Which setting is used when the anesthesia machine is in bag mode with no fresh gas flow?

Which setting is used when the anesthesia machine is in bag mode with no fresh gas flow?

• A. Flowmeters to 0 L/min
• B. Flowmeters to 2 L/min
• C. Flowmeters to 5 L/min
• D. Flowmeters to 10 L/min

Answer: (A)

Bag mode is manual ventilation using the reservoir bag as the gas source. When there is no fresh gas flow, you set the flowmeters to zero so no external gas enters the circuit. This lets you squeeze the bag to deliver breaths while the circle system provides rebreathing and maintains the anesthetic concentration through the vaporizer and CO2 absorber. If the flowmeters were left at a positive setting, fresh gas would continuously flow into the circuit, defeating the bag-only ventilation and wasting anesthetic gas. So the correct setting is zero flow.

Bag mode is manual ventilation using the reservoir bag as the gas source. When there is no fresh gas flow, you set the flowmeters to zero so no external gas enters the circuit. This lets you squeeze the bag to deliver breaths while the circle system provides rebreathing and maintains the anesthetic concentration through the vaporizer and CO2 absorber. If the flowmeters were left at a positive setting, fresh gas would continuously flow into the circuit, defeating the bag-only ventilation and wasting anesthetic gas. So the correct setting is zero flow.