In the listed composition of artificial air, which mixture is specified?

• A. 80% O2 + 20% He
• B. 80% He + 20% O2
• C. 100% O2
• D. 50% He + 50% O2

Answer: (B)

Heliox, a common artificial breathing gas, uses helium and oxygen in a fixed ratio to make breathing easier. Helium’s very low density lowers the gas density in the airways, which reduces turbulence and the work the lungs must do to move air, especially in obstructed or inflamed airways. The 80% helium and 20% oxygen mix delivers enough oxygen for patient needs while maximizing the density reduction that helps airflow. This is why the 80/20 helium–oxygen combination is the specified composition. The other options either swap the proportions or use pure oxygen, which doesn’t provide the same flow- ease or may pose safety concerns.