A Comparison of Cormeck-Lehane and Mallampati Tests with Mandibular and Neck Measurements for Predicting Difficult Intubation

Abstract

Objective: Various prediction tests were formulated to forecast difficult intubation. The Mallampati test, Wilson score, Cormack-Lehane test and thyromental distance are the most commonly used tests pre-operatively to assess the airway. The objective of the present study was to investigate whether a combination of the Mallampati and Cormack-Lehane's classification to predict difficult intubation compared with sternomental and thyromental distances, mandibular length, width and neck length and circumference. Material and Methods: Two hundred twenty seven cases between 17 and 70 years old undergoing elective surgery were included in the study. Age, gender, body weight, body height and BMI were noted preoperatively. The pharyngeal structures were examined before the operation. At the time of intubation, laryngoscopic evaluation was performed according to the Cormack-Lehane's laryngoscopic classification. Results: For analysis, Mallampati and Cormack-Lehane's laryngoscopic classification were grouped as difficult (grades Ill and IV) or easy (grades I and II). Whereas Mallampati scoring were class 1 and 2 (easy) in 72.7% cases, Cormack-Lehane's laryngoscopic scoring 90.7% of the cases were in class 1 and 2. The combination of the Cormeck-Lehane classification with neck circumference had the highest sensitivity (94.74%), but this combination decreased the positive predictive value. The combination of the Mallampati classification with neck length had the highest sensitivity (67.86%), but this combination decreased the positive predictive value. Conclusion: The findings suggest that the Mallampati and Cormeck-Lehane classification by itself is insufficient for predicting difficult intubation so should be used in conjunction with measurement of neck circumference and Cormeck-lehane test. Mallampati test with sternomental and thyromental distances in addition with neck length may be useful in routine test for preoperative prediction of difficult intubation.