title: Evaluation of the Pentax-AWS(®) and the Macintosh laryngoscope in difficult intubation: a manikin study.
abstract: BACKGROUND
  The Pentax-AWS (AWS(®)), a new video laryngoscope, has been shown to be useful in cases of difficult intubation. We hypothesized that the AWS(®) would be more useful in the settings of a narrow upper airway than the Macintosh laryngoscope. We compared each device in simulated scenarios of representative difficulty of tracheal intubation using a manikin. The primary endpoint was the rate of successful intubation.
  
  
  METHODS
  With each device, 23 anesthesiologists performed tracheal intubation in a SimMan(®) manikin in the following scenarios: (1) normal airway, (2) tongue edema, (3) cervical spine rigidity, (4) pharyngeal obstruction, (5) jaw trismus, (6) tongue edema with pharyngeal obstruction. The intubation time and success rate were measured. Each participant was asked to rate the difficulty of intubation (1=very easy; 5=very difficult).
  
  
  RESULTS
  In the scenarios of tongue edema and tongue edema with pharyngeal obstruction, the AWS(®) yielded a higher success rate (100% vs. 34.8%; P<0.001, 65.2% vs. 21.7%; P=0.006), a shorter intubation time [14.6 (7.0) vs. 33.4 (13.0) s; P<0.001, 24.5 (12.0) vs. 37.6 (11.9); P=0.047; mean (standard deviation)], and a lower difficulty score [2 (1-4) vs. 5 (1-5); P<0.001, 4 (2-5) vs. 5 (3-5); P<0.001; median (range)], compared with the Macintosh laryngoscope.
  
  
  CONCLUSIONS
  The AWS(®) has an advantage over the Macintosh laryngoscope in simulated tongue edema and tongue edema with pharyngeal obstruction. Further studies in a clinical setting are necessary to confirm these findings.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Yokohama City University School of Medicine, Japan. karix@cl.cilas.net
authors.forename: T
authors.initials: T
authors.lastname: Kariya
authors.forename: G
authors.initials: G
authors.lastname: Inagawa
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: J
authors.initials: J
authors.lastname: Fujimoto
authors.forename: Y
authors.initials: Y
authors.lastname: Aoi
authors.forename: S
authors.initials: S
authors.lastname: Morita
authors.forename: T
authors.initials: T
authors.lastname: Goto
mesh_terms: D000402:Airway Obstruction; D002983:Clinical Competence; D004487:Edema / Q000150:complications; D023381:Endpoint Determination; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation*; D020704:Laryngoscopes; D008348:Manikins; D010614:Pharynx / Q000473:pathology; D018401:Sample Size; D013122:Spinal Diseases / Q000473:pathology; D014059:Tongue / Q000473:pathology; D014313:Trismus / Q000473:pathology