Egan T D, Wong K C
Department of Anesthesiology, University of Utah School of Medicine, Salt Lake City 84132.
Ma Zui Xue Za Zhi. 1993 Sep;31(3):165-78.
Tracheal intubation by direct laryngoscopy is an essential skill for physicians working in the operating room, emergency room or intensive care unit settings. While tracheal intubation can usually be accomplished with ease by direct laryngoscopy, it is sometimes difficult or impossible because of coexisting disease or abnormal physical features. When recognized before attempts at tracheal intubation, virtually all difficult airways can be secured by the selected use of specialized tracheal intubation techniques, although many of these methods require special training, experience, assistance and equipment. When a difficult airway is unrecognized before attempts at intubation the results can be catastrophic because the personnel and equipment necessary for utilizing the specialized tracheal intubation techniques may not be immediately available and the patient's spontaneous respiratory efforts may have been eliminated by anesthetics or muscle relaxants. Thus, identifying patients who are likely to harbor an airway that cannot reliably be secured by simple direct laryngoscopy is an important skill for all acute or critical care physicians. There is an extensive research data base describing historical information, physical examination findings and radiographic features that are associated with the difficult airway. Reviewed collectively, one of the most important underlying concepts suggested by this body of research literature is that the difficult airway is a product of many anatomic and pathologic variables. A surprisingly wide variety of historical, physical examination and radiographic features associated with difficult direct laryngoscopy have been described. A rational approach to airway assessment, therefore, naturally includes a detailed history, a careful physical examination and inspection of relevant x-rays whenever time permits. As outlined in Table 5, there are specific questions to address that may warn the physician about possible airway difficulty. A number of airway assessment schemes based on physical examination findings have been proposed and tested. These schemes vary in their complexity and their clinical convenience. The simpler schemes fail to address the multifactorial nature of the problem, while the more complex systems are clinically impractical. Schemes combining the distance of the thyromental space and the visibility of the oropharyngeal structures, such as that proposed by Frerk, are perhaps the most practical and reliable of the methods proposed to date. Clearly, no one scheme is ideal. At present, preintubation airway evaluation remains a poorly quantified gestalt estimate of the chances for difficulty based on a complex juxtaposition of historical information and physical findings.(ABSTRACT TRUNCATED AT 400 WORDS)
对于在手术室、急诊室或重症监护病房工作的医生而言，直接喉镜下气管插管是一项基本技能。虽然通过直接喉镜通常能轻松完成气管插管，但有时由于并存疾病或身体特征异常，插管会变得困难甚至无法进行。若在尝试气管插管前就识别出困难气道，实际上几乎所有困难气道都可通过选用专门的气管插管技术来确保安全，不过这些方法中的许多都需要特殊培训、经验、协助和设备。若在插管尝试前未识别出困难气道，结果可能是灾难性的，因为使用专门气管插管技术所需的人员和设备可能无法立即到位，且患者的自主呼吸努力可能已被麻醉药或肌肉松弛剂消除。因此，识别那些可能存在无法通过简单直接喉镜可靠确保气道安全情况的患者，是所有急症或重症医生的一项重要技能。有大量研究数据库描述了与困难气道相关的历史信息、体格检查结果和影像学特征。综合来看，这批研究文献所提出的最重要的潜在概念之一是，困难气道是多种解剖和病理变量的产物。已描述了与困难直接喉镜检查相关的惊人多样的历史、体格检查和影像学特征。因此，合理的气道评估方法自然包括详细的病史、仔细的体格检查以及只要时间允许就对相关X光片进行检查。如表5所示，有一些特定问题需要询问，这些问题可能会提醒医生注意可能存在的气道困难。基于体格检查结果，已提出并测试了多种气道评估方案。这些方案在复杂性和临床便利性方面各不相同。较简单的方案未考虑到问题的多因素性质，而较复杂的系统在临床上不实用。结合甲状软骨-颏下间隙距离和口咽结构可视性的方案，比如弗雷克提出的方案，可能是迄今为止所提出的方法中最实用、最可靠的。显然，没有一个方案是完美的。目前，插管前气道评估仍然是以历史信息和体格检查结果的复杂并列为基础，对困难几率进行的一种量化程度不高的整体估计。
