The thing that sticks with me about “;ER”; was this sense of hurtling, of momentum and velocity, the crucial crush of time running out. The doctors in the show have to make snap decisions in seconds and then have to live by the consequences. It's like combat, in a way, and “;ER”; was paced like a pitched battle, with uneasy lulls in the shelling, when a dog-tired joe could grab a smoke and a moment of reflection. Inevitably — you could count on it — the assault would begin anew.

I recall one early episode distinctly. The doctors were trying to save a mother and baby, and procedures kept failing, and they kept trying new tacks, refusing to give up. I don't remember whether they were successful. But I do remember that I forgot to breathe for an hour.

Still one of the most watched dramas on NBC, “;ER”; bows out this week after 15 years and more than 300 episodes. When “;ER”; came along in the early '90s, it was considered a class act from the get-go, aided by a boost from Amblin Entertainment head Steven Spielberg and the show's creator, Michael Crichton, the pair of them on a high after “;Jurassic Park.”;

Crichton, a thriller writer with a medical degree, never met a scientific buzz he couldn't incorporate. He learned early on that the emergency room was being transformed into the front line of American medical practice, and “;ER”; rode the crest of interest in health care. During the time “;ER”; was on the air, the family doctor pretty much disappeared, and the corporate or state-run faceless medical center had become the norm. He understood also that the people who staffed such facilities were essentially highly trained — albeit disposable — soldiers subject to stress jitters and fatigue.

The situation was core of the drama, not the characters. The situation was the monster at the gates, ready to gobble them up.

The characters were allowed to change, to burn out, to become heroes, sometimes all at once. The pressure-pot atmosphere contributed greatly to the atmospherics — producer John Wells' did a masterful job of suggesting manic claustrophobia every week. You notice how the characters seemed to take a deep, calming breath every time they left the waiting rooms, even just to stand around the loading dock?

“;ER”; was also intimate in a way that only television can be, and deliberately shot in a verite manner that foreshadowed hand-held-camera reality shows. It also was never squeamish about blood, injury or doctor-talk — Crichton refused to dumb down the technical dialogue — and generally treated death with resigned dignity. Just in the mature way death was presented, as a consequence of life, “;ER”; was a show that didn't play up the adolescent nonsense that passes for scripting.

Characters came and went, and their side issues passed for continuity — romances, drug use, office politics, etc. — particularly in the middle of the show's run, when someone decided it appealed mostly to women and plenty of soap-opera hysteria was ladled on.

But the central, hair-raising pleasure of “;ER”; remained the sprawling mess of humanity struggling to cope with injury, sickness and each other, set in a whirling, tiny universe where seconds count.

As “;ER”; has counted down this last season, many of the original characters have returned in cameos. Interestingly, these doctors and nurses seem to have a Zen-like glow about them, as if they had passed through the fire and emerged relatively unburned. Good lesson there.

MEDICAL TERMS YOU'LL MISS

» STAT!: Slang expression for move your butt, doc!

» Triage: The system of prioritizing patients in an emergency situation where a whole bunch of people are hurt or sick. You know, it's like taking a number at your local deli.

» Intubation: The procedure of inserting a long tube into the trachea (wind pipe area) of a patient who isn't breathing.

» Code brown: Term for when a patient doesn't make it to the bathroom in time. In the real world, we just say “;Ewwww.”;

» Tox screen: Blood test to determine which drugs are in a patient's system.