The body’s cells require an adequate supply of oxygen (O₂) in the blood. This delivery (the oxygen flux) is dependent on the:

• Oxygen content of the blood
• Cardiac output

Oxygen content

When fully saturated 1 g of Hb holds 1.34 mL oxygen. Assuming a Hb concentration of 150 g/L (15 g/dL), we can calculate the oxygen content in arterial blood (CaO₂).

CaO₂ = Hb-bound + dissolved

= ([Hb] × 1.34 × satn) + (0.23 × PO₂)

= (150 × 1.34 × 0.98) + (0.23 × 13)

= 197 + 3

= 200 mL/L

Oxygen flux

Multiplying the CaO₂ by the cardiac output (5 L/min) gives the oxygen flux.

200 × 5 = 1000 mL/min