Outcome and Oxygenation Response to Airway Pressure Release Ventilation (APRV) Used as a Rescue Strategy for Severe Hypoxemic Respiratory Failure—An Observational Study

Background and objectives: Airway pressure release ventilation (APRV) is an inverse ratio ventilation often used as a rescue method for patients with severe acute hypoxemic respiratory failure (AHRF). This observational cohort study aims to evaluate the outcomes of APRV for patients with severe AHRF. Methods: We conducted a retrospective observational cohort study of patients with AHRF requiring APRV. The primary outcome was early physiological response, defined as the change in PaO2/FiO2 (P/F ratio) within 6 h of APRV initiation. Secondary outcomes included ICU mortality, duration of mechanical ventilation, and length of stay. Results: Between 01/2018 and 09/2024, 152 patients had APRV initiated for >2 h. P/F ratio improved in 64% of patients (responders). Responders had more severe hypoxemia before APRV initiation (P/F ratio 9.8 vs. 10.4 kPa, p = 0.05) and showed a greater improvement within 6 h following APRV initiation (18.8 vs. 11.9 kPa, p < 0.01). Overall survival to ICU discharge was 56%. There were no differences in ICU survival or liberation from mechanical ventilation between responders and non-responders (log-rank p = 0.48 and 0.96). There were also no differences in improvement in oxygenation following APRV or mortality between COVID-19 and non-COVID-19 patients. Conclusions: APRV may improve oxygenation in the short term, but this improvement in oxygenation was not associated with improved clinical outcomes in this observational cohort.