Transcript Hypothermia

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Hypothermia
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Introduction
Dropping temperatures, wind chill, rain, sleet and
snow… Cold weather conditions such as these can
leave you feeling chilled to the bone. If your job
requires you to work in cold conditions, you need to
be able to recognize the conditions that can lead to
hypothermia.
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Introduction
Hypothermia is a temperature related disorder that
occurs when exposure to cold causes a decrease in
your internal temperature so that your normal
muscular and brain functions become impaired.
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Introduction
Your best defense against hypothermia is to be
prepared. Wear the appropriate clothing. Get adequate
food and rest. Avoid smoking, alcohol and caffeine
during exposure to cold. Be able to recognize the
early warning signs of hypothermia, and know what
to do if an emergency occurs.
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What is Hypothermia?
While the average normal human temperature is about
98.6 degrees Fahrenheit, that temperature can vary
slightly from person to person. Your body is capable of
maintaining an internal core temperature between 98.6
and 102.2 degrees Fahrenheit. When the body begins to
lose heat faster than it can produce it, your temperature
begins to fall and hypothermia can occur.
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What is Hypothermia?
Hypothermia is a cold temperature related disorder that
occurs when exposure to cold causes a decrease in the
core (heart, lungs, and other organs) temperature to a
level that leads to impairment of your normal muscular
and brain functions.
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What is Hypothermia?
Generally, hypothermia occurs at a core temperature
of about 95 degrees Fahrenheit or below. In extreme
cases, hypothermia can lead to loss of consciousness,
tissue damage, and even death.
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What is Hypothermia?
This disorder is particularly dangerous because it
affects your brain’s ability to function properly. You
lose your capacity for good judgement, reasoning, and
mental clarity. You may not even be able to recognize
that you have symptoms!
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What is Hypothermia?
Causes of Hypothermia
There are many different variables that can lead to
hypothermia. The primary factors include cold, wind,
and wetness. There are two main types of hypothermia:
cold exposure and water immersion.
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What is Hypothermia?
Cold Exposure - Exposure to cold temperatures is an
important factor in hypothermia, but it is not the only
factor. In fact, most hypothermia cases occur at
temperatures between 30-50 degrees Fahrenheit.
Windchill is also an important factor.
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What is Hypothermia?
For example, if the wind is calm but the temperature is
-30 degrees Fahrenheit, exposed skin may freeze within
one minute. But this may also happen if the wind speed
is 10 MPH and temperature is -10 degrees Fahrenheit.
When wetness is factored in, the effects of cold and
wind are even more chilling.
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What is Hypothermia?
Water Immersion - Hypothermia due to water
immersion, such as falling into a cold lake, is an even
greater danger. The body cools up to 25 times faster in
water than in air. This rapid heat loss speeds up the
hypothermia process and can result in death within
minutes.
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What is Hypothermia?
Contributing Factors
Other factors that can contribute to hypothermia
include:
•Age
•Body Size
•Physical Condition
•Length of Exposure
•Exhaustion
•Hunger
•Dehydration
•Certain illnesses
•Some medications
•Alcohol intake
•Smoking
•Improper clothing and
equipment
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What is Hypothermia?
Time Frame for Hypothermia
It is difficult to identify a specific time frame for the
onset and progression of hypothermia. One person
may develop symptoms faster than another; that
same person may also progress through the stages of
hypothermia much more quickly. There are a few
reasons for this:
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What is Hypothermia?
Time Frame for Hypothermia
•Physical condition and mental attitude can affect the rate
of core temperature drop. A person who is fit, doesn’t
panic, and believes he will survive may experience a
slower drop in core temperature than someone who is not
as physically and psychologically prepared.
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What is Hypothermia?
Time Frame for Hypothermia
•Environmental circumstances vary from one situation to
another. For example, a water temperature of 70 degrees
Fahrenheit drains body heat faster than water at 80
degrees Fahrenheit. An air temperature of 50 degrees
Fahrenheit may be endurable, but with a 25 MPH wind
and humidity it can be chilling.
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How the Body Loses Heat
To better understand how hypothermia occurs, it is
important to know how the body loses heat. There are
five different ways your body can lose heat to its
surroundings:
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How the Body Loses Heat
Respiration
When you breathe cold air into your lungs, it is
warmed to body temperature. You lose heat to the
environment when you exhale the warm air
outside of your lungs. You can reduce the heat loss
by covering your mouth and nose with a scarf or
face mask.
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How the Body Loses Heat
Evaporation
This type of heat loss occurs as the body becomes
hot and you begin to sweat. As the perspiration
reaches the surface and evaporates from the skin, the
body is cooled.
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How the Body Loses Heat
Conduction
Heat loss can also occur when you touch a colder
object. Heat from your body is transferred to that
object. An example would be touching cold
equipment or sitting on the ground.
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How the Body Loses Heat
Radiation
Radiation occurs when heat is radiated outward
from your body to the environment. This can
happen when skin is left uncovered, especially the
head, neck, and hands. Always wear the proper
clothing to prevent excess heat loss from radiation.
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How the Body Loses Heat
Convection
Convection occurs when cool air or water move
across the body. Body heat is transferred to the air
or water, warming it. When the warm air or water
moves away from the body, the body then becomes
cold.
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How the Body Produces Heat
The human body can easily adjust to minor changes in
temperature for short periods by activating its
thermoregulatory system. The thermoregulatory system
is controlled by the brain, spinal cord, and a network of
nerves throughout the body that sense temperature.
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How the Body Produces Heat
The brain monitors the difference between the
core(internal) temperature and the peripheral (skin and
muscles) temperature. Messages are sent to the body’s
two nervous systems: the somatic (voluntary) nervous
system and the autonomic (involuntary) nervous system.
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How the Body Produces Heat
Voluntary Response to Cold
The somatic, or voluntary, nervous system receives
thought patterns that give you specific messages to
prevent heat loss. Examples of these messages might
be to build a fire or put on more clothing. You then
decide if you will carry out those directions.
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How the Body Produces Heat
Involuntary Response to Cold
The automatic, or involuntary, nervous system
controls the body’s internal organs and blood vessels
without our conscious knowledge. For example, if
you fall into an icy pond the heart speeds up and
blood pressure increases. Two examples of how the
body maintains or generates heat include:
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How the Body Produces Heat
Shivering
This is the body’s involuntary contraction and expansion
of muscles to increase heat production through friction.
Reducing Blood Flow
The body reduces blood flow to the skin and limbs
by constricting blood vessels. The purpose is to
reduce heat loss to the core - the brain, heart, lungs,
and other body organs.
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Before Hypothermia Begins
Mild shivering and cold hands and feet do not
necessarily mean you are hypothermic. These are,
however, early warning signs that you are losing
more heat than you are producing. If you ignore
these signs, you will begin to experience the early
stages of hypothermia.
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Before Hypothermia Begins
Early Warning Signs
You may start to feel tired. Your body’s metabolism
increases to produce heat. This is noticed as heavier
breathing and an increased pulse rate. Goose bumps
appear. Goose bumps form to hold the hair follicles
upright. This increases their ability to insulate and
protect the body from cold.
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Before Hypothermia Begins
Early Warning Signs
Shivering begins, on and off, as your body temperature
falls below 97 degrees Fahrenheit. At this point,
shivering can be overcome with an increase in physical
activity.
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Before Hypothermia Begins
Early Warning Signs
The body begins to reduce blood flow to the skin and
limbs to reduce heat loss to the body’s core. Cold,
white hands and feet are the first signs that this is
happening.
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Symptoms of Hypothermia
Hypothermia is generally believed to occur when the
core temperature falls to 95 degrees Fahrenheit or
below. However, it is important to remember that not
all victims experience symptoms at exactly the same
temperatures.
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Symptoms of Hypothermia
The response to cold varies depending on health, age,
type of exposure, and physical fitness. Once
hypothermia begins, the symptoms progress steadily,
from mild to severe unless treatment is received.
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Symptoms of Hypothermia
By identifying the symptoms, you can prevent the
progression and decrease the severity of hypothermia.
Remember, a hypothermia victim may not realize
what is happening.
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Symptoms of Hypothermia
Ignore any pleas to “leave me alone, I’m okay.”
Because hypothermia affects the capacity for good
judgement and mental clarity, you cannot rely on what
a victim tells you. Pay attention to the symptoms!
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Symptoms of Hypothermia
Mild Hypothermia
At this stage, the victim may appear alert and able to
help himself or herself, but he or she is experiencing
some mild confusion. Restricted blood flow to the
limbs causes a loss of dexterity in the fingers.
Symptoms include:
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Symptoms of Hypothermia
•Uncontrolled, violent shivering
•Pain and discomfort in exposed parts
•Muscles become tense
•Skin may be pale, numb, and waxy
•Unable to perform complex tasks with hands (such as
buttoning your coat)
•Poor muscle coordination
•Tendency to stumble
•Movements become slower and less coordinated
•Difficulty in speech
•Mild confusion; victim may appear dazed
•Tendency to become uncooperative or irritable
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Symptoms of Hypothermia
Severe Hypothermia
Severe hypothermia is generally believed to begin
when the core temperature falls to about 91.4 degrees
Fahrenheit. This stage includes conscious victims who
experience slurred speech, mental confusion and
drowsiness to victims who may appear dead but are
still alive. Symptoms can include:
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Symptoms of Hypothermia
•Mental confusion
•May show signs of apathy or depression
•Speech is slow, slurred, or vague
•Drowsiness or an overpowering desire to sleep
•Sluggish thinking
•Signs of strange irrational behavior, such as undressing
•Shivering slows and stops at about 90 degrees Fahrenheit
•Muscles become rigid
•Fixed and dilated pupils
•Pulse rate slows significantly
•Breathing slows, is shallow and erratic
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Symptoms of Hypothermia
•Cold, blue skin
•Eventually victim is unable to walk and may curl up in the
fetal position to conserve heat.
•Between 89.6 and 87.8 degrees Fahrenheit the victim can
become semi-comatose.
•Risk of ventricular fibrillation (irregular heartbeat)
increases.
•At about 86 degrees Fahrenheit the victim can sink into a
“metabolic icebox” state. You may not be able to determine
a pulse, and the victim may appear to be dead.
•Eventually, cardiac arrest can occur.
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Treatment
The treatment for hypothermia depends on the
patient’s condition. Mildly hypothermic victims
who are conscious usually re-warm without
complications once they are removed from the cold.
However, victims of severe hypothermia who are
unconscious often give no indications of being
alive, but still may have vital signs.
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Treatment
Never assume that an unconscious victim is dead;
the vital signs may be so weak that you will not be
able to detect them, but the person can still be alive.
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Treatment
Mild Hypothermia
•Encourage light physical activity to generate heat, such as
moving the arms and legs or walking.
•Get the victim out of the elements to a dry, sheltered area.
•Remove any wet clothing and replace with dry layers.
•Wrap the person in a blanket. Make sure the head and
neck are also covered.
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Treatment
Mild Hypothermia
•Apply warm (NOT hot) hot pads, hot water bottles, or
other objects behind the patients neck and under the
armpits.
•Provide a warm (about 110 degrees Fahrenheit) nonalcoholic, caffeine-free drink and some high energy food.
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Treatment
Severe Hypothermia
It is always best to let the hospital re-warm a severely
hypothermic person. But in some cases you may not
have immediate access to a medical facility. In these
situations, there are some steps you can take to
prevent further heat loss before medical treatment can
be received.
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Treatment
Severe Hypothermia
•If the victim is semi-conscious, try to keep him or her
awake.
•Unconscious victims should be taken to the hospital for
treatment as soon as possible. Hospitals have specialized
equipment that can detect vital signs, properly monitor the
person, and control the re-warming process.
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Treatment
Severe Hypothermia
•Handle the victim as gently as possible. Rough handling, in
extreme cases, can cause cardiac arrest. Keep the patient in
a horizontal position.
•Remove any wet clothing.
•Apply warm (NOT hot) heat packs or towels to the neck,
armpits, sides, chest, and groin.
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Treatment
Severe Hypothermia
•Do not try to re-warm the patient in a hurry.
•Place the victim in blankets (or a sleeping bag, if
available), making sure the blankets are under as well as
over the victim. Keep the head and neck covered.
•Exhale warm air near the person’s nose or mouth.
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Treatment
Severe Hypothermia
•Do NOT warm or rub the victim’s arms or legs. This may
bring cold blood from the body’s surface to the core (heart
and lungs) and can cause a cardiac arrest.
•Do not give a victim of severe hypothermia who is
semiconscious any liquids.
•Do NOT begin CPR unless you are absolutely sure the
victim is in a state of cardiac arrest.
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Prevention
The best prevention against hypothermia is to be
prepared. Your main goal is to prevent fatigue
while remaining warm and dry.
Clothing
To dress properly for cold conditions, you need to
understand that the higher the wind speed and the
lower the temperatures, the greater danger to
exposed skin. For example, if the temperature is
-30 degrees Fahrenheit with no wind, exposed skin
may freeze within one minute.
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Prevention
Clothing
This could also happen if the temperature is -10
degrees Fahrenheit with a wind speed of 10 MPH.
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Prevention
•Wear several layers of clothing, rather than one bulky
layer, so you can remove a layer when you become to warm.
The layer closest to your skin should be made of material
that allows sweat to escape while keeping out
environmental moisture.
•Synthetic materials such as polypropylene and Gortex are
good for this (cotton traps moisture). Wool is a good choice
for the second layer because it can absorb much moisture
before it loses its ability to insulate. Wear waterproof, wind
resistant clothing for the outer layer if you will be in wet
conditions.
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Prevention
•Do not wear clothing that is tight or constricts your
movements.
•Hands and feet are affected most during cold conditions.
Wear well insulated gloves, mittens and boots. Wear two
layers of socks: a synthetic material under wool.
•Always keep your head and neck covered. Up to 50
percent of heat loss occurs through the head and neck! A
wool knit cap or a liner under a hard hat can greatly
reduce heat loss.
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Prevention
Keep Dry
•Wet clothing increases heat loss. Replace wet layers as
soon as possible. In very cold temperatures, changing
clothes can increase heat loss, so be careful. If you can’t
change clothes indoors, the it may be better to just put on
more clothes on top of those you are already wearing.
•If possible, always bring an extra set of clothing with you
in case your clothes become wet.
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Prevention
Food, Fluids & Fitness
•Eat balanced meals with plenty of carbohydrates and
drink plenty of fluids (non-alcoholic and caffeine-free) to
prevent dehydration.
•Avoid caffeine in cold weather. Caffeine is a diuretic; it
causes increased urine production, which leads to increased
heat loss. It also causes dehydration.
•Avoid alcohol in cold weather. A common mistaken belief
is that alcohol will keep you warm in cold weather. That is
NOT true. Alcohol dilates the blood vessels and causes
blood to move away from the body’s core.
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Prevention
Food, Fluids & Fitness
•Avoid nicotine and tobacco. They cause the blood vessels
to constrict, increasing the risk of frostbite.
•Physical fitness and regular exercise can improve your
tolerance to cold conditions.
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Prevention
Frequent Breaks
•If you will be working in a cold environment, take
frequent breaks to provide relief from the cold, and when
you experience uncontrolled shivering, increased
perspiration, or feel numbness or pain in the extremities.
Know your physical limits.
Buddy System
•Always try to work in pairs and rely on the “buddy
system” in cold environment. Be aware of any possible
warning signs of hypothermia in your co-worker. If you
notice any, get him or her indoors as soon as possible to
warm up.
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Prevention
Cold Water Survival
•Always wear a personal floatation device (PFD) when you
will be on the water. If you fall into cold water, the PFD will
help keep you afloat, allowing you to conserve some of your
energy.
•Water safety experts recommend that persons in
dangerously cold water should not swim or move around
any more than necessary. Swimming and treading water
consumes more energy, causes fatigue, and increases heat
loss.
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Prevention
Cold Water Survival
•One position to use when in cold water is to draw your
knees up, keeping your thighs together, and crossing your
ankles. Keep your arms crossed close to your chest. This
position reduces heat loss.
•Try to keep your head out of the water as much as possible
to prevent further heat loss.
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