Abstract
Purpose
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.
Methods
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.
Results
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).
Conclusion
Laryngoscopy was better with straight blades but curved blades provided better intubating conditions.
Résumé
Objectif
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.
Méthode
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.
Résultats
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).
Conclusion
La laryngoscopie a été meilleure avec les lames droites, mais les lames courbes ont facilité les conditions d’intubation.
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References
McCoy EP, Mirakhur RK. The levering laryngoscope. Anaesthesia 1993; 48: 516–9.
Bellhouse CP. An angulated laryngoscope for routine and difficult tracheal intubation. Anesthesiology 1988; 69: 126–9.
Perucho A, Ariño JJ, Santé L, Yuste J, Timonean FL. Recognition of the difficult airway. An integrated test. Br J Anaesth 1997; 78: 11 (abstract).
Mallampati SR. Clinical signs to predict difficult tracheal intubation (hypothesis) (Letter). Can Anaesth Soc J 1983; 30: 316–7.
Bellhouse CP, Doré C. Criteria for estimating likelihood of difficulty of endotracheal intubation with the Macintosh laryngoscope. Anaesth Intensive Care 1988; 16: 329–37.
Benumof JL. Management of the difficult adult airway. With special emphasis on awake tracheal intubation. Anesthesiology 1991; 75: 1087–110.
Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984; 39: 1105–11.
Yardeni IZ, Gefen A, Smolyarenko V, Zeidel A, Beilin B. Design evaluation of commonly used rigid and levering laryngoscope blades. Acta Anaesthesiol Scand 2002; 46: 1003–9.
Marks RRD, Hancock R, Charters P. An analysis of laryngoscope blade shape and design: new criteria for laryngoscope evaluation. Can J Anaesth 1993; 40: 262–70.
Relle A. Laryngoscope design (Letter). Can J Anaesth 1994; 41: 162–3.
Benumof JL. Difficult laryngoscopy: obtaining the best view (Editorial). Can J Anaesth 1994; 41: 361–5.
Chisholm DG, Calder I. Experience with the McCoy laryngoscope in difficult laryngoscopy. Anaesthesia 1997; 52: 906–8.
Tuckey JP, Cook TM, Render CA. An evaluation of the levering laryngoscope. Anaesthesia 1996; 51: 71–3.
Tevitan RM, Ochroch EA. Explaining the variable effect on laryngeal view obtained with the McCoy laryngoscope (Letter). Anaesthesia 1999; 54: 599–620.
Aoyama K, Nagaoka E, Takenaka I, Kadoya T. The McCoy laryngoscope expands the laryngeal aperture in patients with difficult intubation (Letter). Anesthesiology 2000; 92: 1855–6.
Bito H, Nishiyama T, Higashizawa T, Sakai T, Konishi A. Determination of the distance between the upper incisors and the laryngoscope blade during laryngoscopy: comparisons of the McCoy, the Macintosh, the Miller, and the Belscope blades. Masui 1998; 47: 1257–61.
Watanabe S, Suga A, Asakura N, et al. Determination of the distance between the laryngoscope blade and the upper incisors during direct laryngoscopy: comparisons of a curved, an angulated straight, and the two straight blades. Anesth Analg 1994; 79: 638–41.
Sakai T, Konishi A, Nishiyama T, Higashizawa T, Bito H. A comparison of the grade of laryngeal visualisation-the McCoy compared with the Macintosh and the Miller blade in adults. Masui 1998; 47: 998–1001.
Taguchi N, Watanabe S, Kumagai M, Takeshima R, Asakura N. Radiographic documentation of increased visibility of the larynx with a Belscope laryngoscope blade. Anesthesiology 1994; 81: 773–5.
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Arino, J.J., Velasco, J.M., Gasco, C. et al. 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. Can J Anesth 50, 501–506 (2003). https://doi.org/10.1007/BF03021064
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DOI: https://doi.org/10.1007/BF03021064