Frozen Back to Life: How Hypothermia Can Help Cheat Death
One hundred years ago, hypothermia was often lethal. Now doctors induce it to save people on the brink of death.
Robert Falcon Scott is dying, slowly succumbing to hypothermia in a tent pitched on the wastelands of the Ross Ice Shelf, full of the weary knowledge that he was not the first explorer to reach the South Pole—only the first to have lost an entire expeditionary party doing so.
It is 1912. Antarctica is as inaccessible as it is fraught with risk; and that, of course, is its attraction, leading men to pit their lives against its challenges. Having been beaten to the pole by Roald Amundsen’s Norwegian expedition, Scott now embarks on a race of a different kind: the scramble to write letters to the next of kin of his expedition team, telling of the men’s brilliance and honor and how he was responsible for leading them to their deaths. Time is against him.
Not only can temperatures freeze exposed flesh in seconds, but the continent’s great sheets of ice hold water locked away, and less than a single inch of rain falls inland each year. The Ross Ice Shelf is a desert, and it will attempt to dehydrate and desiccate Scott’s body. With much of the continent thrust two miles above sea level, Scott is high enough to make heavy exertion uncomfortable, even for the acclimatized. That’s not to mention the scouring Antarctic winds, which will carry heat away from his body, driving his temperature down. All told, Antarctica is a continent of fierce extremes: the coldest, the highest, the most parched. Its climate has made it uninhabitable for all but the last hundred years of human history.
Bleak though Antarctica may be, it’s important to consider how Scott’s body reacts to his plummeting temperature because that process is the key to an extraordinary advance in future medical technology.
1912: Shivers, Then Merciful Sleep
Scott’s physiology is designed to battle for him, to give him his best chance of survival. As he writes, he feels the heat draining out of his hand. The blood vessels that run through his body’s periphery, carrying hot blood to his skin’s surface and losing that heat uselessly to the outside world, are constricting. His body hair stands on end to trap more air close to his skin. Both of these measures are an effort to reduce conductive heat loss. In the Antarctic environment, however, this physiological strategy is next to useless.
Next, Scott begins to shiver uncontrollably, generating enough heat to slow the drop in temperature. This shivering is more than the casual tremor we might feel at a bus stop in midwinter; Scott’s muscles shake as hard as they can, consuming fat and carbohydrates ravenously. This last attempt at staving off death becomes an act of physical endurance in itself. It continues while there is enough fuel to do so. But shivering, no matter how athletically, is merely the body’s method of buying time in the hope that something in its external environment will change for the better.
As deep hypothermia proceeds, it alters Scott’s mind, making him irritable and possibly irrational. When his body’s reserves of fuel run out, the shivering stops—which only accelerates the rate at which he cools. Mercifully, something that looks like sleep follows, as the electrical activity in his brain begins to fail. He slips into a coma well before the impairment of his heart muscle’s cell membranes, the gatekeepers of electrical stability in that organ. Frenzied anarchic rhythms may follow, the heart writhing uselessly like a bag of worms before finally coming to a standstill. With his heart no longer beating, his body is deprived of fresh oxygen.
But at such low temperatures, the rate at which Scott’s cells fail and die is dragged out. The normal window of a few hundred seconds when his brain is dying, yet his circulation might still be reestablished, is instead stretched to many minutes.
This window, elongated by cold temperatures, becomes crucial to medical practitioners in the years ahead. Here’s how hypothermia has today become an asset to medicine, a tool for cheating death.
1999: Miracle Under the Ice
In May 1999, three junior doctors, Anna Bågenholm, Torvind Naesheim, and Marie Falkenberg, were skiing off trail in the Kjölen Mountains of Northern Norway. The beautiful evening was one of the first days of eternal sunshine at the start of summer. All three were expert skiers; Anna began her run confidently.
But Anna unexpectedly lost control. Torvind and Marie watched from afar as she tumbled headlong into a thick layer of ice covering a mountain stream. Anna fell through a hole in the ice, her head and chest trapped beneath the frozen surface. Her clothes began to soak, their extra weight carrying her deeper, dragging her downstream with the current and farther beneath the ice.
Torvind and Marie arrived just in time to grab her ski boots, stopping her from vanishing under the lip of the ice. Anna was lying faceup with her mouth and nose out of the water in an air pocket. She continued to struggle, freezing, in the Arctic stream.
None of the three could have been in any doubt about the seriousness of the situation. Even in those first minutes, Anna’s core temperature was beginning to plunge. Torvind called for help on his mobile phone. Two rescue teams were sent, one from the top of the mountain, on skis, and another from the town of Narvik at its base. The ski team arrived first, but the snow shovel the group had brought couldn’t break through the thick covering of ice.
Forty minutes after Anna became trapped, her desperate thrashing stopped, and her body went limp. The hypothermia, now profound enough to anesthetize her brain, would soon stop her heart. Another 40 minutes passed before rescuers arrived with a more substantial shovel that could break through the ice.
Anna’s body, lifeless and blue, was pulled out of the stream. She had stopped breathing and was without a pulse. As the resuscitation effort began, the challenge Anna faced seemed insurmountable. Her core temperature was perhaps more than 36°F lower than it should have been.
The key to good resuscitation is to keep the blood supplied with oxygen and moving around the body. This is achieved by breathing for the patient and then compressing the chest rhythmically to provide something approximating circulation. None of this is as efficient as the body’s native heartbeat and breathing, but it buys time. In principle, it sounds straightforward. In practice, there is perhaps nothing that adequately describes the sickening, repetitive crunch of ribs beneath the heel of the rescuer’s hand or the rising sense of desperation that the rescuer feels as the minutes tick by.
Just before 8 p.m., more than an hour and a half after she fell into the stream, Anna was whisked onto a helicopter. While the aircraft was moving speedily across the Norwegian landscape, the struggle to save Anna’s life became a desperate scramble. Helicopters, with their cramped conditions and deafening noise, are among the most difficult places to work.
When the helicopter touched down at Tromsø University Hospital, Anna’s heart had not beaten for at least two hours. Her core temperature, 56.7°F, was lower than any surviving patient’s in recorded medical history. This was genuine terra incognita. Further attempts to resuscitate Anna could proceed only in the knowledge that in similar situations, past medical teams had always failed.
But the team at Tromsø decided to continue. There was still the glimmer of hope that the terrible cold might also have preserved her brain.
Mads Gilbert, the anesthetist leading the resuscitation effort, moved Anna to the operating room. Raising her temperature was going to be a massive challenge. Warm blankets and heated rooms alone wouldn’t be nearly enough. Raising Anna’s whole body temperature through all those missing degrees would take an enormous amount of energy—equivalent to the boiling of dozens of kettles of water. To do this quickly and without doing harm in the process, Mads knew Anna would have to be put on a heart-lung bypass machine, the sort of device normally reserved for open-heart surgery. By removing Anna’s chilled blood, circulating it in a bypass machine, and heating and then returning it to her lifeless body, doctors could raise her core temperature rapidly. At least that was the theory.
Thirty minutes after Anna was established on the heart-lung bypass machine, her core temperature had increased by more than half, to 87.8°F. The heart, its molecular machinery now warm enough to work again, stuttered at first, unable to regain its own essential rhythm. But eventually, electricity began to flow through the muscle of her heart, followed by waves of contraction. A little after 10 p.m., Anna’s heart started to beat independently for the first time in at least three hours.
But the fight was far from over. During the scramble to save Anna’s life, the team had damaged an artery behind the collarbone on the right side of her chest. The hemorrhage that followed was made far worse by Anna’s hypothermic state because blood loses much of its ability to clot at low temperatures. The team now faced the possibility that she could bleed to death. Cardiothoracic surgeons had to open her chest, isolate the bleeding artery, and stop the hemorrhage. After hours of work by dozens of people, she was finally stable enough to be transferred to the intensive care unit.
While there, Anna miraculously survived lung failure and kidney failure and opened her eyes for the first time after just 12 days. She found herself paralyzed from the neck down, alive but quadriplegic.
Thankfully, Anna’s paralyzed body did not remain that way. It wasn’t an irreversible injury to her spinal cord that had left her unable to move. Instead, her peripheral nerves, damaged by the extremes of cold, had failed. Slowly but surely, these nerves and her flaccid muscles began to regain their function. It would ultimately take six hard years of rehabilitation, but the day came when Anna was well enough to ski and return to her training as a doctor. She specialized in radiology and now works at the hospital that saved her life.
Anna Bågenholm is an extraordinary survivor. Against seemingly impossible odds, doctors exploited her profound hypothermia to resuscitate her. While her survival occurred in the context of an accident, other patients continue to benefit from hypothermia by design.
2010 and Beyond: Hypothermia Saves Lives
Esmail Dezhbod’s symptoms had begun to worry him. He felt pressure in his chest, at times great pain. A body scan revealed that Esmail was in trouble. He had an aneurysm of his thoracic aorta, a swelling of the main arterial tributary leading from his heart. This vessel had doubled in size, to the width of a can of Coke.
Esmail had a bomb in his chest that might go off at any moment. Aneurysms elsewhere can usually be repaired with relative ease. But in this location, so close to the heart, there are no easy options. The thoracic aorta carries blood from the heart and into the upper body, supplying oxygen to the brain, among other organs. To repair the aneurysm, flow would have to be interrupted by stopping the heart. At normal body temperatures, this and the accompanying oxygen starvation would damage the brain, leading to permanent disability or death within three or four minutes.
Esmail’s surgeon, cardiac specialist John Elefteriades, MD, decided to carry out the procedure under the conditions of deep hypothermic arrest. He used a heart-lung bypass machine to cool Esmail’s body to a mere 64.4°F before stopping his heart completely. Then, while the heart and circulation were at a standstill, Dr. Elefteriades performed the complicated repair, racing the clock while his patient lay dying on the operating table.
I was there to watch this remarkable feat of surgery. Though Dr. Elefteriades is an old hand with hypothermic arrest, he says that every time feels like a leap of faith. Once circulation has come to a standstill, he has no more than about 45 minutes before irreversible damage to the patient’s brain occurs. Without the induced hypothermia, he would have just four.
The doctor lays the stitches down elegantly and efficiently, making every movement count. He has to cut out the diseased section of the aorta, a length of around six inches, then replace it with an artificial graft. The electrical activity in Esmail’s brain is, at this point, undetectable. He is not breathing and has no pulse. Physically and biochemically, he is indistinguishable from someone who is dead.
After 32 minutes, the repair is complete. The team warms Esmail’s freezing body, and very quickly his heart explodes back to life, pumping beautifully, delivering a fresh supply of oxygen to his brain for the first time in over half an hour.
A day later, I visit Esmail in the intensive care unit. He is awake and well. His wife stands by his bed, overjoyed to have him back.
To cure Esmail, the surgeons had to come close to killing him—using profound hypothermia to buy his survival. Within a century, we have come to understand the process that killed Robert Falcon Scott—and learned how to use it to our advantage. Esmail and Anna are living proof that these physical extremes can cure as well as kill.
Extreme Medicine, by Kevin Fong, MD, copyright © 2014 by Kevin Fong, is published by The Penguin Press, a member of Penguin Group (USA) LLC, penguin.com.