Shock Hemodynamics

Each type of shock has a distinct hemodynamic fingerprint. Learn the profiles — and use the chart — to tell them apart at a glance.

What is shock?

Shock is a state of inadequate tissue perfusion — oxygen delivery fails to meet demand. Its four broad categories each disturb the pressure–flow–resistance balance differently, and hemodynamic monitoring (CVP, PCWP, cardiac output, and SVR) reveals which one you are dealing with.

The shock hemodynamics chart

This is the classic comparison — memorise the pattern, not just the rows:

*Depends on the cause (tamponade vs pulmonary embolism). **"Warm" distributive shock has high output early; it can fall late.

The four profiles explained

• Hypovolemic — lost volume → low filling pressures and low output; the body clamps down (high SVR).
• Cardiogenic — the pump fails → blood backs up (high PCWP/CVP) with low output and high SVR.
• Obstructive — a mechanical block (tamponade, massive PE, tension pneumothorax) impairs filling or ejection → high CVP, low output.
• Distributive — massive vasodilation (sepsis, anaphylaxis, neurogenic) → low SVR with high or normal output early.

Clinical pearls

Summary

• Shock = inadequate tissue perfusion, in four broad types.
• CVP, PCWP, cardiac output, and SVR together give the fingerprint.
• Distributive is the odd one out: low SVR.
• Use the chart to pattern-match quickly.

Frequently asked questions

What is the hemodynamic profile of each type of shock?

Hypovolemic: low CVP/PCWP, low output, high SVR. Cardiogenic: high PCWP/CVP, low output, high SVR. Obstructive: high CVP, low output, high SVR. Distributive: low SVR with high or normal output early.

What is a shock hemodynamics chart?

A table comparing CVP, PCWP, cardiac output, SVR, and SvO₂ across the four shock types so you can pattern-match the diagnosis.

How do you tell cardiogenic from hypovolemic shock?

Cardiogenic shock has high filling pressures (PCWP/CVP) with low output; hypovolemic shock has low filling pressures with low output.

Which shock has a low SVR?

Distributive shock (such as septic, anaphylactic, or neurogenic) causes vasodilation and a low systemic vascular resistance.