FROST BITE

What is it?

Simply it is freezing of body tissue, which occurs with a prolonged exposure to sub zero temperature. There are two types; Frostnip (superficial frostbite) and Deep Frostbite. Frostnip is purely just discolouration of the affected areas, and after two to three days will completely clear with no real permanent damage. Deep Frostbite is where tissues inside the body freeze, and this obviously has real lasting effects with the chance of ending in amputation.

The main causing factor is external temperature, it needs to be sub zero but most cases are a result of periods of exposure of –15 degrees C. The wind and humidity are also factors, they assist heat loss by both convection and conduction. Altitude has a role too, the higher you are the less oxygen there is, and the less oxygen there is the more damage frostbite will cause. The patient’s hydration levels need also to be considered. The equipment that is employed will either assist or prevent frostbite; ill-fitting clothes can restrict blood flow and thus speed up the cooling of the injured area. Also, just the quality of the gear is an issue. So, winter mountaineering is quite possible one of the highest risk environments for frostbite injuries!

In Chamonix last year, there were about 80 cases of frostbite 75% of them were just superficial and only 8% resulted in amputation. So considering how many people must use the Chamonix hills throughout the year, 80 is a very small proportion. The trick to saving sufferers from amputations is to start treatment as soon as possible in the very early stages.

There are 3 main stages in the onset of frostbite:

1. Cooling and Frost Effects. With cooling of body there is peripheral vasoconstriction, this is where blood supplies to the extremities is reduced to help prevent heat loss and to keep the core temperature from dropping (which would result in hypothermia). With the reduction in blood flow there you get local stagnation of blood (this is where the blood pools) and with this the blood will become hyper viscous (harder for it too flow) and acidosis (the pH levels of the blood become more acidic). The major effect of all of this is a reduction of oxygen to the cells. Ice crystals will form in the extracelluar space (outside of the cells) and increase the osmarlatiy, which results in water leaving the cells thus causing dehydration. The speed of this net migration of water will determine the damage caused, and the mechanical action of the frost crystals will cause cell death.

2. Thawing and Progressive Necrosis. When you start re-warming the injured area the vasoconstriction of the frostbite is replaced by hypothermia. This again has a damaging effect to the tissue, there is a movement of liquids to the interstitial tissues which again results in a reduction of blood flow. The death of the epithelial cells, and the changing conditions on the basal membrane, start the coagulation cascade, which sees the blood clotting.

3. Permanent Lesions. There is more vascular damage and necrosis (cell death), and the course is Oedema (swelling) then Blistering followed by necrosis. This will start to occur after 48 hours after the assault. If treatment starts in this stage there is a very low success rate of saving the affected area from amputation.

The prognosis is very hard to make in the early days, Frostnip is easy to tell after 2-3 days where the normal colour will return to the affected site. Deep frostbite can take over 30 days, hopefully at this time you will start to see demarcation of the dead and healthy tissue. One can use Bone Scintiscon Scanning with Technetum 99 to see how much of the bone has died, but still this can give a false indication as to how much will remain alive.

Click here for a THP member's frostbite experiance....

Treatment
The ideal treatment is to re-warm the injured area in warm water (38 degrees C) as soon as you notice discolouration, but obviously this is hard/impossible to do on a climb surrounded by ice! The worse thing you can do is re-warm and then allow re-freeze. It is better to leave the suffering area cold and re-warm once you are in a suitable place that will not allow refreeze, i.e. back in the bar in town!

If you do experience any level of frostbite you really need to go and see the doctors in the hospital, and ideal you want to be in Chamonix – where they are the experts on frostbite, even superficial frostbite requires I.V. drugs. In this case you can expect to be on Aspirin (a mild vasodilator), buflomedil a stronger vasodilatior and a NSAID painkiller. A vasiodilator is a drug which dialates your blood vessels, basically making your arteries wider and increasing blood flow to your extremities. (NSAID stands for non steriodal anti-inflamtory drug)

For deep frostbite, there are some very powerful drugs involved. Iloprost is given on a slow drip for 6 hours a day, this treatment will last for 10 days. It is a very powerful vasodilatator so you will swell up, turn bright red, suffer massive headaches and just feel pretty shit for the 6 hours. You will be on Aspirin throughout your stay, along with a glucose saline solution to help you maintain a high blood volume level, which will help force blood back into the affected areas. As you can no really move and there is a risk of blood clots in your system a low molecular weight anti-coagulant will be given, probably Herprin. It is also important that you keep infection away, so there will be some sort of antibiotic in your I.V. cocktail.

To combat the Oedema the affected area will be raised. After a week or so, you will under go some minor surgery. You will have debridlement of your skin; they will cut all the dead skin off! This is really to help the development of new skin. Amputation will be left as a very last option, and in many cases the doctors will opt for auto-amputation; basically they leave the body to rot and the dead areas will fall off over an extended period of time.

Lasting Effects
There will be increase sensitivity to temperature, partially the cold. In the case of amputation cold conditions can be enough to spark off phantom feelings. The assaulted area will suffer from hyper hidrosis (increased amount of sweating). Amputations will results, partially in regards to feet, tendon readjustment (the ligaments will have to re-learn the new balance points of the foot). There have been reports of earlier onset of arthritis and osteoporosis.

So over all PREVENTION IS THE BEST PLAN and smoking will only make things worse, Yale University conducted a study which showed that smokers are a lot slower at re-warming than non-smokers. So another rule, DON’T SMOKE!

A.Johnson