In the Fick equation Q = VO2 / [(CaO2 − CvO2) × 10], what is the purpose of the factor 10?

In the Fick equation Q = VO2 / [(CaO2 − CvO2) × 10], what is the purpose of the factor 10?

• A. To convert from mL/dL to mL/L
• B. To convert to hours
• C. To adjust for body surface area
• D. To account for hydrogen ion concentration

Answer: (A)

The Fick equation links oxygen consumption to cardiac output and the difference in oxygen content between arterial and venous blood. VO2 is typically in mL per minute, while CaO2 and CvO2 are given in mL O2 per deciliter of blood. To keep units consistent and solve for cardiac output in liters per minute, you convert the oxygen content difference from per deciliter to per liter. Since there are 10 deciliters in a liter, you multiply by 10. This turns the denominator into mL O2 per liter, so VO2 (mL/min) divided by (ΔCaO2 × 10) yields Q in L/min. For example, if VO2 is 250 mL/min and ΔCaO2 is 5 mL/dL, the denominator becomes 5 × 10 = 50 mL/L, giving Q = 250 / 50 = 5 L/min. The factor 10 is simply the unit conversion from per deciliter to per liter; it isn’t about hours, body surface area, or hydrogen ion concentration.

The Fick equation links oxygen consumption to cardiac output and the difference in oxygen content between arterial and venous blood. VO2 is typically in mL per minute, while CaO2 and CvO2 are given in mL O2 per deciliter of blood. To keep units consistent and solve for cardiac output in liters per minute, you convert the oxygen content difference from per deciliter to per liter. Since there are 10 deciliters in a liter, you multiply by 10. This turns the denominator into mL O2 per liter, so VO2 (mL/min) divided by (ΔCaO2 × 10) yields Q in L/min. For example, if VO2 is 250 mL/min and ΔCaO2 is 5 mL/dL, the denominator becomes 5 × 10 = 50 mL/L, giving Q = 250 / 50 = 5 L/min. The factor 10 is simply the unit conversion from per deciliter to per liter; it isn’t about hours, body surface area, or hydrogen ion concentration.