The brain-dead patient's name is Ray Bolger which is the name of the actor who played Scarecrow in The Wizard of Oz.
Referenced during "Maniac" song
Carla says it's a stupid sitcom
JD's continued line "I'm not even supposed to be here today!"
Mentioned in dialogue
Homage parodied: music band Toto, reference to the dog's name; J.D. drove into a "mysterious tunnel" before appearing a place where "he shouldn't be at", had his shoes painted red, called "Dorothy"; The quadruple goes on a quest to get "brain", "heart" and "courage"; Jordan, usually cynical, referred as "Evil witch of the East Wing(Wind)", her melting off as the ending; quests resolved with the characters "having it all along"; ending song "Somewhere over the rainbow"