Pulse Pressure: The Vital Sign You're Probably Ignoring
Why Elite Critical Care Medics Never Look at Blood Pressure Alone
By Heroes Rise Coffee Company | EMS Education Series
Most providers see a blood pressure and immediately focus on one number:
"The systolic is 108... we're okay."
Or...
"The MAP is 65... good enough."
But what if I told you one of the most valuable pieces of information isn't the systolic, diastolic, or even the MAP?
It's the pulse pressure.
Learning to recognize abnormal pulse pressures can help you identify shock earlier, predict deterioration, and better understand what's happening inside your patient's cardiovascular system.
What Is Pulse Pressure?
Pulse pressure is simply the difference between the systolic and diastolic blood pressure.
Formula:
Pulse Pressure = Systolic BP − Diastolic BP
Examples:
120/80
Pulse Pressure = 40
140/90
Pulse Pressure = 50
88/76
Pulse Pressure = 12
That last one should immediately make you nervous.
What's Normal?
A normal pulse pressure is generally:
30–50 mmHg
Around 40 mmHg is considered healthy in most adults.
The farther you move away from that range, the more information your patient is giving you.
Why Does Pulse Pressure Matter?
Think about what creates a pulse.
Every heartbeat ejects blood into the arterial system.
The stronger the stroke volume...
The larger the pressure wave.
If stroke volume falls...
Pulse pressure narrows.
If stroke volume increases dramatically...
Pulse pressure widens.
Pulse pressure is often one of the earliest indicators that cardiac output is changing.
Sometimes long before the blood pressure crashes.
Narrow Pulse Pressure
Typically:
Less than 25–30 mmHg
Examples:
90/70
84/66
100/82
Notice something?
The systolic may not even look terrible.
But the pulse pressure is tiny.
That means the heart isn't generating much forward flow.
Common Causes
Hypovolemia
Trauma
GI bleed
Dehydration
Burns
Internal bleeding
Less preload equals less stroke volume.
Cardiogenic Shock
Large MI
Severe heart failure
Cardiomyopathy
Poor squeeze equals poor pulse pressure.
Cardiac Tamponade
One of the classic findings.
Blood fills the pericardium.
The heart cannot fill.
Stroke volume falls.
Pulse pressure narrows.
Massive Pulmonary Embolism
The right ventricle suddenly fails.
The left ventricle receives less preload.
Stroke volume plummets.
Tension Pneumothorax
Reduced venous return.
Reduced preload.
Reduced cardiac output.
Narrow pulse pressure.
Severe Sepsis (Late)
Early septic shock often has a wide pulse pressure.
Late septic shock develops myocardial dysfunction and hypovolemia.
Pulse pressure narrows.
Wide Pulse Pressure
Generally:
Greater than 60 mmHg
Examples:
160/70
150/60
170/65
This usually means either:
Very high stroke volume
OR
Very low vascular resistance.
Causes
Early Septic Shock
The classic "warm shock."
Massive vasodilation.
Diastolic pressure falls.
Pulse pressure widens.
The patient may actually look pink and warm.
Aortic Regurgitation
Blood leaks back into the ventricle.
Very high systolic.
Very low diastolic.
Massive pulse pressure.
Classic "water hammer" pulse.
Hyperthyroidism
High cardiac output.
Increased stroke volume.
Wide pulse pressure.
Pregnancy
Normal physiologic vasodilation.
Slightly wider pulse pressures are common.
Exercise
Large stroke volume.
Completely normal.
Increased Intracranial Pressure
As intracranial pressure rises, patients may develop:
Hypertension
Bradycardia
Irregular respirations
This is known as Cushing's Triad.
The systolic rises while the diastolic may not increase proportionally, creating a widened pulse pressure.
This is a critical sign of impending brain herniation and requires immediate recognition.
Why Trauma Medics Love Pulse Pressure
Imagine two patients.
Patient A:
118/80
Looks stable.
Pulse pressure = 38
Patient B:
108/94
Still "normal blood pressure."
Pulse pressure = 14
Which patient worries you?
Patient B.
Every time.
That narrowing pulse pressure may represent ongoing compensated hemorrhagic shock.
Blood pressure often remains "normal" until patients have already lost a significant amount of blood.
Pulse pressure frequently narrows much earlier.
Pulse Pressure in Septic Shock
One of the coolest trends to recognize.
Early sepsis:
130/55
Pulse pressure = 75
Warm extremities
Bounding pulses
Wide pulse pressure
As shock progresses:
90/72
Pulse pressure = 18
Cold
Poor perfusion
Organ failure
This trend often tells the story better than a single blood pressure reading.
Don't Ignore the Diastolic
Many providers glance only at systolic pressure.
The diastolic tells you about vascular tone.
Very low diastolic pressures often suggest vasodilation.
Very high diastolic pressures may indicate increased systemic vascular resistance.
Combining the systolic and diastolic gives you a much clearer picture of what's actually happening.
Pulse Pressure and Pressors
This is where critical care medicine becomes fascinating.
A narrowing pulse pressure may mean the patient needs:
Fluids
Blood
Inotropic support
Treatment of an obstructive cause
A wide pulse pressure with hypotension often points toward distributive shock, where vasopressors such as norepinephrine may be appropriate after adequate fluid resuscitation.
Always treat the patient—not just the monitor.
Trending Beats Single Measurements
Never rely on one blood pressure.
Watch the trend.
120/80
↓
110/78
↓
102/82
↓
94/84
The systolic doesn't seem catastrophic.
But the pulse pressure steadily shrinks:
40
32
20
10
That patient is telling you they're losing stroke volume.
Believe them.
Clinical Pearl
Every blood pressure should prompt three quick questions:
-
What is the MAP?
-
What is the pulse pressure?
-
Does this fit what I'm seeing clinically?
When those answers don't match, dig deeper.
The Bottom Line
Blood pressure is only part of the story.
Pulse pressure gives you insight into stroke volume, vascular tone, cardiac output, and shock state.
It can reveal compensated hemorrhage before hypotension develops.
It can distinguish warm septic shock from cold septic shock.
It can identify cardiogenic, obstructive, or distributive physiology in seconds.
Elite clinicians don't just memorize normal vital signs.
They understand the physiology behind them.
The next time your monitor cycles a blood pressure, don't stop at the systolic.
Take two seconds.
Subtract the numbers.
Your patient may already be telling you exactly what's wrong.
Quick Reference Cheat Sheet
| Pulse Pressure | Interpretation | Think About |
|---|---|---|
| <25 mmHg | Narrow | Hemorrhage, hypovolemia, cardiogenic shock, tamponade, tension pneumothorax, massive PE |
| 30–50 mmHg | Normal | Adequate stroke volume and vascular tone |
| >60 mmHg | Wide | Early sepsis, aortic regurgitation, hyperthyroidism, exercise, pregnancy, increased ICP |
Remember: Pulse pressure is one data point—not a diagnosis. Always interpret it alongside the patient's history, physical exam, perfusion, trends, and other vital signs.