For more than 150 years, St. Vincent’s Hospital Manhattan has been a beacon in Greenwich Village, serving poets, writers, artists, winos, the poor and the working-class, and gay people.

It has treated victims of calamities: the cholera epidemic of 1849, the sinking of the Titanic in 1912, the 9/11 attack and, just last year, the Hudson River landing of US Airways Flight 1549. The poet Edna St. Vincent Millay got her middle name from the hospital, where her uncle’s life was saved in 1892 after he was accidentally locked in the hold of a ship for several days without food or water.

But today the hospital is struggling, and last week, in what could mean the death knell of the last Roman Catholic general hospital in New York City, a chain of hospitals proposed to take over St. Vincent’s, shut down its inpatient beds and most of its emergency room services, and convert it into an outpatient center tied to hospitals uptown and on the East Side.

Gov. David A. Paterson’s office said on Tuesday the state was extending a $6 million emergency loan to help St. Vincent’s meet its payroll, an indication of how dire its finances had become.

How St. Vincent’s went from a cherished neighborhood institution to one threatened with extinction is a chronicle of increasingly troubled management whose problems were made worse by the economics of the health care industry, changes in the fabric of a historic neighborhood and the low profit potential in religious work.

It was once part of the Roman Catholic Church’s social and political network in New York City, a cradle-to-grave embrace of parishioners who were born in Catholic hospitals, educated in parochial schools, married in the church and given last rites by a priest.

Last week, a day after the announcement of the proposed takeover, members of the Sisters of Charity, the Catholic order of nuns that founded the hospital in 1849, gathered for a noon Mass at St. Vincent’s second-floor chapel and vowed to fight. “We are not going away,” said Sister Jane Iannucelli, vice chairwoman of the hospital board, standing in the light of stained glass windows.

“One of the things that’s so crucial to the Sisters of Charity is serving the poor,” she said.

It was that very calling, some industry executives suggested, that may have helped make the hospital obsolete.

“Helping the poor is indeed the mission and the cause célèbre,” said Kenneth E. Raske, president of the Greater New York Hospitals Association, a trade group. “Therein lies the dilemma.”

Other hospitals emphasize high-tech care and rush to invest in the fancy equipment and celebrity doctors that attract patients with the means to pay for them; St. Vincent’s sticks to its motto of “compassionate care,” rooted in its origins as a place that trained nurses and that was under the auspices of nuns.

As the Village changed, becoming home to more middle-class families, by many accounts St. Vincent’s failed to change with it. In 2007, several years after an ill-fated merger with other Catholic hospitals, St. Vincent’s management proposed selling off its maze of outdated buildings around Seventh Avenue and 12th Street to build a state-of-the-art high-rise building across the street, to be designed by Pei Cobb Freed & Partners Architects, famous for cutting-edge projects like the glass pyramid expansion of the Louvre museum in Paris and the John Hancock Tower in Boston.

But some said it was too late. In an indication of how St. Vincent’s reputation had fallen in the neighborhood, during a fierce debate over whether to demolish a low-rise Modernist building to make way for the new hospital, the actors Susan Sarandon and Tim Robbins suggested that St. Vincent’s no longer served the neighborhood well.

“I would not want to bring my children there,” Ms. Sarandon declared at a landmarks preservation hearing.