When a ventilator wasn’t enough, this coronavirus patient went on ECMO. It was not a sure thing.

The morning after Daniel Bisset Jr. went on a ventilator, doctors could tell it was not getting the job done.

His lungs, inflamed and filled with fluid by the coronavirus, could not extract enough oxygen from the tube nurses had pushed down his throat. His 48-year-old body was in danger of shutting down.

So staff at the Geisinger health system tried a high-tech measure of last resort for Bisset, a sheet-metal worker from Clarks Summit, Pa. They connected him to an external lung.

Technically called extracorporeal membrane oxygenation — ECMO — that procedure has now been performed on more than 800 COVID-19 patients worldwide.

It is far from a sure thing. Among 276 COVID-19 patients discharged from hospitals so far after undergoing ECMO, 132 — under half — survived, according to a registry maintained by an international consortium of health care institutions. Hundreds more remain in the hospital.

ECMO (ECK-moh) is not a treatment for inflamed, fluid-filled lungs. Instead, it buys time so nurses and doctors can address those issues, said Deepak Singh, director of cardiothoracic surgery for Geisinger’s Northeast Pennsylvania region.

“It’s not fixing the lungs,” Singh said. “It gives you an ability to keep the patient alive and to allow his body to recover.”

For Bisset, it turned out to be the right call. But before he emerged from a medically induced coma, the coronavirus would claim another family member instead.

Bisset thinks he picked up the virus March 7 at a beer festival in Brooklyn. He started to feel sick three days later, and by March 16 he could barely breathe.

His wife, Shannon, took him to Geisinger Community Medical Center in Scranton.

For patients on a ventilator, blood oxygen levels are expressed as a ratio called P/F — a measure of how well the body is absorbing the essential gas.

If a patient is getting pure oxygen, a ratio below 200 is considered “moderate” respiratory distress. Below 100 is severe. After a night on the ventilator, Bisset was stuck in the low 80s.

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At 6 feet tall, Bisset was pushing 300 pounds and also had elevated blood pressure — two risk factors that set grim odds.

Geisinger critical care physician John Sobuto urged the use of ECMO. He told Shannon Bisset the procedure could cause blood clots, among other risks, but he felt it would give her husband his best chance. She agreed.

But that meant the patient, once connected to the machine, would travel 80 miles by ambulance to Geisinger’s flagship hospital in Danville, where a team of specialists would oversee his care.

His wife, awaiting test results to see if she had the virus, had to isolate at home.

The concept behind ECMO is straightforward. Take unoxygenated “blue” blood out of a vein in the patient’s groin, pump it through the machine to add oxygen, and put it back in through a vein in the patient’s neck. (The machines also are used for patients recovering from heart surgery, but are attached in a different way.)

Typically, an ECMO patient also remains connected to a ventilator, with that machine on a low “rest” setting so the lungs do not shut down.

ECMO machines have been around for decades, and patients’ odds have improved with better pump design. Still, there are risks of clotting, bleeding, strokes, and infection, and doctors have debated whether it is the best course of action for patients with acute respiratory distress.

A French study, published in 2018 in the New England Journal of Medicine, found that such patients fared no worse on ECMO than those on a ventilator alone. In both groups of patients, more than half survived.

But with the coronavirus, early reports from China were that most patients on ECMO did not make it.

The emerging consensus is that older, frail COVID-19 patients are not good candidates for ECMO, said Jack Gutsche, co-director of the lung rescue program at Penn Presbyterian Medical Center.

“They need to have some good reserve,” he said.

Gerard J. Criner, director of the lung center at Temple University Hospital, agreed. The first option is supplementing oxygen with noninvasive means, and placing the patient in a prone position to improve lung function. If that fails, try the ventilator.

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But in five COVID-19 cases so far at Temple, those measures were not enough, and patients were placed on ECMO. At Penn Presbyterian, Gutsche and his colleagues have placed 15 such patients on ECMO.

At both hospitals, some of the patients remain in the hospital. But so far, most who have been discharged have survived. The recovery is grueling.

“In my 40 years [in medicine], I’ve never seen anything that can cause people to get this sick so acutely and so profoundly, not only in the lungs but in other organs,” Criner said.

Since his wife was isolating at home near Scranton, Daniel Bisset’s sister, Lisa Harvey, who lives on the other side of Danville in Centre Hall, Centre County, stepped in as the on-scene patient advocate.

A special-education supervisor for the Keystone Central School District, she came to the hospital day after day. The first week, her brother was in an intensive care unit with a glass wall, so she could see him lying in bed.

He was heavily sedated and could not hear her. Or could he? She spoke words of encouragement through a speaker system, and held up her phone so that Shannon, calling from 80 miles away, could do the same.

“Hey, we’re here,” they’d tell him. “You’ll get through this.”

They heard nothing in response but the whirring of the ventilator and ECMO machine. Later, he moved to a room with no glass wall, so Harvey spoke to her brother via iPad.

Meanwhile, the virus had spread to others in the family.

Before Bisset went to the first hospital in Scranton, his father, Daniel Sr., 75, had come to visit, over the son’s objections. The younger Bisset had not yet tested positive, but worried he had COVID-19.

Within days, his father got sick, then passed it on to his mother, Josephine. Both were hospitalized — while his wife, Shannon, tested positive yet experienced no symptoms.

Daniel Bisset Sr. went to Wilkes-Barre General Hospital. Too sick for ECMO, he died March 26.

Josephine Bisset, 73, had more moderate symptoms, and did not need a ventilator. She was treated at the same hospital as her son, Geisinger Medical Center, and sent home.

Their son, hooked up to his machines and sedated, was unaware.

Hospitals have to make the call on ECMO judiciously. In addition to the risks, it requires staff beyond the team running the ventilator. A specialist called a perfusionist must monitor the ECMO machine round the clock. Nurses with special training are involved. The cost can run well into the hundreds of thousands of dollars, according to FAIR Health, a nonprofit that tracks health-care expenses.

Though it has facilities across Pennsylvania, Geisinger brings all ECMO patients to the flagship location in Danville so the trained team can hone its skills.

Bisset spent 10 days on ECMO, and started to improve. His lungs seemed to be getting more “compliant” — more able to expand with each mechanical push from the ventilator. They became better at absorbing oxygen.

He came off the ECMO machine, and eventually nurses also could dial down the level of oxygen he got through the ventilator, said Michael Friscia, a cardiothoracic surgeon at Geisinger.

“It’s kind of like watching the speedometer in your car as you’re going up and down hill, and applying gas accordingly,” Friscia said.

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Bisset’s sister maintained her vigil.

The hospital took care of her, too. Staffers brought Harvey home-cooked meals. A psychologist checked on her. Any time a nurse or doctor came by, she peppered them with questions.

“I want an honorary medical degree,” she told them.

Her brother was discharged April 9, after more than three weeks in the hospital. He moved to a rehab facility, starting to regain strength as he processed the news of his father’s death. His muscles were weak. He suffered tremors.

He came home on April 18 to a dinner of crab legs, fries, and coleslaw, still having trouble lifting the fork to his mouth.

But weeks after being disconnected from an external “lung,” his own were now back on the job.