The study analyzed the association between ventilator mechanical output (MP) and mortality in 1,333 patients with acute respiratory distress syndrome (ARDS) from the MIMIC-IV database. MP below 18.7 J/min was associated with significantly lower 28-day mortality. The elastic-dynamic component of MP had the strongest association with mortality, the elastic-static component was weaker and no resistance component; the strongest predictor was respiratory rate. Using clustering, three phenotypes of ARDS were identified: Phenotype I with dominant mechanical stress, poor respiratory mechanics, and highest mortality; Phenotype II with preserved oxygenation, moderate inflammation, less organ dysfunction and lowest mortality; Phenotype III with systemic hyperinflammation, metabolic dysregulation, laboratory abnormalities and a strong association with high MP and increased mortality. High MP was independently associated with increased mortality, and a threshold of 18.7 J/min had prognostic relevance for mortality risk. The association between MP and outcomes differed between phenotypes, highlighting the value of phenotypically informed ventilatory strategies.