With the current lack of magic bullets to treat BPD, some affected infants get a long list of pharmaceuticals...

A new acquaintance for me  is montelukast.

A Pubmed-search did not convince me much, I found only two clinical studies: one positive and one negative. Also found an experimental study from 2016, suggesting that the idea of leukotrien-inhibition may be plausible though.

Do you use it for BPD-treatment (manifest BPD)?

I had not even heard of the practice until I saw your post.  I have worked in 5 large academic NICUs around the US without encountering this.