Abstract
Purpose
Defintions currently used to describe airway difficulties are confusing, inconsistent, and may be misleading. To understand the “extent of the problem” better using three different definitions we examined the corresponding rates of airway difficulty in 3,325 consecutive adult patients who had direct laryngoscopy with tracheal intubation following induction of general anaesthesia.
Methods
Definitions were (i) poor view at laryngoscopy (GRADE 3–4) documented on modified diagrams of Cormack and Lehane; (ii) ≥3 laryngoscopy attempts; and (iii) failure of direct laryngoscopy. The incidences of airway difficulty attributable to each definition were compared.
Results
For the three definitions rates varied, 10.1% for poor view, 1.9% ≥3 laryngoscopies, and failure 0.1%. For patients with a GRADE 3–4 view, 15.8% required ≥3 laryngoscopies, but for those with ≥3 laryngoscopies, 84.1% had GRADE 3–4 view. All patients with failed laryngoscopy had ≥3 laryngoscopies and a GRADE 4 view.
Conclusion
This wide variation in defining the “extent of the problem” emphasizes the need for agreement of definitions and improved methods to document airway difficulties.
Résumé
Objectif
Les définitions en usage actuellement pour caractériser les problèmes rencontrés au niveau des voies aériennes créent de la confusion, sont inconstantes et souvent trompeuses. Pour mieux comprendre l’importance du problème, nous avons étudié, à l’aide de trois définitions, la proportion correpondante de difficultés au niveau des voies respiratoires de 3325 adultes consécutifs qui subissaient une laryngoscopie directe avec intubation de la trachée sous anesthésie générale.
Méhodes
Les définitions choisies étaient: i) la visualisation médiocre à la laryngoscopie (grades 3 et 4) documentée sur des diagrammes modifiés de Cormack et Lehane; ii) trois tentatives de laryngoscopie ou plus; et iii) l’échec de la laryngoscopie directe. L’incidence des difficultés causées par les voies aériennes correspondant à chacune de ces définitions a été comparée.
Résultats
Les taux ont varié selon la définition; 10,1% pour ta visualisation médiocre, 1,9% pour trois laryngoscopies et plus, et 0,1 pour l’échec de la laryngoscopie. Des patients dont la visuasalisation était de grade 3–4,15.8% ont eu besoin d’au moins trois laryngoscopies mais pour ceux qui ont eu besoin d’au moins trois laryngoscopie, 84,1% avaient une visualisation de grade 3–4. Dans tous les cas d’échec, on a réalisé trois laryngoscopies et plus et la visualisation était de grade 4.
Conclusion
La grande variabilité des définitions souligne le besoin d’une concertation sur les définitions et de l’amélioration des méthodes qui servent à documenter les problèmes qu ’on rencontre au niveau des voies aériennes.
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References
Sampsoon G, Young J. Difficult tracheal intubation. Anaesthesia 1987; 42: 87–90.
Norton ML Brown ACD. Evaluating the patient with a difficult airway for anesthesia. Otolaryngol Clin North Am 1990; 23: 771–85.
American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Practice guidelines for management of the difficult airway. Anesthesiology 1993; 78: 597–602.
Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984; 39: 1105–11.
Benumof JL Management of the difficult airway. With special emphasis on awake tracheal intubation. Anesthesiology 1991; 75: 1087–110.
Rose DK, Cohen MM. The airway: problems and predictions in 18,500 patients. Can J Anaesth 1994; 41: 372–83.
Rose DK, Cohen MM, Wigglesworth DF, Yee DA. Development of a computerized database for the study of anaesthesia care. Can J Anaesth 1992; 39: 716–23.
Lewis M, Keramati S, Benumof JL, Berry CC. What is the best way to determine oropharyngeal classification and mandibular space length to predict difficult laryngoscopy? Anesthesiology 1994; 81: 69–75.
Wilson ME, Spiegelhalter JA, Robertson JA, Lesser P. Predicting difficult intubation. Br J Anaesth 1988; 61: 211–6.
Williams KN, Carli F, Cormack RS. Unexpected, difficult laryngoscopy: a prospective survey in routine general surgery. Br J Anaesth 1991; 66: 38–44.
Oates JDL, MacLeod AD, Oates PD, Pearsall FJ, Howie JC, Murray GD. Comparison of two methods for predicting difficult intubation. Br J Anaesth 1991; 66: 305–9.
Rocke DA, Murray WB, Rout CC, Gouws E. Relative risk analysis of factors associated with difficult intubation in obstetric anesthesia. Anesthesiology 1992; 77: 67–73.
Frerk CM. Predicting difficult intubation. Anaesthesia 1991; 46: 1005–8.
Savva D. Prediction of difficult tracheal intubation. Br J Anaesth 1994; 73: 149–53.
Mallampati SR, Gatt SP, Gugino LD, et al. A clinical sign to predict difficult tracheal intubation: a prospective study. Can J Anaesth 1985; 32: 429–34.
Benumof JL. Difficult laryngoscopy: obtaining the best view. Can J Anaesth 1994; 41: 361–5.
Cohen AM, Fleming BG, Wace JR. Grading of direct laryngoscopy. A survey of current practice. Anaesthesia 1994, 49: 522–5.
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Supported by a grant from Physicians’ Services Incorporated Foundation, Ontario. Dr. Cohen is the recipient of a National Health Scholar Award from Health Canada.
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Rose, D.K., Cohen, M.M. The incidence of airway problems depends on the definition used. Can J Anaesth 43, 30–34 (1996). https://doi.org/10.1007/BF03015954
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DOI: https://doi.org/10.1007/BF03015954