Hypothermia

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 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.

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. 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.

12. 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. 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. 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. 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. 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. 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. 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.