Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 10 2 2024 01 14 113 117 Ahmed Shamim Department of Anaesthesia, Bharati Vidyapeeth (Deemed to be) University Medical College, Pune, India. Sarita Swami Department of Anaesthesia, Bharati Vidyapeeth (Deemed to be) University Medical College, Pune, India. Shweta Konnur Department of Anaesthesia, Bharati Vidyapeeth (Deemed to be) University Medical College, Pune, India. Kalyani Patil Department of Anaesthesia, Bharati Vidyapeeth (Deemed to be) University Medical College, Pune, India. 2023 05 13 2023 06 25 Background: Pre-operative airway assessment for predicting difficult intubation is of utmost importance for anaesthesiologists to ensure adequate oxygenation and ventilation which is a priority. Aims & Objectives: To evaluate the effectiveness of neck circumference (NC) to thyromental distance (TMD) ratio (NC/TMD) as a predictor of difficult intubation and its correlation with established predictors namely Mallampatti grading (MPC grading), Modified Cormack Lehane’s Score (MCLS grading). Methods: 140 patients of age between 18 to 60 years with ASA I, II were selected. Pre-operative, MPC grading and NC to TMD ratio was measured. Intra-operatively, MCLS grading, time taken for intubation, number of attempts taken for intubation, any additional use of equipment required and grading ease of intubation were noted. Correlation was done between them. Results: Out of 140 patients, NC/TMD ratio of >5 was found in 20 patients in which 19 patients required an adjuvant during intubation. NC/TMD ratio had significantly higher sensitivity (75.20) and specificity (99.02) as compared to sensitivity (56.31) and specificity (92.38) of MPC grading. ROC curve for NC/TMD ratio had higher area under curve (AUC = 0.74) than Mallampatti grading (AUC = 0.66). Conclusion: As compared to MPC grading, NC/TMD has emerged out as a better predictor of difficult intubation. https://aacc.tums.ac.ir/index.php/aacc/article/view/768