Name: Governance of Cardiac Activity-be Heart Smart
Uploaded: 2019-07-19
Duration: 7 min 50 s
Description: Cardiac activity is regulated by nervous tissue, hormones, ions and the gender of the individual. It is time for a heart-to-heart about heart health.

Question

What is Fick's principle? How cardiac output is determined by this principle?

Accepted Answer

Adolf Fick, a German physicist established a method (Fick's principle) for the determination of cardiac output in human body. It is an indirect method for measuring the cardiac output by using the Douglas bag and gas analyzer instrument. According to the principle, if the total amount of gaseous exchange (0₂ or CO₂) per minute in lungs, the content of that gas (O₂ or CO₂) in both arterial and venous blood in that time are known, then the cardiac output can be easily determined by the following formula:
Cardiac output (ml/min) = Total amount of gaseous exchange (O, or CO₂) in lungs (ml/minute)/ Arterio-venous differences of the gas (O₂ or CO₂) (ml)/ml of blood x 100.
Let, the average amount of O₂ consumption per minute is 250 ml and the concentrations of O₂ in arterial and venous blood are 19 and 14 ml/ 100 ml, respectively.
Then, cardiac output (minute volume) – 250/5×100 = 5000ml.
and stroke volume= 5000 ml/72 beats = 70 ml (approx).

What is Fick's principle? How cardiac output is determined by this principle?

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