Effects of heat and cold

The human body normally regulates its own temperature very well, but can be affected in a number of ways when it suffers the effect of extreme temperature, in particular the very young or elderly are the most susceptible to the effects of heat and cold.

Contact to hot materials/surfaces can cause burns or scalds, the longer the contact the more severe the injury will be. Corrosive chemicals can also cause burns. Exposure to extreme heat can cause conditions such sunburn, prickly heat and possibly heatstroke. Extreme cold can also lead to hypothermia and frost bite.

First aiders should always remember ensure that any danger to you is removed before attempting to commence treatment.

1. Burns and scalds

Severe burns

Treatment

• Start cooling the burn immediately under running water for at least 10 minutes
• Dial 999 for an ambulance.
• Make the casualty as comfortable as possible, lie them down.
• Continue to pour copious amounts of cold water over the burn for at least ten minutes or until the pain is relieved.
• Whilst wearing disposable gloves, remove jewellery, watch or clothing from the affected area - unless it is sticking to the skin.
• Cover the burn with clean, non-fluffy material to protect from infection. Cloth, a clean plastic bag or kitchen film all make good dressings.
• Treat for shock.

Minor burns

Treatment

For minor burns, hold the affected area under cold water for at least 10 minutes or until the pain subsides. Remove jewellery etc. and cover the burn as detailed above.

If a minor burn is larger than a postage stamp it requires medical attention. All deep burns of any size require urgent hospital treatment.

Clothing on fire

Treatment

• Stop the casualty panicking or running – any movement or breeze will fan the flames.
• Drop the casualty to the ground.
• If possible, wrap the casualty tightly in a coat, curtain or blanket (not the nylon or cellular type), rug or other heavy-duty fabric. The best fabric is wool.
• Roll the casualty along the ground until the flames have been smothered.

On all burns:

• Do not use lotions, ointments and creams.
• Do not use adhesive dressings.
• Do not break blisters.

2. Prickly heat

Prickly heat is a highly irritating prickly red rash, hence the name, and it most commonly occurs in hot weather.

It is caused by bacteria or dead skin cells blocking sweat glands. The rash particularly affects areas where sweat is trapped and cannot evaporate, such as the feet for instance. People who often have prickly heat also tend to be susceptible to heat stroke.

Recognition features

You can recognise prickly heat by a prickling or burning sensation over the effected area, there will also be a rash of tiny red spots or blisters.

Treatment

Your main aim is to relieve any discomfort and pain so you should encourage the person to stay in cool conditions as much as possible, and cool the skin by gently sponging with cold water.

3. Sunburn

Introduction

Sunburn can be caused by overexposure to the sun or even a sun lamp. At high altitudes sunburn can occur even on an overcast summer day. Some medicines can trigger severe sensitivity to sunlight and rarely it can be caused by exposure to radioactivity.

Most sunburn is superficial. In severe cases, the skin is a lobster red in colour and blistered - the casualty may also be suffering from heatstroke.

Recognition

Sunburn is often recognised by:

• Reddened skin.
• Pain in the area of the burn.
• Later there may be blistering to the affected skin.

Treatment

Your aims when dealing somebody with sunburn is to move the casualty out of the sun or away from the source of the sunburn and to relieve any discomfort and pain.

Caution though, if there is extensive blistering or any other skin damage you need to seek medical advice.

• With minor sunburn cover the casualty’s skin with light clothing or a towel.
• Move them into the shade or preferably indoors.
• Cool the skin by sponging it with cool water or by soaking the affected area in a cold bath or a cool shower for ten minutes.
• Encourage the casualty to have frequent sips of cold water.
• If the burns are mild calomine lotion or an aftersun preparation may soothe them.
• For severe sunburn obtain medical aid.

4. Heatstroke

Introduction

This condition is caused by a failure in the thermostat in the brain. This regulates the body temperature. The body then becomes dangerously overheated usually due to a high fever or prolonged exposure to heat.

Heatstroke can also result form the use of drugs such as ecstasy.

In some cases heatstroke follows heat exhaustion when sweating ceases and the body then cannot be cooled by the evaporation of sweat. Heatstroke can develop with very little warning, causing unconsciousness within minutes of the casualty feeling unwell.

Recognition

Recognition features may include:

• Headache.
• Dizziness and discomfort.
• Restlessness and confusion.
• Hot flushed and dry skin.
• A rapid deterioration in the level of response.
• A full bounding pulse.
• A body temperature above 40 degrees celsius or 104 degrees fahrenheit.

Treatment

Your aims are to lower casualty’s body temperature as quickly as possible and arrange urgent removal to hospital.

• You need to quickly move the casualty to a cool place and remove as much of the outer clothing as possible.
• Dial 999 or 112 for an ambulance.
• Wrap the casualty in a cold wet sheet and keep the sheet wet until the temperature falls to 38 degrees celsius, or 100.4 degrees fahrenheit, under the tongue or under the armpit.
• If no sheet is available, fan the casualty or sponge them down with cold water. Once the casualty’s temperature appears to have returned to normal replace the wet sheet with a dry one.
• Always monitor and record the vital signs, the level of response, pulse and breathing rate until help arrives.
• If the temperature starts to rise again repeat the cooling process.
• Caution though, if the casualty becomes unconscious open the airway and check breathing and be prepared to give rescue breaths and chest compressions if necessary, or if the casualty is unconscious but breathing normally place them into the recovery position, please refer to the relevant tips.

5. Heat exhaustion

Introduction

Heat exhaustion is caused by a loss of salt and water from the body, usually through excessive sweating.

It develops gradually and it usually happens to people who are not acclimatised to hot humid conditions or people that are unwell, especially those with illnesses that cause vomiting and diarrhoea. They are more susceptible than others to developing heat exhaustion.

A dangerous and common cause of heat exhaustion is the excessively high body temperature and other physical changes that result from certain drugs taken for pleasure, such as ecstasy. The user sweats profusely, due to prolonged over activity then dehydration develops leading to heat exhaustion. These effects coupled with the drug’s effect of the temperature regulating centre of the brain can lead to heatstroke and even cause death.

Recognition

Recognition features may include:

• Headache.
• Dizziness and confusion.
• Loss of appetite.
• Nausea.
• Sweating with pale clammy skin.
• Cramps in the arms, legs and the abdominal wall.
• Rapid, weakening pulse.
• Rapid, shallow breathing.

Treatment

Your aims are to replace any lost body fluids and salt; to cool the casualty down, if necessary, and to obtain medical help.

• Help the casualty to a cool place.
• Get them to lie down with their legs raised.
• Give them plenty of water.
• Follow if possible with a weak salt solution - 1 teaspoon of salt per litre of water, assist the casualty to drink it.
• Even if the casualty recovers quickly, ensure that they see a doctor.
• If the casualty’s responses deteriorate place them into the recovery position and dial 999 or 112 for an ambulance.
• Monitor and record any vital signs – the level of response, the pulse and breathing rate.
• Be prepared to give rescue breaths and chest compressions if necessary

6. Frostbite

With frostbite the tissues of the extremities – usually the toes and the fingers – freeze due to low temperatures. In severe cases, it can lead to a permanent loss of sensation and, eventually, tissue death (gangrene) as the blood vessels become irreversibly damaged.

Frostbite usually occurs in freezing or windy and cold conditions. People who cannot move around are particularly susceptible. In many cases frostbite is accompanied by hypothermia and this should be treated accordingly.

Recognition features

There may be:

• ‘Pins and needles’ to begin with.
• Pallor followed by numbness.
• Hardening and stiffening of the skin.
• A colour change to the skin of the affected area: first white, then mottled and blue. On recovery, the skin may be red, hot, painful and blistered. Where gangrene occurs, the tissue may become black due to the loss of blood supply.

Treatment

If possible move the casualty into the warmth before you thaw the affected part.

Gently remove rings, gloves and any other constrictions such as boots. Warm the affected part with your hands on your lap, or under the casualty’s armpits. Rubbing the affected areas must be avoided as this can damage the skin and other tissues.

Place the affected part in warm water at around 40°C (104°F). Dry carefully, and apply a light dressing of fluffed-up, dry gauze bandage.

Support and raise the affected limb to reduce swelling. An adult casualty may take two paracetamol tablets for intense pain. Take or send the casualty to hospital.

Warning

Do not:

• put the affected part near direct heat
• attempt to thaw the affected part if there is a danger of it refreezing
• allow the casualty to smoke.

7. Hypothermia

Hypothermia develops when the body temperature falls below 35°C (95°F). The effects vary depending on the speed of the onset and the level to which the body temperature falls. Moderate hypothermia can usually be completely reversed.

Severe hypothermia – when the core body temperature falls below 30°C (86°F) – is often, but not always fatal. However, no matter how low the body temperature is, it is always worth persisting with life-saving procedures until a doctor arrives to assess the casualty.

Recognition features

There may be:

• Shivering and pale, cold, dry skin.
• Disorientation, apathy or irrational behaviour; occasionally belligerence.
• Impaired consciousness or lethargy.
• Slow and shallow breathing.
• Slow and weakening pulse.
• In extreme cases the heart may stop.

Treatment

For a casualty who has been brought in from outside, immediately replace wet clothing with warm, dry garments.

The casualty can be rewarmed by bathing if they are fit, young and able to climb into a bath unaided. The water should be warm but not too hot – about 40°C (104°F).

Put the casualty in a bed and ensure that they are well covered. Give them warm drinks or high energy foods such as chocolate to help rewarm them.