Comparing the ratios of height-to-thyromental height and height-to-thyromental distance as pediatric laryngoscopic grade predictors– A single center cross-sectional study

Multiple anatomic bedside screening tools are used in children to predict difficult laryngoscopy. Our study compared ratio of height-to-thyromental height (RHTMH) and height-to-thyromental distance (RHTMD) in forecasting children's challenging laryngoscopy grades. This was a single-center, prospective, cross-sectional study in which children aged < 5 years undergoing elective surgery were included. Age, weight, height, body mass index (BMI), TMH, TMD, RHTMH, and RHTMD were documented; Cormack-Lehane grading with Cook's modification grade of laryngoscope view was noted. The primary and secondary outcomes were to determine sensitivity and specificity as well as to determine cut-off values for RHTMH and RHTMD with the highest sensitivity to predict difficult laryngoscopy. One hundred children with a mean age of 2.1 ± 1.6 years, height of 83.17 ± 16.54 cm, weight of 10.47 ± 4.04 kg, and BMI of 14.8 ± 2.68 kg/m2 were analyzed. Mean TMH, TMD, RHTMH and RHTMD were 4.43 ± 0.62 cm, 4.48 ± 0.66 cm, 18.75 ± 2.69, and 18.55 ± 2.51, respectively. At a cut-off of 19.56 (AUC, 0.714; P = .001), RHTMH showed 81.3% sensitivity and 41.2% specificity, while RHTMD had 84.4% sensitivity and 52.9 % specificity at a cut-off value of 19.14 (AUC, 0.724; P = .001) to predict laryngoscopic Grade 2b and above. In children aged < 5 years, both RHTMH and RHTMD were good predictors of difficult laryngoscopy.