1. What is Stroke Volume Index?

Stroke Volume Index (SVI) is a hemodynamic parameter that represents the volume of blood pumped by the left ventricle per beat, normalized to body surface area. It provides a more accurate assessment of cardiac function than stroke volume alone, as it accounts for differences in body size.

2. How Does the Calculator Work?

The calculator uses the Stroke Volume Index formula:

Where:

• \( SV \) — Stroke Volume (mL)
• \( BSA \) — Body Surface Area (m²)

Explanation: This calculation normalizes stroke volume to body size, allowing for more accurate comparisons between individuals of different sizes.

3. Importance of SVI Calculation

Details: SVI is an important parameter in echocardiography and cardiac assessment. It helps evaluate cardiac performance, guide treatment decisions in heart failure, and assess response to therapy. Normal values typically range from 35-65 mL/m².

4. Using the Calculator

Tips: Enter stroke volume in milliliters (mL) and body surface area in square meters (m²). Both values must be positive numbers. BSA can be calculated using various formulas such as Du Bois or Mosteller.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal Stroke Volume Index range?
A: Normal SVI values typically range from 35-65 mL/m² in adults. Values below this range may indicate impaired cardiac function.

Q2: How is Stroke Volume measured in echocardiography?
A: Stroke volume is typically calculated as the difference between end-diastolic volume and end-systolic volume, often using Simpson's method or Doppler techniques.

Q3: Why normalize to body surface area?
A: Normalizing to BSA accounts for differences in body size, allowing for more accurate comparisons between individuals and establishing standardized reference ranges.

Q4: How does SVI differ from cardiac index?
A: Cardiac index is stroke volume index multiplied by heart rate (CI = SVI × HR). SVI measures volume per beat, while CI measures volume per minute, both normalized to BSA.

Q5: When is SVI particularly useful?
A: SVI is especially valuable in critical care settings, heart failure management, and when monitoring patients with significant weight changes or those at extremes of body size.