Cardiac Index Calculator
Calculate cardiac index from cardiac output and body surface area.
Understanding this tool
Why nurses use it
Cardiac index (CI) normalises cardiac output to body size (L/min/m²) — used in ICU haemodynamic monitoring alongside MAP, lactate, and perfusion assessment.
When to use it
Use when cardiac output and BSA are available from PAC, echo, or calibrated monitors.
Calculate
How to use this calculator
- Enter cardiac output (L/min) and BSA (m²).
- Interpret CI with clinical perfusion markers.
How the calculation works
CI = Cardiac output ÷ BSA. Typical resting range often quoted ~2.2–4.0 L/min/m² — interpret in context.
Formula used by this tool — verify units before applying at the bedside.
Worked example
Limitations & clinical notes
- Requires accurate cardiac output measurement method (PAC, echo, etc.).
- BSA should use same method as clinical team.
- Normal range varies with patient population and clinical context.
References
Key sources: Vincent JL — Cardiac index in critical illness.
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Disclaimer: This calculator is for educational and bedside double-check purposes only. It does not replace institutional protocols, prescriber orders, pharmacist verification, or clinical judgment. Always follow your local policies — especially for high-risk medications, infusions, pediatrics, and critical care. If the patient is acutely unwell, escalate immediately rather than relying on any calculator output.