The following data were obtained from a man weighing 70 kg
• Aorta oxygen (O2) content = 20.0 vol%
• Femoral vein O2 content = 16 vol%
• Coronary sinus O2 content = 10 vol%
• Pulmonary artery O2 content = 15 vol%
• Total body O2 consumption = 400 ml/min 
what is the cardiac output of this man?
The Fick equation is a useful method for measuring cardiac output or flow through any organ when the oxygen (O2) consumption and the difference between arterial and venous O2 content (vol% = ml/100ml) is known.
Flow = O2 consumption /  arterial (O2 content – venous O2 content)
Cardiac output = O2 consumption / (aorta O2 – pulmonary artery O2)
= 400 / (20 – 15)
= 8 L/min
10 L/min
5 L/min
5 L/min
8 L/min