Unrecognised oesophageal intubation

Unrecognised oesophageal intubation has devastating consequences for all involved [1]. We summarise a case where unrecognised oesophageal intubation resulted in death from hypoxic brain injury [2], and consider how human factors and ergonomics (HFE) strategies might prevent harm from oesophageal intubation in the future.

Case summary

Glenda Logsdail, a fit and well 61 year old retired radiographer, was anaesthetised for an emergency laparoscopic appendicectomy in August 2020. Following pre-oxygenation and induction of anaesthesia, a theatre practitioner attempted intubation under the supervision of a consultant anaesthetist but was unsuccessful. The consultant then proceeded to intubate, but unfortunately placed the tracheal tube in the oesophagus and failed to recognise this. Three minutes later she became profoundly hypoxic; the anaesthetist misinterpreted the clinical picture as anaphylaxis and treated accordingly. A prolonged period of hypoxia culminated in cardiac arrest, a cardiac arrest call was made and a second consultant anaesthetist attended. Eleven minutes after the cardiac arrest call, the oesophageal intubation was recognised and the tracheal tube placed correctly. Return of spontaneous circulation occurred shortly after and she was transferred to ICU. Unfortunately, the unrecognised oesophageal intubation and subsequent prolonged hypoxia led to irreversible brain injury and she died five days later. Of note, she did not have a difficult airway, a standard Macintosh laryngoscope was used for all intubations, and continuous waveform capnography was in use throughout.

The Coroner issued a Regulation 28 ’Report to Prevent Future Deaths’ and the RCoA, DAS, SALG and Association of Anaesthetists are responding to this in detail. Glenda’s case involves technical skill issues including accidental oesophageal intubation and its delayed recognition, with minimal confirmatory checks of tracheal intubation evident. In addition, the Coroner commented on issues with non-technical skills: loss of situation awareness and erroneous fixation on the anaphylaxis diagnosis; team malfunction with “chaos and panic” in the anaesthetic room and confusion regarding roles; absence of a leader, with the lead anaesthetist “effectively blind to what needed to be done”; an “inhibitory team hierarchy” preventing other team members speaking out; and lack of standardisation of anaesthetic machine and ventilator monitors [2].

Human factors and ergonomics

HFE is a scientific discipline that ‘makes it easy to do the right thing and difficult, or ideally impossible, to do the wrong thing’ [3]. Its underlying principles are that, as humans, we are liable to make mistakes and that relying on personal performance – common in healthcare – is not a failsafe method of ensuring patient safety. HFE strategies can be described using the ‘hierarchy of controls’ model (Figure 1) [4], with strategies arranged as a pyramid in order of likely effectiveness.

Design

Design of safe systems, including equipment and working environment, is most likely to be effective and aims to prevent error occurring. Such design strategies are used in all UK safety-critical industries and account for ≈90% of safety improvements. Equipment design to prevent harm from oesophageal intubation includes videolaryngoscopy to increase first-pass intubation rate and reduce failed intubation, especially in patients with difficult airways [5]. Videolaryngoscopy offers communication benefits, with all team members able to see the view at laryngoscopy (‘changing intubation from me to we’), allowing the anaesthetic assistant to apply or adjust cricoid pressure, anticipate the next step and call for help if needed. These features flatten the team hierarchy and improve the recognition of oesophageal intubation. Videolaryngoscopy also improves intubation training [5].

Monitor design was highlighted by the Coroner after one anaesthetist mistook the airway pressure waveform for a capnography trace. SALG and industry colleagues are therefore discussing standardisation of the location and colour of the capnography trace on anaesthetic machine monitors and ventilators, and the use of ‘smart alarms’ that may improve detection of oesophageal intubation [6].

Design of the working environment during laryngoscopy can be optimised by positioning the videolaryngoscope screen on the opposite side of the bed to the anaesthetic assistant, enabling all team members to see the view at laryngoscopy, and improving recognition of oesophageal intubation. The Coroner commented on the cramped conditions in the anaesthetic room: induction of anaesthesia in the operating theatre provides more space for equipment and staff should an emergency occur.

Barriers

Barriers are HFE strategies that aim to ‘trap’ errors and prevent a patient coming to harm after oesophageal intubation. Examples include using capnography for all intubations, with the whole multidisciplinary team trained to recognise capnography waveforms and understand the significance of a flat trace [7]. In addition, a two-person verbal intubation check, with the intubator and anaesthetic assistant both visualising the tracheal tube passing through the vocal cords on the videolaryngoscope screen and confirming the presence of a capnograph trace on the monitor, has been proposed to improve the detection of oesophageal intubation.

Barriers also include the use of non-technical skills [8] during everyday work, including: use of team members’ first names; a verbal pre-induction team safety brief during preoxygenation confirming airway management plans; and specific tools including closed loop communication, standardised handover tools and graded assertiveness tools [8].

Mitigations

Mitigations are HFE strategies that reduce the consequences of an error, providing a final attempt to reduce harm from unrecognised oesophageal intubation. These include crisis management tools, non-technical skills and tools for regaining situation control in conditions of cognitive overload. Other mitigations include peer support tools that may reduce the impact of critical events on team members; these include Trauma Risk Management (TRiM), developed by the UK Armed Forces and recently introduced into healthcare [9].

Education, training, rehearsal and simulation

Education and training are essential for safety but will only be effective if other HFE strategies are in place; if a well-trained team is placed into an unsafe working environment then an error is likely to occur [4]. Education and training to prevent harm from unrecognised oesophageal intubation should include simulation training, including non-technical and crisis management skills, and out-of-theatre airway workshops covering airway rescue techniques. Optimising technical skills, including the technique required to use a hyperangulated videolaryngoscope blade, can ‘make room in one’s head’ for good non-technical skills. Training should be regular to prevent ‘skill decay’, multidisciplinary to flatten the team hierarchy, and arguably mandatory. Protected time should be allocated for staff to organise, run and attend training.

In summary, NAP4 included nine cases of oesophageal intubation, but 10 years after its publication patients are still dying following unrecognised oesophageal intubation. This might be prevented by: designing strategies to prevent oesophageal intubation occurring in the first place, potentially using videolaryngoscopes for all intubations; using methods to detect oesophageal intubation rapidly when it occurs by promoting capnography use and waveform recognition; protected time for multidisciplinary regular airway workshop and simulation training; and potentially making such training mandatory.

Figure 1. 'Hierarchy of controls' model

Paula Joy
Specialist Registrar 

Fiona E Kelly
Consultant
Department of Anaesthesia and Intensive Care Medicine
Royal United Hospitals Bath NHS Foundation Trust, Bath 

Twitter: @fionafionakel

References 

1. Cook TM, Harrop-Griffiths W. Capnography prevents avoidable deaths. British Medical Journal 2019; 364: 1439. 
2. Judiciary.UK. In the Milton Keynes Coroner’s Court. Inquest into the death of Glenda May Logsdail, Regulation 28: report to prevent future deaths, 2021. https://www.judiciary.uk/wp-content/uploads/2021/09/Glenda-Logsdail-Prevention-of-future-deaths-report-2021-0295_Published.pdf (accessed 25/11/2021). 
3. Kelly FE, Bhagrath R, McNarry AF. The ‘airway spider’: an education tool to assist teaching human factors and ergonomics in airway management. Anaesthesia 2018; 73: 257-8. 
4. Liberati EG, Peerally MF, Dixon-Woods M. Learning from high risk industries may not be straightforward: a qualitative study of the hierarchy of risk controls approach in healthcare. International Journal for Quality in Health Care 2018; 30: 39-43. 
5. Kelly FE, Cook TM. Seeing is believing: getting the best out of videolaryngoscopy. British Journal of Anaesthesia 2016; 117: i9-13. 
6. Pandit JJ, Young PJ, Davies M. Why does oesophageal intubation still go unrecognised? Lessons for prevention from the coroner's court. Anaesthesia 2021; in press. 
7. Royal College of Anaesthetists. Capnography: No trace = wrong place, 2021. https://rcoa.ac.uk/safety-standards-quality/guidance-resources/capnography-no-trace-wrong-place (accessed 25/11/2021). 
8. Flin R, Patey R, Glavin R, Maran N. Anaesthetists’ non-technical skills. British Journal of Anaesthesia 2010; 105: 38-44. 
9. Kelly FE, Osborn M, Stacey MS. Improving resilience in anaesthesia and intensive care medicine – learning lessons from the military. Anaesthesia 2020; 75: 720-3.