Value of hyomental distance measured when the hyoid is located using ultrasound in predicting difficult airway / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the value of hyomental distance (HMD) measured when the byoid was located using ultrasound in predicting the difficult airway.Methods Two hundred and thirteen patients of both sexes,aged 18-64 yr,with body mass index of 14-34 kg/m2,with interincisor distance ＞3 cm,with atlanto-axial joint mobility ＞ 90°,of Mallampati class Ⅰ-Ⅳ,of American Society of Anesthesiologists physical status Ⅰ-Ⅲ,scheduled for elective surgery requiring endotracheal intubation under general anesthesia,were enrolled in the study.The HMD was measured by fingers (finger breaths in width,HMDf) and by rulers (HMDr) when the hyoid was located artificially and when the hyoid was viewed on ultrasound (HMDu) before anesthesia induction.After anesthesia induction,the difficult airway was defined as Cormack-Lehane grade 3 or 4 assessed under direct laryngoscope during intubation.The hyoid viewed on ultrasound was considered as the criterion,and the error rate was calculated when the hyoid was located artificially.Youden Index was used to determine the optimal value in predicting difficult airway,and the specificity and sensitivity of HMDf,HMDr and HMDu in predicting difficult airway were calculated based on this criterion.Results The error rate was 18.8％ when the hyoid was located artificially.The specificity and sensitivity of HMDu in predicting difficult airway were 64.6％ and 91.5％,respectively.The specificity and sensitivity of HMDr in predicting difficult airway were 62.5％ and 84.8％,respectively.The specificity and sensitivity of HMDf in predicting difficult airway was 29.2％ and 98.2％,respectively.Conclusion The HMD measured when the hyoid is located using ultrasound can accurately predict the difficult airway.