Why Pathophysiology and Critical Thinking Are Intertwined in EMS

Understanding pathophysiology is what transforms critical thinking in EMS from guesswork into informed, patient-centered decision-making.

I was on a call recently that reminded me how deeply pathophysiology applies to everyday EMS practice. Details have been altered to protect patient privacy.

EMS Case Study: Patient Assessment

A woman in her 70s had fallen and had been on the ground for approximately two hours. She reported significant pain on palpation of her left hip and proximal femur. There were no other complaints, and the remainder of the physical exam was unremarkable.

Vital signs were BP 118/86, pulse 106 (strong and regular), respirations 14, and SpO₂ 98% on room air.

The patient is prescribed atenolol and atorvastatin but has not taken them for several days. She reports having “heart issues” but cannot provide further detail. She denies syncope and any cardiac or respiratory symptoms prior to the fall. She is lying in water that may have contributed to the fall and is soaked from the waist down. Ambient temperature is approximately 72°F.

How Pathophysiology Improves Patient Assessment in EMS

This case highlights an important intersection between shock, hypothermia, and medication effects. Pathophysiology helps us understand the underlying mechanisms guiding clinical decisions. It shapes the questions we ask and the details we prioritize.

Here is how that thought process unfolds:

Atenolol is a beta blocker.

I know this because of pathophysiology and the -olol suffix. It can slow the heart rate and lower cardiac output. The patient hadn’t taken it recently and this may result in an elevated heart rate.

Is the patient in shock?

• Is the tachycardia due to shock, pain, hypothermia, or medications?

• If the atenolol is used for rate control, this may explain the tachycardia. The heart rate seemed regular on initial palpation, but a-fib without rate control meds could also cause this.

• If atenolol was used for hypertension (which isn’t the most common med choice for this), could 118/86 be relative hypotension or a bigger downward trend than it appears?

• Could there be a hypotension exacerbation issue when administering analgesic medications?

How can I differentiate between these issues?

• Monitoring the pulse for irregularity or performing an ECG (paramedic level) will help me identify a-fib and rate issues.

• Trying to get additional history on the patient

• The pulse pressure is within the normal range, but not by much. Pulse pressure should be at least 25% of the systolic BP (at least 29 - 30) and is 32. MAP is 96.

• Trending:

  • Ongoing pulse monitoring, especially for irregular pulses

  • Ongoing BP monitoring and appropriate BP measurement techniques for accuracy

  • Eliminating causes of tachycardia (remove wet clothes and warm the patient, calm and reassure, analgesia if in scope and supported by vital signs)

  Preemptive consideration of shock

  • Transport decision for orthopedics and surgery (trauma) capability

  • Maintain body temperature

  • IV access and monitor hemodynamics

Now let’s compare this to an EMT or ALS provider who doesn’t look into causes with an eye toward pathophysiology. It’s dangerously simplistic:

"Pulse is a little elevated, but the BP is good. We’ll transport."


Could that approach occasionally lead to a good outcome? Possibly. But it relies on chance rather than clinical reasoning.

Case Study Wrap-Up: What Happened After Assessment?

On this call, the integrated assessment supported establishing IV access and administering analgesia prior to movement, both clinically appropriate and humane given the patient’s pain. An ECG obtained during transport showed sinus tachycardia rather than atrial fibrillation. The heart rate decreased slightly after analgesia but remained mildly elevated. Blood pressure and pulse pressure remained stable.

The patient was transported to a trauma center and transferred to receiving staff. And, for a pathophysiology-minded provider, it was a good day.