Thursday, March 5, 2009

APRV: Mode Classification

APRV has been classified as a time-triggered, pressure-limited, time-cycled ventilation mode.

Which provides two levels of CPAP:
  1. p-High (high pressure).
  2. p-Low (low pressure).
During two set time periods:
  1. t-High (time @ the high pressure).
  2. 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.