困难气道预测模型的研究进展

气道管理是临床麻醉工作的核心内容。气道管理不足会导致患者发生缺氧、低氧性脑损伤等并发症。麻醉科医师在临床工作中常遇到困难气道,充分的术前评估对发现潜在困难气道至关重要,目前国内外均缺乏稳定可靠的困难气道风险预测模型。本文主要从外观指标、外观预测模型、影像学指标三个方面阐述困难气道的研究进展,为气道管理工作以及未来搭载人工智能建立困难气道预测模型提供参考。     

Diagnostic accuracy of anaesthesiologists’ prediction of difficult airway management in daily clinical practice: a cohort study of 188 064 patients registered in the Danish Anaesthesia Database

Both the American Society of Anesthesiologists and the UK NAP4 project recommend that an unspecified pre‐operative airway assessment be made. However, the choice of assessment is ultimately at the discretion of the individual anaesthesiologist. We retrieved a cohort of 188 064 cases from the Danish Anaesthesia Database, and investigated the diagnostic accuracy of the anaesthesiologists’ predictions of difficult tracheal intubation and difficult mask ventilation. Of 3391 difficult intubations, 3154 (93%) were unanticipated. When difficult intubation was anticipated, 229 of 929 (25%) had an actual difficult intubation. Likewise, difficult mask ventilation was unanticipated in 808 of 857 (94%) cases, and when anticipated (218 cases), difficult mask ventilation actually occurred in 49 (22%) cases. We present a previously unpublished estimate of the accuracy of anaesthesiologists’ prediction of airway management difficulties in daily routine practice. Prediction of airway difficulties remains a challenging task, and our results underline the importance of being constantly prepared for unexpected difficulties.     

Prediction of difficult mask ventilation using a systematic assessment of risk factors vs. existing practice – a cluster randomised clinical trial in 94,006 patients

We compared implementation of systematic airway assessment with existing practice of airway assessment on prediction of difficult mask ventilation. Twenty‐six departments were cluster‐randomised to assess eleven risk factors for difficult airway management (intervention) or to continue with their existing airway assessment (control). In both groups, patients predicted as a difficult mask ventilation and/or difficult intubation were registered in the Danish Anaesthesia Database, with a notational summary of airway management. The trial's primary outcome was the respective incidence of unpredicted difficult and easy mask ventilation in the two groups. Among 94,006 patients undergoing mask ventilation, the incidence of unpredicted difficult mask ventilation in the intervention group was 0.91% and 0.88% in the control group; (OR) 0.98 (95% CI 0.66–1.44), p = 0.90. The incidence of patients predicted difficult to mask ventilate, but in fact found to be easy (‘falsely predicted difficult’) was 0.64% vs. 0.35% (intervention vs. control); OR 1.56 (1.01–2.42), p = 0.045. In the intervention group, 86.3% of all difficult mask ventilations were not predicted, compared with a higher proportion 91.2% in the control group, OR 0.61 (0.41–0.91), p = 0.016. The systematic intervention did not alter the overall incidence of unpredicted difficult mask ventilations, but of the patients who were found to be difficult to mask ventilate, the proportion predicted was higher in the intervention group than in the control group. However, this was at a ‘cost’ of increasing the number of mask ventilations falsely predicted to be difficult.     

Airway events in obese vs. non-obese elective surgical patients: a cross-sectional observational study

Obesity is an increasingly prevalent comorbidity within the UK population. The aim of this study was to determine the proportion of obese patients in an elective surgical population. The second aim was to determine the choice of airway equipment and incidence of airway events in obese vs. non-obese patients. We conducted a cross-sectional observational study over two 24-h periods in March 2018 across 39 hospitals in the greater London area. Data were collected regarding 1874 patients. The incidence of obesity was 32% in the study population compared with 26% in the general UK population (p < 0.0001). Minor airway events were defined as: desaturation to S_pO₂ < 90%; failed mask ventilation; supraglottic airway device problem; aspiration; airway trauma and difficult intubation; or recognised oesophageal intubation. Major airway events were defined as: unrecognised oesophageal intubation; a ‘cannot intubate cannot oxygenate’ emergency; the need for unplanned front-of-neck airway; cardiac arrest; or unplanned intensive care unit admission due to an airway event. In total, 89 minor and two major airway events were recorded. Obese patients were more likely to experience a minor airway event (RR 2.39, 95%CI 1.60–3.57), the most common being desaturation (S_pO₂ < 90%). The use of a supraglottic airway device in obese vs. non-obese patients was associated with increased airway events (RR 3.46 [1.88–6.40]). Tracheal intubation vs. supraglottic airway device use increased with obesity class but was not associated with a decrease in airway events (RR 0.90 [0.53–1.55]). Our data suggest that obesity is more common in the elective surgical vs. general population and minor airway events are more common in obese vs. non-obese elective patients.     

Case series: The McGrath® videolaryngoscope — an initial clinical evaluation

PURPOSE: To document tracheal intubation success rates and airway instrumentation times using the newly designed McGrath videolaryngoscope. METHODS: We prospectively recorded factors associated with difficult tracheal intubation, factors causing actual difficulty in tracheal intubation, as well as complications arising from use of the new McGrath videolaryngoscope in a series of adult patients with normal preoperative airway examinations. All patients were undergoing scheduled or elective surgery. In the first 75 patients (phase I), experience with airway instrumentation was documented, while in the second 75 patients (phase II), the time required to obtain an optimal view of the larynx was recorded, as well as the time to complete tracheal intubation. RESULTS: Ninety-eight percent of all tracheal intubations were successful using the McGrath videolaryngoscope. Cormack and Lehane grade I views were obtained in 143 patients (95%) and grade II views were achieved in six (4%). In phase II, the median time required to obtain an adequate view was 6.3 sec [interquartile range 4.7-8.7 (range 2-26.3)], and to complete tracheal intubation was 24.7 sec [18.5-34.4 (11.4-286)]. Fortynine (65%) of the tracheal intubations were completed within 30 sec, and 72 (96%) were completed within one minute. No complications were encountered in any patient. CONCLUSIONS: The McGrath videolaryngoscope is an effective aid to airway management in patients with normal airways, based upon intubation success rates and the ability to rapidly secure the airway. Its potential advantages of convenience and portability warrant further evaluation in comparison with other airway devices and in patients with difficult airways.     

Can we make airway management (even) safer?--lessons from national audit

The Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society (NAP4) has published an extensive report examining both current practices in the United Kingdom regarding airway management during anaesthesia and the complications of airway management during anaesthesia and in intensive care units and emergency departments. The report makes more than 160 recommendations designed to improve care of patients. These recommendations have implications for individuals, departments, organisations and potentially for national policy in terms of training, standards of practice and the need for guidelines. The report also indicates several specific areas where future research might be directed. This article focuses on the implementation phase of NAP4, emphasising the importance of taking the lessons derived from NAP4 and turning them into actions to improve the safety of airway care delivered to patients, wherever in hospital this takes place.     

中国医疗机构困难气道的调查与分析

目的通过网络问卷对全国31个省、市、自治区的医疗机构气道管理情况进行调查。方法拟定一份有关气道管理情况的网络调查问卷,包含9大类63个问题,通过微信发放和回收。结果回收问卷1 935份,有49.7%的被调查者来自三级医院,主治医师及以上占75.7%。63.2%的参与者曾因困难气道而取消或延迟手术。13.8%调查者所在医院发生过因困难气道导致严重不良事件(患者死亡或脑损伤等)。肥胖(26.2%)是困难气道最常见原因。对已预见的困难气道,选择全麻快速诱导比例达16.9%。未阅读ASA和CSA困难气道管理流程比例为34.3%和6.8%。对于未预料困难气道,盲探3次及以上的比例为2.5%。手术室外插管时,69.8%的参与者认为最担心困难气道。36.1%的参与者曾使用过颈前急救技术抢救患者。最常采用的技术是环甲膜穿刺技术,达74.4%。73.0%配备可视喉镜,可视插管软镜(含纤维支气管镜和电子镜)比例达到52%,气道急救箱或急救车比例34.1%。79.8%的医师经历过拔管后再插管。仅50.9%参加过气道管理培训。结论气道工具配备虽有明显改善,但因困难气道导致的严重并发症依然存在;紧急气道急救工具普遍缺乏,困难气道管理培训有待普及,困难气道管理仍然需不断改善。     

Monitoring during difficult airway management

Monitoring is crucial to assure safety during difficult airway management. Several reports have indicated that the most of the adverse outcomes associated with difficult airway management could have been avoided with the use of necessary monitors, such as a pulse oximeter and a capnometer. Nevertheless, airway complications continue to be major problems during anesthesia, in particular, in patients with difficult airways. In this brief review, I stress the role of monitoring in detecting inadvertent esophageal intubation, during sedation for awake tracheal intubation, during general anesthesia, and during emergence from anesthesia, in patients with difficult airways.     

Lightwand intubation: II — Clinical trial of a new lightwand for tracheal intubation in patients with difficult airways

Lightwands have been used to assist in the tracheal intubation of patients with difficult airways for many years. A new lightwand (Trachlight?) with a brighter light source and a flexible stylet permits both oral and nasal intubation under ambient light. This study reports the effectiveness of the Trachlight? in tracheal intubation in patients with difficult airways. Two groups of patients were studied: Group 1 — patients with a documented history of difficult intubation or anticipated difficult airways; Group 2 — anaesthetized patients with an unanticipated failed laryngoscopic intubation. In Group I, the tracheas were intubated using the Trachlight? with patients either awake or under general anaesthesia. In Group 2, tracheas were intubated under general anaesthesia using the Trachlight?. The time-to-intubation, number of attempts, failures, and complications during intubation for all patients were recorded. Two hundred and sixty-five patients were studied with 206 patients in Group 1, and 59 in Group 2. In most patients, the tracheas were intubated orally (183 versus 23 nasal) during general anaesthesia (202 versus 4 awake) in Group 1. Intubation was successful in all but two of the patients with a mean (± SD) time-to-intubation of 25.7 ± 20.1 sec (range 4 to 120 sec). The tracheas of these two patients were intubated successfully using a fibreoptic bronchoscope. Orotracheal intubation was successful in all patients in Group 2 using the Trachlight? with a mean (± SD) time-to-intubation of 19.7 ± 13.5 sec. Apart from minor mucosal bleeding (mostly from nasal intubation), no serious complications were observed in any of the study patients. With proper preparation, this study has demonstrated that Trachlight? is an effective and safe device to intubate the tracheas of elective surgical patients with a history of difficult airway in experienced hands.     

Human factors in the development of complications of airway management: preliminary evaluation of an interview tool

The 4th National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society (NAP4) analysed reports of serious events arising from airway management during anaesthesia, intensive care and the emergency department. We conducted supplementary telephone interviews with 12 anaesthetists who had reported to NAP4, aiming to identify causal factors using a method based on the Human Factors Investigation Tool (HFIT). We identified contributing human factors in all cases (median [range] 4.5 [1–10] per case). The most frequent related to: situation awareness (failures to anticipate, wrong decision) (nine cases); job factors (e.g. task difficulty; staffing, time pressure) (eight cases); and person factors (e.g. tiredness, hunger, stress) (six cases). Protective factors, such as teamwork and communication, were also revealed. The post‐report HFIT interview method identified relevant human factors and this approach merits further testing as part of the investigation of anaesthetic incidents.     

Hemifacial microsomia: anatomical prediction of difficult intubation

Hemifacial microsomia (HFM) is associated with a difficult airway. We hypothesized that a difficult intubation would be predicted by radiographic evaluation of the severity of mandibular hypoplasia. A retrospective review of anaesthetic and surgical records of 102 children with HFM from 1986 to 1996 was conducted for radiographic classification of mandibular hypoplasia and degree of difficulty with intubation. Intubation was classified as Grade A-easy, Grade B-difficult, or Grade C-very difficult. The mandibular anatomy was categorized as Type I-'mini-mandible', Type II-abnormal condylar size and shape, or Type III-absent ramus, condyle, and temporomandibular joint. In the 82 patients with HFM, 70% were classified as Grade A, 21% had Grade B and 9% had Grade C airways. No patients with Type I mandible had Grade C airway, while 25% of the patients with Type III mandible had Grade C airway. The correlation of the degree of airway difficulty with mandibular type was significant (P=0.001). In 20 patients with bilateral mandibular hypoplasia, 30% had Grade A, 35% had Grade B, and 35% had Grade C airways. We conclude that radiographic classification of mandibular deformity is a useful adjunct for preoperative prediction of airway difficulty in the management of children with unilateral HFM.     

Flexible lightwand-guided tracheal intubation with the intubating laryngeal mask Fastrach in adults after unpredicted failed laryngoscope-guided tracheal intubation

BACKGROUND: The authors determined the efficacy of using the intubating laryngeal mask airway Fastrach (ILM) as a ventilatory device and aid to flexible lightwand-guided tracheal intubation in patients with unpredicted failed laryngoscope-guided tracheal intubation when managed by experienced anesthetists. METHODS: During a 27-month period, 16 experienced anesthetists agreed to use the ILM as an airway device and airway intubator in patients (aged > 18 yr) with predicted normal airways who were subsequently found to be difficult to intubate (three failed attempts at laryngoscopy). Intubation via the ILM was performed with a flexible lightwand. The number of attempts at ILM placement, the number of adjusting maneuvers, the number of attempts at tracheal intubation via the ILM,and any episodes of hypoxia (oxygen saturation < 90%) were recorded. RESULTS: Forty-four of 11,621 patients (0.4%) met the inclusion criteria. ILM insertion and ventilation was successful at the first attempt in 40 of 44 patients (91%) and at the second attempt in 4 of 44 (9%). Flexible lightwand-guided tracheal intubation via the ILM was successful in 38 of 44 patients (86%) at the first attempt, 3 of 44 (7%) at the second attempt, 2 of 44 (5%) at the third to fifth attempts, and failed in 1 of 44 (2%). The median number of adjusting maneuvers before successful intubation was 1 (range, 0-4). Hypoxia occurred in 5 patients before ILM insertion (range, 52-82%), but none after ILM insertion. No patient developed hypoxia during or after intubation via the ILM. CONCLUSION: The ILM is an effective ventilatory device and aid to flexible lightwand-guided tracheal intubation in adult patients with predicted normal airways in whom laryngoscope-guided tracheal intubation subsequently fails when managed by experienced anesthetists.     

Evaluation of the Augustine Guide™ for difficult tracheal intubation

Successful tracheal intubation with Augustine Guide ? (Augustine Medical, Inc., Eden Prairie, MN) in patients with normal airways has recently been described. There are no studies describing Augustine Guide (AG) use in patients with difficult airways. Accordingly, we studied AG intubation in a population of patients with expected difficult airways due to cervical spine pathology, limited mouth opening, obesity, facial trauma or deformity due to previous operation or radiation and in patients with unexpectedly difficult airways. A total of 44 patients were studied. The AG was used as a primary intubating tool in patients with known difficult airways (n = 36) and as a secondary intubating tool in patients with unexpected inability to intubate using conventional direct laryngoscopy (n = 8). Airway difficulty was predicted by history and physical examination. Intubations were performed under general anaesthesia in 40 of the 44 patients studied. In four patients with predictably difficult airways, topical anaesthesia and sedation were used. Backup methods to achieve intubation were available. Thirty-two of the 36 with known or suspected difficult airways were classified as Mallampati Class III or IV. In the remaining eight patients the preoperative examination suggested an easy airway; however, after induction of general anaesthesia, their laryngeal inlet could not be seen using direct laryngoscopy. Using the AG, all were intubated successfully (36/44 at the first attempt, in 8/44 repositioning of the AG to allow successful laryngeal entry of the stylet was necessary). There were no failures or complications secondary to AG use. This study shows that the AG is a useful device for oral tracheal intubation in patients with known or unexpectedly difficult airways.     

The intubating laryngeal mask airway after induction of general anesthesia versus awake fiberoptic intubation in patients with difficult airways

We performed the current study to compare tracheal intubation (TI) using awake fiberoptic intubation (AFOI) and TI using the intubating laryngeal mask airway (ILMA) in patients with difficult airway. Our hypothesis was that patients with difficult airways could be safely intubated after induction of anesthesia using the ILMA. After ethics approval and informed consent, 38 patients who were identified to have difficult airways were randomly assigned to AFOI or TI using the ILMA. Patients in the AFOI group had the usual sedation and airway topicalization. Patients in the ILMA group were induced with propofol for ILMA insertion and succinylcholine for TI. The first TI attempt was done blindly via the ILMA and all subsequent attempts were performed with fiberoptic guidance. All patients in the ILMA group were successfully ventilated. Successful TI was achieved in all patients in both groups. However, in 10% of the patients in the ILMA group, TI was achieved by a second anesthesiologist who was more experienced with the use of the ILMA. In a postoperative questionnaire, patients in the ILMA group were more satisfied with their method of TI (P < 0.01). The ILMA is a useful device in the management of patients with difficult airways and may be a valuable alternative to AFOI when AFOI is contraindicated or in the patient with the unanticipated difficult airway. IMPLICATIONS: The intubating laryngeal mask airway is a useful device in the management of patients with difficult airways and may be a valuable alternative to awake fiberoptic intubation (AFOI) when AFOI is contraindicated or in the patient with the unanticipated difficult airway.     

Fiberoptic intubation through an I-gel supraglottic airway in two patients with predicted difficult airway and intellectual disability

We describe successful fiberoptic-guided tracheal intubation through the novel supraglottic "I-gel" airway in two uncooperative adult patients with genetic syndromes, learning disability, and predicted difficult airway, scheduled for complex dental treatment under general anesthesia. The I-gel maintained the airway immediately after induction, allowing oxygenation and ventilation. Location of the laryngeal inlet was successful on the first attempt with a fiberscope, and the tracheal tube was inserted into the trachea over the endoscope without complication in both patients. This report suggests another option for management of predicted difficult airways.     

Retrospective audit of the air-Q intubating laryngeal airway as a conduit for tracheal intubation in pediatric patients with a difficult airway

Objectives: To assess the efficacy of the ILA as a conduit for tracheal intubation in pediatric patients with a difficult airway. Aim: The primary goals of this retrospective audit were to assess the clinical performance of the ILA in pediatric patients with a difficult airway, expand on our initial favorable experience with this device, and collect pilot data for future prospective and comparison studies. Methods: The charts of patients with a difficult airway in whom the ILA was used during a period of 1 year in a freestanding pediatric institution were reviewed following a practice change in the authors’ institution favoring the ILA over the laryngeal mask airway as a conduit for tracheal intubation. Results: Thirty‐four pediatric patients had an ILA placed during the course of their airway management. Eight of the 34 patients in this cohort required emergent airway management. The median age was 47.1 (0.3–202.2) months and the median weight was 16.3 (3.9–86.0) kilograms. Three of the cases were unanticipated difficult airways and the remaining were anticipated difficult airways as a result of craniofacial syndromes (n = 21), cervical spine instability or immobility (n = 7), or airway hemorrhage (n = 3). Thirty‐three of the 34 patients (97%) were intubated on the first attempt through the ILA, with the aid of a fiberoptic bronchoscope (n = 25), a Shikani Optical Stylet (n = 7), or blindly (n = 2). In one patient, blind tracheal intubation required a second attempt for successful intubation, making the overall success rate 100%. Oxygen desaturation was noted in 6 of the 34 cases. Conclusions: In a series of pediatric patients with difficult airways, the ILA was successfully used as a conduit for tracheal intubation in all patients. Visualization techniques may offer a greater degree of success in intubations through the ILA due to the potential for epiglottic down‐folding in children.     

Comparison of airway management during anaesthesia using the laryngeal mask airway CTrach and Glidescope

The design of the Laryngeal Mask Airway CTrach combines the fibreoptic viewing capability of the Glidescope and the ability for ventilation of the Fastrach. We conducted a prospective randomised trial comparing the intubation characteristics of the CTrach and Glidescope to investigate the difference in clinical performance for airway management during anaesthesia. One-hundred-and-six patients with normal airways were recruited and randomly assigned to the CTrach or Glidescope group. A standardised anaesthesia and airway management protocol was used. The time to intubation was significantly shorter for the Glidescope compared to the CTrach (43 +/- 22 vs. 73 +/- 36 s, P < 0.001). The success rates of intubation within first and three attempts were significantly higher for Glidescope. There was no apparent difference in complications of device insertion. Our results suggest that during elective management of normal airways, the time to intubation with the Glidescope is significantly shorter than the CTrach. Further studies are required to compare these devices in patients with difficult airways.     

阻塞性睡眠呼吸暂停综合征患者围术期气道管理的研究进展

阻塞性睡眠呼吸暂停综合征是一种常见的睡眠呼吸障碍疾病,其发生发展与多种因素有关。此类患者由于大多具有颈短粗、舌体肥大及口咽腔空间狭窄等异常解剖结构,会导致面罩通气以及插管困难,困难气道的发生率高。为降低此类患者围术期气道相关并发症的发生,本文就阻塞性睡眠呼吸暂停综合征患者围术期气道管理的研究进展进行综述,以期为临床提供参考。     

Four different airway-management strategies in patient with Launois-Bensaude syndrome or Madelung's disease undergoing surgical excision of neck lipomatosis with a complicated postoperative course

Launois-Bensaude syndrome, otherwise known as Madelung's disease, is a rare disorder characterized by fatty accumulations of the upper trunk, neck and head, causing serious cosmetic deformity and neck immobility. We report a case of a patient with Launois-Bensaude syndrome who required 4 different airway management strategies during his hospitalization for postoperative complications after an elective surgical excision of a severe neck lipomatosis. Anesthesiologists who treat patients with Madelung's disease should be aware of 2 major problems: difficult airway and increased frequency of postoperative bleeding. A proper choice of airway management technique is therefore necessary, including a safe intubation and extubation plan to reduce the consequences of airway complications.     

Canadian pediatric anesthesiologists prefer inhalational anesthesia to manage difficult airways: A survey

PURPOSE: To survey Canadian pediatric anesthesiologists to assess practice patterns in managing pediatric patients with difficult airways. METHODS: Canadian pediatric anesthesiologists were invited to complete a web survey. Respondents selected their preferred anesthetic and airway management techniques in six clinical scenarios. The clinical scenarios involved airway management for cases where the difficulty was in visualizing the airway, sharing the airway and accessing a compromised airway. RESULTS: General inhalational anesthesia with spontaneous respiration was the preferred technique for managing difficult intubation especially in infants (90%) and younger children (97%), however, iv anesthesia was chosen for the management of the shared airway in the older child (51%) where there was little concern regarding difficulty of intubation. Most respondents would initially attempt direct laryngoscopy for the two scenarios of anticipated difficult airway (73% and 98%). The laryngeal mask airway is commonly used to guide fibreoptic endoscopy. The potential for complete airway obstruction would encourage respondents to employ a rigid bronchoscope as an alternate technique (17% and 44%). CONCLUSION: Inhalational anesthesia remains the preferred technique for management of the difficult pediatric airway amongst Canadian pediatric anesthesiologists. Intravenous techniques are relatively more commonly chosen in cases where there is a shared airway but little concern regarding difficulty of intubation. In cases of anticipated difficult intubation, direct laryngoscopy remains the technique of choice and fibreoptic laryngoscopy makes a good alternate technique. The use of the laryngeal mask airway was preferred to facilitate fibreoptic intubation.