超声定位舌骨测量舌颏距离变化率预测困难气道的价值

Value of ultrasonic measurement of hyomental distance ratio for predicting the difficult airway

目的评价超声定位舌骨测量舌颏距离变化率对术前困难气道评估的价值。方法本研究选取104例拟于气管插管全身麻醉下行择期手术的患者,年龄20-76岁,BMI 19-35 kg/m^(2),ASA分级Ⅰ-Ⅲ级。麻醉前行常规气道评估,分别进行人工定位测量甲颏距离(TMD),以及超声定位舌骨测量头颅正常中立位和后仰位舌颏距离,并计算舌颏距离变化率R_(HMD)。麻醉诱导后,以直接喉镜下声门暴露程度为标准,Cormack-Lehane分级1-2定义普通气道组,3-4级定义为困难气道组。应用Youden指数确定舌颏距离变化率预测困难气道的最佳值,以此计算改良Mallampati分级、甲颏距离、舌颏距离变化率预测困难气道的敏感度和特异度。结果困难气道组和正常气道组患者舌颏距离变化率分别为1.21±0.12和1.36±0.14,差异有统计学意义(P=0.0002)。舌颏距离变化率ROC曲下面积为0.757(95%CI 0.613-0.900),最佳截点为1.22;此时准确率、敏感度、特异度分别为64.63%,89.7%和57.9%;改良Mallampati分级预测困难气道敏感度和特异度分别为71.7%和51.4%;甲颏距离预测困难气道敏感度和特异度分别为39.7%和86.7%。结论超声定位舌骨测量舌颏距离变化率,可以做为一种可靠的气道评估方法与其他方法联合应用,以提高术前气道评估的效能。

Objective To evaluate the value of ultrasonic measurement of hyomental distance ratio for predicting the difficult airway.Methods A total of 104 patients(20-76 years old,ASAⅠ-Ⅲ,BMI 19-35 kg/m^(2))undergoing endotracheal intubation and general anesthesia for an elective surgical procedure were enrolled in this study.The clinical screening tests were performed to predict a difficult airway before anesthesia induction.The thyromental distance(TMD)was measured by rulers when the thyroid was located artificially.The hyomental distance was measured by ultrasound while the head was placed in the neutral position and then in a hyperextended position,and the ratio of two distances(hyomental distance ratio,R HMD)was calculated.After anesthesia induction,the difficult airway was defined as Cormack-Lehane grade 3 or 4 under direct laryngoscope during intubation.Youden index was used to determine the optimal value in predicting difficult airway.And the specificity and sensitivity of three methods in predicting difficult airway were calculated based on this criterion.Results The hyomental distance ratio in patients with difficult airway and normal airway were 1.21±0.12 and 1.36±0.14,respectively.Compared with difficult intubation group,the hyomental distance ratio in easy intubation group was significantly increased(P=0.0002).The area under the ROC curve of R HMD was 0.757(95%CI 0.613-0.900)with the best cutoff point of 1.22.The accuracy rate,specificity,and sensitivity of R HMD in predicting difficult airway were 64.63%,57.9% and 89.7%,respectively.The specificity and sensitivity of modified Mallampati classification in predicting difficult airway were 71.7% and 51.4%,respectively.The specificity and sensitivity of thyromental distance in predicting difficult airway were 39.7% and 86.7%,respectively.Conclusion The hyomental distance ratio measured by ultrasonography can be used to predict the difficult airway in combination with other airway assessment methods for increasing the efficacy of airway evaluation before anesthesia induction.