Preparing for, and more importantly preventing, ‘cannot intubate, cannot oxygenate’ events

Abstract

‘Cannot intubate, cannot oxygenate’ (CICO) situations occur when all efforts to oxygenate the patient using facemask, supraglottic airway device (SAD) and tracheal intubation have failed, the patient is consuming oxygen faster than it can be delivered and is at risk of imminent hypoxic brain injury, cardiac arrest and death. The quickest method of oxygenating a patient in this situation is to recognise the CICO emergency and perform an emergency front-of-neck airway (FONA) 1, usually in the form of a cricothyrotomy. ‘Cannot intubate, cannot oxygenate’ emergencies are rare and are associated with significant mortality and morbidity 1-3, especially if there is a delay in recognising the situation and/or performing cricothyrotomy 1, 3. In this issue of Anaesthesia 4, Rehak and Watterson obtained a 91% response rate in their survey investigating the institutional preparedness of anaesthesia teaching hospitals in Australia and New Zealand for CICO emergencies. This essentially establishes findings for an entire population of teaching hospitals, avoiding the need for inference statistics about a population from a smaller sample – a rare event in research. Establishing a protocol to manage CICO emergencies and removing barriers that prevent staff from performing a cricothyrotomy when one is needed, is every institution's responsibility. Although the Australian and New Zealand College of Anaesthetists (ANZCA) has highlighted CICO preparedness as one of its three teaching priorities, as Winston Churchill said ‘however beautiful the strategy, you should occasionally look at the results’ (https://www.wsj.com/articles/dont-quote-churchill-on-that-1514330569). Rehak and Watterson do this in detail, identifying and quantifying relevant issues in order to enable further improvements in CICO management 4. Rehak and Watterson investigated several equipment-related issues 4. These included the type of cricothyrotomy equipment available in each hospital, and whether point-of-care CICO equipment packs, used to perform a cricothyrotomy, were accessible and ready to use in each operating theatre or location where airway management occurs. The questionnaire also included human factors-related issues such as: the availability of cognitive aids; whether communication of a CICO emergency was clear and whether the language used to describe a CICO situation was simple and easy to understand; provision of staff training in CICO management and cricothyrotomy; and whether case-review systems were in place 4. Rehak and Watterson's survey highlights several points. Even though both countries follow the same difficult airway management guidelines 5, there were significant differences between cricothyrotomy equipment available in Australian hospitals compared with those in New Zealand. Australian hospitals were more likely to have point-of-care CICO equipment for both cannula and scalpel techniques rather than for scalpel techniques only (85% vs. 35%, p < 0.0001); in comparison, a greater proportion of New Zealand hospitals reported providing equipment for scalpel techniques only (59% vs. 4%, p < 0.0001). This disparity likely reflects the ongoing worldwide debate regarding cricothyrotomy technique 6, with an exception being the UK where a scalpel-only technique has been largely adopted 6, 7. Rehak and Watterson's survey suggests that there is also an inconsistent approach between teaching hospitals in Australia and New Zealand, with multiple equipment choices available to a clinician who has declared a CICO situation. Human factors and ergonomics can be defined as “making it easy to do the right thing” 8, 9: having more than one type of equipment available in a CICO emergency, when immediate action is required, appears to be the antithesis of human factors and ergonomics principles. This is a situation which an anaesthetist may face only once in their whole career 6. Simplifying the equipment available, and ideally standardising the technique, is likely to make it easier for staff to manage the situation well as a team 1, 4, 6, 7. A recent human factors and ergonomics study found that ‘providing enablers’ and ‘removing barriers’ were important aspects of system design, with equipment availability and location being the biggest enabler of good performance in difficult airway situations 10. Rehak and Watterson's survey found that 83% of operating theatres had a point-of-care CICO rescue kit, compared with 55% of satellite locations where airway management occurred. The American Society of Anesthesiologists’ 2019 publication, comparing airway closed-claims in the years 2000–2012 to those in the years 1993–1999, found an increase in medico-legal cases related to satellite locations 11. Point-of-care CICO packs are simple, inexpensive and avoid the need to fetch a difficult airway trolley or to gather equipment from various locations, thereby removing an ‘inaccessible equipment’ barrier 10, 12, reducing delays and diminishing potential psychological barriers to performing a cricothyrotomy 10, 11. Making the point-of-care CICO packs easily visible also provides an immediate prompt to perform a cricothyrotomy should one be needed 12. In a recent review of airway-related closed legal claims in the US, delay to initiating a cricothyrotomy in CICO situations was highlighted as a recurring issue leading to brain damage and death 11. We feel that hospitals around the world would do well to introduce point-of-care CICO packs in all areas where airway management occurs. We were pleased to see that 70% of hospitals in Rehak and Watterson's survey reported that one or more cognitive aids were routinely present in their operating theatres 4. Cognitive aids are prompts designed to help users complete a task or series of tasks 13, 14: they are likely to encourage transitioning from one stage of the failed intubation algorithm to another 13, 14 and may provide prompts to encourage staff to perform a cricothyrotomy in a timely fashion 9, 13, 14. In addition, they may help ‘flatten the hierarchy’ or ‘reduce the authority gradient’ within a team, encouraging more junior staff to speak up and suggest that a cricothyrotomy is necessary if they believe that one is required 1. Multiple cognitive aids are available for CICO emergencies, one example being the Vortex model 14, although of note most cognitive aids (including the Vortex model) have not been validated. Reporting and reviewing CICO emergencies, regardless of outcome, is essential for improving system design and team performance. Rehak and Watterson's survey revealed that reporting of CICO events took place in only 34% of responding hospitals, and review of cases involving difficult airway management occurred in only 56% 4. Use of the Airway App, a database accessed via a smart phone application and available to clinicians worldwide, provides an easily accessible method of recording such events and enables analysis of cases, looking for common themes and learning points 15. There are two important issues that we believe could have been addressed by Rehak and Watterson's survey. Their survey focuses solely on the endpoint of the failed intubation algorithm 7, that of cricothyrotomy during a CICO event, and concentrates on issues surrounding performance of the cricothyrotomy. Systems to prevent CICO emergencies from occurring were not investigated. If every patient underwent a thorough documented airway assessment 16 and creation of an airway management strategy 1, including awake tracheal intubation or tracheostomy when required and if there is enough time to do so 1, it is possible that a failed intubation or complication of airway management may be avoided altogether. Strategies to optimise laryngoscopy, including the use of videolaryngoscopes as first choice devices 17, proficiency and skill with videolaryngoscope hyperangulated blades 17, high flow nasal oxygen when difficult laryngoscopy is anticipated and optimising patient positioning before laryngoscopy 7, increase the chance of a successful first intubation attempt 17, 18. This is vital because, if the first attempt at tracheal intubation fails, the chance of successful intubation declines with each subsequent attempt at laryngoscopy 2, 17, 18, and the risk of hypoxia and hypotension increases. More than half of the incidents reported to the 4th National Audit Project in the UK (NAP4) involved problems with intubation as the incident progressed 1. Emphasis during airway training, regardless of clinical specialty or patient location, to ‘make the first attempt at tracheal intubation your best attempt’ is a strategy which is likely to reduce the chance of a failed intubation and its complications, potentially preventing a CICO situation. Likewise, using a second-generation SAD for all patients, when tracheal intubation and/or facemask ventilation has failed, may improve oxygenation more rapidly while decreasing the risk of aspiration of gastric contents compared with first-generation SADs 19. It would have been beneficial if Rehak and Watterson's survey had also investigated the availability of equipment for Plans A and B of the DAS 2015 guidelines for the management of unanticipated difficult intubation in adults 7. The second issue that could have been addressed in more detail is airway training 20. Although 89% of hospitals reported providing CICO rescue training, only 13% reported that this training was mandatory. Although CICO is one of three compulsory emergency response activities in the current ANZCA Continuing Professional Development program, which must be completed every 3 years 21, anaesthetists do not have to attend CICO training and can instead choose training in massive transfusion or anaphylaxis management. Is it now time for ANZCA to make CICO training mandatory for all anaesthetists every 3 years, and for other national bodies, such as the Royal College of Anaesthetists, to follow suit? Could this be taken even further, with national bodies mandating regular airway training for all anaesthetists of all grades, and indeed all who manage airways, covering airway rescue techniques as well as CICO training 6, 7, 20, 22? We believe that it is time to do so. Airway management is often learned as a solo development of skills and decision making. However, airway management is very much a team sport, especially during emergency situations. As airway managers, we have an obligation to train with our anaesthetic assistants, intensive care and emergency department colleagues in order to obtain and retain the necessary mutual skills to be effective team players. This may include mandatory out-of-theatre airway workshops 22, plus in-situ simulation training to provide staff with good technical skills, strategies to improve their non-technical skills 23 and reveal any potential deficits and system errors during such drills (https://chfg.org). Importantly, however well-trained a team is in both technical and non-technical skills, if that team is then placed back into a poorly designed work environment, it is highly likely that an error will occur. Consistent patient safety should not depend on the skills of individual clinicians but instead should be the result of incorporation of human factors and ergonomics expertise into the design of safe working systems in order to reduce the risk of an error occurring 9. In summary, Rehak and Watterson are to be commended for their assessment of CICO equipment preparedness in nearly all Australia and New Zealand anaesthesia teaching hospitals. Clinicians worldwide would be advised to examine the design of their working environment to ensure that the relevant equipment is immediately available, is simplified and standardised as much as possible, and that staff are familiar with its location and skilled in its use. As the next step, it would be advisable for hospitals to look at airway techniques and equipment used earlier in the failed tracheal intubation algorithm: assessing all patients with a thorough airway examination, creation of an individualised airway strategy, use of awake techniques when indicated, using advanced airway equipment as first choice devices, all coupled with appropriate training in these techniques and skills. Rehak and Watterson have shown that Australia and New Zealand are prepared for CICO emergencies in the operating theatre, but less so in out-of-theatre locations. No clinician should have to manage a CICO event because equipment was not available to prevent a difficult airway situation degenerating into a CICO emergency, or because they were insufficiently trained to use the available equipment. Prevention of a CICO emergency is perhaps the best means of managing one. FK's department has received equipment for evaluation, research and training at cost price, for free or on loan. LD is an editor of Anaesthesia. No other external funding or competing interests declared.

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