A comprehensive review of the use and understanding of airway pressure release ventilation

ABSTRACT

Introduction: Airway pressure release ventilation (APRV) is a mode of ventilation typically utilized as a rescue or alternative mode for patients with acute respiratory distress syndrome (ARDS) and hypoxemia that is refractory to conventional mechanical ventilation. APRV’s indication and efficacy continue to remain unclear given lack of consensus amongst practitioners, inconsistent methodology for its use, and scarcity of convincing evidence.

Areas covered: This review discusses the history of APRV, how APRV works, rationales for its use, and its theoretical advantages and disadvantages. This is followed by a review of current available literature examining APRV’s use in the intensive care unit, with further focus on its use in the pediatric intensive care unit.

Expert opinion: APRV is a ventilation mode with theoretical risks and benefits. Appropriate study of APRV’s clinical efficacy is difficult given a heterogeneous patient population and widely variable use of APRV between centers. Despite a paucity of definitive evidence in support of either mode, it is possible that the use of APRV will begin to outpace the use of high-frequency oscillatory ventilation (HFOV) for the management of refractory hypoxemia as more attention is paid to benefits of spontaneous breathing and minimizing sedation. Furthermore, APRV’s role during ECMO deserves further investigation.

KEYWORDS:

• Acute lung injury
• airway pressure release ventilation
• acute respiratory distress syndrome

Article highlights

• APRV is often viewed as a rescue mode for patients with ARDS and inadequate oxygenation, with the goal of maximizing lung recruitment while avoiding overdistension that could create lung injury.

• There is lack of consensus and evidence regarding its clinical indication and efficacy.

• APRV is a time-cycled, pressure-controlled, intermittent mandatory ventilation mode with extreme inverse I:E ratios that allow unrestricted spontaneous breathing.

• Time-controlled adaptive ventilation is the most widely accepted protocol used to guide ventilator settings and strategy when utilizing APRV.

• Presumed advantages of APRV include lung-protective recruitment, unrestricted spontaneous breathing, hemodynamic stability, and reduced sedation requirement.

• Concerns about APRV use include volutrauma, atelectrauma, and exposure to high transpulmonary and transvascular pressures.

• Clinical studies evaluating efficacy of APRV have yet to yield convincing results that show improvement in meaningful clinical outcomes.

• A recent pediatric clinical trial comparing CMV to APRV was terminated early given increased mortality in APRV group, although there were differences in baseline characteristics between the groups.

• Widespread use of APRV as a primary mode of ventilation for patients with ARDS will require both definitive evidence supporting its benefits, as well as a more standardized ventilator strategy.

• Given recent emphasis on and awareness of delirium and deleterious effects of sedation medication and neuromuscular blockade, APRV may begin to be looked upon more favorably, particularly when being considered against HFOV, which requires far deeper sedation levels and often neuromuscular blockade.

• Study of APRV use during ECMO is certain to gain traction in the coming years, given that it has been somewhat unexplored to date.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

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Funding

This paper was not funded.