Physiology Equations

Question 1

Cardiac Output (using the Fick principle)

Answer 1

Cardiac output = Oxygen Consumption / Ateriorvenous oxygen difference

CO = VO2/(CaO2-CvO2)

A commonly used value for VO2 at rest is 250ml/min

Question 2

Oxygen Content Equation

Answer 2

Oxygen Content = ([Hb]x1.34x[SaO2])+(0.02xPO2)

0.02xkPa or 0.003xmmHg

Normal values - Venous 15.2; Arterial 20.4mL/100ml

Question 3

Fick’s Law

Answer 3

Fick’s Law of Diffusion

Rate of Diffusion ~ (Surface Area x Concentration Difference)/Thickness of Membrane