Human factors in prehospital adverse events

defib

In the last decade or so, hospital medicine has learned (often the hard way) the importance of recognising the impact that human factors have when dealing with illness or emergencies.

While there is ample literature regarding the importance of human factors on the purely ‘aviation’ side of aeromedical work, there is little information about the importance (or otherwise) in the ‘medical’ side of prehospital care. The differences in environment, staffing, skill mix, time course of the patient, and a comparative paucity of resources means that extrapolating the ‘ED human factors‘ approach to the prehospital setting may not automatically be valid.

A study by the Ambulance Service of New South Wales, published in EMJ in 2012, sought to look at how human factors contributed to adverse events in the prehospital setting. The study involved surveying qualified and trainee paramedics regarding jobs they had been involved in where an adverse event or ‘near-miss’ occurred. Data was gathered for 370 jobs. On average, there were 10 contributing factors for each adverse event (range 5-15) – a typical ‘Swiss Cheese Model‘.

Factors which significantly increased the likelihood of an adverse event occurring were:

  • deteriorating patient (most important risk factor)
  • uncertainty about a change in patient condition
  • panic
  • on initial presentation patient seemed well
  • adaptation from low to high severity case
  • uncertainty in diagnosis
  • presence of reduced LOC
  • uncertainty in diagnosis

The presence of these factors, particularly grouped together, made adverse events or ‘near-misses’ more likely to occur.

(do these look familiar to anyone? I reckon most ED adverse events/near misses would have these factors as major contributors too!)

One of the most important points made in the discussion was

“The recognition of deteriorating and confounding patients, the management of uncertainty and decision making with impaired data may be considered as constructs of clinical judgement. If this conjecture is correct, then this study concurs with prior work that identified clinical judgement as the key issue in prehospital patient safety.”

The sequence of events that led to an adverse event or near miss was felt to be:

disconcerting patient factors –> uncertainty –> omissions –> patient harm

So how does this relate to our service?

  • factors contributing to adverse events or ‘near-misses’ in the prehospital setting are, according to this study, probably very similar to those that operate in our more familiar hospital setting. While we need to adapt to the prehospital environment, a new paradigm of thinking abut prehospital risk management to avoid error is probably NOT necessary.
  • assuming clinical judgement is a major issue in preventing prehospital adverse events, we should (in theory) be in a good position to counter this – our paramedic/doctor combination gives us clinical judgement from senior clinicians from two complementary backgrounds. Hopefully we have the best of both worlds.
  • Our model of care (doctor/paramedic/medically-trained crewman) puts us in a (relatively) well-resourced position to deal with deteriorating patients.
  • With ‘on initial presentation patient seemed well‘ being a risk for adverse events – we must keep in mind that complacency can be our enemy. With current dispatching protocols for our team, many of the jobs we do are based on geography rather than patient acuity, and many of the patients we transport are not actually that sick. Being lulled into a false sense of security and underestimating a patient’s illness/trajectory may be a significant risk for us.

Full text pdf for this post is available here (secure area limited to ADHB staff only – ADHB has online subscription access to this journal through the Philson Library at the University of Auckland School of Medicine)

Prehospital scene management

scene

As hospital doctors working in acute care, we have a considerable amount of control over the scene in which we work. Our ED resus bays have adequate space, lighting, and equipment (which is in the same place every time we need it). We have a huge number of team members we can draw upon for support in our patient care, and with prehospital notification of impending patient arrival we can assemble an appropriate team, set up relevant equipment ahead of time, and establish control over the scene before the patient arrives. We even have waiting areas for family and friends of critically ill patients and can delegate staff to look after them while a resuscitation is occurring.

In the prehospital setting, many of the factors above are unachievable, and to doctors this represents both a source of challenge and considerable discomfort.

One of the most interesting aspects of working as a doctor in the prehospital setting (both in practice and simulation) has been watching my paramedic colleagues in action at a prehospital scene – in particular the skill, calm, and aplomb with which they assess and manage a prehospital scene, and the adaptability with which this process occurs under highly variable circumstances.

While as HEMS doctors it would be uncommon for us to be in a position where we have a significant role in scene management – this role would usually be performed by ambulance staff already at the scene or by the helicopter paramedic – it is important for us to understand the process.

There is comparatively little literature available in this area. There are resources detailing ASSESSMENT of a scene, such as this chapter from the Prehospital Trauma Life Support manual.

With regards to MANAGEMENT of a prehospital scene, the authors of this study, published in EMJ in 2009, conducted interviews with experienced paramedics to generate a theory as to how paramedics manage a scene. The model that resulted was called “the space control theory of paramedic scene management”, which states that paramedics manage a scene by controlling the activities that occur in the space immediately around the patient “Space” is interpreted to include both physical and human (non-physical) elements.

“Although there are physical realities that present problems for scene management, for the most part the management of the scene involves how paramedics interact with other people. Indeed, it is through working with others that paramedics are able to solve the problems presented by both physical and human elements. This means that scene management is a dynamic social activity comprised of social processes.”

This figure from the paper provides overview of the theory:

space control theory

This model has multiple “human factors” elements – analogous to the increasingly recognised importance of human factors in hospital care.

Another useful resource for doctors at a prehospital scene is this 2007 slide set from Tony Smith – ADHB Intensivist, Medical Advisor to St John Ambulance, and Auckland HEMS doctor:

Slide1

Full-text pdf for this post is available here (secure area limited to ADHB staff only – ADHB has online subscription access to this journal through the Philson Library at the University of Auckland School of Medicine)