omparing the new Acromio - axillo - suprasternal notch index with modified Mallampati test in the prediction of difficult laryngeal exposure

We aimed to compare the efficacy of a new bedside screening test named Acromio Axillo Suprasternal notch index (AASI) with modified Mallampati test(MMT). 603 adult patients, who were candidates for tracheal intubation under elective surgery, were enrolled in this prospective study. Preoperative airway assessments were carried out with AASI and MMT. The new AASI test is calculated as follow: 1) Using a ruler a line is drawn vertically from the top of the acromion process to the superior border of the axilla at the pectoralis major muscle named as line A.2) A second line is drawn perpendicular to line A from the suprasternal notch (line B); and 3)That portion of line A that lies above where line B bisects line A is line C. AASI is calculated from the length of line C divided by line A(AASI= C/A) After induction of anaesthesia, laryngeal view according to the Cormack- Lehane grading system was recorded.Receiver operating characteristic (ROC) curve analysis was employed to compare AASI with MMT.Difficult visualization of larynx (DVL,Cormack - Lehane III & IV) was observed in 38 (6.3%) of patients. The best cut off point for DVL was defined at AASI≤0.49. AASI had a lower false negative and higher predictive values) compared with MMT. AASI was associated with higher predictive values than MMT and could be recruited for estimation of DVL.