Yes, there are teams of physicians which investigate medical “miracles” and their job is to say whether or not there is a natural explanation for them. If not, they are passed to theologians who determine whether there was evidence of divine intercession.
I don’t know the story about Lourdes, but I do know the atheist doctor who was investigating Padre Pio converted.
This is a book that is supposed to be good on the topic. (I haven’t read it, but it has gotten good reviews.)
Making Saints: How the Catholic Church Determines Who Becomes a Saint, Who Dosen’t, and Why by Kenneth L. Woodward
Does this answer your question?