Video laryngoscope

A video laryngoscope is a scope designed to visualize the larynx using video technology.

The video laryngoscope is a device which uses a video camera mounted on a scope used to provide access and view to the larynx for intubation, diagnosis, removal of foreign bodies and passage of endotracheal tubes via a nasal or oral route. The conventional direct laryngoscope (DL) uses a line of sight provided by a rigid scope with a light on the blade or intra-oral portion which requires a direct view of the target larynx. The DL view is clearly seen in 80-90 % of attempts to view. Failed direct laryngoscopy is a term Dr Cooper chose to focus on the inadequate visualization that may lead to failed intubation(1). The failure to provide a view led to a generation of indirect viewing laryngoscopes relying on fiberoptic imaging to improve the results. These devices were an improvement but have limitations commonly associated with unheated viewers such as fogging of the lens area.

The invention of the Glidescope Video laryngoscope in 2000 by Dr John Pacey, a Vancouver surgeon, introduced the concept of a CCD or CMOS camera placed at a point on the blade ,back from the tip, designed to provide perspective of the field in front of the camera. The 60 degree angle of the blade provided an ability to "see around the corner" behind the tongue to an anteriorly placed larynx. This popular device increases the reliability of the laryngoscope to 99%. (2) The lens on this device is heated to prevent fog accretion on the lens area.

There are now a number of video laryngoscopes available and these include the McGrath laryngoscope, The Storz C-Mac,Pentax AWS and the Berci DCI. These laryngoscopes use a variety of form factors such as Monitor on the handle and or channels to attempt to guide the endotracheal tube into the trachea. The superior performance of Video Laryngoscopes in airway management where neck injury is possible (3) has raised the question of whether these scopes should supersede direct laryngoscopy in day to day airway management.

References

1.Cooper, Richard The use of a new video laryngoscope (Glidescope(R) in the management of difficult airway, Canadian Journal of Anesthesia 2003;50:6 6111-613

2.Cooper, Richard,et al. Early clinical experience with a new videolaryngoscope (Glidescope (R)) in 728 patients. Canadian Journal of Anesthesia 2005; 52:2: 191-198.

3.Agro F, Barzoi G, Montecchia F, Tracheal intubations using a Macintosh laryngoscope or a Glidescope(R)in 15 patients with cervical spine immobilization. British Journal of Anesthesia, 2003;90: 705-706.letter.