The association between mechanical power within the first 24 hours and ICU mortality in mechanically ventilated adult patients with acute hypoxemic respiratory failure: A registry-based cohort study

Despite the widespread adoption of lung-protective ventilation strategies, mortality among patients on 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 acute respiratory distress syndrome (ARDS). However, the impact of MP on intensive care unit (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. 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"? 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 on 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. Of the 21,714 patients in our registry, 9,031 (42%) met the inclusion criteria. After adjusting for baseline characteristics, high MP was associated with increased ICU mortality (odds ratio 1.58 [95% CI: 1.44, 1.72]), with a non-linear dose-response relationship. No consistent "safe" MP threshold was identified. High MP was also associated with lower extubation rates and fewer ventilator-free days. 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 potential strategy to improve outcomes, warranting exploration in clinical trials.