视频喉镜在气道管理中应用的进展

视频喉镜是能够提供上呼吸道间接视野的新型气管插管设备。在困难气道管理处理方面．与直接喉镜相比．视频喉镜能够改善声门显露的Cormack—Lehane分级,并能在较短时间内达到相同或更高的气管插管成功率。尽管视频喉镜可获得非常好的声门显露．但是应用视频喉镜时插入和推进气管导管有时可发生失败。到目前为止,尚无确切证据表明在正常或困难气道患者视频喉镜应取代直接喉镜。     

Review article: Video-laryngoscopy: another tool for difficult intubation or a new paradigm in airway management?

Background

An adequate airway management plan is essential for patient safety. Recently, new tools have been developed as alternatives to direct laryngoscopy and intubation. Among these, video-laryngoscopy has enjoyed a rapid increase in popularity and is now considered by many as the first-line technique in airway management. This paradigm shift may have an impact on patient safety.

Principal findings

Studies show that video-laryngoscopes are associated with better glottic visualization, a higher success rate for difficult airways, and a faster learning curve, resulting in a higher success rate for intubations by novice physicians. Thus, unanticipated difficult intubations may be less frequent if video-laryngoscopy is used as the first-line approach. In addition, on-screen viewing by the operator creates a new dynamic interaction during airway management. The entire operating room team can assess progress in real time, which enhances communication and improves teaching. However, if video-laryngoscopes become standard tools for tracheal intubation, these more costly devices will need to be widely available in all locations where airway management is conducted. Furthermore, algorithms for difficult intubation will require modification, and the question of selecting alternate devices will arise. If the incidence of difficult intubation decreases, the lack of motivation to teach and learn the use of alternative devices might adversely impact patient safety.

Conclusion

The greater effectiveness of video-laryngoscopes associated with multi-person visualization could enhance overall patient safety during airway management. However, the routine use of video-laryngoscopy also introduces some issues that need to be addressed to avoid potentially dangerous pitfalls.     

Management of the anticipated difficult airway—a systematic approach: Continuing Professional Development

Purpose

The purpose of this Continuing Professional Development module (CPD) is to update clinicians regarding a systematic approach for anticipated difficult airway management.

Principal findings

The focus of the approach should be directed towards providing adequate oxygenation and ventilation and not necessarily intubating the trachea. The purpose of preoperative airway assessment is not only to detect possible difficult direct laryngoscopy, but also to evaluate the probability of effective ventilation using supraglottic airway devices, such as the oropharyngeal airway or the laryngeal mask airway. Predicting the degree of difficulty with direct laryngoscopy or ventilation with a supraglottic device remains an imperfect science, and the experience of the anesthesiologist plays an important role in the clinical decision-making process. When a difficult airway is anticipated, the need for tracheal intubation should be carefully assessed. If tracheal intubation is deemed non-essential, the role of a supraglottic device should be considered. If adequate management with a supraglottic device is unlikely, then intubation is indicated with the patient awake. In certain cases, a sevoflurane induction may be chosen to test the efficacy of a supraglottic device while simultaneously maintaining spontaneous ventilation. If tracheal intubation is required, a supraglottic device may be used as a bridge during induction of anesthesia and may even be used to insert the tracheal tube. The choice of either the supraglottic device or another aid to intubation depends essentially on the anesthesiologist’s experience.

Conclusion

Airway management should be approached systematically, always keeping in mind the importance of uninterrupted oxygenation and ventilation, especially when difficulties are anticipated. Supraglottic devices can play an important role in the management of the difficult airway, whether used for the duration of surgery or inserted as an aid to intubation.     

Management of the difficult pediatric airway in an austere environment using the lightwand

Increasingly, medical teams are providing sophisticated surgical treatment to pediatric patients in developing nations. Such care is often administered under relatively austere conditions using easily transported equipment. Because some of these patients may present with congenital or acquired airway abnormalities that make direct laryngoscopy difficult or impossible, alternative methods of endotracheal intubation should be available. One such technique is lightwand-guided endotracheal intubation. Use of the lightwand has a proven record of success and obviates the need for the heavier, more delicate, and more expensive flexible fiber-optic laryngoscope or pediatric bronchoscope. Two cases are reported in which pediatric patients with difficult airway anatomy due to severe burn scar contractures were successfully and easily intubated using the lightwand. This technique is useful for management of the difficult pediatric airway in the austere environment of the typical medical relief mission.     

The difficult airway in obstetric anesthesia: Techniques for airway management and the role of regional anesthesia

A case is presented illustrating the use of a continuous spinal anesthetic in a parturient with a difficult airway who required urgent cesarean delivery. Options for endotracheal intubation of a parturient with a difficult airway are reviewed. The role of regional anesthesia in this setting is discussed. The most appropriate methods for intubation of the obstetric patient are direct laryngoscopy, the lighted stylet, and fiberoptic endoscopy. Available data suggest that regional anesthesia, specifically continuous spinal anesthesia, may be a safe and effective option for management of a parturient with a difficult airway. Further investigation of this technique is merited.     

Airway management and oxygenation in obese patients

Purpose

The purpose of this Continuing Professional Development module is to describe anatomic and physiologic challenges in obese patients, review their effects on oxygenation and airway management, and propose strategies for perioperative management.

Principal findings

The combination of excess adipose tissue deposition, increased oxygen consumption, reduced lung volumes, and increased airway resistance in obese patients increases the risk of a difficult airway and rapid oxygen desaturation in the perioperative period. Preoxygenation can be optimized by a head-up or reverse Trendelenburg position, continuous positive airway pressure, and pressure support ventilation. Difficulties in bag and mask ventilation may occur. Laryngeal exposure during direct laryngoscopy is best achieved with the patient in the “ramped” position. Tracheal tube introducers or intubating stylets can assist tracheal intubation when suboptimal laryngeal views are obtained, and video laryngoscopy may help improve the glottic view and success of tracheal intubation. New generation double-lumen supraglottic airway devices provide higher leak pressures and may be safer in obese patients, and they can also provide a conduit for bronchoscopic intubation. In patients with anticipated difficult airways, preparations should be made for awake tracheal intubation. Intraoperatively, ventilatory strategies, such as recruitment maneuvers with positive end-expiratory pressure, may reduce atelectasis and improve oxygenation. Tracheal extubation in the head-up position and continuous positive airway pressure reduce postoperative hypoxemia. Following a difficult tracheal intubation, extubation over an airway exchange catheter should be considered.

Conclusions

Rapid oxygen desaturation may occur in obese patients. Potential difficulties in airway management should be assessed and anticipated, and oxygenation, ventilation, and airway management strategies should be optimized perioperatively.     

Fiberoptic techniques

Fiberoptic intubation of the spontaneously breathing patient is the gold standard and technique of choice for the elective management of a difficult airway. In the hands of the properly trained and experienced user, it is also an excellent 'plan B' alternative when direct laryngoscopy unexpectedly fails. Fiberscope-assisted intubation through an endoscopy face mask, laryngeal mask airway or intubating laryngeal mask airway secures ventilation and oxygenation, and permits endotracheal intubation in airway emergency situations. Portable fiberscopes can be used in remote settings, increasing patient safety. This review discusses current fiberoptic intubation techniques and their applications in the management of both the anticipated and unanticipated difficult airway.     

Direct laryngoscopy and endotracheal intubation in the prone position following traumatic thoracic spine injury

Perioperative airway management in trauma victims presenting with penetrating thoracic spine injury poses a major challenge to the anesthesiologist. To avoid further neurological impairment it is essential to ensure maximal cervical and thoracic spine stability at the time of airway manipulation (e.g., direct laryngoscopy and endotracheal intubation). Airway management in the prone position additionally increases the incidence of cervical/thoracic spine injury, difficult ventilation, and difficult airway instrumentation. Although awake fiberoptic intubation of the trachea is considered the gold standard for airway instrumentation in patients with posterior thoracic/cervical trauma, this technique requires the patient's cooperation, special equipment, and extensive training, all of which might be difficult to accomplish in emergency situations. We herein present the first reported case of an adult trauma patient who underwent direct laryngoscopy and endotracheal intubation under general anesthesia in the prone position. Although the prone position is not the standard position for airway instrumentation with direct laryngoscopy and endotracheal intubation under general anesthesia, our experience indicates that this technique is possible (and relatively easy to perform) and might be considered in an emergency situation.     

Airwaymanagement: video-assisted airway management

Endotracheal intubation remains the "goldstandard" in airway management. If with use of conventional techniques intubation of the patient fails, or if an anticipated difficult airway is present, video-assisted techniques may help to increase intubation success. Video-assisted techniques give the possibility to indirectly visualise the laryngeal structures with fibreoptical or camerachip-technique, and to display the videopicture on an external or integrated monitor. For the anticipated difficult airway, awake flexible fibreoptical intubation still is the first choice. However, if Oxygenation and Ventilation can be established with bag-mask ventilation or supraglottic airways, the use of an endoscopic optical stylet or a videolaryngoscope may be alternatives. If the algorithm for the unanticipated difficult airway can be safely administered, the latter techniques may also be used as emergency intubation devices.     

Lightwand guided intubation in paediatric patients with a known difficult airway: a report of four cases

The anaesthetic management of children with craniofacial abnormalities often presents unique challenges because soft tissue and bony abnormities can affect the airway and influence airway management. We report four paediatric patients with predicted difficult airways due to craniofacial abnormalities. They all had a laryngeal view of Cormack–Lehane grade IV and were impossible to intubate using direct laryngoscopy. Fibreoptic intubation was also repeatedly attempted but was not successful. All the tracheal intubations were completed using a lightwand on the first attempt in less than 30 s. We consider that lightwand guided intubation technique may be a useful alternative approach to fibreoptic intubation technique in managing the difficult paediatric 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.     

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.     

Pourquoi une fiche d’information du patient après une intubation difficile ?

Unanticipated difficult tracheal intubation may be challenging to anaesthesiologists. It is still associated with morbidity or mortality. Previous difficult intubation is vital information to organize appropriate airway management. Unfortunately, previous studies in the literature have shown that there is poor communication of this information. We propose in this article an airway alert form, following several criteria published in the literature. This is, in our opinion, an important step to improve the efficiency of guidelines on airway management and the overall quality of the anaesthesia process. Its efficacy to decrease morbidity related to difficult tracheal intubation remains to be demonstrated.     

Infraglottic airway devices and techniques

Infraglottic airway management techniques, such as intubation of the trachea with a cuff-sealed endotracheal tube, offer significant advantages for the anaesthetized patient, especially for patients in critical condition.There are numerous ways of intubation of the trachea; the most common and popular is direct laryngoscopy. The variety of laryngoscope blades offers choices to solve difficult intubations, but all different techniques and devices need experience in routine clinical use.In case of failure, unsuccessful attempts to intubate the trachea should be limited to three, in order to use different—e.g. supraglottic or fibreoptic—techniques.Nasotracheal intubation causes an inherent risk of severe epistaxis, which may severely compromise airway management options and endangers the patient's life. Prior to passing the tube through the nose, direct laryngoscopy should be performed to estimate the Cormack–Lehane score.Rigid intubation fibrescopes—as flexible ones—do improve the view of the larynx and permit tracheal intubation with less head and cervical spine movement than direct laryngoscopy. Success with these devices requires considerable experience and clinical practice.The use of retrograde intubation has reduced during recent years, mainly due to the availability of flexible and rigid intubation fibrescopes.The EasyTube—a relatively new device—combines the advantages of both an endotracheal tube with a supraglottic airway device.The Combitube is a well-established emergency airway used widely for solving unanticipated and anticipated difficult airways. International guidelines recommend the use of Combitube following the number of studies and reports associated with its use.     

Brief report: a retrospective study of the performance of video laryngoscopy in an obstetric unit

We evaluated the performance of tracheal intubation using video laryngoscopy in an obstetric unit. We analyzed airway management details during a 3-year period, and observed 180 intubations. All cases were managed with direct or video laryngoscopy. Direct laryngoscopy resulted in 157 out of 163 (95% confidence interval [CI], 92%-99%) first attempt successful intubations and failed once. Video laryngoscopy resulted in 18 of 18 (95% CI, 81%-100%) successful intubations on first attempt. The failed direct laryngoscopy was rescued with video laryngoscopy. The patients managed with video laryngoscopy frequently required urgent or emergency surgery and had predictors of difficult direct laryngoscopy in 16 of 18 cases. Video laryngoscopy may be a useful adjunct for obstetric airway management, and its role in this difficult airway scenario should be further studied.     

Management choices for the difficult airway by anesthesiologists in Canada

PURPOSE: This study assessed difficult airway management, training and equipment availability among Canadian anesthesiologists. METHODS: A postal survey of active members of the Canadian Anesthesiologists' Society was conducted in 2000. Respondents chose an induction condition and intubation technique for each of ten difficult airway scenarios. Availability of airway devices in their workplaces was assessed. Chi square analyses were used to compare groups. A P value of < 0.05 was considered statistically significant. RESULTS: Eight hundred and thirty-three of 1702 (49%) surveys were returned. Staff comprised 88%, and residents 12%. Fifty-five percent had attended a difficult airway workshop within five years and 30% received mannequin airway training during residency. Direct laryngoscopy (48%) or fibreoptic bronchoscopy (34%) were the preferred techniques for intubation. For laryngeal, subglottic and unstable cervical spine scenarios, awake intubation with fibreoptic bronchoscope was most widely chosen. Asleep intubation with direct laryngoscopy was most commonly selected for trauma scenarios. Availability of difficult airway equipment varied between regions and types of hospital. Cricothyroidotomy equipment and difficult airway carts were not universally available. CONCLUSIONS: Our survey assessed current preferences, training and equipment availability for the difficult airway amongst Canadian anesthesiologists. Direct laryngoscopy and fibreoptic bronchoscopy were the preferred technique for intubation despite widespread availability of newer airway equipment. Lack of certain essential airway equipment and difficult airway training should be addressed.     

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。     

Management of the difficult adult airway. With special emphasis on awake tracheal intubation.

Difficulty in managing the airway is the single most important cause of major anesthesia-related morbidity and mortality. Successful management of a difficult airway begins with recognizing the potential problem. All patients should be examined for their ability to open their mouth widely and for the structures visible upon mouth opening, the size of the mandibular space, and ability to assume the sniff position. If there is a good possibility that intubation and/or ventilation by mask will be difficult, then the airway should be secured while the patient is still awake. In order for an awake intubation to be successful, it is absolutely essential that the patient be properly prepared; otherwise, the anesthesiologist will simply fulfill a self-defeating prophecy. Once the patient is properly prepared, it is likely that any one of a number of intubation techniques will be successful. If the patient is already anesthetized and/or paralyzed and intubation is found to be difficult, many repeated attempts at intubation should be avoided because progressive development of laryngeal edema and hemorrhage will develop and the ability to ventilate the lungs via mask consequently may be lost. After several attempts at intubation, it may be best to awaken the patient, do a semielective tracheostomy, or proceed with the case using mask ventilation. In the event that the ability to ventilate via mask is lost and the patient's lungs still cannot be ventilated, TTJV should be instituted immediately. Tracheal extubation of a patient with a difficult airway over a jet stylet permits a controlled, gradual, and reversible (in that ventilation and reintubation is possible at any time) withdrawal from the airway. Significant advances in the management of the difficult airway have occurred in recent years. Eighty percent of the 127 references in this article were published after 1985. However, there is much more to learn with regard to recognition of the difficult airway, preparation of the patient for an awake intubation, new techniques of endotracheal intubation, and establishment of gas exchange in patients who cannot be intubated or ventilated by mask. As the anesthesiologist's ability to manage the difficult airway significantly improves, respiratory-related morbidity and mortality will decrease.     

Tracheal intubation using suspension laryngoscopy in an infant with Goldenhar's syndrome.

We present a case of a ten-month-old boy with Goldenhar's syndrome and significant retrognathia in whom a tracheostomy was performed to relieve upper airway obstruction. Tracheal intubation was facilitated by direct suspension laryngoscopy using a slotted rigid laryngoscope. We propose this technique as an alternative method for tracheal intubation in infants and young children with a difficult airway. The management of the difficult airway in children with Goldenhar's syndrome is discussed.