Accuracy of thyromental height in predicting difficult airway / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the accuracy of thyromental height (TMH) in predicting difficult airway.Methods Three hundred and thirty patients of both sexes requiring endotracheal intubation,aged ＞18 yr,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,scheduled for elective surgery under general anesthesia,were selected.The modified Mallampati test (MMT) score,thyromental distance (THD),sternomental distance (SMD) and TMH were measured following admission to the operating room.Direct laryngoscope was placed after induction of anesthesia to expose the glottis,and the Cormack-Lehane grade was recorded.Difficult airway was defined as Cormack-Lehane grade Ⅲ or Ⅳ.The receiver-operating characteristics curve was used to evaluate the accuracy of MMT,THD,SMD and TMH in predicting difficult airway.Results The diagnostic threshold of TMH in predicting difficult airway was 39.04 mm,the sensitivity 88.24％,the specificity 90.42％,the area under the curve (95％ confidence interval) 0.897 (0.859-0.928),and the odds ratio 70.750.Compared with MMT,THD and SMD,the area under the curve of TMH in predicting difficult airway was significantly increased (P＜0.05).Conclusion TMH can accurately predict difficult airway,and the diagnostic threshold is 39.04 mm in patients.