Abstract
INTRODUCTION: Mechanical power (MP) quantifies the energy delivered from a ventilator to the respiratory system and is a key contributor to ventilator-induced lung injury. This study evaluated the association between MP and mortality in patients with acute respiratory distress syndrome (ARDS), and examined whether this relationship differs across data-driven ARDS phenotypes. METHODS: Patients with ARDS requiring invasive ventilation were identified from the MIMIC-IV database. The association between MP and mortality was assessed using logistic regression, Kaplan-Meier survival analysis, and Cox proportional hazards models. The optimal MP threshold was determined using maximally selected rank statistics. Unsupervised clustering was used to identify ARDS phenotypes and evaluate phenotype-specific responses to MP. RESULTS: A total of 1,333 patients were included. An MP < 18.7 J/min was associated with significantly lower 28-day mortality. Among MP components, the elastic-dynamic component showed the strongest association with mortality; the elastic-static component had a weaker association, and the resistive component was not significant. Respiratory rate was the strongest predictor of mortality. Three phenotypes were identified. Phenotype I (mechanical stress-dominant): poor respiratory mechanics and the highest mortality. Phenotype II (oxygenation-preserved with mild inflammation): better oxygenation, less organ dysfunction, and the lowest mortality. Phenotype III (systemic hyperinflammation with metabolic dysregulation): significant laboratory abnormalities, strong association with high MP, and increased mortality. DISCUSSION: High mechanical power (MP) was independently associated with increased mortality in patients with ARDS. An MP threshold of 18.7 J/min demonstrated prognostic relevance for mortality risk stratification, and the association between MP and outcomes varied across ARDS phenotypes, highlighting the potential value of phenotype-informed ventilation strategies.