In February 2015, Justin Smith was found face down in minus-4 degree weather. Doctors initially thought he was dead, but it turned out being frozen solid actually saved his life. (Lehigh Valley Health Network)

Don Smith saw the boots first, just the toes, peeking out from a drift of snow along the side of the empty road.

He brought his car to a stop, clambered out into the early-morning chill and peered through the half-light, searching for a sign of his son.

“I looked over and there was Justin laying there,” Smith recalled Monday to Pennsylvania TV station WNEP. His voice was tight at the memory of it. “He was blue. His face — he was lifeless. I checked for a pulse. I checked for a heartbeat. There was nothing.”

The 25-year-old had been lying in the cold for nearly 12 hours. It was 5 degrees below zero and snowing.

When emergency personnel arrived, they couldn’t find signs of life either. Someone draped a white sheet over Justin Smith’s lifeless body. A coroner was called, and the state police started work on a death investigation. Meanwhile, a despondent Don phoned Justin’s mother to give her the unimaginable news. Their son was gone.

Except, he wasn’t. Not according to Gerald Coleman, the emergency department physician on duty at the Lehigh Valley Hospital early on the morning of Feb. 21.

“My clinical thought is very simple: You have to be warm to be dead,” Coleman told the Hazelton, Pa. Standard-Speaker.

Coleman ordered paramedics to start performing CPR on a man who had no pulse, no blood pressure and by all appearances had taken his last breath half a day before. And almost a year later, on Monday, Justin Smith held a new conference to thank him.

Smith’s improbable survival is a story from the cutting edge of emergency medicine and, indeed, the edge of life itself. Thanks to new technology and an evolving understanding of what it means to be dead, doctors are increasingly able to bring “frozen” people back from the brink. And they’re starting to take advantage of the same mechanisms that allow the body to withstand seemingly lethal cold to save a whole host of other patients — victims of gunshots, heart attacks and spinal injuries and premature babies on the verge of brain damage who might otherwise be considered beyond rescue.

[When are you dead? It may depend on which hospital makes the call.]

The secret that saved Smith — and countless others — lies in the way the body slows down as it gets colder. According to Outside, metabolism slows by about 5 or 7 percent for every one-degree-Celsius (1.8 degrees Fahrenheit) drop in body temperature. At 95 degrees Fahrenheit, just 3.6 below normal, a person will begin to shiver uncontrollably. At 90, their lips will turn blue and their speech will slur. At 82 degrees, they’ll lose consciousness. By the time their temperature plunges into the 60s, their heart will stop beating altogether.

It’s an alarming course of events, but in some cases, such as Smith’s, it can save a person’s life. When a person’s body chills at the right rate, the associated slowing of metabolic processes will protect them from the other effects of exposure. Their lethargic cells don’t require as much oxygen, so the fact that their heart has slowed and their breathing stopped is dangerous rather than deadly. These people hang virtually in a state of suspended animation, seeming dead by all the standard measures but not irreversibly gone.

If the patient is discovered before the heart stops, and their doctor knows to immediately begin CPR, as Coleman did, they have a decent chance of making it.

Smith of McAdoo, Pa., had been walking home from an evening out with friends about 9:30 p.m. on Feb. 20 when something happened — he thinks that he tripped — and he fell into the snow.

He wasn’t discovered until 12 hours later. His body temperature was under 20 degrees Celsius (68 degrees Fahrenheit).

“All signs lead us to believe that he has been dead for a considerable amount of time,” a paramedic had said in a phone call to the hospital, according to the Standard-Speaker.

But Coleman ordered them to start CPR anyway, acting on an ICU truism: “You’re not dead until you’re warm and dead.”

“Something inside me just said, ‘I need to give this person a chance,’” Coleman told the Standard-Speaker. “This is probably going to be a futile effort,” he recalled telling the paramedic. “But I think we need to do our best for him. Okay?”

So they did their best. For two hours, emergency staff pumped Smith’s chest and puffed breaths into his open mouth until he could be flown — through a dire snowstorm — to another hospital branch in Allentown, Pa., according to WNEP.

Once there, doctors pumped Smith full of warm, oxygenated blood. Early that evening, his heart began to beat on its own.

No one was sure, though, how Smith’s brain might have been affected by the prolonged period without oxygen. Conventional medical wisdom says that the human brain can withstand just four minutes without oxygen before cells begin to die. But Smith’s case was anything but conventional.

When he awoke from his coma two weeks later, he was disoriented and weak. But his brain was unharmed. In the end, the night in the snow cost Smith his toes and both pinkies (all of which were amputated because of frostbite) but, incredibly, not his life.

Smith was released from the hospital in March and returned home May 1. He is now enrolled at Penn State University and is finishing up his degree in psychology.

“I consider myself a miracle,” he said in an interview with the Standard-Speaker on Monday.

Coleman told the newspaper that Smith is the coldest person known to have survived exposure-related hypothermia.

“We may have witnessed a game-changer in modern medicine — medicine moves forward in extraordinary cases,” he said. “His survival is a paradigm change in how we resuscitate and how we treat people that suffer from hypothermia.”

That change is already in the works. There are countless headlines and a growing body of research about techniques that help bring nearly frozen people back from the brink.

“We’ve learned that there really is no temperature so low that you shouldn’t try to save someone,” says University of Manitoba thermophysiologist Gordon Giesbrecht, informally known among hypothermia scholars as “Professor Popsicle,” told Outside.

A 2012 review article in the New England Journal of Medicine found that 50 percent of hypothermia patients who were treated with extracorporeal membrane oxygenation (ECMO) — the treatment used to save Smith’s life — recovered, even if they had been in cardiac arrest for an extended period of time. If those patients became hypothermic before their oxygen levels dropped too low, they could even escape most long-term damage.

Still, the authors note, there’s a surprising lack of standardization at hospitals when it comes to treating hypothermia. Not all facilities have access to ECMO machines, and not all doctors are even aware of the treatment. The truism “you’re not dead until you’re warm and dead” still isn’t practiced everywhere.

But medicine moves fast. Even as hospitals work to adopt new ways of treating hypothermia patients, lessons from those same patients are already being applied in a number of other areas. If extreme cold can keep a person’s organs alive even as they lie frozen in the snow, the reasoning goes, then why can’t it be used to preserve the organs of people who wound up in the emergency room?

It can, maybe.

At the University of Pittsburgh Medical Center, the New Scientist reported in 2014, surgeons are experimenting with pumping a saline solution into the arteries of critical patients suffering from gunshot and knife wounds to bring down their body temperatures.

“We are suspending life, but we don’t like to call it suspended animation because it sounds like science fiction,” said Samuel Tisherman, the surgeon at the hospital who is leading the trial. “So we call it emergency preservation and resuscitation.”

The procedure buys more time to treat the patient’s injuries. After doctors have stanched the flow of blood and repaired the damage, they can gradually rewarm their patient by returning regular blood back into their veins. Theoretically, it would work not just in gunshot victims, but in people suffering from a whole host of other problems that stop or interrupt blood flow to their brains.

The idea of chilling a person to save them is not entirely new — as early as the 1960s, surgeons in Siberia were known to put babies in snow banks before operations, according to the New York Times. And doctors have utilized therapeutic hypothermia while treating pediatric heart patients for a while now.

But the idea of swiftly replacing a patient’s blood with salt water — cooling and effectively “killing them” to save them — is still somewhat radical. It was first demonstrated by a surgeon at the University of Arizona at Tucson, Peter Rhee, and his colleagues during trials on pigs in 2000.

“After we did those experiments, the definition of ‘dead’ changed,” Rhee told the New Scientist. “Every day at work I declare people dead. They have no signs of life, no heartbeat, no brain activity. I sign a piece of paper knowing in my heart that they are not actually dead. I could, right then and there, suspend them. But I have to put them in a body bag. It’s frustrating to know there’s a solution.”

Currently, the technique is only being practiced in human trials at the University of Pittsburgh and the University of Maryland School of Medicine (where Tisherman is a professor). And it’s not without controversy. For one thing, doctors can’t get consent from patients before they try the as-yet unproven therapy, since it’s only used in emergency situations. For another, a study sponsored by the National Heart, Lung and Blood Institute that used a salt solution in trauma patients without their consent was shut down in 2009 because patients seemed to die more quickly, without offering much health benefit, according to the Baltimore Sun.

On the other hand, it’s assumed that most patients who wind up in the E.R. would opt for an experimental procedure when the alternative is almost-certain death. And researchers from a number of institutions told the New York Times in 2014 that they’ve perfected the procedure in studies with pigs and dogs. About 90 percent of animals survived in most recent trials, the Times reported.

Tisherman has not published the results of his trial yet, but lives are already being saved using a “hypothermia treatment.” A procedure that lowers body temperature by about 6 degrees Celsius is now the standard of care for premature infants and babies who have suffered brain trauma, the Wall Street Journal reported in 2013. By placing infants on a blanket filled with a cool liquid until their temperature falls and their heart rate slows, doctors gain about 72 hours to treat a health crisis while protecting the brain from harm.

The procedure may have saved young Mariela Lopez, who was born weighing just more than 5 pounds and not breathing one day in 2013.

The tiny girl was rushed to the Benioff Children’s Hospital at University of California at San Francisco for the cooling treatment while doctors treated her injury. A few days later, she was slowly rewarmed, wrapped in a blanket and returned to her mother’s embrace.

“Sometimes we look at it like a rebirth,” Susan Peloquin, a UCSF neonatal intensive-care nurse who helped treat Mariela, told the Wall Street Journal. “They get whisked away and cooled, and now it’s like starting over.”

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