Which of the following is a hallmark of pressure-controlled ventilation?

• A. Fixed tidal volume delivery
• B. Volume delivery based on patient effort
• C. Limited airway pressure to prevent lung injury
• D. Rigid respiratory rates

Answer: (C)

The hallmark of pressure-controlled ventilation is the limitation of airway pressure to prevent lung injury. In this mode, the ventilator is set to deliver a breath with a specified maximum pressure. This allows the clinician to protect the lungs from excessive pressures, which can lead to barotrauma or volutrauma. By controlling the pressure, the ventilator adjusts the tidal volume delivered based on the patient's lung compliance and resistance, ensuring that the pressure does not exceed the set limit. This feature is particularly important for patients with compromised lung function, as it enhances safety while still facilitating adequate ventilation.

In contrast, fixed tidal volume delivery pertains to volume-controlled modes, where the specified volume is delivered regardless of airway pressure, which can risk lung injury if lung mechanics change. Volume delivery based on patient effort is more characteristic of assist/control or spontaneous modes, where patient-driven effort influences the volume delivered rather than a strictly controlled pressure. Rigid respiratory rates suggest a lack of adaptability in the ventilation strategy, which is not a feature of pressure-controlled ventilation, as it can allow variability in respiratory rates depending on patient needs and conditions.