Chapter 20

Cold-Related Emergencies

Cold-Related Emergencies

• When surrounded by air or water cooler than body temperature, body loses heat.• Normal body temperature is 98.6°F.

• If heat escapes faster than the body produces it, the body temperature falls, and cold injuries result.

How Cold Affects the Body (1 of 2)

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

• Vasoconstriction• Tightening of blood vessels• Can cause discomfort, numbness, loss of

dexterity, cold injuries• Shivering

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

How Cold Affects the Body (2 of 2)

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

with perspiration.• Susceptibility can be minimized by:

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

Heat Loss from the Body (1 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

Heat Loss from the Body (2 of 2)

• Four mechanisms of heat loss (cont’d):• Radiation

• Heat given off to cooler air

• Accounts for the greatest heat loss

Susceptibility to Cold Injury• Physically unfit• Dehydration• Very lean people• Elderly people• Alcohol, caffeine• Nicotine• Inadequate nutrition, illness, injury• Experienced a previous cold injury

Effects of Altitude• Air temperature drops 3.6°F

every 1,000 feet.• Winds are more severe.• More susceptible to frostbite

above 8,000 feet

Effects of Water• Water can conduct heat away from

the body much faster than air of the same temperature.

• Wet clothing accelerates heat loss.

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 almost instantaneous freezing

Minimizing Effects of Cold on the Body (1 of 2)

•Layering• Undergarment

removes perspiration• Wicking

properties

© Simon Price/Alamy Images

Minimizing Effects of Cold on the Body (2 of 2)

• Middle layer insulates.• Should be effective when wet.• Synthetics are better than natural fibers. • Wool

• Outer layer protects against wind.• Waterproof• Wind resistant• “Breathable” • Hat

Nonfreezing Cold Injuries• Can occur when conditions

are cold and wet and hands and feet cannot be kept warm and dry

Chilblain

• Is painful• Causes little or no

permanent damage• Can develop in 3 to 6 hours

Recognizing Chilblain• Swollen skin• Skin is tender, hot to the

touch, and possibly itchy. • Blisters• Aching, prickly sensation,

numbness

Care for Chilblain

• Get victim out of cold.

Trench Foot• Develops when skin on the feet is exposed to

moisture and cold for 12 hours or longer. • Caused by:

• Wearing wet boots and shoes• Prolonged immersion of the feet in cold

water• Rubberized or tight-fitting boots increase risk.

Recognizing Trench Foot and Immersion Foot

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

• Sometimes open weeping or bleeding

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

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

Freezing Cold Injuries• Occur when 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

Recognizing Frostnip

• Red and sometimes swollen skin

• Painful• Repeated frostnip can dry the

skin.

Care for Frostnip• 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

Recognizing Frostbite (1 of 2)

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

Recognizing Frostbite (2 of 2)

Indications of deep frostbite:•Part feels cold, hard, and solid and cannot be depressed. • Blisters• Pale, waxy skin • Painfully cold part

suddenly stops hurting

Classifications of Frostbite • First-degree

• Warm, swollen, and tender

• Second-degree• Blisters form.• Enlarges over

several days.

• Third-degree• Small blisters with

reddish-blue or purplish fluid

• Red or blue skin• Might not blanch

• Fourth-degree• No blisters or

swelling.• Part remains

numb, cold, and purple.

Care for Frostbite (1 of 2)

• Get victim to warm area.• Remove wet clothing and constricting items.• Seek medical care.• If affected part is partially thawed:

• Place part in warm water. • Maintain water temperature. • 20 to 40 minutes • Give pain medication.• Apply warm cloths to ear or facial injuries.

Care for Frostbite (2 of 2)

• After thawing:• Treat the victim as a stretcher case.• Protect area from contact with clothing and

bedding.• Place dry gauze between toes and fingers.• Slightly elevate the affected part. • Apply aloe vera gel.• Provide pain medication.

Hypothermia• A life-threatening condition in which the

body’s core temperature falls below 95°F• Body loses more heat than it produces.

• Heartbeat/breathing may be undetected• Begin CPR immediately.

• Consider whenever victim’s behavior and history and the weather conditions indicate abnormal heat loss

Types of 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

• Disorientation• Apathy• Changes in personality

• Shivering• Cool abdomen• Low core body temperature

Types of Hypothermia• Mild to severe 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.

Recognizing Mild Hypothermia• Vigorous, uncontrolled shivering• Decreased mental skills• Slurred speech• Difficulty using fingers or hands• Staggers while walking• 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.• Prevent heat loss.• Cover the victim with a vapor barrier.• Keep the victim horizontal.• Call 9-1-1.• Allow the victim to shiver.• Give warm, sugary drinks.

Recognizing Severe Hypothermia

• No shivering• Ice cold and blue skin• Stiff and rigid muscles• Altered mental status• Slow breathing and pulse• Might appear dead.• Core body temperature is below 90°F.

Care for Severe Hypothermia• Get victim out of the cold.• Handle gently.• Prevent heat loss. • Cover with vapor barrier.• Keep victim horizontal.• Call 9-1-1.• When remote, warm by available heat.

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 victim.

Dehydration (1 of 2)

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

• Cold weather: fluid lost through breath• Drink even if not thirsty

• Inactive: drink two quarts of water daily• Color and volume of urine indicate

hydration.

Dehydration (2 of 2)

• Unmelted snow and ice should not be consumed for water.

• Irritates the mouth.• Wastes body heat• Lowers body temperature• Be sure snow and ice are disinfected

before consumption.