Use of a tracheoscopic ventilation tube for endotracheal intubation in the difficult airway

Difficult endotracheal intubation is a clinical challenge for anesthesiologists and other practitioners of airway management. The use of a tracheoscopic ventilation tube, a novel airway device, for endotracheal intubation during general anesthesia in two patients with difficult airways after unsuccessful direct laryngoscopy is presented.     

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.     

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.     

Supraglottic airways in difficult airway management: successes, failures, use and misuse

Supraglottic airway devices (SAD) play an important role in the management of patients with difficult airways. Unlike other alternatives to standard tracheal intubation, e.g. videolaryngoscopy or intubation stylets, they enable ventilation even in patients with difficult facemask ventilation and simultaneous use as a conduit for tracheal intubation. Insertion is usually atraumatic, their use is familiar from elective anaesthesia, and compared with tracheal intubation is easier to learn for users with limited experienced in airway management. Use of SADs during difficult airway management is widely recommended in many guidelines for the operating room and in the pre-hospital setting. Despite numerous studies comparing different SADs in manikins, there are few randomised controlled trials comparing different SADs in patients with difficult airways. Therefore, most safety data come from extended use rather than high quality evidence and claims of efficacy and particularly safety must be interpreted cautiously.     

Airway management in obese patients

The well-known difficulties in airway management in obese patients are caused by obesity-related airways and respiratory changes. Anesthesiologists confront a number of troubles, including rapid oxygen desaturation, difficulty with laryngoscopy/intubation and mask ventilation, and increased susceptibility to the respiratory depressant effects of anesthetic drugs. Preoperative assessment of the airways in the obese should include examination of specific predictors of difficult mask ventilation other than those for difficult intubation. Difficulties in airway management are decreased after providing optimal preoxygenation and positioning (“ramped”). Other strategies may include availability of alternative airway management devices, including new video laryngoscopes that significantly improve the visualization of the larynx and thereby facilitate intubation. If awake intubation is mandatory, it may be performed with fibrobronchoscope after providing an adequate topical anesthesia and sedation with short-acting drugs, such as remifentanil. Succinylcholine for rapid sequence induction might be replaced by rocuronium where sugammadex is available for reversal. A complete reversal of neuromuscular block, measured by train-of-four monitoring, should be obtained before extubation, which requires a fully awake patient in the same position with airway equipment used for intubation.     

Teaching the use of fiberoptic intubation in anesthetized, spontaneously breathing patients.

In patients with difficult airways, the standard of care involves fiberoptic intubation under spontaneous ventilation. However, the safety and feasibility of a fiberoptic intubation teaching program has only been documented in paralyzed and apneic patients, whereas data obtained in patients under spontaneous respiration are limited and conflicting. We evaluated 100 anesthetized patients undergoing orotracheal fiberoptic intubation. Five anesthesia residents with no prior experience in fiberoptic laryngoscopy participated in the study. In a randomized fashion, each participant tracheally intubated 10 spontaneously breathing patients (Group A: sevoflurane anesthesia via an airway endoscopy mask) and 10 paralyzed patients (Group B: total IV anesthesia with propofol, fentanyl, atracurium). Overall rate of success (96%), defined as successful intubation of the trachea within two attempts, was not different between groups. During fiberoptic intubation, Spo2 values remained >95% in Group A, whereas Spo2 decreased to <95% in two patients in Group B. Failure to pass the tube into the trachea over the bronchoscope was encountered in four patients in Group A and in no patient in Group B. Our data suggest that it is safe to teach the use of fiberoptic intubation in anesthetized, spontaneously breathing patients with normal airway anatomy. IMPLICATIONS: Fiberoptic intubation under spontaneous respiration is a well established technique for management of difficult airways. Our study demonstrates the feasibility and safety of a novice training program for fiberoptic intubation under general anesthesia, not only in paralyzed patients but also in those breathing spontaneously.     

Translaryngeal guided intubation solved a critical airway problem

Airway obstruction during the induction of general anesthesia remains a persistent problem in modern anesthesia practice, particularly in obstetric patients. Generally, a careful preoperative airway evaluation uncovers most abnormalities that might make intubation difficult. The planning and preparation for additional intubation equipment facilitate an anticipated difficult intubation. However, situations may arise in which unanticipated airway obstruction occurs requiring prompt management. Although every anesthesia provider is trained to manage such acute airway problems, the provision of a patent airway is not always possible, particularly when repeated attempts at endoscopic or blind intubation have failed, leaving a bloody field that prevents optimal visualization, or when time does not allow to wake up the patient. In this article a difficult airway problem is reported in which translaryngeal guided intubation was lifesaving.     

A universally applicable mask attachment for fiberoptic intubation. The Mainz Universal Adapter

The problems associated with "difficult airways" have almost subsided since the introduction of flexible fiberoptic bronchoscopes for tracheal intubation. Limitations of this technique persist with uncooperative patients, children and infants. We describe an universally applicable connector for fiberoptic intubation during mask ventilation, which fits all masks with a 22-mm connector, including the Rendell-Baker-Soucek type. This technique is of utmost value when a "difficult airway" is encountered only subsequent to induction of anesthesia, especially if nondepolarizing muscle relaxants have been administered. The device makes intubation possible with all sizes of fiberoptic bronchoscopes. The prerequisites for application of this technique include an airway that will be maintained by mask ventilation.     

Intubation via LMA in pediatric patients with difficult airways

PURPOSE: To report two cases of successful tracheal intubation in difficult pediatric airways using a conventional laryngeal mask airway (LMA) with an extended polyvinyl chloride (PVC) tube after laryngeal assessment with a fibreoptic device. CLINICAL FEATURES: Two cases, Dandy-Walker and Pierre Robin syndromes, were scheduled for surgery. They were premedicated with 0.5 mg x kg(-1) promethazine p.o. 90 min before surgery. Both patients arrived in the operating room sedated, with dry mouth, and without evidence of increased intracranial tension or airway obstruction. Inhalational induction with isoflurane 0.5-3% was commenced. Conventional tracheal intubation was impossible in both cases. In each an LMA was inserted to maintain ventilation, anesthesia, and to facilitate intubation. Fibreoptic bronchoscopy was used to assess the larynx, followed by blind intubation via the LMA using extended PVC tracheal tube (TT). Anesthesia was maintained during intubation using Mapleson F anesthesia circuit attached to a connector with fibreoptic bronchoscope adapter. CONCLUSION: This report describes the assessment of the airway with fibreoptic bronchoscopy after LMA insertion facilitated blind tracheal intubation in two children with difficult airways.     

Cannot intubate, cannot ventilate: airway management of difficult airways in adults

Cannot intubate, cannot ventilate (CICV) is one major cause of death associated with general anesthesia and thus proper airway management plans are necessary. To achieve safe airway management, it is necessary first to predict if the patient's trachea can be difficult to intubate or the lungs difficult to ventilate. When difficulty is predicted, the following factors should be considered: (1) if general anesthesia is truly necessary; (2) if tracheal intubation is mandatory; (3) if muscle relaxation is required; (4) if awake intubation is safer; (5) if surgical airway is required; and (6) if tracheal intubation can prevent airway obstruction. When CICV occurred after general anesthesia, it is important to remember that the primary task is to oxygenate the patient, and not to intubate the trachea: the patient may need to be awaken, surgical airway obtained, or cardiopulmonary bypass established. To make a right decision, it is necessary to know the advantages and disadvantages of each option, as well as of each airway device, and to be acquainted with these devices during routine anesthesia. In this article, I will present six typical cases of difficult airways, and will discuss appropriate options for safer airway management.     

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.     

声门上通气装置引导气管插管的临床应用进展

声门上通气装置（SAD）在院前急救、常规麻醉及困难气道的开放、维持氧合等方面发挥着重要作用,同时也为引导气管插管提供了一个可行方式。在日常麻醉及手术室外治疗或抢救中,保持气道通畅和充分氧合是气道管理的关键。困难插管发生率约4.5%～7.5%,困难气道管理仍是麻醉管理中的重中之重。在困难插管发生时,先可放置SAD,后经SAD盲探或在可视设备辅助下行气管插管,迅速建立气道、提高首次插管成功率、减少插管过程中气道损伤。本文着重介绍不同种类可引导气管插管的SAD的临床应用进展。     

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.     

A retrospective audit of anesthetic techniques and complications in children with mucopolysaccharidoses

Objectives and aims:  To document the incidence of difficult airway management and difficult intubation in the era of replacement therapy for Australian children with mucopolysaccharidosis (MPS). Background:  Medical treatment for MPS has developed significantly since 1980’s with a large number of patients now being offered either bone marrow transplant or enzyme replacement. The impact of these therapies on the incidence of difficult airway management has not been adequately documented. Similarly, anesthesia techniques and airway devices have been developed, which are thought to have greatly increased the safety of managing these patients under anesthesia but their role in children with MPS has not been systematically described. Methods:  A retrospective chart review of 17 patients with MPS who had received anesthetics at the Royal Children’s Hospital during the time frame January 1998–January 2011. The primary outcome was the incidence of difficult or failed intubation. Secondary outcomes were the relationship between the incidence of difficult intubation and treatment with enzyme replacement therapy (ERT) or bone marrow transplantation. Results:  Seventeen patients received 141 anesthetics for 214 procedures. Difficult face mask ventilation occurred in 20 anesthetics (14.2%). Difficult intubation occurred in 40 anesthetics (25%). Failed intubation occurred in two cases (1.6%).The incidence of difficult intubation was 12% in MPS I, 35% MPS II, 86.7% in MPS VI, and 0% in MPS III and IV. Conclusions:  Hematopoietic stem cell transplantation prior to 2 years of age reduces the incidence of difficult mask ventilation and difficult intubation in children with MPS I. ERT was initiated late in the clinical course of MPS II and VI and induced improvements in upper airway patency but did not reduce the incidence of difficult airway management.     

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.     

Fiberoptic intubation through laryngeal mask airway with an innovated tube under 5% sevoflurane anesthesia

BACKGROUND : Previously we had reported an intubation method using 52 cm innovated tube (I. D.=5.0) for patients with difficult airways, but hemodynamic change and anesthetic level were not evaluated during this procedure. In the present report we investigated heart rate, mean arterial pressure and bispectral index (BIS) during this procedure under volatile induction and maintainance of anesthesia (VIMA) with 5% sevoflurane without muscle relaxant. METHODS : We enrolled 6 patients considered having difficult airway. Airway management was performed under VIMA of 5% sevoflurane. After insertion of a laryngealmask airway (LMA), 52 cm-tube was intubated through LMA under bronchofiberscope. After LMA was removed, the endotracheal tube was passed through the 52 cm-tube into the trachea. Hemodynamic change was recorded at 1 min intervals and BIS at 5 sec intervals until 3 min after securing their airways. RESULTS : VIMA of 5% sevoflurane provides stable hemodynamic state during the procedure and suppressed body movement sufficiently on tracheal intubation. BIS was elevated due to cough on intubation in 4 cases. However no patient recalled the procedure. CONCLUSIONS : Sevoflurane 5% suppressed hemodynamic changes sufficiently with this procedure without muscle relaxants.     

Unanticipated difficult airway in anesthetized patients: prospective validation of a management algorithm

BACKGROUND: Management strategies conceived to improve patient safety in anesthesia have rarely been assessed prospectively. The authors undertook a prospective evaluation of a predefined algorithm for unanticipated difficult airway management. METHODS: After a 2-month period of training in airway management, 41 anesthesiologists were asked to follow a predefined algorithm for management in the case of an unanticipated difficult airway. Two different scenarios were distinguished: "cannot intubate" and "cannot ventilate." The gum elastic bougie and the Intubating Laryngeal Mask Airway (ILMA) were proposed as the first and second steps in the case of impossible laryngoscope-assisted tracheal intubation, respectively. In the case of impossible ventilation or difficult ventilation, the IMLA was recommended, followed by percutaneous transtracheal jet ventilation. The patient's details, adherence rate to the algorithm, efficacy, and complications of airway management processes were recorded. RESULTS: Impossible ventilation never occurred during the 18-month study. One hundred cases of unexpected difficult airway were recorded (0.9%) among 11,257 intubations. Deviation from the algorithm was recorded in three cases, and two patients were wakened before any alternative intubation technique attempt. All remaining patients were successfully ventilated with either the facemask (89 of 95) or the ILMA (6 of 95). Six difficult-ventilation patients required the ILMA before completion of the first intubation step. Eighty patients were intubated with the gum elastic bougie, and 13 required a blind intubation through the ILMA. Two patients ventilated with the ILMA were never intubated. CONCLUSION: When applied in accordance with a predefined algorithm, the gum elastic bougie and the ILMA are effective to solve most problems occurring during unexpected difficult airway management.     

人工智能在气道管理中的应用

人工智能技术的发展促进了气道管理方法和设备的更新,具有优化、解决气道管理中延迟插管、气道困难和气管导管位置的评估等问题的潜力。本文总结了气道管理领域常用的人工智能模型,从患者气管插管需求的预测、困难气道患者的识别、气管导管定位、气管插管设备的自动化和智能化进行总结阐述,为围术期气道管理工作提供参考。     

Incidence of unanticipated difficult airway in obstetric patients in a teaching institution

Purpose

Our aim was to determine the incidence of difficult intubation during pregnancy-related surgery at a high-risk, high-volume teaching institution.

Methods

Airway experience was analyzed among patients who had pregnancy-related surgery under general anesthesia from January 2001 through February 2006. A difficult airway was defined as needing three or more direct laryngoscopy (DL) attempts, use of the additional airway equipment after the DL attempts, or conversion to regional anesthesia due to inability to intubate. Airway characteristics were compared between patients with and without a difficult airway. In addition, pre- and postoperative airway evaluations were compared to identify factors closely related to changes from pregnancy.

Results

In a total of 30,766 operations, 2,158 (7%) were performed with general anesthesia. Among these, 1,026 (47.5%) were for emergency cesarean delivery (CD), 610 (28.3%) for nonemergency CD, and 522 (24.2%) for non-CD procedures. A total of 12 patients (0.56%) were identified as having a difficult airway. Four patients were intubated with further DL attempts; others required mask ventilation and other airway equipment. Two patients were ventilated through a laryngeal mask airway without further intubation attempts. Ten of the 12 difficult airway cases were encountered by residents during their first year of clinical anesthesia training. There were no maternal or fetal complications except one possible aspiration.

Conclusion

Unanticipated difficult airways accounted for 0.56% of all pregnancy-related surgical patients. More than 99.9% of all obstetric patients could be intubated. A difficult airway is more likely to be encountered by anesthesia providers with <1?year of experience. Proper use of airway equipment may help secure the obstetric airway or provide adequate ventilation. Emergency CD did not add an additional level of difficulty over nonemergency CD.     

声门上气道装置口咽部漏气压影响因素的研究进展

自引入喉罩（LMA）以来,声门上气道装置（SAD）便在临床麻醉实践中不断发展,逐渐成为传统气管插管的良好替代方案。SAD最初主要用于手术室麻醉气道管理,目前越来越多地用于多种场合快速、安全、有效地建立气道,或作为困难气道的紧急通气设备。对于不同类型SAD性能的客观比较主要通过口咽部漏气压（OLP）,OLP越高意味着气道的密闭性越好。围术期有多种因素对OLP造成影响,进而影响机械通气的安全性和有效性。本文对OLP影响因素的最新研究进展进行综述,以期为更好的气道管理提供参考依据。