What is the relationship between Cardiac Output and Cardiac Index?

The relationship between Cardiac Output and Cardiac Index is established through the concept of body surface area. Cardiac Index is defined as the Cardiac Output adjusted for body surface area, allowing for a more precise comparison of cardiac function across individuals of different sizes. Specifically, Cardiac Index is calculated by dividing Cardiac Output (measured in liters per minute) by the individual's body surface area (measured in square meters). This adjustment makes it a valuable measure in clinical practice because it reflects how effectively the heart is pumping blood in relation to the body’s size, which is crucial for assessing cardiovascular health.

In contrast, stating that Cardiac Output equals Cardiac Index misunderstands the definitions and scales of these measurements. Claiming they are unrelated misrepresents their intrinsic connection, while suggesting that Cardiac Index is determined by multiplying Cardiac Output by body surface area misconstrues the formula, which requires division rather than multiplication. Understanding this relationship is important for clinical assessments and can aid in evaluating a patient's hemodynamic status.