Abstract
Background: Unanticipated difficult intubation or failure of intubation is a major source for anesthesia associated deaths. Hence pre-anesthetic checkup should include a detailed airway evaluation to foresee difficult endotracheal intubation. Some easy bedside tests to predict difficult airway include modified Mallampati test (MMT), ratio of height to thyromental distance (RHTMD), and upper lip bite test (ULBT). Actual difficulty of airway can be estimated using Cormack Lehane (CL) grading while performing laryngoscopy. Combination of two or more bedside clinical tests is used to identify difficult airway and act accordingly.

Aims and Objectives: We aimed at identifying those airway assessment tests which best predicted difficult airway. The objectives were to determine the agreement between MMT, RHTMD, ULBT with CL grading, and also the agreement between MMT and ULBT, MMT and RHTMD.

Materials and Methods: This observational research was done in 88 individuals between 18 and 75 years planned for elective procedures requiring endotracheal intubation as a part of general anesthesia. The clinical assessment tests such as ULBT, RHTMD, and MMT were done on eligible participants during pre-anesthetic check-up. In the operation theater, patient was prepared, premedicated, and induced. CL grading was used to assess the laryngoscopic view. We tried to determine the agreement between MMT, ULBT and RHTMD with CL grading. We also tried to determine the agreement between MMT and ULBT., MMT and RHTMD.

Results: MMT showed moderate, RHTMD showed slight, and ULBT showed no agreement with CL grading. MMT showed highest sensitivity and RHTMD showed highest specificity. No agreement was found for ULBT and RHTMD with MMT.

Conclusion: MMT and RHTMD can be used in predicting difficult airway access; out of which MMT is better than RHTMD. ULBT is not an ideal test to identify difficult endotracheal intubation. Laryngoscopic view becomes difficult with increase in weight and age.

Key words: Modified Mallampati Test; Ratio of Height to Thyromental Distance; Upperlip Bite Test; Cormack and Lehane Grading; Difficult Airway