Pressure support ventilation

Pressure support ventilation (PSV) is one of the most common ventilatory modalities used in intensive care units. PSV is an assisted, pressure-limited, and flow-cycled ventilatory mode. The ventilator provides assistance when the patient makes a breathing effort, and when inspiratory flow reaches a certain threshold level, cycling to exhalation occurs. PSV unloads respiratory muscle effort, while allowing the patient to retain control over the respiratory rate and tidal volume. Withdrawal from mechanical ventilation should be performed with a gradual reduction of levels of support until extubation. Asynchronies can be present during PSV and are typically associated with high levels of support. A closed-loop modality, which adjusts support levels to keep the patient in a ‘comfort zone’, has been designed to assist in the withdrawal of mechanical ventilation. It performs at least as well as experienced medical staff and could be useful in specific groups of patients.