Alternative techniques for tracheal intubation

Alternative rigid blade intubation devices available in recent years include the Glidescope, Airtraq and Bonfils laryngoscopes. The Macintosh blade works by displacing the tongue to one side and into the submandibular space while the tip of the device sits in the vallecula lifting the hyoid and so the epiglottis forward to reveal the laryngeal inlet. Under less favourable intubating conditions, the tongue is not accommodated in the submandibular space and tends to be compressed downwards. As a result the vallecula is not accessible and the blade tip is less able to be drawn forward. The retro-molar Bonfils avoids this problem by starting from a posterior position in the mouth and approaching the larynx below and alongside the tongue. The Bonfils also serves as a rigid stylet inside the tracheal tube again producing minimal tongue displacement. Airtraq also compresses the tongue less and usually sits on the posterior pharyngeal wall where it maintains the laryngeal view with a minimum of effort. It houses the tracheal tube in a channel that delivers it into the device's field of view. While better optical systems have tended to improve visualization of the laryngeal inlet, this has not necessarily resulted in easier intubation conditions, shorter intubation times or improved overall success rates. Part of the problem has been that they have limited fields of view compared with the stereoscopic view of tube advancement down to the larynx as afforded by Macintosh.