超声测量舌体积和舌纵截面积预测困难气道的有效性

目的研究超声测量舌体积和舌纵截面积对喉镜暴露困难,以及气管插管困难的预测作用。方法选取需行气管插管全身麻醉的患者120例,男68例,女52例,年龄18~90岁,BMI 16~39 kg/m^2,ASAⅠ-Ⅲ级。麻醉前进行临床气道评估,并超声测量患者的舌纵截面积和舌横径,两者的乘积为超声舌体积。患者麻醉后进行喉镜暴露和气管插管,分析患者的超声舌体积、舌纵截面积和舌横径与喉镜暴露困难以及气管插管困难的关系,采用受试者工作特征(ROC)曲线结合约登指数得到各指标预测喉镜暴露困难和气管插管困难的临界值,根据临界值计算出各指标预测困难气道的准确率、灵敏性、特异性,阳性预测值和阴性预测值。结果本研究共纳入117例患者,喉镜暴露困难31例(26.5%),气管插管困难13例(11.1%)。患者的超声舌体积、舌纵截面积和舌横径均与喉镜暴露困难、气管插管困难相关(P<0.05)。舌纵截面积>18.7 cm^2和舌体积>82.1 cm^3在预测喉镜暴露困难的准确率、灵敏性、特异性、阳性预测值和阴性预测值方面差异均无统计学意义;超声舌纵截面积>19.2 cm^2在预测气管插管困难的准确率和特异性明显低于舌体积>97.4 cm^3(P<0.05),但两指标在灵敏性、阳性预测值和阴性预测值方面差异均无统计学意义。结论超声舌纵截面积和舌体积都能较好地预测喉镜暴露困难和气管插管困难,超声舌纵截面积有望替代舌体积用于预测喉镜暴露困难。

Effectiveness of ultrasound measurement of tongue volume and tongue longitudinal cross-sectional area to predict difficult airway

Objective To investigate the predictive effect of ultrasonic measurement of the tongue volume and the longitudinal cross-sectional area on difficulty in laryngoscope exposure and tracheal intubation. Methods A total of 120 adult patients, 68 males and 52 females, aged 18-90 years, BMI 16-39 kg/m^2, falling into ASA physical status Ⅰ-Ⅲ, undergoing general anesthesia requiring tracheal intubation were enrolled. Before anesthesia, the clinical airway assessment was performed, and the cross-sectional area and the transverse diameter of tongue were measured by ultrasound. The product of the above two indicators was the ultrasonic tongue volume. After general anesthesia laryngoscope exposure and tracheal intubation were performed and recorded. The relationship between the ultrasonic tongue volume, longitudinal cross-sectional area, transverse diameter of tongue and the difficulty in laryngoscope exposure and tracheal intubation were statistically analyzed. The receiver operating characteristic(ROC) curve and Youden′s index were employed to determine the critical values for predicting the difficulty in laryngoscope exposure and tracheal intubation.The accuracy, sensitivity, specificity, positive predictive value and negative predictive value of each indicators were calculated based on the critical values. Results A total of 117 patients were included in the final analyzes. 31 cases(26.5%) experienced difficulty laryngoscope and 13 cases(11.1%) experienced difficult tracheal intubation. The result of statistical analysis revealed that the ultrasonic tongue volume, longitudinal cross-sectional area and transverse diameter of tongue were all related to difficulty in laryngoscopy and tracheal intubation(P<0.05). There was no significant difference in accuracy, sensitivity, specificity, positive predictive value and negative predictive value in predicting the difficulty of laryngoscope exposure when the longitudinal cross-sectional area was greater than 18.7 cm^2 and the ultrasonic tongue volume was greater than 82.1 cm^3. Nevertheless, when the longitudinal cross-sectional area was greater than 19.2 cm^2 and the ultrasonic tongue volume was greater than 97.4 cm^3, the latter excelled in accuracy and specificity of in predicting difficult tracheal intubation(P < 0.05), but no significant difference between the two indicators was observed in sensitivity, positive predictive value and negative predictive value. Conclusion Both the longitudinal cross-sectional area and the volume of tongue measured by ultrasound can predict the difficulty in laryngoscope exposure and tracheal intubation effectively, and the longitudinal cross-sectional area of tongue is expected to replace the tongue volume.