The introduction of the active expiratory valve was a disruptive technology in critical care mechanical ventilation. This valve flutters when the airway pressure rises above the targeted level - to vent off surplus gas, but maintain airway pressure. It led to the development of newer modes of ventilation (and adjustments to older modes) that allowed the patient to breathe spontaneously independent of the ventilator. As such this was a development of intermittent mandatory ventilation (IMV) - without the risk of breath stacking and expiratory dys-synchrony.
The major mode of ventilation that evolved from the active expiratory valve has several different aliases - BiLevel, BIPAP, BIVENT, DuoPAP etc. but they are all, essentially, pressure controlled intermittent mandatory ventilation modes - that allow the patient to breathe supported or unsupported at a high (Phigh) or low (Plow) airway pressure.
I have chosen the term “Bilevel Pressure Control (BL-PC)” to describe this mode. This tutorial introduces BL-PC, from the perspective of IMV, explains the technology and then discusses the setup and use of the mode. It is a mode of ventilation that is used widely as the “default mode” in many ICUs and can be used in any patient at any time. @ccmtutorials www.ccmtutorials.org