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Ch. 25-Heat and ColdCh. 25-Heat and ColdEmergenciesEmergencies

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How the Body Loses HeatHow the Body Loses Heat

1. 1. RadiationRadiation, whereby heat is transferred from the surface of , whereby heat is transferred from the surface of one object to the surface of another without actual contact; one object to the surface of another without actual contact; radiation is the primary way the body loses heat.radiation is the primary way the body loses heat.

2. 2. ConductionConduction, whereby heat is transferred from the surface , whereby heat is transferred from the surface of one object to the surface of another through direct of one object to the surface of another through direct contact; heat loss through conduction can be 25 times contact; heat loss through conduction can be 25 times greater in cold air than in cold water.greater in cold air than in cold water.

3. 3. ConvectionConvection, whereby cold air in immediate contact with the , whereby cold air in immediate contact with the skin is warmed by the skin; heated molecules move away, skin is warmed by the skin; heated molecules move away, cooler ones take their place, and the cycle repeats itself.cooler ones take their place, and the cycle repeats itself.

4. 4. EvaporationEvaporation, whereby body heat causes perspiration, which , whereby body heat causes perspiration, which is lost from the body surface when it is changed to vapor; is lost from the body surface when it is changed to vapor; two-thirds of evaporative loss is through perspiration.two-thirds of evaporative loss is through perspiration.

5. 5. RespirationRespiration, whereby body heat loses through , whereby body heat loses through breathing; one-third of evaporative loss is through breathing; one-third of evaporative loss is through respiration. respiration.

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How the Body Conserves HeatHow the Body Conserves Heat

1. Blood vessels constrict, keeping the 1. Blood vessels constrict, keeping the warm blood in the core of the bodywarm blood in the core of the body

2. Hairs stand erect, trapping warm air 2. Hairs stand erect, trapping warm air immediately next to the skinimmediately next to the skin

3. Little or no perspiration is released to 3. Little or no perspiration is released to the skin surface for evaporationthe skin surface for evaporation

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PROGRESS CHECKPROGRESS CHECK

1. Heat loss through radiation involves the transfer of heat 1. Heat loss through radiation involves the transfer of heat from the body to another surface without _________. from the body to another surface without _________. (interference/direct contact/evaporation)(interference/direct contact/evaporation)

2. Convection, central to the concept of windchill, occurs 2. Convection, central to the concept of windchill, occurs when air molecules surrounding the skin get ___________, when air molecules surrounding the skin get ___________, rise, and are replaced by cooler air. rise, and are replaced by cooler air. (moved by the (moved by the wind/caught in a draft/warmed by the skin)wind/caught in a draft/warmed by the skin)

3. Heat loss through conduction involves the transfer of 3. Heat loss through conduction involves the transfer of heat from one surface to another through _________. heat from one surface to another through _________. (direct contact/indirect contact/clothing (direct contact/indirect contact/clothing fibers)fibers)

4. Through evaporation, perspiration is changed from liquid 4. Through evaporation, perspiration is changed from liquid to ____________ and carries heat away with it. to ____________ and carries heat away with it. (gas/solid/vapor)(gas/solid/vapor)

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25.2 Heat-Related Injuries 25.2 Heat-Related Injuries (Hyperthermia)(Hyperthermia)

Most susceptible areMost susceptible are AthletesAthletes Workers near furnaces or ovensWorkers near furnaces or ovens Those in poor physical conditionThose in poor physical condition AlcoholicsAlcoholics The obeseThe obese The chronically illThe chronically ill Those who have not adjusted to the environmentThose who have not adjusted to the environment Those with heart diseaseThose with heart disease People using certain drugs (such as diuretics)People using certain drugs (such as diuretics) Burn victimsBurn victims The elderlyThe elderly ChildrenChildren

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VocabularyVocabulary

EvaporationEvaporation- The loss of body heat when perspiration is - The loss of body heat when perspiration is changed from liquid to vapor respiration The loss of body heat changed from liquid to vapor respiration The loss of body heat through normal breathingthrough normal breathing

HyperthermiaHyperthermia- Greatly increased body temperature- Greatly increased body temperature HeatstrokeHeatstroke- A life-threatening emergency caused by a - A life-threatening emergency caused by a

disturbance in the body’s temperature regulation mechanism, disturbance in the body’s temperature regulation mechanism, characterized by extreme fever, hot and dry or moist skin, characterized by extreme fever, hot and dry or moist skin, delirium, or comadelirium, or coma

Heat exhaustion Heat exhaustion A heat-related emergency caused by A heat-related emergency caused by excessive loss of water and salt through sweating, excessive loss of water and salt through sweating, characterized by cool, clammy skin and a weak, rapid pulse characterized by cool, clammy skin and a weak, rapid pulse

Heat cramps Heat cramps Muscle spasms caused by a disturbance in the Muscle spasms caused by a disturbance in the electrolyte balance of the muscles; generally seen when the electrolyte balance of the muscles; generally seen when the body loses too much salt and other electrolytes during profuse body loses too much salt and other electrolytes during profuse sweatingsweating

HypothermiaHypothermia- Greatly decreased body temperature- Greatly decreased body temperature

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Signs and Symptoms of Signs and Symptoms of HeatstrokeHeatstroke

Body temperature of 105°F or moreBody temperature of 105°F or more Hot, red skin that is moist or dryHot, red skin that is moist or dry Initially rapid, strong pulseInitially rapid, strong pulse Later rapid, weak pulseLater rapid, weak pulse Initially constricted pupilsInitially constricted pupils Later dilated pupilsLater dilated pupils TremorsTremors Mental confusion or anxietyMental confusion or anxiety Irritability or aggressionIrritability or aggression Initially deep, rapid breathingInitially deep, rapid breathing Later shallow, weak breathingLater shallow, weak breathing HeadacheHeadache Dry mouthDry mouth Shortness of breathShortness of breath Loss of appetiteLoss of appetite Nausea and vomitingNausea and vomiting Dizziness and weaknessDizziness and weakness Seizures or sudden collapseSeizures or sudden collapse

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First Aid CareFirst Aid Care

1. Establish an airway and, when possible, remove the 1. Establish an airway and, when possible, remove the victim from the source of heat.victim from the source of heat.

2. Remove as much of the victim’s clothing as possible, 2. Remove as much of the victim’s clothing as possible, down to his or her underwear; then use a combination of down to his or her underwear; then use a combination of methods to cool the victim until his or her mental status methods to cool the victim until his or her mental status returns to normal.returns to normal.

3. Never give the victim stimulants or hot drinks.3. Never give the victim stimulants or hot drinks.4. As the body cools, seizures or vomiting may occur. 4. As the body cools, seizures or vomiting may occur.

Position the victim to allow for easy drainage.Position the victim to allow for easy drainage.5. Monitor the victim’s temperature while you wait for 5. Monitor the victim’s temperature while you wait for

emergency personnel to arrive. If the temperature starts emergency personnel to arrive. If the temperature starts to climb, start cooling procedures again. (The to climb, start cooling procedures again. (The temperature must drop below 102°F and must stay that temperature must drop below 102°F and must stay that low before the danger has passed.) low before the danger has passed.)

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Heat ExhaustionHeat Exhaustion

1. 1. Move the victim to a cool place, remove as much of Move the victim to a cool place, remove as much of the victim’s clothing as possible, and fan the victim the victim’s clothing as possible, and fan the victim lightly. Make sure the victim does not get chilled or lightly. Make sure the victim does not get chilled or begin to shiver. begin to shiver.

2. 2. Have the victim lie down, raise the feet 8 to 12 inches. Have the victim lie down, raise the feet 8 to 12 inches. 3. 3. If the victim is fully conscious, give him or her cool If the victim is fully conscious, give him or her cool

water or commercial sports drink to drink at the rate of water or commercial sports drink to drink at the rate of half a glass every 10 minutes for 1 hour. half a glass every 10 minutes for 1 hour. Never give Never give the victim salt tablets. the victim salt tablets. If the victim is nauseated or If the victim is nauseated or vomits, stop giving fluids and activate the EMS system vomits, stop giving fluids and activate the EMS system immediately.immediately.

4. 4. If the victim is unconscious, immediately activate EMS, If the victim is unconscious, immediately activate EMS, and manage the airway and ventilation.and manage the airway and ventilation.

5. 5. Take the victim’s temperature every 10 to 15 minutes. Take the victim’s temperature every 10 to 15 minutes. If the temperature is above 101°F or is rising, or if the If the temperature is above 101°F or is rising, or if the victim is unable to drink fluids or vomits after victim is unable to drink fluids or vomits after drinking fluids, or the victim does not improve, drinking fluids, or the victim does not improve, immediately activate the EMS system.immediately activate the EMS system.

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Heat CrampsHeat Cramps

1. If the victim is in a hot environment, remove him or 1. If the victim is in a hot environment, remove him or her from the heat immediately; have the victim rest in her from the heat immediately; have the victim rest in a cool place.a cool place.

2. Administer sips of water or a sports drink at the rate 2. Administer sips of water or a sports drink at the rate of half a glass every 15 minutes. of half a glass every 15 minutes. Do not use salt Do not use salt tablets.tablets.

3. Apply moist towels to the victim’s forehead and over 3. Apply moist towels to the victim’s forehead and over the cramping muscles. To relieve pain, try gently the cramping muscles. To relieve pain, try gently stretching the involved muscle groups. stretching the involved muscle groups.

4. Explain to the victim what happened and why so the 4. Explain to the victim what happened and why so the victim can avoid a recurrence; the victim should avoid victim can avoid a recurrence; the victim should avoid exertion of any kind for at least 12 hours, or heat exertion of any kind for at least 12 hours, or heat cramps will recur. Activate the EMS system if the cramps will recur. Activate the EMS system if the victim has other illnesses or injuries, if other victim has other illnesses or injuries, if other symptoms develop, or if the victim’s condition symptoms develop, or if the victim’s condition worsens or does not respond to care.worsens or does not respond to care.

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PROGRESS CHECKPROGRESS CHECK

1. _______________ is a life-threatening condition; untreated, all victims 1. _______________ is a life-threatening condition; untreated, all victims die. die. (Heatstroke/Heat exhaustion/Heat cramps)(Heatstroke/Heat exhaustion/Heat cramps)

2. The two most reliable and distinct differences between heatstroke and 2. The two most reliable and distinct differences between heatstroke and heat exhaustion are body temperature and ____________. heat exhaustion are body temperature and ____________. (level of (level of consciousness/condition of the skin/pattern of breathing)consciousness/condition of the skin/pattern of breathing)

3. In heatstroke, the skin is hot, red, and __________. 3. In heatstroke, the skin is hot, red, and __________. (wet/dry/either wet (wet/dry/either wet or dry)or dry)

4. The top priority in treatment of heatstroke is ____________. 4. The top priority in treatment of heatstroke is ____________. (monitoring (monitoring pulse/immediate cooling of the body/monitoring body temperature)pulse/immediate cooling of the body/monitoring body temperature)

5. If the victim’s temperature starts rising again after you have started 5. If the victim’s temperature starts rising again after you have started treatment for heatstroke, you should ____________. treatment for heatstroke, you should ____________. (activate the EMS (activate the EMS system immediately/submerge the victim in cool water/begin cooling system immediately/submerge the victim in cool water/begin cooling procedures again)procedures again)

6. Heat exhaustion results from ____________. 6. Heat exhaustion results from ____________. (elevated body (elevated body temperature/loss of fluid and electrolytes/vessel dilation)temperature/loss of fluid and electrolytes/vessel dilation)

7. The most critical problem in heat exhaustion is ____________.7. The most critical problem in heat exhaustion is ____________.(dehydration/overheating/circulatory disturbance)(dehydration/overheating/circulatory disturbance)8. Heat cramps occur because of disruption in the muscle’s balance of 8. Heat cramps occur because of disruption in the muscle’s balance of

calcium, water, and ____________. calcium, water, and ____________. (sodium/potassium/phosphorus)(sodium/potassium/phosphorus)9. To treat heat cramps, give the victim sips of ____________. 9. To treat heat cramps, give the victim sips of ____________.

(hot water/cold water/salt water)(hot water/cold water/salt water)

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25.3 Cold-Related Injuries 25.3 Cold-Related Injuries (Hypothermia)(Hypothermia)

Factors contributing to hypothermia, even in the Factors contributing to hypothermia, even in the absence of cold environment, includeabsence of cold environment, include

Certain drugs (i.e., central nervous system Certain drugs (i.e., central nervous system depressants)depressants)

SurgerySurgery Water activitiesWater activities Existing diseaseExisting disease TraumaTrauma Massive blood lossMassive blood loss Extremes of age (very young or very old)Extremes of age (very young or very old) ImmobilityImmobility

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Signs and SymptomsSigns and Symptoms

Skin that is cold to the touch (To test, place the back of your hand Skin that is cold to the touch (To test, place the back of your hand against the skin of the victim’s abdomen.)against the skin of the victim’s abdomen.)

Uncontrollable shiveringUncontrollable shivering Vague, slurred, thick speechVague, slurred, thick speech Amnesia and incoherenceAmnesia and incoherence Disorientation, confusionDisorientation, confusion Poor judgmentPoor judgment Staggering gaitStaggering gait DizzinessDizziness Pale, cold, waxen skinPale, cold, waxen skin Stiff and hard musclesStiff and hard muscles Sluggish pupilsSluggish pupils Increased heart and respiratory rates (early)Increased heart and respiratory rates (early) Decreased heart and respiratory rates (late)Decreased heart and respiratory rates (late) DehydrationDehydration Drowsiness and/or stuporDrowsiness and/or stupor Apparent exhaustionApparent exhaustion UnconsciousnessUnconsciousness

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First Aid CareFirst Aid Care

1. Check the victim’s vital signs. Measure for 1 full minute, 1. Check the victim’s vital signs. Measure for 1 full minute, because vital signs are slowed and weak in hypothermia. If because vital signs are slowed and weak in hypothermia. If there is no pulse, open the airway and begin CPR. If an AED is 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 available, deliver only one shock. If that does not correct the rhythm, continue CPR and do not deliver any additional shocks.rhythm, continue CPR and do not deliver any additional shocks.

2. Handle the victim 2. Handle the victim very very gently. Don’t let the victim walk around gently. Don’t let the victim walk around or move much on his or her own. or move much on his or her own.

3. Keep the victim in a supine position to prevent shock and 3. Keep the victim in a supine position to prevent shock and increase blood flow to the brain. increase blood flow to the brain. Do not elevate the legs; Do not elevate the legs; doing doing so causes cold blood to flow to the heart. so causes cold blood to flow to the heart.

4. Prevent further heat loss4. Prevent further heat loss5. Never rub or manipulate the arms or legs; you could force cold 5. Never rub or manipulate the arms or legs; you could force cold

blood from the veins into the core circulation and heart, blood from the veins into the core circulation and heart, causing abnormal heart rhythm or cardiac arrest.causing abnormal heart rhythm or cardiac arrest.

6. Never give the victim tobacco, coffee, or alcohol. Give warm 6. Never give the victim tobacco, coffee, or alcohol. Give warm fluids only after uncontrollable shivering stops and the fluids only after uncontrollable shivering stops and the victim is completely conscious. victim is completely conscious.

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First Aid Care for Severe First Aid Care for Severe HypothermiaHypothermia

1. 1. Never Never try to rewarm a severely hypothermic victim. try to rewarm a severely hypothermic victim. Insulate the victim against further heat loss, but do Insulate the victim against further heat loss, but do not apply any source of heat. Handle the victim not apply any source of heat. Handle the victim extremely extremely gently.gently.

2. Assess vital signs over a 1-minute period; if there is 2. Assess vital signs over a 1-minute period; if there is no heartbeat during the 1 minute, start CPR.no heartbeat during the 1 minute, start CPR.

3. If the victim is not breathing, administer gentle 3. If the victim is not breathing, administer gentle mouth-to-mouth or mouth-to-mask/barrier device at mouth-to-mouth or mouth-to-mask/barrier device at a rate of 10 to 12 breaths per minute in an adult or a rate of 10 to 12 breaths per minute in an adult or 12 to 20 breaths per minute in an infant or child. 12 to 20 breaths per minute in an infant or child.

4. Maintain airway, breathing, and circulation until 4. Maintain airway, breathing, and circulation until EMTs arrive.EMTs arrive.

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Immersion HypothermiaImmersion Hypothermia

1. Activate the EMS system immediately.1. Activate the EMS system immediately.

2. Maintain the victim’s airway, breathing, and 2. Maintain the victim’s airway, breathing, and circulation.circulation.

3. Keep the victim still and quiet; the coldest blood is 3. Keep the victim still and quiet; the coldest blood is in the extremities, and it will circulate rapidly to the in the extremities, and it will circulate rapidly to the heart with movement.heart with movement.

4. Follow insulating and rewarming guidelines as for 4. Follow insulating and rewarming guidelines as for general hypothermia, remembering to handle the general hypothermia, remembering to handle the victim victim very very gently.gently.

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FrostbiteFrostbite

1. Immediately remove the victim from the cold 1. Immediately remove the victim from the cold environment.environment.

2. Keep the tissue frozen until you can initiate care; 2. Keep the tissue frozen until you can initiate care; never never thaw tissue if there is any chance of its refreezing thaw tissue if there is any chance of its refreezing

3. Protect the injured tissue from friction or pressure; never 3. Protect the injured tissue from friction or pressure; never poke or squeeze the tissue. Remove constricting clothing poke or squeeze the tissue. Remove constricting clothing or jewelry that is not sticking to the skin.or jewelry that is not sticking to the skin.

4. Thaw frostbitten tissue4. Thaw frostbitten tissue in a water bath. in a water bath. 5. Keep rewarming until the skin color no longer improves 5. Keep rewarming until the skin color no longer improves

(rewarming to this point may take as long as 40 minutes).(rewarming to this point may take as long as 40 minutes).6. Cover the thawed parts with loose, dry, sterile dressings 6. Cover the thawed parts with loose, dry, sterile dressings

and elevate the extremities. Place sterile gauze between and elevate the extremities. Place sterile gauze between the fingers and toes to reduce the risk of increased injury.the fingers and toes to reduce the risk of increased injury.

7. While waiting for emergency personnel to arrive, monitor 7. While waiting for emergency personnel to arrive, monitor vital signs and keep the victim warm. Do not let vital signs and keep the victim warm. Do not let the victim walk if the feet are involved, and do not the victim walk if the feet are involved, and do not let the victim smoke. Do not re-expose the thawed let the victim smoke. Do not re-expose the thawed part to the cold. part to the cold.

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PROGRESS CHECKPROGRESS CHECK

1. Because taking core temperature is difficult in the field, you 1. Because taking core temperature is difficult in the field, you should rely on ____________ to identify hypothermia. should rely on ____________ to identify hypothermia. (skin (skin temperature/signs and symptoms/what the victim tells you)temperature/signs and symptoms/what the victim tells you)

2. The priority in treating hypothermia is to ____________.2. The priority in treating hypothermia is to ____________.(start rewarming right away/remove the victim from the cold (start rewarming right away/remove the victim from the cold

environment/rewarm rapidly)environment/rewarm rapidly)3. Rewarm a hypothermia victim only if the victim ____________.3. Rewarm a hypothermia victim only if the victim ____________.(does not respond to other treatment/has a further temperature (does not respond to other treatment/has a further temperature

drop/cannot be transported immediately)drop/cannot be transported immediately)4. The priority in treating immersion hypothermia is _________.4. The priority in treating immersion hypothermia is _________.(getting the victim out of the water/preventing drowning/drying (getting the victim out of the water/preventing drowning/drying

the victim)the victim)5. You should never thaw frostbitten tissue if there is any danger 5. You should never thaw frostbitten tissue if there is any danger

of ____________. of ____________. (refreezing/delayed transport/increased injury)(refreezing/delayed transport/increased injury)6. Frostbitten tissue should be thawed using __________.6. Frostbitten tissue should be thawed using __________.(steam/dry heat/warm water)(steam/dry heat/warm water)