When mechanical power remains high despite conventional lung-protective settings: a physiology-driven bedside framework.

Abstract

Mechanical power integrates ventilatory pressure, tidal volume, flow, and respiratory rate into a single estimate of the energy transferred to the respiratory system per unit time. Higher mechanical power has been associated with ventilator-induced lung injury and worse outcomes. A common bedside dilemma arises when mechanical power remains high despite conventional lung-protective settings, because further reduction of ventilator intensity may compromise gas exchange. This narrative, physiology-driven review addresses how to respond when persistently elevated mechanical power may reflect physiological constraint rather than easily modifiable ventilator settings. We outline a bedside approach in which clinicians first verify conventional lung-protective settings and then look for the main physiological factor that prevents further ventilator reduction. Reduced end-expiratory lung volume should prompt individualized positive end-expiratory pressure (PEEP) titration aimed at restoring and stabilizing lung volume while avoiding overdistension and derecruitment. In mechanically heterogeneous lungs, prone positioning and patient-specific pressure optimization may improve the physiological conditions associated with injurious ventilation, even when the global value of mechanical power cannot be safely lowered. During assisted ventilation, excessive respiratory drive and inspiratory effort should be assessed and treated when present. When high mechanical power remains unavoidable despite optimized settings and targeted physiological interventions, extracorporeal support may be required to enable ultra-protective ventilation.