Fibreoptic assessment of laryngeal aperture in patients with difficult laryngoscopy

  • Ichiro Takenaka
  • Kazuyoshi Aoyama
  • Tatsuo Kadoya
  • Takeyoshi Sata
  • Akio Shigematsu
Reports of Investigation



To determine the relationship between the area of the laryngeal aperture (LA) seen fibreoptically during laryngoscopy and the difficulty of tracheal intubation in patients with difficult laryngoscopy


In 587 adult patients after induction of general anesthesia and muscle relaxation, the best laryngoscopic view of the larynx using a Macintosh 3 blade was classified according to Cormack. When the LA could not be seen, with laryngoscope blade in place, the LA view provided by a fibreoptic bronchoscope (FOB)-camera passed nasally was photographed. Then, the laryngoscopist attempted to intubate the trachea using the Macintosh blade. Tracheal intubation requiring more than three attempts was defined as difficult. After the third attempt, the trachea was intubated orally aided by FOB. The LA view after jaw thrust during FOB-aided intubation was photographed.


Laryngoscopy was difficult in 17 of 587 patients. In four, intubation was difficult. In the remaining 13 patients the trachea was easy to intubate. The LA area obtained by the FOB in the difficult group (median, 0.19; intra-quartile range, 0.14 to 0.39 cm2) was smaller than that in the easy group (2.43; 1.84 to 2.93 cm2)(P =0.003). In contrast, the LA area provided by jaw thrust during the FOB-aided intubation in the difficult group (2.28; 1.99 to 2.73 cm2) was similar to that during laryngoscopy in the easy group.


Inability of the laryngoscope to provide an adequate LA view is one cause of difficult intubation with the Macintosh laryngoscope in patients with difficult laryngoscopy.


Tracheal Intubation Difficult Intubation Macintosh Laryngoscope Difficult Tracheal Intubation Difficult Laryngoscopy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



Déterminer la relation entre la zone d’ouverture laryngienne (OL) décelée pendant la laryngoscopie fibroscopique et la difficulté d’intubation endotrachéale chez des patients dont la laryngoscopie est difficile.


Après l’induction de l’anesthésie générale et la curarisation chez 587 adultes, la meilleure vision laryngoscopique du larynx obtenue avec une lame de Macintosh 3 a été classée selon Cormack. Quand on ne pouvait visualiser l’OL à partir de la lame du laryngoscope en place, on a photographié l’OL obtenue avec une caméra de fibroscope bronchique (FOB) introduite par voie nasale. Ensuite, on a tenté l’intubation endotrachéale avec la lame Macintosh. L’intubation qui nécessitait plus de trois essais était jugée difficile. Après le troisième essai, l’intubation était réalisée par voie orale avec le FOB. On a photographié l’OL après la subluxation de la mâchoire pendant l’intubation facilitée par le FOB.


La laryngoscopie a été difficile chez 17 patients et l’intubation a été difficile chez 4 d’entre eux. La zone d’OL obtenue à l’aide du FOB dans le groupe à intubation difficile (médiane, 0,19; intervalle intra-quartile, 0,14 à 0,39 cm2) était plus petite que celle du groupe à intubation facile (2,43; 1,84 à 2,93 cm2; P = 0,003). Par ailleurs, l’OL obtenue par la subluxation de la mâchoire, pendant l’intubation facilitée par le FOB dans le groupe difficile (2,28; 1,99 à 2,73 cm2), était similaire à celle qu’on a obtenue pendant la laryngoscopie dans le groupe facile.


Limpossibilité du laryngoscope de fournir une vision valable de l’OL est l’une des causes de l’intubation difficile avec le laryngoscope Macintosh chez des patients dont la laryngoscopie est difficile.


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Copyright information

© Canadian Anesthesiologists 1999

Authors and Affiliations

  • Ichiro Takenaka
    • 1
  • Kazuyoshi Aoyama
    • 1
  • Tatsuo Kadoya
    • 1
  • Takeyoshi Sata
    • 1
  • Akio Shigematsu
    • 1
  1. 1.Department of AnesthesiologySchool of Medicine University of Occupational and Environmental HealthYahatanishi-ku KitakyushuJapan

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