interest in our study, and we welcome any further questions or comments that may arise from this discussion.
Acknowledgements related to this article
Assistance with the letter: none.
Financial support and sponsorship: none.
Conflicts of interest: none.
1. Jepsen CH, Gätke MR, Thøgersen B, et al. Tracheal intubation with a flexible fibreoptic scope or the McGrath videolaryngoscope in simulated difficult airway scenarios. Eur J Anaesthesiol
2. Cui X-L, Xue F-S, Wang S-Y. Performance of videolaryngoscope and flexible fibreoptic endoscope in simulating difficult airways. Eur J Anaesthesiol
3. Aziz MF, Healy D, Kheterpal S, et al. Routine clinical practice effectiveness of the Glidescope in difficult airway management: an analysis of 2004 Glidescope intubations, complications, and failures from two institutions. Anesthesiology
4. Peterson GN, Domino KB, Caplan RA, et al. Management of the difficult airway: a closed claims analysis. Anesthesiology
5. Pott LM, Randel GI, Straker T, et al. A survey of airway training among U.S. and Canadian anesthesiology residency programs. J Clin Anesth
6. Rosenstock CV, Thøgersen B, Afshari A, et al. Awake fiberoptic or awake video laryngoscopic tracheal intubation in patients with anticipated difficult airway management: a randomized clinical trial. Anesthesiology