Modern ventilators provide a 'super breath' every couple of minutes to reopen alveoli, similar to physiological sighs.

“But there was a relatively high mortality rate. It was a bit of a mystery and one solution was to just give bigger breaths. They gave bigger breaths and the mortality rate dropped. And it wasn't until I think it was the 50s where they realized that they didn't have to increase every breath to be big. What they needed to do is every so often they to have one big breath. So they have a couple of minutes of normal breaths and then one big breath just mimicking the physiological size. And there the mortality rate drops significantly.”