Ratio of height-to-thyromental distance and ratio of height-to-sternomental distance as predictors of laryngoscopic grade in children

Background and Aims: Failure to secure the airway is an important cause of morbidity and mortality in children. Children are often uncooperative for routine examination and pose problems for obtaining external measurements. We aimed to evaluate ratio of height-to-thyromental distance (RHTMD) and ratio of height-to-sternomental distance (RHSMD) as predictors of laryngoscopic grade in children aged 1–12 years. Material and Methods: This study was an observational study conducted in children aged between 1 and 12 years scheduled for elective surgery under general anesthesia. Children unable to stand, having limited mouth opening/neck mobility, cleft palate or with midline neck masses were excluded. Weight, height, and thyromental and sternomental distances were measured preoperatively. Following induction of anesthesia and full-muscle relaxation, laryngoscopy was performed and Cormack–Lehane view with Cook's modification was noted. Receiver operating characteristic (ROC) curve analysis using RHTMD and RHSMD was performed for predicting poor laryngoscopic view. Results: A total of 138 children with mean age of 6.6 ± 3.4, RHTMD of 17.7 ± 2.1, and RHSMD of 10.0 ± 1.0 were included. No Grade 3 or 4 laryngoscopic views were obtained. ROC curve analysis was done for predicting 2b view (restricted), incidence of which was 10.1%. RHTMD was a better predictor of 2b laryngoscopic view with an area under curve (AUC) of 0.792 compared to RHSMD (AUC = 0.463). Conclusions: In children aged 1–12 years, RHTMD is a better predictor of restricted view compared to RHSMD.