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