In the breathing system, which component is used for manual ventilation of the patient?

• A. Reservoir bag
• B. CO2 absorber
• C. Vaporizer
• D. Scavenging port

Answer: (A)

Manual ventilation relies on the reservoir bag, the flexible bag that sits in the breathing circuit. By squeezing this bag, you push a controlled amount of gas into the patient, delivering a breath with a known tidal volume. The bag acts as a gas reservoir, so ventilation can continue even if the ventilator is paused or temporarily unavailable. It also provides immediate feedback through visible chest rise and the feel of resistance, helping you judge adequacy of ventilation. The other components have different roles: the CO2 absorber removes exhaled carbon dioxide from the circuit, the vaporizer adds anesthetic agents to the inspired gas, and the scavenging port handles waste gas removal.