1. What is Aortic Valve Stroke Volume Index?

Stroke Volume Index (SVI) is a hemodynamic parameter that represents the volume of blood pumped by the left ventricle per beat, indexed to body surface area. It provides a normalized measure of cardiac output that accounts for patient size.

2. How Does the Calculator Work?

The calculator uses the SVI formula:

Where:

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

Explanation: This calculation normalizes stroke volume to body size, allowing for better comparison between patients of different sizes and more accurate assessment of cardiac function.

3. Importance of SVI Calculation

Details: SVI is crucial for evaluating cardiac performance, diagnosing heart failure, monitoring treatment response, and assessing patients with valvular heart disease. It provides a more accurate reflection of cardiac function than absolute stroke volume alone.

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 the normal range for SVI?
A: Normal SVI typically ranges from 35-65 mL/m², though values may vary based on age, gender, and clinical context.

Q2: How is stroke volume measured?
A: Stroke volume can be measured using echocardiography, cardiac MRI, thermodilution, or pulse contour analysis.

Q3: Why index to body surface area?
A: Indexing to BSA accounts for differences in body size, allowing for more accurate comparisons between patients and establishing standardized normal values.

Q4: When is SVI particularly useful?
A: SVI is especially valuable in critical care settings, heart failure management, and preoperative cardiac assessment.

Q5: What does a low SVI indicate?
A: Low SVI may indicate impaired cardiac function, heart failure, hypovolemia, or other conditions affecting cardiac output.