Hospital emergency rooms around the country are becoming critically overcrowded - to the point where they are suffering an emergency of their own.

This is not just a case of knife-and-gun club overload in the urban cores, according to an article in the current issue of Esquire, but also because many people during the past 20 years have replaced their family doctor with the hospital emergency entrance.For some, it is the only care they can afford - one estimate finds 37 million Americans with no health insurance - and federal law forbids emergency departments from turning them away. Others think "health care" means high-tech remedies for every ailment.

Some hospitals claim they lose so much money on non-paying patients that they plan to downgrade or abandon their emergency service.

Most hospitals today contract with emergency specialists, or keep them on staff, to run their ERs. Emergency medicine gained recognition as the newest of the 23 medical specialties in 1979, 11 years after a group of doctors formed the American College of Emergency Physicians in 1968.

A recent ACEP survey found emergency departments in 41 states reporting overcrowding that can cause serious delays in treatment.

"Even hospitals with no knife-and-gun club problems have overcrowding," said Dr. John Johnson, president of ACEP. He directs emergency services at Porter Memorial, a 350-bed hospital in Valparaiso, Ind., 45 miles from Chicago.

"We don't have a crack problem. The entire county probably has no more than 10 AIDS patients. In 33,000 emergency visits a year, we get only about a thousand trauma (severe injury) cases. Yet at one point this January we had 17 emergency patients waiting for beds for several days."

To improve on your chances of finding the right emergency room, here are some suggestions distilled from comments by Johnson, Dr. Alan Gelb, emergency department chief at San Francisco General with 84,000 emergency cases a year, and Patrick Donohew of the National EMS Clearing House in Lexington, Ky.

Board certification of ER doctors is not yet as important in emergency medicine as in older specialties. The ACEP held its first board exams in 1980; 8,332 of the 27,000 emergency physicians in the United States have passed.

"If a physician has been practicing emergency medicine full time for three to five years, you've probably got yourself a good doctor," Johnson said.

Find out if the nurses actively "triage" incoming patients by separating urgent cases from those that can wait.

"If you're not face-to-face from the moment you appear with somebody who can tell how sick you are," Johnson said, "you're not in an effective emergency department."

An emergency room should have a specialty call roster in surgery, both trauma and neuro-; orthopedics; pediatrics; obstetrics, and acute medical - mainly cardiology and chest.

Find out the waiting time in the ER if you have to be admitted. The wait for cardiac arrest should be zero; for a sprained toe at a busy time, it could be hours.

Gelb said in his city, with code three calls (lights and sirens) both a fire rescue truck and an ambulance respond. His hospital's paramedic response time is about nine minutes, while fire response time is three to four minutes. "Though firefighters can't do everything paramedics can," he said, "they can start CPR, defibrillate and perform other immediate tasks. You want that first responder in about three minutes. If your heart stops and you don't get it then, you're dead."