Cardiac Output by Fick Principle (CO) | Online Free Tool | Elysia Tools
Elysia Tools
Navigation
Health
Cardiac Output by Fick Principle (CO)
Compute CO = VO₂ / (CaO₂ − CvO₂) / 10 (L/min) with the Fick principle. Requires PA-catheter mixed venous samples. VO₂ defaults to 250 mL/min. Derived from Fick 1870, StatPearls, LITFL, West, Leach 2002. Not medical advice.
Execution
Run this tool
Fill in the form, run the tool, and review the result in one place.
Samples
Examples that match this tool
Related
Continue with connected tools and hubs
Result
Ready for a run
Run the tool to preview files, text, structured data, or streamed output here.
Tool usage guide
Learn when to use this tool, what it supports, and how real users apply it.
Key facts
Category
Health
Input types
number
Output type
json
Sample coverage
4
API ready
Yes
Overview
The Cardiac Output by Fick Principle calculator estimates cardiac output in L/min from hemoglobin, arterial and mixed venous oxygen measurements, and oxygen consumption. It uses the Fick equation and requires mixed venous samples obtained through a pulmonary artery catheter. This tool is not medical advice.
When to use
Estimate cardiac output when arterial and pulmonary-artery mixed venous oxygen data are available.
Review the arterial–venous oxygen difference alongside the calculated Fick cardiac output.
Use a measured VO₂ value when available, or use the default estimate of 250 mL/min for a resting adult.
How it works
1Enter hemoglobin, SaO₂, PaO₂, SvO₂, and PvO₂ values using the specified units and fractional saturation format.
4It calculates cardiac output as CO = VO₂ ÷ (CaO₂ − CvO₂) ÷ 10 and rounds the result to the selected decimal places.
Use cases
A critical care clinician can estimate cardiac output from pulmonary artery catheter data and arterial blood gas measurements.
A cardiology trainee can check each component of the Fick calculation, including CaO₂, CvO₂, and the oxygen difference.
A hemodynamics review can compare a resting estimate with a calculation using directly measured oxygen consumption.
Examples
1. Normal resting cardiac output
Cardiology trainee
Background
A resting adult has hemoglobin of 15 g/dL, arterial saturation of 0.97, arterial PO₂ of 100 mmHg, mixed venous saturation of 0.75, and mixed venous PO₂ of 40 mmHg.
Problem
Calculate cardiac output and review the oxygen content difference.
How to use
Enter the five measurements and leave VO₂ at its default of 250 mL/min.
CaO₂ is 19.80 mL O₂/dL, CvO₂ is 15.20 mL O₂/dL, and the arterial–venous difference is 4.60 mL O₂/dL. Calculated cardiac output is approximately 5.43 L/min.
2. Low-output cardiogenic shock example
Critical care clinician
Background
A patient has hemoglobin of 12 g/dL, arterial saturation of 0.92, arterial PO₂ of 60 mmHg, mixed venous saturation of 0.50, and mixed venous PO₂ of 30 mmHg.
Problem
Estimate cardiac output using the available oxygen measurements.
How to use
Enter the arterial and mixed venous values, then use VO₂ of 250 mL/min or replace it with a measured value if available.
FAQ
What inputs are required?
Hemoglobin, SaO₂, PaO₂, SvO₂, and PvO₂ are required. VO₂ is optional.
What does the default VO₂ value mean?
VO₂ defaults to 250 mL/min, an estimate for a 70 kg adult at rest.
Can I enter a measured VO₂?
Yes. Enter the measured whole-body oxygen consumption in mL/min to replace the default estimate.
What type of venous sample is needed?
SvO₂ and PvO₂ should come from mixed venous blood obtained through a pulmonary artery catheter, not a peripheral venous sample.
What does the result include?
The JSON result includes cardiac output, arterial and venous oxygen content, the arterial–venous oxygen difference, and the VO₂ source.
CaO₂ is 14.97 mL O₂/dL, CvO₂ is 8.13 mL O₂/dL, and the arterial–venous difference is 6.84 mL O₂/dL. Calculated cardiac output is approximately 3.65 L/min, categorized by the example result as low.