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Chapter 20
Cold-Related Emergencies
Cold-Related Emergencies
• Normal body temperature is 98.6°F.
• Body loses heat when surrounded by air
or water that is cooler than the body.
• Body temperature falls
• Cold injuries can result.
How Cold Affects the Body (1 of 2)
• Biologic defense mechanisms protect body
• Vasoconstriction
• Tightening of blood vessels
• Can cause discomfort, numbness, loss of
dexterity, cold injuries
• Shivering produces body heat.
• Stops when core temperature falls too low
or when there is no fuel.
How Cold Affects the Body (2 of 2)
• Physical activity produces heat.
• Heat loss after exertion if clothes are wet
• Proper hydration and nutrition help prevent
cold injuries.
• The colder the temperature, the greater the
potential of body heat loss.
• Physical changes from cold exposure can
impair ability to perform manual tasks.
Heat Loss From the Body
(1 of 2)
• Body temperature maintained by
balance of heat production and loss
• Shivering rapidly consumes calories.
• Heat loss occurs primarily through
skin.
Heat Loss From the Body
(2 of 2)
• Four mechanisms of heat loss:
• Conduction
• Direct contact with colder object
• Convection
• Loss of heat by air blowing over skin
• Evaporation
• Conversion of liquid on skin to vapor
• Radiation
• Heat given off to cooler air
• Primary method of heat loss
Susceptibility to Cold Injury
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Physically unfit
Dehydration
Very lean people
Elderly
Alcohol, caffeine
Smoking, chewing tobacco
Inadequate nutrition, illness, injury
Previous cold injury
Effects of Altitude
• Temperature, windchill are
considerations
• Air temperature drops 3.6°F
every 1,000 feet.
• Winds more severe
• More susceptible to frostbite
above 8,000 feet
Effects of Water
• Conducts heat away from body faster
than air.
• Body heat loss occurs 25 times faster
with wet clothing.
• Plunging into cold water can cause
irregular heartbeat, gasping,
hyperventilation.
• These can cause water inhalation,
heart failure, drowning.
Effects of Wind
• Increases potential for body heat
loss
• Windchill index integrates wind
speed and air temperature.
• Helps estimate risk of cold injury.
• Artificial wind can increase heat
loss.
Effects of Metal and Liquid
Fuels
• Can conduct heat away from
skin rapidly.
• Contact can cause almost
instantaneous freezing.
• Must use great care when
handling.
Minimizing Effects of Cold on
the Body
• Adequate clothing is key
• Layered clothing helps maintain proper body
temperature.
• Undergarments
• Should wick away perspiration
• Middle layer
• Synthetic pile, fleece, or wool
• Outer layer
• Waterproof, wind resistant, breathable, with
zipper
Nonfreezing Cold Injuries
• Can occur when conditions
are cold and wet, hands and
feet cannot be kept warm and
dry
• Chilblain
• Trench foot
Chilblain
• Painful, but causes little or
no permanent damage
• Can develop in 3 to 6 hours
if exposed to cold and
moisture
Recognizing Chilblain
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Swollen skin
Tender, hot to touch, itchy
Blisters
Aching, prickly sensation
Numbness
Care for Chilblain
• Get victim out of cold.
Trench Foot
• Serious injury, also called
immersion foot
• Develops when feet exposed to
moisture and cold for 12 hours or
longer
• Moisture softens skin, tissue loss
and infection occur
• Crippling injury can occur
Recognizing Trench Foot
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Itching, numbness, tingling pain
Swollen feet, pale skin cold to touch
Red, bluish blotches on skin
Sometimes open weeping, bleeding
Care for Trench Foot
• Dry the skin.
• Rewarm foot gradually.
• Cleanse weeping areas
with mild soap and water,
apply breathable dressings.
Freezing Cold Injuries
• Occur when air temperature is below freezing
(32°F)
• Frostnip
• Freezing is limited to skin surface
• Frostbite
• Freezing occurs deeper in skin
• Frostbite more common in military, mountain
climbers, explorers.
Frostnip
• Water freezes on skin surface
• Serious — could signal
impending frostbite
Recognizing Frostnip
• Red, swollen skin
• Painful
• Dry, cracked, sensitive skin from
repeated frostnip to same spot
Care for Frostnip
• Gently warm affected area.
• Place against warm body part.
• Blow warm air on area.
• After, area can become red
and tingling.
• Do not rub.
Frostbite
• Occurs when temperatures
drop below freezing
• Tissue can actually freeze
• Blood supply obstructed
• Affects feet, hands, ears,
nose
• Most severe consequence
= gangrene (dead tissue)
Recognizing Frostbite (1 of 2)
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White, waxy, or grayish yellow skin
Cold and numb
Tingling, stinging, aching
Stiff or crusty surface, soft underneath
Deep frostbite:
• Cold, hard, solid
• Blistering
• Cold, pale, waxy skin
• Pain stops
Recognizing Frostbite (2 of 2)
• First-degree
• Warm, swollen, tender
• Second-degree
• Blisters minutes to hours after thawing,
enlarge over several days
• Third-degree
• Small blisters, reddish blue/purplish fluid
• Fourth-degree
• No blisters, no swelling
• Numb, cold, white to dark purple
Care for Frostbite (1 of 2)
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Get victim to warm area.
Remove wet clothing.
Remove items that could impair circulation.
Seek medical care.
If affected part is partially thawed or victim is
remote:
• Place part in warm water. Add warm water
to maintain water temperature.
• Ear or facial injuries: apply warm, moist
cloths.
Care for Frostbite (2 of 2)
• After thawing:
• Place on stretcher if feet affected.
• Protect area from contact with clothing,
bedding.
• Place dry dressings between toes and
fingers.
• Slightly elevate to reduce pain and
swelling.
• Apply aloe vera gel.
• Provide aspirin (adults), or ibuprofen, or
acetaminophen.
Hypothermia (1 of 3)
• Life-threatening condition when core
temperature falls below 95°F
• Can occur even when temperature is above
freezing, if windy, wet, or person is inactive
• Can occur year round
• Death results if untreated
• Occurs rapidly during cold water immersion
Hypothermia (2 of 3)
• Heartbeat, breathing, response to pain
may not be detectable
• Victim can still be alive.
• Check circulation for 30-45 seconds.
• Start CPR immediately if immersion
occurred.
• Handle gently.
• Must be evaluated by physician.
Hypothermia (3 of 3)
• Many different people susceptible.
• Consider when behavior, history, and
weather conditions indicate heat loss.
• More likely if behavior is strange and
victim was shivering.
• Alcohol, medications can contribute
• Very old, very young, and less fit are
more susceptible
Types of Exposure
• Acute
• Heat loss occurs rapidly (6 hours or less)
• Usually in water
• Subacute
• Heat loss over 6-24 hours
• Land or water
• Chronic
• Long-term cooling greater than 24 hours
• Occurs on land
Recognizing Hypothermia
• Suspect in anyone with temperature less than
95°F.
• Change in mental status:
• Disorientation, apathy, changes in
personality
• Shivering
• Cool abdomen
• Low core body temperature (rectal)
Types of Hypothermia
• Mild to severe based on core body temperature
• In severe cases, shivering stops.
• Do not start CPR if:
• Core body temperature less than 60°F
• Chest is frozen.
• Submerged more than 60 minutes
• Lethal injury
• Transport delayed
• Rescuers endangered
Recognizing Mild Hypothermia
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Vigorous, uncontrollable shivering
Grumbling, mumbling, fumbling, stumbling
Cool or cold skin on abdomen, chest or back
Core body temperature above 90°F
Care for Mild Hypothermia
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Get victim out of cold.
Handle gently.
Replace wet clothing with dry clothing.
Cover head.
Cover with vapor barrier.
Keep victim horizontal.
Do not raise legs.
Do not let victim walk or exercise.
Call 9-1-1.
Allow shivering.
Recognizing Severe
Hypothermia
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No shivering
Ice cold, blue skin
Stiff, rigid muscles
Altered mental status, not alert
Slow breathing and pulse
Victim might appear dead
Core body temperature below 90°F
Care for Severe Hypothermia
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Get victim out of cold.
Handle gently.
Replace wet clothing with dry clothing.
Cover head.
Cover with vapor barrier.
Keep victim horizontal.
Do not raise legs.
Do not let victim walk or exercise.
Call 9-1-1.
When remote, warm by any available heat source.
Adding Heat
• Problems with rewarming:
• Warm water immersion requires a lot of
warm water and a bathtub.
• Hot baths can cause cardiac arrest.
• Body-to-body contact in insulated sleeping
bag is ineffective.
• Use body-to-body rewarming only when
delayed care or other methods unavailable.
• Chemical heating pads are not effective.
Dehydration
• In cold weather, fluid is lost through exhaled
breath.
• Color and volume of urine indicate
hydration.
• Unmelted snow and ice should not be
consumed; can lower body temperature.
• If snow, ice are only available sources of
water, melt before consuming.
• Melted snow, ice should be disinfected
before drinking.