Association Between Positive End-Expiratory Pressure at Venovenous Extracorporeal Membrane Oxygenation Initiation and Liberation Outcomes in Acute Respiratory Distress Syndrome: A Multicenter Retrospective Study

IMPORTANCE: The optimal level of positive end-expiratory pressure (PEEP) during venovenous extracorporeal membrane oxygenation (ECMO) for acute respiratory distress syndrome (ARDS) remains uncertain.
OBJECTIVES: This study aimed to evaluate the association between initial PEEP settings at ECMO initiation and the rate of successful ECMO liberation in patients with severe ARDS.
DESIGN, SETTING, AND PARTICIPANTS: We conducted a post hoc analysis of the multicenter Japan Chest CT for ARDS Requiring Venovenous ECMO (J-CARVE) registry. Adult patients with severe ARDS treated with venovenous ECMO between 2012 and 2022 at 24 institutions were included. Participants were categorized into three groups according to PEEP at ECMO initiation: low (< 8 cm H2O), middle (8–10 cm H2O), and high (> 10 cm H2O).
MAIN OUTCOMES AND MEASURES: The primary outcome was successful liberation from ECMO within 30 days. Multivariable Cox proportional hazards models were used to evaluate associations. Secondary outcomes included 60-day mortality, duration of ECMO support, and duration of mechanical ventilation.
RESULTS: Among 683 patients analyzed, the overall ECMO liberation rate at 30 days was 69.2%. Liberation rates were 57.8% (103/178), 73.5% (259/352), and 72.5% (111/153) in the low, middle, and high PEEP groups, respectively. After adjustment, the low group had a significantly lower likelihood of successful ECMO liberation (hazard ratio [HR], 0.56; 95% CI, 0.39–0.81) compared with the middle group. No significant difference was observed between the high and middle groups (HR, 0.80; 95% CI, 0.58–1.10). The low group had longer ECMO duration; however, 60-day mortality and hospital length of stay did not differ significantly among groups.
CONCLUSIONS AND RELEVANCE: Lower PEEP levels at ECMO initiation were associated with reduced likelihood of successful ECMO liberation compared with moderate PEEP, whereas estimates for high vs. moderate PEEP were not statistically significant. These findings support avoiding insufficiently low PEEP and underscore the need for prospective studies to refine optimal PEEP strategies in patients with severe ARDS.