There is no more active or unpredictable place at Children's Hospital than the emergency room. And there is no busier time there than a Saturday night. My associate, Beth Schwinn, spent the evening of Dec. 28 watching the passing show in the Children's E.R. Her report:

It's Saturday Night Live in the Children's Hospital emergency room. This winter night, the strange and the familiar bombard the senses. The smell of warm rooms competes with the cold night air coming through the constantly opening door and with the odors of medicine.

Heart monitors are beeping; children are crying, screaming, groaning, sleeping, playing, while parents admonish them to keep still. Lights flash on the ambulances that pull up outside the door. "Rocky II" plays on television in the observation room to a more or less avid audience, where 10 children are being observed in the six-bed unit. Other children, most in pajamas, line the seats in the hall with their parents.

In one of the "code" rooms, where trauma cases are brought, a young victim of a car accident who has just arrived by helicopter from Shady Grove Adventist Hospital is surrounded by an 11-member emergency team. Down the hall, a four-year-old cries in fright, and an adolescent shouts -- gutturally, loudly and often -- for a nurse, a mother, and less intelligible wants. Meanwhile, two infants, both quiet, are taken in turn to treatment rooms. At the same time, a seven-year-old howls in the surgery room as doctors remove paper from his inner ear.

"You've been here before?" asks Dr. Chrisann Morgan, the senior resident. "Good. Then you know this is a monkey farm."

A number of parents are growing restive. Due to the press of urgent cases, those who have brought their children in for colds or earaches have been waiting for hours.

"I been here three hours," says Debra Smith of Northeast, whose son, Donnell, 7, stuffed a dime-sized wad of paper into his inner ear three days before and complained only this afternoon of pain.

Earlier, Debra Smith had waited in an emergency clinic nearer to home for five hours. But, when the staff there saw Donnell, he squirmed too much for them to remove the paper. "There were three people holding him down," his mother said. Here, he is strapped down, and the paper is quickly removed. "They understand kids here," she says. "They're patient."

In the "code" room, which is at the far end of the hall in the emergency room, doctors and nurses cluster around Sean Maxwell, the 11-year-old accident victim.

The staff seems calm and cheerful, a contrast to the urgency of Sean's flight from Shady Grove. They are trying to determine if Sean has suffered vertebra damage. They explain each step. "We're going to give you some X-rays now, okay?" asks a doctor in a Mickey Mouse sweatshirt, with koala bears swinging from her stethoscope.

In one of the treatment rooms, six-week-old Nelson Benitez, the youngest of premature twins, waits with his father, Juan. Nelson is still hooked up to the heart and respiration monitor which he had been on at home.

Nelson has apnea. Sometimes he will stop breathing or his heart will stop beating. It is a common problem in "preemies." The monitor will sound an alarm and Nelson's parents will poke him gently or wake him so that he will start breathing again. In the past night and day, Nelson has stopped breathing unusually often.

Dr. Morgan begins explaining to Nelson's father the tests they will give Nelson -- no easy task, since Dr. Morgan speaks only a little medical Spanish. Although Juan Benitez understands some English, medical terminology is beyond him.

"We need to give a spinal tap," she says. He does not understand. She traces the line of his spine. "Espino?" she says. He nods. "What is the risk?" he asks. He agrees to the test.

Juan Benitez waits outside while his son is given a blood test and a spinal tap. Nelson is changed out of his red-and-white-striped sleep suit into a paper hospital gown. He's too small for even the infant-sized gown.

Nelson seems fine. His heartbeat is strong. And he has a fine pair of lungs. He begins to bawl as Dr. Morgan takes his blood. She grins ruefully. "I have a feeling that 20 years from now a bunch of preemies are going to come back and get me," she says.

It is possible that Nelson has spinal meningitis or a virus, she explains, which is causing more frequent apnea.

The samples are sent for analysis. It will be one to two hours before the staff will know the results. Juan continues to wait, jogging his baby gently from time to time. His wife is at home with Nelson's twin brother, the older by an hour and a half. As is common with twins, the elder is stronger.

Sean is wheeled by on a stretcher. There is no damage to his vertebrae, and, except for two missing front teeth, he seems fine. But he will stay the night just in case.

Dr. Scott Schubach, a senior surgical resident down from New Hampshire for pediatric training, checks his next patient's chart at the desk. He has just finished with a 9-month-old who swallowed a penny. The coin lodged in her throat, and she vomited her evening meal.

"This is really common," Dr. Schubach says. "I've been here for three months and seen four or five similar cases. Kids will swallow watch batteries, screws, buttons, anything." The coin is dislodged from the infant's throat and she is sent home.

One of the doctors is suddenly called away from the desk. A seven-day-old baby is coughing up blood. On a wall behind the desk, a huge board provides space for listing patients by room, doctor, admission time, treatment. It is blank. It would take a computer to follow all the cases admitted tonight -- if any staffer had time to enter them.

Debra Smith wants to know if her son will suffer loss of hearing. A doctor draws a diagram of Donnell's ear, explaining that there is no danger. He gives Donnell the prescribed antibiotic in the hospital, since the Smiths will take a cab home and do not live near an all-night pharmacy.

Nelson Benitez, the apnea victim, has been moved to the observation room. Now that he is no longer being stimulated by the tests, it is clear that his breathing and heartbeat are dangerously irregular. Six doctors hover over the 6-pound, 6-ounce infant. He is put in an oxygen tent, and soon begins to cry lustily.

"He is probably hungry," Juan Benitez explains, in Spanish. A Spanish-speaking staff member is called away frequently from other duties to translate. Juan and the staff struggle to understand each other. He says he is pleased by the amount and speed of attention Nelson is getting.

The spinal tap shows that Nelson has no meningitis. Nelson will stay in the hospital overnight for tests to determine whether he has respiratory syncytial virus, a common threat to preemies. Juan Benitez plans to take a cab home as soon as Nelson is settled. He is due at work at 8 the next morning at a Potomac restaurant, where he makes salads.

At midnight, the emergency room still swarms with activity. Some of the parents are still waiting, as urgent cases are treated and new patients needing immediate treatment arrive.

"I wouldn't train anywhere but a pediatric hospital," says Dr. Morgan. "Everything here is for the kids -- treatment, X-rays, everything. The staff here in the ER is great."