1994. Some emergency physicians were still in high school back when NBC’s show “ER” debuted, introducing the world to CBCs, difibrilators and George Clooney’s five o’clock shadow. Fifteen years, five Emmys and gallons of fake blood later that staple of Thursday night programming finally came off the air this spring. Twelve EPs, from a textbook writer to an ED chairman, reflect  on how the show impacted their lives and changed an entire specialty.