Comparison of validity of airway assessment tests for predicting difficult intubation

Abstract

Aim and Objective of the Study: This prospective study was undertaken at Christian Medical College and Hospital Vellore, India. In this study we evaluated the sensitivity and specificity of airway examination tests including: modified Mallampati test (MMT) Thyromental Distance (TMD), ULBT (Upper Lip Bite Test). BMI (Body Mass Index) was also included as one of the predictors. The tests were evaluated individually and in combination. Methods: Total of 354 patients was recruited. Preoperative airway assessments of patients by Mallampati test, Thyromental Distance measurement, ULBT were done. The BMI was also calculated. The tests were done by the investigator and Laryngoscopic grading done by another experienced Anaesthetist according to modified Cormack and Lehane classification. The sensitivity, specificity, positive predictive and negative predictive values were analyzed for the individual tests and in combination. Statistical analysis was performed using SPSS version 11.0. Results: The modified Mallampati had the highest sensitivity of 70% which was statistically significant with a P = 0.001. Conclusion: From this study we conclude that the modified Mallampati test was a better predictor of difficult intubation than the upper lip bite test and Thyromental Distance.