Kaniyil S, et al. - In this prospective, single-blinded comparative observational study including 300 adult patients of either gender scheduled to receive general anesthesia, researchers evaluated ratio of height to thyromental distance (RHTMD) as a predictor of difficult laryngoscopy and compared it with other indices. They evaluated airway indices, like RHTMD, thyromental distance, modified Mallampati test, and upper lip bite test, and correlated with Cormack and Lehane's laryngoscopic grading. They also constructed receiver operating characteristic curves and estimated optimal cutoff value for the quantitative indices. A 5.33% incidence of difficult laryngoscopy was reported. RHTMD was identified as a single best preoperative test for predicting difficult laryngoscopy, among the four indices, with better sensitivity, high specificity, negative predictive value (NPV), and accuracy and with good positive predictive value (PPV). Using indices in combination was recommended in the preoperative airway assessment of adult patients because 100% sensitivity and higher specificity were obtained with a combination of all the indices.