Pressure support ventilation
Pressure support ventilation (PSV) in a unique form of pressure based mechanical ventilatory support that supplies a clinician selected level of airway pressure during a spontaneous inspiratory effort. This pressure 'assist' during inspiration can either partially or totally unload the ventilatory muscles of the work of breathing depending upon the level of pressure selected and the patient's respiratory system impedences. Clinically, pressure support is used in two basic ways: 1) Low level PSV (2-10 cm H2O) is desgined to unload ventilatory muscles of the work of breathing imposed by high resistance endotracheal tubes; 2) High level PSV (starting at 10-50 cm H2O and then progressively lowered) is designed to gradually reload ventilatory muscles in the weaning process. The conceptual advantages to weaning with PSV include a more physiologic pressure volume configuration to spontaneous ventilatory muscle work and improved patient-ventilator synchrony.