Freezing and Near Freezing Tissue Injuries

TLO

• Given a simulated casualty, treat cold injuries, in accordance with the references.

ELO’s

• From a given list select the correct definition of frostbite.

• From a given list select the correct two mechanisms of injury for frostbite.

• From a given list select the correct signs and symptoms of frostbite.

• From a given list select the correct favorable post thaw signs of a frostbite injury.

ELO’s

• From a given list select the correct unfavorable post thaw signs of a frostbite injury.

• From a given list select the correct field treatment for frostbite.

• From a given list select the correct primary field treatment consideration when treating frostbite in the field.

ELO’s

• From a given list select the correct methods to reduce the chance of becoming a frostbite casualty.

• From a given list select the correct definition of immersion foot.

• From a given list select the correct mechanism of injury for immersion foot.

ELO’s

• Given a list of categories and characteristics match the category of immersion foot to its characteristics.

• From a given list select the correct field treatment of immersion foot.

Napoleon’s Retreat from Russia

Napoleon Retreats from Russia

• Entered Russia with an army of 250,000

• Retreated with only 20,000 soldiers (only 350 were combat effective)

• Temperatures dropped to –38 degrees C

WWII

• In November and December 1942, the Germans performed 15,000 amputations for cold injuries.

FROSTBITE

• Definition: Frostbite is the actual freezing of tissue.

Mechanisms of Injury

• Actual freezing of the tissues. – Ice crystals form extracellularly and grow by

extracting water from the cells.– Cells are injured by dehydration and electrolyte

disturbances.– Ice crystals that form intracellularly are much

more damaging, but this requires much colder temperature and faster freezing time.

Mechanisms of injury

• Obstruction of blood supply – Cells lining the capillaries and small veins are

damaged, this allows serum to leak out into the tissues and activates coagulation cascade

– Serum leakage increases viscosity and reduces blood flow.

– The reduced fluid volume and activation of coagulation cascade causes obstruction.

– This obstructs blood flow and circulation, this produces irreversible damage.

Frostbite Signs and Symptoms

• Sensation– Numbness– Paresthesias– Pain – after extremity is rewarmed

Frostbite Signs and Symptoms

Appearance:• Pale/White to yellowish

white to gray• Bluish tinge/mottled blue• Erythematous ( after

rewarming)• Blisters- clear to

hemorrhagic• Black (days to weeks out)

Frostbite Signs and Symptoms

• Sensation– Loss of pliability– Waxy– “frozen chicken”– “block of wood”

Late Frostbite Signs and Symptoms

• Blisters/edema will occur approximately 6-24 hrs after injury

• Black hard eschar appears within 4-10 days if severe frostbite

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Frostbite Classification

• Classification must be done retrospectively.• 1st- Erythema, edema, tingling, burning.• 2nd- CLEAR BLISTERS, edema,

anesthesia or paresthesias.• 3rd- Entire thickness of skin and

subcutaneous tissue. Hemorrhagic blisters.• 4th- Entire thickness of skin including bone.

Baron de Larrey

• Chief of the Medical Corps for Napoleon’s Army

• Organized the concept of the “flying ambulance”

• Captured by the Prussians and sentenced to death

Baron de Larrey

• Made observations about frostbite

• Soldiers who thawed hands over bonfires and allowed them to refreeze did worse than those who did not rewarm them

Baron de Larrey

• Made correct conclusion that frostbite victims should not rewarm the affected extremity and allow it to refreeze nor should they rewarm it over open flames

Baron de Larrey

• However, his recommendation was to rub the frostbitten extremity with snow.

• “when some external part of the body is caught by the cold…it is necessary to rub the affected part with substances containing very little calorick”

Primary Consideration

• Do not rewarm the extremity if there is a chance of it refreezing.

• This will greatly increase the amount of tissue damage.

Field Treatment (Frostbite)

• Rapid rewarming produces the best results.• Immersion of the affected part in warm

water.• Water temperature: 99-102 (F) until tissues

of distal extremities are flush• This is extremely painful: NARCOTIC

ANALGESIA.

Frostbite Treatment

• Forced hydration- IV fluid if necessary

• Motrin 400mg BID before rewarming if possible

• Aloe Vera 99% tid• Daily Betadine Soaks• Daily dressing/bandage

changes• Denali Protocols:Toradol

Frostbite Treatment

• No nicotine

Blister Management

• Do not aspirate hemorrhagic blisters

• Leave intact• If blisters rupture

apply topical antibiotic

Amputation

• Keep orthopedic surgeons away from patient

• Amputate late

Experimental Treatments

• Vasodilators• Heparin• Hyperbaric oxygen• Topical nitrates

Favorable Signs (Frostbite)

• Warmth of tissue.• Normal tissue color.• Preservation of sensation.• Blisters extending all the way distally on

the affected part.• Edema persisting more than 24 hours.• Good capillary refill.

Unfavorable Signs

• These signs indicate a poor prognosis with probable tissue loss.– Complete absence of edema.– Cyanotic tissue.– Continued loss of sensation.– Affected areas continue to stay cold.

QUESTIONS?

Frostbite Risk Factors/Prevention

Frostbite Risk Factors/Prevention

• Vasoconstriction caused by hypothermia

• Cold Induced Vasodilation (CIVD)- 59F

Frostbite Risk Factors/Prevention

• Keep whole body warm- “if feet are cold put on a hat”

• Adequate clothing• Activity• Maintain nutrition

status• Maintain hydration

Frostbite Risk Factors/Prevention

• Inadequate Blood Supply– Fractures– Dislocations– Shock– Dehydration

Frostbite Risk Factors/Prevention

• Inadequate Blood Supply– Tight boots/gloves– Tight harness/pack

• Ensure fingers and toes can move freely

Frostbite Risk Factors/Prevention

• Inadequate Blood Supply– Nicotine – potent

vasoconstrictor– Avoid nicotine-

• Must have strong command interest

Frostbite Risk Factors/Prevention

• Increased Heat Loss– Inadequate insulation– Wet gloves– Gloves versus mittens

Frostbite Risk Factors/Prevention

• Keep clothing/gloves dry– Off the deck– Dry in the evenings– Secure straps– Fleece liners are not an

outer layer

• Wear mittens instead of gloves – trigger finger

• Have dry gloves readily available

                                                                           

Frostbite Risk Factors/Prevention

• Increased conductive heat loss when in contact with metals and fuels

• Do not touch metals and fuel with bare hands- always use contact gloves.

• Avoid placing hands in “splash” zone

• Insulation for ice axes

Rewarming Cold Hands

• Set an acceptable time period for “cold hands”

• Whole body warmth• Conduction- skin to

skin – axilla, groin• Isometrics• Windmilling

Frostbite Risk Factors/Prevention

• Hand/Foot checks

Frostbite Risk Factors/Prevention

• Unwashed skin protective – minimizes insensible heat loss

Frostbite Risk Factors/Prevention

• Peak times– Completion of

movements– Night movements– Displacement- digging

in– Inexperienced

leadership

Questions?

Immersion Foot (Trenchfoot)

• Original term from WWI trench warfare

Immersion Foot

• 4500 American soldiers suffered from trenchfoot from 1943-1944 in WWII

Immersion Foot

• Falklands War– Trenchfoot prevalent –

70%

Immersion Foot

• Vapor Barrier boots can cause immersion foot

IMMERSION FOOT

• DEFINITION: Immersion foot is a non-freezing injury of the extremities in which the tissues are damaged.

Mechanism of Injury

• Occurs in wet cold (nonfreezing) environment

• Prolonged exposure• Cold induced vasoconstriction

– Nerve Injury– Epidermal Damage– ? Reperfusion Injury

Timeline of Injury- Signs and Symptoms

• Prehyperemic Phase– “cold and numb”– Pulses may be initially absent– Blanched, yellowish/white appearance– “walking on wooden limbs”

Timeline of Injury- Signs and Symptoms

• Hyperemic Phase- after rewarming– Can last 6-10 weeks– Characterized as deep, burning, throbbing ache– Erythematous initially- may become diffusely

blue/mottled/deep purple red– Increased warmth– Swelling– Blister/Intracutaneous Hemmorhage

Immersion Foot

Category(Immersion Foot) • Minimal- reddening of skin, slight sensory

changes.• Mild- Edema, sensory changes (reversible).• Moderate- Edema, redness, blisters,

intracutaneous hemorrhage, irreversible nerve damage.

• Severe- Severe edema, massive intracutaneous hemorrhage, necrosis, gangrene.

Field Treatment (Immersion Foot)

• Pat drying of extremity.• Gentle rewarming- damage may occur secondary

to reperfusion. • Elevation of affected extremity.• Bed rest.• Treatment after this is supportive.

– debridement, resection.– tetanus booster.– no nicotine.

Treatment of Immersion Foot

• Significant Risk of Infection• Pain is difficult to control

– Neurogenic pain• Wet gangrene-

– Look for fever, increased CPK and leukocytosis.– Treatment is early surgical intervention and sequential

amputations. Do not put these patients in water!– Severe chronic pain syndromes may develop.

Prevention

• Change out socks frequently• Dry out feet at night• Antiperspirants• Do not wear boots while in the sleeping

bag!

Review

• Frostbite Definition• Frostbite Diagnosis / Treatment• Frostbite Risk Factors / Prevention• Immersion Foot Definition• Immersion Foot Diagnosis / Treatment• Immersion Foot Risk Factors / Prevention