Department of Anesthesiology, Qilu Hospital of Shandong University, 107 Wenhua West Road, Lixia District, Jinan City, Shandong Province, China.
Shenzhen Research Institute of Shandong University, A301 Virtual University Park in South District of Shenzhen, Shenzhen, China.
BMC Anesthesiol. 2022 Oct 10;22(1):314. doi: 10.1186/s12871-022-01855-7.
Difficult endotracheal intubation is one of the most challenging operations in anesthesia. How to better predict difficult airway and make corresponding preparations to reduce the occurrence of accidents is a difficult task faced by anesthesiologists every day. This study decide to evaluate the value of the Upper Lip Bite Test (ULBT) and the Modified Mallampati Test (MMT) in predicting difficult intubation under direct laryngoscopy and find out the most intuitive and simple method to predict difficult intubation under direct laryngoscopy in apparently normal patients.
This descriptive-analytical study was performed on 450 patients for elective surgery under general anesthesia requiring endotracheal intubation. The ULBT and MMT grading were evaluated preoperatively and Cormack and Lehane's (CL) classification was recorded on the day of surgery during intubation under direct laryngoscopy. The accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR), Youden index and area under ROC curve of ULBT and MMT respectively and in combination were calculated and compared. And the consistency between the total scores of ULBT and MMT combined in different ways and CL grading was counted.
Of the 450 patients, 69 (15.3%) were classified as difficult cases of direct laryngoscopy. The accuracy, sensitivity, specificity, PPV and NPV of ULBT were 81.33, 11.59, 93.96, 25.81, 85.44%; and those the corresponding values for MMT were 66.22, 62.32, 69.29, 26.88 and 91.03%. A combination of ULBT and MMT did not improve the sensitivity in the sample tested. The combined total scores of ULBT and MMT in both ways were less consistent with CL grading in predicting difficult intubation under direct laryngoscopy.
Based on findings of current study, we conclude that ULBT and MMT for difficult intubation have only poor to moderate discriminative power when used alone. The combination of the two tests in fractional form is also not a good predictor of difficult intubation under direct laryngoscopy.
Chinese Clinical Trial Registry, ChiCTR2100052987, Registered 07 November 2021, http://www.chictr.org.cn.
困难气管插管是麻醉中最具挑战性的操作之一。如何更好地预测困难气道并做出相应的准备以减少事故的发生，是麻醉医生每天面临的难题。本研究旨在评估上唇咬诊试验（ULBT）和改良 Mallampati 试验（MMT）在预测直接喉镜下困难插管中的价值，并找出一种在明显正常的患者中预测直接喉镜下困难插管最直观、简单的方法。
本研究为描述性分析研究，纳入 450 例择期全身麻醉下需行气管插管的手术患者。术前评估 ULBT 和 MMT 分级，并在直接喉镜下插管时记录 Cormack 和 Lehane （CL）分级。计算并比较 ULBT 和 MMT 各自及联合的准确性、敏感度、特异度、阳性预测值（PPV）、阴性预测值（NPV）、似然比（LR）、Youden 指数和 ROC 曲线下面积，并对不同方式联合的 ULBT 和 MMT 总分与 CL 分级的一致性进行计数。
450 例患者中，69 例（15.3%）被分类为直接喉镜下困难插管病例。ULBT 的准确性、敏感度、特异度、PPV 和 NPV 分别为 81.33%、11.59%、93.96%、25.81%和 85.44%；MMT 相应值分别为 66.22%、62.32%、69.29%、26.88%和 91.03%。在本研究样本中，ULBT 和 MMT 的联合并未提高敏感度。两种方式联合的 ULBT 和 MMT 总分与直接喉镜下预测困难插管的 CL 分级一致性较差。
基于本研究结果，我们得出结论，ULBT 和 MMT 用于预测困难插管的能力较差，仅具有中等至较差的区分能力。两种测试以分数形式联合使用也不能很好地预测直接喉镜下的困难插管。
中国临床试验注册中心，ChiCTR2100052987，注册于 2021 年 11 月 7 日，http://www.chictr.org.cn。
