Department of Anesthesiology, Mass General Brigham, Boston, MA.
Department of Anesthesiology, CES University, Medellin, Colombia.
J Cardiothorac Vasc Anesth. 2023 Jul;37(7):1101-1109. doi: 10.1053/j.jvca.2023.02.036. Epub 2023 Mar 2.
This study aimed to review and appraise the evidence regarding airway ultrasound assessment in predicting difficult laryngoscopy in adult patients.
A systematic review of the literature was conducted according to the Cochrane collaboration guidelines and the recommendations for the systematic review and meta-analysis of diagnostic studies. Observational studies that evaluated the diagnostic performance of airway ultrasound for the prediction of difficult laryngoscopy were included for consideration.
Literature searches were performed in 4 databases (PubMed [Medline], Embase, Clinical Trials, and Google Scholar) to identify all observational studies using any ultrasound technique to assess difficult laryngoscopy. The search terms included "sonography," "ultrasound," "airway," "difficult airway," "difficult laryngoscopy," "Cormack," "risk factors," "ultrasound at the point of care," "difficult ventilation," "difficult intubation" and others, combined with sensitive filters. The search was done for studies performed in the last 20 years in English or Spanish.
Adult patients older than 18 years old under general anesthesia for an elective procedure. Evident anatomic airway abnormalities, obstetric populations, those using an alternative imaging method besides ultrasound, and animal studies were excluded.
Preoperative bedside ultrasound measuring distances and ratios from the skin to different reference points, such as the ratio of the hyomental distance in a neutral position (HMDN) and hyomental distance in extension (HMDR), HMDN, and the skin-to-epiglottis distance (SED), the preepiglottic area, and tongue thickness, among others.
A total of 24 studies evaluated the prediction of a difficult laryngoscopy using airway ultrasound. The diagnostic performance and the number of ultrasound parameters reported in the studies were variable. Meta-analysis was performed for 3 measurements consistently included in most studies. The SED and the HMDR ratio presented a sensitivity of 75% and 61%, respectively, and a specificity of 86% and 88%, respectively. The ratio of the preepiglottic distance to the epiglottic distance at the midpoint of the vocal cords (pre-E/E-VC) presented the best performance for predicting a difficult laryngoscopy (sensitivity: 82%, specificity: 83%, diagnostic odds ratio: 22.2).
With the currently available evidence, the 3 commonly used point-of-care ultrasound measures used to identify difficult laryngoscopy, (SED, HMDR, and pre-E/E-VC), showed better sensitivity and similar specificity to clinical measures. Future studies and more data may change the authors' confidence in these conclusions, given the wide variability of measurements noted in studies.
本研究旨在回顾和评估有关气道超声评估在预测成人困难喉镜检查中的证据。
根据 Cochrane 协作组指南和诊断研究系统评价和荟萃分析的建议，对文献进行了系统评价。纳入了评估气道超声预测困难喉镜检查的诊断性能的观察性研究。
在 4 个数据库（PubMed [Medline]、Embase、ClinicalTrials 和 Google Scholar）中进行文献检索，以确定所有使用任何超声技术评估困难喉镜检查的观察性研究。检索词包括“sonography”、“ultrasound”、“airway”、“difficult airway”、“difficult laryngoscopy”、“Cormack”、“risk factors”、“ultrasound at the point of care”、“difficult ventilation”、“difficult intubation”等，结合敏感过滤器。检索了过去 20 年在英语或西班牙语中进行的研究。
在全身麻醉下接受择期手术的年龄大于 18 岁的成年患者。排除明显的解剖气道异常、产科人群、除超声以外的替代成像方法以及动物研究。
术前在床边超声测量从皮肤到不同参考点的距离和比例，例如颏下距在中立位（HMDN）和颏下距在伸展位（HMDR）、HMDN 和皮肤-会厌距离（SED）、会厌前区和舌厚度等。
共有 24 项研究评估了气道超声对困难喉镜检查的预测。研究中报告的诊断性能和超声参数数量各不相同。对大多数研究中一致包含的 3 项测量值进行了荟萃分析。SED 和 HMDR 比值的敏感性分别为 75%和 61%，特异性分别为 86%和 88%。声带中点的会厌前距离与会厌距离之比（pre-E/E-VC）预测困难喉镜检查的性能最佳（敏感性：82%，特异性：83%，诊断优势比：22.2）。
根据目前的证据，3 种常用于识别困难喉镜检查的常用即时护理超声测量值（SED、HMDR 和 pre-E/E-VC），其敏感性优于临床测量值，特异性相似。鉴于研究中注意到的测量值存在广泛的变异性，未来的研究和更多的数据可能会改变作者对这些结论的信心。
