Mechanical Power and Ventilator Variables in Patients With Acute Respiratory Distress Syndrome: A Pilot Prospective Cohort

Background: Mechanical power (MP) integrates multiple ventilatory variables and reflects the total energy transferred to the lungs during mechanical ventilation, potentially contributing to ventilator-induced lung injury (VILI) in acute respiratory distress syndrome (ARDS). This study evaluated the association between MP, ventilatory variables, and mortality in patients with ARDS. Methods: In this prospective cohort study conducted between May 2025 and May 2026, 50 mechanically ventilated patients with ARDS were enrolled and categorized into survivors (n=25) and non-survivors (n=25). Ventilatory parameters, arterial blood gas (ABG) variables, and MP components were serially recorded. Chest computed tomography (CT) was performed for quantitative lung aeration analysis. Mechanical power was calculated using static, dynamic, and resistive components. Results: Non-survivors had significantly higher Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores (p<0.0001). They demonstrated worse oxygenation, higher partial pressure of carbon dioxide (PaCO₂) and lactate levels, lower compliance, and significantly elevated ventilatory pressures and MP indices. Day 1 total MP, dynamic MP, and resistive MP were significantly greater among non-survivors (p<0.0001). Average ventilatory parameters during ICU stay showed persistent elevation of respiratory rate (RR), plateau pressure (PP), driving pressure (DP), and total MP in non-survivors. CT-derived aeration parameters did not differ significantly between groups. Multivariate regression identified average pressure of arterial oxygen (PaO₂), PaO₂/fraction of inspired oxygen (FiO₂) (P/F) ratio, day 1 static compliance (SC), plateau pressure, static MP, average peak inspiratory pressure (PIP), and average total MP as independent predictors of mortality. Conclusion: Increased mechanical power and adverse ventilatory mechanics were strongly associated with mortality in ARDS. Continuous optimization of ventilatory parameters and reduction of cumulative mechanical energy delivery may improve outcomes in mechanically ventilated patients with ARDS.