Dead Man's hanging tube? Imaginarium of Dr. Parnassus?

In the movie, the Imaginarium of Dr. Parnassus by Terry Gilliam starring Heath Ledger, Johnny Depp, Colin Ferrel, Jude Law, Andrew Garfield, aka the hottest cast of characters ever....is the metal tube that prevents the "Tony" character from dying while hanging a real thing that actually works? I don't plan on trying it, I was just wondering if its real historically or something and what it might be called.