The essential differences between APRV and Baum's Bi-Phasic ventilation--which he termed BIPAP--rest in the mean airway pressure and in the duration and the nature of the floor under the low pressure phase.
APRV is open to the same concern regarding tidal collapse during circuit decompression.
Almost from the start, opponents to APRV voiced their concern regarding several potentially important issues.
After more than 20 years, neither APRV nor BIPAP (bi-level) has taken over as the dominant mode of choice for ventilating ARDS.
Vocal supporters from a relatively small number of centers experienced with routine APRV use are convinced that most of us are missing out on a great and underappreciated management tool.
By dropping the higher pressure and stretching the period between release cycles, APRV can be used as one mode for all phases of ventilatory support, from the initial acute period right through the weaning phase into low level CPAP.
APRV fashions tidal "volume" swings via pressure release; from Phigh to Plow.
When a patient is being mechanically ventilated via APRV the majority of time is spent in inspiration or Phigh.
The tactile ventilator settings of APRV include two pressure levels: Phigh and Plow; as well as two time intervals: Thigh and Tlow.
The spontaneous breathing intrinsic to APRV will create diaphragmatic contractions that may enhance the recruitment of atelectatic alveoli in dependent regions of the lung field.
Recent investigations comparing APRV and conventional ventilation demonstrated a few interesting clinical outcomes.