Comparison of direct and video-assisted views of the larynx during routine intubation

Marshal B. Kaplan, Carin A. Hagberg, Denham S. Ward, Ansgar Brambrink, Ashwani K. Chhibber, Thomas Heidegger, Leonardo Lozada, Andranik Ovassapian, David Parsons, James Ramsay, Wolfram Wilhelm, Bernhard Zwissler, Haus J. Gerig, Christian Hofstetter, Suzanne Karan, Nevin Kreisler, Robert M. Pousman, Andreas Thierbach, Marc Wrobel, George Berci

Research output: Contribution to journalArticlepeer-review

178 Scopus citations


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. Design: Prospective multicenter trial. Setting: 11 university-affiliated hospitals. Patients: 867 adults undergoing elective surgery requiring general anesthesia and tracheal intubation. Interventions: 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. Measurements and Main 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.

Original languageEnglish (US)
Pages (from-to)357-362
Number of pages6
JournalJournal of Clinical Anesthesia
Issue number5
StatePublished - Aug 2006
Externally publishedYes


  • Laryngoscopy
  • Macintosh video laryngoscope

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine


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