困难气道的查体及评估指南（附翻译）

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建议：专科查体+指南（本文引自心超） Practice Guidelines for Management of the Difficult AirwayA Report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway Anesthesiology 78:597-602, 1993 (c) 1993 American Society of Anesthesiologists, Inc. J.B. Lippincott Company, PhiladelphiaIntroduction Practice guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints. Practice guidelines are not intended as standards or absolute requirements. The use of practice guidelines cannot guarantee any specific outcome. Practice guidelines are subject to revision from time to time, as warranted by the evolution of medical knowledge, technology, and practice.A. Purpose of Guidelines for Difficult Airway Management The purpose of these guidelines is to facilitate the management of the difficult airway and to reduce the likelihood of adverse outcomes. The principal adverse outcomes associated with the difficult airway include (but are not limited to): death, brain injury, myocardial injury, and airway trauma.B. Focus The primary focus of the guidelines is the management of the difficult airway encountered during tracheal intubation.* Some aspects of the guidelines may be relevant in other clinical contexts. The guidelines do not represent an exhaustive consideration of all manifestations of the difficult airway or all possible approaches to management.C. Application The guidelines are intended for use by anesthesiologists and by individuals who deliver anesthetic care under the direct supervision of an anesthesiologist. The guidelines apply to all types of anesthetic care delivered in anesthetizing locations.** The guidelines are intended for patients of all ages.Guidelines I. Evaluation of the Airway History. The literature and consultant opinion strongly support the conduct of an airway history. This support is based upon recognized associations between the difficult airway and a variety of congenital, acquired, and traumatic disease states. The predictive value of the airway history and its effect on outcome have not been clearly defined in the literature. Recommendations: A. An airway history should be conducted, whenever feasible, prior to the initiation of anesthetic care in all patients. The intent of the airway history is to detect medical, surgical, and anesthetic factors that may indicate the presence of a difficult airway. Examination of previous anesthetic records, if available, may provide useful information. Physical Examination. The literature and consultant opinion strongly support the conduct of an airway physical examination. This support is based upon recognized associations between the difficult airway and physical findings. Specific features of the airway physical examination have been incorporated into rating systems that predict the likelihood of a difficult airway. These rating systems exhibit modest sensitivity and specificity. No current rating system is fail-safe. The specific effect of the airway physical examination on outcome has not been clearly defined in the literature. Recommendations: B. An airway physical examination should be conducted, whenever feasible, prior to the initiation of anesthetic care in all patients. The intent of this examination is to detect physical characteristics that may indicate the presence of a difficult airway. Additional Evaluation. The airway history or physical examination may provide indications for additional diagnostic testing in some patients. The literature does not provide a basis for using specific diagnostic tests as routine screening tools in the evaluation of the difficult airway. Recommendations: C. Additional evaluation may be indicated in some patients to characterize the likelihood or nature of the anticipated airway difficulty. The findings of the airway history and physical examination may be useful in guiding the selection of specific diagnostic tests and consultation.II. Basic Preparation for Difficult Airway Management The literature has not rigorously addressed the effects of patient preparation and equipment preparation on outcome. However, there is strong agreement among consultants that preparatory efforts enhance success and minimize risk. The Task Force has identified several fundamental features of preparation that merit consideration. Recommendations: A. At least one portable storage unit that contains specialized equipment for difficult airway management should be readily available. Specialized equipment suggested by the Task Force is listed in table 1. B. If a difficult airway is known or suspected, the anesthesiologist should: 1. Inform the patient (or responsible person) of the special risks and procedures pertaining to management of the difficult airway. 2. Ascertain that there is at least one additional individual who is immediately available to serve as an assistant in difficult airway management. 3. Consider the feasibility of supplemental oxygen administration during the process of difficult airway management. Opportunities for supplemental oxygen administration include (but are not limited to) mask preoxygenation before induction of anesthesia; oxygen delivery by mask, insufflation, or jet ventilation during intubation attempts; and oxygen delivery by mask, blow-by, or nasal cannulae after extubation of the trachea. The uncooperative patient may restrict the opportunities for supplemental oxygen administration, particularly options that involve the application of a mask.III. Strategy for Intubation of the Difficult Airway The literature provides strong evidence that specific strategies facilitate the management of the difficult airway. Although the degree of benefit cannot be determined from the literature, there is strong agreement among consultants that specific strategies lead to improved outcome. Specific strategies can be linked together to form more comprehensive treatment plans or algorithms. The cardiopulmonary resuscitation literature provides evidence for the beneficial effects of algorithms in the management of life-threatening cardiac events. The Task Force considers the technical and physiologic complexity of life-threatening airway events to be sufficiently similar to life-threatening cardiac events to encourage the use of algorithms in difficult airway management. Recommendations: A. The anesthesiologist should have a preformulated strategy for intubation of the difficult airway. This strategy will depend in part upon the anticipated surgery, the condition of the patient, and the skills and preferences of the anesthesiologist. An algorithm recommended by the Task Force is shown in figure 1. B. The strategy for intubation of the difficult airway should include: 1. An assessment of the likelihood and anticipated clinical impact of three basic problems that may occur alone or in combination: a. Difficult intubation. b. Difficult ventilation. c. Difficulty with patient cooperation or consent. 2. A consideration of the relative clinical merits and feasibility of three basic management choices: a. Use of nonsurgical techniques for the initial approach to intubation versus use of surgical techniques for the initial approach to intubation. b. Preservation of spontaneous ventilation during intubation attempts versus ablation of spontaneous ventilation during intubation attempts. c. Awake intubation versus intubation attempts after induction of general anesthesia. 3. The identification of a primary or preferred approach to: a. Awake intubation. b. The patient who can be adequately ventilated but is difficult to intubate. c. The life-threatening situation in which the patient cannot be ventilated or intubated. 4. The identification of alternative approaches that can be employed if the primary approach fails or is not feasible: a. Table 2 displays options for difficult airway management. b. The uncooperative patient may restrict the options for difficult airway management, particularly options that involve awake intubation. Airway management in the uncooperative patient may require an approach (e.g., intubation attempts after induction of general anesthesia) that might not be regarded as a primary approach in a cooperative patient. c. The conduct of surgery using local anesthetic infiltration or regional nerve blockade may provide an alternative to the direct management of the difficult airway, but this approach does not represent a definitive solution to the presence of a difficult airway, nor does it obviate the need for a preformulated strategy for intubation of the difficult airway. 5. The use of exhaled CO2 to confirm tracheal intubation. IV. Strategy for Extubation of the Difficult Airway Although the literature does not provide a sufficient basis for evaluating the merits of an extubation strategy, the Task Force regards the concept of an extubation strategy as a logical extension of the intubation strategy. Consultant opinion strongly supports the use of an extubation strategy. Recommendations: A. The anesthesiologist should have a preformulated strategy for extubation of the difficult airway. This strategy will depend in part upon the surgery, the condition of the patient, and the skills and preferences of the anesthesiologist. B. The preformulated extubation strategy should include: 1. A consideration of the relative merits of awake extubation versus extubation before the return of consciousness. 2. An evaluation for general clinical factors that may produce an adverse impact on ventilation after the patient has been extubated. 3. The formulation of an airway management plan that can be implemented if the patient is not able to maintain adequate ventilation after extubation. 4. A consideration of the short-term use of a device that can serve as a guide for expedited reintubation. This type of device is usually inserted through the lumen of the endotracheal tube and into the trachea before the endotracheal tube is removed. The device may be rigid to facilitate intubation and/or hollow to facilitate ventilation.V. Follow-Up Care Although the literature does not provide a sufficient basis for evaluating the benefits of follow-up care, this activity is strongly supported by consultant opinion. The Task Force has identified several fundamental concepts that merit consideration. Recommendations: A. The anesthesiologist should document the presence and nature of the airway difficulty in the medical record. The intent of this documentation is to guide and facilitate the delivery of future care. Aspects of documentation that may prove helpful include (but are not limited to): 1. A description of the airway difficulties that were encountered. If possible, the description should distinguish between difficulties encountered in mask ventilation and difficulties encountered in tracheal intubation. 2. A description of the various airway management techniques that were employed. The description should indicate the extent to which each of the techniques served a beneficial or detrimental role in management of the difficult airway. B. The anesthesiologist should inform the patient (or responsible person) of the airway difficulty that was encountered. The intent of this communication is to provide the patient (or responsible person) with a role in guiding and facilitating the delivery of future care. The information conveyed may include (but is not limited to): the presence of a difficult airway, the apparent reasons for difficulty, and the implications for future care. C. The anesthesiologist should evaluate and follow the patient for potential complications of difficult airway management. These complications include (but are not limited to): edema, bleeding, tracheal and esophageal perforation, pneumothorax, and aspiration. AppendixA. Definition of the Difficult Airway A standard definition of the difficult airway cannot be identified in the available literature. The Task Force has not given preference to literature based upon any particular system of definition or classification. For these guidelines, a difficult airway is defined as the clinical situation in which a conventionally trained anesthesiologist experiences difficulty with mask ventilation, difficulty with tracheal intubation, or both. The difficult airway represents a complex interaction between patient factors, the clinical setting, and the skills and preferences of the practitioner. Analysis of this interaction requires precise collection and communication of data. The Task Force urges clinicians and investigators to use explicit descriptions of the difficult airway. Descriptions that can be categorized or expressed as numerical values are particularly desirable, as this type of information lends itself to aggregate analysis and cross-study comparisons. Suggested descriptions include (but are not limited to): 1. Difficult Mask Ventilation. 1. It is not possible for the unassisted anesthesiologist to maintain the SpO2 > 90% using 100% oxygen and positive pressure mask ventilation in a patient whose SpO2 was >90% before anesthetic intervention. 2. It is not possible for the unassisted anesthesiologist to prevent or reverse signs of inadequate ventilation during positive pressure mask ventilation. Signs of inadequate mask ventilation include (but are not limited to): cyanosis, absence of exhaled CO2, absence of spirometric measures of exhaled gas flow, absence of breath sounds, absence of chest movement, auscultatory signs of severe airway obstruction, gastric air entry or dilatation, and hemodynamic changes associated with hypoxemia or hypercarbia (e.g., hypertension, tachycardia, arrhythmia). 2. Difficult Laryngoscopy. It is not possible to visualize any portion of the vocal cords with conventional laryngoscopy. 3. Difficult Endotracheal Intubation. 1. Proper insertion of the tracheal tube with conventional laryngoscopy requires more than three attempts. 2. Proper insertion of the tracheal tube with conventional laryngoscopy requires more than 10 min. B. Assessment of Scientific Evidence and Consultant Opinion The assessment of scientific evidence focused on the following 10 statements or linkages. These linkages represent hypotheses about the relationships between clinical care and clinical outcome*** in difficult airway management. 1. Preanesthetic evaluation predicts a difficult airway. 2. Preanesthetic evaluation leads to fewer adverse outcomes. 3. Preparation of the patient and equipment facilitates successful airway management. 4. Preparation of the patient and equipment leads to fewer adverse outcomes. 5. Use of a strategy or algorithm facilitates successful airway management. 6. Use of a strategy or algorithm leads to fewer adverse outcomes. 7. Confirmatory tests of endotracheal intubation facilitate successful management. 8. Confirmatory tests of endotracheal intubation lead to fewer adverse outcomes. 9. Use of an extubation strategy or algorithm leads to fewer adverse outcomes. 10. Follow-up care leads to fewer adverse outcomes. Scientific support for the linkages was assessed by a structured literature search and meta-analysis. The bibliographic files of the National Library of Medicine and other large reference sources were searched for citations containing key words, subject headings, and text entries related to the 10 linkages. Task Force members provided supplemental citations. Several thousand citations were initially identified, of which 537 were associated with the specified linkages. Literature that could not be analyzed was eliminated. A total of 273 articles, published in the interval from 1973 to 1991, were available for consideration. Each article was reviewed, summarized, and coded by the research methodologist using a standardized rating instrument. Agreement between the Task Force members and the methodologist was established by interrater reliability testing. Two approaches to meta-analysis were employed. First, the directional result of each study was classified as either 1) supporting a linkage, 2) refuting a linkage, or 3) neutral. These results were averaged to obtain an aggregate directional measure of support for each linkage. Second, the literature relating to linkages 1, 5, and 6 contained enough studies with well defined experimental designs and statistical information to calculate significance levels for the direction of support. Using the Fisher combined test, the following results were obtained: linkage 1, P < 0.001; linkage 5, P < 0.001; linkage 6, P < 0.01. For this type of meta-analysis, P < 0.01 was considered significant. There were not enough data to assess the relative strength of the directional measures of support. The findings of the literature analysis were supplemented by opinion from Task Force members and 50 consultant anesthesiologists with recognized interest in airway management and guidelines. The kappa statistic was used to obtain a quantitative measure of agreement among consultants. Consultants exhibited strong agreement (kappa >= 0.75) on the potential beneficial effects of the following activities: conduct of the airway history and physical examination, advance preparation of the patient and equipment, formulation of strategies for intubation and extubation of the difficult airway, and provision of follow-up care.C. References A list of the articles used to develop these guidelines is available by writing to the American Society of Anesthesiologists, 520 North Northwest Highway, Park Ridge, Illinois 60068-2573. The process of guideline development was conducted according to the technique described by S. H. Woolf in the Manual for Clinical Practice Guideline Development, U.S. Department of Health and Human Services, March 1991, Agency for Health Care Policy and Research, publication number 91-0007. The Task Force gratefully acknowledges the contributions of the members of the American Society of Anesthesiologists who responded to surveys on difficult airway management, reviewed guideline drafts, contributed oral and written testimony to the Open Forum, and participated in tests of clinical feasibility. Developed by the Task Force on Guidelines for Management of the Difficult Airway: Robert A. Caplan, M.D. (Chairman); Jonathan L. Benumof, M.D.; Frederic A. Berry, M.D.; Casey D. Blitt, M.D.; Robert H. Bode, M.D.; Frederick W. Cheney, M.D.; Richard T. Connis, Ph.D. (Health Services Research Methodologist); Orin F. Guidry, M.D.; and Andranik Ovassapian, M.D. Approved by the House of Delegates, October 21, 1992. To become effective July 1, 1993. Accepted for publication December 1, 1992. Support for guideline development was provided by the American Society of Anesthesiologists, under the direction James F. Arens, M.D., Chairman of the Ad Hoc Committee on Practice Parameters. Address reprint requests to American Society of Anesthesiologists, 520 North Northwest Highway, Park Ridge, Illinois 60068-2573. Key words: Airway: difficult. Intubation: difficult; tracheal. Practice guidelines: difficult airway management. Ventilation: difficult. *See Appendix, Section A, for additional comments on the definition of the difficult airway and related terms. **An anesthetizing location is defined as a physical space in a health-care facility that is specifically equipped and intended for the delivery of anesthetic care. ***See Introduction, Section A, for the principal adverse outcomes associated with difficult airway management. Table 1. Suggested Contents of the Portable Storage Unit for Difficult Airway Management IMPORTANT: The items listed in this table represent suggestions. The contents of the portable storage unit should be customized to meet the specific needs, preferences, and skills of the practitioner and health-care facility. 1. Rigid laryngoscope blades of alternate design and size from those routinely used. 2. Endotracheal tubes of assorted size. 3. Endotracheal tube guides. Examples include (but are not limited to) semirigid stylets with or without a hollow core for jet ventilation, light wands, and forceps designed to manipulate the distal portion of the endotracheal tube. 4. Fiberoptic intubation equipment. 5. Retrograde intubation equipment. 6. At least one device suitable for emergency nonsurgical airway ventilation. Examples include (but are not limited to) a transtracheal jet ventilator, a hollow jet ventilation stylet, the laryngeal mask, and the esophageal-tracheal combitube. 7. Equipment suitable for emergency surgical airway access (e.g., cricothyrotomy). 8. An exhaled CO2 detector. Table 2. Techniques for Difficult Airway Management IMPORTANT: This table displays commonly cited techniques. It is not a comprehensive list. The order of presentation is alphabetical and does not imply preference for a given technique or sequence of use. Combinations of techniques may be employed. The techniques chosen by the practitioner in a particular case will depend upon specific needs, preferences, skills, and clinical constraints. I. Techniques for difficult intubation Alternative laryngoscope blades Awake intubation Blind intubation (oral or nasal) Fiberoptic intubation Intubating stylet/tube changer Light wand Retrograde intubation Surgical airway access II. Techniques for difficult ventilation Esophageal-tracheal combitube Intratracheal jet stylet Laryngeal mask Oral and nasopharyngeal airways Rigid ventilating bronchoscope Surgical airway access Transtracheal jet ventilation Two-person mask ventilation

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菜鸟级翻译，欢迎指正

困难气道的查体及评估指南

系统性发展的临床实践指南，可以协助检查者及病人对医疗保健做出决策。根据临床需要和临床条件，可以采用，改变或拒绝这些建议。

这一指南并不是一个标准或绝对的要求。他的应用并不能保证特定的结果。其以医学知识、技术及操作的革新为保证，一次次的进行修订。

A．困难气道管理指南的目的

这一指南的目的在于：便于困难气道的管理，降低不良愈后的产生。与困难气道有关的不良愈后包括（但不仅仅局限于）：死亡，脑损伤，心肌损伤及气道创伤。

B．焦点

这一指南的关注点在于气管插管过程中所遇到的困难气道的管理。指南中所涉及的一些方面可能与临床情况有关，但它并不能代表对所有困难气道临床表现及所有可应用方法的一个详尽的考虑。

C.应用

这一指南适用于麻醉医师及那些在麻醉医师的监督下进行麻醉管理的个人。

这一指南适用于在麻醉场所进行的所有类型的麻醉管理，也适用于所有年龄段的病人。

Ⅰ 气道的评估

病史

一些文献和专家强调应对气道病史进行了解。这一观点基于：认识困难气道与各种先天性、获得性及损伤性临床疾病之间的联系。而气道病史的预期价值及其对愈后产生的影响并未在文献中得到阐明。

建议：A 所有病人施行麻醉前，应了解其气道病史。这种做法的目的在于：一些内外科及麻醉的因素可能会暗示存在困难气道。如果可行的话，了解患者既往的麻醉记录单，这可能会提供一些有用的信息。

体格检查

一些文献及专家认为应对患者气道进行体格检查。这一观点是基于：认识困难气道与体格检查之间的联系。一些气道体检的特殊因素已经被编入了预测困难气道发生率的评估系统。这一系统，有一定的敏感性及特异性。但现今流行的评估系统都没有自动防故障功能，而这种气道体格检查对愈后的特殊影响，在相关的文献中也并未得到阐明。

建议：B. 对于所有病人，都应在麻醉开始前进行气道体格检查。这一检查的目的在于：一些体检的特征可以暗示存在困难气道。

额外评估：

对于一些病人，气道病史和体格检查可以对额外的诊断测试提供一些线索。在困难气道评估中，文献并不能提供使用特殊的诊断测试作为常规检查方式的依据。

建议：C  在一些病人中，额外的评估可以表明预期困难气道的可能性和特性。而气道病史及体格检查的发现，则在会诊及选择一些特殊的诊断实验时变得非常有用。

Ⅱ. 困难气道管理的基本准备工作

文献中虽未详尽的罗列病人术前准备及仪器准备对愈后的影响，但专家们却达成了一致的共识：即这些准备可以增加成功率并可使风险最小化。TASK FORCE已经阐明了许多值得关注的术前准备的基本特点。

建议：A. 至少有一个便携式贮备单元（包含对困难气道管理的特殊设备）可以随时应用。其建议的特殊设备见表一

B. 如果预知或怀疑有困难气道，麻醉医师应：

1. 告知患者及家属与困难气道相关的特殊风险及程序。

2. 确保至少有一个额外的助手。在困难气道管理时，他可随时作为你的助手。

3. 在困难气道的管理中，考虑辅助供氧管理的可行性。辅助供氧的方法应包括：麻醉诱导前预吸氧；在尝试气管插管期间面罩给氧，吹入法，或喷射通气；以及在拔除气管导管后，经不密闭的面罩给氧，或经鼻导管给氧。不合作的病人，可能会限制辅助供氧的方法，特殊的选择就是面罩的应用。

Ⅲ. 困难气道气管插管的策略

文献提供了有力的证据证明：特殊的策略有助于困难气道的管理，尽管从文献中，仍不能确定其有利程度，但专家们仍认为特殊的策略可以改善愈后。把这些特殊的策略联系在一起，形成更多的综合治疗方案或演绎。心肺复苏的一些文献，已证实演绎对于心脏事件行支持治疗管理的好处。TASK FORCE认为：在困难气道管理中，技术性及生理性气道生命支持治疗与心脏事件生命支持治疗极其相似，都应使用演绎法。

建议：A. 麻醉医师在困难气管插管时，应具备娴熟的策略，这个策略应取决于拟施手术，病人的条件以及麻醉医师的技术和喜好。Task force所建议的一些方法罗列在表1

B. 困难气管插管时的策略应包括：

1.应评估以下3个基本问题所带来的可能或预期的临床影响，这些问题可独立也可一并发生：

a 插管困难
         b 通气困难
         c 病人不合作或不同意

2.相关临床价值的认识及三种基本管理的可行性选择

A．使用无创技术作为初始气管插管方法和使用有创技术作为初始气管插管方法

B．在气管插管过程中保留自主呼吸和不保留自主呼吸

C．清醒气管插管和全麻诱导后气管插管

3.鉴别的主要或首选方法

A．清醒气管插管

B．病人可给予足够的通气但是插管困难

C. 在危及生命的时刻，病人不能通气或不能气管插管

4.当以上这些方法失败或难以实施时，可以选择以下替代方法：

A．表2列出了对困难气道管理的方法

B．不合作的病人可能会限制困难气道管理方法的选择，特别是这些方法中包含清醒的气管插管。对于不合作的病人可以全麻诱导后气管插管，而这种方法在合作的病人，可不作为主要的麻醉方法。

C．一些手术可使用局麻或区域组织，这些方法可能为困难气道患者提供另一种选择，但这种方法并不能代表可以解决困难气道的问题，也不能排除困难气管插管的一些策略性需要。

5. 使用呼气末CO2确认气管导管在气管内

Ⅳ. 困难气道的拔管策略

    虽然文献没有为拔管策略的价值进行足够的评估，但task force认为拔管策略是插管策略的一个延伸。专家们的观点强烈支持应用拔管策略。

建议：a. 麻醉医师应该有一个困难气道的拔管策略，这一策略取决于拟施手术、麻醉医师的技术及爱好。

B．拔管的策略应包括：

1.认识清醒拔管与意识恢复前拔管的相对优势

2.对造成病人拔管后不良影响的临床因素进行评估

3.如果病人拔管后不能维持足够的通气，需要一套系统的弥补措施

4.使用一些短期的设备，这些设备可以引导快速气管导管再插入。在拔出气管导管时，这类设备可以插入气管导管管腔内，并插入气道内。这一设备可以促进气管导管再插入，和或有利通气。

Ⅴ.后续管理

虽然文献并未对后续管理的益处提供明确的评估，但是专家们仍建议进行后续管理。Task force已经明确了许多有价值的基本概念。  

建议：A. 麻醉医师应在临床记录单上以文本形式记录所出现的困难气道及先天性的困难气道。这些记录的目的在于对未来的治疗进行一个引导，并且有利于未来的治疗。在文献中包括了比较实用的方面（但并不仅仅局限于）：

1.对所遇到的困难气道进行描述。如果可以的话，应区分是面罩通气困难还是插管困难。

2.应注明所应用的每一种困难气道管理方法的利与弊。

B. 麻醉医师应告知患着及家属所遇到的困难气道。这种交流的目的在于：为病人及家属在今后的治疗过程中，提供一个指导性的方案。

这些记录所覆盖的信息应包括（但不仅仅局限于）：困难气道的发生，产生困难气道的原因以及对未来治疗的提示。

C. 麻醉医师应评估、追踪病人困难气道管理的潜在并发症。这些并发症包括（但不仅仅局限于）：水肿、出血、气管食管穿孔、气胸。

附录

A.困难气道的定义

困难气道的标准定义在通用的文献中并未得到统一。Task force也并没有给出很好的建议。对于这些指南，困难气道被定义为这样一种临床情况：一个训练有素的麻醉医师难以进行面罩通气、气管插管或二者兼有。困难气道代表了一种复杂的相互作用，这一相互作用产生于病人因素、临床环境以及医生的技术及个人喜好之间。Task foece要求临床人员及调查人员使用对困难气道的明确描述。这种描述要像数值一样可以被分类表达，而这一信息形式也可以得到综合分析及交叉比较。

建议：这种描述应包括（不仅仅局限于）

1.面罩通气困难

       麻醉医师独立操作时，不能使用100%的纯氧和正压面罩通气维持病人的血氧饱和度大于90%，而这些病人在未给予麻醉干预前血氧饱和度大于90%。

       麻醉医师独立操作时，正压面罩通气不能阻止或扭转通气不足的迹象。

      面罩通气不足的迹象包括（但不仅仅局限于）：紫绀、无呼末二氧化碳、absence of spirometric measures of exhaled gas flow

，无呼吸音，无胸廓起伏，有严重气道梗阻的听诊标志，胃进气或胃膨胀，以及与低氧或高碳酸血症相关的血流动力学改变（比如高血压，心动过速，心律失常。）

2.喉镜暴露困难：用传统的喉镜不能看到声门的任何部分

3.困难气管插管：

A.用传统的喉镜进行气管插管需要尝试3次或以上

B.用传统的喉镜进行气管插管需要10分钟或以上

  科学的评估和专家意见

科学的评估和专家意见基于以下10方面或联系。在困难气道管理中，这些联系代表对临床管理和临床预后间关系的假象。

1.麻醉前评估可以预期困难气道

2.麻醉前评估可以降低不良愈后

3.术前行病人准备及设备准备更易成功管理气道

4.术前行病人准备及设备准备降低不良愈后

5.使用一种策略和规则更易成功管理气道

6.使用一种策略和规则可以降低不良愈后

7.气管插管的确定性测试更易成功管理气道

8.气管插管的确定性测试可以降低不良愈后

9.使用拔管策略或法规可减少不良愈后

10术后回访可减少不良愈后

（后面的部分全是统计学，就不翻了）

表一

建议困难气道管理便携存储单元中应包含的内容：

重点：以下所列条目只是一些建议，困难气道便携存储单元中所包含的内容应满足特殊的需要，符合医师的喜好及所擅长的技术以及方便病人管理。

1.常规使用的不同类型、型号的硬质喉镜片

2.各种型号的气管导管

3.气管插管引导设备（比如带或不带中空管芯的半剛性导管可进行喷射通气，光棒，可以控制气管导管远端的医用钳子。）

4.纤维气管插管设备

5.逆行气管插管设备

6.至少有一种设备适用于紧急无创气道通气（比如：经气管的喷射通气，中空的喷射通气设备，喉罩及气管食管联合管）

7.适用于紧急有创气道通气的设备（比如环状软骨切开）

8.呼气末二氧化碳探测仪

表二

困难气道管理的技术

重点：此表中所列为常用技术，并不是一个综合性的列表，所列顺序按字母排序，并不是推荐或应用的顺序，这些技术也可以组合应用。选择应用这些技术时，应取决于操作者的特殊需要、爱好、技术以及临床条件。

     Ⅰ. 困难插管的技术

        可替换的喉镜叶片

        清醒气管插管

        盲插（经口或鼻）

        纤支镜气管插管

        插管可替换管芯

        光棒

        逆行气管插管

        有创气管插管

     Ⅱ. 困难通气的技术

        食管气管联合管

        气管内喷射仪器

        喉罩

        硬质通气气管镜

        有创气管插管

    经气管喷射通气

        双人面罩通气