Abstract
Mechanical ventilation stands as a life-saving intervention in the management of respiratory failure. However, it carries the risk of ventilator-induced lung injury. Despite the adoption of lung-protective ventilation strategies, including lower tidal volumes and pressure limitations, mortality rates remain high, leaving room for innovative approaches. The concept of mechanical power has emerged as a comprehensive metric encompassing key ventilator parameters associated with the genesis of ventilator-induced lung injury, including volume, pressure, flow, resistance, and respiratory rate. While numerous animal and human studies have linked mechanical power and ventilator-induced lung injury, its practical implementation at the bedside is hindered by calculation challenges, lack of equation consensus, and the absence of an optimal threshold. To overcome the constraints of measuring static respiratory parameters, dynamic mechanical power is proposed for all patients, regardless of their ventilation mode. However, establishing a causal relationship is crucial for its potential implementation, and requires further research. The objective of this review is to explore the role of mechanical power in ventilator-induced lung injury, its association with patient outcomes, and the challenges and potential benefits of implementing a ventilation strategy based on mechanical power.
Key Points
- Definition of Mechanical Power: MP quantifies the energy transferred from the ventilator to the respiratory system, expressed in Joules per minute, integrating multiple ventilatory parameters.
- Mechanisms of VILI: Includes volutrauma, barotrauma, atelectotrauma, and biotrauma, with MP summarizing the mechanical forces contributing to these injuries.
- Clinical Evidence: Studies demonstrate a correlation between higher MP and worse outcomes, including increased VILI incidence and higher mortality in ARDS and other respiratory failure patients.
- Challenges in Implementation: MP calculation at the bedside faces challenges due to complex formulas, variability in measurement methods, and the lack of standardized thresholds.
- Dynamic Mechanical Power: This variant enables real-time monitoring without requiring inspiratory holds, improving accessibility for all ventilated patients.
- Thresholds and Outcomes: Current data lack consensus on MP thresholds for VILI mitigation, with values above 12–25 J/min associated with adverse effects in experimental and clinical studies.
- Ventilation Strategies: Lung-protective strategies incorporating MP aim to optimize ventilatory parameters, balancing the need for adequate ventilation and reduced lung stress.
- Experimental Insights: Animal models and clinical trials link MP reduction to decreased histological lung damage and mortality, but causality remains unconfirmed.
- Integration into Practice: Automated ventilator tools for MP measurement are needed to streamline its use, enhance decision-making, and guide individualized ventilation.
- Future Directions: Further randomized controlled trials and validation studies are required to establish MP as a standard metric for optimizing mechanical ventilation.
