Fick Cardiac Output Calculator

Compute cardiac output by the Fick principle. Enter oxygen consumption, hemoglobin, and the arterial and mixed-venous saturations; add BSA for cardiac index.

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How it works

The Fick principle states cardiac output equals oxygen consumption divided by the arteriovenous oxygen difference: CO = VO₂ ÷ (1.36 × Hgb × 10 × (SaO₂ − SvO₂)), with saturations as fractions. Cardiac index is cardiac output divided by body surface area (normal 2.5–4.0 L/min/m²). Learn the theory in the hemodynamics study guide.

Frequently asked questions

How do you calculate cardiac output with the Fick method?

Divide oxygen consumption (VO₂) by the arteriovenous oxygen difference: CO = VO₂ ÷ (1.36 × hemoglobin × 10 × (SaO₂ − SvO₂)).

What is a normal cardiac output?

About 4–8 L/min; the cardiac index (output per m² of body surface area) is 2.5–4.0 L/min/m².

When is the Fick method most accurate?

In low-output states and when tricuspid regurgitation or an intracardiac shunt makes thermodilution unreliable.