title: Comparison of direct and video-assisted views of the larynx during routine intubation.
abstract: OBJECTIVE
  To compare the direct and indirect (video monitor) views of the glottic opening using a new Macintosh blade that is modified to provide a video image of airway structures during laryngoscopy.
  
  
  METHODS
  Prospective multicenter trial.
  
  
  METHODS
  11 university-affiliated hospitals.
  
  
  METHODS
  867 adults undergoing elective surgery requiring general anesthesia and tracheal intubation.
  
  
  METHODS
  Patients received general anesthesia and were paralyzed. Direct laryngoscopy was supervised by one of the investigators at each institution. The best possible view was obtained with a Macintosh video laryngoscope during direct vision using standard techniques such as external laryngeal manipulation and backward, upward, and rightward pressure, if necessary. The laryngoscopist then looked at the video monitor and performed any necessary maneuvers to obtain the best view on the video monitor. Thus, 2 assessments were made during the same laryngoscopy (direct naked-eye view vs video monitor view). Tracheal intubation was then performed using the monitor view. Glottic views were rated according to the Cormack-Lehane scoring system, as modified by Yentis and Lee. A questionnaire was completed for each patient.
  
  
  RESULTS
  Data from 865 patients were suitable for analysis. Visualization was considered easy (Cormack-Lehane score<3) in 737 patients and difficult (Cormack-Lehane score=3 or 4) in 21 for both direct and video-assisted views. In 7 patients, the view was considered easy during direct visualization yet difficult on the video monitor view. On the other hand, the view was considered difficult in 100 patients during direct visualization yet easy on the video monitor view (P<0.001).
  
  
  CONCLUSIONS
  Video-assisted laryngoscopy provides an improved view of the larynx, as compared with direct visualization. This technique may be useful for cases of difficult intubation and reintubation as well as for teaching laryngoscopy and intubation.
authors.affiliation: Department of Anesthesiology, UCLA and Cedars-Sinai Medical Center, Los Angeles, CA 90095, USA, and Department of Anesthesiology, Cantonal Hospital, St Gallen, Switzerland.
authors.forename: Marshal B
authors.initials: MB
authors.lastname: Kaplan
authors.forename: Carin A
authors.initials: CA
authors.lastname: Hagberg
authors.forename: Denham S
authors.initials: DS
authors.lastname: Ward
authors.forename: Ansgar
authors.initials: A
authors.lastname: Brambrink
authors.forename: Ashwani K
authors.initials: AK
authors.lastname: Chhibber
authors.forename: Thomas
authors.initials: T
authors.lastname: Heidegger
authors.forename: Leonardo
authors.initials: L
authors.lastname: Lozada
authors.forename: Andranik
authors.initials: A
authors.lastname: Ovassapian
authors.forename: David
authors.initials: D
authors.lastname: Parsons
authors.forename: James
authors.initials: J
authors.lastname: Ramsay
authors.forename: Wolfram
authors.initials: W
authors.lastname: Wilhelm
authors.forename: Bernhard
authors.initials: B
authors.lastname: Zwissler
authors.forename: Haus J
authors.initials: HJ
authors.lastname: Gerig
authors.forename: Christian
authors.initials: C
authors.lastname: Hofstetter
authors.forename: Suzanne
authors.initials: S
authors.lastname: Karan
authors.forename: Nevin
authors.initials: N
authors.lastname: Kreisler
authors.forename: Robert M
authors.initials: RM
authors.lastname: Pousman
authors.forename: Andreas
authors.initials: A
authors.lastname: Thierbach
authors.forename: Marc
authors.initials: M
authors.lastname: Wrobel
authors.forename: George
authors.initials: G
authors.lastname: Berci
mesh_terms: D000328:Adult; D000768:Anesthesia, General; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D020704:Laryngoscopes / Q000706:statistics & numerical data*; D007828:Laryngoscopy / Q000379:methods*; D007830:Larynx; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014741:Video Recording