What is the factor for 70/30 Heliox?

What is the factor for 70/30 Heliox?

• A. 1.8
• B. 1.6
• C. 1.4
• D. 2.0

Answer: (B)

When delivering heliox, the gas density is much lower than air, so flowmeter readings (calibrated for air) don’t match the actual flow reaching the patient. To compensate, a flow correction factor is used. For a 70/30 helium–oxygen mix, the standard correction factor is 1.6. This means the true flow delivered to the patient is about 1.6 times the flow reading on a conventional flowmeter. For example, a 10 L/min indication would equate to roughly 16 L/min delivered. Different helium–oxygen ratios require different factors because the density difference changes with composition, so the correction varies accordingly.

When delivering heliox, the gas density is much lower than air, so flowmeter readings (calibrated for air) don’t match the actual flow reaching the patient. To compensate, a flow correction factor is used. For a 70/30 helium–oxygen mix, the standard correction factor is 1.6. This means the true flow delivered to the patient is about 1.6 times the flow reading on a conventional flowmeter. For example, a 10 L/min indication would equate to roughly 16 L/min delivered. Different helium–oxygen ratios require different factors because the density difference changes with composition, so the correction varies accordingly.