Negotiators for Washington Hospital Center and about 1,100 striking nurses offered little hope yesterday for an end to the work stoppage soon, and nurses marked four weeks on strike with a rally.

No new negotiating sessions are scheduled, and the two sides are far apart on a wage package and rules governing how often the hospital can schedule a nurse to remain on the job at the end of a regular shift.

The union has cast its strike more as an expression of principled concern over deteriorating patient care than as a battle for better pay and working conditions.

"The nurses are strong and courageous," said Evelyn Sommers, executive director of the D.C. Nurses Association. "They plan to stay out. They are patient [care] advocates, and that's what they're going to do."

Contract talks have dragged on under the supervision of a federal mediator, but the situation has not remained static. So far, about 150 nurses in the union have crossed the picket line, and an additional 25 to 50 have expressed interest in doing so, hospital President Michael H. Covert said yesterday.

Sommers disputed those figures, saying the number of union members who returned to work is less than 90. "We still have 90 percent-plus out on strike--that's really the important message," she said.

Perhaps more importantly, the hospital's wage offer has been steadily shrinking as the cost of expensive replacement nurses mounts. Covert said he is delighted with the performance of more than 600 temporary nurses imported from across the nation by Denver strikebreaker U.S. Nursing Corp.

However, the service is expensive, Covert said. "You could be talking about a maximum of $500,000 a week in losses," he said. "In terms of the reserves of the institution, that's not what we want to do. It's not just salaries, but housing and travel. But we can go as long as we have to go."

The hospital has withdrawn its proposal of a 16.5 percent wage increase over three years and now is proposing 13 percent over the same period.

"At some point, the employer has to make the call that the expenses during a strike affect funds available for other operations," said the hospital's lead negotiator and labor counsel, Victoria Houck. "Four weeks into the strike, we concluded we had to make that decision."

Covert said the hospital, the region's largest medical facility, has continued operating at full steam. "We had a record month last month," he said. "Nothing fell off, and that may have come as a surprise to a number of people."

The 907-bed hospital counted 788 patients yesterday morning, and recently the average weekday census has ranged from 750 to 790, he said.

Among the key remaining issues are mandatory overtime and night work. The hospital has offered to limit forced overtime for each nurse in most departments to one added eight-hour shift every six weeks. In some specialized departments, that would be higher.

Hospital officials also want to be able to rotate operating room nurses through a full week on the evening shift to accommodate an increase in elective surgery that doctors have been performing late in the day.

At union meetings nurses have said they want to hold out for more than that, Sommers said.

"We certainly have very lively discussions," she said. "Nurses are smart people and looking at all the options--but they have not discussed giving up. There is enormous unanimity about the issues they will stay out on."

Just before joining the spirited rally and march last night, a veteran Washington Hospital Center nurse, Joanne Lower, 53, of Bowie, said she should not have to change her schedule because of the hospital's persistent staffing problems.

"When you're working permanent day shift and you have to change to an evening shift, it disrupts your family and social life," she said.

In the meantime, nurses like Lisa McGuire, 44, of La Plata, say they won't consider crossing the line. "The nurses that are out realize that if we stick together things are bound to get better," McGuire said.