Marketing New Video Laryngoscopes without Clinical Evaluation
Ernst Zadrobilek, MD1
of Anesthesia and Intensive Care, Chairman of the Austrian Working
Group for Airway Management,
Address correspondence and comments to
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
Available from URL:
Date accessed: month day, year.
updated: November 24, 2010.
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.
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
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
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.
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.
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.
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.
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.