Which of the following could indicate a malfunction of a pop-off valve on a BVM?

• A. Valve venting prematurely at low pressures
• B. Valve venting only when pressure reaches the threshold
• C. Valve produces a whistling sound during ventilation
• D. Valve not venting when pressure is high

Answer: (D)

The main idea is that the pop-off valve on a BVM acts as a safety release to prevent the circuit from building excessive pressure. It should stay closed during normal ventilation and open only when the airway pressure reaches the preset limit, letting air escape to avoid overdistention of the lungs.

If the valve does not vent when the pressure is high, it means the valve may be stuck closed or otherwise failed, so high pressures can build up. That defeats the safety purpose and can lead to barotrauma and inadequate ventilation, which is a clear malfunction.

Venting prematurely at low pressures would cause a loss of tidal volume and inefficient ventilation, not ideal behavior but often indicates the valve is not seating or calibrated correctly. Venting only when the threshold is reached is the intended functioning of the valve. A whistling sound could point to a leak or improper seating, signaling a possible issue, but it doesn’t directly demonstrate the valve failing to vent at high pressure.