When should the pop-off valve engage during manual ventilation with a bag-valve-mask?

• A. When pressure exceeds safe threshold during manual ventilation
• B. When patient is spontaneously breathing
• C. When oxygen tank is empty
• D. When bag is disconnected from mask

Answer: (A)

The pop-off valve on a bag-valve-mask is a safety release that prevents excessive airway pressure during manual ventilation. When you squeeze the bag, pressure builds, and if it reaches the valve’s preset limit, the valve opens to vent excess gas and keep peak airway pressures from becoming dangerous. This protection operates to prevent barotrauma, not to respond to whether the patient is breathing on their own. It’s also unrelated to whether the oxygen tank is full or empty or to the bag being disconnected from the mask—those situations affect ventilation quality, not the pressure-relief action. So it engages specifically to limit pressure when safe thresholds would be exceeded.