Which provides two levels of CPAP:
- p-High (high pressure).
- p-Low (low pressure).
During two set time periods:
- t-High (time @ the high pressure).
- t-Low (time @ the low pressure).
Furthermore the ventilators release valve allows for unhindered spontaneous breathing during both the t-High & t-Low phases (aka. Bi-phasic ventilation).
Breathing Pattern
When classifying APRV based on the breathing pattern, one would classify APRV as Pressure Control-Intermittent Mandatory Ventilation (PC-IMV) with an active exhalation valve.
(Click on the picture for a larger image)
This image shows APRV with the t-High setting shorter to demonstrate that spontaneous breaths are allowed between mandatory breaths, distinguishing a IMV modality.
(Click on the picture for a larger image)
This photo shows spontaneous breathing within the mandatory breaths, this is evidence of a active exhalation valve.