Internet Journal of Airway Management


Volume 6 (January 2010 to December 2011)


Marketing New Video Laryngoscopes without Clinical Evaluation



Ernst Zadrobilek, MD1  


1Associate Professor of Anesthesia and Intensive Care, Chairman of the Austrian Working Group for Airway Management, Vienna, Austria.


Address correspondence and comments to Ernst Zadrobilek.


Published: November 8, 2010.



The correct citation of this editorial view is:

Zadrobilek E. Marketing new video laryngoscopes without clinical evaluation. Internet Journal of Airway Management 6, 2010-2011.
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Date accessed: month day, year.


Last updated: November 24, 2010.


The laryngeal mask airway (LMA) has significantly changed anesthetic practice. There is now an increasing market particularly for disposable LMA devices. They were usually marketed without clinical evaluation and there are important design differences between them and compared with original LMAs (1). For marketing new medical devices in Europe, only a CE (Conformite Europeene) mark, assessing production quality controls and manufacturing standards, is necessary; the evidence of clinical performance and patient safety is not required. During the postmarketing period, some time may elapse until clinical studies are published in peer-reviewed journals. Furthermore, new devices are often redesigned after the initial release to the market, which may lead to considerable confusion.


The same marketing policy was evident with the introduction of rigid video laryngoscopes (VLs) into anesthetic practice. Early users of the various models and systems of the GlideScope (Verathon Medical, Bothell, Washington, United States), the McGrath Series 5 (Aircraft Medical, Edinburgh, United Kingdom), and the Pentax Airway Scope (Pentax Life Care Division, Tokyo, Japan) had problems with laryngoscopy and particularly with the advancement of the tracheal tube through the laryngeal aperture into a midtracheal position mainly due to the sparce information on their performance and limitations. The same problems will arise with recently launched VLs such as the King Vision (King Systems, Noblesville, Indiana, United States), the McGrath MAC (Aircraft Medical), the D-BLADE for the Storz C-MAC system (Karl Storz Endoscopy, Tuttlingen, Germany), and the Venner AP Advance (Venner Medical, Singapore).


The Airtraq optical laryngoscope (Prodol Meditec, Vizcaya, Spain) may be used together with a clip-on camera as VL. Tracheal intubation along a tube guide channel is significantly different from free-handed tracheal intubation; the implications of this feature for performance had not been evaluated in a clinical study before release of this laryngoscope to the market. The unfamiliar feature of a tube guide channel  is also provided for the King Vision, the Pentax Airway Scope, and the Venner AP Advance.


In general, the currently available VLs were primarily designed for use in adult patients. The manufacturers of the GlideScope and the Airtraq extended their product line to pediatric and even to infant laryngoscope blades; they are in design merely smaller-sized versions of the original adult blades. The evidence of their at least equal performance for tracheal intubation in these patient populations compared to conventional laryngoscopy (CL) is still lacking.    


The Ambu aScope (Ambu, Ballerup and Olstykke, Denmark), a disposable flexible VL, presumably did not undergo a premarketing evaluation; experienced endoscopists would have critisized the test models because the working channel cannot be used for suctioning which makes this endoscope less suitable for tracheal intubation. Redesigning and reevaluation of this device before marketing might have significantly improved its suitability for anesthetic practice.


New airway devices should undergo mandatory assessment of manufacturing quality and clinical performance before marketing. This is best performed by a staged procedure (1): first a bench evaluation on airway models designed to test function and safety, followed by a rigorous clinical cohort study to determine whether the device is effective and safe, and finally a randomized controlled trial against the current gold standard for the procedure and the patient population for which the new device is expected to be used (for rigid VLs, comparison with CL using a standard Macintosh laryngoscope and successful tracheal intubation, preferably at the first attempt). The clinical evaluations should be ideally performed by independent investigators. Significant modifications necessitate repetition of the initial evaluations. Furthermore, formal methods of postmarketing surveillance and reporting of adverse incidents should be developed and instituted.


Tracheal intubation with VLs in suitable airway models is usually easy to perform. Untoward problems, for example with fogging of the camera or optical system obscuring the view and with inadequate blade designs and configurations for use in patients with anatomic variations can be detected only by clinical studies.


VLs are increasingly promoted by their manufacturers for emergency airway management. Particularly in prehospital settings with low ambient temperatures and/or bright lighting conditions, there may arise severe problems with the image diplayed on the video screen. Without exception, the currently available VLs are not tested in these environments.   




  1. Hagberg CA, Agro FE, Cook TM, Reed AP. New generation supraglottic ventilatory devices. In: Hagberg CA (ed) Benumofs's airway management. Philadelphia, Mosby Elsevier, p 502-531, 2007.

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