What does cardiac output refer to?

Cardiac output is defined as the amount of blood the heart pumps in one minute, which is calculated by multiplying heart rate (the number of beats per minute) by stroke volume (the amount of blood ejected from the heart with each beat). This calculation provides a measure of the heart's efficiency and effectiveness in circulating blood throughout the body, which is crucial for delivering oxygen and nutrients to tissues and removing waste products.

Understanding this concept is key for assessing a patient's cardiovascular health and function. An increase or decrease in cardiac output can indicate various medical conditions and help guide treatment decisions. The focus on both heart rate and stroke volume highlights the dynamic nature of cardiac output, which can change in response to physical activity, illness, or other physiological changes.

The other options do not accurately define cardiac output; for instance, while the amount of blood ejected from the heart per beat is part of cardiac output, it does not take into account the heart rate, which is essential to understand the concept fully. Total blood volume in the body and the amount of oxygen transported by blood are related to cardiovascular and respiratory functions but do not specifically describe cardiac output.