How much fresh gas-derived volume is delivered during inspiration if fresh gas flow is 6 L/min and the inspiratory time is 2 seconds?

How much fresh gas-derived volume is delivered during inspiration if fresh gas flow is 6 L/min and the inspiratory time is 2 seconds?

• A. 60 mL
• B. 120 mL
• C. 200 mL
• D. 300 mL

Answer: (C)

Fresh gas-derived volume depends on the flow rate and how long you breathe in. Multiply the fresh gas flow by the inspiratory time, making sure the units match. Convert 2 seconds to minutes: 2/60 = 0.0333 minutes. Then 6 L/min × 0.0333 min = 0.2 L, which is 200 mL. So, during a 2-second inspiration at 6 L/min, about 200 mL of fresh gas is delivered. (If you check the other numbers, 60 mL would need ~0.01 min, 120 mL ~0.02 min, and 300 mL ~0.05 min of inspiration.)

Fresh gas-derived volume depends on the flow rate and how long you breathe in. Multiply the fresh gas flow by the inspiratory time, making sure the units match.

Convert 2 seconds to minutes: 2/60 = 0.0333 minutes. Then 6 L/min × 0.0333 min = 0.2 L, which is 200 mL.

So, during a 2-second inspiration at 6 L/min, about 200 mL of fresh gas is delivered. (If you check the other numbers, 60 mL would need ~0.01 min, 120 mL ~0.02 min, and 300 mL ~0.05 min of inspiration.)