Question

What causes the pre-selected volume of air to flow into the patient by communicating directly with a breathing circuit?

• A. \( \text{Nebulizer} \)
• B. \( \text{Microcontroller} \)
• C. \( \text{Bellows} \)
• D. \( \text{Humidifier} \)

Hint:

In ventilators, the bellows} (or piston/turbine in modern designs) physically moves air, while the microcontroller} acts as the "brain" controlling the device’s functions. Knowing the distinct roles of components helps in troubleshooting and understanding ventilator operation.

Answer 1

The Correct Option is C

In mechanical ventilation systems, the component responsible for delivering the pre-selected volume of air to the patient by direct communication with the breathing circuit is the bellows. Bellows are flexible, collapsible chambers that expand and contract to draw in and then push out a precise volume of gas (air or a gas mixture) into the patient’s lungs. Other options explained:

• Nebulizer: Converts liquid medication into a fine mist for inhalation; it does not deliver bulk air volume.
• Microcontroller: An electronic controller that manages device operation but does not physically move air.
• Humidifier: Adds moisture to inspired gases but does not generate airflow.

Thus, the bellows is the direct mechanical device that moves the air volume into the patient’s breathing circuit.