Journal of Anesthesia and Surgery
Acromio-Axillo-Suprasternal Notch Index: A New Screening Test to Predict Difficult Laryngoscopy in General Population
- 1Department of Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
Azim Honarmand, Professor, Department of Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran, Tel:0989133136286; E-mail: email@example.com
Honarmand, A., et al. Acromio-Axillo-Suprasternal Notch Index: A New Screening Test to Predict Difficult Laryngoscopy in General Population. (2016) J Anesth Surg 3(4): 1- 6.
© 2016 Honarmand, A. This is an Open access article distributed under the terms of Creative Commons Attribution 4.0 International License
KeywordsAASI; NC; TMD; DVL; Laryngoscopy; RHTMD
Background: Airway management expertness is essential in every medical specialty. Inability to manage Difficult Visualization of Larynx (DVL) can be life threatening. This trail was performed to assess the ability of a new index - Acromio-axillo-suprasternal notch index- to predict difficult laryngoscopy in normal population in comparison with the other common predictors.
Materials and Methods: 728 consecutive patients with ASA class I & II candidate for general anesthesia with endotracheal intubation were enrolled to this study. The four usual tests MMT, ULBT, RHTMD, NC/TMD were assessed before induction of anesthesia. 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). By a skilled anesthesiologist who blinded to the assessment, the laryngoscopy was done and based on Cormack-Lehane classification, garding of laryngoscopy was recorded. Sensitivity, specificity, positive predictive value and AUC or ROC for each airway predictor in isolation and comparison with each other was established.
Results: The sensitivity of AASI was 66.67% with AUC = 0.790(P = 0.000). But MMT as an old predictive test with NC/TMD and RHTMD with AUC or ROC curve 0.626, 0.531, 0.537 respectively, are not good predictors in this study (P > 0.05). But ULBT with sensitivity 52.38% can be a good predictor (P = 0.003). There are stepwise increases in the incidence of Cormack-Lehane grade III and IV as AASI was greater than 0.6.
Conclusion: We considered the value of preoperative assessment of AASI ≥ 0.6 to be a good and reliable predictor for difficult visualization of larynx