Comparison of acromioaxillosuprasternal notch index (a new test) with modified Mallampati test in predicting difficult visualization of larynx

Maintaining a patent airway following the induction of general anesthesia is undeniably the most imperative concern for an anesthesiologist. Unanticipated difficult intubation, especially when associated with difficult or lack of ventilation in anesthetized patients, is still the main cause of morbidity or mortality.¹

The incidence of difficult laryngoscopy or tracheal intubation was reported to be in the range of 0.1–20.2%; this variation is due to the different patient populations and criteria used.^{2, 3, 4, 5, 6, 7, 8, 9} Prediction of difficult intubation in preoperative evaluation has been attempted by numerous investigators using simple bedside physical examinations based on anatomical landmarks such as modified Mallampati test (MMP), interincisive distance, thyromental distance (TMD), sternomental distance, upper lip bite test, and hyomental distance ratio,^{3, 7, 10, 11} all of which have shown different sensitivities and specificities.

In the authors' experience, difficult visualization of larynx (DVL) was observed in individuals whose neck was situated deep in the chest (i.e., with a sloping clavicle); therefore, to consider a bedside test based on surface anatomy is suggested. We observed that the portion of the arm–chest junction above the level of suprasternal notch might be used as an indicator to estimate DVL. This study was aimed to evaluate the predictive validity of a new index (based on the surface anatomy of the upper chest), called the acromioaxillosuprasternal notch index (AASI), and compare it with a previously established test (MMP) for assessing difficult laryngoscopic view in patients who were candidates for general anesthesia.

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