25 NBC had some reservations about the show before it premiered.​​

The very first screening of the ER pilot for executives did not go well. “When the lights came up, it was not a very positive reaction,” Kevin Reilly, who was NBC’s VP of drama development at the time, told EW. He recalled that Don Ohlmeyer, NBC’s west coast president at the time, was so unhappy that he “stormed out of the room. Once Don had declared that he was less than happy with it, that kind of set the tone.” Concerns at the time were numerous: Execs worried that the show was too gory, that its script was too full of medical jargon, that it moved too fast and featured too many characters. “All the things that ended up becoming the hallmarks of the series,” executive producer John Wells noted.