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Unformatted text preview: Ch. 25Heat and Cold Ch. 25Heat and Cold Emergencies How the Body Loses Heat How the Body Loses Heat
1. Radiation, whereby heat is transferred from the surface of one object to the surface of another without actual contact; radiation is the primary way the body loses heat. 2. Conduction, whereby heat is transferred from the surface of one object to the surface of another through direct contact; heat loss through conduction can be 25 times greater in cold air than in cold water. 3. Convection, whereby cold air in immediate contact with the skin is warmed by the skin; heated molecules move away, cooler ones take their place, and the cycle repeats itself. 4. Evaporation, whereby body heat causes perspiration, which is lost from the body surface when it is changed to vapor; twothirds of evaporative loss is through perspiration. 5. Respiration, whereby body heat loses through breathing; onethird of evaporative loss is through respiration. How the Body Conserves Heat How the Body Conserves Heat 1. Blood vessels constrict, keeping the warm blood in the core of the body 2. Hairs stand erect, trapping warm air immediately next to the skin 3. Little or no perspiration is released to the skin surface for evaporation HeatRelated Injuries HeatRelated Injuries
Most susceptible are Athletes Workers near furnaces or ovens Those in poor physical condition Alcoholics The obese The chronically ill Those who have not adjusted to the environment Those with heart disease People using certain drugs (such as diuretics) Burn victims The elderly Children Heatstroke Heatstroke Also called sunstroke A lifethreatening emergency caused by a disturbance in the body’s temperature regulation mechanism, characterized by extreme fever, hot and dry or moist skin, delirium, or coma Heatstroke Heatstroke Body temperature of 105°F or more Hot, red skin that is moist or dry Initially rapid, strong pulse Later rapid, weak pulse Initially constricted pupils Later dilated pupils Tremors Mental confusion or anxiety Irritability or aggression Initially deep, rapid breathing Later shallow, weak breathing Headache Dry mouth Shortness of breath Loss of appetite Nausea and vomiting Dizziness and weakness Seizures or sudden collapse First Aid Care First Aid Care
1. Establish an airway and, when possible, remove the victim from the source of heat. 2. Remove as much of the victim’s clothing as possible, down to his or her underwear; then use a combination of methods to cool the victim until his or her mental status returns to normal. 3. Never give the victim stimulants or hot drinks. 4. As the body cools, seizures or vomiting may occur. Position the victim to allow for easy drainage. 5. Monitor the victim’s temperature while you wait for emergency personnel to arrive. If the temperature starts to climb, start cooling procedures again. (The temperature must drop below 102°F and must stay that low before the danger has passed.) Cooling Techniques Cooling Techniques Ice packs under arms, in the groin, around the neck, behind the knee, and around ankles Spray or pour cool water on the victim Place them in tub of cool water Alternating wet towels Fans *Never use isopropyl alcohol* Cooling Techniques Heat Exhaustion Heat Exhaustion A heatrelated emergency caused by excessive loss of water and salt through sweating, characterized by cool, clammy skin and a weak, rapid pulse Heat Exhaustion Signs & Heat Exhaustion Signs & Symptoms Headache Weakness/Fatigue Nausea/vomiting Diarrhea Loss of appetite Dilated pupils Dizziness/fainting Profuse Sweating Pale, cool, ashen skin Near normal temp Muscle Cramps Heat Exhaustion Heat Exhaustion 1. Move the victim to a cool place, remove as much of the victim’s clothing as possible, and fan the victim lightly. Make sure the victim does not get chilled or begin to shiver. 2. Have the victim lie down, raise the feet 8 to 12 inches. 3. If the victim is fully conscious, give him or her cool water or commercial sports drink to drink at the rate of half a glass every 10 minutes for 1 hour. Never give the victim salt tablets. If the victim is nauseated or vomits, stop giving fluids and activate the EMS system immediately. 4. If the victim is unconscious, immediately activate EMS, and manage the airway and ventilation. 5. Take the victim’s temperature every 10 to 15 minutes. When to Activate EMS When to Activate EMS
If the temperature is above 101°F or is rising If the victim is unable to drink fluids or vomits after drinking fluids If the victim does not improve Heat Cramps Heat Cramps Muscle spasms caused by a disturbance in the electrolyte balance of the muscles Usually occur when the body loses too much salt and/or other electrolytes during profuse sweating Heat Cramps Heat Cramps
1. If the victim is in a hot environment, remove him or her from the heat immediately; have the victim rest in a cool place. 2. Administer sips of water or a sports drink at the rate of half a glass every 15 minutes. 3. Apply moist towels to the victim’s forehead and over the cramping muscles. To relieve pain, try gently stretching the involved muscle groups. 4. Explain to the victim what happened and why so the victim can avoid a recurrence; the victim should avoid exertion of any kind for at least 12 hours, or heat cramps will recur. Activate the EMS system if the victim has other illnesses or injuries, if other symptoms develop, or if the victim’s condition worsens or does not respond to care. Cold Related Injuries Cold Related Injuries
Types: General hypothermia Immersion hypothermia Frostbite *Can occur at any time of year* Hypothermia Hypothermia Condition in which an organism's temperature drops below that required for normal metabolism and bodily functions. When the body is exposed to cold its internal mechanisms may be unable to replenish the heat that is being lost to the organism's surroundings. 800 Americans die each year from hypothermia First 30 minutes of care are critical to survival Contributing Factors Contributing Factors
Factors contributing to hypothermia, even in the absence of cold environment, include Certain drugs (i.e., central nervous system depressants) Surgery Water activities Existing disease Trauma Massive blood loss Extremes of age (very young or very old) Immobility Stages of Hypothermia Stages of Hypothermia Stage 1: lose 1.83.6°F; Shivering Stage 2: lose 3.67.2°F; Apathy and decreased mental function Stage 3: temperature below 89.6°F; Decreased level of consciousness Stage 4: Decreased vital signs Stage 5: Death Skin that is cold to the touch (To test, place the back of your hand against the skin of the victim’s abdomen.) Uncontrollable shivering Vague, slurred, thick speech Amnesia and incoherence Disorientation, confusion Poor judgment Staggering gait Dizziness Pale, cold, waxen skin Stiff and hard muscles Sluggish pupils Increased heart and respiratory rates (early) Decreased heart and respiratory rates (late) Dehydration Drowsiness and/or stupor Apparent exhaustion Unconsciousness Signs and Symptoms of Signs and Symptoms of Hypothermia 1. Check the victim’s vital signs. Measure for 1 full minute, because vital signs are slowed and weak in hypothermia. If there is no pulse, open the airway and begin CPR. If an AED is available, deliver only one shock. If that does not correct the rhythm, continue CPR and do not deliver any additional shocks. 2. Handle the victim very gently. Don’t let the victim walk around or move much on his or her own. 3. Keep the victim in a supine position to prevent shock and increase blood flow to the brain. Do not elevate the legs; doing so causes cold blood to flow to the heart. 4. Prevent further heat loss 5. Never rub or manipulate the arms or legs; you could force cold blood from the veins into the core circulation and heart, causing abnormal heart rhythm or cardiac arrest. 6. Never give the victim tobacco, coffee, or alcohol. Give warm fluids only after uncontrollable shivering stops and the victim is completely conscious. First Aid Care for First Aid Care for Hypothermia First Aid Care for Severe First Aid Care for Severe Hypothermia
1. Never try to rewarm a severely hypothermic victim. Insulate the victim against further heat loss, but do not apply any source of heat. Handle the victim extremely gently. 2. Assess vital signs over a 2minute period; if there is no heartbeat during the 2 minutes, start CPR. 3. Maintain airway, breathing, and circulation until EMS arrives. Immersion Hypothermia Immersion Hypothermia
Body temperature drops to water temperature within 10 minutes Effected by: Water temperature Body size Clothing Physical activity BAC First Aid for Immersion First Aid for Immersion Hypothermia
1. Activate the EMS system immediately. 2. Maintain the victim’s airway, breathing, and circulation. 3. Keep the victim still and quiet; the coldest blood is in the extremities, and it will circulate rapidly to the heart with movement. 4. Follow insulating and rewarming guidelines as for general hypothermia, remembering to handle the victim very gently. Frostbite Frostbite
Frostbite is the freezing of body tissue (Frostnip is the freezing of the skin surface) Commonly affects hands, feet, ears, nose, and checks Occurs when ice crystals form between the cells of the skin Temperature of skin must be below freezing Skin may be red and painful or white and waxy Frostbite Frostbite Likelihood of frostbite is increased by: Trauma Blood loss Tight footwear BAC Wet clothing High altitudes Race Age Degrees of Frostbite Degrees of Frostbite First Degree: affects tips of ears, nose, cheeks, fingers, toes, chin; skin is blanched, white and painless Second Degree: affects skin and tissue just below the skin; skin is firm and waxy, tissue is soft and numb, then turns purple during thawing Third Degree: Affects entire tissue depth; tissue beneath the skin is solid, waxy white with purplish tinge First Aid for Frostbite First Aid for Frostbite First Degree: skin can be warmed by applying firm pressure, blowingwarm breath on the spot or by submerging in warm water Second Degree: Provide dry coverage and steady warmth; submerge in warm water Third Degree: Need immediate medical care. Dry clothing over frostbite will help prevent further injury. Submerge in warm water (100110 degrees F) to rewarm First Aid for Frostbite First Aid for Frostbite
1. Immediately remove the victim from the cold environment. 2. Keep the tissue frozen until you can initiate care; never thaw tissue if there is any chance of its refreezing 3. Protect the injured tissue from friction or pressure; never poke or squeeze the tissue. Remove constricting clothing or jewelry that is not sticking to the skin. 4. Thaw frostbitten tissue in a water bath. 5. Keep rewarming until the skin color no longer improves (re warming to this point may take as long as 40 minutes). 6. Cover the thawed parts with loose, dry, sterile dressings and elevate the extremities. Place sterile gauze between the fingers and toes to reduce the risk of increased injury. 7. While waiting for emergency personnel to arrive, monitor vital signs and keep the victim warm. Do not let the victim walk if the feet are involved, and do not let the victim smoke. Do not reexpose the thawed part to the cold. Considerations Considerations Do not rewarm a part if it may be re frozen Do not thaw a part if the victim must walk on it to reach a medical facility Never rub a frozen or frostbit body part Do not delay EMS care for rewarming Mammalian reflex Questions? Questions? ...
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This note was uploaded on 02/17/2011 for the course HK 280 taught by Professor Trembath during the Fall '07 term at Purdue University-West Lafayette.
- Fall '07