Stroke Volume Index Calculator

SVI Formula:

\[ SVI = \frac{SV}{BSA} \]

Stroke Volume Index (SVI):

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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 standardized measure of cardiac function that accounts for differences in body size.

2. How Does the Calculator Work?

The calculator uses the SVI formula:

\[ SVI = \frac{SV}{BSA} \]

Where:

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

Explanation: The formula normalizes stroke volume to body surface area, allowing for better comparison of cardiac function across individuals of different sizes.

3. Importance of SVI Calculation

Details: SVI is crucial for assessing cardiac performance, diagnosing heart failure, monitoring treatment response, and evaluating patients in critical care settings. It helps differentiate between various types of shock and guides fluid management.

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 like DuBois, Mosteller, or Haycock.

5. Frequently Asked Questions (FAQ)

Q1: What is the normal range for SVI?
A: Normal SVI ranges from 35-65 mL/m² in adults. Values below 35 mL/m² may indicate impaired cardiac function.

Q2: How is stroke volume measured?
A: Stroke volume can be measured using echocardiography, thermodilution, pulse contour analysis, or calculated as SV = CO / HR (cardiac output divided by heart rate).

Q3: Why normalize to body surface area?
A: Normalizing to BSA accounts for differences in body size, making cardiac parameters comparable across patients of different weights and heights.

Q4: What factors affect SVI?
A: SVI is influenced by preload, afterload, contractility, heart rate, and various pathological conditions affecting cardiac function.

Q5: When is SVI most clinically useful?
A: SVI is particularly valuable in critical care, heart failure management, perioperative monitoring, and assessing response to inotropic or vasoactive medications.