"We hope the hospital will see how valuable the workforce is," said John Reid, executive vice president of the union. "At the end of the day, we are the unseen workforce and the backbone of the hospital."

Windsor said Hopkins and other area hospitals face an uncertain financial future because of a plan adopted by the state this year that ties how hospitals are reimbursed for patient care to the state economy. The plan eliminates a system in which hospitals are paid based on the number of patients they admit and calls for more treatment in urgent-care centers, clinics and places other than hospitals.

"I think there is a lot of uncertainty in health care right now," Windsor said. "A lot of hospitals are unaware of what the future will look like for them. So it is hard to plan for many years in the future. Union contracts generally cover many years."

It is a risky time to strike because so many people are still without jobs, Drexel's Harrington said, and low-skill employees are easily replaceable. A three-day strike could be a strategy to help the union cause disruption while preserving workers' jobs.

Union members are scheduled to resume work at 6 p.m. Friday, but they could strike again.

"We're far apart — what they are offering is not fair," Reid said of the Hopkins wage proposal.

During Wednesday's strike, workers carried signs that said "More Money" and "Poverty Wages." They chanted slogans like "Gotta feed our children, gotta pay our rent, ask Johns Hopkins where the money went." Some passing vehicles honked in apparent support.

Every two weeks, Hopkins housekeeper Yolanda Kelly said, she overdrafts her bank account just to pay her bills on time.

On Wednesday, Kelly blew on a plastic whistle and hoisted a protest sign with other hospital workers.

"We made Hopkins No. 1," said Kelly, 45, who has worked for Hopkins for three years. "We did this. And they don't really care about us. And they're proving it because they're not negotiating."

Workers said it seemed unfair that employees with many years or decades of experience at Hopkins didn't make much more money than those just starting out.

Dorothy Karugu, 50, who has worked as a clinical assistant in the surgery department for 20 years, said she makes about $15 an hour.

"I feel like they're getting rich off our sweat," said Karugu, referring to Hopkins officials. "If I don't work overtime, I can't pay my bills — at least 20 hours per pay period. I'm fatigued, and it's taking a toll on my health. It's not fair that they give us merely pennies and expect us to live on that."

Baltimore Sun reporter Carrie Wells contributed to this article.