Abstract
Purpose
To determine the ability to predict difficult visualization of the larynx (DVL) from the following preoperative airway predictive indices, in isolation and combination: modified Mallampati test (MMT), thyromental distance (TMD), sternomental distance (SMD), horizontal length of the mandible (HLM) and inter-incisor gap(IIG).
Methods
Three hundred and eighty consecutive patients undergoing general anesthesia were evaluated using the MMT, TMD, SMD, HLM and IIG and the cut-off points for the airway predictors were Mallampati III and IV; # 6.5 cm, # 13.5 cm, # 9.0 cm and # 4.0 cm respectively. During direct laryngoscopy, the laryngeal view was graded using the Cormack and Lehane (CL) classification. CL grades III and IV were considered difficult visualization. Sensitivity, specificity and positive predictive value for each airway predictor in isolation and in combination were determined. Logistic regression analysis was used to determine independent predictors of DVL. Results: Difficulty to visualize the larynx was found in 13 (3.4%) patients. The sensitivity, specificity and the positive predictive value for the five airway predictors were: MMT (61.5%; 98.4%; 57.1 %), TMD (15.4%; 98.1%; 22.2%), SMD (0%; 100%; 0%), HLM (30.8%, 76.0%; 4.3%) and IIG (30.8%; 97.3%; 28.6%). The best combination of predictors was MMT/TMD/IIG with a sensitivity, specificity and positive predictive value of 84.6%; 94.6%; 35.5% respectively. Logistic regression analysis showed that weight, MMT, IIG and TMD were independent predictors of DVL.
Conclusion
MMT, TMD and IIG appear to provide the optimal combination in prediction of DVL in a West African population.
Résumé
Objectif
Déterminer la capacité de prédire les difficultés de visuali-sation du larynx (DVL) à partir des indices préopératoires suivants, pris isolément et en combinaison : le test de Mallampati modifié (TMM), la distance thyromentonnière (DTM), la distance sternomentionnière (DSM), la longueur horizontale de la mandibule (LHM) et l’espace inter-incisive (EII).
Méthode
Nous avons évalué 380 patients consécutifs devant subir une anesthésie générale en utilisant le TMM, la DTM, la DSM et l’EII; les points limites des prédicteurs d’intubation ont été les classes de Mallampati III et IV; # 6,5 cm, # 13,5 cm, # 9,0 cm et # 4,0 cm respectivement. La visualisation laryngoscopique directe a été cotée selon la classification de Cormack et Lehane (CL). Les classes de CL III et IV étaient une visualisation difficile. La sensibilité, la spécificité et la valeur prédictive positive de chaque prédicteur d’intubation pris isolé-ment et en combinaison ont été déterminés. On a déterminé les pré-dicteurs indépendants des DVL par l’analyse de régression logistique.
Résultats
La visualisation du larynx a été difficile chez 13 (3,4 %) patients. La sensibilité, la spécificité et la valeur prédictive positive des cinq prédicteurs d’intubation ont été : le TMM (61,5 %; 98,4 %; 57,1 %), la DTM (15,4 %; 98,1 %; 22,2 %), la DSM (0 %; 100 %; 0 %), la LHM (30,8 %; 76,0 %; 4,3 %) et l’EII (30,8 %; 97,3 %; 28,6 %). La meilleure combinaison de prédicteurs a été TMM/DTM/EII avec une sensibilité, une spécificité et une valeur pré-dictive positive de 84,6 %; 94,6 %; 35,5 % respectivement. L’analyse de régression logistique a montré que le poids, le TMM, l’EII et la DTM étaient des prédicteurs indépendants des DVL.
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Merah, N.A., Wong, D.T., Ffoulkes-Crabbe, D.J. et al. Cardiothoracic anesthesia, respiration and airway modified mallampati test, thyromental distance and inter-incisor gap are the best predictors of difficult laryngoscopy in West Africans. Can J Anesth 52, 291–296 (2005). https://doi.org/10.1007/BF03016066
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DOI: https://doi.org/10.1007/BF03016066