Pressure support is a spontaneous mode of ventilation also named Pressure Support Ventilation (PSV). The patient initiates every breath and the mechanical ventilator delivers support with the preset pressure value. With support from the mechanical ventilator, the patient also regulates their own respiratory rate and their tidal volume.

In Pressure Support, the set inspiratory pressure support level is kept constant and there is a decelerating flow. The patient triggers all breaths. If there is a change in the mechanical properties of the lung/thorax and patient effort, the delivered tidal volume will be affected. The user must then regulate the pressure support level to obtain desired mechanical ventilation.

Pressure support improves oxygenation, mechanical ventilation and decreases work of breathing.