Comparison of direct and video-assisted views of the larynx during routine intubation.
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.
Kaplan
Marshal B
MB
Department of Anesthesiology, UCLA and Cedars-Sinai Medical Center, Los Angeles, CA 90095, USA, and Department of Anesthesiology, Cantonal Hospital, St Gallen, Switzerland.
Hagberg
Carin A
CA
Ward
Denham S
DS
Brambrink
Ansgar
A
Chhibber
Ashwani K
AK
Heidegger
Thomas
T
Lozada
Leonardo
L
Ovassapian
Andranik
A
Parsons
David
D
Ramsay
James
J
Wilhelm
Wolfram
W
Zwissler
Bernhard
B
Gerig
Haus J
HJ
Hofstetter
Christian
C
Karan
Suzanne
S
Kreisler
Nevin
N
Pousman
Robert M
RM
Thierbach
Andreas
A
Wrobel
Marc
M
Berci
George
G
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