Power, Duration, and Compliance: Reframing Risk of Ventilatory-Induced Lung Injury With the Risk-Adjusted Mechanical-Power Score

OBJECTIVES: Static thresholds for mechanical power (MP) may not prevent ventilator-induced lung injury because risk depends on exposure duration and the underlying respiratory compliance. We aimed to quantify how MP intensity and exposure duration interact with respiratory compliance to predict oxygenation changes consistent with acute respiratory distress syndrome worsening or 14-day mortality. DESIGN: A retrospective analysis of 2 large intensive care datasets. SETTING: ICUs in the Netherlands and the United States from 2003 to 2016 and 2008 to 2019, respectively. PATIENTS: Mechanically ventilated adults with oxygenation levels consistent with moderate to severe acute respiratory distress syndrome. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Time-dependent Cox proportional hazards models stratified by respiratory compliance estimated the hour-specific associations of immediate exceedance and cumulative time above MP thresholds with the primary outcome. Estimated effects were integrated into a risk-adjusted mechanical-power score. Among 2150 mechanically ventilated acute respiratory distress syndrome patients risk from MP exposure was dictated by respiratory compliance: in higher-compliance lungs, risk followed a dose-response pattern, with immediate hazard beginning at 10 J/min (hazard ratio = 1.04) and cumulative harm amplifying significantly over time. Conversely, for low-compliance patients, risk was confined to a narrow power band (11-20 J/min) without evidence of cumulative harm. With risk-adjusted MP score as a predictor of outcome eXtreme Gradient Boosting yielded an area under the receiver operating characteristic curve of 0.863. CONCLUSIONS: A single "safe" MP threshold is insufficient for guiding ventilation; the risk of lung injury is governed by a dynamic interplay of power intensity, duration, and the patient's respiratory compliance. The risk-adjusted MP score unifies these factors into a time-varying, clinically interpretable metric that warrants prospective validation for personalized ventilator management.