What typically happens to tidal volume if a patient’s lung compliance worsens during PCV?

• A. Tidal volume increases
• B. Tidal volume remains constant
• C. Tidal volume decreases
• D. Tidal volume is eliminated

Answer: (C)

In the context of Pressure Control Ventilation (PCV), if a patient's lung compliance deteriorates, it results in a reduced ability of the lungs to expand. When compliance is lower, the lungs become stiffer, which means that for a given airway pressure, the volume of air that can be delivered to the lungs (tidal volume) decreases.

In PCV, the ventilator is set to maintain a specific pressure throughout the inspiratory phase. However, if compliance decreases, the lungs cannot achieve the same tidal volume since they are unable to stretch and accommodate the volume of air being delivered. As a result, the tidal volume delivered during each breath will decrease in response to the worsening lung compliance. This relationship is critical for understanding how the mechanics of ventilation work in patients with compromised lung function.