The reservoir bag in the breathing system is primarily used for?

• A. Manual ventilation of the patient
• B. Scavenging anesthetic gases
• C. Measuring airway pressure
• D. Heating the gas

Answer: (A)

The reservoir bag is the expandable reserve you squeeze to deliver breaths when the patient is being manually ventilated. It stores a supply of fresh gas so you can generate inspiratory tidal volumes, observe chest rise, and provide rescue ventilation or assist during anesthesia when the ventilator isn’t delivering breaths. It also helps you feel the demand for ventilation and gauge how hard to squeeze.

Scavenging anesthetic gases, measuring airway pressure, and heating gas are handled by other parts of the system: scavenging is a separate port and system, airway pressure is read on the machine’s manometer, and gas heating isn’t a function of the bag.