Assessment of difficult airway predictors for predicting difficult laryngoscopy and intubation

Abstract

Objectives: The aims and objectives of this study was to study and compare the sensitivity, specificity, positive predictive value, negative predictive value, odds ratio, relative risk, likelihood ratio and accuracy of the following parameters, modified Mallampati grading, interincisor gap, thyromental distance (TMD), ratio of height to thyromental distance (RHTMD), sternomental distance, neck movements, mandibular length and mentohyoid distance for predicting difficult laryngoscopy and/or intubation. Methods: A single blinded prospective observational study involving 100 patients of both gender between 20-70 years of age belonging to ASA physical status I, II and III scheduled to undergo elective surgery under general anaesthesia with endotracheal intubation were recruited for the study. All patients were subjected to the preoperative airway assessment and the above 8 airway parameters were recorded and analysed. The number of intubation attempts were noted. Use of intubation aids were also noted. Conclusion: Upper lip bite test can be used as a simple bedside screening test for prediction of difficult laryngoscopy/intubation but it should be combined with other airway assessment tests. RHTMD is a more accurate test than TMD. Inspite of various airway assessment tests no single test is 100% accurate. So it is advisable to use combination of different tests or the use various scoring systems for predict predicting difficult laryngoscopy/intubation.