First AidFirst AidLecture 4Lecture 4

. . EFFECTS EFFECTS

OFOF

TEMPERATURETEMPERATURE

• In health, the core body temperature is maintained by the thermoregulatory centre in the hypothalamus at a constant 37oC.

•Heat is produced by cellular metabolism & is lost through the skin by vasodilatation, sweating & in air expired from the lungs.

•The evaporation of sweat is the vital mechanism keeping the skin cool & the body temperature down.

Hypothalamus maintains normal temp through:– Heating mechanisms: Heating mechanisms:

•ShiveringShivering•Cessation of sweatingCessation of sweating•Secretion of NE, E, and thyroxine to heat Secretion of NE, E, and thyroxine to heat

productionproduction•vasoconstriction vasoconstriction

– Cooling mechanisms: Cooling mechanisms: •Sweating & dilating cutaneous blood vessels.Sweating & dilating cutaneous blood vessels.

Exposure to extremes of temperature is harmful for body functions and may be damaging to body tissues.

The harmful effects of extreme heat or The harmful effects of extreme heat or cold can be cold can be localizedlocalized as in the case of as in the case of frostbite & sunburn frostbite & sunburn or or generalizedgeneralized as as with with hypothermia, heat exhaustion & hypothermia, heat exhaustion & heatstrokeheatstroke..The generalized effects of extremes of The generalized effects of extremes of temperature occur more often temperature occur more often in the in the very very youngyoung & & very oldvery old, whose , whose temperature-regulation systems may temperature-regulation systems may respectively be respectively be underdevelopedunderdeveloped or or impairedimpaired..

THE FIRST AIDER THE FIRST AIDER SHOULD:SHOULD:

Remove or protect the casualty from excessively hot or cold surroundings.Restore normal body temperature; if the condition has been rapid in onset (e.g. heat stroke), reverse it rapidly. If has developed slowly (hypothermia of slow onset affecting an elderly person), the casualty’s body temperature must be gradually restored to normal.Obtain appropriate medical attention.

EFFECTS OF EXTREME EFFECTS OF EXTREME COLDCOLD

The body reacts to cold by The body reacts to cold by shutting down shutting down blood vessels in the skin to stop core heat blood vessels in the skin to stop core heat escapingescaping. When deprived of warm blood, . When deprived of warm blood, extremities such as fingers or toes may freeze extremities such as fingers or toes may freeze in severe conditions, causing frostbite.in severe conditions, causing frostbite.If the body’s core temperature becomes If the body’s core temperature becomes dangerously low (dangerously low (hypothermiahypothermia), ), bodily bodily functions slow downfunctions slow down & may cease all together. & may cease all together.

FROSTBITEFROSTBITE

This condition occurs in freezing & often dry & windy conditions.This condition occurs in freezing & often dry & windy conditions.Those who cannot move are particularly vulnerable.Those who cannot move are particularly vulnerable.The tissues of the extremities The tissues of the extremities freezefreeze, in severe cases this can lead , in severe cases this can lead to to permanent loss of sensation permanent loss of sensation & eventually & eventually gangrenegangrene..

symptoms:symptoms:•At first pins & needles.At first pins & needles.

•Paleness & numbness.Paleness & numbness.

•A hardening & stiffening of the skin .A hardening & stiffening of the skin .

•A color change to the skin of the affected area; first white, then A color change to the skin of the affected area; first white, then blue & eventually black. On recovery; red, hot, painful & blistered.blue & eventually black. On recovery; red, hot, painful & blistered.

MANAGEMENT:MANAGEMENT:

1.1. Warm the affected area slowly to prevent further tissue Warm the affected area slowly to prevent further tissue damage.damage.

• Very gently remove gloves, rings & any constrictions as boots.Very gently remove gloves, rings & any constrictions as boots.

• Warm the affected part with your hands (avoid rubbing Warm the affected part with your hands (avoid rubbing because it can damage skin & tissues).because it can damage skin & tissues).

2.2. Move the casualty into warmth before you thaw the affected Move the casualty into warmth before you thaw the affected part.part.

3.3. Place the affected part in warm water. Dry carefully & apply a Place the affected part in warm water. Dry carefully & apply a light dressing of dry gauze bandage.light dressing of dry gauze bandage.

4.4. Raise & support the limb to reduce swelling.Raise & support the limb to reduce swelling.

5.5. An adult casualty may take 2 paracetamol tablets for intense An adult casualty may take 2 paracetamol tablets for intense painpain

Hypothermia: Hypothermia:

• DefinitionDefinition: Body Temp < 35 ºC. : Body Temp < 35 ºC.

Lethal if < 32Lethal if < 32ooCC

• ↑↑ Risk of cardiac arrest Risk of cardiac arrest (death from ventricular (death from ventricular fibrillation)fibrillation)..

Elderly (decrease in feel of cold & insulating fat layer) and young children (large surface area & lack of subcutaneous fat ) are more liable to hypothermia.

Causes:Causes:

•Poor heating (prolonged exposure Poor heating (prolonged exposure to cold especially in wet & windy to cold especially in wet & windy conditions).conditions).•Wet or inadequate clothing.Wet or inadequate clothing.•Uncovered head during cold Uncovered head during cold weather.weather.(exposure to extremes of temp (exposure to extremes of temp outside outside (climbers, arctic travellers, (climbers, arctic travellers, wet cold conditions & inadequate wet cold conditions & inadequate clothing)clothing)

Immersion in Immersion in cold water cold water (at temp 15-20 (at temp 15-20 ooC). C). If <12 If <12 ooCC patients’ limbs become anesthetized & paralysed.patients’ limbs become anesthetized & paralysed.

Death from immersion in cold water may be caused by Death from immersion in cold water may be caused by hypothermia not drowning. When surrounded by cold hypothermia not drowning. When surrounded by cold water, the body cools 30 times faster than in dry air, water, the body cools 30 times faster than in dry air, leading to a dangerously lowering of body temperature.leading to a dangerously lowering of body temperature.

•Cardiovascular diseases.Cardiovascular diseases.

•Malnutrition.Malnutrition.

•Hypothyroidism (cold-Hypothyroidism (cold-intolerance). intolerance).

•Certain medications Certain medications (barbiturates, tricyclic (barbiturates, tricyclic antidepressants, etc.) & alcohol.antidepressants, etc.) & alcohol.

Symptoms:Symptoms:

• ShiveringShivering. . • Abnormally Abnormally slow breathingslow breathing. . • Cold, Cold, pale & dry skinpale & dry skin. . • Fatigue, lethargyFatigue, lethargy..• Muscle stiffnessMuscle stiffness develops & tendon develops & tendon

reflexes are depressed.reflexes are depressed.• In severe hypothermia In severe hypothermia (<32(<32ooC)C), ,

impairment of judgement, impairment of judgement, altered altered consciousnessconsciousness & & comacoma..

• ConfusionConfusion..

• Slow & weakening pulse & volumeSlow & weakening pulse & volume fallfall & & so so decrease in blood pressuredecrease in blood pressure, respiration , respiration becomes shallow & slow.becomes shallow & slow.

• Death from cardiac arrest Death from cardiac arrest ..

First Aid Management:First Aid Management:

• Call EMS, monitor ABCs. Call EMS, monitor ABCs.

• Rewarm the patient Rewarm the patient (place in warm (place in warm room, cover with blanket & give room, cover with blanket & give warm fluids orally).warm fluids orally).

• MoveMove the person the person out of the coldout of the cold. . CoverCover his his head & body.head & body.

• RemoveRemove wet clothing. wet clothing.

• Apply Apply warm compresseswarm compresses to the neck, chest to the neck, chest wall, groin & axilla. wall, groin & axilla.

• Give the person Give the person warm warm non-alcoholic non-alcoholic decaffeinated decaffeinated drinksdrinks. .

““Handle gently because of risk of cardiac Handle gently because of risk of cardiac arrest”arrest”

EFFECTS OF EXTREME EFFECTS OF EXTREME HEATHEAT

When the atmospheric temperature is the same as your body When the atmospheric temperature is the same as your body temperature, the body cannot lose heat by radiation or by evaporation. temperature, the body cannot lose heat by radiation or by evaporation. If there is also a humid atmosphere, sweat will not evaporate from the If there is also a humid atmosphere, sweat will not evaporate from the body. In these circumstances (during strenuous exercise) when the body. In these circumstances (during strenuous exercise) when the body generates more heat, heat exhaustion or heatstroke can occur.body generates more heat, heat exhaustion or heatstroke can occur.

HEAT EXHAUSTION:HEAT EXHAUSTION:

This condition usually develops gradually & is caused by loss of salt & This condition usually develops gradually & is caused by loss of salt & water from the body through excessive sweating (working or exercise in water from the body through excessive sweating (working or exercise in hot environment).hot environment).The symptoms may range from minor complaints to more pronounced The symptoms may range from minor complaints to more pronounced symptoms (no nervous system manifestations noted with heat stroke).symptoms (no nervous system manifestations noted with heat stroke).

.. Symptoms: Symptoms:

•A normal or mildly elevated body temperature,A normal or mildly elevated body temperature,

•Heavy sweating with pale & clammy skinHeavy sweating with pale & clammy skin

•Muscle cramps in arms, legs or the abdominal wallMuscle cramps in arms, legs or the abdominal wall

•Fatigue & weaknessFatigue & weakness

•Dizziness, Headache, and confusion Dizziness, Headache, and confusion

•Loss of appetite & nausea. Loss of appetite & nausea.

•Rapid, weakening pulse & breathingRapid, weakening pulse & breathing

If heat exhaustion is untreated and heat exposure continues, it may sometimes progress to heat stroke. If heat exhaustion is untreated and heat exposure continues, it may sometimes progress to heat stroke.

Your aims are:Your aims are:

To replace lost fluids & saltTo replace lost fluids & salt

To cool down the casualtyTo cool down the casualty

Management:Management:Help the casualty to a cool place. Lay him down & raise his legs.Help the casualty to a cool place. Lay him down & raise his legs.Give him plenty of water, with weak salt solutionGive him plenty of water, with weak salt solutionTake a cool shower or bath, andTake a cool shower or bath, andLoosen or remove clothing.Loosen or remove clothing.

Seek medical attention immediately if: Seek medical attention immediately if:

The symptoms are severe, or The symptoms are severe, or

serious underlying health problems (heart disease or serious underlying health problems (heart disease or diabetes). ).

Otherwise, help the person cool off, and seek medical attention if symptoms worsen or last longer than one hourOtherwise, help the person cool off, and seek medical attention if symptoms worsen or last longer than one hour

Heat Stroke•Anyone in a high environmental

temp, particularly in case of high humidity, who exercises vigorously & wears clothing which inhibit heat loss, is at risk of elevation in temp.

•Heat stroke results from exercises or heavy work in hot environment combined with inadequate fluid intake.

Heatstroke is life-threatening: as the body loses its normal

mechanisms for dealing with heat stress, such as sweating and temperature control.

High risk: Young children, elderly, obese people and people with impaired ability to sweat.

•Dehydration, alcohol use, cardiovascular disease & medications are risk factors.

Causes:Causes:• Exercise or heavy work in hot Exercise or heavy work in hot

environments & inadequate fluid environments & inadequate fluid intake. intake.

• Dehydration.Dehydration.

• Alcohol use.Alcohol use.

• Cardiovascular disease.Cardiovascular disease.

• Certain medications Certain medications (anticholinergics, phenothiazines, (anticholinergics, phenothiazines, diuretics, etc.). diuretics, etc.).

Symptoms:Symptoms:• high body temperature (above 40 C), high body temperature (above 40 C),

• skin that is red, hot, and either moist or skin that is red, hot, and either moist or dry (sweating may have stopped), dry (sweating may have stopped),

• rapid heart rate,rapid heart rate,

• difficulty breathing, difficulty breathing,

• headache, dizziness,headache, dizziness,

• loss of coordination,loss of coordination,

• nausea and vomiting,nausea and vomiting,

• confusion and restlessness,confusion and restlessness,

• seizures, and unconsciousness/coma. seizures, and unconsciousness/coma.

First Aid Management:First Aid Management:• MoveMove the person the person out of the sunout of the sun into a into a

shady or air-conditioned space. shady or air-conditioned space. • Lay the person down & Lay the person down & elevate the legselevate the legs

slightly. slightly. • Call Call EMSEMS. . • Cool the personCool the person (covering him with (covering him with

damp sheets, spraying or sponging him damp sheets, spraying or sponging him with cool water, use a fan or with cool water, use a fan or newspaper). newspaper).

• Have the person Have the person drink cool water drink cool water (oral (oral rehydration with water & salts)rehydration with water & salts)..

• LoosenLoosen or remove the person's or remove the person's clothingclothing. .

Monitor body temperature, and continue cooling efforts until the body temperature drops to about Monitor body temperature, and continue cooling efforts until the body temperature drops to about 38.8 C or lower, in order to prevent overcooling the affected individual. 38.8 C or lower, in order to prevent overcooling the affected individual. Sometimes the affected individual's muscles will begin to twitch uncontrollably (seizure) as a result of Sometimes the affected individual's muscles will begin to twitch uncontrollably (seizure) as a result of heat stroke. If this happens, keep the person from injuring him or herself, but do not place any object heat stroke. If this happens, keep the person from injuring him or herself, but do not place any object in the mouth and do not give fluids. in the mouth and do not give fluids. If there is vomiting, make sure the airway remains open by turning the person on his or her side to If there is vomiting, make sure the airway remains open by turning the person on his or her side to prevent choking.prevent choking.

Hyperthermia (fever)

Fever is the elevation of body temperature

( > 37°C).

Fever is one of the body's reactions to infection.

Generally treatment of fever depends on its cause.

Causes:Infections (bacterial, fungal, viral,

etc.). Poisons.Heat exposure. Some medications (thyroxine,

amphetamines, antihistaminics, sedatives, some antidepressants, anticonvulsants, etc.).

Some diseases (cancer, inflammation, endocrine disorders, HIV, autoimmune diseases, etc.).

When to Seek Medical Help?In babies with rectal

temperature>38.0 °C. In children and adults with fever

persists for three days.If you suspect dehydration

especially in children (sunken eyes, dry diapers).

If febrile seizures develop in children.

If any of these signs or symptoms accompanies fever:

Unusual skin rashMental confusion. Persistent vomiting. Difficulty in breathing or chest

pain. Abdominal pain.Pain when urinating or blood in

stool.

Severe headache.Severe swelling of the throat.Unusual eye sensitivity to light.Stiff neck & pain when the head

bent forward.Leg swelling. Lack of appetite and difficulty in

sleeping in children

First Aid Measures:A- In Adults:Fever can be reduced with ibuprofen or

acetaminophen. People with stomach ulcers or kidney

disease, pregnant women and those with aspirin allergy should avoid ibuprofen.

Extremely large doses of acetaminophen may cause liver failure and it should not be given to people with liver disease.

Fever can result in dehydration; hence patient should drink lots of fluids.

If the fever is caused by exposure to hot weather or overexertion or if the patient was confused or unconscious, neither acetaminophen nor ibuprofen will be effective.

The person needs to be cooled immediately (remove patient from the hot environment; remove his or her clothes and cool the body with a wet sponge with a fan directed over the person).

B- In Children:Use acetaminophen or ibuprofen to

reduce temperature for at least 24 hours (if conscious).

Dress the child in light cotton clothes and avoid overdressing.

You can give him a warm bath but do not use alcohol in a bath or rub it on the skin.

Try to give the child fluids to help in reducing the temperature as clear fluids such as non-carbonated decaffeinated drinks or juice (not water as it does not contain the necessary electrolytes and glucose).

Do not give tea or any caffeine-containing product as it promotes water loss through urination.

If the child is vomiting, an anti-emetic drug may be given by injection or by rectal suppository. After a period of time, oral fluids will be attempted.

Aspirin is contraindicated (Reye syndrome, sudden loss of consciousness following a prodromal infection, resulting in death with cerebral edema, marked fatty changes in liver & renal tubules).

Febrile convulsions (in children):

If a child suffers from fever (Temp = 39-40C) due to any cause convulsions may occur.

The child seems flushed, sweating, his eyes may roll up and his face may show bluish discoloration.

Convulsions appear as stiffness in the neck with arched body.

•Type:Type: generalized.generalized.

•Duration:Duration: few min/self-limiting.few min/self-limiting.

• Incidence:Incidence: children (6 months - 6 children (6 months - 6 years). years). (because developing brain is (because developing brain is sensitive to effects of fever)sensitive to effects of fever)

Causes:Causes:

•Viral & bacterial infections. Viral & bacterial infections.

•Serious CNS infection e.g. meningitis.Serious CNS infection e.g. meningitis.

Febrile seizures represent the meeting point between a Febrile seizures represent the meeting point between a low seizure threshold low seizure threshold (genetically and age-(genetically and age-determined; some children have a greater tendency to have seizures under certain circumstances) determined; some children have a greater tendency to have seizures under certain circumstances) and and a triggera trigger, which is , which is feverfever. . A febrile seizure is the effect of a A febrile seizure is the effect of a sudden rise in temperature (>39°C) sudden rise in temperature (>39°C) rather than a fever that has rather than a fever that has been present for a prolonged length of time. been present for a prolonged length of time.

Parents caring for children that may be febrile who wrap them up in warm blankets in an attempt to Parents caring for children that may be febrile who wrap them up in warm blankets in an attempt to give comfort unknowingly increase their fever and therefore the riskgive comfort unknowingly increase their fever and therefore the risk. .

Symptoms:Symptoms:

•StiffeningStiffening of entire body. of entire body.

• JerkingJerking of arms & legs. of arms & legs.

•Complete Complete lack of responselack of response to any to any stimuli. stimuli.

•Urinary incontinence.Urinary incontinence.

•TightnessTightness of the jaws and mouth. of the jaws and mouth.

•Slow breathSlow breath..

When to Seek Medical Care?When to Seek Medical Care?

• Seizure lasts Seizure lasts > 5 min> 5 min. .

• Difficult or Difficult or stopped breathingstopped breathing. .

• CyanosisCyanosis develops. develops.

Figure 10

Management:

Protect child’s airway.

Control the fever: remove clothing, apply cool washcloths to the face and neck.

Sponge the rest of the body with cool water (do not immerse a seizing child in the bathtub).

“Give acetaminophen suppositories”

Never give him anything by mouth

At the end of the fit put him in the recovery position.

Give benzodiazepines to stop seizures.

Do not try to restrain child or force anything into the child's mouth.