From the Research
Airway Pressure Release Ventilation (APRV) is recommended for patients with severe lung injury or ARDS who need improved oxygenation while minimizing ventilator-induced lung injury. The most recent and highest quality study, 1, published in 2020, demonstrates the effectiveness of APRV combined with prone positioning in improving oxygenation in patients with ARDS. Initial APRV settings typically include a high pressure (P-high) of 20-35 cmH2O based on patient ideal body weight and lung compliance, with a long time at high pressure (T-high) of 4-6 seconds to maintain alveolar recruitment.
- The release pressure (P-low) should be set at 0-5 cmH2O to allow for CO2 removal, with a very brief release time (T-low) of 0.2-0.8 seconds, typically starting at 0.5 seconds and adjusted based on expiratory flow.
- The T-low should be set to terminate at 50-75% of peak expiratory flow to prevent alveolar collapse.
- Patients require close monitoring of work of breathing, oxygenation (target SpO2 88-95%), ventilation (pH >7.25), and hemodynamics. APRV works by maintaining a continuous positive airway pressure with brief releases, allowing spontaneous breathing throughout the respiratory cycle. This approach promotes alveolar recruitment, improves ventilation-perfusion matching, reduces dead space ventilation, and may decrease sedation requirements compared to conventional ventilation modes.
- Gradual weaning involves reducing P-high by 2-3 cmH2O increments while monitoring patient tolerance before transitioning to conventional modes, as supported by earlier studies 2, 3, 4, 5.