Predicting Difficult Laryngoscopy by Ultrasound Quantification of Anterior Neck Soft Tissue Thickness-A Prospective Observational Study

Abstract

Introduction: Difficult airway can possess a challenge to intubation and deciding role in morbidity and mortality. Hence, at these times Ultrasonography (USG) can play a vital role in the prediction of a difficult airway. Aim: To determine if USG measurement of anterior neck soft tissue thickness at the hyoid bone, and anterior commissure levels can be used to predict difficult laryngoscopy. Materials and Methods: The prospective observational study was carried out from January 2021-January 2022. There were 50 patients, aged 20-60 years, and scheduled to undergo general anaesthesia. Correlation analysis between roles of screening tests like Mallampati scoring (MMP), Cormack Lehane (CL) grade Neck Circumference (NC), Thyromental Distance (TMD) and USG measurements was done for predicting difficult laryngoscopy. Portable USG machine with a linear frequency probe, measuring tape and laryngoscope blade was required. The data was analysed using Statistical Package for Social Sciences (SPSS) version 22. Results: The incidence of difficult laryngoscopy was 18% and the mean age of the study participants in the easy group was 44.26 years and in the difficult group it was 45.13 years. The USG measurements were significant (p-value=0.01) in determining difficult intubation, which shows greater validity to predict difficult laryngoscopy. Hence, USG measurement along with bedside screening test aids in better identification and assessment of difficult airway. Conclusion: Anterior neck soft tissue thickness measured by USG at the hyoid bone, and anterior commissure levels combined with the screening tests and risk factors might increase the ability to predict difficult airways.