Swiss Cheese & Systems Thinking

Swiss Cheese Modeling

Nothing happens in a vacuum. If you happen to be any of my instructors over my tenure in graduate school, chances are you’re sick of me starting papers with that, but it is one of the few constants I have found in my work in EMS, let alone the rest of my life. Everything has consequences, and you must continuously weigh the concept of cause and effect. It can be daunting, but over the years, I’ve found that a few baseline concepts help me create a framework that I approach every day life with-sometimes every hour, or sometimes just when I get a new partner or have a new project I need to figure out.

Swiss cheese. Ham and swiss. Maybe melted on roast beef. It does not matter; what does matter is if you take a slice of it and hold it up. It has holes in it. If that slice is cut all from the same larger piece of cheese, those holes line up easy, you can see right through them. If you move the cheese slices, even just a little, or use a different piece of cheese from a different cut, the holes don’t line up.

And besides getting awkward stares from whoever is watching you play with your cheese; you have just practiced some risk management. Often called the Swiss Cheese Model (SCM) is an immensely popular accident causation model; and reasonably well known in the safety industry (Underwood & Waterson, 2014).

(Smart, 2016)

At this point, you’re either asking what this has to do with pre-hospital care, or maybe you’ve drawn some conclusions, or you’re asking me to tell you something you don’t already know.

Well, here is the pitch: I think this model applies to almost everything we do in pre-hospital and interfacility critical care:  from interpersonal relationships with crew members to relationships with our patients and their safety. I think we can use the reverse swiss cheese model (which I just totally made up) to help us accomplish tasks and goals, instead of mitigating risk. I think if we use something called Systems Thinking, we can do it even better.

Where Does This Apply to EMS?

 I genuinely feel like this model can be used to help to provide a framework for a host of issues we face as pre-hospital providers:

  • I’ve recently been precepting new PRN EMTs at my agency, they come from a strong background via our reserve program, but lack call volume and exposure to patients. By sitting down and understanding the barriers to making their swiss cheese line up (to create change), we were able to build confidence and get them cleared as full providers. For one of the providers, I identified things that were keeping them overly comfortable-I had to take away the clipboard and insist they do the history and physical, and figuring out where to give her that little nudge lined her up for success.
  • You want to change your protocols/guidelines to be more up to date with evidence-based medicine but face issues with leadership and your medical director? What are those barriers, and how can you align everyone to create change?
  • Probably a well-known use of this in EMS is with RSI, checklists and other procedures help increase patient safety, address human factors, and reduce negative impacts. Making your checklist is helping those holes in the cheese not align (Sherren, Tricklebank, & Glover, 2014).
  • The reverse-model isn’t about avoiding adverse outcomes, but instead can be used to create positive change:blog2

Systems Thinking and Theory

What I think can help the Swiss Cheese Model shine is the concept of Systems Thinking. In the most basic way I can describe it, the idea is that everything you do happens in conjunction with the outside world and can have positive and negative effects on those people, agencies, and experiences (Comfort, Ko, & Zagorecki, 2004). Having a strong sense of where you fit in a system, both as an individual and as team providing pre-hospital care can be empowering when you understand the complexity of everything involved. I this most of us know the concept of cause and effect, but I’m not entirely sure we actively sit and think about it the wants and needs of those we interact with during our jobs as pre-hospital providers.

If you were to sit down and make a list of all the internal and external stakeholders that you interact with on just one, run-of-the-mill call, who would be on that list?

Off the top of my head, I have my internal wants and needs, my partner does as well, as well my agency does. Externally, stakeholders include the patient, other public safety/healthcare agencies, and probably your receiving facility. Obviously, sitting down making a list like this for every call you run is not practical, but what if you applied this to times when you are seeking change? I think a great example of this is re-writing or developing new protocols/guidelines.

When I was tasked with this, I looked at our current practice, and researched evidence-based information I found from open sources. I also looked to the regional medical center that takes most of our patients and had its own flight program… things have never been more smooth than when I start a patient on a drip based on the same guideline that the flight crew uses, and the ED or ICU that’s getting this infusion they are already familiar with. I embraced the system in which my patient care is part of, instead of just making decisions in a vacuum.

Some key points to think about Systems Thinking/Theory from an article called ‘Tools of Systems Thinker,’ includes some salient concepts (Acaroglu, 2018):

  • Interconnectedness: everything relies on something else to happen, function, or just exist. Think about this with problems you are trying to solve, identify the systems that make your problem an issue or that can help fix them. Heck, I think you should think about this to avoid problems as well.
  • Synthesis: Systems thinking is about bringing all the parts together, and understanding their complexity as a functioning system, in contrast to analysis which is breaking them all down.
  • Emergence: Emergence happens when you bring the nuance of the system together; all those separate stakeholder needs and input and start having a functioning system as a whole.
  • Feedback Loops: When there is input, there is output, and to have a functional system, you need to look at the feedback from the changes you made to create that system: are things balanced? Do you need more input from a stakeholder? Is a stakeholder unhappy or needing something to change?
  • Causality: Feedback loops help you understand relationships, this about really understanding the cause and effect that you see from feedback loops
  • Systems Mapping: This is precisely what you probably think it is… mapping out the system and how all the parts interact with each other.
(Acaroglu, 2018)

So, at this point, you are asking yourself two things:  how does the Swiss Cheese Model work with Systems thinking, and how can I apply this daily or in some combination of a functional manner?

Both of which are valid questions. Firstly, in my mind, these models go hand-in-hand. If I look at a problem I have at work, say wanting to change my guidelines, I first can mentally set up the (reverse) Swiss Cheese Model: what do I need to align in order make this happen? Conversely, I can apply the standard Swiss Cheese Model to help develop the procedure of the new guideline to mitigate issues that may cause my patient harm.

I can do my homework and find good research, recruit my fellow pre-hospital providers and get them on board, make sure we can afford any new drugs or equipment, and then win over my medical director with all that collaborative effort. This is recognizing the new guideline isn’t just a piece of paper.  As I’m doing that, I think about how the issue works as a system: can we support it financially, do we need this change of protocol, do we have the patient population to support the change? Does my system even need this guideline?

I get this can seem overly complicated, but I challenge you to go into your next project at work from a systems view point, and see how your external and internal shareholders interact with your day to day operations map it out, and throw some swiss cheese at your problems, you may just eliminate some risk or even improve some outcomes.

Acaroglu, L. (2018). Tools for Systems Thinkers : The 6 Fundamental Concepts of Systems Thinking. Retrieved May 23, 2020, from

Comfort, L. K., Ko, K., & Zagorecki, A. (2004). Coordination in rapidly evolving disaster response systems: The role of information. American Behavioral Scientist. ProQuest Central pg.

Sherren, P. B., Tricklebank, S., & Glover, G. (2014). Development of a standard operating procedure and checklist for rapid sequence induction in the critically ill. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, 22, 41.

Smart, B. (2016). Cloud Adoption: Risks & Mitigations Analysis | endjin blog. Retrieved May 22, 2020, from

Underwood, P., & Waterson, P. (2014). Systems thinking, the Swiss Cheese Model and accident analysis: A comparative systemic analysis of the Grayrigg train derailment using the ATSB, AcciMap and STAMP models. Accident Analysis and Prevention, 68, 75–94.



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