Mallampati classification without tongue protrusion can predict difficult tracheal intubation more accurately than the traditional Mallampati classification

IntroductionThe modified Mallampati classification (m-MMT) is the most popular technique for predicting difficult tracheal intubation. However, tongue protrusion may sometimes hide the oropharynx when the distance of the mouth opening is short, and this may lead to false-positive (FP) estimations of difficulty. The purpose of this study is to determine whether the Mallampati classification with no tongue protrusion (NT-MMT) can predict difficult tracheal intubation more accurately than the traditional m-MMT method.MethodsA total of 748 patients requiring endotracheal intubation were enrolled in this study. They were evaluated by m-MMT and by NT-MMT prior to surgery. After induction of general anesthesia with muscle relaxation, all patients underwent direct laryngoscopy, and the best glottic view was recorded as defined by the grading system of Cormack and Lehane. The preoperative assessment data and the intubation findings were used to determine the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the aforementioned tests in predicting difficult intubation.ResultsNT-MMT classification scored higher in all parameters than m-MMT. Similarly, the coefficient of reliability of Spearman's ρ test was higher with NT-MMT than with m-MMT.ConclusionNT-MMT is easy to perform and was more accurate in predicting difficult tracheal intubation than m-MMT.