Abstract PR529

Abstract

Background & Objectives: Airway management remains one of the most important responsibilities of an anaesthesiologist. The purpose of this study was to compare preoperative anaesthetic airway evaluation methods of Modified Mallampati Test (MMT) and Upper Lip Bite Test (ULBT) to predict difficult intubation with the direct laryngoscopy views obtained during tracheal intubations. Materials & Methods: 200 patients (of either sex aged between 18 years and 55 years) undergoing elective surgical procedures under general anaesthesia with endotracheal intubation were evaluated for both tests before surgery. An experienced anesthesiologist, unaware of preoperative airway evaluation, performed the laryngoscopy and grading (as per Cormack and Lehane’s classification). Sensitivity, specificity, accuracy, positive and negative predictive values of upper lip bite test and Modified Mallampati test were calculated. Results: On comparing both the tests, we found that, MMT is more sensitive (75.00%) than ULBT (25.00%), both tests had high specificity (MMT 91.30%; ULBT 95.11%). Positive predictive value was 42.86% for MMT while it was 30.77% for ULBT. Similarly negative predictive value was 97.67% and 93.58% for MMT and ULBT respectively. Accuracy of MMT was 90.00% for MMT while it was 89.5% for ULBT. Conclusion: Both the tests are poor predictors of difficult intubation (low positive predictive values) when used as single preoperative bedside screening tests. MMT is a better test at predicting difficult endotracheal intubation when compared to ULBT. Both the tests are better predictors of easy intubations rather than difficult intubations (high negative predictive value).