Chapter 20Cold-Related Emergencies

Cold-Related Emergencies

• When surrounded by air or water cooler than body temperature, the body experiences heat loss.− Normal body temperature is 98.6F.

• If body temperature falls much below that, cold injuries can result.

How Cold Affects the Body

• The body has two internal mechanisms to maintain body temperature.− Vasoconstriction

• Tightening of blood vessels− Shivering

• Stops when core temperature falls between 86F and 90F

How Cold Affects the Body

• Physical activity produces heat.− Heat loss increases if clothes become wet

with sweat.• Susceptibility can be minimized by:

− Proper hydration and nutrition− Avoiding alcohol, caffeine, and nicotine− Limiting periods of inactivity

How Cold Affects the Body

• The colder the temperature, the greater the potential for body heat to escape.− The brain signals blood vessels in skin to

tighten, and blood flow to skin decreases.− Because of reduced blood flow to skin, skin

temperature falls.

How Cold Affects the Body

• When exposure lasts more than an hour:− Sensation, touch, and pain will be blunted.− Dexterity and agility will be lost.− A person’s ability to perform manual tasks will

be impaired.

Heat Loss From the Body

• Normal body temperature is maintained by a balance of heat production and heat loss.

• Shivering increases heat production.− Rapidly consumes calories stored as glycogen.− Lack of food limits ability to produce heat.− When glycogen stores are depleted, heat

output decreases.

Heat Loss From the Body

• Four mechanisms of heat loss− Conduction− Convection− Evaporation− Radiation

© Jones & Bartlett Learning.

Susceptibility to Cold Injury

• Physically unfit• Dehydration• Very lean people• Older people• Alcohol, caffeine

• Nicotine• Inadequate

nutrition, illness, injury

• Previous cold injury

Effects of Altitude

• Air temperature drops 3.6F every 1,000 feet.

• Winds are more severe.• Frostbite is more common above 8,000

feet.

Effects of Water

• Water conducts heat away from the body.• Plunging into cold water can cause:

− Irregular heartbeat− Gasping, hyperventilation− Inhalation of water− Heart failure− Drowning

Effects of Wind

• Wind increases heat loss from skin exposed to cold air.

• Windchill is the combined effect of the ambient temperature and wind speed.

Effects of Metal and Liquid Fuels

• Can conduct heat away from skin rapidly• Contact can cause nearly instantaneous

freezing.

Minimizing Effects of Cold on the Body

• First layer− Removes perspiration

• Middle layer− Insulates

• First layer− Protects against wind

© Simon Price/Alamy.

Nonfreezing Cold Injuries

• Can occur when conditions are cold and wet, and hands and feet cannot be kept warm and dry

Chilblain

• Painful• Causes little or no permanent damage• Can develop in 3 to 6 hours

Chilblain: What to Look For

• Swollen skin• Skin that is tender, hot to the touch, and

possibly itchy• Blisters• Aching, prickly sensation, numbness

Chilblain: What to Do

• Get person out of cold.

Trench Foot

• Develops when skin on feet is exposed to moisture and cold for 12 hours or longer

• Caused by:− Wearing wet boots and shoes− Prolonged immersion of feet in cold water

• Cold and moisture soften skin, causing tissue loss and infection.

Trench Foot: What to Look For

• Itching, numbness, tingling pain• Swollen feet and pale skin cold to touch• Red or blue blotches on the skin

− Sometimes open weeping or bleeding

Trench Foot: What to Do

• Dry the skin.• Rewarm foot gradually.• Care for open weeping areas.

− Use mild soap and water.− Apply a breathable dressing.

Freezing Cold Injuries

• Occur whenever air temperature is below freezing− Frostnip

• Freezing is limited to skin surface.− Frostbite

• Freezing extends into the flesh.

Frostnip

• Frostnip is caused when water on the skin surface freezes.

Courtesy of Neil Malcom Winkelmann.

Frostnip: What to Look For

• Yellow to gray skin color• Frost on the skin• Initial tingling or numbness that may

become painful

Frostnip: What to Do

• Get the person out of the cold.• Gently warm affected area.• Do not rub the affected area.

Frostbite

• Two ways of damage− Tissue freezing− Obstruction of blood

supply to the tissue• Affects feet, hands,

ears, and nose© American Academy of Orthopaedic Surgeons.

Frostbite: What to Look For (Before Thawing)

• Superficial frostbite− White, waxy, or grayish yellow skin− Part feels cold and numb.− Tingling, stinging, aching− Stiff or crusty skin− Underlying tissue is soft.

Frostbite: What to Look For (Before Thawing)

• Deep frostbite− Part feels cold, hard, and solid and cannot be

depressed.− Pale, waxy skin− Painfully cold part stops hurting.

Frostbite: What to Do (Before Thawing)

• Get person to warm area.• Remove wet clothing and constricting items.• Do not attempt to thaw the part if:

− Medical care is less than 2 hours away.− The affected area has thawed.− Shelter, warm water, and a container are not

available.− Risk of refreezing exists.

Frostbite: What to Do (Before Thawing)

• Use the wet, rapid rewarming method if:− Medical care is more than 2 hours away.− No possibility of refreezing− Shelter, warm water, and a container are

available.• If the wet, rapid rewarming method is not

possible, slow rewarming can be done.

Wet, Rapid, Rewarming Method

• Place part in warm water.• Maintain water temperature.• Usually takes 20 to 40 minutes• Air dry the area; do not rub.• Give pain medication.• Apply warm cloths to ear or facial injuries.

Frostbite: What to Look For (After Thawing)

• First-degree− Warm, swollen, and

tender• Second-degree

− Blisters form.• Enlarge over

several days

• Third-degree− Small blisters with

red-blue or purple fluid

− Red or blue skin− Might not blanch

Frostbite: What to Do (After Thawing)

• For feet, do not allow person to walk.• Protect area from contact.• Place dry gauze between toes and fingers.• Slightly elevate affected part.• Apply aloe vera gel.• Provide pain medication and give fluids.• Seek medical care.

Hypothermia

• A life-threatening condition in which the body’s core temperature falls below 95°F

• Heartbeat/breathing may be undetected.• Consider whenever person’s behavior and

history and the weather conditions indicate abnormal heat loss

Types of Cold Exposure

• Acute− Usually in water− 6 hours or less

• Subacute− 6 to 24 hours− Land or water

• Chronic− Occurs on land− Exceeds 24 hours

Hypothermia Symptoms

• Change in mental status• Shivering• Cool abdomen• Low core body temperature

Difference Between Mild and Severe Hypothermia

• Based on core body temperature• In severe cases, shivering stops.

− Do not start CPR if:• Core body temperature is below 60°F.• Chest is frozen.• Submerged in water for more than 60 minutes• A lethal injury exists.• Transport will be delayed.• Rescuers are endangered.

CPR and Severe Hypothermia

• Do not start until after you have checked person’s circulation for 1 minute.

• f no detectible pulse after 1 minute, start CPR.

• CPR can be delayed, given intermittently, or given for several hours.

Mild Hypothermia: What to Look For

• Vigorous, uncontrolled shivering• The “umbles”• Cool or cold skin on abdomen, chest, or

back• Core body temperature above 90°F

Mild Hypothermia: What to Do

• Stop further heat loss.• Apply heat to the chest, armpits, and back.• Warm lower arms and legs in 107°F to

113°F water.• Give warm, sugary drinks.

Severe Hypothermia: What to Look For

• Rigid and stiff muscles• No shivering• Skin feels ice cold and appears blue.• Altered mental status—not alert• Slow heart rate and breathing rate• The person may appear to be dead.

Severe Hypothermia: What to Do

• Follow steps for treating hypothermia.• Cut off the person’s wet clothing.• Monitor breathing; give CPR if necessary.• Call 9-1-1.• Check heart rate for 1 minute before

starting CPR.• Provide rewarming.

Adding Heat

• Problems with rewarming:− Warm water immersion requires a lot of warm

water and a bathtub.− Body-to-body contact in insulated sleeping

bag is not better than shivering.− No evidence that chemical heating pads are

capable of rewarming a hypothermic person.

Dehydration

• Occurs because of unperceived fluid loss combined with inadequate fluid intake

• Cold weather: fluid lost through breath− Drink even if not thirsty.− Monitor color and volume of urine.− Do not consume unmelted snow and ice.