cold injuries
TRANSCRIPT
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
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
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