1. What is Cardiac Output Calculation?

Cardiac Output (CO) is the volume of blood the heart pumps per minute, measured in liters per minute (L/min). The VTI method uses echocardiography to estimate CO by measuring the velocity time integral, cross-sectional area, and heart rate.

2. How Does the Calculator Work?

The calculator uses the Cardiac Output formula:

Where:

• \( VTI \) — Velocity Time Integral (cm)
• \( CSA \) — Cross-Sectional Area (cm²)
• \( HR \) — Heart Rate (bpm)

Explanation: The equation calculates cardiac output by multiplying stroke volume (VTI × CSA) by heart rate, then dividing by 1000 to convert to liters.

3. Importance of Cardiac Output Measurement

Details: Cardiac output measurement is essential for assessing cardiac function, guiding treatment in heart failure, shock, and critical care settings, and evaluating response to therapy.

4. Using the Calculator

Tips: Enter VTI in cm, CSA in cm², and HR in bpm. All values must be valid positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal cardiac output range?
A: Normal cardiac output ranges from 4-8 L/min in adults at rest, but varies based on body size, age, and metabolic demands.

Q2: How is VTI measured in echocardiography?
A: VTI is measured using pulsed-wave Doppler at the left ventricular outflow tract (LVOT) or other cardiac valves to assess blood flow velocity over time.

Q3: What factors can affect cardiac output?
A: Heart rate, preload, afterload, contractility, and metabolic demands can all influence cardiac output measurements.

Q4: Are there limitations to this calculation method?
A: Accuracy depends on precise measurement of VTI and CSA. Assumes laminar flow and may be less accurate in patients with valvular disease or irregular heart rhythms.

Q5: When is cardiac output measurement most useful?
A: Particularly valuable in critical care, during cardiac surgery, and for monitoring patients with heart failure or shock.