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Cardiac Output Calculator
Cardiac output refers to the volume of blood pumped by each ventricle of the heart per unit time. Specifically, it is defined as the volume of blood pumped by the left or right ventricle every minute. The resting heart rate in an average individual is about 70 beats per minute (bpm). Stroke volume is the amount of blood pumped out of the left or right ventricle per heartbeat. Stroke volume is about 70 mL. Therefore, every contraction of the heart leads to about 70 mL of blood that is pumped out of the left ventricle and into the systemic circulation. Similarly, every contraction of the heart leads to about 70 mL of blood that is pumped out of the right ventricle and into the pulmonary circulation. Therefore, it can be seen that for an individual at rest, cardiac output is about 4,900 mL/min.
Considering the above information, it can be seen that in an average individual, nearly the entire volume of blood passes through the heart every minute! It is important to note that the cardiac output of the left heart must equal that of the right heart. This is important in order to prevent blood accumulation in one or the other circulation. Under pathological conditions in which the left ventricle is damaged (e.g., after myocardial infarction), the left heart is unable to keep pace with the right heart. This results in fluid backing up in the pulmonary circulation, which ultimately leads to fluid effusion into the pulmonary gas exchange sacs (alveoli). The accumulation of fluid in the alveoli hinders normal gas exchange in the lungs (O2 gain and CO2 elimination). This condition is referred to as pulmonary edema and, depending on its severity, it may be fatal.
The human heart is an amazing machine. As mentioned above, on average, the heart contracts 70 times per minute. Thus, the heart beats 4,200 times in one hour, 100,800 times in one day, 36,792,000 times in one year, and over a lifetime of 75 years, it beats 2,759,400,000 (2.7 billion times)! The heartís volume output (i.e., cardiac output) is also phenomenal. As noted above, on average, each ventricle pumps 4.9 liters of blood every minute. Thus, each ventricle pumps 294 liters of blood per hour, 7,056 liters per day, 2,575,440 liters per year, and over lifetime of 75 years, 193,158,000 liters of blood (51,026,945 gallons)! As there are two ventricles, and the output of the left and right ventricles must be equal under healthy conditions, the total volume output of the heart is twice the numbers given.
Cardiac output equation

Cardiac Output Equation

  • Cardiac Output (CO) refers to the volume of blood pumped by each ventricle of the heart per unit time. It is defined as the volume of blood pumped by the left or right ventricle every minute.
  • Heart Rate (HR) is the number of cardiac contractions per unit time. It is generally reported as beats per minute (or contractions per minute).
  • Stroke Volume (SV) is the volume of blood pumped out of the left or right ventricle per heartbeat. It is usually about 70 mL for each ventricular contraction.
Cardiac output calculator
Each calculator cell shown below corresponds to a term in the formula presented above. Enter appropriate values in all cells except the one you wish to calculate. Therefore, at least two cells must have values, and no more than one cell may be blank. The value of the blank cell will be calculated based on the other values entered. After a calculation is performed, the calculated cell will be highlighted and subsequent calculations will calculate the value of the highlighted cell (with no requirement to have a blank cell). However, a blank cell has priority over a highlighted cell.
Heart rate beats/minute
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Stroke volume mL/beat
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Cardiac output mL/minute
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Posted: Tuesday, April 23, 2024