COLD INJURY : LOCAL TISSUECOLD INJURY : LOCAL TISSUE

COLD INJURYCOLD INJURY

• Freezing–Frostnip–Frostbite

• Non Freezing–Trench foot – Immersion foot–Childblains

Patophysiology of Tissue FreezingPatophysiology of Tissue Freezing

• Temperature below -2°C• Distal area of body and area with high surface

to volume ratio; ears, nose, fingers and toes• As tissue begins to freeze, ice crystals are

formed within cells. As intracellular fluids freeze, extracellular fluid enters cell and extracellular salts increase due to the water transfer.

• Cells may rupture due to the increased water and/or from tearing by the ice crystals.

• Do not rub tissue; it causes cells tearing from the ice crystals

• As the ice melts, there is an influx of salts into the tissue further damaging the cells membrane.

• Cells destruction results in tissue death and loss of tissue.

Cold Response

Mild Frostnip

Superficial Frostbite

Deep Frostbite

Sensation Painful May have sensation

Numb Numb

Feels Normal Normal Soft Hard

Color Red White White White

FrostnipFrostnip

• Freezing of top layers of skin tissue• Reversible• White, waxy skin, top layer feels hard, rubbery

but deeper tissue is still soft• Numbness• Most typically seen on cheeks, earlobes,

fingers and toes

Treatment of FrostnipTreatment of Frostnip

• Rewarm the area gently, by blowing warm air on it or placing the area against a warm body part (partner’s stomach or armpit)

• Do not rub the area – this can damage the effected tissue by having ice crystals tear the cell

FrostbiteFrostbite• Skin is white and “wooden” feel all the way

through• Numbness, possible anesthesia

Superficial Frosbite (2Superficial Frosbite (2ndnd degree Frosbite) degree Frosbite)– Destruction of skin layers,

resulting blistering & minor tissue loss.

– Blisters are formed from the cellular fluid released when cells rupture.

– Skin redness in fair individuals, Grayish discoloration in darker skinned individuals.

– Persistent cold sensitivity in the area

Deep FrosbiteDeep Frosbite– Loss of sensation with pale, yellow,

waxy look if unthawed.– Poor capillary refill.– Tissue loss, can involve muscle and

bone– Hemorrhagic bullae form in 3rd

degree injuries at 12-35 hours unless re-warming is rapid.

– Red discoloring 1-5 days after injury.

– 4th degree characterized by gangrene, necrosis, auto-amputation.

– Permanent anatomic and functional loss.

Rewarming of FrosbiteRewarming of Frosbite

• By immersion the effected part into a water bath of 40.5 – 43.3 °C.

• Remove constricting clothing• Monitor and maintain the warm water bath

temperature• Thawing is complete when the part is pliable

and color and sensation has returned• Discontinue the warm water bath when

thawing is complete

• Once rewarming is complete, the injured area should be wrapped in strile gauze and protected from movement and further cold

• If the person is hypothermic and frosbitten, the first concern is core rewarming. Do not rewarm the frostbitten areas until the core temp approaches 35 °C

Trench Foot – Immersion FootTrench Foot – Immersion Foot

• Caused by prolonged exposure of feet to cool, wet condition

• Occur at temperature as high as 15.5 °C if the feet are constantly wet

• Mechanism of injury: wet feet lose heat 25x faster than dry, therefore body uses vasoconstriction to shut down peripheral circulation in the foot to prevent heat loss

• Skin tissue begins to die because lack of oxygen and nutrients and due to buildup of toxic products

• Skin is initially reddened with numbness, tingling pain, and itching then becomes pale and mottled and finally dark purple, grey or blue

• The effected tissue generally dies and sluff off

• Involve toes, heels or entire foot• If circulation is impaired for > 6 hours there

will be permanent damage to tissue• If circulation is impaired for > 24 hours the

victim may lose the entire foot

Treatment Trench FootTreatment Trench Foot

• Careful washing and drying of feet, gentle rewarming and slight elevation

• Give Ibuprofen or other pain medication

Prevention of Trench FootPrevention of Trench Foot

• Keep feet dry by wearing appropriate foot wear, check feet regularly to see if they are wet

• If feet get wet (through sweating or immersion), stop and dry feet and put on dry socks

• Periodic air drying, elevation and massage will also help

• Change socks at least once a day and do not sleep with wet socks.

ChillblainsChillblains

• Caused by repeated exposure of bare skin to temperature below 15.5 °C

• Redness and itching of the effected area• Particularly found on cheeks and ears, fingers

and toes• Cold exposure causes damage to the

peripheral capillary beds, this damage is permanent and redness and itching will return with exposure

ChildblainsChildblains

• Symptoms:

• –initially pale and colorless

• –worsens to achy, prickly sensation then numbness

• –red, swollen, hot, itchy, tender skin upon rewarming

• –blistering in severe cases

ChildblainsChildblains

• Treatment

• –prevent further exposure

• –wash, dry gently

• –rewarm (apply body heat)

• –don’t massage or rub

• –dry sterile dressing

• –seek medical aid

ChildblainsChildblains

• •Prevention

• –keep dry and warm

• –cover exposed skin

• –wear uniform properly

• –use the “Buddy System”