Michael Culhane had messed up in an EMT practice exercise, and his trainer was letting him know it. There is a cadence and order to the questions that medics ask on emergency scenes, and the 47-year-old firefighter had scrambled them.

"What are you doing?!" the trainer exclaimed.

The criticism was harsh and true, and Culhane was happy to hear it. After nine months in COVID-19 recovery — after receiving overwhelming support to sit up, then stand, then walk again — he wasn't getting sympathy points here.

If Culhane was going to complete the firefighter training he started before COVID-19 hit him last August, there would be no free passes.

"I don't want that," he said. "I don't want special treatment."

Culhane shared his recovery story this week after returning to HCMC in Minneapolis to thank the caregivers who helped save his life — people he didn't really recognize because he was in a sedated coma during his three-month hospitalization.

The U.S. Centers for Disease Control and Prevention last week estimated that 1 in 5 middle-aged adults and 1 in 4 seniors have at least one lingering condition after COVID-19. But who recovers, and by how much and how fast, remains a mystery.

Culhane might never know why he had such a bad illness or good recovery, but he said the experience can offer hope to others amid severe COVID-19 journeys.

"It's going to hurt to get up and go try to walk and then go try to walk a half mile and then walk a mile," Culhane said. "That stuff sucks, but you can get there."

The St. Anthony village firefighter is among the inspirations who have emerged in Minnesota during the pandemic. Ben O'Donnell recovered from one of Minnesota's first severe COVID-19 cases in spring 2020 and was featured on ESPN this month for finishing an Ironman triathlon. Dr. Nyan Pyae was hospitalized more than 100 days with COVID-19, but the kidney specialist returned to practice — and was one of Culhane's doctors at HCMC.

Like many with severe COVID-19, Culhane thought he was getting better after his infection before he got worse. His skin looked gray and his lips purple when his family called for an ambulance. Medics measured his blood oxygen below 60. It should have been above 90.

Culhane was placed on a ventilator at HCMC. His oxygen levels would improve when rolled onto his stomach but plummet when returned to his back. He was recommended for extracorporeal membrane oxygenation, or ECMO, a bypass machine that filters blood when the lungs can't keep pace. The death rate of COVID-19 patients on ECMO is 47%, according to an international registry, but Culhane was running out of options.

"He was frankly lucky that his body responded the way it did," said Dr. Matthew Prekker, an HCMC critical care specialist.

The months that followed were dark and disconnected in Culhane's mind, but long and vivid for friends and family.

Longtime partner Erin Kintop had to OK the ECMO by phone, because she was recovering from COVID-19 and not allowed to visit. She spent the first summer nights of Culhane's hospitalization on their porch, staring into the evening and hoping the phone wouldn't ring with bad news. A burned-out garden light turned back on, and she took it as a sign.

"It indicated to me that Mike was still alive," she said.

St. Anthony Fire Chief Mark Sitarz worried right away about Culhane — a friend and neighbor who stunned him by applying at midlife to join his department and train with men half his age. After the 911 call, the chief visited Kintop and Culhane's parents and prepared them for the challenges ahead.

Sitarz visited Culhane's hospital room but talked to him from outside the doorway — wanting to save two permitted daily visits inside for others.

"We've got your back," Sitarz recalled telling him. "You've got to pull through."

Culhane was unvaccinated, which increased the odds of a severe illness. A study of military veterans last week confirmed that vaccine reduced the rate of COVID-19 hospitalization and death, although it offered less-than-hoped protection against post-COVID symptoms.

COVID-19 itself is a complication beyond other causes of respiratory failure. Prekker presented study results this month that compared ECMO outcomes of eight COVID and six non-COVID survivors. While a small sample size, the comparison showed the COVID-19 patients spent 18 more days on average in rehabilitation facilities and were half as likely to return to work within two years.

Culhane was removed from ECMO after 37 days but didn't regain consciousness as quickly as hoped. Imaging scans showed tissue damage in his brain, and doctors weren't sure if he would emerge with his thinking skills intact.

"For every day he was down, they said it would take three days to recover, and you start doing the math," Kintop said.

Turns out, Culhane just needed time. The first sign of cognition came to Kintop when she was sitting with Culhane and watching a TV cooking show. Culhane smiled and mouthed the word, "chicken," which is what was on the screen. More hopeful signs emerged and he was moved in late October to the Regency long-term care hospital in Golden Valley.

The first attempt at sitting up shot pain through his body. Culhane said he felt like a bobble-head with neither the neck strength to support his head nor the core strength to prop himself for even a few seconds.

Culhane started to dream small. Maybe he could use a walker to get to the fire station and visit the crew. He was moved to the Aurora rehabilitation facility in Edina to rebuild strength. On Christmas Eve, he managed to travel 30 feet with a walker.

"I was so excited," he said.

The dreams got a little bigger for the father of four children ages 17-24, keeping him motivated when painful exercises produced imperceptible progress. Maybe he could attend his youngest son's basketball games in winter and high school graduation in spring. He had switched careers from auto sales to insurance and was eager to get back to his agency.

"It's not like all of a sudden I would have these huge gains," Culhane said. "I was getting better, but it's those little things you don't notice."

By his discharge home in January, his lungs were still below capacity, but his goal was to be a firefighter again. He attended the swearing-in ceremony of his class of trainees, which was motivating.

Fast forward to last weekend, when Culhane wore an air tank and mask for a training exercise and breathed normally and without anxiety. He stood for four hours performing water pumping operations and working with handlines. He thought back to when he couldn't even stand for four minutes.

Culhane isn't cleared for full duty, needing to complete his EMT training and gain a doctor's clearance letter. The latest goal is to walk that letter to the chief's desk this summer.

"I made a commitment to myself, to the community, to my fire chief and to the department," Culhane said, "and I will see it out."