The title "The Room Where It Happens" comes from the musical Hamilton, the mega-hit that broke many Broadway records.
Except for the memory fragments, the entire episode takes place inside an OR.
Caterina Scorsone gave birth to her 2nd child just two days before the airing of this episode.
Although ITP (idiopathic thrombocytopenia) is an autoimmune disease, it can only be diagnosed by excluding everything else. There is no test for ITP. Also, ITP means there is a shortage of (perfectly working) platelets and not disfunctional platelets as described in this episode.