December 3, 2020

I, Science

The science magazine of Imperial College

Anna Bagenholm was under ice with a body temperature of 13.7 degrees celsius with no heartbeat for two hours, but managed to recover ...

Skiing post copy

“Nobody is dead until they’re warm and dead”. This old Norwegian saying saved the life of 29-year-old trainee doctor, Anna Bagenholm. Her extraordinary story demonstrates the surprising potential of hypothermia as a life-saving therapy…

In May 1999, Anna was skiing with two colleagues in the Norwegian mountains when she lost control of her skis and tumbled headfirst through sheet ice into fast-flowing, freezing water. Entirely trapped between ice and rocks, Anna found an air pocket at the surface, and somehow remained conscious for 40 minutes as her companions clung desperately to her feet and skis, trying in vain to drag her out. Eventually, however, Anna lost consciousness and her body went limp underwater as deep hypothermia set in and her heart stopped beating. Another 40 minutes passed before the mountain rescue teams arrived and she was finally freed.

A further hour passed as the rescue helicopter carried Anna to the nearest major hospital, more than 100 miles away. By this time, she had had no heartbeat for nearly two hours. On Anna’s arrival, the chief of the hospital’s emergency room observed that “she had completely dilated pupils. She was ashen, flaxen white. She was wet. She was ice cold when I touched her skin, and she looked absolutely dead.” An ECG showed no signs of life and defibrillation failed to revive her. Anna’s core body temperature was just 13.70C.

Nonetheless, the experienced medical team continued to resuscitate Anna, performing CPR as her blood was gradually and carefully warmed up via a bypass machine. After some time her body temperature returned to normal, and suddenly her heart started beating again. Anna awoke days later, and, although her kidneys and digestive system had failed, astonishingly, she had suffered no permanent brain damage. Following two months in intensive care, Anna made an almost full recovery, only suffering permanently from minor nerve damage in her hands and feet.

Shortly after her accident, Anna said: “As a medical person, I think it’s amazing that I’m alive.” Indeed, her body temperature of 13.70C is the lowest recorded temperature ever survived in a case of accidental hypothermia. So how did Anna live to tell her extraordinary tale? Ironically, it was the extreme hypothermia that stopped her heart that ultimately saved her. What made Anna’s situation unusual was that her body had already cooled down completely by the time she suffered circulatory arrest: During the 40 minutes that Anna struggled to breathe in the air pocket under the ice, the freezing water cooled her brain to an incredibly low temperature, causing the metabolic rate of her brain cells to fall to a point where they required very little oxygen. They were in a state similar to that of hibernation by the time Anna’s heart stopped beating, able to survive on just a fraction of the oxygen that they would need at normal body temperature. Had she suffered cardiac arrest sooner, at a higher core body temperature, she would certainly have been severely brain damaged, and probably wouldn’t have survived.

Hypothermia is clearly a double-edged sword. On the one hand, it throws the body’s systems dangerously out of balance, damages the integrity of cells, and prevents blood clotting – with disastrous consequences for patients who, unlike Anna, are bleeding from trauma. But on the other hand, it has the potential to save lives, and is used frequently by doctors in a therapeutic context. In open heart operations surgeons will commonly cool their patients to as low as 100C, allowing them to cut off the brain’s arterial blood supply for up to 15 minutes without causing brain damage. Partly inspired by Anna’s story, therapeutic hypothermia has also been introduced as a protective measure for victims who have suffered strokes and heart attacks, and several studies have demonstrated it’s effectiveness in helping babies who have been starved of oxygen at birth. However, some contest the use of therapeutic hypothermia as a mainstream procedure in certain situations, with one recent study questioning the degree of hypothermia required to protect heart attack patients.

Nearly fifteen years after her fateful accident, Anna now works as a radiologist in the very same hospital that saved her life. Her story will be remembered for years to come as an extraordinary example of survival against the odds.

 

IMAGE: Wikicommons