Cardiac Output

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HunterMetcalfe.Cardiac Output
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The Cardiac Output calculator computes the output of a heart based on the heart rate, end diastolic volume and the end systolic volume.

INSTRUCTIONS: Choose units and enter the following:

• (HR) This is the heart rate
• (EDV) This is the End Diastolic Volume
• (ESV) This is the End Systolic Volume

Cardiac Output (CO): The calculator returns the output in liters per minute.  However this can be automatically converted to compatible units via the pull-down menu.

The Math / Science

Cardiac Output Is the volume of blood being pumped by the heart, in particular by a left or right ventricle in the time interval of one minute.

CO = HR • (EDV - ESV)

where:

• CO = Cardiac Output
• HR = Heart Rate in beats (strokes) per minute (BPM)
• EDV = End Diastolic Volume in volume unites, typically Liters (L)
• ESV = End Systolic Volume in volume unites, typically Liters (L)

The systolic and diastolic pressures references in this equation refer to maximum (systolic) and minimum (diastolic) pressures generated by the pumping heart.  Movement of blood through the circulatory system is a result of the pumping action of the heart.

The volume of blood flow is dependent on both blood fluid pressure and the resistance to flow presented by the blood vessels of the entire circulatory system.

Mean blood pressure decreases as the blood reaches smaller vessels further from the heart. Ultimately the blood pressure and resistance of the circulatory system translate as loss of energy. Mean blood pressure drops over the whole circulatory path.

Note that end diastolic Volume can never be zero. End systolic volume in theory could be 0 or negative, but this never happens clinically as some blood is left in the heart even with an ejection fracture of 100%.