Stroke Volume Index Calculator

Calculate the stroke volume index (SVI), which measures the volume of blood pumped by the heart per minute, normalized for body surface area. This helps assess cardiac function and is used in hemodynamic monitoring.

How to Use This Calculator

Enter the stroke volume in milliliters (mL)
Input the patient's height in centimeters
Enter the patient's weight in kilograms
Click Calculate to see the stroke volume index and interpretation

Formula Used

SVI = SV / BSA

Where:

SVI = Stroke Volume Index (mL/m²)
SV = Stroke Volume (mL)
BSA = Body Surface Area (m²) = √(height × weight / 3600)

Example Calculation

Real-World Scenario:

A 70kg male patient, 175cm tall, has a measured stroke volume of 80mL. Calculate the stroke volume index.

Given:

Stroke Volume = 80 mL
Height = 175 cm
Weight = 70 kg

Calculation:

BSA = √(175 × 70 / 3600) = √(12250 / 3600) = √3.403 = 1.84 m²

SVI = 80 / 1.84 = 43.5 mL/m²

Result: 43.5 mL/m² (Normal range: 33-47 mL/m²)

Why This Calculation Matters

Practical Applications

Assess cardiac function in critically ill patients
Monitor response to fluid therapy
Evaluate heart failure severity
Guide vasopressor therapy decisions

Key Benefits

Normalizes for body size variations
Provides standardized cardiac output assessment
Aids in hemodynamic monitoring
Helps identify low cardiac output states

Common Mistakes & Tips

Ensure height is in centimeters and weight in kilograms. Using inches/pounds will give incorrect BSA calculations. Always verify units before calculation.

SVI normalizes for body size, unlike raw stroke volume. A large person may have higher stroke volume but normal SVI, while a small person may have lower stroke volume but normal SVI.

Frequently Asked Questions

Normal SVI typically ranges from 33 to 47 mL/m². Values below 33 may indicate low cardiac output, while values above 47 may suggest high output states.

Stroke volume can be measured using echocardiography, thermodilution, or calculated from cardiac output and heart rate (SV = CO/HR).

SVI is particularly useful in critically ill patients, especially those with sepsis, heart failure, or shock, where assessing cardiac function is crucial for treatment decisions.

References & Disclaimer

Medical Disclaimer

This calculator is for educational purposes only and should not be used for clinical decision-making. Always consult with qualified healthcare professionals for medical advice and treatment. The calculations provided are approximations and may not account for individual patient variations.

References

2018 AHA/ACC/HFSA Guideline - Comprehensive heart failure guidelines
Body Surface Area Calculations - Evidence-based BSA formulas
Hemodynamic Monitoring in Critical Care - SVI clinical applications

Accuracy Notice

This calculator uses the Mosteller formula for body surface area calculation. Results are approximations and should be interpreted in clinical context. Input values should be verified for accuracy before use.

About the Author

Kumaravel Madhavan

Web developer and data researcher creating accurate, easy-to-use calculators across health, finance, education, and construction and more. Works with subject-matter experts to ensure formulas meet trusted standards like WHO, NIH, and ISO.

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health medical-clinical-calculators stroke volume index medical body weight

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