A prospective observational study of the performance of the acromioaxillosuprasternal notch index in predicting difficult visualization of the larynx

Inclusion criteria  Age: 18-60 years , ASA grade -1,2 , Patients undergoing surgery under general anesthesia. Exclusion criteria Patients who denies consent, Patients with prominent features of the difficult airway with facial abnormalities, Morbid obesity body mass index BMI more than 35 kg/sq.m , Restricted mouth opening, edentulous, Cervical spine anomalies, Uncooperative and pregnant patients. Patients with anatomical deformity of head, neck, thorax. After obtaining

approval from Ethics committee Informed and written consent will be obtained from all patients PREOPERATIVE ASSESSMENT  including Detailed history and physical examination, baseline data like heart rate, blood pressure and basic investigations will be collected. Modified mallampatti grading (1,2,3,4), Mouth opening (more or less than 3 finger breath) ,Thyromental distance (more or less than 6.5 cm) , sternomental distance (more or less than 12.5cm) , Hyomental distance (more or less than 4.5 cm), inter incisor distance (more than or less than 4cm ), body mass index  will be noted .An Intravenous  access with 18G IV cannula will be secured for all patients. Premedication such as Tablet Ranitidine 150mg and Tablet Alprazolam 0.5mg given a night before surgery and 6 am on the day of surgery ACROMIO AXILLO SUPRASTERNAL NOTCH INDEX was measured with the patients lying in supine position and their upper limbs resting by the sides of the body Using a ruler  a vertical line was drawn from top of the acromion process to the superior border of the axilla at the pectoralis muscle –line A The second line was drawn perpendicular to line A from the suprasternal notch – line B. The portion of line A that lay above the point at which line B intersected line A was termed as -line C .AASI was calculated by dividing the length of line C by that of line A ( AASI =C/A) . An AASI value of 0.49 or less has been identified as a predictor of difficult laryngoscopy (intubation)