Chapter 36 – Human Factors in Airway Management




Abstract




Human factors can be defined as the science of understanding of interactions among humans and other elements of a system, and how they can be adapted to improve performance and safety. Human factors issues were present in 40% of the cases of major complications in airway management in NAP4. Human factors issues can be considered in terms of ‘threats’ and ‘safeguards’. Threats increase the likelihood of the occurrence of an error that results in patient harm while safeguards help prevent this. Threats and safeguards in relation to human factors in airway management refer not only to ‘non-technical skills’ (e.g. situation awareness, teamwork) but also many other factors such as procedures, staffing and the physical environment in which airway management is conducted. Proper attention to human factors related issues contributes to both the prevention and effective management of airway emergencies and requires that these issues are considered as part of an integrated approach at the level of the individual, team, environment and organisation as part of routine airway care – not only when an emergency arises.





Chapter 36 Human Factors in Airway Management


Mikael Rewers and Nicholas Chrimes



What Is Meant by ‘Human Factors’?


Human factors (ergonomics) is the scientific discipline concerned with the understanding and optimising of interactions between humans and other elements of a system. It involves considering the individual, team, environmental and organisational factors that influence overall system performance (Table 36.1). It is as concerned with augmenting the human contribution to success as it is with protecting against the potential to contribute to error.




Table 36.1 Common human factors in airway management













































































































CATEGORY FACTORS THREATS SAFEGUARDS
Individual
Situation awareness (also at team level) Attention/vigilance, perception, problem detection, memory, recognition, comprehension, anticipation Distraction, lack of gathering all cues, distorted time perception, memory lapse, inadequate knowledge, inability to apply knowledge into context, poor communication, lack of ‘shared mental model’, assumption, fixation Continuous systematic scanning, cross-checking information, establishing/maintaining a ‘shared mental model’, declaring a situation, ‘thinking ahead’
Decision making (also at team level) Identify available options, judgement to select and implement, re-evaluation Poor situation awareness, poor judgement, failure to re-evaluate Cognitive aids, considering advantages/disadvantages, re-evaluating after each airway attempt
Personality Confidence, insight, willingness to act Overconfidence, denial, pride, guilt, diffidence Humility, willingness to ask for help, recognition of own limitations, reflection
Technical Competence, manual dexterity Inadequate skills, inadequate airway assessment Expertise, experience, supervision, training



  • Performance-shaping



  • factors

 Stimulation, mood, satiety, alertness, health, motivation, interest Stress, hunger, fatigue, illness/injury, apathy/improper motivation Calm, refreshed, sleep hygiene, alert, engaged
Team
Behavioural Coordination/leadership, role allocation, teamwork, communication Ineffective coordination/teamwork, role ambiguity, unclear communication, multiple ambiguous/conflicting terminologies Effective coordination/leadership, clear roles, cooperative teamwork, consultation, calling for help, team brief, names, closed loop communication, prompting, common goal, ‘speaking up’, ‘mini team time-out’
Social Interactions, familiarity Conflict, awkwardness, intimidation Harmonious relationship, understanding each other’s ideas or concerns
Work preparation Planning, preparing Limitation in strategies/plans, lack of available time to plan Strategy with contingency plans, checklists, taking only a few seconds to plan can be beneficial for decision- making and teamwork
Environmental
Equipment Design, availability, access, maintenance, function Inconsistent storage locations, clutter, poor user interface, design defects, equipment faults, inappropriate alarm settings or alert signals Suitability, proximity, visibility, readiness, well-designed equipment/alarms
Workspace Size, layout Crowding, obstructed views, poor equipment position Adequate space, optimal layout
Ambience Lighting, sound, temperature Inadequate lighting, noise ‘Sterile cockpit’, ‘Focus’
Organisational
Job factors Task complexity, staffing, workload Task difficulty, inadequate staffing, excessive workload, time/production pressure, night shift Assistance/backup
Policies/Procedures Guidelines, protocols, reporting, standards Lack of incident reporting or multi-professional morbidity/mortality meetings Learning through multi-professional morbidity/mortality meetings
Training/Supervision Programmes Lack of training, inadequate supervision Education, feedback, supervision, case discussion
Culture Management, norms, patient safety Judgemental culture, skewed norms, ‘waiting for errors to occur’ Non-judgemental culture, praise colleagues for good work, resilience

This chapter provides an overview of the principles of human factors in relation to airway management.



How Much Do Human Factors Impact on Airway Management Outcome?


Human error is implicated in up to 80% of anaesthetic incidents. The 4th National Audit Project (NAP4) in the United Kingdom concluded that human factor-related issues such as poor judgement, communication and teamwork contributed to 40% of major complications in airway management and were deemed to be major factors in 25% of these cases. In a follow-up study, Flin et al. identified an average of four contributing human factors per NAP4 case; the most frequent were failures to anticipate, wrong decision, task difficulty, inappropriate staffing, time pressure, tiredness, hunger, stress, poor communication and limitations in competence. The study also revealed protective factors such as good teamwork and effective communication. Overall, the contribution of human factors related issues to patient harm during airway management is at least as important as that resulting from technical issues.



Stop and think: is there any data on airway management outcomes in your department? What does the data show?



Why Do Human Factor-Related Adverse Events Occur in Airway Management?



Error Triggers


Human errors are inevitable, no matter how well trained and motivated an individual is.


‘Threats’ refer to aspects of the individual, team, work environment or organisation that can influence work performance by increasing the chance of an error (Tables 36.1 and 36.2). Threats will not inevitably lead to errors, nor will errors always result in adverse consequences. For the most part, additional contributing elements are necessary for an error to evolve into an adverse event. Small errors can trigger significant adverse outcomes and vice versa.




Table 36.2 Selected ‘threats’ from Table 36.1 with examples









































































































CATEGORY THREATS EXAMPLES OF RESULTING ERRORS IN AIRWAY MANAGEMENT
Individual
Situation awareness Distorted time perception


  • Distorted time perception leads to team failing to recognise how long patient has been hypoxic

Assumption


  • Assumption that lack of etCO2 trace or low SpO2 are errors

Fixation


  • Repeated attempts at intubation, prolonged hypoxia, airway trauma and potential precipitation of CICO

Personality Denial, pride, guilt •Refusal to acknowledge oxygenation is not occurring
•Trying to prove you can intubate the patient
•Clinician belief that they should have predicted or have precipitated the difficult airway
Technical Inadequate skills •Reluctance to perform front of neck airway rescue or awake flexible optical intubation
•High failure rate of front of neck airway rescue techniques
Inadequate airway assessment •Impaired situation awareness of airway risk
•Diminished ability to deal with airway challenges



  • Performance-shaping factors

 Stress, hunger, fatigue, illness/injury, apathy/improper motivation •May act as a distraction which impairs situation awareness
•May promote taking shortcuts e.g. inadequate airway assessment, planning, positioning or preoxygenation
Team
Behavioural Ineffective coordination/teamwork, role ambiguity, unclear communication •Duplication of tasks combined with failure to allocate other tasks: multiple people focused on getting emergency airway trolley, no one watching monitors
Multiple ambiguous/conflicting terminologies


  • E.g. surgical airway, eFONA, CICO rescue, infraglottic rescue; these terms may not be mutually understood by all team members leading to confusion and delays in execution

Social Conflict, awkwardness, intimidation


  • Failure to mention important information: e.g. ‘There’s no etCO2 trace’, ‘The patient is cyanotic’, or ‘The SpO2 has been <80% for 2 mins’

Environmental
Equipment Inconsistent storage locations, clutter


  • Difficulty locating airway rescue or CICO equipment

Poor user interface, design defects, equipment faults, inappropriate alarm settings or alert signals


  • Difficulty obtaining/interpreting information: misinterpreting airway pressure waveform or etO2 waveform as etCO2 trace



  • Alarms set too broadly fail to alert team to hypoxia (trigger too late)



  • If alarm settings are too sensitive clinicians develop ‘alarm fatigue’ and ignore them delaying recognition of a crisis



  • Inconsistent tone modulation with SpO2 change between different types of monitors



  • Tone modulation on SpO2 monitor switched off

Workspace Crowding, obstructed views, poor equipment position •Lack of visibility of monitors: failure to recognise falling SpO2, lack of etCO2 trace or other clinical abnormalities
Ambience Noise


  • Impaired communication, difficulty hearing SpO2 tone modulation or alarms

Organisational
Job factors Excessive workload, time/production pressure


  • Failure to develop an airway strategy, avoidance of awake flexible optical intubation, inadequate preoxygenation

Training/Supervision Lack of training, inadequate supervision •Inexperienced staff (airway operators & assistants) with poor decision making, inadequate airway skills
Culture Skewed norms


  • Acceptance of high risk behaviours, failure to assess airway, failure to plan

‘Waiting for errors to occur’


  • Only allows safety improvements to be implemented retrospectively (underestimation of risk)



CICO: cannot intubate, cannot oxygenate, FONA: front of neck airway




Table 36.3 Common human factor-related errors seen in airway crises






















ACTIONS RESULTS
Inadequate attempts at upper airway rescue: omission of optimisations or entire techniques Unnecessary front of neck airway rescue
Fixation on intubation: to the exclusion of upper airway techniques, airway trauma Precipitating CICO, delayed CICO rescue
Poor decision-making when oxygenation is present, ignoring options to wake or convert, repeated instrumentation Precipitating CICO
Fixation on upper airway techniques: failure to declare CICO and move to front of neck airway techniques Delayed CICO rescue


CICO: cannot intubate, cannot oxygenate



Stop and think: what threats can you identify in your clinical practice? How will you address these?



Stress


An airway crisis can be a high-stakes, time-critical situation. Excessive stress compromises the cognitive, communication and technical skills of clinicians, which may diminish their ability to resolve the crisis. Although the susceptibility of different individuals to performance impairment due to stress will vary, all clinicians will suffer from this phenomenon, if the pressure exceeds their limits.


Stress-related cognitive impairment may lead to fixation, distorted time perception, impaired knowledge recall and impaired judgement. These issues may combine to lead even experienced clinicians to make fundamental errors, considered inconceivable in the non-stressed state.


Failure to ‘do the basics’ under pressure is a recognised problem in real-life airway emergencies. No preceding attempt was made to place a supraglottic airway device (SGA) in over half of the cases of emergency front of neck airway in NAP4. Some common human factor-related errors seen in airway crises are listed in Table 36.3.

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Related posts:

Chapter 4 – Structured Planning of Airway Management Chapter 6 – Pre-anaesthetic Airway Endoscopy, Real and Virtual Chapter 13 – Supraglottic Airways Chapter 20 – Front of Neck Airway (FONA) Chapter 29 – The Patient with a Tracheostomy Chapter 26 – Ear, Nose and Throat Surgery: Airway Management
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Dec 29, 2020 | Posted by in EMERGENCY MEDICINE | Comments Off on Chapter 36 – Human Factors in Airway Management

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