A STUDY OF ACROMIOAXILLO SUPRASTERNAL NOTCH INDEX (AASI) TO PREDICT DIFFICULT VISUALIZATION OF LARYNX

After obtainingapproval from the Institutional Ethics Committee and written informed consentwill be taken from the eligible patients with AmericanSociety of Anesthesiologists’ physical status (ASA PS) I and IIscheduled to undergo elective surgery requiring endotracheal intubation will beenrolled in this prospective observational single-centre study. Each patientwill be assessed before surgery for AASI. During endotracheal intubation thebest laryngoscopy view will be noted according to the Cormack – Lehane (CL)grading system.

AASI will be measured with the patients lying insupine position and the upper limbs resting by the side of the body. Using aruler, a vertical line drawn from the top of the acromion process to the superiorborder of the axilla at the pectoralis muscle (line A). Then a second linedrawn perpendicular to line A from the suprasternal notch [line B]. Theportion of line A that lay above the line B intersects line A will be termed asline C. AASI calculated by dividing the length of line C by that of line A(AASI = C/A). AASI value of >0.49 is considered as a good predictor fordifficult visualization of larynx.

During endotrachealintubation the best laryngoscopy view will be noted according to the Cormack –Lehane (CL)grading system. Grade I = full glottis view; Grade IIa = glottispartly visible, anterior commissure not visualized; Grade IIb = Arytenoids orposterior part of the vocal cord just visible. Grade III = only epiglottis isvisible; Grade IV = no epiglottis visualized. Visualization of CL Grades I andII was inferred as an easy visualization of the larynx (EVL) and CL Grades IIIand IV as difficult visualization of the larynx.