Background: Despite the widespread adoption of lung-protective ventilation strategies, mortality among patients receiving invasive mechanical ventilation (IMV) remains high. Mechanical power (MP) integrates various variables responsible for ventilator-induced lung injury and has been associated with mortality in patients with ARDS. However, the impact of MP on ICU mortality in the larger group of patients with acute hypoxemic respiratory failure (AHRF) has not been well established, and previous studies have reported inconsistent thresholds for predicting outcomes.

Research question: Is high MP (> 17 J/min) within the first 24 hours of IMV, calculated using dynamic driving pressure, associated with ICU mortality in patients with AHRF? Additionally, does a threshold exist below which IMV is considered safe?

Study design and methods: In this multicenter cohort study, we included adult patients with AHRF who received IMV. Patients were excluded if they received IMV for > 24 hours before inclusion or were receiving extracorporeal life support. We applied multivariable logistic regression models with inverse probability of treatment weighting and used change-point regression models with restricted cubic splines.

Results: Of the 21,714 patients in our registry, 9,031 patients (42%) met the inclusion criteria. After adjusting for baseline characteristics, high MP was associated with increased ICU mortality (OR, 1.58; 95% CI, 1.44-1.72), with a nonlinear dose-response relationship. No consistent safe MP threshold was identified. High MP also was associated with lower extubation rates and fewer ventilator-free days.

Interpretation: In this study, exposure to high MP within the first 24 hours of IMV was associated with increased ICU mortality in patients with AHRF. The absence of a consistent safe threshold suggests that reducing MP at IMV initiation may be a strategy to improve outcomes, warranting exploration in clinical trials.