Which formula is used to calculate Cardiac Index?

The Cardiac Index is a crucial measure in cardiology, as it relates cardiac output to body surface area (BSA), allowing for a more individualized assessment of heart performance. The formula for calculating Cardiac Index is CI = Qt / BSA, where Qt represents cardiac output (the amount of blood the heart pumps in a minute), and BSA is the body surface area measured in square meters.

This formula effectively standardizes cardiac output, as it takes into account the size of the individual, thus making it more meaningful across different body sizes. A higher Cardiac Index indicates better cardiac performance relative to the individual's body size, while a lower value could suggest inadequate heart function or decreased output for the person's size.

Since the choices involving addition and multiplication do not properly reflect the relationship between cardiac output and body surface area necessary to calculate the Cardiac Index, it clarifies that the use of division in the correct answer aligns with the physiological concept of normalizing cardiac output.