Southeast University

Acute respiratory distress syndrome (ARDS) is a major cause of mortality in intensive care units. Prone position ventilation (PPV) is an important component of ARDS management and has been shown to reduce mortality in patients with moderate-to-severe ARDS. However, substantial heterogeneity exists in treatment response to PPV. Previous studies suggest that lung morphology-focal versus non-focal patterns based on chest CT-may influence responses to ventilatory strategies, but whether lung morphology modifies the effect of PPV remains unclear. In addition, the benefits and safety of PPV in patients with acute brain injury (ABI) complicated by ARDS are uncertain. Although PPV improves oxygenation, it may impair cerebral venous drainage and increase intracranial pressure, raising concerns about its use in ABI patients. Evidence from randomized trials in this population is limited and excludes patients with more severe hypoxemia or elevated intracranial pressure.
Furthermore, the optimal duration and termination criteria for PPV are not well established. While PPV improves alveolar recruitment and reduces ventilator-induced lung injury, prolonged PPV may lead to excessive sedation exposure and PPV-related complications. Identifying the appropriate timing to discontinue PPV may help balance clinical benefits and potential harms.This study is a prospective, multicenter registry enrolling patients with moderate-to-severe ARDS. The objectives are: (1) To determine whether lung morphology can guide individualized PPV strategies; (2) To evaluate the effectiveness and safety of PPV in patients with ARDS complicated by acute brain injury; (3) To investigate the optimal timing for termination of PPV through target trial emulation methods.In addition to these core objectives, the study will include other exploratory aims.

Acute respiratory distress syndrome (ARDS) is a common and life-threatening condition in intensive care units, characterized by substantial biological and clinical heterogeneity. Differences in patients' inflammatory responses, baseline immune function, and organ failure patterns contribute to variability in ARDS severity, treatment response, and clinical outcomes. Precision classification of ARDS based on biological and inflammatory characteristics may therefore be essential for improving patient outcomes. Previous analyses of randomized clinical trials have identified two reproducible inflammatory subphenotypes-"hyperinflammatory" and "hypoinflammatory"-which differ in organ dysfunction profiles, clinical trajectories, and responses to treatments such as fluid management strategies, corticosteroids, and ventilatory interventions. However, key uncertainties remain, including whether these inflammatory subphenotypes can be validated in Chinese ARDS populations, how various bedside prediction models perform in identifying these subphenotypes, and whether model-based subphenotype identification can guide individualized treatment decisions. This multicenter cohort study aims to: (1) validate inflammatory subphenotypes of ARDS using latent class analysis; (2) compare the predictive performance of existing bedside models for subphenotype identification; and (3) assess whether subphenotype assignment based on prediction models can guide individualized treatment strategies, including fluid management, PEEP titration, and corticosteroid use. In addition to these primary aims, the study may include other exploratory objectives, such as evaluating subphenotype stability over time, characterizing biological pathways associated with subphenotypes, and assessing additional treatment-response patterns to support future precision ARDS management strategies.