Abstract
The purpose of this study was to describe methods, risk factors, and outcomes of airway management in all patients (obstetrics excluded) attended by anaesthetists over 27 months. Preoperatively, anaesthetists recorded patient factors and assessed four airway characteristics. Methods of tracheal intubation and ease of direct laryngoscopy following general anaesthesia (easy, awkward, difficult) were noted. Factors predictive of poor outcome and the value of the preoperative airway examination were determined. For 18,205 patients following a direct laryngoscopy, (GA), tracheal intubation was difficult (> 2 laryngoscopies) in 1.8% and awkward (≤2 laryngoscopies) in 2.5%. This approach was a failure in 0.3%, and surgery was postponed in 0.05%. However, an alternative approach to direct laryngoscopy, (GA) was the first choice in 353 patients. Risk factors for difficult tracheal intubation included male sex, age 40–59 yr and obesity (P≤0.01). For direct laryngoscopy, (GA), airway characteristics predictive of difficult tracheal intubation were decreased mouth opening (relative risk 10.3), shortened thyromental distance (9.7), poor visualization of the hypopharynx (4.5), and limited neck extension (3.2), any two (7.6) and more than two (9.4) (P< 0.01). For 1,856 patients (10.0%) where at least one airway characteristic was abnormal, a direct laryngoscopy, (GA) resulted in 8.3% awkward and 6.0% difficult tracheal intubations. For patients with no abnormal airway characteristics, tracheal intubation was easy in 96.3%. Where tracheal intubation was difficult, 34.3% of patients had one or more abnormal airway characteristics preoperatively. Patients with difficult tracheal intubation had an increased rate of desaturation (< 90%), hypertension (> 200 mmHg) and dental damage on induction of anaesthesia. It is concluded that difficult tracheal intubations occurred infrequently but were associated with increased morbidity. Patient factors and four physical airway characteristics were useful predictors but limited in identifying all problems.
Résumé
Cette étude porte sur la description des méthodes, des facteurs de risque et sur les résultats de la gestion des voies aériennes chez tous les patients (l’obstétrique exclue) suivis par des anesthésistes sur une période de 27 mois. A la période préopératoire, les anesthésistes enregistrent les facteurs propres aux patients et évaluent quatre caractéristiques de leur voies aériennes. On note les méthodes d’intubation endotrachéale et le degré de facilité (facile, malaisée, difficile) de la laryngoscopie directe après l’anesthésie générale (AG). Les facteurs prédictifs de résultats défavorables et la valeur prédictive de l’examen préopératoire des voies aériennes sont déterminés. Chez 18,205 patients, l’intubation sous laryngoscopie directe (AG) a été difficile (> 2 laryngoscopies) dans 1,8% et malaisée (≤2 laryngoscopies) dans 2,5%. Cette approche a échoué dans 0,3% et la chirurgie reportée dans 0,05%. Cependant une alternative à la laryngoscopie directe (AG) a constitué le premier choix chez 353 patients. Les facteurs de risque de l’intubation difficile comprennent le sexe masculin, l’âge de 40 à 59 ans, et l’obésité (P ≤ 0,01). Pour la laryngoscopie directe (AG), les caractéristiques des voies aériennes prédictives d’une intubation difficile sont la réduction de l’ouverture buccale (risque relatif 10,30), la diminution de la distance thyromentonnière (9,7), l’nsuffisance de la visualisation de l’hypopharynx (4,5) et la limitation de l’extension du cou (3,2), deux (7,6) ou plus de deux de celles-ci (9,4) (P < 0,01). Chez 1,856 patients (10,0%), on trouve au moins une caractéristique anormale: chez ceux-ci la laryngoscopie directe (AG) s’avère malaisée dans 8,3% et difficile chez 6,0% des cas. Pour les patients sans anomalies, l’intubation est facile dans 96,3% des cas. Quand l’intubation est difficile, 34,3% des patients ont au moins une caractéristique anormale en préopératoire. Les patients intubés difficilement présentent une désaturation (< 90%) plus fréquente, de l’hypotension (> 200 mmHg) et des dommages dentaires à l’induction de l’anesthésie. En conclusion, les intubations trachéales difficiles surviennent peu fréquemment mais sont associées à une augmentation de la morbidité. Les facteurs propres aux patients et quatre caractéristiques des voies aériennes sont des facteurs prédictifs utiles mais sont insuffisants pour identifier tous les problèmes.
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Supported by a grant from Physicians’ Services Incorporated and by a National Health Scholar Award (Health and Welfare Canada) to Dr. Cohen.
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Rose, D.K., Cohen, M.M. The airway: problems and predictions in 18,500 patients. Can J Anaesth 41, 372–383 (1994). https://doi.org/10.1007/BF03009858
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DOI: https://doi.org/10.1007/BF03009858