What patient characteristic influences the pressure limits used in PSV?

• A. Patient age only
• B. The size of the patient (infant, child, adult)
• C. Body temperature
• D. Underlying medical conditions

Answer: (B)

The characteristic that influences the pressure limits used in Pressure Support Ventilation (PSV) is the size of the patient, which includes considerations for infants, children, and adults.

In PSV, the ventilator assists the patient's breathing efforts by providing a preset level of pressure during inspiration. The appropriate pressure limits need to be adjusted based on the patient's size because anatomical and physiological differences affect respiratory mechanics. For instance, smaller patients may require lower pressure settings to avoid excessive pressures that can cause lung injury or discomfort, while larger patients may tolerate higher pressures due to their increased lung capacity and compliance. Hence, tailoring pressure limits to reflect the patient's size ensures optimal support while minimizing the risk of ventilator-induced lung injury and maintaining effective ventilation.

While age, body temperature, and underlying medical conditions can also affect ventilator settings in various ways, the direct influence on the pressure limits in PSV is primarily linked to body size, which plays a crucial role in determining lung compliance and overall respiratory mechanics.