Unanticipated difficult intubation remains a primary concern for anesthesiologists  as failure to secure the airway can cause anesthesia-related life-threatening morbidity and mortality. Difficult laryngoscopy & intubation rate is still as high as 1.5-13% instead of various screening tools.  Ultrasound is a non-invasive, repeatable, portable device which provides improved visualization of airway structure. Hence we aim to study the role of airway ultrasound in predicting difficult laryngoscopy by measuring anterior neck soft tissue thickness and comparing with clinical parameters & Cormack-Lehane grading. We will  sonographically examine the neck of the patient preoperatively and will correlate it with laryngoscopic examination.

Ultrasound measurements will be performed with the patient supine and the head and neck in neutral position by the primary investigator. The thicknesses of anterior neck soft tissue at vocal cord, thyroid isthmus, and supra-sternal notch levels were obtained transversely across the anterior surface of the neck with a 13–6 MHz linear array ultrasound probe attached to a SonoSite machine (SonoSite Inc., Bothell, WA, USA). At vocal cord level (Zone I), the minimal distance from the thyroid cartilage to skin surface & 15mm to the left & right will be measured. At thyroid isthmus level (Zone II), the distance from skin to trachea & 15mm to the left & right was measured. At supra-sternal notch level (Zone III), the minimal distance from skin to trachea & 15mm to the left & right will be obtained. In the operation theatre,  laryngoscopy will be done and Cormack lahane grading will be noted.   The results obtained will be statistically analyzed. Comparison analysis will be performed using the t-test for continuous variables and chi-square or Fisher exact tests, as appropriate, for non-continuous variables. Correlation analysis will be performed using the Pearson test & p value <0.05 will be considered as significant.