Exposure to heat and cold

By Rebecca Mills

The nature of the conditionHyperthermia & Hypothermia

Exposure to heat or cold in excessive amounts can have severe effects on the human body. The two extreme temperatures of heat and cold are known as Hyperthermia, meaning hot or high body temperature, and Hypothermia, meaning cold or low body temperature.

Hyperthermia

Hyperthermia is extreme body heat which is often associated with a high body temperature; one that dangerously exceeds the normal temperature of 37 C. Two forms of hyperthermia are heat stroke, and heat exhaustion.

Hypothermia

Hypothermia is extremely cold body temperature and is often caused by exposure to cold, wind, rain or submersion in water. Young children and older adults are more susceptible to hypothermia. One of the most common related illness to extremely cold temperature is frostbite.

The nature of the conditionThe main forms of Hyperthermia

Heat exhaustionHeat exhaustion is typically brought on by an exposure to excessive heat for a long period of time. It is actually a form of shock, although only mild, and is caused by a loss of fluid and salt. It causes blood to merge in the skin in an attempt to rid itself of excess heat, which is why those suffering from heat exhaustion appear flushed. Heat exhaustion is most commonly suffered by those who have been exercising, or working in excessive heat. Other risk factors include young and elderly people, hot and humid climates and unsuitable clothing.

Heat strokeHeat stroke is a serious hyperthermia related illness. If left untreated, it can cause brain damage, coma and ultimately death. It is a condition which sees the body’s temperature continually rising, and the inability to rid itself of excess heat. It is worsened when the sufferer fails to sweat in response to the loss of fluid and salt.Risk factors for heat stroke include athletes, infants and children in closed cars, the elderly, ill people and unfit and overweight people.

A person suffering from heat stroke

Nature of the conditionHyperthermia – other forms

Other forms of Hyperthermia include:

Heat cramps Painful muscle cramps due to long exposure to heat usually in the abdomen, arms or legs. Symptoms: exhaustion, dizziness, severe muscle cramps.

Heat fatigue Feeling of weakness caused by high outdoor temperatures. Symptoms: faintness, cool and moist skin, weakened pulse.

Heat stress A strain on the body caused by hot weather.

Heat syncope Sudden dizziness from exercise or activity in the heat. Symptoms: pale and sweaty skin that is generally moist and cool, weakened pulse and rapid heart rate, normal body temperature.

Signs and SymptomsForms of Hyperthermia (heat stroke and exhaustion)

Some common signs and symptoms of heat exhaustion include:

Sign SymptomVomiting Exhaustion

Sweating Headache

Lack of coordination Nausea

Rapid and shallow breath

Thirst

Stomach cramps

Loss of appetite

Dizziness

Temperature > 37 C

Some common signs and symptoms of heat stroke include:

Sign SymptomIrrational behaviour Confusion

Dry, hot skin Visual disturbances

Seizures Rapid, pounding pulse

Deep breaths, followed by shallow breathing

Dilated pupils

Unconsciousness

Management techniquesCurrent primary management techniques for: heat exhaustion1. DRABCD.2. Move the casualty to a nearby cool place.3. Lay casualty down and keep them at rest.4. Loosen tight clothing – allow enough to cool them without chilling them.5. Sponge with cool water or apply cool, wet towels around the neck and underarms.6. If possible, fan the casualty's skin7. Give cool fluids to sip, preferably water. NEVER give fluids to an unconscious person.8. Monitor closely.8. Seek medical advice.

Current primary management techniques for: heat stroke1. DRABCD and call 000 for an Ambulance.2. Give Basic Life Support as required.3. Move the casualty to a nearby cool place.4. Lay the casualty down. If unconscious, place the casualty in the recovery position.5. Remove unnecessary excess clothing.6. Apply cold packs to groin, neck and armpits.7. Give cool fluids only if fully conscious.8. Monitor breathing.

Applying cool packs to casualty

Lay casualty down and keep at rest

Management techniques

The nature of the conditionHypothermia - Frostbite

FrostbiteFrostbite is the result of excessive cooling to a body part/s, and occurs when the tissues of the body freeze. It most commonly affects the body’s extremities; the fingers, toes, cheeks, nose and ears. Frostbite results from an exposure to very low temperatures, ones that are below the freezing point of skin.

A severe case of frostbite to the toesChildren are at a greater risk to frostbite than adults. This is because they lose heat from their bodies more quickly than adults do.

Signs and SymptomsHypothermia and Frostbite

Sign SymptomPale Confusion

Shivering (may stop as condition worsens)

Drowsiness

Lack of coordination

Eventual unconsciousness

Hypothermia

Frostbite

Sign SymptomHard, stiff skin Prickling pain in

affected area/s

White, waxy skin

Numbness

Impaired movement

Frostbite on the fingers

Management techniquesCurrent primary management techniques for: hypothermia1. DRABCD and call for medical assistance as soon as possible.2. If possible, move casualty to a warm, dry place.3. Prevent further body cooling. Replace wet clothing with dry items, or wrap in dry blankets.4. Handle gently and keep the body horizontal.Keep the casualty at rest and do not allow them to walk.5. Gently and gradually re-warm using heat packs, hot water bottles, or hot air. If they are unavailable, use body heat. 6. If conscious, slowly give casualty warm sweet drinks.

Do not rub or massage affected parts. Do not apply direct heat or give alcohol.

Current primary management techniques for: frostbite1. DRABCD2. Remove to a warm or sheltered place, if possible, to prevent further heat loss.3. Keep affected body part elevated to reduce swelling.4. Remove all constrictive clothing or jewellery.5. Cover any blisters with dry, sterile dressings.6. Get medical help – call 000.

Management techniques

Slowly give casualty warm, sweet drinks if conscious

Bibliography

WWW Resources: The Excite Network. (no date). Hyperthermia. (online)

http://www.healthscout.com/ency/407/271/main.html Retrieved: 23.08.08 E Medicine Health. (2008). Frostbite Causes. (online)

http://www.emedicinehealth.com/frostbite/page2_em.htm Retrieved: 24.08.08 Nemours Foundation. (July 2008). Frostbite. (online).

http://kidshealth.org/parent/firstaid_safe/emergencies/frostbite.html Retrieved: 24.08.08

Old Tappan. (no date). First Aid Tips – Heat and Cold. (online). http://oldtappan.net/first_aid_heatcold.cfm Retrieved: 23.08.08

New South Wales Government, Ambulance Service of NSW. (2007). First Aid. (online). http://www.asnsw.health.nsw.gov.au/community_info/first_aid.html Retrieved: 23.08.08

Books: The State of New South Wales, Department of Education and Training, TAFE NSW,

Community Services, Health, Tourism and Recreation Curriculum Centre (2006). Senior First Aid Textbook. Meadowbank: Queensland.