Which component meters the flow of gases such as oxygen and nitrous oxide to the breathing circuit?

Which component meters the flow of gases such as oxygen and nitrous oxide to the breathing circuit?

• A. Flowmeters
• B. Vaporizers
• C. Reservoir Bag
• D. O2 Flush Valve

Answer: (A)

Flowmeters regulate the rate at which each gas is delivered to the breathing circuit. In an anesthesia machine, each gas line has its own vertical flowmeter tube with a float that rises higher as flow increases; the float’s position corresponds to the flow rate in liters per minute. By adjusting the upstream control valves, you set how much oxygen or nitrous oxide reaches the common gas outlet, where the gases are mixed and then delivered to the patient. This precise metering is essential for controlling the inspired oxygen concentration and the overall gas mixture. Vaporizers are for turning liquid anesthetics into vapor and do not meter gas flow. The reservoir bag is used for manual ventilation and storage of gas, not measuring flow. The oxygen flush valve delivers a high-flow burst of oxygen directly into the breathing circuit, bypassing the flowmeters, so it does not perform the normal metering role.

Flowmeters regulate the rate at which each gas is delivered to the breathing circuit. In an anesthesia machine, each gas line has its own vertical flowmeter tube with a float that rises higher as flow increases; the float’s position corresponds to the flow rate in liters per minute. By adjusting the upstream control valves, you set how much oxygen or nitrous oxide reaches the common gas outlet, where the gases are mixed and then delivered to the patient. This precise metering is essential for controlling the inspired oxygen concentration and the overall gas mixture.

Vaporizers are for turning liquid anesthetics into vapor and do not meter gas flow. The reservoir bag is used for manual ventilation and storage of gas, not measuring flow. The oxygen flush valve delivers a high-flow burst of oxygen directly into the breathing circuit, bypassing the flowmeters, so it does not perform the normal metering role.