Which equation is used to calculate the cardiac index?

The cardiac index is a crucial parameter that allows for the assessment of the heart's performance relative to the body size, making it a more useful measure than cardiac output alone in certain patient populations. The formula for calculating cardiac index involves taking the cardiac output (C.O.), which is the volume of blood the heart pumps per minute, and dividing it by the body surface area (BSA). This results in a measurement that is expressed in liters per minute per square meter (L/min/m²).

The equation takes the stroke volume (the amount of blood pumped by the heart in one beat) and heart rate (the number of beats per minute), and the product of these two gives the cardiac output. Then, by factoring in the BSA, healthcare providers can account for varying body sizes, which is particularly important in pediatric or very large or small patients.

Calculating the cardiac index helps in assessing cardiac performance and comparing results across different individuals, making it a valuable tool in clinical settings for evaluating heart function.