How do you calculate cardiac output?

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Multiple Choice

How do you calculate cardiac output?

Cardiac output is the volume of blood the heart pumps each minute, and it’s determined by how much blood is ejected with each beat (stroke volume) and how many beats occur each minute (heart rate). Multiply stroke volume by heart rate to get cardiac output, which is the flow of blood per minute. For example, about 70 mL per beat at 70 beats per minute gives roughly 4.9 L per minute. The other ideas mix quantities that don’t directly translate to flow. Heart rate with systolic pressure pairs a rate with a pressure, not a volume, so the units don’t match a flow. Cardiac index times vascular resistance isn’t the standard way to compute CO and doesn’t yield the volume per minute. Preload times afterload relates more to myocardial work than to the actual rate of blood pumped per minute.

Cardiac output is the volume of blood the heart pumps each minute, and it’s determined by how much blood is ejected with each beat (stroke volume) and how many beats occur each minute (heart rate). Multiply stroke volume by heart rate to get cardiac output, which is the flow of blood per minute. For example, about 70 mL per beat at 70 beats per minute gives roughly 4.9 L per minute.

The other ideas mix quantities that don’t directly translate to flow. Heart rate with systolic pressure pairs a rate with a pressure, not a volume, so the units don’t match a flow. Cardiac index times vascular resistance isn’t the standard way to compute CO and doesn’t yield the volume per minute. Preload times afterload relates more to myocardial work than to the actual rate of blood pumped per minute.

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