The Cardiac Index Calculator helps determine an individual’s cardiac output adjusted for body surface area (BSA). Cardiac index (CI) is a vital measure for assessing cardiac function relative to body size, providing a more personalized evaluation compared to cardiac output alone. By calculating CI, healthcare providers can better understand how well the heart is pumping blood to meet the body’s needs.
Formula of Cardiac Index Calculator
The formula for calculating the cardiac index (CI) is:
Cardiac Index (CI) = Cardiac Output (CO) / Body Surface Area (BSA)
where:
- Cardiac Index (CI) = Cardiac output adjusted for body surface area, measured in liters per minute per square meter (L/min/m²).
- Cardiac Output (CO) = The total volume of blood pumped by the heart per minute, measured in liters per minute (L/min).
- Body Surface Area (BSA) = The total surface area of the body, measured in square meters (m²).
Calculating Body Surface Area (BSA)
To calculate BSA, the Du Bois formula is commonly used:
BSA (m²) = 0.007184 × (Weight (kg) ^ 0.425) × (Height (cm) ^ 0.725)
where:
- Weight = Weight of the individual in kilograms (kg).
- Height = Height of the individual in centimeters (cm).
Final Calculation Steps
- Measure Cardiac Output (CO): This is typically obtained using medical devices.
- Calculate BSA: Use the Du Bois formula with the individual’s weight and height.
- Compute the Cardiac Index (CI): Divide the cardiac output by the calculated BSA to obtain the cardiac index.
Common Terms and Quick Reference Table
For ease of understanding and frequent usage, here is a table to assist users with general cardiac terms and values, enabling quicker reference without repeated calculations.
| Term | Definition | Units |
|---|---|---|
| Cardiac Output (CO) | Total blood volume pumped by the heart/minute | Liters/min (L/min) |
| Body Surface Area (BSA) | Total body surface calculated using height/weight | Square meters (m²) |
| Cardiac Index (CI) | Cardiac output normalized for body surface area | L/min/m² |
| Common CI Range | Normal values for healthy individuals | 2.5 to 4.0 L/min/m² |
These values are general reference points; actual values may vary based on the patient’s health, age, and body composition.
Example of Cardiac Index Calculator
To illustrate the calculation, let’s go through an example:
Patient Data:
- Weight: 70 kg
- Height: 175 cm
- Cardiac Output: 5 L/min
Step 1: Calculate BSA using the Du Bois formula:
BSA = 0.007184 × (70 ^ 0.425) × (175 ^ 0.725)
This gives a BSA of approximately 1.86 m².
Step 2: Calculate CI:
CI = Cardiac Output / BSA
CI = 5 / 1.86 ≈ 2.69 L/min/m²
This CI value of 2.69 L/min/m² falls within the typical healthy range, suggesting that the patient's cardiac output is likely meeting the body’s demands effectively.
Most Common FAQs
The normal range for cardiac index in healthy adults is 2.5 to 4.0 L/min/m². Values below or above this range may indicate cardiac issues, requiring further medical assessment.
The cardiac index provides a more accurate evaluation of heart function by considering body size, unlike cardiac output alone. This allows for a tailored assessment of whether the heart is pumping sufficient blood for the individual’s needs.
Cardiac output can be measured using medical devices, including echocardiograms, MRI, or catheterization. These devices monitor blood flow to estimate the volume pumped per minute by the heart.