Abstract

These guidelines provide a strategy to manage unanticipated difficulty with tracheal intubation. They are founded on published evidence. Where evidence is lacking, they have been directed by feedback from members of the Difficult Airway Society and based on expert opinion. These guidelines have been informed by advances in the understanding of crisis management; they emphasize the recognition and declaration of difficulty during airway management. A simplified, single algorithm now covers unanticipated difficulties in both routine intubation and rapid sequence induction. Planning for failed intubation should form part of the pre-induction briefing, particularly for urgent surgery. Emphasis is placed on assessment, preparation, positioning, preoxygenation, maintenance of oxygenation, and minimizing trauma from airway interventions. It is recommended that the number of airway interventions are limited, and blind techniques using a bougie or through supraglottic airway devices have been superseded by video- or fibre-optically guided intubation. If tracheal intubation fails, supraglottic airway devices are recommended to provide a route for oxygenation while reviewing how to proceed. Second-generation devices have advantages and are recommended. When both tracheal intubation and supraglottic airway device insertion have failed, waking the patient is the default option. If at this stage, face-mask oxygenation is impossible in the presence of muscle relaxation, cricothyroidotomy should follow immediately. Scalpel cricothyroidotomy is recommended as the preferred rescue technique and should be practised by all anaesthetists. The plans outlined are designed to be simple and easy to follow. They should be regularly rehearsed and made familiar to the whole theatre team.

Clinical practice has changed since the publication of the original Difficult Airway Society (DAS) guidelines for management of unanticipated difficult intubation in 2004.1 The 4th National Audit Project of the Royal College of Anaesthetists and Difficult Airway Society (NAP4) provided detailed information about the factors contributing to poor outcomes associated with airway management and highlighted deficiencies relating to judgement, communication, planning, equipment, and training.2 New pharmacological agents and videolaryngoscopes have been introduced, and further research has focused on extending the duration of apnoea without desaturation by improving preoxygenation and optimizing patient position.

These updated guidelines provide a sequential series of plans to be used when tracheal intubation fails and are designed to prioritize oxygenation while limiting the number of airway interventions in order to minimize trauma and complications (Fig 1). The principle that anaesthetists should have back-up plans in place before performing primary techniques still holds true.

Separate guidelines exist for difficult intubation in paediatric anaesthesia, obstetric anaesthesia, and for extubation.3–5

These guidelines are directed at the unanticipated difficult intubation. Every patient should have an airway assessment performed before surgery to evaluate all aspects of airway management, including front-of-neck access.

Fig 1

Difficult Airway Society difficult intubation guidelines: overview. Difficult Airway Society, 2015, by permission of the Difficult Airway Society. This image is not covered by the terms of the Creative Commons Licence of this publication. For permission to re-use, please contact the Difficult Airway Society. CICO, can't intubate can't oxygenate; SAD, supraglottic airway device.

Fig 1

Difficult Airway Society difficult intubation guidelines: overview. Difficult Airway Society, 2015, by permission of the Difficult Airway Society. This image is not covered by the terms of the Creative Commons Licence of this publication. For permission to re-use, please contact the Difficult Airway Society. CICO, can't intubate can't oxygenate; SAD, supraglottic airway device.

The aim of the guidelines is to provide a structured response to a potentially life-threatening clinical problem. They take into account current practice and recent developments.

Every adverse event is unique, the outcome of which will be influenced by patient co-morbidity, urgency of the procedure, skill set of the anaesthetist, and available resources.2,6 It is acknowledged that anaesthetists do not work in isolation and that the role of the anaesthetic assistant is important in influencing the outcome of an airway crisis.7 Decisions about the best alternatives in the event of difficulty should be made and discussed with the anaesthetic assistant before induction of anaesthesia.

These guidelines recognize the difficulties in decision-making during an unfolding emergency. They include steps to assist the anaesthetic team in making the correct decisions, limiting the number of airway intervention attempts, encouraging declaration of failure by placing a supraglottic airway device (SAD) even when face-mask ventilation is possible, and explicitly recommending a time to stop and think about how to proceed.

An attempt has been made to identify essential skills and techniques with the highest success rate. Anaesthetists and anaesthetic assistants using these guidelines must ensure that they are familiar with the equipment and techniques described. This may require acquisition of new skills and regular practice, even for experienced anaesthetists.

Methods

The Difficult Airway Society commissioned a working group to update the guidelines in April 2012. An initial literature search was conducted for the period January 2002 to June 2012 using databases (Medline, PubMed, Embase, and Ovid) and a search engine (Google Scholar). The websites of the American Society of Anesthesiologists (http://www.asahq.org), Australian and New Zealand College of Anaesthetists (http://www.anzca.edu.au), European Society of Anesthesiologists' (http://www.esahq.org/euroanaesthesia), Canadian Anesthesiologists' Society (http://www.cas.ca), and the Scandinavian Society of Anesthesiology and Intensive Care Medicine (http://ssai.info/guidelines/) were also searched for airway guidelines. English language articles and abstract publications were identified using keywords and filters. The search terms were as follows: ‘Aintree intubating catheter’, ‘Airtraq’, ‘airway device’, ‘airway emergency’, ‘airway management’, ‘Ambu aScope’, ‘backward upward rightward pressure’, ‘Bonfils’, ‘Bullard’, ‘bronchoscopy’, ‘BURP manoeuvre’, ‘can't intubate can't ventilate’, ‘can't intubate can't oxygenate’, ‘C-Mac’, ‘Combitube’, ‘cricoid pressure’, ‘cricothyroidotomy’, ‘cricothyrotomy’, ‘C trach’, ‘difficult airway’, ‘difficult intubation’, ‘difficult laryngoscopy’, ‘difficult mask ventilation’, ‘difficult ventilation’, ‘endotracheal intubation’, ‘esophageal intubation’, ‘Eschmann stylet’, ‘failed intubation’, ‘Fastrach’, ‘fiber-optic scope’, ‘fibreoptic intubation’, ‘fiberoptic scope’, ‘fibreoptic stylet’, ‘fibrescope’ ‘Frova catheter', ‘Glidescope’, ‘gum elastic bougie’, ‘hypoxia’, ‘i-gel’, ‘illuminating stylet’, ‘jet ventilation catheter’, ‘laryngeal mask’, ‘laryngeal mask airway Supreme’, ‘laryngoscopy’, ‘lighted stylet’, ‘light wand’, ‘LMA Supreme’, ‘Manujet’, ‘McCoy’, ‘McGrath’, ‘nasotracheal intubation’, ‘obesity’, ‘oesophageal detector device’, ‘oesophageal intubation’, ‘Pentax airway scope’, ‘Pentax AWS’, ‘ProSeal LMA′, ‘Quicktrach’, ‘ramping’, ‘rapid sequence induction’, ‘Ravussin cannula’, ‘Sanders injector’, ‘Shikani stylet’, ‘sugammadex’, ‘supraglottic airway’, ‘suxamethonium’, ‘tracheal introducer’, ‘tracheal intubation’, ‘Trachview’, ‘Tru view’, ‘tube introducer’, ‘Venner APA’, ‘videolaryngoscope’, and ‘videolaryngoscopy’.

The initial search retrieved 16 590 abstracts. The searches (using the same terms) were repeated every 6 months. In total, 23 039 abstracts were retrieved and assessed for relevance by the working group; 971 full-text articles were reviewed. Additional articles were retrieved by cross-referencing the data and hand-searching. Each of the relevant articles was reviewed by at least two members of the working group. In areas where the evidence was insufficient to recommend particular techniques, expert opinion was sought and reviewed.8 This was most notably the situation when reviewing rescue techniques for the ‘can't intubate can't oxygenate’ (CICO) situation.

Opinions of the DAS membership were sought throughout the process. Presentations were given at the 2013 and 2014 DAS Annual Scientific meetings, updates were posted on the DAS website, and members were invited to complete an online survey about which areas of the existing guidelines needed updating. Following the methodology used for the extubation guidelines,5 a draft version of the guidelines was circulated to selected members of DAS and acknowledged international experts for comment. All correspondence was reviewed by the working group.

Disclaimer

It is not intended that these guidelines should constitute a minimum standard of practice, nor are they to be regarded as a substitute for good clinical judgement.

Human factors

Human factors issues were considered to have contributed to adverse outcomes in 40% of the instances reported to NAP4; however, a more in-depth analysis of a subset of patients identified human factor influences in every instance. Flin and colleagues9 identified latent threats (poor communication, poor training and teamwork, deficiencies in equipment, and inadequate systems and processes) predisposing to loss of situation awareness and subsequent poor decision-making as a precursor to final action errors.

Adoption of guidelines and a professional willingness to follow them are not enough on their own to avoid serious complications of airway management during anaesthesia. All the instances reported to NAP4 occurred despite widespread dissemination of the original DAS guidelines, which had been published in 2004. The complexities of difficult airway management cannot be distilled into a single algorithm, and even the best anaesthetic teams supported by the best guidelines will still struggle to perform optimally if the systems in which they operate are flawed.10 The 2015 guidelines acknowledge this.

During a crisis, it is common to be presented with more information than can be processed.11 This cognitive overload impairs decision-making and can cause clinicians to ‘lose sight of the big picture’ and become fixated on a particular task, such as tracheal intubation or SAD placement. These guidelines provide an explicit instruction for the team to ‘stop and think’ to help reduce this risk.

Poor anaesthetic decision-making secondary to cognitive errors and the impact of human factors in emergency airway management has recently been discussed.12 Cognitive aids are increasingly being used by clinicians during unfolding emergencies;13 for example, the Vortex Approach has been devised to support decision-making during difficult airway management.14 The algorithms that accompany these guidelines are intended as teaching and learning tools and have not been specifically designed to be used as prompts during an airway crisis.

For any plan to work well in an emergency, it must be known to all members of the team and should be rehearsed. For rare events, such as CICO, this rehearsal can be achieved with simulation training, as has recently been included in the Australian and New Zealand College of Anaesthetists continuing professional development requirements.15,16 This also provides the opportunity to develop non-technical skills, such as leadership, team coordination, communication, and shared understanding of roles, which has been shown to improve performance in intensive care and trauma teams.17,18

Structured communication between anaesthetists and anaesthetic assistants could help prepare for and deal with airway difficulties. Talking before every patient, or at least before every list, about the plan to manage difficulties should they develop is good practice. At a minimum, this involves thinking about the challenges that might be encountered and checking that the appropriate equipment is available.

If airway management does become difficult after induction of anaesthesia, a clear declaration of failure at the end of each plan will facilitate progression through the airway strategy. The use of a structured communication tool, such as PACE (Probe, Alert, Challenge, Emergency), can aid communication of concerns when cognitive overload and hierarchical barriers might otherwise make this difficult.19

Our profession must continue to acknowledge and address the impact of environmental, technical, psychological, and physiological factors on our performance. Human factors issues at individual, team, and organizational levels all need to be considered to enable these 2015 guidelines to be as effective as possible.

Preoperative assessment and planning

Airway management is safest when potential problems are identified before surgery, enabling the adoption of a strategy, a series of plans, aimed at reducing the risk of complications.2

Preoperative airway assessment should be performed routinely in order to identify factors that might lead to difficulty with face-mask ventilation, SAD insertion, tracheal intubation, or front-of-neck access.

Prediction of difficulty in airway management is not completely reliable;20–22 the anaesthetist should have a strategy in place before the induction of anaesthesia, and this should be discussed at the team brief and the sign-in (pre-induction) phase of the WHO Surgical Safety Checklist.23,24

Assessment of the risk of aspiration is a key component of planning airway management. Steps should be taken before surgery to reduce the volume and pH of gastric contents by fasting and pharmacological means. Mechanical drainage by nasogastric tube should be considered in order to reduce residual gastric volume in patients with severely delayed gastric emptying or intestinal obstruction.2

Rapid sequence induction

The placement of a cuffed tube in the trachea offers the greatest protection against aspiration. Suxamethonium is the traditional neuromuscular blocking agent of choice because its rapid onset allows early intubation without the need for bag–mask ventilation. Several studies have compared suxamethonium with rocuronium for rapid sequence induction, and although some have shown better intubating conditions with suxamethonium, others have found that after rocuronium 1.2 mg kg−1 the speed of onset and intubation conditions are comparable.25–30 Suxamethonium-induced fasciculation increases oxygen consumption during apnoea, which may become relevant in the event of airway obstruction.31,32 The ability to antagonize the effect of rocuronium rapidly with sugammadex may be an advantage,30 although it should be remembered that this does not guarantee airway patency or the return of spontaneous ventilation.33,34 If rapid antagonism of rocuronium with sugammadex is part of the failed intubation plan, the correct dose (16 mg kg−1) must be immediately available.35,36

Cricoid pressure is applied to protect the airway from contamination during the period between loss of consciousness and placement of a cuffed tracheal tube. This is a standard component of a rapid sequence induction in the UK.37 It is often overlooked that cricoid pressure has been shown to prevent gastric distension during mask ventilation and was originally described for this purpose.38,39 Gentle mask ventilation after the application of cricoid pressure and before tracheal intubation prolongs the time to desaturation. This is most useful in those with poor respiratory reserve, sepsis, or high metabolic requirements and also provides an early indication of the ease of ventilation. A force of 30 N provides good airway protection, while minimizing the risk of airway obstruction, but this is not well tolerated by the conscious patient.40

Cricoid pressure should be applied with a force of 10 N when the patient is awake, increasing to 30 N as consciousness is lost.41,42 Although the application of cricoid pressure creates a physical barrier to the passage of gastric contents, it has also been shown to reduce lower oesophageal sphincter tone, possibly making regurgitation more likely.43,44 Current evidence suggests that if applied correctly, cricoid pressure may improve the view on direct laryngoscopy.45 However, there are many reports demonstrating that it is often poorly applied, and this may make mask ventilation, direct laryngoscopy, or SAD insertion more difficult.46–52 If initial attempts at laryngoscopy are difficult during rapid sequence induction, cricoid pressure should be released. This should be done under vision with the laryngoscope in place and suction available; in the event of regurgitation,41 cricoid pressure should be immediately reapplied.

Second-generation SADs offer greater protection against aspiration than first-generation devices and are recommended should intubation fail during a rapid sequence induction.

Plan A. Mask ventilation and tracheal intubation

The essence of Plan A (Table 1) is to maximize the likelihood of successful intubation at the first attempt or, failing that, to limit the number and duration of attempts at laryngoscopy in order to prevent airway trauma and progression to a CICO situation.

Table 1

Key features of Plan A

  • Maintenance of oxygenation is the priority

  • Advantages of head-up positioning and ramping are highlighted

  • Preoxygenation is recommended for all patients

  • Apnoeic oxygenation techniques are recommended in high-risk patients

  • The importance of neuromuscular block is emphasized

  • The role of videolaryngoscopy in difficult intubation is recognized

  • All anaesthetists should be skilled in the use of a videolaryngoscope

  • A maximum of three attempts at laryngoscopy are recommended (3+1)

  • Cricoid pressure should be removed if intubation is difficult

 
  • Maintenance of oxygenation is the priority

  • Advantages of head-up positioning and ramping are highlighted

  • Preoxygenation is recommended for all patients

  • Apnoeic oxygenation techniques are recommended in high-risk patients

  • The importance of neuromuscular block is emphasized

  • The role of videolaryngoscopy in difficult intubation is recognized

  • All anaesthetists should be skilled in the use of a videolaryngoscope

  • A maximum of three attempts at laryngoscopy are recommended (3+1)

  • Cricoid pressure should be removed if intubation is difficult

 

All patients should be optimally positioned and preoxygenated before induction of anaesthesia. Neuromuscular block facilitates face-mask ventilation53,54 and tracheal intubation. Every attempt at laryngoscopy and tracheal intubation has the potential to cause trauma. A suboptimal attempt is a wasted attempt and having failed, the chance of success declines with each subsequent attempt.55,56 Repeated attempts at tracheal intubation may reduce the likelihood of effective airway rescue with a SAD.57 These guidelines recommend a maximum of three attempts at intubation; a fourth attempt by a more experienced colleague is permissible. If unsuccessful, a failed intubation should be declared and Plan B implemented.

Position

Good patient positioning maximizes the chance of successful laryngoscopy and tracheal intubation. In most patients, the best position for direct laryngoscopy with a Macintosh-style blade is achieved with the neck flexed and the head extended at the atlanto-occipital joint; the classic ‘sniffing’ position.58–60 In the obese patient, the ‘ramped’ position should be used routinely to ensure horizontal alignment of the external auditory meatus and the suprasternal notch because this improves the view during direct laryngoscopy.61–64 This position also improves airway patency and respiratory mechanics and facilitates passive oxygenation during apnoea.65,66

Preoxygenation and apnoeic techniques to maintain oxygenation

All patients should be preoxygenated before the induction of general anaesthesia.67 De-nitrogenation can be achieved with an appropriate flow of 100% oxygen into the breathing system, maintaining an effective face-mask seal68 until the end-tidal oxygen fraction is 0.87–0.9.69 Many other preoxygenation techniques have been described.70–79

Preoxygenation increases the oxygen reserve, delays the onset of hypoxia, and allows more time for laryngoscopy, tracheal intubation,65,69 and for airway rescue should intubation fail. In healthy adults, the duration of apnoea without desaturation (defined as the interval between the onset of apnoea and the time peripheral capillary oxygen saturation reaches a value of ≤90%) is limited to 1–2 min whilst breathing room air, but can be extended to 8 min with preoxygenation.69 Preoxygenation using a 20–25° head-up position80,81 and continuous positive airway pressure has been shown to delay the onset of hypoxia in obese patients.82–84 The duration of apnoea without desaturation can also be prolonged by passive oxygenation during the apnoeic period (apnoeic oxygenation). This can be achieved by delivering up to 15 litres min−1 of oxygen through nasal cannulae, although this may be uncomfortable for an awake patient.65,85,86 Nasal Oxygenation During Efforts Of Securing A Tube (NODESAT) has been shown to extend the apnoea time in obese patients and in patients with a difficult airway.87 Transnasal humidified high-flow oxygen (up to 70 litres min−1) via purpose-made nasal cannulae has been shown to extend the apnoea time in obese patients and in patients with difficult airways,88 although it's efficacy as a means of preoxygenation has not been evaluated fully.89,90 Apnoeic oxygenation is an area of recent research interest about which further evidence is awaited. The administration of oxygen by nasal cannulae in addition to standard preoxygenation and face-mask ventilation is recommended in high-risk patients.

Choice of induction agent

The induction agent should be selected according to the clinical condition of the patient. Propofol, the most commonly used induction agent in the UK, suppresses laryngeal reflexes and provides better conditions for airway management than other agents.91–93

The 5th National Audit Project of the Royal College of Anaesthetists highlighted the relationship between difficult airway management and awareness.94 It is important to ensure that the patient is adequately anaesthetized during repeated attempts at intubation.

Neuromuscular block

If intubation is difficult, further attempts should not proceed without full neuromuscular block. Neuromuscular block abolishes laryngeal reflexes, increases chest compliance, and facilitates face-mask ventilation.53,54,95 Complete neuromuscular block should be ensured if any difficulty is encountered with airway management.96 Rocuronium has a rapid onset and can be antagonized immediately with sugammadex, although the incidence of anaphylaxis may be higher than with other non-depolarizing neuromuscular blocking agents.97–99

Mask ventilation

Mask ventilation with 100% oxygen should begin as soon as possible after induction of anaesthesia. If difficulty is encountered, the airway position should be optimized and airway manoeuvres such as a chin lift or jaw thrust should be attempted. Oral and nasopharyngeal airways should be considered, and a four-handed technique (two-person or pressure-controlled mechanical ventilation) should be used.100 The ‘sniffing’ position increases the pharyngeal space and improves mask ventilation.101 Inadequate anaesthesia or inadequate neuromuscular block make mask ventilation more difficult.102,103

Choice of laryngoscope

The choice of laryngoscope influences the chance of successful tracheal intubation. Videolaryngoscopes offer an improved view compared with conventional direct laryngoscopy and are now the first choice or default device for some anaesthetists.104–113 Regular practice is required to ensure that the improved view translates reliably into successful tracheal intubation.114 All anaesthetists should be trained to use, and have immediate access to, a videolaryngoscope.115 The flexible fibrescope or optical stylets, such as Bonfils (Karl Storz), Shikani (Clarus Medical), or Levitan FPS scope™ (Clarus Medical), may be the preferred choice for individuals who are expert in their use.116–122 The first and second choice of laryngoscope will be determined by the anaesthetist's experience and training.

Tracheal tube selection

Tracheal tubes should be selected according to the nature of the surgical procedure, but their characteristics can influence the ease of intubation. A smaller tube is easier to insert because a better view of the laryngeal inlet is maintained during passage of the tube between the cords. Smaller tubes are also less likely to cause trauma.123 ‘Hold-up’ at the arytenoids is a feature of the left-facing bevel of most tracheal tubes, and can occur particularly whilst railroading larger tubes over a bougie, stylet, or fibrescope.124,125 This problem can be overcome by rotating the tube anticlockwise to change the orientation of the bevel or by preloading the tube so that the bevel faces posteriorly and by minimizing the gap between the fibrescope and the tube during fibre-optic intubation.125–127 Tubes with hooded, blunted, or flexible tips, such as the Parker Flex-Tip™ (Parker Medical), and tubes supplied with the Intubating LMA® (Teleflex Medical Europe Ltd) have been designed to reduce the incidence of this problem.128–132

Laryngoscopy

In these guidelines, an attempt at laryngoscopy is defined as the insertion of a laryngoscope into the oral cavity. Every attempt should be carried out with optimal conditions because repeated attempts at laryngoscopy and airway instrumentation are associated with poor outcomes and the risk of developing a CICO situation.56,133–136 If difficulty is encountered, help should be summoned early, regardless of the level of experience of the anaesthetist.

If intubation is difficult, there is little point in repeating the same procedure unless something can be changed to improve the chance of success. This may include the patient's position, the intubating device or blade, adjuncts such as introducers and stylets, depth of neuromuscular block, and personnel. The number of attempts at laryngoscopy should be limited to three. A fourth attempt should be undertaken only by a more experienced colleague.

External laryngeal manipulation

External laryngeal manipulation applied with the anaesthetist's right hand or backward, upward, and rightward pressure (BURP) on the thyroid cartilage applied by an assistant may improve the view at laryngoscopy.137–142 A benefit of videolaryngoscopy is that the anaesthetic assistant is also able to see the effects of laryngeal manipulation.143

Use of a bougie or stylet

The gum elastic bougie is a widely used device for facilitating tracheal intubation when a grade 2 or 3a view of the larynx is seen during direct laryngoscopy.144–146 Pre-shaping of the bougie facilitates successful intubation.147 It can also be helpful during videolaryngoscopy.148,149 Blind bougie insertion is associated with trauma and is not recommended in a grade 3b or 4 view.150–155 The ‘hold-up’ sign may signal the passage of the bougie as far as small bronchi,156 but it is associated with risk of airway perforation and trauma, especially with single-use bougies.153,157–159 Forces as little as 0.8 N can cause airway trauma.153 The characteristics of bougies vary, and this may affect their performance.153 Once the bougie is in the trachea, keeping the laryngoscope in place enhances the chance of successful intubation.129 Non-channelled videolaryngoscopes with angulated blades necessitate the use of a pre-shaped stylet or bougie to aid the passage of the tracheal tube through the cords.160–163 When using a videolaryngoscope, the tip of the tube should be introduced into the oropharynx under direct vision because failure to do so has been associated with airway trauma.163–167

Tracheal intubation and confirmation

Difficulty with tracheal intubation is usually the result of a poor laryngeal view, but other factors, such as tube impingement, can hinder the passage of the tube into the trachea.

Once tracheal intubation has been achieved, correct placement of the tube within the trachea must be confirmed. This should include visual confirmation that the tube is between the vocal cords, bilateral chest expansion, and auscultation and capnography. A continuous capnography waveform with appropriate inspired and end-tidal values of CO2 is the gold standard for confirming ventilation of the lungs. Capnography should be available in every location where a patient may require anaesthesia.2,168

Absence of exhaled CO2 indicates failure to ventilate the lungs, which may be a result of oesophageal intubation or complete airway obstruction (rarely, complete bronchospasm).2 In such situations, it is safest to assume oesophageal intubation. Videolaryngoscopy, examination with a fibrescope, or ultrasound can be used to verify that the tube is correctly positioned.169–171

Fig 2

Management of unanticipated difficult tracheal intubation in adults. Difficult Airway Society, 2015, by permission of the Difficult Airway Society. This image is not covered by the terms of the Creative Commons Licence of this publication. For permission to re-use, please contact the Difficult Airway Society. SAD, supraglottic airway device.

Fig 2

Management of unanticipated difficult tracheal intubation in adults. Difficult Airway Society, 2015, by permission of the Difficult Airway Society. This image is not covered by the terms of the Creative Commons Licence of this publication. For permission to re-use, please contact the Difficult Airway Society. SAD, supraglottic airway device.

Plan B. Maintaining oxygenation: supraglottic airway device insertion

In these guidelines (Fig. 2), the emphasis of Plan B (Table 2) is on maintaining oxygenation using an SAD.

Table 2

Key features of Plan B. SAD, supraglottic airway device

  • Failed intubation should be declared

  • The emphasis is on oxygenation via a SAD

  • Second-generation SADs are recommended

  • A maximum of three attempts at SAD insertion are recommended

  • During rapid sequence induction, cricoid pressure should be removed to facilitate insertion of a SAD

  • Blind techniques for intubation through a SAD are not recommended

 
  • Failed intubation should be declared

  • The emphasis is on oxygenation via a SAD

  • Second-generation SADs are recommended

  • A maximum of three attempts at SAD insertion are recommended

  • During rapid sequence induction, cricoid pressure should be removed to facilitate insertion of a SAD

  • Blind techniques for intubation through a SAD are not recommended

 

Successful placement of a SAD creates the opportunity to stop and think about whether to wake the patient up, make a further attempt at intubation, continue anaesthesia without a tracheal tube, or rarely, to proceed directly to a tracheostomy or cricothyroidotomy.

If oxygenation through a SAD cannot be achieved after a maximum of three attempts, Plan C should be implemented.

Supraglottic airway device selection and placement

As difficulty with intubation cannot always be predicted, every anaesthetist should have a well-thought-through plan for such an eventuality. The decision about which SAD to use for rescue should have been made before induction of anaesthesia, and this choice should be determined by the clinical situation, device availability, and operator experience.

NAP4 identified the potential advantages of second-generation devices in airway rescue and recommended that all hospitals have them available for both routine use and rescue airway management.2 Competence and expertise in the insertion of any SAD requires training and practice.172–176 All anaesthetists should be trained to use and have immediate access to second-generation SADs.

Cricoid pressure and supraglottic airway device insertion

Cricoid pressure decreases hypopharyngeal space177 and impedes SAD insertion and the placement of both first- and second-generation devices.178–181 Cricoid pressure will have been removed during Plan A if laryngoscopy was difficult and (in the absence of regurgitation) should remain off during insertion of a SAD.

Second-generation supraglottic airway devices

It has been argued that second-generation SADs should be used routinely because of their efficacy and increased safety when compared with first-generation devices.182 Several second-generation SADs have been described,183–191 and it is likely that during the lifetime of these guidelines many similar devices will appear.

The ideal attributes of a SAD for airway rescue are reliable first-time placement, high seal pressure, separation of gastrointestinal and respiratory tracts, and compatibility with fibre-optically guided tracheal intubation. These attributes are variably combined in different devices.182 Of those currently available, only the i-gel™ (Intersurgical, Wokingham, UK), the Proseal™ LMA® (PLMA; Teleflex Medical Europe Ltd, Athlone, Ireland), and the LMA Supreme™ (SLMA; Teleflex Medical Ltd) have large-scale longitudinal studies,192–195 literature reviews,196 or meta-analyses in adults197–200 supporting their use. A number of studies have compared second-generation SADs,201–224 but it is important to recognize that the experience of the operator with the device also influences the chance of successful insertion.225

Limiting the number of insertion attempts

Repeated attempts at inserting a SAD increases the likelihood of airway trauma and may delay the decision to accept failure and move to an alternative technique to maintain oxygenation.

Successful placement is most likely on the first attempt. In one series, insertion success with the PLMA™ was 84.5% on the first attempt, decreasing to 36% on the fourth attempt.193 In the series of Goldmann and colleagues,194 only 4.2% of devices were placed on the third or fourth attempt. Three studies report that a third insertion attempt increased overall success rate by more than 5%; however, one was conducted with operators who had minimal experience, and the other two used the Baska® mask (Baska Versatile Laryngeal Mask, Pty Ltd, Strathfield, NSW, Australia).189,214,226 Changing to an alternative SAD has been shown to be successful.192,193,211,216,218,223,224 A maximum of three attempts at SAD insertion is recommended; two with the preferred second-generation device and another attempt with an alternative. An attempt includes changing the size of the SAD.

Even supraglottic airways can fail.227,228 If effective oxygenation has not been established after three attempts, Plan C should be implemented.

Guided supraglottic airway device placement

Bougie-aided placement of the PLMA has been described as improving first-time placement.229 In comparison studies, the bougie-guided technique was 100% effective at achieving first-time placement and more effective than digital insertion or insertion with the introducer tool.230,231 Bougie-aided placement provides better alignment of the drain port and a better fibre-optic view of the cords through the PLMA than the introducer tool method.232 Patients with a history of difficult tracheal intubation or predicted difficulty were excluded from these studies, making it unclear how effective this technique would be in this situation. The technique has been used effectively in a simulated difficult airway in patients wearing a hard collar,233 but again patients with predicted difficulty were excluded. A comparative study between the i-gel and the PLMA using a guided technique with a duodenal tube234 showed both devices to have a first-time insertion success rate of >97%. An orogastric tube has also been used effectively to facilitate PLMA placement in 3000 obstetric patients.235 Despite the apparent benefit, bougie- and gastric tube-guided placement of second-generation devices are not guaranteed to be successful.193,221 The technique requires experience, it may cause trauma,150 and it is not listed in the current PLMA instruction manual.236

Successful supraglottic airway device insertion and effective oxygenation established: ‘stop and think’

Clinical examination and capnography should be used to confirm ventilation. If effective oxygenation has been established through a SAD, it is recommended that the team stop and take the opportunity to review the most appropriate course of action.

There are four options to consider: wake the patient up; attempt intubation via the SAD using a fibre-optic scope; proceed with surgery using the supraglottic airway; or (rarely) proceed to tracheostomy or cricothyroidotomy.

Patient factors, the urgency of the surgery, and the skill set of the operator all influence the decision, but the underlying principle is to maintain oxygenation while minimizing the risk of aspiration.

Wake the patient up

If the surgery is not urgent then the safest option is to wake the patient up, and this should be considered first. This will require the full antagonism of neuromuscular block. If rocuronium or vecuronium has been used, sugammadex is an appropriate choice of antagonistic agent. If another non-depolarizing neuromuscular blocking agent has been used then anaesthesia must be maintained until paralysis can be adequately antagonized. Surgery may then be postponed or may continue after awake intubation or under regional anaesthesia.

If waking the patent up is inappropriate (for example, in the critical care unit, in the emergency department, or where life-saving surgery must proceed immediately), the remaining options should be considered.

Intubation via the supraglottic airway device

Intubation through a SAD is only appropriate if the clinical situation is stable, oxygenation is possible via the SAD, and the anaesthetist is trained in the technique. Limiting the number of airway interventions is a core principle of safe airway management; repeated attempts at intubation through a SAD are inappropriate.

Intubation through an intubating laryngeal mask airway (iLMA™; Teleflex Medical Ltd) was included in the 2004 guidelines.1 Although an overall success rate of 95.7% has been reported in a series of 1100 patients using a blind technique,237 first-attempt success rates are higher using fibre-optic guidance,238,239 and a guided technique has been shown to be of benefit in patients with difficult airways.240 The potential for serious adverse outcomes associated with blind techniques remains.241 With the need for repeated insertion attempts to achieve success238 and a low first-time success rate240,242 (even with second-generation devices243), the blind technique is redundant.

Direct fibre-optically guided intubation has been described via a number of SADs, although this may be technically challenging.244–248 Fibre-optically guided tracheal intubation through the i-gel has been reported with a high success rate.249,250 Second-generation SADs specifically designed to facilitate tracheal intubation have been described,190,251,252 but data regarding their efficacy are limited.

The use of an Aintree Intubation Catheter™ (AIC; Cook Medical, Bloomington, USA) over a fibre-optic scope allows guided intubation through a SAD where direct fibre-optically guided intubation is not possible.248,253 The technique is described on the DAS website.254 Descriptions of AIC use include a series of 128 patients with a 93% success rate through a classic Laryngeal Mask Airway.255 The patients in whom the technique was successful included 90.8% with a grade 3 or 4 Cormack and Lehane view at direct laryngoscopy and three patients in whom mask ventilation was reported to be impossible.

Aintree Intubation Catheter™-facilitated intubation has also been described with the PLMA256,257 and the i-gel.258 Aintree Intubation Catheter™-guided intubation through an LMA Supreme™ has been reported,259 but it is unreliable260 and cannot be recommended.261

Proceed with surgery using the supraglottic airway device

This should be considered as a high-risk option reserved for specific or immediately life-threatening situations and should involve input from a senior clinician. The airway may already be traumatized from several unsuccessful attempts at intubation and may deteriorate during the course of surgery because of device dislodgement, regurgitation, airway swelling, or surgical factors. Rescue options are limited given that tracheal intubation is already known to have failed.

Although waking a patient up after failed intubation is most often in their best interest, this is a difficult decision for an anaesthetist to take, especially during a crisis.241,262

Proceed to tracheostomy or cricothyroidotomy

In rare circumstances, even when it is possible to ventilate through a SAD, it may be appropriate to secure the airway with a tracheostomy or cricothyroidotomy.

Plan C. Final attempt at face-mask ventilation

If effective ventilation has not been established after three SAD insertion attempts, Plan C (Table 3) follows on directly. A number of possible scenarios are developing at this stage. During Plans A and B, it will have been determined whether face-mask ventilation was easy, difficult, or impossible, but the situation may have changed if attempts at intubation and SAD placement have traumatized the airway.

Table 3

Key features of Plan C. CICO, can't intubate can't oxygenate; SAD, supraglottic airway device

  • Failed SAD ventilation should be declared

  • Attempt to oxygenate by face mask

  • If face-mask ventilation is impossible, paralyse

  • If face-mask ventilation is possible, maintain oxygenation and wake the patient up

  • Declare CICO and start Plan D

  • Continue attempts to oxygenate by face mask, SAD, and nasal cannulae

 
  • Failed SAD ventilation should be declared

  • Attempt to oxygenate by face mask

  • If face-mask ventilation is impossible, paralyse

  • If face-mask ventilation is possible, maintain oxygenation and wake the patient up

  • Declare CICO and start Plan D

  • Continue attempts to oxygenate by face mask, SAD, and nasal cannulae

 

If face-mask ventilation results in adequate oxygenation, the patient should be woken up in all but exceptional circumstances, and this will require full antagonism of neuromuscular block.

If it is not possible to maintain oxygenation using a face mask, ensuring full paralysis before critical hypoxia develops offers a final chance of rescuing the airway without recourse to Plan D.

Sugammadex has been used to antagonize neuromuscular block during the CICO situation but does not guarantee a patent and manageable upper airway.34,263–266 Residual anaesthesia, trauma, oedema, or pre-existing upper airway pathology may all contribute to airway obstruction.33

Plan D: Emergency front-of-neck access

A CICO situation arises when attempts to manage the airway by tracheal intubation, face-mask ventilation, and SAD have failed (Table 4). Hypoxic brain damage and death will occur if the situation is not rapidly resolved.

Table 4

Key features of Plan D. CICO, can't intubate can't oxygenate

  • CICO and progression to front-of-neck access should be declared

  • A didactic scalpel technique has been selected to promote standardized training

  • Placement of a wide-bore cuffed tube through the cricothyroid membrane facilitates normal minute ventilation with a standard breathing system

  • High-pressure oxygenation through a narrow-bore cannula is associated with serious morbidity

  • All anaesthetists should be trained to perform a surgical airway

  • Training should be repeated at regular intervals to ensure skill retention

 
  • CICO and progression to front-of-neck access should be declared

  • A didactic scalpel technique has been selected to promote standardized training

  • Placement of a wide-bore cuffed tube through the cricothyroid membrane facilitates normal minute ventilation with a standard breathing system

  • High-pressure oxygenation through a narrow-bore cannula is associated with serious morbidity

  • All anaesthetists should be trained to perform a surgical airway

  • Training should be repeated at regular intervals to ensure skill retention

 

Current evidence in this area comes either from scenario-based training using manikin, cadaver, or wet lab facilities or from case series, typically in out-of-hospital or emergency department settings.267–272 None of these completely replicates the situation faced by anaesthetists delivering general anaesthesia in a hospital setting.

NAP4 provided commentary on a cohort of emergency surgical airways and cannula cricothyroidotomies performed when other methods of securing the airway during general anaesthesia had failed.2 The report highlighted a number of problems, including decision-making (delay in progression to cricothyroidotomy), knowledge gaps (not understanding how available equipment worked), system failures (specific equipment not being available), and technical failures (failure to site a cannula in the airway).

After NAP4, discussion largely focused on the choice of technique and equipment used when airway rescue failed, but the report also highlighted the importance of human factors.2,273–275

Regular training in both technical and non-technical elements is needed in order to reinforce and retain skills. Success depends on decision-making, planning, preparation, and skill acquisition, all of which can be developed and refined with repeated practice.276,277 Cognitive processing and motor skills decline under stress. A simple plan to rescue the airway using familiar equipment and rehearsed techniques is likely to increase the chance of a successful outcome. Current evidence indicates that a surgical technique best meets these criteria.2,269,273,278

A cricothyroidotomy may be performed using either a scalpel or a cannula technique. Anaesthetists must learn a scalpel technique and have regular training to avoid skill fade.279

Scalpel cricothyroidotomy

Scalpel cricothyroidotomy is the fastest and most reliable method of securing the airway in the emergency setting.269,278,280 A cuffed tube in the trachea protects the airway from aspiration, provides a secure route for exhalation, allows low-pressure ventilation using standard breathing systems, and permits end-tidal CO2 monitoring.

A number of surgical techniques have been described, but there is a lack of evidence of the superiority of one over another.268,281–283 The techniques all have steps in common: neck extension, identification of the cricothyroid membrane, incision through the skin and cricothyroid membrane, and insertion of a cuffed tracheal tube. In some descriptions, the skin and cricothyroid membrane are cut sequentially; in others, a single incision is recommended. Many include a placeholder to keep the incision open until the tube is in place. Some use specialist equipment (cricoid hook, tracheal dilators etc).

A single stab incision through the cricothyroid membrane is appealing in terms of its simplicity, but this approach may fail in the obese patient or if the anatomy is difficult, and a vertical skin incision is recommended in this situation. The approach recommended in these guidelines is a modification of previously described techniques.

Airway rescue via the front of neck should not be attempted without complete neuromuscular block. If sugammadex has been administered earlier in the strategy, a neuromuscular blocking agent other than rocuronium or vecuronium will be required.

Oxygen (100%) should be applied to the upper airway throughout, using a SAD, a tightly fitting face mask, or nasal insufflation.

The use of the ‘laryngeal handshake’ as described by Levitan281 (Fig. 3) is recommended as the first step because it promotes confidence in the recognition of the three-dimensional anatomy of the laryngeal structures; the conical cartilaginous cage consisting of the hyoid, thyroid, and cricoid. The laryngeal handshake is performed with the non-dominant hand, identifying the hyoid and thyroid laminae, stabilizing the larynx between thumb and middle finger, and moving down the neck to palpate the cricothyroid membrane with the index finger.

Fig 3

The laryngeal handshake. (a) The index finger and thumb grasp the top of the larynx (the greater cornu of the hyoid bone) and roll it from side to side. The bony and cartilaginous cage of the larynx is a cone, which connects to the trachea. (b) The fingers and thumb slide down over the thyroid laminae. (c) Middle finger and thumb rest on the cricoid cartilage, with the index finger palpating the cricothyroid membrane.

Fig 3

The laryngeal handshake. (a) The index finger and thumb grasp the top of the larynx (the greater cornu of the hyoid bone) and roll it from side to side. The bony and cartilaginous cage of the larynx is a cone, which connects to the trachea. (b) The fingers and thumb slide down over the thyroid laminae. (c) Middle finger and thumb rest on the cricoid cartilage, with the index finger palpating the cricothyroid membrane.

Standardization is useful in rarely encountered crisis situations. It is recommended that the technique described below is adopted. The technique relies on the correct equipment being immediately available. Operator position and stabilization of the hands is important.

Equipment

  1. Scalpel with number 10 blade; a broad blade (with the same width as the tracheal tube) is essential.

  2. Bougie with coude (angled) tip.

  3. Tube, cuffed, size 6.0 mm.

Patient positioning

The sniffing position used for routine airway management does not provide optimal conditions for cricothyroidotomy; in this situation, neck extension is required. In an emergency, this may be achieved by pushing a pillow under the shoulders, dropping the head of the operating table, or by pulling the patient up so that the head hangs over the top of the trolley.

Cricothyroid membrane palpable: scalpel technique (Fig. 4; ‘stab, twist, bougie, tube’)

  1. Continue attempts at rescue oxygenation via upper airway (assistant).

  2. Stand on the patient's left-hand side if you are right handed (reverse if left handed).

  3. Perform a laryngeal handshake to identify the laryngeal anatomy.

  4. Stabilize the larynx using the left hand.

  5. Use left index finger to identify the cricothyroid membrane.

  6. Hold the scalpel in your right hand, make a transverse stab incision through the skin and cricothyroid membrane with the cutting edge of the blade facing towards you.

  7. Keep the scalpel perpendicular to the skin and turn it through 90° so that the sharp edge points caudally (towards the feet).

  8. Swap hands; hold the scalpel with your left hand.

  9. Maintain gentle traction, pulling the scalpel towards you (laterally) with the left hand, keeping the scalpel handle vertical to the skin (not slanted).

  10. Pick the bougie up with your right hand.

  11. Holding the bougie parallel to the floor, at a right angle to the trachea, slide the coude tip of the bougie down the side of the scalpel blade furthest from you into the trachea.

  12. Rotate and align the bougie with the patient's trachea and advance gently up to 10–15 cm.

  13. Remove the scalpel.

  14. Stabilize trachea and tension skin with left hand.

  15. Railroad a lubricated size 6.0 mm cuffed tracheal tube over the bougie.

  16. Rotate the tube over the bougie as it is advanced. Avoid excessive advancement and endobronchial intubation.

  17. Remove the bougie.

  18. Inflate the cuff and confirm ventilation with capnography.

  19. Secure the tube.

If unsuccessful, proceed to scalpel–finger–bougie technique (below).

Fig 4

Cricothyroidotomy technique. Cricothyroid membrane palpable: scalpel technique; ‘stab, twist, bougie, tube’. (a) Identify cricothyroid membrane. (b) Make transverse stab incision through cricothyroid membrane. (c) Rotate scalpel so that sharp edge points caudally. (d) Pulling scalpel towards you to open up the incision, slide coude tip of bougie down scalpel blade into trachea. (e) Railroad tube into trachea.

Fig 4

Cricothyroidotomy technique. Cricothyroid membrane palpable: scalpel technique; ‘stab, twist, bougie, tube’. (a) Identify cricothyroid membrane. (b) Make transverse stab incision through cricothyroid membrane. (c) Rotate scalpel so that sharp edge points caudally. (d) Pulling scalpel towards you to open up the incision, slide coude tip of bougie down scalpel blade into trachea. (e) Railroad tube into trachea.

Impalpable cricothyroid membrane: scalpel–finger–bougie technique

This approach is indicated when the cricothyroid membrane is impalpable or if other techniques have failed.

Equipment, patient, and operator position are as for the scalpel technique (Fig. 5)

  1. Continue attempts at rescue oxygenation via upper airway (assistant).

  2. Attempt to identify the laryngeal anatomy using a laryngeal handshake.

  3. If an ultrasound machine is immediately available and switched on, it may help to identify the midline and major blood vessels.

  4. Tension skin using the left hand.

  5. Make an 8–10 cm midline vertical skin incision, caudad to cephalad.

  6. Use blunt dissection with fingers of both hands to separate tissues and identify and stabilize the larynx with left hand.

  7. Proceed with ‘scalpel technique’ as above.

Note that a smaller cuffed tube (including a Melker) can be used provided it fits over the bougie. The bougie should be advanced using gentle pressure; clicks may be felt as the bougie slides over the tracheal rings. ‘Hold-up’ at less than 5 cm may indicate that the bougie is pre-tracheal.

Cannula techniques

Narrow-bore (<4 mm) cannula

Cannula techniques were included in the 2004 guidelines and have been advocated for a number of reasons, including the fact that anaesthetists are much more familiar with handling cannulae than scalpels. It has been argued that reluctance to use a scalpel may delay decision-making and that choosing a cannula technique may promote earlier intervention.268

Whilst narrow-bore cannula techniques are effective in the elective setting, their limitations have been well described.2,284,285 Ventilation can be achieved only by using a high-pressure source, and this is associated with a significant risk of barotrauma.2,268,286 Failure because of kinking, malposition, or displacement of the cannula can occur even with purpose-designed cannulae, such as the Ravussin™ (VBM, Sulz, Germany).2,268 High-pressure ventilation devices may not be available in all locations, and most anaesthetists do not use them regularly. Their use in the CICO situation should be limited to experienced clinicians who use them in routine clinical practice.

Experience of training protocols carried out using high-fidelity simulation with a live animal model (wet lab) suggest that performance can be improved by following didactic teaching of rescue protocols.287 Wet lab high-fidelity simulation is unique because it provides a model that bleeds, generates real-time stress, and has absolute end-points (end-tidal CO2 or hypoxic cardiac arrest) to delineate success or failure. After observation of >10 000 clinicians performing infraglottic access on anaesthetized sheep,268,288 Heard has recommended a standard operating procedure with a 14 gauge Insyte™ (Becton, Dickinson and Company) cannula technique, with rescue oxygenation delivered via a purpose-designed Y-piece insufflator with a large-bore exhaust arm (Rapid-O2™ Meditech Systems Ltd UK). This is followed by insertion of a cuffed tracheal tube using the Melker® wire-guided kit. An algorithm, a structured teaching programme, competency-based assessment tools, and a series of videos have been developed to support this methodology and to promote standardized training.287

Further evidence of the efficacy of this technique in human practice is needed before widespread adoption can be recommended.

Wide-bore cannula over guidewire

Some wide-bore cannula kits, such as the Cook Melker® emergency cricothyrotomy set, use a wire-guided (Seldinger) technique.289 This approach is less invasive than a surgical cricothyroidotomy and avoids the need for specialist equipment for ventilation. The skills required are familiar to anaesthetists and intensivists because they are common to central line insertion and percutaneous tracheostomy; however, these techniques require fine motor control, making them less suited to stressful situations. Whilst a wire-guided technique may be a reasonable alternative for anaesthetists who are experienced with this method, the evidence suggests that a surgical cricothyroidotomy is both faster and more reliable.288

Non-Seldinger wide-bore cannula

A number of non-Seldinger wide-bore cannula-over-trochar devices are available for airway rescue. Although successful use has been reported in CICO, there have been no large studies of these devices in clinical practice.275 The diversity of commercially available devices also presents a problem because familiarity with equipment that is not universally available challenges standardization of training.

The role of ultrasound

It is good practice to attempt to identify the trachea and the cricothyroid membrane during the preoperative assessment.273 If this is not possible with inspection and palpation alone, it can often be achieved with ultrasonography.171,290 The role of ultrasound in emergency situations is limited. If immediately available and switched on it may help to identify key landmarks but should not delay airway access.171,291,292 Airway evaluation using ultrasound is a valuable skill for anaesthetists,292 and training in its use is recommended.273,293

Postoperative care and follow-up

Difficulties with airway management and the implications for postoperative care should be discussed at the end of the procedure during the sign-out section of the WHO checklist.294 In addition to a verbal handover, an airway management plan should be documented in the medical record. Many airway guidelines and airway interest groups169,295,296 (including the DAS Extubation and Obstetric Guidelines4,5) recommend that patients should be followed up by the anaesthetist in order to document and communicate difficulties with the airway. There is a close relationship between difficult intubation and airway trauma;297,298 patient follow-up allows complications to be recognized and treated. Any instrumentation of the airway can cause trauma or have adverse effects; this has been reported with videolaryngoscopes,163,166 second-generation supraglottic devices,192,193,195 and fibre-optic intubation.299 The American Society of Anesthesiologists closed claims analysis suggests that it is the pharynx and the oesophagous that are damaged most commonly during difficult intubation.298 Pharyngeal and oesophageal injury are difficult to diagnose, with pneumothorax, pneumomediastinum, or surgical emphysema present in only 50% of patients.5 Mediastinitis after airway perforation has a high mortality, and patients should be observed carefully for the triad of pain (severe sore throat, deep cervical pain, chest pain, dysphagia, painful swallowing), fever, and crepitus.297,300 They should be warned to seek medical attention should delayed symptoms of airway trauma develop.

Despite these recommendations, communication is often inadequate.301–304 The DAS Difficult Airway Alert Form is a standard template with prompts for documentation and communication.305 The desire to provide detailed clinical information must be balanced against the need for effective communication. At present, there is no UK-wide difficult airway database, although national systems such as Medic Alert have been advocated306 and can be accessed for patients with ‘Intubation Difficulties’.307

Coding is the most effective method of communicating important information to general practitioners; the code for ‘difficult tracheal intubation’ is Read Code SP2y3303,308 and should be included on discharge summaries. Read Codes in the UK will be replaced by the international SNOMED CT (Systematized Nomenclature of Medicine–Clinical Terms) by 2020.

Every failed intubation, emergency front-of-neck access, and airway-related unplanned admission should be reviewed by departmental airway leads and should be discussed at morbidity and mortality meetings.

Fig 5

Failed intubation, failed oxygenation in the paralysed, anaesthetized patient. Technique for scalpel cricothyroidotomy. Difficult Airway Society, 2015, by permission of the Difficult Airway Society. This image is not covered by the terms of the Creative Commons Licence of this publication. For permission to re-use, please contact the Difficult Airway Society.

Fig 5

Failed intubation, failed oxygenation in the paralysed, anaesthetized patient. Technique for scalpel cricothyroidotomy. Difficult Airway Society, 2015, by permission of the Difficult Airway Society. This image is not covered by the terms of the Creative Commons Licence of this publication. For permission to re-use, please contact the Difficult Airway Society.

Discussion

Complications of airway management are infrequent. The NAP4 project estimated that airway management resulted in one serious complication per 22 000 general anaesthetics, with death or brain damage complicating 1:150 000. It is not possible to study such rare events in prospective trials, so our most valuable insights come from the detailed analysis of adverse events.2,241,262

Guidelines exist to manage complex emergency problems in other areas of clinical practice, with cardiopulmonary resuscitation guidelines being an obvious example. Standardized management plans are directly transferable from one hospital to another and make it less likely that team members will encounter unfamiliar techniques and equipment during an unfolding emergency. These guidelines are directed at anaesthetists with a range of airway skills and are not specifically aimed at airway experts. Some anaesthetists may have particular areas of expertise, which can be deployed to supplement the techniques described.

The guidelines are directed at the unanticipated difficult airway, where appropriately trained surgeons may not be immediately available, so all anaesthetists must be capable of performing a cricothyroidotomy. There are some situations where these guidelines may be loosely followed in the management of patients with a known or suspected difficult airway, and in these circumstances a suitably experienced surgeon with appropriate equipment could be immediately available to perform the surgical airway on behalf of the anaesthetist.

Complications related to airway management are not limited to situations where the primary plan has been tracheal intubation; 25% of anaesthesia incidents reported to NAP4 started with the intention of managing the airway using a SAD. Whilst the key principles and techniques described in these guidelines are still appropriate in this situation, it is likely that at the point of recognizing serious difficulty the patient may not be well oxygenated or optimally positioned.

These guidelines have been created for ‘unanticipated difficulty’ with airway management, and it is important that whatever the primary plan may be, a genuine attempt has been made to identify possible difficulties with the generic Plans A, B, C, and D. Assessing mouth opening, neck mobility, and the location of the cricothyroid membrane before surgery will help to determine whether some rescue techniques are unlikely to be successful.

There are randomized controlled trials and meta-analyses supporting the use of some airway devices and techniques,197–200 but for others no high-grade evidence is available and recommendations are necessarily based on expert consensus.8 In this manuscript, individual techniques have not been listed against their levels of evidence, although other groups have taken this approach.309

Implementation of the guidelines does not obviate the need for planning at a local level. The training required to develop and maintain technical skills has been studied in relation to various aspects of airway management, including videolaryngoscopy and cricothyroidotomy.109,276,310–313 To achieve and maintain competence with devices such as videolaryngoscopes and second-generation SADs and drugs such as sugammadex, they need to be available for regular use, and local training will be necessary. New airway devices will continue to be developed and introduced into clinical practice; their place in these guidelines will need to be evaluated. Even when no single device or technique has a clear clinical benefit, limiting choice simplifies training and decision-making. In the area of airway rescue by front-of-neck access, feedback from DAS members and international experts suggested that there was a need to unify the response of anaesthetists to the ‘CICO’ emergency and to recommend a single pathway. While UK anaesthetists are required to revalidate every 5 yr and advanced airway management features in the Royal College of Anaesthetists CPD matrix314 (2A01), there is currently no specific requirement for training or retraining in cricothyroidotomy. A consistent local effort will be required to ensure that all those involved in airway management are trained and familiar with the technique. These guidelines recommend the adoption of scalpel cricothyroidotomy as a technique that should be learned by all anaesthetists. This method was selected because it can be performed using equipment available at almost every location where an anaesthetic is performed and because insertion of a large-bore cuffed tube provides protection against aspiration, an unobstructed route for exhalation and the ability to monitor end-tidal CO2. There are, however, other valid techniques for front-of-neck access, which may continue to be provided in some hospitals where additional equipment and comprehensive training programmes are available. It is incumbent on the anaesthetic community to ensure that data from all front-of-neck access techniques are gathered and are used to inform change when these guidelines are next updated.

Declaration of interest

C.F. has received funding for travel expenses from Intavent to give lectures at a conference and from Teleflex to attend an advisory board meeting regarding product development (no fees or honoraria paid). V.S.M. has received equipment and logistical support to conduct airway workshops from Accutronic, Airtraq, AMBU, Cook, Fisher & Paykel, Intersurgical, Karl Storz, Laerdal, McGrath videoaryngoscopes, Olympus, Pentax, Smiths Medical, Teleflex, and VBM. A.F.M. received a one-off unrestricted lecture fee from AMBU to discuss fibre-optic intubation in September 2011. A.F.M. has been given trial products by AMBU for clinical use and evaluation (AMBU Auragain February/March 2014). A.F.M. was loaned three McGrath MAC videolaryngoscopes for departmental use by Aircraft Medical. A.F.M. has been loaned eight optiflow humidifer units for use across all acute hospitals in NHS Lothian and has been funded for attendance at a THRIVE study and development day (hotel accommodation for two nights) by Fisher & Paykel. A.F.M. has been loaned equipment for workshops by Accutronic, Aircraft Medical, AMBU, Cook, Fannin, Freelance, Storz, and Teleflex Medical. A.F.M. acted as an advisor to NICE Medical Technology Evaluation Programme (unpaid) for the AMBU A2scope. C.M. has received equipment to conduct airway workshops from Karl-Storz, AMBU, Fannin UK, Freelance Surgical and Verathon. R.B. has been loaned products for departmental and workshop use by AMBU, Cook, Fisher & Paykel, Karl Storz and Teleflex. A.P. has received funding for travel and accommodation to give lectures from Laryngeal Mask Company, Venner Medical, and Fisher & Paykel and has worked with these companies, acting as a consultant for product development with research funding support. E.P.O.' is a member of the Editorial Board of the British Journal of Anaesthesia. She has also acted as a consultant to AMBU (unpaid). N.M.W.'s department has received equipment from Olympus/Keymed for teaching purposes. I.A. has received travel funding for national and international lectures by Fisher & Paykel.

Funding

The Difficult Airway Society; The Royal College of Anaesthetists.

Acknowledgements

We thank Christopher Acott (Australia), Takashi Asai (Japan), Paul Baker (New Zealand), David Ball (UK), Elizabeth Behringer (USA), Timothy Cook (UK), Richard Cooper (Canada), Valerie Cunningham (UK), James Dinsmore (UK), Robert Greif (Switzerland), Peter Groom (UK), Ankie Hamaekers (The Netherlands), Andrew Heard (Australia), Thomas Heidegger (Switzerland), Andrew Higgs (UK), Eric Hodgson (South Africa), Fiona Kelly (UK), Michael Seltz Kristensen (Denmark), David Lacquiere (UK), Richard Levitan (USA), Eamon McCoy (UK), Barry McGuire (UK), Sudheer Medakkar (UK), Mary Mushambi (UK), Jaideep Pandit (UK), Bhavesh Patel (UK), Adrian Pearce (UK), Jairaj Rangasami (UK), Jim Roberts (UK), Massimiliano Sorbello (Italy), Mark Stacey (UK), Anthony Turley (UK), Matthew Turner (UK), and Nicholas Wharton (UK) for reviewing and commenting on early drafts of the paper. We thank Mansukh Popat for assisting the group when it was formed, for reviewing abstracts, and for contributing to the initial draft of Plan A. We thank Christopher Thompson for reviewing early drafts of the paper and for producing drawings illustrating Plan D. We thank Anna Brown, Mark Bennett, Sue Booth, Andy Doyle, Rebecca Gowee, Julie Kenny, and Maria Niven, librarians at University Hospital Coventry & Warwickshire NHS Trust, for help with the literature search and retrieval of selected full-text articles.

References

1
Henderson
JJ
Popat
MT
Latto
IP
Pearce
AC
.
Difficult Airway Society guidelines for management of the unanticipated difficult intubation
.
Anaesthesia
 
2004
;
59
:
675
94
2
4th National Audit Project of The Royal College of Anaesthetists and The Difficult Airway Society
.
Major complications of airway management in the United Kingdom, Report and Findings
 .
Royal College of Anaesthetists, London
,
2011
3
Black
AE
Flynn
PER
Smith
HL
Thomas
ML
Wilkinson
KA
.
Development of a guideline for the management of the unanticipated difficult airway in pediatric practice
.
Paediatr Anaesth
 
2015
;
25
:
346
62
4
Mushambi
MC
Kinsella
SM
Popat
M
et al
Obstetric Anaesthetists’ Association and Difficult Airway Society guidelines for the management of difficult and failed tracheal intubation in obstetrics
.
Anaesthesia
 
2015
;
70
:
1286
1306
5
Popat
M
Mitchell
V
Dravid
R
Patel
A
Swampillai
C
Higgs
A
.
Difficult Airway Society Guidelines for the management of tracheal extubation
.
Anaesthesia
 
2012
;
67
:
318
40
6
Hung
O
Murphy
M
.
Context-sensitive airway management
.
Anesth Analg
 
2010
;
110
:
982
3
7
Weller
JM
Merry
AF
Robinson
BJ
Warman
GR
Janssen
A
.
The impact of trained assistance on error rates in anaesthesia: a simulation-based randomised controlled trial
.
Anaesthesia
 
2009
;
64
:
126
30
8
Smith
AF
.
Creating guidelines and treating patients when there are no trials or systematic reviews
.
Eur J Anaesthesiol
 
2013
;
30
:
383
5
9
Flin
R
Fioratou
E
Frerk
C
Trotter
C
Cook
TM
.
Human factors in the development of complications of airway management: preliminary evaluation of an interview tool
.
Anaesthesia
 
2013
;
68
:
817
25
10
Reason
J
.
Human error: models and management
.
Br Med J
 
2000
;
320
:
768
70
11
Stiegler
MP
Neelankavil
JP
Canales
C
Dhillon
A
.
Cognitive errors detected in anaesthesiology: a literature review and pilot study
.
Br J Anaesth
 
2012
;
108
:
229
35
12
Greenland
KB
Acott
C
Segal
R
Goulding
G
Riley
RH
Merry
AF
.
Emergency surgical airway in life-threatening acute airway emergencies—why are we so reluctant to do it?
Anaesth Intensive Care
 
2011
;
39
:
578
84
13
Marshall
S
.
The use of cognitive aids during emergencies in anesthesia: a review of the literature
.
Anesth Analg
 
2013
;
117
:
1162
71
14
Chrimes
N
Fritz
P
.
The Vortex Approach 2013
.
Available from http://vortexapproach.com/Vortex_Approach/Vortex.html (accessed 18 May 2015)
15
ANZCA CPD Standards for Can't Intubate Can't Oxygenate (CICO) education session
.
16
ANZCA Learning Objectives for CICO Course
.
17
Frengley
RW
Weller
JM
Torrie
J
et al
The effect of a simulation-based training intervention on the performance of established critical care unit teams
.
Crit Care Med
 
2011
;
39
:
2605
11
18
Capella
J
Smith
S
Philp
A
et al
Teamwork training improves the clinical care of trauma patients
.
J Surg Educ
 
2010
;
67
:
439
43
19
CaPS Clinical Governance Unit
.
Communication and Patient Safety Course notes
.
20
Kheterpal
S
Healy
D
Aziz
MF
et al
Incidence, predictors, and outcome of difficult mask ventilation combined with difficult laryngoscopy: a report from the multicenter perioperative outcomes group
.
Anesthesiology
 
2013
;
119
:
1360
9
21
Nørskov
AK
Rosenstock
CV
Wetterslev
J
Astrup
G
Afshari
A
Lundstrøm
LH
.
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
.
Anaesthesia
 
2015
;
70
:
272
81
22
Shiga
T
Wajima
Z
Inoue
T
Sakamoto
A
.
Predicting difficult intubation in apparently normal patients: a meta-analysis of bedside screening test performance
.
Anesthesiology
 
2005
;
103
:
429
37
23
Haynes
AB
Weiser
TG
Berry
WR
et al
A surgical safety checklist to reduce morbidity and mortality in a global population
.
N Engl J Med
 
2009
;
360
:
491
9
24
Modified version of the WHO Checklist for UK 2009
.
Available from http://www.nrls.npsa.nhs.uk/resources/?entryid45=59860 (accessed 30 May 2015)
25
Perry
JJ
Lee
JS
Sillberg
VAH
Wells
GA
.
Rocuronium versus succinylcholine for rapid sequence induction intubation
.
Cochrane Database Syst Rev
 
2008
;
16
:
CD002788
26
Sluga
M
Ummenhofer
W
Studer
W
Siegemund
M
Marsch
SC
.
Rocuronium versus succinylcholine for rapid sequence induction of anesthesia and endotracheal intubation: a prospective, randomized trial in emergent cases
.
Anesth Analg
 
2005
;
101
:
1356
61
27
Karcioglu
O
Arnold
J
Topacoglu
H
Ozucelik
DN
Kiran
S
Sonmez
N
.
Succinylcholine or rocuronium? A meta-analysis of the effects on intubation conditions
.
Int J Clin Pract
 
2006
;
60
:
1638
46
28
Mallon
WK
Keim
SM
Shoenberger
JM
Walls
RM
.
Rocuronium vs. succinylcholine in the emergency department: a critical appraisal
.
J Emerg Med
 
2009
;
37
:
183
8
29
Marsch
SC
Steiner
L
Bucher
E
et al
Succinylcholine versus rocuronium for rapid sequence intubation in intensive care: a prospective, randomized controlled trial
.
Crit Care
 
2011
;
15
:
R199
30
Sørensen
MK
Bretlau
C
Gätke
MR
Sørensen
AM
Rasmussen
LS
.
Rapid sequence induction and intubation with rocuronium–sugammadex compared with succinylcholine: a randomized trial
.
Br J Anaesth
 
2012
;
108
:
682
9
31
Tang
L
Li
S
Huang
S
Ma
H
Wang
Z
.
Desaturation following rapid sequence induction using succinylcholine vs. rocuronium in overweight patients
.
Acta Anaesthesiol Scand
 
2011
;
55
:
203
8
32
Taha
SK
El-Khatib
MF
Baraka
AS
et al
Effect of suxamethonium vs rocuronium on onset of oxygen desaturation during apnoea following rapid sequence induction
.
Anaesthesia
 
2010
;
65
:
358
61
33
Curtis
R
Lomax
S
Patel
B
.
Use of sugammadex in a ‘can't intubate, can't ventilate’ situation
.
Br J Anaesth
 
2012
;
108
:
612
4
34
Kyle
BC
Gaylard
D
Riley
RH
.
A persistent ‘can't intubate, can't oxygenate’ crisis despite rocuronium reversal with sugammadex
.
Anaesth Intensive Care
 
2012
;
40
:
344
6
35
Bisschops
MMA
Holleman
C
Huitink
JM
.
Can sugammadex save a patient in a simulated ‘cannot intubate, cannot ventilate’ situation?
Anaesthesia
 
2010
;
65
:
936
41
36
Lee
C
Jahr
JS
Candiotti
KA
Warriner
B
Zornow
MH
Naguib
M
.
Reversal of profound neuromuscular block by sugammadex administered three minutes after rocuronium: a comparison with spontaneous recovery from succinylcholine
.
Anesthesiology
 
2009
;
110
:
1020
5
37
Koerber
JP
Roberts
GEW
Whitaker
R
Thorpe
CM
.
Variation in rapid sequence induction techniques: current practice in Wales
.
Anaesthesia
 
2009
;
64
:
54
9
38
Salem
MR
Sellick
BA
Elam
JO
.
The historical background of cricoid pressure in anesthesia and resuscitation
.
Anesth Analg
 
1974
;
53
:
230
2
39
Sellick
BA
.
Cricoid pressure to control regurgitation of stomach contents during induction of anaesthesia
.
Lancet
 
1961
;
2
:
404
6
40
Hartsilver
EL
Vanner
RG
.
Airway obstruction with cricoid pressure
.
Anaesthesia
 
2000
;
55
:
208
11
41
Vanner
RG
Asai
T
.
Safe use of cricoid pressure
.
Anaesthesia
 
1999
;
54
:
1
3
42
Vanner
R
.
Techniques of cricoid pressure
.
Anaesth Intensive Care Med
 
2001
;
2
:
362
3
43
Tournadre
JP
Chassard
D
Berrada
KR
Boulétreau
P
.
Cricoid cartilage pressure decreases lower esophageal sphincter tone
.
Anesthesiology
 
1997
;
86
:
7
9
44
Salem
MR
Bruninga
KW
Dodlapatii
J
Joseph
NJ
.
Metoclopramide does not attenuate cricoid pressure-induced relaxation of the lower esophageal sphincter in awake volunteers
.
Anesthesiology
 
2008
;
109
:
806
10
45
Vanner
RG
Clarke
P
Moore
WJ
Raftery
S
.
The effect of cricoid pressure and neck support on the view at laryngoscopy
.
Anaesthesia
 
1997
;
52
:
896
900
46
Meek
T
Gittins
N
Duggan
JE
.
Cricoid pressure: knowledge and performance amongst anaesthetic assistants
.
Anaesthesia
 
1999
;
54
:
59
62
47
Palmer
JHM
Ball
DR
.
The effect of cricoid pressure on the cricoid cartilage and vocal cords: an endoscopic study in anaesthetised patients
.
Anaesthesia
 
2000
;
55
:
263
8
48
Shorten
GD
Alfille
PH
Gliklich
RE
.
Airway obstruction following application of cricoid pressure
.
J Clin Anesth
 
1991
;
3
:
403
5
49
Ansermino
JM
Blogg
CE
.
Cricoid pressure may prevent insertion of the laryngeal mask airway
.
Br J Anaesth
 
1992
;
69
:
465
7
50
Aoyama
K
Takenaka
I
Sata
T
Shigematsu
A
.
Cricoid pressure impedes positioning and ventilation through the laryngeal mask airway
.
Can J Anaesth
 
1996
;
43
:
1035
40
51
Hocking
G
Roberts
FL
Thew
ME
.
Airway obstruction with cricoid pressure and lateral tilt
.
Anaesthesia
 
2001
;
56
:
825
8
52
Allman
KG
.
The effect of cricoid pressure application on airway patency
.
J Clin Anesth
 
1995
;
7
:
197
9
53
Warters
RD
Szabo
T
Spinale
FG
Desantis
SM
Reves
JG
.
The effect of neuromuscular blockade on mask ventilation
.
Anaesthesia
 
2011
;
66
:
163
7
54
Sachdeva
R
Kannan
TR
Mendonca
C
Patteril
M
.
Evaluation of changes in tidal volume during mask ventilation following administration of neuromuscular blocking drugs
.
Anaesthesia
 
2014
;
69
:
826
31
55
Connelly
NR
Ghandour
K
Robbins
L
Dunn
S
Gibson
C
.
Management of unexpected difficult airway at a teaching institution over a 7-year period
.
J Clin Anesth
 
2006
;
18
:
198
204
56
Sakles
JC
Chiu
S
Mosier
J
Walker
C
Stolz
U
.
The importance of first pass success when performing orotracheal intubation in the emergency department
.
Acad Emerg Med
 
2013
;
20
:
71
8
57
Peterson
GN
Domino
KB
Caplan
RA
Posner
KL
Lee
LA
Cheney
FW
.
Management of the difficult airway: a closed claims analysis
.
Anesthesiology
 
2005
;
103
:
33
9
58
El-Orbany
M
Woehlck
H
Salem
MR
.
Head and neck position for direct laryngoscopy
.
Anesth Analg
 
2011
;
113
:
103
9
59
Adnet
F
Baillard
C
Borron
SW
et al
Randomized study comparing the ‘sniffing position’ with simple head extension for laryngoscopic view in elective surgery patients
.
Anesthesiology
 
2001
;
95
:
836
41
60
Magill
IW
.
Technique in endotracheal anaesthesia
.
Br Med J
 
1930
;
2
:
817
9
61
Collins
JS
Lemmens
HJM
Brodsky
JB
Brock-Utne
JG
Levitan
RM
.
Laryngoscopy and morbid obesity: a comparison of the ‘sniff’ and ‘ramped’ positions
.
Obes Surg
 
2004
;
14
:
1171
5
62
Murphy
C
Wong
DT
.
Airway management and oxygenation in obese patients
.
Can J Anaesth
 
2013
;
60
:
929
45
63
Ranieri
D
Filho
SM
Batista
S
Do Nascimento
P
.
Comparison of Macintosh and AirtraqTM laryngoscopes in obese patients placed in the ramped position
.
Anaesthesia
 
2012
;
67
:
980
5
64
Rao
SL
Kunselman
AR
Schuler
HG
Desharnais
S
.
Laryngoscopy and tracheal intubation in the head-elevated position in obese patients: a randomized, controlled, equivalence trial
.
Anesth Analg
 
2008
;
107
:
1912
8
65
Weingart
SD
Levitan
RM
.
Preoxygenation and prevention of desaturation during emergency airway management
.
Ann Emerg Med.
 
2012
;
59
:
165
75
66
Cattano
D
Melnikov
V
Khalil
Y
Sridhar
S
Hagberg
CA
.
An evaluation of the rapid airway management positioner in obese patients undergoing gastric bypass or laparoscopic gastric banding surgery
.
Obes Surg
 
2010
;
20
:
1436
41
67
Bell
MDD
.
Routine pre-oxygenation – a new ‘minimum standard’ of care?
Anaesthesia
 
2004
;
59
:
943
5
68
McGowan
P
Skinner
A
.
Preoxygenation—the importance of a good face mask seal
.
Br J Anaesth
 
1995
;
75
:
777
8
69
Tanoubi
I
Drolet
P
Donati
F
.
Optimizing preoxygenation in adults
.
Can J Anaesth
 
2009
;
56
:
449
66
70
Nimmagadda
U
Chiravuri
SD
Salem
MR
et al
Preoxygenation with tidal volume and deep breathing techniques: the impact of duration of breathing and fresh gas flow
.
Anesth Analg
 
2001
;
92
:
1337
41
71
Pandey
M
Ursekar
R
Aphale
S
.
Three minute tidal breathing – a gold standard techniques for pre-oxygenation for elective surgeries
.
Innov J Med Health Sci
 
2014
;
4
:
194
7
72
Pandit
JJ
Duncan
T
Robbins
PA
.
Total oxygen uptake with two maximal breathing techniques and the tidal volume breathing technique: a physiologic study of preoxygenation
.
Anesthesiology
 
2003
;
99
:
841
6
73
Russell
EC
Wrench
I
Feast
M
Mohammed
F
.
Pre-oxygenation in pregnancy: the effect of fresh gas flow rates within a circle breathing system
.
Anaesthesia
 
2008
;
63
:
833
6
74
Taha
SK
El-Khatib
MF
Siddik-Sayyid
SM
et al
Preoxygenation by 8 deep breaths in 60 seconds using the Mapleson A (Magill), the circle system, or the Mapleson D system
.
J Clin Anesth
 
2009
;
21
:
574
8
75
Baraka
AS
Taha
SK
Aouad
MT
El-Khatib
MF
Kawkabani
NI
.
Preoxygenation: comparison of maximal breathing and tidal volume breathing techniques
.
Anesthesiology
 
1999
;
91
:
612
6
76
Drummond
GB
Park
GR
.
Arterial oxygen saturation before intubation of the trachea. An assessment of oxygenation techniques
.
Br J Anaesth
 
1984
;
56
:
987
93
77
Hirsch
J
Führer
I
Kuhly
P
Schaffartzik
W
.
Preoxygenation: a comparison of three different breathing systems
.
Br J Anaesth
 
2001
;
87
:
928
31
78
Nimmagadda
U
Salem
MR
Joseph
NJ
Miko
I
.
Efficacy of preoxygenation using tidal volume and deep breathing techniques with and without prior maximal exhalation
.
Can J Anaesth
 
2007
;
54
:
448
52
79
Gagnon
C
Fortier
L-P
Donati
F
.
When a leak is unavoidable, preoxygenation is equally ineffective with vital capacity or tidal volume breathing
.
Can J Anaesth
 
2006
;
53
:
86
91
80
Dixon
BJ
Dixon
JB
Carden
JR
et al
Preoxygenation is more effective in the 25 degrees head-up position than in the supine position in severely obese patients: a randomized controlled study
.
Anesthesiology
 
2005
;
102
:
1110
5
81
Lane
S
Saunders
D
Schofield
A
Padmanabhan
R
Hildreth
A
Laws
D
.
A prospective, randomised controlled trial comparing the efficacy of pre-oxygenation in the 20 degrees head-up vs supine position
.
Anaesthesia
 
2005
;
60
:
1064
7
82
Cressey
DM
Berthoud
MC
Reilly
CS
.
Effectiveness of continuous positive airway pressure to enhance pre-oxygenation in morbidly obese women
.
Anaesthesia
 
2001
;
56
:
680
4
83
Gander
S
Frascarolo
P
Suter
M
Spahn
DR
Magnusson
L
.
Positive end-expiratory pressure during induction of general anesthesia increases duration of nonhypoxic apnea in morbidly obese patients
.
Anesth Analg
 
2005
;
100
:
580
4
84
Herriger
A
Frascarolo
P
Spahn
DR
Magnusson
L
.
The effect of positive airway pressure during pre-oxygenation and induction of anaesthesia upon duration of non-hypoxic apnoea
.
Anaesthesia
 
2004
;
59
:
243
7
85
Taha
SK
Siddik-Sayyid
SM
El-Khatib
MF
Dagher
CM
Hakki
MA
Baraka
AS
.
Nasopharyngeal oxygen insufflation following pre-oxygenation using the four deep breath technique
.
Anaesthesia
 
2006
;
61
:
427
30
86
Ramachandran
SK
Cosnowski
A
Shanks
A
Turner
CR
.
Apneic oxygenation during prolonged laryngoscopy in obese patients: a randomized, controlled trial of nasal oxygen administration
.
J Clin Anesth
 
2010
;
22
:
164
8
87
Levitan
RM
.
NO DESAT! Nasal Oxygen During Efforts Securing A Tube 2010
.
88
Patel
A
Nouraei
SA
.
Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE): a physiological method of increasing apnoea time in patients with difficult airways
.
Anaesthesia
 
2015
;
70
:
323
9
89
Miguel-Montanes
R
Hajage
D
Messika
J
et al
Use of high-flow nasal cannula oxygen therapy to prevent desaturation during tracheal intubation of intensive care patients with mild-to-moderate hypoxemia
.
Crit Care Med
 
2015
;
43
:
574
83
90
Vourc'h
M
Asfar
P
Volteau
C
et al
High-flow nasal cannula oxygen during endotracheal intubation in hypoxemic patients: a randomized controlled clinical trial
.
Intensive Care Med
 
2015
;
41
:
1538
48
91
Brown
GW
Ellis
FR
.
Comparison of propofol and increased doses of thiopentone for laryngeal mask insertion
.
Acta Anaesthesiol Scand
 
1995
;
39
:
1103
4
92
Ti
LK
Chow
MY
Lee
TL
.
Comparison of sevoflurane with propofol for laryngeal mask airway insertion in adults
.
Anesth Analg
 
1999
;
88
:
908
12
93
Sury
MRJ
Palmer
JHMG
Cook
TM
Pandit
JJ
.
The State of UK anaesthesia: a survey of National Health Service activity in 2013
.
Br J Anaesth
 
2014
;
113
:
575
84
94
MacG Palmer
J
Pandit
JJ
.
AAGA during induction of anaesthesia and transfer into theatre
. In:
Pandit
JJ
Cook
TM
, eds.
5th National Audit Project of the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland
 .
London
:
Accidental Awareness during General Anaesthesia in the United Kingdom and Ireland
,
2014
;
63
76
95
Broomhead
RH
Marks
RJ
Ayton
P
.
Confirmation of the ability to ventilate by facemask before administration of neuromuscular blocker: a non-instrumental piece of information?
Br J Anaesth
 
2010
;
104
:
313
7
96
Calder
I
Yentis
SM
.
Could ‘safe practice’ be compromising safe practice? Should anaesthetists have to demonstrate that face mask ventilation is possible before giving a neuromuscular blocker?
Anaesthesia
 
2008
;
63
:
113
5
97
Chambers
D
Paulden
M
Paton
F
et al
Sugammadex for reversal of neuromuscular block after rapid sequence intubation: a systematic review and economic assessment
.
Br J Anaesth
 
2010
;
105
:
568
75
98
Reddy
JI
Cooke
PJ
van Schalkwyk
JM
Hannam
JA
Fitzharris
P
Mitchell
SJ
.
Anaphylaxis is more common with rocuronium and succinylcholine than with atracurium
.
Anesthesiology
 
2015
;
122
:
39
45
99
Sadleir
PHM
Clarke
RC
Bunning
DL
Platt
PR
.
Anaphylaxis to neuromuscular blocking drugs: incidence and cross-reactivity in Western Australia from 2002 to 2011
.
Br J Anaesth
 
2013
;
110
:
981
7
100
Von Goedecke
A
Voelckel
WG
Wenzel
V
et al
Mechanical versus manual ventilation via a face mask during the induction of anesthesia: a prospective, randomized, crossover study
.
Anesth Analg
 
2004
;
98
:
260
3
101
Isono
S
Tanaka
A
Ishikawa
T
Tagaito
Y
Nishino
T
.
Sniffing position improves pharyngeal airway patency in anesthetized patients with obstructive sleep apnea
.
Anesthesiology
 
2005
;
103
:
489
94
102
El-Orbany
M
Woehlck
HJ
.
Difficult mask ventilation
.
Anesth Analg
 
2009
;
109
:
1870
80
103
Ramachandran
SK
Kheterpal
S
.
Difficult mask ventilation: does it matter?
Anaesthesia
 
2011
;
66
:
40
4
104
Niforopoulou
P
Pantazopoulos
I
Demestiha
T
Koudouna
E
Xanthos
T
.
Video-laryngoscopes in the adult airway management: a topical review of the literature
.
Acta Anaesthesiol Scand
 
2010
;
54
:
1050
61
105
Griesdale
DEG
Liu
D
McKinney
J
Choi
PT
.
Glidescope® video-laryngoscopy versus direct laryngoscopy for endotracheal intubation: a systematic review and meta-analysis
.
Can J Anaesth
 
2012
;
59
:
41
52
106
Andersen
LH
Rovsing
L
Olsen
KS
.
GlideScope videolaryngoscope vs. Macintosh direct laryngoscope for intubation of morbidly obese patients: a randomized trial
.
Acta Anaesthesiol Scand
 
2011
;
55
:
1090
7
107
Cooper
RM
Pacey
JA
Bishop
MJ
Cooper
RM
.
Cardiothoracic anesthesia, respiration and airway; early clinical experience with a new videolaryngoscope (GlideScope®) in 728 patients
.
Can J Anaesth
 
2005
;
52
:
191
8
108
Thong
SY
Lim
Y
.
Video and optic laryngoscopy assisted tracheal intubation—the new era
.
Anaesth Intensive Care
 
2009
;
37
:
219
33
109
Aziz
MF
Dillman
D
Fu
R
Brambrink
AM
.
Comparative effectiveness of the C-MAC video laryngoscope versus direct laryngoscopy in the setting of the predicted difficult airway
.
Anesthesiology
 
2012
;
116
:
629
36
110
Mosier
JM
Whitmore
SP
Bloom
JW
et al
Video laryngoscopy improves intubation success and reduces esophageal intubations compared to direct laryngoscopy in the medical intensive care unit
.
Crit Care
 
2013
;
17
:
R237
111
Asai
T
Liu
EH
Matsumoto
S
et al
Use of the Pentax-AWS in 293 patients with difficult airways
.
Anesthesiology
 
2009
;
110
:
898
904
112
Cavus
E
Neumann
T
Doerges
V
et al
First clinical evaluation of the C-MAC D-blade videolaryngoscope during routine and difficult intubation
.
Anesth Analg
 
2011
;
112
:
382
5
113
Jungbauer
A
Schumann
M
Brunkhorst
V
Börgers
A
Groeben
H
.
Expected difficult tracheal intubation: a prospective comparison of direct laryngoscopy and video laryngoscopy in 200 patients
.
Br J Anaesth
 
2009
;
102
:
546
50
114
Ericsson
KA
.
Deliberate practice and the acquisition and maintenance of expert performance in medicine and related domains
.
Acad Med
 
2004
;
79
:
S70
81
115
Zaouter
C
Calderon
J
Hemmerling
TM
.
Videolaryngoscopy as a new standard of care
.
Br J Anaesth
 
2015
;
114
:
181
3
116
Kok
T
George
RB
McKeen
D
Vakharia
N
Pink
A
.
Effectiveness and safety of the Levitan FPS ScopeTM for tracheal intubation under general anesthesia with a simulated difficult airway
.
Can J Anaesth
 
2012
;
59
:
743
50
117
Aziz
M
Metz
S
.
Clinical evaluation of the Levitan Optical Stylet
.
Anaesthesia
 
2011
;
66
:
579
81
118
Bein
B
Yan
M
Tonner
PH
Scholz
J
Steinfath
M
Dörges
V
.
Tracheal intubation using the Bonfils intubation fibrescope after failed direct laryngoscopy
.
Anaesthesia
 
2004
;
59
:
1207
9
119
Byhahn
C
Nemetz
S
Breitkreutz
R
Zwissler
B
Kaufmann
M
Meininger
D
.
Brief report: tracheal intubation using the Bonfils intubation fibrescope or direct laryngoscopy for patients with a simulated difficult airway
.
Can J Anaesth
 
2008
;
55
:
232
7
120
Thong
SY
Wong
TG
.
Clinical uses of the Bonfils Retromolar Intubation Fiberscope: a review
.
Anesth Analg
 
2012
;
115
:
855
66
121
Webb
A
Kolawole
H
Leong
S
Loughnan
TE
Crofts
T
Bowden
C
.
Comparison of the Bonfils and Levitan optical stylets for tracheal intubation: a clinical study
.
Anaesth Intensive Care
 
2011
;
39
:
1093
7
122
Phua
DS
Mah
CL
Wang
CF
.
The Shikani optical stylet as an alternative to the GlideScope® videolaryngoscope in simulated difficult intubations—a randomised controlled trial
.
Anaesthesia
 
2012
;
67
:
402
6
123
Koh
KF
Hare
JD
Calder
I
.
Small tubes revisited
.
Anaesthesia
 
1998
;
53
:
46
50
124
Marfin
AG
Iqbal
R
Mihm
F
Popat
MT
Scott
SH
Pandit
JJ
.
Determination of the site of tracheal tube impingement during nasotracheal fibreoptic intubation
.
Anaesthesia
 
2006
;
61
:
646
50
125
Jackson
AH
Orr
B
Yeo
C
Parker
C
Craven
R
Greenberg
SL
.
Multiple sites of impingement of a tracheal tube as it is advanced over a fibreoptic bronchoscope or tracheal tube introducer in anaesthetized, paralysed patients
.
Anaesth Intensive Care
 
2006
;
34
:
444
9
126
Jafari
A
Gharaei
B
Kamranmanesh
MR
et al
Wire reinforced endotracheal tube compared with Parker Flex-Tip tube for oral fiberoptic intubation: a randomized clinical trial
.
Minerva Anestesiol
 
2014
;
80
:
324
9
127
Heidegger
T
.
Videos in clinical medicine. Fiberoptic intubation
.
N Engl J Med
 
2011
;
364
:
e42
128
Barker
KF
Bolton
P
Cole
S
Coe
PA
.
Ease of laryngeal passage during fibreoptic intubation: a comparison of three endotracheal tubes
.
Acta Anaesthesiol Scand
 
2001
;
45
:
624
6
129
Dogra
S
Falconer
R
Latto
IP
.
Successful difficult intubation. Tracheal tube placement over a gum-elastic bougie
.
Anaesthesia
 
1990
;
45
:
774
6
130
Brull
SJ
Wiklund
R
Ferris
C
Connelly
NR
Ehrenwerth
J
Silverman
DG
.
Facilitation of fiberoptic orotracheal intubation with a flexible tracheal tube
.
Anesth Analg
 
1994
;
78
:
746
8
131
Kristensen
MS
.
The Parker Flex-Tip tube versus a standard tube for fiberoptic orotracheal intubation: a randomized double-blind study
.
Anesthesiology
 
2003
;
98
:
354
8
132
Suzuki
A
Tampo
A
Abe
N
et al
The Parker Flex-Tip tracheal tube makes endotracheal intubation with the Bullard laryngoscope easier and faster
.
Eur J Anaesthesiol
 
2008
;
25
:
43
7
133
Mort
TC
.
Emergency tracheal intubation: complications associated with repeated laryngoscopic attempts
.
Anesth Analg
 
2004
;
99
:
607
13
134
Hasegawa
K
Shigemitsu
K
Hagiwara
Y
et al
Association between repeated intubation attempts and adverse events in emergency departments: an analysis of a multicenter prospective observational study
.
Ann Emerg Med
 
2012
;
60
:
749
54
135
Martin
LD
Mhyre
JM
Shanks
AM
Tremper
KK
Kheterpal
S
.
3,423 emergency tracheal intubations at a university hospital: airway outcomes and complications
.
Anesthesiology
 
2011
;
114
:
42
8
136
Griesdale
DEG
Bosma
TL
Kurth
T
Isac
G
Chittock
DR
.
Complications of endotracheal intubation in the critically ill
.
Intensive Care Med
 
2008
;
34
:
1835
42
137
Schmitt
HJ
Mang
H
.
Head and neck elevation beyond the sniffing position improves laryngeal view in cases of difficult direct laryngoscopy
.
J Clin Anesth
 
2002
;
14
:
335
8
138
Knill
RL
.
Difficult laryngoscopy made easy with a ‘BURP
’.
Can J Anaesth
 
1993
;
40
:
279
82
139
Relle
A
.
Difficult laryngoscopy — “BURP”
.
Can J Anaesth
 
1993
;
40
:
798
9
140
Lam
AM
.
The difficult airway and BURP — a truly Canadian perspective
.
Can J Anaesth
 
1999
;
46
:
298
9
141
Benumof
JL
.
Difficult laryngoscopy: obtaining the best view
.
Can J Anaesth
 
1994
;
41
:
361
5
142
Levitan
RM
Mickler
T
Hollander
JE
.
Bimanual laryngoscopy: a videographic study of external laryngeal manipulation by novice intubators
.
Ann Emerg Med
 
2002
;
40
:
30
7
143
Kaplan
MB
Ward
DS
Berci
G
.
A new video laryngoscope—an aid to intubation and teaching
.
J Clin Anesth
 
2002
;
14
:
620
6
144
Murphy
MF
Hung
OR
Law
JA
.
Tracheal intubation: tricks of the trade
.
Emerg Med Clin North Am
 
2008
;
26
:
1001
14
145
Latto
IP
Stacey
M
Mecklenburgh
J
Vaughan
RS
.
Survey of the use of the gum elastic bougie in clinical practice
.
Anaesthesia
 
2002
;
57
:
379
84
146
Jabre
P
Combes
X
Leroux
B
et al
Use of gum elastic bougie for prehospital difficult intubation
.
Am J Emerg Med
 
2005
;
23
:
552
5
147
Hodzovic
I
Wilkes
AR
Latto
IP
.
To shape or not to shape … simulated bougie-assisted difficult intubation in a manikin
.
Anaesthesia
 
2003
;
58
:
792
7
148
Kelly
FE
Seller
C
.
Snail trail
.
Anaesthesia
 
2015
;
70
:
501
149
Takenaka
I
Aoyama
K
Iwagaki
T
Ishimura
H
Takenaka
Y
Kadoya
T
.
Approach combining the Airway Scope and the bougie for minimizing movement of the cervical spine during endotracheal intubation
.
Anesthesiology
 
2009
;
110
:
1335
40
150
Rai
MR
.
The humble bougie … forty years and still counting?
Anaesthesia
 
2014
;
69
:
199
203
151
Cook
TM
.
A new practical classification of laryngeal view
.
Anaesthesia
 
2000
;
55
:
274
9
152
Yentis
SM
Lee
DJ
.
Evaluation of an improved scoring system for the grading of direct laryngoscopy
.
Anaesthesia
 
1998
;
53
:
1041
4
153
Marson
BA
Anderson
E
Wilkes
AR
Hodzovic
I
.
Bougie-related airway trauma: dangers of the hold-up sign
.
Anaesthesia
 
2014
;
69
:
219
23
154
Arndt
GA
Cambray
AJ
Tomasson
J
.
Intubation bougie dissection of tracheal mucosa and intratracheal airway obstruction
.
Anesth Analg
 
2008
;
107
:
603
4
155
Evans
H
Hodzovic
I
Latto
IP
.
Tracheal tube introducers: choose and use with care
.
Anaesthesia
 
2010
;
65
:
859
156
Kidd
JF
Dyson
A
Latto
IP
.
Successful difficult intubation. Use of the gum elastic bougie
.
Anaesthesia
 
1988
;
43
:
437
8
157
Batra
R
Dhir
R
Sharma
S
Kumar
K
.
Inadvertent pneumothorax caused by intubating bougie
.
J Anaesthesiol Clin Pharmacol
 
2015
;
31
:
271
158
Staikou
C
Mani
AA
Fassoulaki
AG
.
Airway injury caused by a Portex single-use bougie
.
J Clin Anesth
 
2009
;
21
:
616
7
159
Simpson
JA
Duffy
M
.
Airway injury and haemorrhage associated with the Frova intubating introducer
.
J Intensive Care Soc
 
2012
;
13
:
151
4
160
Turkstra
TP
Harle
CC
Armstrong
KP
et al
The GlideScope-specific rigid stylet and standard malleable stylet are equally effective for GlideScope use
.
Can J Anaesth
 
2007
;
54
:
891
6
161
Cooper
RM
Pacey
JA
Bishop
MJ
McCluskey
SA
.
Early clinical experience with a new videolaryngoscope (GlideScope) in 728 patients
.
Can J Anaesth
 
2005
;
52
:
191
8
162
Batuwitage
B
McDonald
A
Nishikawa
K
Lythgoe
D
Mercer
S
Charters
P
.
Comparison between bougies and stylets for simulated tracheal intubation with the C-MAC D-blade videolaryngoscope
.
Eur J Anaesthesiol
 
2015
;
32
:
400
5
163
Cooper
RM
.
Complications associated with the use of the GlideScope videolaryngoscope
.
Can J Anaesth
 
2007
;
54
:
54
7
164
Cross
P
Cytryn
J
Cheng
KK
.
Perforation of the soft palate using the GlideScope videolaryngoscope
.
Can J Anaesth
 
2007
;
54
:
588
9
165
Amundson
AW
Weingarten
TN
.
Traumatic GlideScope® video laryngoscopy resulting in perforation of the soft palate
.
Can J Anaesth
 
2013
;
60
:
210
1
166
Choo
MKF
Yeo
VST
See
JJ
.
Another complication associated with videolaryngoscopy
.
Can J Anaesth
 
2007
;
54
:
322
4
167
Dupanovic
M
.
Maneuvers to prevent oropharyngeal injury during orotracheal intubation with the GlideScope video laryngoscope
.
J Clin Anesth
 
2010
;
22
:
152
4
168
AAGBI Recommendations for standards of monitoring during anaesthesia and recovery 2007 (4th Edn)
.
169
Petrini
F
Accorsi
A
Adrario
E
et al
Recommendations for airway control and difficult airway management
.
Minerva Anestesiol
 
2005
;
71
:
617
57
170
Kristensen
MS
.
Ultrasonography in the management of the airway
.
Acta Anaesthesiol Scand
 
2011
;
55
:
1155
73
171
Kristensen
MS
Teoh
WH
Graumann
O
Laursen
CB
.
Ultrasonography for clinical decision-making and intervention in airway management: from the mouth to the lungs and pleurae
.
Insights Imaging
 
2014
;
5
:
253
79
172
Davies
PRF
Tighe
SQM
Greenslade
GL
Evans
GH
.
Laryngeal mask airway and tracheal tube insertion by unskilled personnel
.
Lancet
 
1990
;
336
:
977
9
173
Muller
NV
Alberts
AA
.
Unique™ Laryngeal Mask airway versus Cobra™ Perilaryngeal airway: learning curves for insertion
.
South Afr J Anaesth Analg
 
2014
;
12
:
21
174
Lopez-Gil
M
Brimacombe
J
Cebrian
J
Arranz
J
.
Laryngeal mask airway in pediatric practice: a prospective study of skill acquisition by anesthesia residents
.
Anesthesiology
 
1996
;
84
:
807
11
175
Brimacombe
J
.
Analysis of 1500 laryngeal mask uses by one anaesthetist in adults undergoing routine anaesthesia
.
Anaesthesia
 
1996
;
51
:
76
80
176
Greaves
JD
.
Training time and consultant practice
.
Br J Anaesth
 
2005
;
95
:
581
3
177
Asai
T
Barclay
K
Power
I
Vaughan
RS
.
Cricoid pressure and the LMA: efficacy and interpretation
.
Br J Anaesth
 
1994
;
73
:
863
4
178
Brimacombe
J
.
Difficult Airway
. In:
Brimacombe J
, ed.
Laryngeal Mask Anesthesia Principles and Practice
 ,
2nd Edn
.
Philadelphia
:
Saunders
,
2005
;
305
56
179
Hashimoto
Y
Asai
T
Arai
T
Okuda
Y
.
Effect of cricoid pressure on placement of the I-gel™: a randomised study
.
Anaesthesia
 
2014
;
69
:
878
82
180
Asai
T
Goy
RWL
Liu
EHC
.
Cricoid pressure prevents placement of the laryngeal tube and laryngeal tube-suction II
.
Br J Anaesth
 
2007
;
99
:
282
5
181
Li
CW
Xue
FS
Xu
YC
et al
Cricoid pressure impedes insertion of, and ventilation through, the ProSeal laryngeal mask airway in anesthetized, paralyzed patients
.
Anesth Analg
 
2007
;
104
:
1195
8
182
Cook
TM
Kelly
FE
.
Time to abandon the ‘vintage’ laryngeal mask airway and adopt second-generation supraglottic airway devices as first choice
.
Br J Anaesth
 
2015
;
115
:
497
9
183
Brain
AIJ
Verghese
C
Strube
PJ
.
The LMA ‘ProSeal’—a laryngeal mask with an oesophageal vent
.
Br J Anaesth
 
2000
;
84
:
650
4
184
Levitan
RM
Kinkle
WC
.
Initial anatomic investigations of the I-gel airway: a novel supraglottic airway without inflatable cuff
.
Anaesthesia
 
2005
;
60
:
1022
6
185
Van Zundert
A
Brimacombe
J
.
The LMA Supreme™—a pilot study
.
Anaesthesia
 
2008
;
63
:
209
10
186
Tiefenthaler
W
Eschertzhuber
S
Brimacombe
J
Fricke
E
Keller
C
Kaufmann
M
.
A randomised, non-crossover study of the GuardianCPV™ Laryngeal Mask versus the LMA Supreme™ in paralysed, anaesthetised female patients
.
Anaesthesia
 
2013
;
68
:
600
4
187
Miller
DM
Lavelle
M
.
A streamlined pharynx airway liner: a pilot study in 22 patients in controlled and spontaneous ventilation
.
Anesth Analg
 
2002
;
94
:
759
61
188
Youssef
MMI
Lofty
M
Hammad
Y
Elmenshawy
E
.
Comparative study between LMA-Proseal™ and Air-Q® Blocker for ventilation in adult eye trauma patients
.
Egypt J Anaesth
 
2014
;
30
:
227
33
189
Alexiev
V
Salim
A
Kevin
LG
Laffey
JG
.
An observational study of the Baska® mask: a novel supraglottic airway
.
Anaesthesia
 
2012
;
67
:
640
5
190
Lopez Sala-Blanch
X
Valero
R
Prats
AA
.
Cross-over assessment of the AmbuAuraGain, LMA Supreme New Cuff and Intersurgical I-Gel in fresh cadavers
.
Open J Anesthesiol
 
2014
;
4
:
332
9
191
Mihai
R
Knottenbelt
G
Cook
TM
.
Evaluation of the revised laryngeal tube suction: the laryngeal tube suction II in 100 patients
.
Br J Anaesth
 
2007
;
99
:
734
9
192
Theiler
L
Gutzmann
M
Kleine-Brueggeney
M
Urwyler
N
Kaempfen
B
Greif
R
.
i-gel™ supraglottic airway in clinical practice: a prospective observational multicentre study
.
Br J Anaesth
 
2012
;
109
:
990
5
193
Cook
TM
Gibbison
B
.
Analysis of 1000 consecutive uses of the ProSeal laryngeal mask airway by one anaesthetist at a district general hospital
.
Br J Anaesth
 
2007
;
99
:
436
9
194
Goldmann
K
Hechtfischer
C
Malik
A
Kussin
A
Freisburger
C
.
Use of ProSeal™ laryngeal mask airway in 2114 adult patients: a prospective study
.
Anesth Analg
 
2008
;
107
:
1856
61
195
Yao
WY
Li
SY
Sng
BL
Lim
Y
Sia
AT
.
The LMA Supreme™ in 700 parturients undergoing Cesarean delivery: an observational study
.
Can J Anaesth
 
2012
;
59
:
648
54
196
Cook
TM
Lee
G
Nolan
JP
.
The ProSeal™ laryngeal mask airway: a review of the literature
.
Can J Anaesth
 
2005
;
52
:
739
60
197
De Montblanc
J
Ruscio
L
Mazoit
JX
Benhamou
D
.
A systematic review and meta-analysis of the i-gel® vs laryngeal mask airway in adults
.
Anaesthesia
 
2014
;
69
:
1151
62
198
Maitra
S
Khanna
P
Baidya
DK
.
Comparison of laryngeal mask airway Supreme and laryngeal mask airway Pro-Seal for controlled ventilation during general anaesthesia in adult patients: systematic review with meta-analysis
.
Eur J Anaesthesiol
 
2014
;
31
:
266
73
199
Park
SK
Choi
GJ
Choi
YS
Ahn
EJ
Kang
H
.
Comparison of the i-gel and the laryngeal mask airway proseal during general anesthesia: a systematic review and meta-analysis
.
PLoS One
 
2015
;
10
:
e0119469
200
Chen
X
Jiao
J
Cong
X
Liu
L
Wu
X
.
A comparison of the performance of the I-gel™ vs. the LMA-S™ during anesthesia: a meta-analysis of randomized controlled trials
.
PLoS One
 
2013
;
8
:
e71910
201
López
AM
Valero
R
Hurtado
P
Gambús
P
Pons
M
Anglada
T
.
Comparison of the LMA Supreme™ with the LMA Proseal™ for airway management in patients anaesthetized in prone position
.
Br J Anaesth
 
2011
;
107
:
265
71
202
Seet
E
Rajeev
S
Firoz
T
et al
Safety and efficacy of laryngeal mask airway Supreme versus laryngeal mask airway ProSeal: a randomized controlled trial
.
Eur J Anaesthesiol
 
2010
;
27
:
602
7
203
Hosten
T
Gurkan
Y
Ozdamar
D
Tekin
M
Toker
K
Solak
M
.
A new supraglottic airway device: LMA-Supreme™, comparison with LMA-Proseal™
.
Acta Anaesthesiol Scand
 
2009
;
53
:
852
7
204
Lee
AKY
Tey
JBL
Lim
Y
Sia
ATH
.
Comparison of the single-use LMA Supreme with the reusable ProSeal LMA for anaesthesia in gynaecological laparoscopic surgery
.
Anaesth Intensive Care
 
2009
;
37
:
815
9
205
Eschertzhuber
S
Brimacombe
J
Hohlrieder
M
Keller
C
.
The Laryngeal Mask Airway Supreme™—a single use laryngeal mask airway with an oesophageal vent. A randomised, cross-over study with the Laryngeal Mask Airway ProSeal™ in paralysed, anaesthetised patients
.
Anaesthesia
 
2009
;
64
:
79
83
206
Singh
I
Gupta
M
Tandon
M
.
Comparison of clinical performance of I-gel with LMA-ProSeal in elective surgeries
.
Indian J Anaesth
 
2009
;
53
:
302
5
207
Chauhan
G
Nayar
P
Seth
A
Gupta
K
Panwar
M
Agrawal
N
.
Comparison of clinical performance of the I-gel with LMA Proseal
.
J Anaesthesiol Clin Pharmacol
 
2013
;
29
:
56
60
208
Mukadder
S
Zekine
B
Erdogan
KG
et al
Comparison of the proseal, supreme, and i-gel SAD in gynecological laparoscopic surgeries
.
Scientific World J
 
2015
;
2015
:
634320
209
Schmidbauer
W
Bercker
S
Volk
T
Bogusch
G
Mager
G
Kerner
T
.
Oesophageal seal of the novel supralaryngeal airway device I-Gel™ in comparison with the laryngeal mask airways Classic™ and ProSeal™ using a cadaver model
.
Br J Anaesth
 
2009
;
102
:
135
9
210
Schmidbauer
W
Genzwürker
H
Ahlers
O
Proquitte
H
Kerner
T
.
Cadaver study of oesophageal insufflation with supraglottic airway devices during positive pressure ventilation in an obstructed airway
.
Br J Anaesth
 
2012
;
109
:
454
8
211
Russo
SG
Cremer
S
Galli
T
et al
Randomized comparison of the i-gel™, the LMA Supreme™, and the Laryngeal Tube Suction-D using clinical and fibreoptic assessments in elective patients
.
BMC Anesthesiol
 
2012
;
12
:
18
212
Shin
W-J
Cheong
Y-S
Yang
H-S
Nishiyama
T
.
The supraglottic airway I-gel in comparison with ProSeal laryngeal mask airway and classic laryngeal mask airway in anaesthetized patients
.
Eur J Anaesthesiol
 
2010
;
27
:
598
601
213
Teoh
WHL
Lee
KM
Suhitharan
T
Yahaya
Z
Teo
MM
Sia
ATH
.
Comparison of the LMA Supreme vs the i-gel™ in paralysed patients undergoing gynaecological laparoscopic surgery with controlled ventilation
.
Anaesthesia
 
2010
;
65
:
1173
9
214
Ragazzi
R
Finessi
L
Farinelli
I
Alvisi
R
Volta
CA
.
LMA Supreme™ vs i-gel™—a comparison of insertion success in novices
.
Anaesthesia
 
2012
;
67
:
384
8
215
Kang
F
Li
J
Chai
X
Yu
J-G
Zhang
H-M
Tang
C-L
.
Comparison of the I-gel laryngeal mask airway with the LMA-Supreme for airway management in patients undergoing elective lumbar vertebral surgery
.
J Neurosurg Anesthesiol
 
2015
;
27
:
37
41
216
Theiler
LG
Kleine-Brueggeney
M
Kaiser
D
et al
Crossover comparison of the laryngeal mask supreme and the i-gel in simulated difficult airway scenario in anesthetized patients
.
Anesthesiology
 
2009
;
111
:
55
62
217
Pajiyar
AK
Wen
Z
Wang
H
Ma
L
Miao
L
Wang
G
.
Comparisons of clinical performance of Guardian laryngeal mask with laryngeal mask airway ProSeal
.
BMC Anesthesiol
 
2015
;
15
:
69
218
Genzwuerker
HV
Altmayer
S
Hinkelbein
J
Gernoth
C
Viergutz
T
Ocker
H
.
Prospective randomized comparison of the new Laryngeal Tube Suction LTS II and the LMA-ProSeal for elective surgical interventions
.
Acta Anaesthesiol Scand
 
2007
;
51
:
1373
7
219
Jeon
WJ
Cho
SY
Baek
SJ
Kim
KH
.
Comparison of the Proseal LMA and intersurgical I-gel during gynecological laparoscopy
.
Korean J Anesthesiol
 
2012
;
63
:
510
4
220
Sharma
B
Sehgal
R
Sahai
C
Sood
J
.
PLMA vs. I-gel: a comparative evaluation of respiratory mechanics in laparoscopic cholecystectomy
.
J Anaesthesiol Clin Pharmacol
 
2010
;
26
:
451
7
221
Van Zundert
TCRV
Brimacombe
JR
.
Similar oropharyngeal leak pressures during anaesthesia with i-gel, LMA-ProSeal and LMA-Supreme Laryngeal Masks
.
Acta Anaesthesiol Belg
 
2012
;
63
:
35
41
222
Chew
EEF
Hashim
NHM
Wang
CY
.
Randomised comparison of the LMA Supreme with the I-Gel in spontaneously breathing anaesthetised adult patients
.
Anaesth Intensive Care
 
2010
;
38
:
1018
22
223
Joly
N
Poulin
L-P
Tanoubi
I
Drolet
P
Donati
F
St-Pierre
P
.
Randomized prospective trial comparing two supraglottic airway devices: i-gel™ and LMA-Supreme™ in paralyzed patients
.
Can J Anaesth
 
2014
;
61
:
794
800
224
Cook
TM
Cranshaw
J
.
Randomized crossover comparison of ProSeal Laryngeal Mask Airway with Laryngeal Tube Sonda during anaesthesia with controlled ventilation
.
Br J Anaesth
 
2005
;
95
:
261
6
225
Kristensen
MS
Teoh
WH
Asai
T
.
Which supraglottic airway will serve my patient best?
Anaesthesia
 
2014
;
69
:
1189
92
226
Alexiev
V
Ochana
A
Abdelrahman
D
et al
Comparison of the Baska® mask with the single-use laryngeal mask airway in low-risk female patients undergoing ambulatory surgery
.
Anaesthesia
 
2013
;
68
:
1026
32
227
Ramachandran
SK
Mathis
MR
Tremper
KK
Shanks
AM
Kheterpal
S
.
Predictors and clinical outcomes from failed Laryngeal Mask Airway UniqueTM: a study of 15,795 patients
.
Anesthesiology
 
2012
;
116
:
1217
26
228
Saito
T
Liu
W
Chew
STH
Ti
LK
.
Incidence of and risk factors for difficult ventilation via a supraglottic airway device in a population of 14 480 patients from South-East Asia
.
Anaesthesia
 
2015
;
70
:
1079
83
229
Howath
A
Brimacombe
J
Keller
C
.
Gum-elastic bougie-guided insertion of the ProSeal laryngeal mask airway: a new technique
.
Anaesth Intensive Care
 
2002
;
30
:
624
7
230
Taneja
S
Agarwalt
M
Dali
JS
Agrawal
G
.
Ease of Proseal Laryngeal Mask Airway insertion and its fibreoptic view after placement using Gum Elastic Bougie: a comparison with conventional techniques
.
Anaesth Intensive Care
 
2009
;
37
:
435
40
231
Brimacombe
J
Keller
C
Judd
DV
.
Gum elastic bougie-guided insertion of the ProSeal laryngeal mask airway is superior to the digital and introducer tool techniques
.
Anesthesiology
 
2004
;
100
:
25
9
232
El Beheiry
H
Wong
J
Nair
G
et al
Improved esophageal patency when inserting the ProSeal laryngeal mask airway with an Eschmann tracheal tube introducer
.
Can J Anaesth
 
2009
;
56
:
725
32
233
Eschertzhuber
S
Brimacombe
J
Hohlrieder
M
Stadlbauer
KH
Keller
C
.
Gum elastic bougie-guided insertion of the ProSeal laryngeal mask airway is superior to the digital and introducer tool techniques in patients with simulated difficult laryngoscopy using a rigid neck collar
.
Anesth Analg
 
2008
;
107
:
1253
6
234
Gasteiger
L
Brimacombe
J
Perkhofer
D
Kaufmann
M
Keller
C
.
Comparison of guided insertion of the LMA ProSeal vs the i-gel?
Anaesthesia
 
2010
;
65
:
913
6
235
Halaseh
BK
Sukkar
ZF
Hassan
LH
Sia
AT
Bushnaq
WA
Adarbeh
H
.
The use of ProSeal laryngeal mask airway in caesarean section—experience in 3000 cases
.
Anaesth Intensive Care
 
2010
;
38
:
1023
8
236
Proseal LMA Instruction Manual
.
Available from https://www.lmana.com/viewifu.php?ifu=19 (accessed 1 August 2014)
237
Caponas
G
.
Intubating laryngeal mask airway
.
Anaesth Intensive Care
 
2002
;
30
:
551
69
238
Ferson
DZ
Rosenblatt
WH
Johansen
MJ
Osborn
I
Ovassapian
A
.
Use of the intubating LMA-Fastrach in 254 patients with difficult-to-manage airways
.
Anesthesiology
 
2001
;
95
:
1175
81
239
Pandit
JJ
MacLachlan
K
Dravid
RM
Popat
MT
.
Comparison of times to achieve tracheal intubation with three techniques using the laryngeal or intubating laryngeal mask airway
.
Anaesthesia
 
2002
;
57
:
128
32
240
Joo
HS
Kapoor
S
Rose
DK
Naik
VN
.
The intubating laryngeal mask airway after induction of general anesthesia versus awake fiberoptic intubation in patients with difficult airways
.
Anesth Analg
 
2001
;
92
:
1342
6
241
Ruxton
L
.
Fatal accident enquiry 15 into the death of Mr Gordon Ewing
.
2010
.
Glasgow: April. Available from https://www.scotcourts.gov.uk/opinions/2010FAI15.html (accessed 14 April 2014)
242
Halwagi
AE
Massicotte
N
Lallo
A
et al
Tracheal intubation through the I-gel™ supraglottic airway versus the LMA Fastrach™: a randomized controlled trial
.
Anesth Analg
 
2012
;
114
:
152
6
243
Theiler
L
Kleine-Brueggeney
M
Urwyler
N
Graf
T
Luyet
C
Greif
R
.
Randomized clinical trial of the i-gel™ and Magill tracheal tube or single-use ILMA™ and ILMA™ tracheal tube for blind intubation in anaesthetized patients with a predicted difficult airway
.
Br J Anaesth
 
2011
;
107
:
243
50
244
Bakker
EJ
Valkenburg
M
Galvin
EM
.
Pilot study of the air-Q intubating laryngeal airway in clinical use
.
Anaesth Intensive Care
 
2010
;
38
:
346
8
245
McAleavey
F
Michalek
P
.
Aura-i laryngeal mask as a conduit for elective fibreoptic intubation
.
Anaesthesia
 
2010
;
65
:
1151
246
Danha
RF
Thompson
JL
Popat
MT
Pandit
JJ
.
Comparison of fibreoptic-guided orotracheal intubation through classic and single-use laryngeal mask airways
.
Anaesthesia
 
2005
;
60
:
184
8
247
Campbell
J
Michalek
P
Deighan
M
.
I-gel supraglottic airway for rescue airway management and as a conduit for tracheal intubation in a patient with acute respiratory failure
.
Resuscitation
 
2009
;
80
:
963
248
Wong
DT
Yang
JJ
Mak
HY
Jagannathan
N
.
Use of intubation introducers through a supraglottic airway to facilitate tracheal intubation: a brief review
.
Can J Anaesth
 
2012
;
59
:
704
15
249
Shimizu
M
Yoshikawa
N
Yagi
Y
et al
[Fiberoptic-guided tracheal intubation through the i-gel supraglottic airway]
.
Masui
 
2014
;
63
:
841
5
250
Kleine-Brueggeney
M
Theiler
L
Urwyler
N
Vogt
A
Greif
R
.
Randomized trial comparing the i-gel™ and Magill tracheal tube with the single-use ILMA™ and ILMA™ tracheal tube for fibreoptic-guided intubation in anaesthetized patients with a predicted difficult airway
.
Br J Anaesth
 
2011
;
107
:
251
7
251
Darlong
V
Biyani
G
Baidya
DK
Pandey
R
Punj
J
.
Air-Q blocker: a novel supraglottic airway device for patients with difficult airway and risk of aspiration
.
J Anaesthesiol Clin Pharmacol
 
2014
;
30
:
589
90
252
Ott
T
Fischer
M
Limbach
T
Schmidtmann
I
Piepho
T
Noppens
RR
.
The novel intubating laryngeal tube (iLTS-D) is comparable to the intubating laryngeal mask (Fastrach) – a prospective randomised manikin study
.
Scand J Trauma Resusc Emerg Med
 
2015
;
23
:
44
253
Atherton
DP
O'Sullivan
E
Lowe
D
Charters
P
.
A ventilation-exchange bougie for fibreoptic intubations with the laryngeal mask airway
.
Anaesthesia
 
1996
;
51
:
1123
6
254
Fibreoptic guided tracheal intubation through aintree intubation catheter
.
255
Berkow
LC
Schwartz
JM
Kan
K
Corridore
M
Heitmiller
ES
.
Use of the Laryngeal Mask Airway-Aintree Intubating Catheter-fiberoptic bronchoscope technique for difficult intubation
.
J Clin Anesth
 
2011
;
23
:
534
9
256
Cook
TM
Silsby
J
Simpson
TP
.
Airway rescue in acute upper airway obstruction using a ProSeal Laryngeal mask airway and an Aintree Catheter: a review of the ProSeal Laryngeal mask airway in the management of the difficult airway
.
Anaesthesia
 
2005
;
60
:
1129
36
257
Cook
TM
Seller
C
Gupta
K
Thornton
M
O'Sullivan
E
.
Non-conventional uses of the Aintree Intubating Catheter in management of the difficult airway
.
Anaesthesia
 
2007
;
62
:
169
74
258
Izakson
A
Cherniavsky
G
Lazutkin
A
Ezri
T
.
The i-gel as a conduit for the Aintree intubation catheter for subsequent fiberoptic intubation Case description
.
Rom J Anaesth Intensive Care
 
2014
;
21
:
131
3
259
Van Zundert
TC
Wong
DT
Van Zundert
AA
.
The LMA-SupremeTM as an intubation conduit in patients with known difficult airways: a prospective evaluation study
.
Acta Anaesthesiol Scand
 
2013
;
57
:
77
81
260
Greenland
KB
Tan
H
Edwards
M
.
Intubation via a laryngeal mask airway with an Aintree catheter - not all laryngeal masks are the same
.
Anaesthesia
 
2007
;
62
:
966
7
261
Baker
PA
Flanagan
BT
Greenland
KB
et al
Equipment to manage a difficult airway during anaesthesia
.
Anaesth Intensive Care
 
2011
;
39
:
16
34
262
Michael Harmer
.
The Case of Elaine Bromiley
.
263
Desforges
JCW
McDonnell
NJ
.
Sugammadex in the management of a failed intubation in a morbidly obese patient
.
Anaesth Intensive Care
 
2011
;
39
:
763
4
264
Mendonca
C
.
Sugammadex to rescue a ‘can't ventilate’ scenario in an anticipated difficult intubation: is it the answer?
Anaesthesia
 
2013
;
68
:
795
9
265
Barbosa
FT
da Cunha
RM
.
Reversal of profound neuromuscular blockade with sugammadex after failure of rapid sequence endotracheal intubation: a case report
.
Rev Bras Anestesiol
 
2012
;
62
:
281
4
266
Curtis
RP
.
Persistent ‘can't intubate, can't oxygenate’ crisis despite reversal of rocuronium with sugammadex: the importance of timing
.
Anaesth Intensive Care
 
2012
;
40
:
722
267
Langvad
S
Hyldmo
PK
Nakstad
AR
Vist
GE
Sandberg
M
.
Emergency cricothyrotomy – a systematic review
.
Scand J Trauma Resusc Emerg Med
 
2013
;
21
:
43
268
Heard
A
.
Percutaneous Emergency Oxygenation Strategies in the ‘Can't Intubate, Can't Oxygenate’ Scenario
.
Smashworks Editions;
2013
.
Available from https://www.smashwords.com/books/view/377530 (accessed 5 January 2014)
269
Lockey
D
Crewdson
K
Weaver
A
Davies
G
.
Observational study of the success rates of intubation and failed intubation airway rescue techniques in 7256 attempted intubations of trauma patients by pre-hospital physicians
.
Br J Anaesth
 
2014
;
113
:
220
5
270
Mabry
RL
Nichols
MC
Shiner
DC
Bolleter
S
Frankfurt
A
.
A comparison of two open surgical cricothyroidotomy techniques by military medics using a cadaver model
.
Ann Emerg Med
 
2014
;
63
:
1
5
271
Pugh
HE
LeClerc
S
Mclennan
J
.
A review of pre-admission advanced airway management in combat casualties, Helmand Province 2013
.
J R Army Med Corps
 
2015
;
161
:
121
6
272
Howes
TE
Lobo
CA
Kelly
FE
Cook
TM
.
Rescuing the obese or burned airway: are conventional training manikins adequate? A simulation study
.
Br J Anaesth
 
2015
;
114
:
136
42
273
Kristensen
MS
Teoh
WH
Baker
PA
.
Percutaneous emergency airway access; prevention, preparation, technique and training
.
Br J Anaesth
 
2015
;
114
:
357
61
274
Hamaekers
AE
Henderson
JJ
.
Equipment and strategies for emergency tracheal access in the adult patient
.
Anaesthesia
 
2011
;
66
:
65
80
275
Crewdson
K
Lockey
DJ
.
Needle, knife, or device – which choice in an airway crisis?
Scand J Trauma Resusc Emerg Med
 
2013
;
21
:
49
276
Wong
DT
Prabhu
AJ
Coloma
M
Imasogie
N
Chung
FF
.
What is the minimum training required for successful cricothyroidotomy? A study in mannequins
.
Anesthesiology
 
2003
;
98
:
349
53
277
Hubert
V
Duwat
A
Deransy
R
Mahjoub
Y
Dupont
H
.
Effect of simulation training on compliance with difficult airway management algorithms, technical ability, and skills retention for emergency cricothyrotomy
.
Anesthesiology
 
2014
;
120
:
999
1008
278
Hubble
MW
Wilfong
DA
Brown
LH
Hertelendy
A
Benner
RW
.
A meta-analysis of prehospital airway control techniques part II: alternative airway devices and cricothyrotomy success rates
.
Prehosp Emerg Care
 
2010
;
14
:
515
30
279
Baker
PA
Weller
JM
Greenland
KB
Riley
RH
Merry
AF
.
Education in airway management
.
Anaesthesia
 
2011
;
66
(Suppl 2)
:
101
11
280
Mabry
RL
.
An analysis of battlefield cricothyrotomy in Iraq and Afghanistan
.
J Spec Oper Med
 
2012
;
12
:
17
23
281
Levitan
RM
.
Cricothyrotomy | Airway Cam - Airway Management Education and Training
.
Available from http://www.airwaycam.com/cricothyrotomy (accessed 4 August 2015)
282
Airway and ventilatory management
. In:
Douglas
P
, ed.
ATLS® Guidelines 9th Ed Kindle edition
 .
Chicago
:
The American College of Surgeons
,
2012
283
Brofeldt
BT
Panacek
EA
Richards
JR
.
An easy cricothyrotomy approach: the rapid four-step technique
.
Acad Emerg Med
 
1996
;
3
:
1060
3
284
Ross-Anderson
DJ
Ferguson
C
Patel
A
.
Transtracheal jet ventilation in 50 patients with severe airway compromise and stridor
.
Br J Anaesth
 
2011
;
106
:
140
4
285
Bourgain
JL
.
Transtracheal high frequency jet ventilation for endoscopic airway surgery: a multicentre study
.
Br J Anaesth
 
2001
;
87
:
870
5
286
Craven
RM
Vanner
RG
.
Ventilation of a model lung using various cricothyrotomy devices
.
Anaesthesia
 
2004
;
59
:
595
9
287
Heard
A
.
Instructor Check-lists for Percutaneous Emergency Oxygenation Strategies in the ‘Can't Intubate, Can't Oxygenate’ Scenario 2014
.
Available from https://www.smashwords.com/books/view/494739 (accessed 23 April 2015)
288
Heard
AMB
Green
RJ
Eakins
P
.
The formulation and introduction of a ‘can't intubate, can't ventilate’ algorithm into clinical practice
.
Anaesthesia
 
2009
;
64
:
601
8
289
Melker
JS
Gabrielli
A
.
Melker Cricothyrotomy Kit: an alternative to the surgical technique
.
Ann Otol Rhinol Laryngol
 
2005
;
114
:
525
8
290
Kristensen
MS
Teoh
WH
Rudolph
SS
et al
Structured approach to ultrasound-guided identification of the cricothyroid membrane: a randomized comparison with the palpation method in the morbidly obese
.
Br J Anaesth
 
2015
;
114
:
1003
4
291
Kleine-Brueggeney
M
Greif
R
Ross
S
et al
Ultrasound-guided percutaneous tracheal puncture: a computer-tomographic controlled study in cadavers
.
Br J Anaesth
 
2011
;
106
:
738
42
292
Dinsmore
J
Heard
AMB
Green
RJ
.
The use of ultrasound to guide time-critical cannula tracheotomy when anterior neck airway anatomy is unidentifiable
.
Eur J Anaesthesiol
 
2011
;
28
:
506
10
293
Mallin
M
Curtis
K
Dawson
M
Ockerse
P
Ahern
M
.
Accuracy of ultrasound-guided marking of the cricothyroid membrane before simulated failed intubation
.
Am J Emerg Med
 
2014
;
32
:
61
3
294
World Alliance for Patient Safety
.
WHO Guidelines for Safe Surgery
 .
Geneva
:
World Health Organization
,
2008
295
Apfelbaum
JL
Hagberg
CA
Caplan
RA
et al
Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway
.
Anesthesiology
 
2013
;
118
:
251
70
296
Feinleib
J
Foley
L
Mark
L
.
What we all should know about our patient's airway: difficult airway communications, database registries, and reporting systems registries
.
Anesthesiol Clin
 
2015
;
33
:
397
413
297
Hagberg
C
Georgi
R
Krier
C
.
Complications of managing the airway
.
Best Pract Res Clin Anaesthesiol
 
2005
;
19
:
641
59
298
Domino
KB
Posner
KL
Caplan
RA
Cheney
FW
.
Airway injury during anesthesia: a closed claims analysis
.
J Am Soc Anesthesiol
 
1999
;
91
:
1703
299
Woodall
NM
Harwood
RJ
Barker
GL
.
Complications of awake fibreoptic intubation without sedation in 200 healthy anaesthetists attending a training course
.
Br J Anaesth
 
2008
;
100
:
850
5
300
Gamlin
F
Caldicott
LD
Shah
MV
.
Mediastinitis and sepsis syndrome following intubation
.
Anaesthesia
 
1994
;
49
:
883
5
301
Barron
FA
Ball
DR
Jefferson
P
Norrie
J
.
‘Airway Alerts’. How UK anaesthetists organise, document and communicate difficult airway management
.
Anaesthesia
 
2003
;
58
:
73
7
302
Mellado
PF
Thunedborg
LP
Swiatek
F
Kristensen
MS
.
Anaesthesiological airway management in Denmark: assessment, equipment and documentation
.
Acta Anaesthesiol Scand
 
2004
;
48
:
350
4
303
Wilkes
M
Beattie
C
Gardner
C
McNarry
AF
.
Difficult airway communication between anaesthetists and general practitioners
.
Scott Med J
 
2013
;
58
:
2
6
304
Baker
P
Moore
C
Hopley
L
Herzer
K
Mark
L
.
How do anaesthetists in New Zealand disseminate critical airway information?
Anaesth Intensive Care
 
2013
;
41
:
334
41
305
Difficult Airway Society
.
Airway Alert Form
.
Available from http://www.das.uk.com/guidelines/airwayalert.html (accessed 4 August 2015)
306
Liban
JB
.
Medic Alert UK should start new section for patients with a difficult airway
.
Br Med J
 
1996
;
313
:
425
307
Medical Alert
.
Available from https://www.medicalert.org.uk/ (accessed 4 August 2015)
308
Banks
IC
.
The application of Read Codes to anaesthesia
.
Anaesthesia
 
1994
;
49
:
324
7
309
Law
JA
Broemling
N
Cooper
RM
et al
The difficult airway with recommendations for management – Part 1 – Intubation encountered in an unconscious/induced patient
.
Can J Anaesth
 
2013
;
60
:
1089
118
310
Teoh
WHL
Shah
MK
Sia
ATH
.
Randomised comparison of Pentax AirwayScope and Glidescope for tracheal intubation in patients with normal airway anatomy
.
Anaesthesia
 
2009
;
64
:
1125
9
311
Hoshijima
H
Kuratani
N
Hirabayashi
Y
Takeuchi
R
Shiga
T
Masaki
E
.
Pentax Airway Scope® vs Macintosh laryngoscope for tracheal intubation in adult patients: a systematic review and meta-analysis
.
Anaesthesia
 
2014
;
69
:
911
8
312
Behringer
EC
Cooper
RM
Luney
S
Osborn
IP
.
The comparative study of video laryngoscopes to the Macintosh laryngoscope: defining proficiency is critical
.
Eur J Anaesthesiol
 
2012
;
29
:
158
9
313
Behringer
EC
Kristensen
MS
.
Evidence for benefit vs novelty in new intubation equipment
.
Anaesthesia
 
2011
;
66
(Suppl 2)
:
57
64
314
The Royal College of Anaesthetists CPD Matrix
.
Available from http://www.rcoa.ac.uk/document-store/cpd-matrix (accessed 4 August 2015)

Author notes

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com

Comments

19 Comments
2015 DAS guidelines: the end for pre-paralysis mask ventilation check?
13 December 2015
Richard A Stewart

Dear Sir,

I read with interest the article by C.Frerk et al outlining the new Difficult Airway Society (DAS) guidelines for the management of unanticipated difficult intubation in adults and the accompanying rationale for their implementation. I wholeheartedly support the simplified and didactic nature of the guidelines and agree that, in times of extreme stress, clinicians need fewer recommendations to consider, not more.

One could not help but notice, however, a thread that may radically alter the way we all induce anaesthesia and teach our trainees to do so.

Following the new guidelines through to their logical conclusion in each scenario, the requirement for adequate neuromuscular blockade (NMB) is deemed essential at every step. This may seem counterintuitive to many as to preclude the option of 'bailing out' and waking the patient up in the event of failure to oxygenate. The 2015 guidelines only guide the clinician to wake the patient up after an adequate airway and oxygenation have been established, and in order to achieve this, NMB is advised throughout.

If this approach is to be adopted, one should ask- if, as things get more fraught and the oxygen saturation tone gets lower, I am being asked to give more NMB agent, why wouldn't I just administer it to the patient as early as possible? Doing so would reduce the likelihood of plans B,C and D being required in the first place and also negate the need to consider it again at step C, provided an adequate dose had been given at the outset.

A quick straw poll of the consultants in our department still puts pre-NMB 'checkers' way ahead of 'non-checkers', a view that is further emphasised when they were asked what advice they would pass on to a trainee.

This view is in agreement with both historical and current teaching and one would imagine reflects wider practice however, if universally accepted, the 2015 guidelines may cause us all to re-think the logic of checking mask ventilation before administering NMB, once and for all.

Conflict of Interest:

None declared

Submitted on 13/12/2015 7:00 PM GMT
Reducing mucosal trauma at laryngoscopy
20 December 2015
Richard L Dodwell (with Mark W Davies, Consultant Anaesthetist)

Dear Sir,

We congratulate the authors on their updated guidelines, but wonder if perhaps one simple technique for reducing airway trauma - and at the same time increasing the speed and ease of intubation - has been overlooked.

Whilst it is second nature for our ODPs to surface-lubricate a supraglottic airway device or an Airtraq, the same is rarely true for the curved blade of a Macintosh laryngoscope, which was also designed to slide across airway mucosa.

Use of a dry laryngoscope blade is suboptimal, anachronistic and risks "a wasted attempt".

In keeping with this excellent guidance, we should consider teaching our ODPs to routinely lubricate all mucosal-contact airway devices.

Conflict of Interest:

None declared

Submitted on 20/12/2015 7:00 PM GMT
In response: Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults
21 December 2015
Gaurav S Tomar

Sir,

We read with much interest special article by Frerk et al.[1] about recent updated guidelines on management of unanticipated difficult intubation in adults. Article appears to be very informative and assist in decision making.

The authors described use of scalpel-finger-bougie technique in case of impalpable cricothyroid membrane and narrated midline vertical skin incision of 8-10 cm directed caudad to cephalad. We found 8-10 cm length of incision over trachea to be quite debatable as it can lead to higher risk of bleeding/oozing from the local tissues making poor visualization of landmarks and risk of infection postoperatively. However, it can helps in better palpation of cricothyroid membrane.[2] We suggest the authors acknowledge use of techniques such as infiltration of local anaesthetic along with epinephrine or the standby measures like application of cautery (monopolar/bipolar) to herald bleeding at local site while performing procedure in emergency.

References

1.Frerk CM, Mitchell VS, McNarry AF, et al. Difficult Airway Society 2015 guidelines for the management of unanticipated difficult intubation in adults. Br J Anaesth 2015; 115: 827-48.

2.Bagheri SC, Bryan Bell B, Khan HA. Current therapy in oral and maxillofacial surgery. Elsevier Health Sciences, 2011; pp-276.

Conflict of Interest:

None declared

Submitted on 21/12/2015 7:00 PM GMT
Re:2015 DAS guidelines: the end for pre-paralysis mask ventilation check?
18 January 2016
Christopher M Frerk (with V S Mitchell, AF McNarry, C Mendonca, R Bhagrath, A Patel, EP O'Sullivan, NM Woodall, I Ahmad)

We would like to thank Dr Stewart for his interest in the recently published DAS Guidelines(1) . He has identified an area where there may be much discussion over the coming months.

There is evidence that difficult mask ventilation is associated with difficult tracheal intubation(2,3) and the guidelines highlight the importance of preoperative airway assessment indicating that where difficulty with ventilation or tracheal intubation can be anticipated, strategies other than intravenous induction of anaesthesia and neuromuscular blockade may be more appropriate (eg awake fibreoptic intubation).

The guidelines have been produced to support decision making in the face of unanticipated difficulty with airway management; there is an evidence base for improved mask ventilation following neuromuscular blockade so considering Dr Stewarts comments solely in the situation where the airway has been assessed and no difficulty is anticipated the question we need to ask ourselves is:

If facemask ventilation turns out to be really difficult in an apparently normal patient should I...

a) continue attempts at mask ventilation and plan wake up while awaiting return of spontaneous ventilation? or

b) work through the other steps in the guidelines all of which are likely to be more effective in a paralysed patient?

How we answer this question should determine how we teach our trainees to manage induction of anaesthesia where neuromuscular blockade is part of the airway management strategy.

References

1. Frerk C, Mitchell VS, McNarry AF, et al. Difficult Airway Society intubation guidelines working group. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth 2015; 115: 827-48

2. Norskov AK, Rosenstock C V, Wetterslev J, Astrup G, Afshari A, Lundstrom LH. 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. Anaesthesia 2015; 70: 272-81

3. Kheterpal S, Healy D, Aziz MF, Shanks AM, Freundlich RE, Linton F, et al. Incidence, predictors, and outcome of difficult mask ventilation combined with difficult laryngoscopy: a report from the multicenter perioperative outcomes group. Anesthesiology. 2013 Dec;119:1360-9.

Conflict of Interest:

None declared

Submitted on 18/01/2016 7:00 PM GMT
Re:In response: Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults
18 January 2016
Christopher M Frerk (with V S Mitchell, AF McNarry, C Mendonca, R Bhagrath, A Patel, EP O'Sullivan, NM Woodall, I Ahmad)

Gaurav S Tomar raises interesting points about the didactic approach to emergency front of neck access in the new DAS guidelines.

The guidelines highlight the importance of preoperative airway assessment(1) and where significant difficulty with airway management has been anticipated strategies other than intravenous induction of anaesthesia and neuromuscular blockade may be more appropriate. If cricothyroidotomy is anticipated to be a likely option then we agree that infiltration of local anaesthetic with vasoconstrictor and preparation of equipment such as diathermy is a wise precaution, in this situation we would also recommend calling an ENT surgeon.

The guidelines have been produced to support decision making in the face of unanticipated difficulty with airway management. When plans A to C have failed to maintain oxygenation and the decision has been made to move to plan D, the situation has become time critical. The technique required for accessing the airway through the front of the neck is necessarily different to the way an ENT surgeon would perform an elective or urgent tracheostomy, and needs to provide the anaesthetist with the best chance of restoring oxygenation rapidly.

The recommended 8-10cm vertical incision will increase bleeding, but this is only advocated in patients where the cricothyroid membrane is not palpable or where the default technique (a single transverse stab incision through skin and cricothyroid membrane) has failed. Urgent surgical review of the cricothyroidotomy site (after an airway has been established) is explicitly recommended in the guidelines - in the UK this would usually be undertaken by an ENT surgeon with access to a full set of surgical instruments and ancillary equipment such as diathermy.

References

1. Frerk C, Mitchell VS, McNarry AF, et al. Difficult Airway Society intubation guidelines working group. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth 2015; 115: 827-48

Conflict of Interest:

None declared

Submitted on 18/01/2016 7:00 PM GMT
Atracurium - check, ventilation - check.
18 January 2016
Helen C Bryant (with Torlot, K)

Dear Sir,

The ability to mask ventilate prior to the administration of long- acting neuromuscular blocking agents has been the subject of much debate. Although failed mask ventilation is an uncommon airway event, it has been associated with a difficult intubation in 25% cases in a large observational study [1]. The review panel in the 4th National Audit Project considered that delay or avoidance of neuromuscular blocking drugs (NBDs) contributed to some of the adverse events reported to them [2]. The early administration of NBDs prior to checking mask ventilation is now encouraged [3].

In accordance with the new DAS guidelines [4], sugammadex can be administered for the immediate antagonism of rocuronium or vecuronium in the event of failed intubation where waking the patient up is planned. However, when atracurium is the chosen muscle relaxant and intubation and ventilation fails, the ability to attempt to wake the patient is not an option and commits the patient to emergency front-of-neck access. We think this highlights the importance of clarifying individual practice when administering non-depolarising muscle relaxants. We would argue that check-ventilation should continue where atracurium use is planned. Should ventilation fail, a short-acting or immediately reversible long-acting muscle relaxant could be administered instead to facilitate intubation [5]. This would maintain the potential to wake the patient in line with recent recommendations, should intubation then fail.

References

1. Kheterpal S, Martin L, Shanks AM, Tremper KK. Prediction and outcomes of impossible mask ventilation: a review of 50,000 anesthetics. Anaesthesiology 2009; 110(4):891-7

2. Cook TM, Woodall N and Frerk C. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: Anaesthesia. Br. J. Anaesth 2011; 106(5): 617-31

3. Patel A. Facemask ventilation before or after neuromuscular blocking drugs: where are we now? Anaesthesia 2014; 69 (8): 811-5

4. Frerk C, Mitchell VS, McNarry AF et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br. J. Anaesth. 2015; 115(6): 827-48

5. Pandit JJ. Checking the ability to mask ventilate before administering long-acting neuromuscular blocking drugs. Anaesthesia 2011; 66 (6): 520 - 2

Conflict of Interest:

None declared

Submitted on 18/01/2016 7:00 PM GMT
Plan D: Cannula First, or Scalpel Only?
18 January 2016
Andrew Heard (with James Dinsmore, Scott Douglas, and David Lacquierre)

The Difficult Airway Society (DAS) intubation guidelines working group should be commended for producing their new set of guidelines [1]. There are many aspects of the revised Plans A, B and C which improve upon the 2004 guidelines. However, we have concerns regarding the reasoning behind, and recommendations in, what is in effect a 'scalpel only' Plan D recommendation. It would be convenient if the evidence unequivocally supported the simplification of the CICO pathway as produced but this is not the case. We hope sharing our concerns with the anaesthetic community will facilitate further discussion and lead towards what we would feel is a more rounded Plan D approach.

The DAS guidelines attempt to reduce decision-making in a time- critical CICO scenario. This may remove 'analysis paralysis' [2] and aid transition to performing CICO rescue techniques. However it is also important that this is achieved without limiting options for managing the CICO scenario. For Plan D, DAS acknowledge that the evidence base for choice of technique is limited and "none of these completely replicates the situation faced by anaesthetists delivering general anaesthesia in a hospital setting", acknowledge that "a cricothyroidotomy can be performed using either a scalpel or a cannula technique", but then conclude that anaesthetists should perform a specific (scalpel) technique.

The authors cite the Fourth National Audit Project of the Royal College of Anaesthetist and the Difficult Airway Society (NAP4) [3] as evidence to support their guidance that anaesthetists should now use a scalpel technique. NAP4 actually details that anaesthetists almost exclusively chose cannula techniques and did not attempt scalpel techniques. Surgical airway access was undertaken by surgeons and in the majority of cases they were head and neck specialists. NAP4 does not shed any light on the likely success or not of scalpel techniques carried out by anaesthetists. The high cost of this decision in the 2015 guidelines is that anaesthetists are pressured into going for a single technique, which most would not choose as their preferred option [4,5]. This insistence upon only a scalpel technique may discourage and delay the undertaking of any CICO rescue technique.

Over the last 10 years, we have run weekly training using anaesthetised sheep in a simulated CICO scenario [6,7]. Having observed over 10 000 attempts at performing CICO rescue techniques in this 'wet lab' setting, we have observed that a 'scalpel first' pathway, is in practice, a 'scalpel only' pathway as failed scalpel attempts greatly reduce the success of subsequent cannula attempts: the endpoint of cannula insertion (free aspiration of air) is frequently impeded by soiling of the trachea with blood during the scalpel attempts. However, when conducted with the correct technique and equipment, a failed cannula insertion does not limit the success of subsequent scalpel attempts. An algorithm should aim to achieve the best patient outcome by allowing the anaesthetist to attempt all CICO rescue techniques, from least to most invasive, in a timely manner, in every patient.

We don't believe that the possibility of scalpel-bougie failure is given adequate consideration in the guidelines. The possibility of pre- tracheal bougie insertion is mentioned but other difficulties and complications can occur. Mabry, used as one of three references in support of a scalpel technique, states that 'the scalpel is the fastest and most reliable method of securing the airway in the emergency setting', yet found there was a 32% overall failure rate for scalpel cricothyroidotomy, with complications including incorrect anatomic placement, excessive bleeding and air leak [8]. The reader of the new DAS CICO guideline could be forgiven for thinking that it describes the CICO 'holy grail' of a single technique, suitable for all situations with minimal modification, which will inevitably be successful without complication. Unfortunately, this is not the case.

As a result of our experience in the wet lab we recommend an approach in which a cannula technique is used first prior to transition to a scalpel technique in case of failure with the cannula [6]. A cannula represents less of a mental hurdle for anaesthetists, and produces a route for both rapid reoxygenation and subsequent conversion to a cuffed airway using a Seldinger technique. Use of a cannula also leads to rapid identification of success or indeed failure (failure to aspirate air), the latter facilitating several attempts in a short space of time. Importantly, if the cannula fails after three attempts or 60 seconds, we recommend the anaesthetist then progresses to the scalpel-bougie or scalpel-finger-cannula technique. Failed cannula insertion can be quickly identified and causes less tissue destruction than a failed scalpel attempt.

It is interesting that the change in nomenclature from CICV to CICO has been made in the new guidelines, but does not seem to have been fully appreciated. The adage that achieving a cuffed airway to allow ventilation is the priority remains key to the argument for a scalpel only algorithm. The priority should be achieving oxygen delivery to the patient in the quickest time frame to prevent hypoxic arrest. This can be rapidly achieved via a cannula technique. Ventilation and airway protection are secondary goals that can anyway be achieved via a cannula using the 5.0 Melker.

Historically much of the concern in the literature regarding the safety of cannula techniques focuses on the subsequent process of attempting to 'ventilate' via the cannula using a high pressure oxygen source. Again, it must be emphasised that the priority in a CICO scenario is oxygenation, not ventilation. The article quotes evidence related to outdated approaches that involved attempting to ventilate as opposed to oxygenate via cannula cricothyroidotomy [9], and in the Plan D BJA podcast [10] it is suggested that the Manujet would be the usual oxygen delivery device to be used when performing cannula cricothyroidotomy. We agree with the risks associated with attempting ventilation via a cannula or the use of a Manujet but argue that they don't apply to a safe rescue oxygenation technique using appropriate equipment.

The process of rescue oxygenation via cannulae has been refined in recent years with considerable improvements in safety and efficacy. It is vital that anaesthetists understand that when it comes to emergency oxygenation through a small bore cannula, the Manujet, which was considered the gold standard device for oxygen delivery, has now been superseded. Low-cost flow-regulated oxygen delivery devices are now available that give feedback for obstruction and which enable expiratory flow out of a cannula. This, along with a robust check aspiration technique for identifying correct tracheal placement, and a simple oxygen delivery plan aimed at initially treating hypoxia dramatically improves the safety profile of cannula oxygenation techniques to the extent that we now strongly disagree with the assertion that there is a 'significant risk of barotrauma'.

The scalpel-bougie technique as detailed in the 'cricothyroid membrane palpable: scalpel technique' section of Plan D is a variation of a technique first described by one of our group in 2004, presented at the DAS meeting in Dublin in 2006, and published in 2009 [6]. We are unaware of any human studies of this technique. It should be noted that the three pre-hospital papers quoted by DAS in support of their guidance for scalpel cricothyroidotomy [8,11,12] involve a variety of surgical techniques which are not the same as the scalpel-bougie technique. The implication is that all surgical techniques have equal efficacy in the hands of an anaesthetist. Our experience in the wet lab is that this is not the case.

It should be highlighted to the reader that, with an appropriate technique, the scalpel-bougie technique can be performed through the trachea and not only the cricothyroid membrane. It has been shown that in a significant percentage of CICO events the trachea is palpable even when the cricothyroid membrane is not [13]. A minimally invasive tracheal scalpel- bougie technique is preferable to a long midline incision when the trachea is palpable but the cricothyroid membrane is not. This option is not made evident in the DAS guidelines.

Of interest, no positive "endpoint" to determine successful bougie insertion is described in the technique in the guidelines. It appears correct identification of the airway will only be established after railroading the endotracheal tube and attaching capnography. If the tube is railroaded in a peri-tracheal plane it will result in substantial trauma and bleeding, and substantial delay until identification of a failed attempt. As a minimum, recognition of tracheal "clicks" or bougie hold-up at an appropriate depth (10-15cm) should be sought. Ideally, we would advocate that the patient be re-oxygenated via a Frova bougie using a 15mm Rapi-Fit connector (or similar), attached to the anaesthetic circuit, which also confirms appropriate placement by capnography. This allows for both re-oxygenation and identification of technique failure earlier and with less trauma than waiting for endotracheal tube capnography. Also it is important to accept that railroading of the ETT over the bougie may not always be initially successful, reinforcing the benefit of early delivery of oxygen via the bougie.

Another concern with the 2015 guidelines relates to the recommendation of a 'scalpel-finger-bougie' technique in the patient with an impalpable cricothyroid membrane. In some clinical scenarios airway anatomy maybe impalpable even though it is superficial (eg burns), however in many it will be because the structures are deep due to the volume of pretracheal tissue (eg adipose tissue, blood or goitre.). When we first introduced a deep impalpable neck wet lab model in 2005, it took over six months of trial and error, including ENT surgical input, to establish which technique was achievable by anaesthetists. There were four options considered: percutaneous cannula insertion, Scalpel Finger tube (SFT), Scalpel Finger Cannula (SFC) and Scalpel Finger Scalpel Bougie (SFSB), which the authors of the 2015 guidelines have named 'scalpel-finger- bougie'. We recommend a judicious attempt at percutaneous cannula insertion (3 passes or 60 seconds) even in the impalpable scenario as it aids transition to declaring a CICO, and avoids the need for a deeply invasive open technique if it is successful.

In the cases where a scalpel is required the only technique anaesthetists could reliably and safely perform was the SFC technique. The SFT technique was feasible but required high levels of scalpel control which most anaesthetists could not achieve. The SFSB was excluded because we found it had a high failure rate.

The reason for this failure was twofold. Firstly, (once the trachea had been identified, if possible, by dissection) it required making a difficult incision deep in the neck into the trachea via a narrow cavity rapidly filling with blood. This again (as in the SFT technique) required a high level of precision with a scalpel blade. Manipulating a cannula at the bottom of a blood filled cavity is concerning enough with our SFC technique, but is far more concerning with a SFSB technique.

Secondly, the bougie must be held parallel to the floor (as correctly described by the authors in their paper for scalpel-bougie technique) in order for the coude tip to abut the scalpel blade and slide into the trachea. In a deep trachea scenario, the bougie cannot be held parallel to the floor due to the position of the trachea at the bottom of a 'valley' of neck tissue (see figure). This forces the operator to hold the bougie at a more vertical angle and hence the coude tip does not abut the scalpel blade and does not enter the trachea (which in our live model often cannot be seen due to the blood filling the incision).

We acknowledge that these concerns may not be equally applicable to patients with an impalpable cricothyroid membrane with superficial neck anatomy, but (particularly given the impact of obesity on airway management) we believe the deep neck scenario is highly relevant to clinical practice. We are concerned that the new DAS guidelines recommend a technique that proved ineffective in our wet lab and, to our knowledge, is untested in any other clinical, cadaveric, or large animal appraisal.

In conclusion, given the enormous influence of the DAS guidelines on airway specialists all over the world, if there is any doubt as to what is the "right" choice, then it is not appropriate to promulgate a "no choice" [2] approach. The more appropriate alternative is in fact already eloquently stated in these guidelines. To rephrase the advice on choice of supraglottic airway device, "The decision about which Emergency Front of Neck technique [our substitution] to use should have been made before induction of anaesthesia, and this choice should be determined by the clinical situation, device availability, and operator experience." We believe that with appropriate training and equipment, an integrated cannula first approach to CICO rescue techniques is a valid approach for anaesthetists and their patients, and this should be reflected in the DAS Plan D recommendations.

References

1. Frerk C, Mitchell VS, McNarry AF, et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth 2015; 115: 827-48

2. Greenland, KB. Art of airway management: the concept of 'Ma' (Japanese: ?, when 'less is more'). Br J Anaesth 2015; 115: 809-12

3. 4th National Audit Project of The Royal College of Anaesthetists and The Difficult Airway Society. Major complications of airway management in the United Kingdom, Report and Findings. Royal College of Anaesthetists, London, 2011

4. Wong DT, Lai K, Chung FF, Ho RY. Cannot intubate-cannot ventilate and difficult intubation strategies: results of a Canadian national survey. Anesth Analg 2005; 100: 1439-46

5. Wong DT, Mehta A, Tam AD, Yau B, Wong J. A survey of Canadian anesthesiologists' preferences in difficult intubation and "cannot intubate, cannot ventilate" situations. Can J Anaesth 2014; 61: 717-26

6. Heard A. Percutaneous Emergency Oxygenation Strategies in the 'Can't Intubate, Can't Oxygenate' Scenario. Smashworks Editions; 2013. Available from https://www.smashwords.com/books/view/377530 (accessed 22 December 2015)

7. Heard AMB, Green RJ, Eakins P. The formulation and introduction of a 'can't intubate, can't ventilate' algorithm into clinical practice. Anaesthesia 2009; 64: 601-8

8. Mabry RL. An analysis of battlefield cricothyrotomy in Iraq and Afghanistan. J Spec Oper Med 2012; 12: 17-23

9. Craven RM, Vanner RG. Ventilation of a model lung using various cricothyrotomy devices. Anaesthesia 2004; 59: 595-9

10. DAS unanticipated difficult intubation guidelines 2015; Plan D with Dr Ravi Bhagrath. Available from http://www.oxfordjournals.org/podcasts/bja_115.06.02.mp3 (Accessed 22 December 2015)

11. Lockey D, Crewdson K, Weaver A, Davies G. Observational study of the success rates of intubation and failed intubation airway rescue techniques in 7256 attempted intubations of trauma patients by pre- hospital physicians. Br J Anaesth 2014; 113: 220-5

12. Hubble MW, Wilfong DA, Brown LH, Hertelendy A, Benner RW. A meta- analysis of prehospital airway control techniques part II: alternative airway devices and cricothyrotomy success rates. Prehosp Emerg Care 2010; 14: 515-30

13. Heard C, Heard A, Dinsmore J. How difficult is it to identify anterior neck airway structures in the CICV scenario? Poster presented at 2012 American Society of Anesthesiologists' meeting, Washington DC, USA. www.asaabstracts.com/strands/asaabstracts/abstract.htm;jsessionid=2497AF213745589CA7F2F3860C5577B4?year=2012&index=15&absnum=3611 (Accessed 22 December 2015)

Conflict of Interest:

All the authors have taught, presented or published on CICO rescue techniques. Many CICO courses we have been involved in have received training equipment from Cook, VBM, and Meditech. A Heard has received funds from sales of his eBook, which have been used support CICO courses.

Submitted on 18/01/2016 7:00 PM GMT
After declaring a CICO?
18 January 2016
Benjamin Eagle

Dear Editor

I write to you with reference to the updated 2015 Difficult Intubation Guidelines (C.Frerk et al)published in the December 2015 edition of the Journal. I read with interest the updated guidelines and the changes that have been made over the 2004 guidelines.

The point of note that I wished to draw attention to relates to the description of the 'Plan C' Scenario. This describes the situation where SAD insertion has failed and attempts are now to be made at ventilation through the use of face mask and adjuncts. The text states that this may now have become more difficult if trauma to the airway has occurred during the previous intubation and SAD insertion attempts.

If these attempts are unsuccessful then the advice is that it should be declared that a CICO situation is in progress, and Plan D should be instigated. The Table 3 summary box in the paper then states that once CICO has been declared then one should continue to attempt to oxygenate via face mask, SAD and nasal cannulae, presumably whilst preparations are made for front of neck access.

Would DAS advocate in this instance returning to SAD insertion attempts whilst equipment is prepared or would it be felt more appropriate to simply persist with face mask ventilation that one would already be attempting at this point? Or perhaps would continued alternating attempts between SAD insertion and face mask ventilation be considered appropriate?

As we know this is likely to be a highly pressured situation - leading to considerable task fixation. Given that we have now declared that we are unable to intubate or oxygenate this patient are continued attempts at oxygenation of any benefit when perhaps at this point our full attention should be given to the preparation and consideration of our front of neck access equipment and patient positioning?

Kind Regards

Ben Eagle

Conflict of Interest:

None declared

Submitted on 18/01/2016 7:00 PM GMT
Team prepardness of the bloody airway
19 January 2016
Fozia Hayat

We welcome the DAS 2015 guidelines and feel that anaesthetists faced with the need to obtain front-of-neck access in an emergency will do so with greater confidence, speed and determination.

For onlookers, however, the unfolding scene may generate confusion, disbelief and horror- they may become paralysed with fear particularly if a long, deep and bloody wound is made - and the anaesthetist appears to tearing open the throat with his 'bare' hands.

Furthermore, faced with such a horrific scene the surgeon might mistakenly believe that the anaesthetist has taken leave of his senses and is in need of restraint rather than assistance! The context may be unclear.

Properly prepared, we feel that most surgeons, even if out of their familiar territory need not be out of their comfort zone. Therefore, we suggest that the WHO pre-list briefing should be used to warn the team of the possibility of Plan D manoevres when patients with anticipated difficult airways are listed. This would facilitate team preparedness in the event of both expected and unexpected emergencies.

We also feel that surgical trainees might perhaps value additional training in how best to manage the aftermath of such Plan D manoevres.

Conflict of Interest:

None declared

Submitted on 19/01/2016 7:00 PM GMT
A mark on the neck saves time