Airway Pressure Release Ventilation (APRV)
The key feature is, TWO LEVELS OF PEEP.
This mode can have pressure support added, or automatic tube compensation.
Expiration occurs during the low-PEEP time.
The Low PEEP time (show above to be equal to the high PEEP time) should NEVER be that long; it should be kept as low as possible to prevent de-recruitment.The patient draws breath at two different lung volumes, set by the two different pressure levels. At the high peep, the lungs are almost completely full, and the patient is breathing near vital capacity.
This mode of ventilation is usually reserved for severe ARDS. It is controversial; many believe it is of no use.