Indian Journal of Clinical Anaesthesia 2023;10(2):175–181 Content available at: https://www.ipinnovative.com/open-access-journals Indian Journal of Clinical Anaesthesia Journal homepage: www.ijca.in Original Research Article Thyomental distance is a good difficult airway indicator: Truth or a misconception- A prospective observational study Namratha B 1, *, Apoorva Gupta 1 , Vandana Vasudev 1 , Resham Gupta 1 , Saraswathi P Devi 1 1 Dept. of Anaesthesiology, The Oxford Medical College, Hospital and Research Centre, Bengaluru, Karnataka, India ARTICLE INFO Article history: Received 04-04-2023 Accepted 24-05-2023 Available online 05-06-2023 Keywords: Difficult airway Difficult intubation Thyromental distance ABSTRACT Background and Aims: Unanticipated difficult intubation can be a true challenge to any anaesthesiologist. The most widely used determinant till date in almost every airway study is Thyromental distance[TMD]. We aimed to determine if a TMD above the average values could indicate difficult intubation. Materials and Methods: 70 patients were selected in this prospective observational study who require general anesthesia with endotracheal intubation for their respective surgeries. Patients who fulfilled the inclusion criteria were enrolled in the study and informed written consent was taken. Routine pre-anesthetic check up was done. Thyromental distance was measured [thyroid notch to the lower border of the mandibular mentum-head fully extended] using a rigid ruler. Intraoperatively: After following standard general anaesthesia protocol, patients were intubated by anesthesiologist with atleast 2 years of experience and blinded to the study. The ease (0-5) / Difficulty (>5) in intubation was assessed with Intubation difficulty scale(IDS). Result: Data was analysed using SPSS Software 16. Data was expressed in terms of frequency and percentage. In a total of 70 patients, 18.6% of the patients had difficult intubation. It was observed that 50 patients had a TMD >=7.5 cm out of whom, 7 patients were difficult to intubate. 12 patients had TMD<6.5 cm out of which 6 patients had an IDS of >5 indicating difficult intubation. Sensitivity, specificity, PPV, NPV were calculated. Categorical Pearson chi square test was done for TMD>7.5 vs IDS and it showed a p value of 0.017 (p<0.05). Conclusion: We observed that a long TMD (TMD>=7.5cm) could be a difficult airway indicator just like a short TMD (TMD<=6.5). Therefore, our findings suggest that thyromental distance may not have a significant role as a standalone pre-operative indicator of a difficult airway and its reliability as a useful parameter in predicting difficult intubation is questionable. This is an Open Access (OA) journal, and articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms. For reprints contact: reprint@ipinnovative.com 1. Introduction The management of a difficult airway is a significant challenge for any anaesthesiologist, and it remains a major source of morbidity and mortality in anesthesia practice. 1 The early identification and preparation is critical in reducing the risk of airway-related complications and * Corresponding author. E-mail address: namu9492@gmail.com (Namratha B). fatalities. To date, the most commonly used determinant in almost every airway research is thyromental distance 2 [TMD] and most studies have considered a short TMD of less than 6.5 cms as a predictor of difficult intubation. 3–5 However, its predictive value has been subject to some debate, with conflicting results reported in the literature. Despite this, TMD continues to be widely used as a screening tool for difficult airway management due to its https://doi.org/10.18231/j.ijca.2023.034 2394-4781/© 2023 Author(s), Published by Innovative Publication. 175