Download LESSON 6: BLEEDING AND WOUNDS

Lesson Outline
Chapter 20
Lesson 20: Cold-Related Emergencies
Lesson Objectives
After completing this lesson, participants should be able to:
 Describe how heat is lost from the body.
 Discuss who is susceptible to cold injury.
 Discuss the effects of altitude, water, wind, metals, and liquid fuels.
 Discuss how to minimize the effects of cold on the body.
 Describe nonfreezing cold injuries (chilblain and trench foot) and how they are
cared for.
 Describe freezing cold injuries (frostnip and frostbite) and how they are cared for.
 Discuss hypothermia, types of exposure, and types of hypothermia.
 Describe how mild and severe hypothermia are cared for.
 Discuss disadvantages of various methods for adding heat.
 Discuss the role of dehydration and how to prevent it.
Points
Cold-Related Emergencies
 Normal body temperature is 98.6°F.
 The body loses heat when it is surrounded by air or water that is cooler than the
body.
 The body temperature then falls
 Cold injuries can result
How Cold Affects the Body
 Biologic defense mechanisms protect body
 Vasoconstriction is tightening of the blood vessels.
 The reduced blood flow conserves body heat but can cause discomfort, numbness,
loss of dexterity in the hands and fingers, and eventually, cold injuries.
 Shivering produces body heat.
 Shivering stops when core temperature falls too low or when there is no fuel.
 Physical activity produces heat.
o Heat loss can occur 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 the body’s ability to perform
manual tasks.
Heat Loss From the Body
 Body temperature is maintained by a balance of heat production and loss.
 Shivering rapidly consumes calories.
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Lesson Outline
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Chapter 20
Heat loss occurs primarily through the skin.
Four mechanisms of heat loss:
o Conduction
 Direct contact with colder object
o Convection
 Loss of heat by air blowing over skin
o Evaporation
 Conversion of liquid on skin to vapor
o Radiation
 Heat given off to cooler air
 This is the 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 and windchill are considerations.
 Air temperature drops 3.6°F every 1,000 feet.
 Winds are more severe at high altitudes.
 People are more susceptible to frostbite above 8,000 feet.
Effects of Water
 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, and
hyperventilation.
o These can cause water inhalation, heart failure, drowning.
Effects of Wind
 Wind increases the potential for body heat loss.
 The windchill index integrates wind speed and air temperature.
o Helps estimate risk of cold injury
 Artificial wind such as riding in an open vehicle can increase heat loss.
Effects of Metal and Liquid Fuels
 Metal objects and liquid fuels that have been left outdoors can conduct heat away
from skin rapidly.
 Contact can cause almost instantaneous freezing.
 Must use great care when handling
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Lesson Outline
Chapter 20
Minimizing Effects of Cold on the Body
 Adequate clothing is key.
 Layered clothing helps maintain proper body temperature.
o Undergarments
 Should wick away perspiration
o Middle layer
 Synthetic pile, fleece, or wool
o 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
 Condition can worsen to aching, prickly sensation
 Eventually, numbness
Care for Chilblain
 Get victim out of cold.
Trench Foot
 Serious injury, also called immersion foot
 Develops when feet are exposed to moisture and cold for 12 hours or longer.
 Moisture softens skin, tissue loss and infection can occur.
 Crippling injury can occur.
Recognizing Trench Foot
 Itching, numbness, tingling pain
 Swollen feet, pale skin that is cold to the touch
 Red, bluish blotches on skin
 Sometimes open weeping, bleeding
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Lesson Outline
Chapter 20
Care for Trench Foot
 Dry the skin.
 Rewarm the foot gradually.
 Cleanse weeping areas with mild soap and water, and apply breathable dressings.
Freezing Cold Injuries
 Freezing cold injuries occur when the air temperature is below freezing (32°F).
 Frostnip
o Freezing is limited to skin surface.
 Frostbite
o Freezing occurs deeper in skin.
 Frostbite more common in military situations, mountain climbers, and explorers.
Frostnip
 Water freezes on the skin’s 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
o Place against warm body part
o Blow warm air on area
o After, area can become red and tingling
 Do not rub.
Frostbite
 Frostbite occurs when temperatures drop below freezing
 Tissue can actually freeze.
 Blood supply obstructed
 Affects feet, hands, ears, nose
 The most severe consequence is gangrene (dead tissue).
Recognizing Frostbite
 White, waxy, or grayish yellow skin
 Cold and numb
 Tingling, stinging, aching
 Stiff or crusty surface, soft underneath
 Deep frostbite:
o Cold, hard, solid
o Blistering
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Lesson Outline
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Chapter 20
o Cold, pale, waxy skin
o Pain stops
Types of frostbite:
o First-degree: Warm, swollen, tender
o Second-degree: Blisters minutes to hours after thawing, enlarge over
several days
o Third-degree: Small blisters, reddish blue/purplish fluid
o Fourth-degree: No blisters, no swelling. Numb, cold, white to dark purple
Care for Frostbite
 Get the victim to a warm area.
 Remove wet clothing.
 Remove items that could impair circulation.
 Seek medical care.
 If the affected part is partially thawed or the victim is in a remote or wilderness
situation:
o Place the part in warm water.
o Add more warm water to maintain the water temperature.
o Rewarming usually takes 20 to 40 minutes or until the tissues are soft.
 Give aspirin (to adults only) or ibuprofen to reduce pain while rewarming.
 For ear or facial injuries, apply warm, moist cloths, changing them frequently.
 After thawing:
o Place the victim on a stretcher if his or her feet are affected.
o Protect the area from contact with clothing, bedding.
o Place dry dressings between the toes and fingers.
o Slightly elevate the affected part to reduce pain and swelling.
o Apply aloe vera gel to promote skin healing.
o Provide aspirin (adults), or ibuprofen, or acetaminophen.
Hypothermia
 Hypothermia is a life-threatening condition that occurs when the body’s 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.
 Heartbeat, breathing, and response to pain may not be detectable, but the victim
can still be alive.
 Check circulation for 30-45 seconds, rather than the usual 10 seconds.
 Start CPR immediately if immersion occurred.
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Lesson Outline
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Chapter 20
Handle the victim gently.
o Rough handling can cause life-threatening disruptions in the heart rate.
The victim must be evaluated by a physician.
Many different people susceptible, including people who have been outdoors,
accident victims, urban dwellers, elderly people, lightly clad persons, and anyone
who has been immersed in cool or cold water.
Consider hypothermia when the victim’s behavior, history, and weather
conditions indicate heat loss.
More likely if behavior is strange and victim was shivering.
Alcohol and certain medications can contribute.
The very old, very young, and less fit are more susceptible.
Types of Exposure
 Acute
o Heat loss occurs rapidly (6 hours or less)
o Usually in water
 Subacute
o Heat loss over 6-24 hours
o Land or water
 Chronic
o Long-term cooling greater than 24 hours
o Occurs on land
Recognizing Hypothermia
 Suspect hypothermia in anyone with temperature less than 95°F.
 Change in mental status
o Disorientation, apathy, changes in personality
 Shivering
 Cool abdomen
 Low core body temperature (rectal).
o It may not be practical or possible to take a rectal temperature.
Types of Hypothermia
 Hypothermia can be mild to severe based on core body temperature
 In severe cases, shivering stops.
 Do not start CPR if:
o Core body temperature less than 60°F
o The chest is frozen.
o The victim was submerged for more than 60 minutes
o The victim has a lethal injury
o Transport is delayed
o Rescuers are endangered
Recognizing Mild Hypothermia
 Vigorous, uncontrollable shivering
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Lesson Outline
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Chapter 20
Grumbling, mumbling, fumbling, stumbling
Cool or cold skin on abdomen, chest or back
Core body temperature above 90°F
Care for Mild Hypothermia
 Get the victim out of the cold.
 Handle gently.
 Replace wet clothing with dry clothing.
 Cover the head.
 Cover the victim with a vapor barrier.
 Keep the victim horizontal.
 Do not raise the victim’s legs.
 Do not let the 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 the victim out of cold.
 Handle gently.
 Replace wet clothing with dry clothing.
 Cover the head.
 Cover with a vapor barrier.
 Keep the victim horizontal.
 Do not raise the victim’s legs.
 Do not let the victim walk or exercise.
 Call 9-1-1.
 When remote, warm the victim by any available external heat source.
Adding Heat
 Problems with rewarming:
o Warm water immersion requires a lot of warm water and a bathtub.
o Hot baths can cause cardiac arrest.
 Body-to-body contact in an insulated sleeping bag is ineffective.
 Use body-to-body rewarming only when there will be a long delay in getting to
care or other methods unavailable.
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Lesson Outline
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Chapter 20
Chemical heating pads are not effective in a hypothermic patient.
Dehydration
 In cold weather, fluid is lost through exhaled breath.
 The color and volume of urine indicate hydration.
 Unmelted snow and ice should not be consumed; these can lower body
temperature.
 When snow and ice are the only available sources of water, they should be melted
before being consumed.
 Melted snow and ice should be disinfected by boiling, filtering, or using
chemicals, before drinking.
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