John Wells

Back in 1994, those of us who write about TV expended a whole lot of words on the Big Medical Drama Showdown between "ER" and "Chicago Hope."

"Chicago Hope" ran a very respectable 141 episodes over six seasons. Which makes it all the more astonishing that "ER" airs its 304th episode tonight (9 p.m., Ch. 5) as the strike-interrupted 14th season resumes.

Executive producer John Wells readily admits he never expected "ER" to turn into a monster hit, let alone run for 15 years. (NBC recently announced that next season will be its last. It will wrap things up in February 2009.)

In a conference call with TV critics, Wells said everyone was so busy working on the show it didn't sink in "that this was going to be a bit of a ride" until the end of the first season when ratings shot through the roof and cast members "went from traveling in coach to being unable to walk through the airport without our providing them with security."

But despite numerous changes in both the cast and the writing staff, "We've really tried to stay focused on just making the show good ... and just trying to do a show we were still proud of and working with actors who we think are talented ... and trying to do stories about what's really going on in the workplace."

As the show airs Episode 304, with five left to go this season and 19 (or 20) next season, Wells said he thinks that despite all the changes, "ER" is essentially what it was when it began.

"The thing that allowed it to continue as our cast members moved on was that it's really about a workplace," he said. "And a workplace that's not dissimilar from a lot of other people's workplaces, where it's very pressured, you have very close friends, your work family becomes as close to you as your own family, even though you'd never really admit that at home. And I think that's what people connected with.

"And I've been very proud of that — of the way in which we've been able to talk about issues that we thought were important and show the fallibility of the people who work there and yet still admire them for the work that they do."

ELSEWHERE ON "ER": Noah Wyle will be back next season; other former cast members might make appearances, but nothing has been set yet.

"He and I have kind of had a long-term arrangement about when the show was going to come to an end, his character returns," Wells said.

But, despite rumors, don't hold your breath on seeing George Clooney.

"A couple of other things have come up in his life. He's doing this and that," Wells joked. "I love George. He's a friend of mine. I would doubt very much that he would come back to the show."

• Maura Tierney (Abby) and Luka (Goran Visnjic) will exit before the show ends in February, although exactly when has yet to be determined. Both will be in at least some episodes next season.

"Fans of Luka and Abby should always have their tissues close by," Tierney said. "We are going to make you cry so hard. But they might be tears of joy."

• The current season will end with a cliffhanger. "Big things will blow up," Wells said.

• The show will have some sort of wrap-up. "I wanted to really have the opportunity to write it correctly on its way out," Wells said.

• Will there be a spinoff? "No," Wells said, before qualifying that to a hugely improbable maybe.