@Dave Vicks Could you make it clearer what it is you are looking for here please?
Is it someone with the initials "ER" who wrote a play/book about Chicago in 1982?
Is it the ER (Emergency Room) franchise? That TV show was created by Michael Crichton, though if there were a play or books (this here is a book search forum) then I don't know who would have written them. And that was from 1994.
There was a play written in 1982, "E/R Emergency Room," performed at the Organic Theater, North Clark Street, Chicago. Is that it?
Sorry, but I don't know the author.
There was also TV show called the "Chicago Story" that aired in 1982 and featured an E/R. There were TV documentaries and a film about the murders in Chicago in 1982, when Tylenol capsules were laced with Cyanide.
Then there is also the popular West End/Broadway musical "Chicago". No ER there and written in 1975. It's an American musical with music by John Kander, lyrics by Fred Ebb, and book by Fred Ebb and Bob Fosse.