Airway management: Can't Intubate, Can't Oxygenate

SummaryWhile technical competence and adequate planning are crucial to effective airway management, it is well recognised that even well-prepared airway clinicians can sometimes fail to perform basic interventions under stress.

Abstract
Background: Appropriate planning is crucial to avoid morbidity and mortality when difficulty is anticipated with airway management. Many guidelines developed by national societies have focused on management of difficulty encountered in the unconscious patient; however, little guidance appears in the literature on how best to approach the patient with an anticipated difficult airway.

Methods: To review this and other subjects, the Canadian Airway Focus Group (CAFG) was re-formed. With representation from anesthesiology, emergency medicine, and critical care, CAFG members were assigned topics for review. As literature reviews were completed, results were presented and discussed during teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made, and levels of evidence were assigned.

Principal findings: Previously published predictors of difficult direct laryngoscopy are widely known. More recent studies report predictors of difficult face mask ventilation, video laryngoscopy, use of a supraglottic device, and cricothyrotomy. All are important facets of a complete airway evaluation and must be considered when difficulty is anticipated with airway management. Many studies now document the increasing patient morbidity that occurs with multiple attempts at tracheal intubation. Therefore, when difficulty is anticipated, tracheal intubation after induction of general anesthesia should be considered only when success with the chosen device(s) can be predicted in a maximum of three attempts. Concomitant predicted difficulty using oxygenation by face mask or supraglottic device ventilation as a fallback makes an awake approach advisable. Contextual issues, such as patient cooperation, availability of additional skilled help, and the clinician's experience, must also be considered in deciding the appropriate strategy.

Conclusions: With an appropriate airway evaluation and consideration of relevant contextual issues, a rational decision can be made on whether an awake approach to tracheal intubation will maximize patient safety or if airway management can safely proceed after induction of general anesthesia. With predicted difficulty, close attention should be paid to details of implementing the chosen approach. This should include having a plan in case of the failure of tracheal intubation or patient oxygenation.

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.

Abstract
Both the American Society of Anesthesiologists and the Difficult Airway Society of the United Kingdom have published guidelines for the management of unanticipated difficult intubation. Both algorithms end with the 'can't intubate, can't ventilate' scenario. This eventuality is rare within elective anaesthetic practice with an estimated incidence of 0.01-2 in 10,000 cases, making the maintenance of skills and knowledge difficult. Over the last four years, the Department of Anaesthetics at the Royal Perth Hospital have developed a didactic airway training programme to ensure staff are appropriately trained to manage difficult and emergency airways. This article discusses our training programme, the evaluation of emergency airway techniques and subsequent development of a 'can't intubate, can't ventilate' algorithm.

Abstract
Background: Previously active in the mid-1990s, the Canadian Airway Focus Group (CAFG) studied the unanticipated difficult airway and made recommendations on management in a 1998 publication. The CAFG has since reconvened to examine more recent scientific literature on airway management. The Focus Group's mandate for this article was to arrive at updated practice recommendations for management of the unconscious/induced patient in whom difficult or failed tracheal intubation is encountered.

Methods: Nineteen clinicians with backgrounds in anesthesia, emergency medicine, and intensive care joined this iteration of the CAFG. Each member was assigned topics and conducted reviews of Medline, EMBASE, and Cochrane databases. Results were presented and discussed during multiple teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made together with assigned levels of evidence modelled after previously published criteria.

Conclusions: The clinician must be aware of the potential for harm to the patient that can occur with multiple attempts at tracheal intubation. This likelihood can be minimized by moving early from an unsuccessful primary intubation technique to an alternative "Plan B" technique if oxygenation by face mask or ventilation using a supraglottic device is non-problematic. Irrespective of the technique(s) used, failure to achieve successful tracheal intubation in a maximum of three attempts defines failed tracheal intubation and signals the need to engage an exit strategy. Failure to oxygenate by face mask or supraglottic device ventilation occurring in conjunction with failed tracheal intubation defines a failed oxygenation, "cannot intubate, cannot oxygenate" situation. Cricothyrotomy must then be undertaken without delay, although if not already tried, an expedited and concurrent attempt can be made to place a supraglottic device.

Abstract
Background: Appropriate planning is crucial to avoid morbidity and mortality when difficulty is anticipated with airway management. Many guidelines developed by national societies have focused on management of difficulty encountered in the unconscious patient; however, little guidance appears in the literature on how best to approach the patient with an anticipated difficult airway.

Methods: To review this and other subjects, the Canadian Airway Focus Group (CAFG) was re-formed. With representation from anesthesiology, emergency medicine, and critical care, CAFG members were assigned topics for review. As literature reviews were completed, results were presented and discussed during teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made, and levels of evidence were assigned.

Principal findings: Previously published predictors of difficult direct laryngoscopy are widely known. More recent studies report predictors of difficult face mask ventilation, video laryngoscopy, use of a supraglottic device, and cricothyrotomy. All are important facets of a complete airway evaluation and must be considered when difficulty is anticipated with airway management. Many studies now document the increasing patient morbidity that occurs with multiple attempts at tracheal intubation. Therefore, when difficulty is anticipated, tracheal intubation after induction of general anesthesia should be considered only when success with the chosen device(s) can be predicted in a maximum of three attempts. Concomitant predicted difficulty using oxygenation by face mask or supraglottic device ventilation as a fallback makes an awake approach advisable. Contextual issues, such as patient cooperation, availability of additional skilled help, and the clinician's experience, must also be considered in deciding the appropriate strategy.

Conclusions: With an appropriate airway evaluation and consideration of relevant contextual issues, a rational decision can be made on whether an awake approach to tracheal intubation will maximize patient safety or if airway management can safely proceed after induction of general anesthesia. With predicted difficulty, close attention should be paid to details of implementing the chosen approach. This should include having a plan in case of the failure of tracheal intubation or patient oxygenation.

This report was written as part of the development process by the Australian and New Zealand College of Anaesthetists (ANZCA) for difficult airway management. The content of this review relates to the prevention, identification and management of decision to proceed to emergency surgical airway in the critical event of being unable to ventilate or oxygenate a patient having induced general anaesthesia. This is referred to as the “can’t intubate, can’t oxygenate” (CICO) scenario. This report forms the basis for ANZCA professional document PS61 and its accompanying background paper (PS61-BP).

Abstract
Background and objectives: Children undergoing airway management during general anesthesia may experience airway complications resulting in a rare but life-threatening situation known as "Can't Intubate, Can't Oxygenate". This situation requires immediate recognition, advanced airway management, and ultimately emergency front-of-neck access. The absence of standardized procedures, lack of readily available equipment, inadequate knowledge, and training often lead to failed emergency front-of-neck access, resulting in catastrophic outcomes. In this narrative review, we examined the latest evidence on emergency front-of-neck access in children.

Methods: A comprehensive literature was performed the use of emergency front-of-neck access (eFONA) in infants and children.

Results: Eighty-six papers were deemed relevant by abstract. Finally, eight studies regarding the eFONA technique and simulations in animal models were included. For all articles, their primary and secondary outcomes, their specific animal model, the experimental design, the target participants, and the equipment were reported.

Conclusion: Based on the available evidence, we propose a general approach to the eFONA technique and a guide for implementing local protocols and training. Additionally, we introduce the application of innovative tools such as 3D models, ultrasound, and artificial intelligence, which can improve the precision, safety, and training of this rare but critical procedure.

Abstract
At the Royal Perth Hospital, we have been developing and teaching a can't intubate, can't oxygenate (CICO) rescue algorithm for over 19 years, based on live animal simulation. The algorithm involves a 'cannula-first' approach, with jet oxygenation and progression to scalpel techniques if required in a stepwise fashion. There is little reported experience of this approach to the CICO scenario in humans. We present eight cases in which a cannula-first Royal Perth Hospital approach was successfully implemented during an airway crisis. We recommend that institutions teach and practice this approach; we believe it is effective, safe and minimally invasive when undertaken by clinicians who have been trained in it and have immediate access to the requisite equipment. The equipment is low cost, comprising a 14G Insyte cannula, saline, 5 ml syringe and a Rapid-O2. Training can be provided using low-fidelity manikins or part-task trainers.

The preferential use of a scalpel (SCT) or puncture techniques (PCT) for cricothyrotomy remains a controversial topic. This is a systematic review and meta-analysis comparing puncture cricothyrotomy with scalpel cricothyrotomy using overall success rate, first-time success rate, and time taken to perform the procedure as the primary outcome together with complications as a secondary outcome.

Airway obstruction requiring emergency airway rescue is an uncommon yet potentially fatal complication following anterior cervical discectomy and fusion. This report describes rapid clinical deterioration after anterior cervical discectomy and fusion despite haematoma evacuation.

Abstract
'Can't intubate, can't oxygenate' scenarios are rare but are often poorly managed, with potentially disastrous consequences. In our opinion, all doctors should be able to create a surgical airway if necessary. More practically, at least all anaesthetists should have this ability. There should be a change in culture to one that encourages and facilitates the performance of a life-saving emergency surgical airway when required. In this regard, an understanding of the human factors that influence the decision to perform an emergency surgical airway is as important as technical skill. Standardisation of difficult airway equipment in areas where anaesthesia is performed is a step toward ensuring that an emergency surgical airway will be performed appropriately Information on the incidence and clinical management of 'can't intubate, can't oxygenate' scenarios should be compiled through various sources, including national coronial inquest databases and anaesthetic critical incident reporting systems. A systematic approach to teaching and maintaining human factors in airway crisis management and emergency surgical airway skills to anaesthetic trainees and specialists should be developed: in our opinion participation should be mandatory. Importantly, the view that performing an emergency surgical airway is an admission of anaesthetist failure should be strongly countered.

Abstract
Guidelines outlining recommended actions are difficult to implement in the stressful, time-pressured situation of an airway emergency. Cognitive aids such as posters and algorithms improve performance during some anaesthetic emergencies; however, their effects on team behaviours have not been determined. In this study, 64 participants were randomly assigned into control (no cognitive aid) and intervention (cognitive aid provided) groups before a simulated 'can't intubate, can't oxygenate' scenario. Video analysis was undertaken of the non-technical skills and technical performance during the scenarios. All categories had higher Anaesthetists' Non-Technical Skills (ANTS) scores when a cognitive aid was supplied (mean (SD) total ANTS score 10.4 (3.1) vs. 13.2 (2.4), p < 0.001). The number of times the cognitive aid was used was associated with higher ANTS scores (ρ = 0.383, p = 0.002). A trend towards the establishment of an infraglottic airway within 3 min was also noted (control group 55.3% vs. intervention 76.9%, p = 0.076). Non-technical skills are improved when a cognitive aid is present during airway emergencies.

Abstract
Our objective was to survey all consultant surgeons, including obstetricians/gynaecologists, in the State of Western Australia to assess their experience with, and readiness to assist anaesthetists with a difficult or failed airway. Survey questionnaires were mailed to all surgeons registered in Western Australia (n = 445). A total of 238 responses (53%) were received, mostly from general surgeons, obstetrician/gynaecologists and orthopaedic surgeons. Forty percent had provided non-surgical assistance with a difficult airway and 60% had assisted with a surgical airway. All ear nose and throat surgeons who responded to the survey had assisted with an emergency surgical airway and 47 surgeons reported having performed six or more surgical airways. However 26% of respondents had never performed a surgical airway and 37% did not feel confident in performing an urgent surgical airway Seven percent of respondents reported witnessing a failed airway that resulted in death or neurological damage. Seventy percent of respondents had undergone formal training in tracheostomy and 26% had advanced trauma life support or early management of severe trauma training. These findings indicate that surgeons in Western Australia perform surgical airways infrequently and only occasionally assist anaesthetists with difficult airway management. However, some surgeons lack confidence and training in surgical airway management. Because anaesthetists cannot always rely on their surgical colleagues to provide a surgical airway during a crisis, we recommend that anaesthetists discuss airway management with their surgical colleagues for all patients with identified difficult airways and that anaesthesia training should include surgical airway management.