Modified Mallampati Test, Thyromental Distance and Hyomental Distance for Accurately Predicting Difficult Visualization of the Larynx.

ABSTRACT

Background: This study has been done to compare Hyomental distance with the modified Mallampati test, Thyromental distance for accurately predicting difficult visualization of the larynx in apparently normal patients’. Methods: 198 apparently normal patients of > 18 years of age, with ASA 1 and 2, undergoing general anaesthesia with tracheal intubation were evaluated. A hard-plastic bond ruler is used to measure the distance. After induction and paralysis using glottic visualisation was assessed by using modified Cormach and Lehane classification with no external laryngeal manipulation. Results: The highest sensitivity of 44.44 % was observed in predicting difficult visualization of the larynx with modified Mallampati followed by TMD 11.11 % and HMD 11.11 % (2/18). Conclusion: An optimal combination of tests that includes the HMD,MMT,TMD and other predictors and performing the tests in combination for predicting Difficult Laryngoscopy, rather than using it alone.