In a rebreathing system, high-flow is defined as which range in ml/kg/min?

In a rebreathing system, high-flow is defined as which range in ml/kg/min?

• A. 10-20 ml/kg/min
• B. 40-100 ml/kg/min
• C. 200-300 ml/kg/min
• D. 0-5 ml/kg/min

Answer: (B)

High-flow in a rebreathing system means using enough fresh gas flow to effectively wash out exhaled gases and prevent significant rebreathing, allowing the inspired gas to be changed rapidly. In practice, this is about 40–100 ml/kg/min, which translates to roughly 2–7 L/min for an average patient. Flows well below that would not adequately purge CO2 and would slow changes in gas composition, while flows far above that are impractical for routine use. So the 40–100 ml/kg/min range best defines high-flow.

High-flow in a rebreathing system means using enough fresh gas flow to effectively wash out exhaled gases and prevent significant rebreathing, allowing the inspired gas to be changed rapidly. In practice, this is about 40–100 ml/kg/min, which translates to roughly 2–7 L/min for an average patient. Flows well below that would not adequately purge CO2 and would slow changes in gas composition, while flows far above that are impractical for routine use. So the 40–100 ml/kg/min range best defines high-flow.