In acute respiratory distress syndrome, what will happen to the lung compliance ?

Lung : Compliance goes down, positive end pressure may help keep easily collapsing alveoli open.

It will increase: Lung compliance is how "stretchy" the lung is. When it gets filled with fluid and cells, like in ards, the lung becomes less flexible, less "stretchy, " and thus less compliant. Consequently, it becomes harder to inflate the lung and breathe, hence the shortness of breath.

Decreases: The lung is filled with inflammatory exudate and the compliance decreases as it cannot stretch. This is a classic, we follow that on the ventilator and adjust the settings so that we don't stress out the lungs too much. I hope this answers your question, let me know if i can provide more detail.