Airway pressure release ventilation

[5] Based on clinical and experimental data, airway pressure release ventilation is indicated in patients with acute lung injury,[6][7] acute respiratory distress syndrome[8][9] and atelectasis[1] after major surgery This is a type of inverse ratio ventilation.

Mean airway pressure on APRV is calculated by this formula:[1] Different perceptions of this mode may exist around the globe.

While 'APRV' is common to users in North America, a very similar mode, biphasic positive airway pressure (BIPAP), was introduced in Europe.

Although similar in modality, these terms describe how a mode is intended to inflate the lung, rather than defining the characteristics of synchronization or the way spontaneous breathing efforts are supported.

[8][15] Concern has been raised about the amount of mechanical power applied to the lung during APRV and the risk of ergotrauma, especially in pulmonary ARDS.

A pressure-time graphic
Static pressure-volume curve during volume-controlled mechanical ventilation. High pressure ('P high') is set below the high inflection point (HIP) and low pressure is set above the low inflection point (LIP). [ 1 ]
Corresponding pressure and flow curves during one cycle of inflationdeflation. Notice the flow curve goes back to zero at the end of inflation, indicating full lung inflation; and also goes back to zero during the release period before inflation starts, indicating complete gas exhalation with no intrinsic PEEP. [ 1 ]
Pressure-time curve for APRV. 'P high' is the high CPAP, 'P low' is the low CPAP, 'T high' is the duration of 'P high,' and 'T low' is the release period or the duration of 'P low.' Spontaneous breathing appears on the top of 'P high.' [ 1 ]