Chapter 20 Cold-Related Emergencies. Normal body temperature is 98.6°F. Body loses heat when...

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• 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

• 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

• 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)

• 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)

• 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

• 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• 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

• 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• 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.