The two main aspects of protective mechanical ventilation are to limit tidal volume ( V T) and plateau pressures to prevent lung damage caused by overdistension and to set the appropriate positive end-expiratory pressure (PEEP) level to minimize the cyclic opening and closing of airways and lung units. Increasing understanding of the mechanisms behind VILI has led to the development of the concept of protective mechanical ventilation. More recently, the ‘unifying’ concept of ergotrauma (damage because of excessive mechanical energy) has been developed and the mechanical power has been proposed as a single variable encompassing all the factors involved in VILI development. The main ‘classical’ determinants of VILI are barotrauma and volutrauma, that occur because of high volumes or pressures atelectrauma and biotrauma occur at lower lung volumes by the cyclic opening and closing of lung units. At the same time, extensive studies have demonstrated that the inappropriate application of mechanical ventilation can worsen/induce lung injury (so-called ‘ventilator induced lung injury’ (VILI)). Mechanical ventilation is a lifesaving technique in several forms of acute respiratory failure. LUNG PROTECTIVE MECHANICAL VENTILATION IN ACUTE RESPIRATORY DISTRESS SYNDROME Before that, however, we shall briefly review the state of the art of lung protective ventilation in ARDS. A wide debate among experts in the field followed and fuelled a number of important studies that we will review in the second part of this article. These doubts, which are still partially unsolved, led many to the conclusion that ‘atypical’ ARDS does not need ‘typical’ lung protective ventilation. Most of these conclusions were based on the observation that COVID-19 patients showed ‘abnormally high’ levels of static compliance and lung volumes and ‘abnormally low’ oxygenation parameters, not totally justified by the amount of nonventilated parenchyma on computed tomography (CT) scan. However, in a matter of weeks, clinical observations and expert opinions began to emerge, suggesting that COVID-19-ARDS was in fact a different form of ARDS. As the first cases of COVID-19 began to emerge in early 2020, it became clear that the consistent observation of bilateral interstitial pneumonia and severe hypoxemia allowed to classify the most severe cases of COVID-19 as having ARDS.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |