More than six years after ground was broken, the new $58 million Children's Hospital National Medical Center - a dramatic, silver-windowed structure on Michigan Avenue, NW - is only months away from receiving its first patient.

The change could scarcely be more dramatic - from cramped, crowded corridors and rooms where patients and parents are shoe-horned in, to spacious, carpeted halls; from dark, cheerless spaces where the depression of a hospieal becomes almost irresistible to brightly-lit, color-splashed rooms and halls that seem almost boisterously gay.

Children's Hospital is a nationally renowned nonprofit institution. In moving from 13th and W Streets NW to Michigan Avenue NW, Children's will beentering a structure worthy of its reputation.

What is not clear, and what may not be clear for years, is whether the $58 million cost of the new hospital was necessary to bring the highest quality health care to the children treated there, or whether the building is a lavishly designed, expensively built glass castle with unnecessary frills and design features.

What is also not clear is whether the new building, designed in part to overcome the resistance of local pediatricians and parents to using the old facility, will result in a more economic use of hospital space in the metropolitan area.

Comparative statistics about the new and old hospital give an idea of the dramaic change about to occur when the new structure opens some time in late May.

The new hospital will have rougly twice the space as the old, almost twice the number of operating rooms, 2 1/2 times the number of parking spaces, twice the number of intensive care beds and enough beds so that every child can have a parent stay next to him or her in the hospital. The new intensive care unit, according to one doctor, will be not only twice as big as the old, but "six hundred times better."

In the old building, and emergency room patient who must be operated on has to be transported down a public corridor, and up a public elevator, to on of the six operating rooms.

The new hospital, arranged to save time if not space, has the 11 operating rooms located one floor up and directly above the emergency room and the intensive care unit directly over the operating rooms - all served by special elevators used exclusively for transporting patients and staff between those areas.

Within the intensive care unit, a satellite pharmacy will provide drugs immediately. A ceiling mounted x-ray machine will be able to cover six beds, and developed x-rays can be shown over a television screen so that they can be discussed immediately after development.

Records, samples, specimens and other materials will be transported on a $500,000 "telelift" system that hospital officials say will save time and money by reducing the number of messengers needed to carry the materials.

Children's, which is affiliated with the George Washington University medical school, will continue research being done in its present facility as well as expanding its program. The nursery, where seriously ill newborn and older infants are treated, will be expanded from 30 to 36 beds. A new eight-bed pyschiatric unit will be added so that mentally disturbed children can be treated in Children's rather than being referred to other institutions.

A new department of pulmonary medicine will be opened to study and treat a whole range of diseases associated with the lungs.

A short-ray, "in and out" surgery unit will be added to reduce the hospitalization period for patients who can be released quickly.

The hospital's design is unconventional and controversial. Where most buildings have only one outer wall, Children's has two - the glass exterior that gives the structure its distinctive appearance and an inner wall. Between the two walls is a space of some two to five feet.

The hospital's designers say that the double-wall constuction, comboned with the slanted-glass construction will conserve energy and make it possible to maintain constant temperatures in the hospital more easily.

Between each floor of the hospital is a service or interstitial floor, designed to house all pipes, dugs, ventilation equipment, wiring and other service equipment. The hospital's designers maintain that keeping the "use" floors free of this mechanical equipment will ultimately save money and keep disruption of hospital services to a minimum.

One skeptic who supported the concept of a new Children's Hospital but doubts that it needs to have been so expensive is Grady R. Smith, chief of the Department of Health, Education and Welfare's hospital architechtural, engineering, design and equipment branch. "I think you pay for space," Smith said in a telephone interview. The costs of building Children's, Smith said, have been "just a little on the high side, but not outrageously high."

The double-wall construction and the extra floors between patient floors are two obvious examples of space used lavishly. "Whether the benefit is there or not is debatable," Smith said of the interstitial floor design.

Smith also believes that "it's going to be very interesting to see if that building is going to be as energy efficient as the original designers said it would be . . . That's one of the things we'll be interested to see - who was right."

But Smith, who said at one point he thought the structure threatened to become "a castle (built) without any regard to cost or life safety," now believes it to be safe and slightly expensive. "I don't have any great problems," he said. "I probably could have done it for less; but I don't think it was that much more."

A brochure published by the hospital, explaining its design and answering questions about it, states that the cost of the structure is about $53 a square foot.

This figure, based on construction costs of $58 million, includes the floor area of the hospital, the 1,000 car garage and 10 per cent of the area of interstitial spaces.

In the hospital and garage are figured separately, however, the hospital cost is about $86.66 a square foot - including the hospital area, 10 per cent of the interstitial space and echanical space on the roof - while the garage cost is about $16.28 a square foot.

Some of the space requirements inside the hospital are greater than normal. Providing a parent bed next to virtually very patient bed inceases the space needed, for example.

"That's our whole concept of what is needed for the care of a child in a hospital," said Harold Kranz Jr., director of public relations for Children's. "Otherwise, we'd be a general hospital with a pediatric ward. It's not a luxury. It's not something that we think is nice for the parent. We think it's necessary for the care of the child."

Although Children's takes patients from birth through 18 years, more than half of the children in the hospital are under two. Kranz said that with the new facility's room for parents, "we expect and will encourage one of the parents to stay the majority of the time that the child is there."

The substantial parking garage under the hospital is another feature that hospital officials say is essential. Lack of parking has been a deterrent to greater use of the old facility, according to hospital officials.

Unable to find space in the public lot next to the hospital, which accommodates a maximum of 70 cars, and unwilling to walk at night three or four blocks through one of the city's highest crime areas, parents have turned to other hospitals in the area to care for all but the most serious of their children's health problems.

Doctors, reluctant to send children to a facility that parents are hesitant to visit and often finding it difficult to schedule time in the operating room, also have turned to other hospitals.

One result has been a proliferation of pediatric hospital beds in the Washington metropolitan area. Besides the 220 beds in the present Children's facility, there are about 400 more pediatric beds in the area distributed between 13 other hospitals.

Children's had an occupancy rate of about 65 per cent last year, according to data collected by the Hospital Council for the National Capital Area. The occupancy rate for all hospitals was only about 59 per cent. Hospital authorities estimate that a hospital must have an occupancy rate of about 85 per cent to operate efficiently.

Initially, Children's will have only about 220 beds in its new hospital, with the capacity for 260 if demand warrants the increase.

Whether demand increases depends to a substantial degree on the referral practices of local pediatricians.

Dr. Beale H. Ong, chairman of the District of Columbia chapter of the Academy of Pediatrics, said the District's medical society "absolutely" will encourage local pediatricians to use the new hospital. "The physical plant is more attractive and the location is more secure," Ong said in a telephone interview.

Ton increase its occupancy rate, Children's must attract not only the but the routine illnesses and problems most complicated and serious cases but complicated and serious cases, but the routine illnesses and problems that require hospitalization. "I think more and more we're going to be taking care of most of the pediatric cases.

At the same time, Ong said, Children's will maintain the relationship it has with the inner-city population it serves now. "We'll still take care of and work with the inner-city population," he said. "They're still going to come. That won't change. They'll get there."