The acute respiratory distress syndrome (ARDS) remains a serious clinical problem with the main treatment being supportive in the form of mechanical ventilation. However, mechanical ventilation can be a double edge sword, if set improperly can exacerbate the tissue damage caused by ARDS and is known as ventilator induced lung injury (VILI). In order to minimize VILI we must understand the pathophysiologic mechanisms of tissue damage at the alveolar level. In this Physiology in Medicine paper the dynamic physiology of alveolar inflation and deflation during mechanical ventilation will be reviewed. In addition, the pathophysiologic mechanisms of VILI will be reviewed and this knowledge used to suggest an optimal mechanical breath profile (MBP - all airway pressures, volumes, flows, rates and the duration that they are applied at both inspiration and expiration) necessary to minimize VILI. Our review suggests that the current protective ventilation strategy known as the 'Open Lung Strategy' would be the optimal lung protective approach. However, the viscoelastic behavior of dynamic alveolar inflation and deflation has not yet been incorporated into protective mechanical ventilation strategies. Using our knowledge of dynamic alveolar mechanics (i.e the dynamic change in alveolar and alveolar duct size and shape during tidal ventilation) to modify the MBP necessary to minimize VILI will reduce the morbidity and mortality associated with ARDS.
- Mechanical Ventilation
- Copyright © 2017, Journal of Applied Physiology