A disadvantage of pressure ventilation includes:

The reason why inconsistent tidal volume due to variable lung compliance is identified as a disadvantage of pressure ventilation lies in the nature of how pressure ventilation operates. In this mode, the ventilator delivers a set pressure during inspiration, which allows air to flow into the lungs until that pressure is met. However, if the compliance of the lung changes—such as in cases of pulmonary disease, atelectasis, or other lung pathologies—the volume of air that enters the lungs can vary significantly.

For instance, if lung compliance decreases, the same pressure delivered may cause a smaller tidal volume because it is more difficult for the lungs to expand. Conversely, if compliance increases, a larger tidal volume may be delivered with the same pressure setting. This variability in tidal volume can lead to challenges in adequately ventilating the patient, especially in cases where consistent mechanical ventilation is crucial.

In contrast, stable tidal volume despite compliance changes, increased patient effort required for ventilation, and minimal risk of overdistention do not accurately represent the challenges associated with pressure ventilation. Understanding the implications of pressure ventilation on tidal volume is crucial for effective mechanical ventilation management.