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Mechanical power ratio threshold for ventilator-induced lung injury
Rosanna D'Albo1,2, Tommaso Pozzi1,3, Rosmery V Nicolardi1,4
1Department of Anesthesiology, University Medical Center Göttingen, Göttingen, Germany.
Intensive Care Medicine Experimental
|July 30, 2024
Summary
A mechanical power ratio (MPratio) above 4.5 indicates a threshold for ventilator-induced lung injury (VILI) in healthy pigs. This finding helps quantify VILI risk during mechanical ventilation.
Area of Science:
- Critical Care Medicine
- Pulmonary Physiology
- Biomedical Engineering
Background:
- Mechanical power (MP) integrates causes of ventilator-induced lung injury (VILI).
- MP is expressed as a ratio of observed to normal expected values (MPratio).
Purpose of the Study:
- To define a threshold value of MPratio associated with VILI development.
- To establish a quantitative risk marker for VILI.
Main Methods:
- Studied 82 healthy pigs under mechanical ventilation for 48 hours.
- Assessed VILI using histological variables and unsupervised cluster analysis.
- Determined a threshold MPratio of 4.5 for VILI development.
Main Results:
- An MPratio threshold of 4.5 correlated with increased lung injury, edema, and fluid imbalance (p < 0.001).
- MPratio clusters above and below 4.5 showed significant differences in respiratory system elastance, pulmonary artery pressure, and dead space (p < 0.001).
- Changes in driving pressure, lung elastance, and other hemodynamic variables were significantly worse in the high MPratio group (p < 0.001).
Conclusions:
- MPratio serves as a physiological metric to quantify VILI risk.
- An MPratio > 4.5 appears to be a threshold for VILI in healthy lungs after 48 hours of ventilation.
- The VILI threshold may differ in humans and in pre-injured lungs.
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