Pressure Support Ventilation

Excerpt

Pressure support ventilation (PSV) is a mode of positive pressure mechanical ventilation in which the patient triggers every breath. PSV is deliverable with invasive (through an endotracheal tube) or non-invasive (via full face or nasal mask) mechanical ventilation. This ventilatory mode is the most comfortable for patients and is a useful ventilator setting for weaning from invasive ventilation and for providing supportive care with non-invasive ventilation. Flow (L/min) delivery is by setting a driving pressure (cmH2O). The flow delivered will be dependent on the set driving pressure, airway resistance, lung compliance, and inspiratory effort of the patient. The breath is flow-limited, meaning that the driving pressure terminates when the flow decreases to a set percentage (usually 25%) of the peak flow. Tidal volume (mL) delivered is dependent on the flow and the duration of the inspiratory phase. Settings for PSV mode include driving pressure, positive end-expiratory pressure (PEEP), and the fraction of inspired oxygen (FiO2). Minute ventilation (L/min) is dependent on the patient’s respiratory rate, and the tidal volume delivered with each breath. No mandatory breaths are given in PSV; thus, no minimum minute ventilation is ensured.