Human factors in prehospital adverse events


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)

Application of the Crewman’s Dictionary

In view of our upcoming ‘Equipment Usability Testing’ session, the following was circulated amongst the Auckland HEMS staff:
I) Here is one approach to the assessment of the ergonomics of a space:
  1. Attention and alertness
  2. Safety-critical information
  3. Position, placement and orientation of equipment
  4. Proximity of task, equipment and materials
II) Another approach (International Workplace Studies Program @ Cornell) emphasizes:
  1. Functional coherence
  2. Facilitation of communication
  3. Facilitation of task accomplishment
  4. Adaptable space

The Auckland HEMS doctors are fortunate to work closely with the helicopter crewmen. One of the many important functions the crewmen serve is to keep the doctors on Planet Earth. With this in mind, Herby Barnes (Crew Chief/Q.A. Manager) has consulted the crewman’s dictionary and provided the following real-world translation of the points above:

Approach I)

1.     If you didnt hear me the first time then go back to bed
2.     A thumb does not mean you look good in that jumpsuit
3.     Are you sure you’re in the right seat ?
4.     If you cant reach it MOVE !!!
Approach II
1.   Yes I am bigger and heavier and sometimes I may need to crawl all over you, so please do not get caught under me, we dont want another patient. 
2.   If you’re not kissing the MIC to talk, hand gestures are preferable to eyes or facial expression.
3.   Do your job or get off the machine.
4.   A space to secure extra crap that may be required, or recovered from the scene.
Given how slow HEMS doctors are at learning any practical helicopter-related matters, Herby has started their training at age 8

HEMS: Lessons from Helicopters to Fast Response Cars

This video shows a superb talk by Dr Gareth Davies, Clinical Director of the London HEMS. Topics covered include the role and structure of the service, the risks involved, and how those risks are mitigated with lessons learned from aviation.

This video comes from, a collaboration between various UK and USA hospitals and institutions which focuses on risk management and human factors in the medical setting.

Click here to watch the video.

Petro’s Prehospital Practice (session #2) A success!

Thursday’s have turned into our structured simulation day at the helicopter base. Part of my learning objective at ARHT (in Auckland) is to improve my abilities in running and debriefing simulation scenarios. While the group has (and continues) to run impromptu simulation sessions we have moved to a structured aspect that will allow us to be creative and try new things. We have the luxury of our Rescue Helicopter Trust being the subject of a TV show so there’s an abundance of footage of previous jobs. Today we selected a scenario from a previous episode that was viewed by the sim team before starting (check it out all the episodes here). This set the scene and we immediately jumped right into the scenario. The team stormed out to the scene and within minutes were immersed within the scenario. Check out a few pics from the scenario below.

Scott and Ati working hard during a V. Fib arrest. Great to see Scott providing some solid CPR!

The debrief – doing my best to keep people interested! Do you think they were listening?

The duty crew for the day formed today’s team and it was comprised of three members who did an awesome job! We had great teamwork from all three; Ati (crewman), Ross (Advanced paramedic), Scott (HEMS physician). Two key themes emerged from the day:

1) Role assignment and leadership: sometimes pre-assignment of a leader in the pre-hospital setting can be disrupted depending on available personnel (or lack thereof). The team decided as long as it’s well verbalized that there’s going to be a transition in leadership that it shouldn’t be an issue

2) Ergonomics: Placement of equipment and personnel is super important for being efficient and maximizing speed. Following the scenario we examined the set up the team had established then looked at ways to improve it. Chris Denny (HEMS physician supervising the scenario) spoke of using the stretcher as “table” and the use of angles as a strategy to improve scene ergonomics.

This session was a great opportunity for me to practice my debriefing skills using some stuff from the Harvard Simulation group. The idea of advocacy-inquiry method moves away from the idea that we shouldn’t judge during debriefings. Instead, the debriefer can provide an opinion but at the same time they try to understand how/why the learner decided to make such a decision even it may have been incorrect or controversial. “The instructor can help the learner reframe internal assumptions and feelings and take action to achieve better results in the future” (Rudolph JW et al. Simul Healthcare 2006).