Straight blades improve visualization of the larynx while curved blades increase ease of intubation: a comparison of the Macintosh, Miller, McCoy, Belscope and Lee-Fiberview blades

  • Jose J. ArinoEmail author
  • Jose M. Velasco
  • Carmen Gasco
  • Francisco Lopez-Timoneda
Cardiothoracic Anesthesia, Respiration and Airway



To compare the Macintosh (M), McCoy (MC), Miller (MIL), Belscope (BP) and Lee-Fiberview (LF) laryngoscopes with respect to the grade of laryngeal visualization and the difficulty of intubation.


We included 500 patients scheduled to undergo elective surgery and who required tracheal intubation. Patients were randomly assigned to five groups of 100 patients each. Anesthesia was induced intravenously using 1–3 mg·kg−1 of propofol, fentanyl 1.5 μg·kg−1 and atracurium 0.5 mg·kg−1 or suxamethonium I mg·kg−1. The laryngeal view was classified according to Cormack and Lehane. The degree of difficulty with intubation was rated as: Grade I, intubation easy; Grade 2, intubation requiring an increased anterior lifting force and assistance to pull the right corner of the mouth upwards to increase space; Grade 3, intubation requiring multiple attempts and a curved stylet; Grade 4, failure to intubate with the assigned laryngoscope. Data were examined using analysis of variance, Χ2 or Fisher test, Student’s t test and odds ratio.P < 0.05 was considered statistically significant.


Laryngoscopic views obtained with the BP and MIL laryngoscopes were similar, and better than with the other types of laryngoscopes (P < 0.001). The levering tip of the MC blade (P = 0.02) and the fibreoptic device of the LF (P < 0.001) significantly improved the laryngoscopic view. Regarding the degree of difficulty with intubation, the best results were obtained with the MC and M blades (P < 0.001).


Laryngoscopy was better with straight blades but curved blades provided better intubating conditions.


Tracheal Intubation Difficult Intubation Difficult Tracheal Intubation Difficult Laryngoscopy Laryngoscope Blade 
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Les lames droites améliorent la, visualisation du larynx tandis que les lames courbes facilitent l’intubation: une comparaison des lames Macintosh, Miller, McCoy, Belscope et Lee-Fiberview



Comparer les laryngoscopes Macintosh (M), McCoy (MC), Miller (MIL), Belscope (BP) et Lee-Fiberview (LF) quant au degré de visualisation du larynx et à la difficulté d’intubation.


Létude a porté sur 500 patients devant subir une intervention chirurgicale réglée nécessitant une intubation endotrachéale. Les patients ont été répartis en cinq groupes de 100 patients chacun. Lanesthésie a été induite par l’administration intraveineuse de 1–3 mg·kg−1 de propofol, 1,5 μg·kg−1 de fentanyl et 0,5 mg·kg−1 d’atracurium ou I mg·kg−1 de suxaméthonium. La visualisation du larynx a été cotée selon Cormack et Lehane. Le degré de difficulté d’intubation a été noté comme suit: Classe I, intubation facile; Classe 2, intubation nécessitant de soulever l’appareil vers l’avant avec une force croissante et une assistance pour pousser le coin droit de la bouche vers le haut pour accentuer l’ouverture; Classe 3, intubation nécessitant plus d’un essai et un stylet courbe; Classe 4, échec de l’intubation avec le laryngoscope testé. Les données ont été étudiées avec une analyse de variance, le test du Χ2 ou le test de Fisher, le test de Student et le risque relatif. P < 0,05 a été considéré significatif.


La visualisation laryngoscopique a été similaire avec le BP et le MIL, et meilleure qu’avec les autres appareils (P < 0,001). La pointe levier de la lame MC (P = 0,02) et la composante fibroscopique du LF (P < 0,001) ont significativement amélioré la visualisation du larynx. Relativement au degré de difficulté d’intubation, les meilleurs résultats ont été obtenus avec les lames MC et M (P < 0,001).


La laryngoscopie a été meilleure avec les lames droites, mais les lames courbes ont facilité les conditions d’intubation.


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© Canadian Anesthesiologists 2003

Authors and Affiliations

  • Jose J. Arino
    • 1
    Email author
  • Jose M. Velasco
    • 1
  • Carmen Gasco
    • 1
  • Francisco Lopez-Timoneda
    • 1
  1. 1.Department of AnesthesiaHospital Clinico San CarlosMadridSpain

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