Optimizing mechanical ventilation: Personalizing mechanical power to reduce ICU mortality - a retrospective cohort study

Abstract

Background: Mechanical ventilation, a crucial intervention for acute respiratory distress syndrome (ARDS), can lead to ventilator-induced lung injury (VILI). This study focuses on individualizing mechanical power (MP) in mechanically ventilated patients to minimize VILI and reduce ICU mortality.

Methods: A retrospective analysis was conducted using the Amsterdam University Medical Centers Database (AmsterdamUMCdb) data. The study included patients aged 18 and older who needed at least 48 hours of pressure-controlled mechanical ventilation. Patients who died or were extubated within 48 hours and those with inadequate data were excluded. Patients were categorized into hypoxemia groups based on their PaO2/FiO2 ratio. MP was calculated using a surrogate formula and normalized to ideal body weight (IBW). Statistical analyses and machine learning models, including logistic regression and random forest, were used to predict ICU mortality and establish safe upper limits for IBW-adjusted MP.

Results: Out of 23,106 admissions, 2,338 met the criteria. Nonsurvivors had a significantly higher time-weighted average MP (TWA-MP) than survivors. Safe upper limits for IBW-adjusted MP varied across hypoxemia groups. The XGBoost model showed the highest predictive accuracy for ICU mortality. An individualization method for mechanical ventilation settings, based on real-time physiological variables, demonstrated reduced predicted mortality in a subset of patients.

Discussion: Elevated TWA-MP is associated with increased ICU mortality, underscoring the need for personalized mechanical ventilation strategies. The study highlights the complexity of VILI and the multifactorial nature of ICU mortality. Further studies to define a safe upper limit for IBW-adjusted MP may help clinicians optimize mechanical ventilation settings and decrease the risk of VILI and mortality.

Conclusions: Despite the fact that the study's retrospective design and reliance on a single-center database may limit the generalizability of findings, this study offers valuable insights into the relationship between mechanical power and ICU mortality, emphasizing the need for individualized mechanical ventilation strategies. The findings suggest a potential for more personalized, data-driven approach in managing mechanically ventilated patients, which could improve patient outcomes in critical care settings.

Fig 1. An overall scheme of the individualization process of mechanical ventilation setting.

ICU: Intensive care unit. PEEP: Positive end-expiratory pressure. VE: Minute ventilation. MP: Mechanical power. TV: Tidal volume.

Fig 2. Patient inclusion flow chart.

Fig 3. COX-survival curve according to the found safe limits of 48 h-TWA, IBW-adjusted MP.

Stratified into hypoxemic levels: nonhypoxemic (top left), mildly hypoxemic (top right), moderately hypoxemic (bottom left), and severely hypoxemic (bottom right). TWA: Time-weighted average. IBW: Ideal body weight. MP: Mechanical power.

Fig 4. SHAP values display the sensitivity of the XGBoost model in predicting ICU mortality against different covariables.

TWA: Time Weighted Average. APPT: Activated Partial Thromboplastin Clotting Time. ASAT: Aspartate Aminotransferase. MP: Mechanical power. IBW: Ideal Body Weight. PEEP: Positive End Expiratory Pressure.