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Cold snap raises risk of frostbite, hypothermia

No major power outages, no snowfall records and only a few snarls on Interstate 93.

What this week’s winter storm and severe cold snap did bring to Concord were near-record low temperatures and the risk of hypothermia and frostbite for many people, across all walks of life.

While every individual’s risk for hypothermia is unique – dependent largely on their health – temperature and length of exposure are the most important factors in determining when someone is at risk for frostbite, said local emergency physicians.

Weather forecasters warned that temperatures this morning, even without the windchill, could drop to minus 18 degrees. Exposed skin can suffer frostbite in 30 minutes in those conditions, according to the agency.

Left untreated, the skin freezes and dies from lack of blood. In the most extreme cases, frostbite necessitates amputations.

At first, however, frostbitten skin is itchy and discolored. It can look waxy and feels numb. This level of frostbite, often called frostnip, does not cause permanent damage if the skin is rewarmed quickly.

If not, blood vessels continue to constrict and the skin tissue in the area freezes and hardens. The skin will be slightly numb, slightly wooden and look more pale than frostnip.

The real effects of this more intense freezing don’t appear until about 12 or 24 hours later, when blisters form on the skin. In cases of second-degree frostbite, skin tissue is permanently damaged and will be predisposed to frostbite in the future.

If the skin is not warmed quickly after second-degree frostbite, the tissue can die and would need to be amputated.

Frostbite is actually a side effect of the human body trying to survive extreme cold temperatures without adequate protection.

It’s the body’s way of fighting off hypothermia, a potentially fatal drop in the body’s core temperature.

Frostbite starts when blood vessels close to the surface of the skin contract, to direct more warm blood to body parts and organs essential for survival.

Hypothermia happens when the body can’t do enough to maintain a healthy core temperature. Like frostbite, it’s also caused by exposure to low temperatures, but “those temperatures don’t need to be extreme if they are consistent over a long period of time,” said Thomas Trimarco, an assistant professor of medicine at the Geisel School of Medicine at Dartmouth and an emergency room physician at Dartmouth-Hitchcock Medical Center in Lebanon.

The risk hypothermia poses to people depends largely on their health, said Robert Rix, an attending physician at Concord Hospital’s emergency department.

For people in good health, the slowing of the central nervous system “may just initially be a little bit of confusion, slurring of speech, and they may forget something they just did,” Rix said.

“If it continues, you get stuporous, delirious; you lose fine motor coordination, and can’t make your fingers work. For people who are outside – hunters, hikers – that means if you try to start the fire too late, you can’t use your fingers and you can’t even do it,” he said.

However, “the people that are at big-time risk are people who walk a fine line of health anyway,” he said.

Hypothermia puts immense stress on the heart as it slows and becomes susceptible to arrhythmia, and as a person’s balance and confusion worsens, they are at an increased risk of falling.

Hypothermia is particularly dangerous because some of its earliest symptoms are confusion and poor judgement, said Trimarco.

As the nervous system slows down from exposure to the cold temperature, patients will find they have decreased coordination, increased confusion and even amnesia, he said.

By the time the body’s temperature has reached 91 degrees, they’re apathetic to being cold and often don’t make good decisions to warm up.

The good news?

“You’re not dead until you’re warm and dead,” Trimarco said.

Hypothermia is reversible, even in some cases when a patient appears to have died.

A 2009 article in Emergency Medicine Practice cited known cases of a child who survived hypothermia with a core body temperature of 57.6 degrees Fahrenheit and an adult who survived at 56.7 degrees.

Because of the risk of heart arrhythmia, patients in extreme cases of hypothermia have to be handled delicately, Trimarco said.

But if they are warmed quickly and thoroughly enough – with warming blankets, intravenous fluids, warm water placed around their organs or even by having their blood removed, warmed and pumped back into their body – “with aggressive treatment, many are resuscitated, and they do well, with limited disability, if any.”

Both Rix and Trimarco stressed that winter isn’t the only time to be concerned about hypothermia.

The states with the highest rates of death from hypothermia are in milder climates such as South Carolina, or high elevations such as Wyoming, according to the Centers for Disease Control and Prevention.

(Sarah Palermo can be reached at 369-3322 or spalermo@cmonitor.com or on Twitter @SPalermoNews.)

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