Alternative techniques for tracheal intubation

Alternative rigid blade intubation devices have become available in recent years including Glidescope, Airtraq and Bonfils laryngoscopes. The Macintosh curved blade works by displacing the tongue to one side and also into the submandibular space. This allows the device to get into the valleculum and hence lift the hyoid and epiglottis forward to reveal the laryngeal inlet. Under less favourable intubating conditions, the tongue tends to be compressed disproportionately, the valleculum is not accessed and the blade tip cannot be drawn forward. The retro-molar Bonfils avoids this problem by starting from a lower position in the mouth and approaching the larynx below and alongside the tongue. Bonfils also serves as a rigid stylet inside the tracheal tube which also implies minimal tongue displacement. By comparison, the Airtraq does not need to compress the tongue to the same degree as Macintosh and usually sits on the posterior pharyngeal wall, maintaining the view with minimal effort. It houses the tracheal tube a channel from which it is delivered into the field of view. While the optical systems have tended to improve viewing conditions at the laryngeal inlet this has not necessarily resulted in easier intubation conditions, shorter intubation times or improved success rates. Part of the problem has been that they tend to limit the field of view compared with the all round view down to the larynx afforded by Macintosh under ideal conditions.