CRANSTON, R.I. — There were 12 covid-19 patients in the state's new field hospital here, and the small staff was preparing for nine more on this rainy, gloomy Monday. Just three miles away, at Kent Hospital, it was much worse.

On one of the worst days of the current covid-19 surge, the acute care facility in Warwick was nearly overrun. Patients in the emergency department were waiting two and three days for one of Kent’s 359 beds. With so many patients in so many beds for so many hours, the emergency room was functioning as another inpatient unit of the hospital that has served this community since 1951.

The best hope was to move some patients with covid-19, the disease caused by the coronavirus, to Alternate Hospital Site Cranston, the formal name of the vast field hospital that an overworked team is outfitting and operating on the fly.

“We feel like we’re racing against the clock,” said Laura V. Forman, who is co-medical director of the field hospital and head of emergency medicine at Kent.

“We’re teetering on a crisis level of care,” she added, using the term of art for a decision to begin rationing assistance among patients. “And we have to avoid that.”

With tens of thousands of covid-19 patients hospitalized during the year-end explosion of the coronavirus, health authorities are again turning to field hospitals such as this one in spots across the United States. In California, they are in huge tents. In Wisconsin, one stands at the state fairgrounds. Some cities have converted convention centers, as New York did when the first surge hit in April. Here, the facility occupies a vast two-story building that once housed a call center and the headquarters of a bank.

More commonly associated with war zones than one of the world’s most sophisticated medical systems, field hospitals are a sad symbol of how poorly the United States has handled the pandemic.

But they are also a glimpse of the future. Alternatives such as this have accelerated medicine’s understanding of how much care can be delivered at home and in other locations outside hospitals and doctor’s offices. No one expects health care to return to its pre-pandemic normal.

“We’re looking for ways to innovate quickly,” said Paari Gopalakrishnan, chief medical officer of the field hospital.

On Dec. 14, the day The Washington Post visited the Cranston facility, Rhode Island’s rate of positive coronavirus tests was an alarming 8.1 percent, and its 111.3 new cases for every 100,000 residents was among the highest in the country. Not surprisingly, 509 people were hospitalized with covid-19, nearly the largest number the tiny state has seen in a single day since the pandemic began. About 100 were in Kent Hospital.

The field hospital was built, in part, as a safety valve for times like this. The first patient arrived Nov. 30, moving into one of the beds in Pod 1 of Ward C, even as Gopalakrishnan and his staff of nearly 300 continued to outfit the 94,000-square-foot clinical area. Row after row of beds, 331 in all, are lined up in three separate wards, the “rooms” separated only by curtains.

Beyond the “hot zone,” where everyone works in full protective gear, other workers and a handful of National Guard members occupy more of the huge structure that Citizens Bank once called its headquarters. Some rooms still have rows of desks and chairs, now unused, from the facility’s former life.

Other than the police guarding its entries, the hospital could be any other low-slung building on the street, where it sits across from Town Fair Tire, Subway, a Citizens Bank branch and a credit union.

In nearby Providence, another 600-bed field hospital in the city’s convention center is accepting patients. The state constructed the hospitals in less than three weeks during its first surge in April, but did not need to open them. Now, it does.

So far, about $30.6 million has been spent, with reimbursement expected from the Federal Emergency Management Agency and the relief bill approved by Congress last week, according to a spokesman for the state Department of Administration.

Staffing is the main issue for the field hospital, operated by Care New England Health System, which owns Kent Hospital and others in the area. With uncontrolled spread of the virus in every corner of the country, the demand for nurses and other staff is higher than ever. The field hospital depends on a large contingent of travel nurses, here from other parts of the country on short-term contracts.

The field hospital has two missions: to relieve the pressure on Kent and two other hospitals by accepting recuperating patients, still coronavirus-positive but unable to go home yet; and to be prepared for more and sicker patients if the surge worsens.

On this Monday, Gopalakrishnan was sure he could handle 50 patients. Maybe more if he had to.

“If I had 100 and the same staff, it’ll be stretched,” he said. “We’ll do it. We’ll do it safely. It wouldn’t be ideal. But we’ll do it.”

The limits of this kind of medicine are plain to see. The floors are concrete, the oxygen delivered to each bedside in copper pipes exposed along makeshift walls. The hospital has no X-ray machine or CT scanner. Patients cannot be intubated here, except briefly in an emergency. There is no equipment for dialysis. For any of those services, patients would have to be moved back to Kent or another hospital.

Patient rooms have no electronic intravenous pumps. Nurses calculate medication doses using the old-fashioned method of counting the drops in the tubes that run into patients’ arms and extrapolating.

There are few computers and no electronic medical records. Doctors and nurses use paper charts. Several nurses said they prefer being unchained from the computers on wheels they use at traditional hospitals, leaving more time for contact with patients.

Metal trays designed for surgical instruments double as bedside tables. Instead of pressing call buttons for nurses, patients ring the kind of bell that hotel front desks once featured.

Initially hesitant about the field hospital, one patient said she had grown to appreciate the attention she was receiving there. Without walls, she could hear activity in the corridors. She knows help is not far away.

The woman, who lives in Batavia, N.Y., acknowledged that she embodies the warnings health authorities offered before the holiday. She and family members from other places quarantined for 14 days, then traveled to this area for Thanksgiving. More than 20 people came down with the coronavirus after the holiday gathering, possibly infected by one relative who broke quarantine briefly, she said. The only member of the group who was hospitalized, she has since been discharged. The Post is not using her name to prevent identification of her family members.

Without walls, the spot where she convalesced is part of one immense hot zone. Everyone has covid-19, so patients can congregate if they are able, without fear of infecting one another. Instead of donning and removing protective masks, gowns and other gear many times a day, nurses spend their entire 12-hour shifts in protective equipment. A negative pressure system for the entire facility blows the virus out.

The nurses prefer this.

“I don’t feel like it’s a danger to our health, because we don’t have that constant taking off the PPE and breaking the barrier and having to put it back on,” said Preston Eyerman, a traveling nurse from Arizona.

Among the staff, the sense of mission is palpable. Most have volunteered to be here, eager to contribute in a crisis and acutely aware that many providers are exhausted by a year of caregiving.

“I like that I have some skill set that is much needed right now,” said nurse Naomi Barnum, who has worked every day for a month at the field hospital or a nearby intensive care unit. “I’m choosing to do this. . . . There’s very much a need for it. It’s my own community. It’s my own neighbors I can help. It sounds overwhelming and exhausting, but for me it beats the alternative.”

“I wanted to pay it forward,” added Sabrina Geer, a New York nurse who appreciates the aid nurses from other parts of the country provided when the virus raged through her city in April.

The atmosphere is comparable to a tech start-up, said supply chain manager Brad Morisseau. There hasn’t been time for bureaucracy to ossify. Ideas are welcome. Problem-solving skills are at a premium.

Nursing officer Bill McGuire has moved a cot into an unused office and sleeps at the facility most nights.

“We’re all sort of equal opportunity, offering up ideas, collaborating, teaching each other,” said nurse Heather Wisdom, who is here from Kentucky. “We’re also learning who has what skills. If someone can’t do this or they haven’t done this for a while, well, this is the person you go to for that.”

But there was no way to plan for every contingency. When patients arrived, there were no blanket warmers. Food can be ordered from outside, but how would security and infection control be enforced? Now that older patients are being accepted, beds with guard rails had to be brought in.

“I feel like we’re constantly solving a Rubik’s Cube,” Forman said.

Originally, the field hospital planned to take less severe cases of covid-19, but as the surge played out, doctors discovered that many of those patients were being treated at home. Now, they hope to take more serious cases, including older, less ambulatory people. The hospital also has begun to offer infusions of remdesivir and monoclonal antibodies, therapies for covid-19, to outpatients.

With Christmas here, the field hospital staff expects another surge in a few weeks, from the travel that already has begun and the unmasked shoppers Forman has seen at a nearby mall.

“Every day, we’ve got to be adaptable,” Gopalakrishnan said. “Every day it’s going to change. The mind-set here is nothing is going to shake us.”