![Step 3: Do the math! CO = (VO 2 /[C A - C V ])*100 so: CO = (125/[200 - 150])*100](https://image.slidesharecdn.com/fickprinciple-110802140557-phpapp02/85/Fick-principle-7-320.jpg)
Fick principle
- 1. Fick Principle According to Jonathan
- 2. Cardiac Output The volume of blood being pumped by the heart in one minute. CO = SV x HR
- 3. Adolf Fick (1829-1901) Cardiac Output can be determined by the difference in concentration of a substance in the blood as it enters and exits an organ Allen Thicke
- 4. In order to apply the Fick Principle, the following must be known: Amount of marker substance taken up by the organ per unit time Concentration of marker substance in arterial blood supplying the organ Concentration of marker substance in venous blood leaving the organ Therefore: Cardiac Output can be determined from the difference in oxygen concentration in blood before it enters and after it leaves the lungs Blood flow to an organ can be calculated using a marker substance. organ = lungs marker substance = oxygen
- 5. Step 1: Determine Volume of O 2 consumed in one minute Using a spirometer with attached CO 2 absorber A commonly used value for O 2 consumption at rest is 125ml O 2 per minute VO 2 =125ml
- 6. Step 2: Determine O2 content in blood O 2 content in arterial blood Let’s assume oxygen concentration of arterial blood is approximately 200ml of O 2 per litre C A =200 ml O 2 / l blood O 2 content in venous blood Let’s assume oxygen concentration of mixed venous blood is approximately 150ml of O 2 per litre C V =150 ml O 2 / l blood
- 7. Step 3: Do the math! CO = (VO 2 /[C A - C V ])*100 so: CO = (125/[200 - 150])*100
- 8. When do we use the Fick Principle? We don’t. Sometimes used in renal physiology to determine blood flow in the kidneys Marker substance is not oxygen, but Aminohippuric acid
- 9. The End Class is not over. Do not leave yet. Cash donations accepted.