LETTERS TO EDITOR
Year : 2020 | Volume
| Issue : 4 | Page : 549-550
The role of the hyper-angulated videolaryngoscope in nasotracheal intubation
Kan Chandradeva1, Divya Harshan2
1 Consultant Anaesthetist, Department of Anaesthesia, Princess Royal University Hospital, King's College Hospital NHS Foundation Trust, London, UK
2 Senior Clinical Fellow in Anaesthesia, Department of Anaesthesia, Princess Royal University Hospital, King's College Hospital NHS Foundation Trust, London, UK
Dr. Kan Chandradeva
Department of Anaesthesia, Princess Royal University Hospital Farnborough, Orpington BR6 8ND
Source of Support: None, Conflict of Interest: None
|Date of Submission||25-Dec-2019|
|Date of Acceptance||29-Dec-2019|
|Date of Web Publication||24-Sep-2020|
|How to cite this article:|
Chandradeva K, Harshan D. The role of the hyper-angulated videolaryngoscope in nasotracheal intubation. Saudi J Anaesth 2020;14:549-50
We have been performing nasotracheal intubations with hyper-angulated videolaryngoscopes (C-MAC® D-Blade videolaryngoscope, Karl Storz, Tuttlingen, Germany and Spectrum® and LoPro Glidescope videolaryngoscope blade, Verathon, Seattle), which provide an excellent nasal intubating condition, and we wish to report our experience.
In our practice, after the induction of anaesthesia, a nasotracheal tube (Portex® Polar Preformed Tracheal Tube) is passed via one of the nostrils, and a laryngoscopy is performed with a hyper-angulated blade (HAB) videolaryngoscope. A good glottic view is displayed on the monitor, and the endotracheal tube can then be advanced into the trachea with ease. By slightly rotating the endotracheal tube, or through external laryngeal manipulation, or if necessary inflating the cuff in the supraglottic space to lift up the tube to reach the glottic opening and deflating before advancing into the glottis and/or with minimal manoeuvring of the blade under the vision of the videolaryngoscope, we could advance the tube via the glottic opening without causing any significant impingement or displacement of the glottic tissue. We selected the HAB as it has been shown to provide a better laryngeal view than the conventional videolaryngoscopes.
There are many benefits of using a HAB for nasotracheal intubations. Most importantly, this approach displays a magnified structure of the glottis on the monitor. Hence, the tube can be advanced into the trachea under vision.
On the other hand, a direct laryngoscopy does not reveal the complete structure of the glottis to the naked eye during the nasotracheal intubation, as during direct laryngoscopy for nasotracheal intubations, the longitudinal axis of the glottis needs to be aligned with the axis of the nasopharynx for the glottis to receive the advancing tube. Hence, in contrast to the orotracheal intubation, during nasotracheal intubation, the glottis needs to be 'dropped' slightly in order to achieve this alignment. At this point, the glottic view, to the naked eye, is further obstructed by the intervening epiglottis. The consequence of this is that the tube can get inadvertently stuck in the glottic structures and cause tissue trauma.
Hazarika et al. conducted a controlled trial and elicited that when compared to direct laryngoscopy, the C-MAC® D-blade emerged as a better tool in managing difficult airways through nasal routes, in terms of the time taken for intubation, the success rate, the number of attempts, ease of intubation, use of accessory manoeuvres and reduction in trauma. Further, patients with high El Ganzouri Risk Index scores, such as 5-7, who would have otherwise required an awake fiber-optic intubation, could be managed easily with a C-MAC® D-Blade. Interestingly, furthermore, we feel that this technique enables the intubating anaesthetist to adopt a convenient posture than employing a challenging one in the form of flexing the thorocolumbar spine while extending the cervical spine to perform a direct laryngoscopic nasal intubation.
We postulate that the design of the HAB and the anatomical nasopharyngeal-laryngeal axis seem to complement each other to optimise the nasotracheal intubating condition. The D-Blade has an inbuilt pronounced angulation of 40° compared to the 18° angulation of conventional C-MAC blades. This enhanced angulation of the D-Blade and the more acute oropharyngeal-laryngeal axis, compared to the nasopharyngeal-laryngeal axis, make the reported orotracheal intubation somewhat difficult, as a tube needs to travel along a highly curved path to enter the glottis. This difficulty appears to be effectively attenuated by virtue of the less acute angulation of nasopharyngeal-laryngeal axis.
Therefore, we believe that the HAB has a significant and important role to play in enhancing the safety and success rate of nasotracheal intubations. Further, we envisage that this technique may have a rescue role to play in cases of failed tracheal intubation via the oral route.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Cavus E, Neumann T, Doerges V, Moeller T, Scharf E, Wagner K, et al
. First clinical evaluation of the C-MAC D-Blade videolaryngoscope during routine and difficult intubation. Anesth Analg 2011;112:382-5.
Hazarika H, Saxena A, Meshram P, Kumar Bhargava A. A randomised controlled trial comparing C Mac D Blade and Macintosh laryngoscope for nasotracheal intubation in patients undergoing surgeries for head and neck cancer. Saudi J Anaesth 2018;12:35-41.
Jain D, Dhankar M, Wig J, Jain A. Comparison of the conventional CMAC and the D-blade CMAC with the direct laryngoscopes in simulated cervical spine injury – A manikin study. Braz J Anesth 2014;64:269-74.
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