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What The Duck! “The Convenient Abductive Reasoner”

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We’ve all heard that old adage: if it walks like a duck, swims like a duck, and quacks like a duck, it must be a duck. This is most definitely abductive reasoning. Abductive reasoning is defined as this: A chosen hypothesis that best fits the facts available. This is a logical process which best describes how we determine our field diagnoses of patients; and this is what guides our treatment based on what we see. 

I’m just going to throw this out there and say, that sometimes, even though all signs may point to a particular condition (“The duck”), we must be aware of the other types of conditions which may present in a similar fashion. Looks can be deceiving. There are a few common clinical presentations that stick out in my mind which are often encountered and thought or perceived to be benign. Let me go deeper and say this as well:

"What is actually driving our perception to make us believe something is more benign than it actually may be?"

We cannot forget the outside forces that may influence our abductive reasoning when it comes to those duck-like presentations. Certain opinions or subconscious factors can cause interference with how you view a situation and ultimately lead to bad reasoning. Say it is 6:30 PM and your shift is over at 7:00 PM. This patient in front of you who presents with syncope and who looks kind of sweaty, but not really, because It’s hot in here right? Right? 

You are trying to persuade yourself and others that “This is what caused the syncope and why the patient is diaphoretic.” This a type of confirmation bias - and it may bite us in the @ss when we are in the midst of assessing a patient.

Now here we are falling into the downward spiral of doing the least amount of work when it comes to this patient’s assessment and treatment (or lack thereof). Would that patient look sicker to you if it were 11:00 am as opposed to right before shift change? Would this factor make it easier for you to take a refusal or triage that patient to the local EMS squad? Should have done that 12-lead..just sayin’.

We tend to ignore certain facts or try to shape the situation based on outside factors or influences. These “factors” have to remain separate from our abductive reasoning. Attributing a bunch of signs and symptoms to a condition that we “want it (or hope for it) to be” vs “a strong possibility that it could be this” is a dangerous way of thinking. With that being said, let us review some of those “ducks” that we may be dealing with. 

The Anxiety Attack. 

Often times we are dispatched patient is complaining of shortness of breath or palpitations. When dispatch gives us some basic info, this is when the speculation begins. If it is a younger person, female, someone at work, more than likely your assumption is that this is an anxiety attack. So, the problem with this is that you’re already walking into the situation thinking this is not a life threat that and you will probably triage the patient back to the ambulance.

Your mind is made up before patient contact.

This is where that confirmation bias begins. So..this 30-something-year-old female patient is hyperventilating. She is sitting at her desk. She tells you that she feels anxious. Ok, fair enough. This confirms your original belief that this patient does not want to be at work and is having a full-blown anxiety attack. You get a basic set of vital signs and attempt to “coach” the patient to slow down her breathing. Your assessment is basic, and consists of two blood pressures, putting the patient on the monitor, pulse ox; and breath sounds. You obtain a medical history, but do this only by asking:

If the patient has a history of anxiety... she says yes.

If she takes any anxiolytic medications...she says no.

No allergies, right? No

Do you have chest pain? Nope.

Blood pressure is OK; Heart rate is at 118; But she is hyperventilating, so this is normal.

To you, this screams classic anxiety attack.

You send her on her merry way with the local EMS, only to find out later that she is has a PE.

Let’s review this.

A very basic ALS assessment; and leading questions - which end at the answers you seek. If you performed even a slightly more involved assessment and asked non-leading questions - your decision making could have easily changed.

ETCO2? How about a 12-lead ecg? Perhaps you would have noted the right ventricular strain pattern which was present.

How about what we asked the patient?

Leading questions; Not open-ended questions about medical history…total rookie move!

Perhaps you could have found out that the patient takes birth control and smokes. The latter could certainly guide you to perform more of a thorough assessment and higher index of suspicion. You had asked about chest pain specifically in your questioning. The patient may have told you her calf had been hurting for a few days. We cannot always assume that the patient is just going to give up all information. Look below the surface. You let your assumptions interfere with your perception. 

Syncope 

When we get dispatched to anywhere for “syncope,” I’m sure there are a significant number of EMS providers just praying that someone was having a bowel movement and pushed a little too hard. Even that comes with its own problems. But anyway, back to the point. There is a lot of crap (No pun intended) that can cause syncope. Again assessment, assessment, assessment. I mean can there be some weird stuff out there; absolutely…but don’t assume that you know the cause unless it is right in your face.

Ok, so picture this.

You get dispatched for someone who “passed out” while they were running a 5k. It’s a nice, hot day outside; and the patient is a relatively healthy looking 32-year-old male who was trudging along. The patient had briefly lost and then regained consciousness; and he says that he is slightly light-headed; but other than that, he feels ok. The path of least complexity pops up before you and you start with your very basic assessment.

So, let’s review: Not-young-but-not-old guy passes out. It’s hot and he is running. He needs some Gatorade.

Heart rate in the 50’s for the 2 minutes he is on the monitor, B/P is ok… and we got a blood glucose, which is normal. A hurried history is obtained; not super thorough. He did say that this has happened before when running, maybe once. He said he self-medicated with Gatorade; thinking he just needed some rehydration. This time though, something in your gut says, go with him to the hospital, ask some more questions, and monitor him. 

Enroute, to the hospital, you note that the patient begins having short runs of ventricular tachycardia. He says he continues to feel light headed. You perform a 12-lead ecg, and the patient shows a pattern consistent with left ventricular hypertrophy (LVH). You treat him accordingly and transport. Patient is later diagnosed with having hypertropic cardiac myopathy. You could have written this off as a big nothing, but you didn’t. Trust your gut as well. Assumptions and biases did not win here.

Chest Pain.

My least favorite. So, picture this. You are dispatched to a residence where there is a male patient in his 40’s who said he think he slept funny with his arms “scrunched up underneath him.” The patient reports pain in the center of his chest and that it radiates into his back. You push on his chest and he says “ouch.” Does is hurt more if I press or you take a deep breath? Yes, it does. The patient appears uncomfortable but not in any terrible amount of distress.  and states that the pain is 8/10. He reports that it is a sharp pain when you ask for a description. 12-lead looks ok; you look at ST-segments in AVL and V6 and note that they look a little elevated; not even a millimeter, but you write it off as a normal electrical variant for this patient.  After all, this guy has sharp chest pain that increases on inspiration and palpation, right? I bet he slept funny. Maybe pinched something, somewhere. No STEMI here guys..let’s go grab lunch, its noon.  

Wrong… dig a little deeper and don’t write it off. You go available and head to pick up your pizza and hear the ambulance requesting a paramedic intercept en route to the hospital for a now super-sick patient who’s ecg on arrival at the hospital looked like that of which nightmares are made of. Yikes! There was a decent article I read that referred to “minimizers” and the “myth-guided minimizer.” The refers to minimizing or underestimating symptoms. The “myth” that all sharp, right-sided, or reproducible chest pain is benign and cannot be of cardiac origin is unfortunately a belief among many providers. 

The whole point of this is to not let outside factors influence our decision making when it comes to how we assess and treat patients.  We have to be suspicious of what we find and not let biases interfere when looking at the ducks. This could cost us big time. Just remember that ducks may look calm as they move along the water. However, if you look below the surface you might see the frantic paddling. Everything is not always as it seems!

Ami Tomaszewski 

References:

Butte College; 2019. TIP Sheet: DEDUCTIVE, INDUCTIVE, AND ABDUCTIVE REASONING

http://www.butte.edu/departments/cas/tipsheets/thinking/reasoning.html

Thagard, Paul and Cameron Shelley. "Abductive reasoning: Logic, visual thinking, and coherence." Waterloo, Ontario: Philosophy Department, Univerisity of Waterloo, 1997. June 2, 2005. < http://cogsci.uwaterloo.ca/Articles/Pages/%7FAbductive.html>

Rollin J. Fairbanks, 2009. Don’t Be A Minimizer: Avoid the Trap of Underestimating Signs & Symptoms. JEMS. Issue 3 and Volume 34.

 

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