What have I learned about the lungs in 30 years?

The way of ventilating the ARDS lung deeply changed over the last 30 years, primarily due to a better understanding of physiological mechanisms involved in the mechanical ventilation, as heart and lung interaction and generation of ventilator induced lung injury. In the new century, beginning with the National Institute of Health NIH low tidal volume ventilation, a series of therapeutical approaches have been proposed and tested in ARDS, some successful, as prone position and artificial lung support in severe ARDS, some unsuccessful, as high frequency ventilation, and some still questionable and debated, as the use of higher PEEP compared to lower PEEP. At the same time, the mechanisms of ventilation induced lung injury, the primary risk of mechanical ventilation in ARDS, have been furtherly investigated both in its physical and biological components. Recently this bulk of knowledge has been embedded in the Berlin ARDS definition, which pragmatically classifies the degree of severity of the syndrome and, more important, suggests possible treatments scaled to the severity. It is not clear, however, within a certain degree of severity which criteria should guide the possible alternative treatment. As an example, in severe ARDS, prone position, extracorporeal oxygenation should be applied separately or in combination? And, more important, should these techniques be available in every hospital or concentrated in referral centers?