Hemodynamics

Cardiac Output (Fick Principle) Calculator

Cardiac output from oxygen consumption and the arterial-to-mixed-venous oxygen content difference (the Fick principle).

Reviewed by Alex G, BSN, RN, CEN, CCRN, CMC, NREMT-P · From the Reference tab of the app

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Formula

CO = VO₂ / ((CaO₂ - CvO₂) × 10)

Reference: Normal 4–8

How it is used

• Normal resting CO is 4–8 L/min.
• Used commonly with a Pulmonary Artery (Swan-Ganz) Catheter to determine accurate hemodynamics in complex shock.

Same formula as the app. Open it in the web app.

Related one-pagers

• Hemodynamic NormalsCardiac power output (CPO) · MAP × CO ÷ 451 · About 1 W at rest; under 0.6 W poor
• Shock Types at a GlanceCardiac power output, CPO = MAP × CO ÷ 451, is normally about 1 W; below about 0.6 W predicts death (Fincke 2004). PAPi = (PA systolic − PA diastolic) ÷ RAP flags RV failure below 0.9 in inferior MI (Korabathina 2012). SCAI stages are re-scored as the patient changes; in-hospital mortality rose from about 3% at stage A to about 67% at E in a cardiac ICU cohort (Jentzer 2019). Moving from C to D is the usual shock-team trigger for mechanical support.
• Obstetric EmergenciesCardiac output, L/min · 6.2 · 4.3 · Little reserve with stenotic valves or PAH
• Airway and RSICardiac output · Heart rate dependent; vagal · Bradycardia means hypoxemia until proven

Related calculators

• Cardiac Index (CI)
• Cerebral Perfusion Pressure (CPP)
• Mean Arterial Pressure (MAP)
• Oxygen Delivery (DO₂)
• Pulmonary Vascular Resistance (PVR)
• QTc (Bazett)
• Shock Index
• Stroke Volume (SV)

For education and exam preparation only. Follow your institution’s protocols. For education and exam preparation only. Verify results independently and follow your local protocols and medical direction. Not a substitute for clinical judgment.