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FROSTBITE; don’t freeze your @#% off!

 

I recall the story, a few years back, when living in Alaska, of an adventurer who had, in very early spring, embarked upon a long ski traverse. Beginning deep in the mountains of the Brooks Range, he headed south, his only companion an icy and relentless wind at his back. By journeys end he’d suffered frostbite to both cheeks of his buttocks. Imagine if he’d been traveling north.

 

As a species, humans are poorly adapted to cold. To survive unclothed, at rest, we require an ambient air temperature of 82 degrees to maintain a normal internal temperature, roughly 98.6, somewhat higher than the environment, the heart, lungs and other large organs generating heat as they go about their business. To survive in cold climates we make the conscious choice to put clothes on, not only to avoid embarrassment but also hypothermia -body core temperature below 95 degrees- and frostbite –literally the freezing of tissue.

 

Skin temperature averages 91 degrees; sensation is lost at around 50, tissue will freeze at 28 degrees. Fluid in and between cells begins to crystallize, damaging blood vessels and causing formation of tiny blood clots. Cells become dehydrated and shrink; intracellular electrolytes reach toxic levels. As if this isn’t enough, more damage is done during rewarming, especially if done improperly; damaged cells release substances that promote further blood vessel constriction and clotting.

 

Frostbite most often affects the extremities, the feet being far more common than the hands. The ears and nose are also vulnerable. Frostbite has been reported (no snickering here) on the scrotum and penis of joggers, if you’ve ever headed out on a run on a brisk winter morning, not really noticing that tailwind, only to return with your gloves or hand stuffed into your pants you understand how this is possible.

 

Cold alone is rarely responsible for frostbite, seldom arriving unannounced, usually accompanied by some other event like an accident or hypothermia. Broken bones and twisted joints cause disrupted circulation, limiting the flow of warm blood. A flat tire, broken binding or snow machine, a sudden storm, can turn a pleasant outing into an ordeal. The mention of frostbite conjures images of mountaineers struggling up some distant peak. A study of 125 cases from the Canadian province of Saskatchewan revealed 46% were directly related to alcohol, 17% some psychiatric component, and 15% due to vehicle failure. Tight fitting clothing, jewelry, and medical conditions such as diabetes may decrease circulation contributing to frostbite.

 

Hypothermia is perhaps the most common predisposing condition causing frostbite. Both conditions failure to either produce or retain adequate heat in response to a cold challenge. While hypothermia is life threatening, frostbite is merely limb threatening. As body temperature drops, less blood is circulated to the skin surfaces and appendages, a protective reaction known as the shell core shunt. This makes the extremities far more vulnerable to freezing.

 

Assessment of Frostbite

Frostnip

Frostnip is the beginning of ice crystal formation as the skin begins to freeze. Prompt warming prevents deeper freezing and tissue loss. The affected area appears gray or white (pink or red in darker skinned people). Skin will feel cold and stiff upon examination but will still be pliable over unfrozen deeper layers of skin, muscle and bone. Rewarming may be painful. Swelling and discoloration may appear, but no blistering.

 

Frostbite

Frostbite occurs as freezing deepens. The extent of damage is difficult to estimate initially; only several days post rewarming do we begin to get an idea of the depth of injury. This makes categorization of injury, often expressed as degrees, similar to burns, speculative and initial treatment of all depths of frostbite is the same. Skin color varies from yellowish, white or blue and feels hard or waxy to the touch. The extremity becomes difficult to use and may feel club like. Skin is no longer pliable and there is complete loss of sensation. Rewarming will be very painful. Blisters appear which may be clear or blood filled. In severe cases skin will be purple or even black.

 

Treatment

Rubbing frozen skin with snow and ice was the standard treatment for frostbite until the 1950’s, developed by Baron de Larrey, surgeon for Napoleon’s army during the invasion of Russia in the winter of 1812 – 1813. He watched as soldiers thawed frozen hands and feet over blazing fires only to freeze them all over again during the next days march. Larrey concluded that heat was bad for frostbite. He was partially correct; direct heat from fires does not afford the best outcome. Even worse was thawing then refreezing of tissue.   

 

Treat Early

Frostnip should be warmed immediately, at the first sign of numbness as it can quickly progress to frostbite. Skin to skin is an effective if unpleasant way to warm an extremity. Maybe as simple as turning your face away from the wind and warming with a hand, or placing a cold hand in an armpit. Rapid swinging, or windmilling of arms, quickly forces blood into the fingers. This can be done with the feet as well, though it takes much longer; swing the affected leg behind and in front of you relaxing the ankle –like kicking a ball, try 50 – 100 times per foot. More than once I’ve offered up my warm belly to a companion with extremely cold or numb feet -in one case due to an ‘extra’ pair of socks put on especially for summit day, they only made boots fit tighter slowing circulation. Place the affected extremity up under clothing; bare skin to bare skin, otherwise warming is just too slow. Warming by this method takes some time, 15 – 30 minutes or more. Treatment should continue until all feeling returns and the extremity feels warm.

 

Treat for Hypothermia

If your body temperature has begun to drop, shunting of blood away from the extremities has begun. Seek shelter. Put a hat on; up to 80% of heat loss occurs thru the head. Eat some food. Exercise to produce heat.

 

Rapid Rewarming

Some cells in frostbitten tissue are dead, some remain unaffected, and a large number have been injured but will either heal or die depending on treatment. Two conditions are critical to outcome of frostbite: how it is rewarmed and whether refreezing occurs.

Treatment of choice -rapid rewarming by immersion in circulating warm water -is best accomplished at a medical facility where conditions such as water and ambient temperature can be controlled and pain, anti-inflammatory, antibiotic and tetanus medicines are available. Better, in most cases, to walk out to help leaving the extremity frozen than to attempt field rewarming. Imagine trying to stuff a blistered hand back into a glove or mitten, a blistered foot into a boot then walking on it. It may be impossible to protect from trauma and refreezing. Tissues that remain frozen longer will take longer to thaw but no correlation has been shown between length of time frozen and subsequent damage.

 

As tissue thaws ice crystal formation is halted, small blood vessel re-dilate, pain can be extreme. Rewarmed tissue will appear swollen, with huge blisters, and dark blue to black in severe cases.

 

If reaching medical care is impossible field warming may be an option. Keep in mind the victim will usually require carry out or air evacuation. Shelter should be constructed. Anti-inflammatory drugs such as ibuprofen reduce pain, swelling and blood clots. Immerse the extremity in warm water, 104 – 108 degrees (lower temperatures are less beneficial to tissue survival, higher temperatures will cause burns). Temperature can be estimated with an unaffected hand, it should feel quite warm but not uncomfortably hot, about bath temperature. The rewarming process takes 15 – 30 minutes, until skin becomes pliable. Be ready to add warm water to keep the temperature up.

 

Once warmed the area needs to be protected from refreezing and trauma. Aloe gel may improve swelling and help prevent infection, place dry dressings over affected areas and between digits. Splint extremities with plenty of padding, be sure to monitor swelling and loosen if needed. Continue regular doses of ibuprofen.

 

Frostbitten parts used to be summarily amputated early on; now surgical amputation should be delayed for several weeks to a month or more ensuring all possible chance for recovery. Spontaneous amputation will occur on its own, an unpleasant but reportedly painless process.

 

DO NOT

Use a car heater, heating pads, fires or other direct heating source for rewarming, these methods cause greater swelling and more damage in the long run. If spontaneous rewarming is inevitable, stop and complete the rewarming as described if at all possible. Do not try to prevent spontaneous warming by packing an extremity in snow or ice.

 

Other Cold Injuries

Trench foot

Develops with prolonged exposure to cold and wet conditions above freezing, like in the trenches. Can affect hands as well as feet. Numbness is common due to impaired circulation. There will be redness, swelling and pain. Blisters may be present and are susceptible to infection. Tissue damage can occur if this condition persists for days to weeks.

There will be a history of long-term exposure. Dry and warm the area. Treat skin for infection with gentle cleansing, antibiotic ointment and clean dry dressings. Make the effort to take care of your hands and feet by drying and warming them each day.

 

Frostbite prevention

·         Ensure optimum heat production and conservation of that heat once produced. Stay fed and hydrated. Avoid overexertion by keeping a sustainable pace; panting compounds fatigue and fluid loss.

·         Use good judgment. Be prepared for emergencies. Carry extra warm clothes, warm boots and gloves in your vehicle in case of breakdown or an accident.

·         Pay attention to your feet and face and ears especially for developing numbness, which has a way of sneaking up on you.

·         Look for clothing that helps wick moisture away from the skin. Top off with a breathable windproof layer. Dress in layers and stop to remove layers to avoid sweating which wastes energy and fluid. Mittens are warmer than gloves because they have less surface area and air cannot circulate between the fingers. Runners know the importance of at least a light pair of gloves and headband. briefs with a nylon wind panel protect important parts. Poorly fitting boots are notorious for causing frostbite. Test all footwear before long trips.  Some people use vapor barrier boots or socks, which are probably most useful on multi-day backcountry trips because they keep footwear from becoming saturated with water then freezing, just be sure to have spare dry socks to change into.

·         Goggles are indispensable in winter and for mountaineering, much warmer than sunglasses. Neoprene face masks are the best, most come with small holes around the mouth, cut these out to make an opening big enough to breath out of and to keep ice from blocking the smaller holes. Chemical warmers are worth a try. They seem to work better in gloves than boots but are definitely worth carrying. Don’t leave boots outside when winter camping. Wipe out any moisture with a bandana. Store liners in you sleeping bag. Polargaurd booties make good winter camp shoes.

 

Kids

Children are at greater risk for frostbite; they lose heat from their skin more rapidly, may be reluctant to come in from playing and may not pay attention to early signs of cold injury such as numbness. Dress your child in layers, make sure they come inside to warm up at regular intervals. Look for frostnip, whitish or grey patches of exposed skin, an early warning of impending frostbite. Cover exposed areas. Change wet clothes.

 

ATF: alcohol, tobacco and firearms, the axis of evil.

Ok, I don’t know about firearms but cigarettes and alcohol should be avoided. While it’s hard to imagine a truly fun outing without these ingredients keep in mind that nicotine causes both immediate and long term constriction of blood vessels. Alcohol may temporarily make you feel warm; it causes blood vessels to dilate hastening heat loss. Alcohol also impairs judgment leading to poor decision-making and accidents.

 

Frigid temperatures and snow are part of the fun of winter. Frostbite is largely preventable with good planning, and decision-making. The quality of care for frostbitten extremities is critical for the best recovery, and don’t forget what your mom told you; it’s cold out there, put a hat on.

 

 

 

John Schwieder is a flight paramedic with San Juan Regional Air Care in Farmington, NM. He is an instructor with Wilderness Medical Associates and a photographer. His hypothermia article can be found at www.wilderness.pics.com along with his collection of wildlife, landscape and adventure photos.