Use of the Pentax-AWS in 293 patients with difficult airways.

Background: Several case reports have shown that the Pentax-AWS® (Hoya Corporation, Tokyo, Japan), a new video laryngoscope, is useful in patients with difficult airways. Methods: We assessed the effectiveness of the Pentax-AWS® in two groups. Group 1 included 270 patients in whom direct laryngoscopy using a Macintosh laryngoscope had been difficult. Group 2 included 23 patients with predicted difficult intubation and difficult mask ventilation without previous use of the Macintosh laryngoscope. Results: In group 1, the view of the glottis with the Macintosh laryngoscope was Cormack and Lehane grade 2 in 14 patients, grade 3 in 208 patients, and grade 4 in 48 patients. In 256 patients in whom the grade was 3 or 4 with the Macintosh laryngoscope, the view with the Pentax-AWS® was either grade 1 or 2 in 255 patients (99.6%; 95% confidence intervals 97.8-100%). Tracheal intubation was successful with the Pentax-AWS® in 268 of 270 patients (99.3%; 95% confidence interval 97.4-100%), and it failed (after two attempts) in two patients. In group 2, tracheal intubation was successful in 22 of 23 patients, and it failed in one patient. The reasons for failed intubation using the Pentax-AWS® were failure to position the blade toward the glottic side of the epiglottis, inability to maneuver the endotracheal tube away from the arytenoids and into the trachea, and bleeding and swelling of the oropharynx. Conclusion: The success rate of tracheal intubation using the Pentax-AWS® was high in patients with difficult laryngoscopy with a Macintosh laryngoscope and in patients with predicted difficult intubation.