2. Hypothermia

3. 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.

4. 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.

5. 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.

6. 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 degrees Fahrenheit. When the body begins to lose heat faster than it can produce it, your temperature begins to fall and hypothermia can occur.

7. 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.

8. 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.

9. 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!

10. 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.

11. Windchill is also an important factor.
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 degrees Fahrenheit.
Windchill is also an important factor.

12. For example, if the wind is calm but the temperature is
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.

13. 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.

14. Other factors that can contribute to hypothermia include:
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

15. Time Frame for Hypothermia
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:

16. Time Frame for Hypothermia
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.

17. Time Frame for Hypothermia
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.

18. 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:

19. 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.

20. 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.

21. 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.

22. 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.

23. 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.

24. 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.

25. 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.

26. 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.

27. 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:

28. 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.

29. 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.

30. 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.

31. 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.

32. 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.

33. 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.

34. 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.

35. 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.

36. 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!

37. 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:

38. 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

39. 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:

40. 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

41. 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.

42. 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.

43. 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.

44. 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.

45. 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) non-alcoholic, caffeine-free drink and some high energy food.

46. 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.

47. If the victim is semi-conscious, try to keep him or her awake.
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.

48. Remove any wet clothing.
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.

49. 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.

50. 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.

51. 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.

52. Prevention
Clothing
This could also happen if the temperature is -10 degrees Fahrenheit with a wind speed of 10 MPH.

53. 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.

54. Do not wear clothing that is tight or constricts your movements.
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.

55. 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.

56. 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.

57. 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.

58. Prevention Frequent Breaks Buddy System
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.

59. 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.

60. 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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