What is the factor for 80/20 Heliox?

What is the factor for 80/20 Heliox?

• A. 1.8
• B. 1.6
• C. 1.4
• D. 2.0

Answer: (A)

Heliox changes how gas flows through the airways because helium is much less dense than air. Devices and flow meters in clinical use are calibrated for air, so when you switch to helium-oxygen mixtures, you can’t rely on the same flow settings to deliver the intended volume or flow. For an 80/20 heliox mix, a standard correction factor of 1.8 is used. This means you multiply the air-based flow setting by about 1.8 to achieve the same inspiratory flow and delivery of gas to the patient. For example, if you would deliver 10 L/min on an air-based setting, you would set about 18 L/min when using 80/20 heliox to achieve the same effect in the airway. The 1.8 factor accounts for the reduced density of the gas and its impact on flow through the airway and devices. (Different heliox mixtures have different correction factors, but 1.8 is the commonly used value for 80/20.)

Heliox changes how gas flows through the airways because helium is much less dense than air. Devices and flow meters in clinical use are calibrated for air, so when you switch to helium-oxygen mixtures, you can’t rely on the same flow settings to deliver the intended volume or flow. For an 80/20 heliox mix, a standard correction factor of 1.8 is used. This means you multiply the air-based flow setting by about 1.8 to achieve the same inspiratory flow and delivery of gas to the patient.

For example, if you would deliver 10 L/min on an air-based setting, you would set about 18 L/min when using 80/20 heliox to achieve the same effect in the airway. The 1.8 factor accounts for the reduced density of the gas and its impact on flow through the airway and devices. (Different heliox mixtures have different correction factors, but 1.8 is the commonly used value for 80/20.)