Correlation between mechanical power and lung ultrasound score and association with clinical outcomes in acute respiratory distress syndrome.

Abstract

Background: Mechanical power (MP) integrates tidal volume, airway pressures, flow, and respiratory rate into a single estimate of ventilatory energy delivery and serves as an integrative physiologic marker of ventilator-induced lung injury. Lung ultrasound score (LUS) is a bedside tool that quantifies lung aeration loss, reflecting the structural expression of lung injury in acute respiratory distress syndrome (ARDS). However, data correlating MP with LUS and clinically relevant outcomes in ARDS remain limited.

Aim: To explore whether MP is associated with lung ultrasound-derived aeration loss and clinical outcomes in moderate-to-severe ARDS.

Methods: This prospective observational study enrolled adult patients with moderate-to-severe ARDS requiring invasive mechanical ventilation for more than 48 hours. MP and LUS were assessed at 0, 24, 48, and 72 hours. Their association was evaluated using Pearson correlation analysis. Associations between MP and 28-day mortality and weaning outcomes were analyzed using logistic regression and receiver operating characteristic curve analysis. Mean MP was defined as the arithmetic mean across the four time points.

Results: Forty-four patients were included. MP was strongly correlated with LUS at baseline (r = 0.84, 95%CI: 0.72-0.91), 24 hours (r = 0.83, 95%CI: 0.71-0.91), 48 hours (r = 0.91, 95%CI: 0.85-0.95), and 72 hours (r = 0.93, 95%CI: 0.87-0.96) (all P < 0.001). In exploratory analyses, higher mean MP was associated with increased mortality [odds ratio (OR) = 2.11 per J/minute increase, 95%CI: 1.31-3.39] and demonstrated numerically higher area under the receiver operating characteristic curve than driving pressure (0.98, 95%CI: 0.94-1.00 vs 0.91, 95%CI: 0.82-0.98). Higher mean MP was also associated with difficult (OR = 2.20, 95%CI: 1.11-4.36) and prolonged weaning (OR = 1.61, 95%CI: 1.04-2.50).

Conclusion: MP parallels lung ultrasound-derived aeration loss in ARDS and demonstrates associations with mortality and adverse weaning, supporting its potential role as an integrative physiologic marker in individualized ventilatory management.