A Prospective Observational Study Comparing Acromio-Axillo-Suprasternal Notch Index with Modified Mallampatti Class and Neck Circumference / Thyromental Distance Ratio in Predicting Difficult Visualisation of Larynx

Introduction: The prediction of difficult visualization of larynx (DVL) is very important in airway management. A new test, the Acromio-Axillo- Suprasternal notch index (AASI) has been found to be superior to conventional predictors. In this study we have compared the accuracy of AASI with Modified Mallampatti Class (MMPC) and Ratio of Neck Circumference to Thyromental Distance (NC/TMD) among patients from our institution. Methodology: A total of 100 patients of ASA 1 and 2 (18 ? 50yrs), who were candidates for tracheal intubation in elective surgery were enrolled in this Prospective observational study. Pre-operative airway assessment was carried out with AASI, MMPC, NC/TMD. After induction of anesthesia, direct laryngoscopy was done and the laryngeal view was recorded according to Percentage Of Glottic Opening (POGO) scoring system. Results: The positive predictive values, negative predictive values, sensitivity and specificity of AASI vs MMPC vs NC/TMD are 87 vs 80 vs 21 %, 85 vs 85 vs 68 %, 83 vs 78 vs 46 %, 88 vs 86 vs 41 % respectively. Thus, AASI has better Sensitivity, Specificity, Positive and Negative Predictive values compared to MMPC and NC/TMD. Conclusion: This study concludes that AASI can be used as a predictive tool for ?Difficult Visualization of Larynx? (DVL). As no single test predicts DVL precisely, AASI can be used in conjunction with standard tools like MMPC, TMD, NC to increase the validity.