The term HODAD, Hands of Death and Destruction, is actually derived from a memoir by Dr. Marty Makary, "Unaccountable: What Hospitals Won't Tell You and How Transparency Can Revolutionize Health Care", on which the show is based. According to said book, there is a HODAD in every hospital which is a major source of patient harm.
Dr. Randolph Bell said " "See One, Do One, Teach One". It actually refers to a quote by Dr. William Halsted, the man who founded the surgical residency program at Johns Hopkins University.
One of the show's creators, Roshan Sethi, was an actual resident. He works now as a palliative radiation oncologist at Brigham and Women's Hospital at Harvard Medical School, where he completed his residency. Neither Sethi nor his partner Hayley Shore continued on the show or wrote another episode after co writing the pilot with Amy Holden Jones, who has been on the show for every episode and writes many episodes every season. Multiple doctors are writers on staff of the show.
The stand-in for the outside and aerial views of the hospital is Atlanta's High Museum of Art, part of the Woodruff Arts Center.
The first diagnosis is for lupus. In the popular TV medical drama House (2004), there was a long running joke about a diagnosis never being lupus.