What is the role of patient effort in PSV mode?

• A. It reduces tidal volume delivered
• B. It begins and controls the inspiratory phase of ventilation
• C. It keeps the ventilator from cycling
• D. It varies with different pressure levels set

Answer: (B)

In Pressure Support Ventilation (PSV) mode, the patient's effort plays a crucial role in initiating and controlling the inspiratory phase of ventilation. When the patient initiates a breath by creating negative pressure in the airway, the ventilator responds by delivering a pre-set level of pressure support throughout the inspiratory phase. This interaction allows the patient to have an active role in their breathing, as the ventilator assists with the effort the patient exerts to take a breath.

This mode is particularly beneficial for patients who may have respiratory muscle weakness or for those recovering from mechanical ventilation, as it encourages spontaneous breathing while providing support. The patient’s effort thus serves as a trigger for the ventilator, enabling them to control the rate and depth of their breaths to a certain extent based on their individual needs.

The other options do not accurately capture the primary function of patient effort in PSV. For instance, while tidal volume can vary with changes in effort, it is not solely reduced; the patient effort helps dictate how much assistive pressure is utilized during breathing. The ventilator doesn’t prevent cycling; instead, it cycles based on the detected effort. Lastly, the variation in pressure levels is more about settings rather than a direct correlation to patient effort.