Which device is used to limit the maximum airway pressure in the breathing circuit?

Which device is used to limit the maximum airway pressure in the breathing circuit?

• A. Adjustable Pressure Limiting Valve
• B. Reservoir Bag
• C. Flowmeters
• D. Vaporizers

Answer: (A)

The device that sets and limits the maximum pressure in the breathing circuit is the adjustable pressure-limiting valve, often called the pop-off valve. It sits in the breathing circuit and can be opened or closed to control how easily gas can escape to the scavenging system. When you set a limit, once circuit pressure reaches that value, the valve vents excess gas, preventing further pressure rise and protecting the patient from barotrauma. This is the key function of the APL valve during manual and assisted ventilation. The reservoir bag mainly serves as a gas reservoir and a visual indicator of system status; it does not actively limit pressure. Flowmeters determine how fast gas enters the circuit but don’t cap the airway pressure. Vaporizers add anesthetic vapor to the gas mixture and have no role in restricting circuit pressure.

The device that sets and limits the maximum pressure in the breathing circuit is the adjustable pressure-limiting valve, often called the pop-off valve. It sits in the breathing circuit and can be opened or closed to control how easily gas can escape to the scavenging system. When you set a limit, once circuit pressure reaches that value, the valve vents excess gas, preventing further pressure rise and protecting the patient from barotrauma. This is the key function of the APL valve during manual and assisted ventilation.

The reservoir bag mainly serves as a gas reservoir and a visual indicator of system status; it does not actively limit pressure. Flowmeters determine how fast gas enters the circuit but don’t cap the airway pressure. Vaporizers add anesthetic vapor to the gas mixture and have no role in restricting circuit pressure.