This sentence is from "Mirai Nikki" episode 4". I've seen this use in various animes but I don't get it quite right. It doesn't seem to be the object of the sentence since the object of 吹き込んでる is こと. It sounds more like a "why", but that's not the meaning of 何, right? It also doesn't seem to be an interjection since it's not alone in the sentence.
What is the grammatical function of this 何?