Airway pressure release ventilation (APRV) is an alternative to mechanical methods used to aid oxygenation in patients with conditions like acute lung injury or acute respiratory distress syndrome (Daoud, 2007). It is a continuous positive airway pressure system allowing brief and intermittent releases in airway pressure (Frawley & Habashi, 2001). APRV is heralded for its ability to "allow unrestricted spontaneous breathing in any phase of the mechanical cycle," as well as to minimize the use of heavy sedatives or muscle relaxants (Petensen & Wrigge, 2004, p. 492). Other benefits to using APRV with some patients with acute lung injury or acute respiratory distress syndrome include the fact that it may decrease the risk for barotrauma and alveolar damange due to APRV providing "better alveolar recruitment at a lower end-inflation pressure," (Myers & Macintyre, 2007, p. 452). APRV may also minimize the potential for ventilator-induced lung injury (VILI) by using lung protective strategies (Daoud, 2007). Both oxygenation and efficient CO2 clearance is achieved with APRV, and it can therefore be a preferable system to other mechanical methods. Research has revealed APRV contributes to improved pulmonary gas exchange, as well as improved blood flow and oxygen supply to the tissue (Putensen & Wrigge, 2004). However, the quality...

For one, APRV begins cycling at an elevated baseline pressure, whereas standard mechanical ventilators begin at baseline pressure (Frawley & Habashi, 2001). Thus, standard mechanical ventilators require an elevation of airway pressure from the baseline in order to achieve the goal of tidal ventilation. APRV, on the other hand, starts at an elevated (plateau-level) pressure and follows with deflation to achieve the same goal (Frawley & Habashi, 2001). Spontaneous breathing can occur at different stages of the process, mainly at the plateau and deflation stages. This allowance for unrestricted breathing, in accordance with the "open lung" approach, makes it an attractive option (Daoud, Farag & Chatburn, 2012). The APRV cycle can be patient-triggered, but are usually time-triggered based on pressure levels set by the clinician (Myers & Macintyre, 2007).
It is important to understand the mechanisms by which APRV works to determine its suitability for patients, and also to distinguish between types of APRV systems. Particularly, it is important to differentiate between APRV and biphasic positive airway pressure (BIPAP), and…