Heat dissipation(loss)

•( radiation)

•( convection)

• ( conduction)

•( evaporation)

Classifications for by extreme cold 

• Frost nip is a superficial cooling of tissues without cellular destruction

• Chilblains are superficial ulcers of the skin that occur when a predisposed individual is repeatedly exposed to cold

• Frostbite involves tissue destruction

Frostbite

• Frostbite is the medical condition where localized damage is caused to skin and other tissues due to freezing.

• Frostbite is most likely to happen in body parts farthest from the heart and those with large exposed areas. The initial stages of frostbite are sometimes called "frost nip"

Sign• At or below 0 °C (32 °F), blood vessels close to the skin start

to constrict, and blood is shunted away from the extremities via the action of glomus bodies.

• The same response may also be a result of exposure to high winds.

• This constriction helps to preserve core body temperature. • In extreme cold, or when the body is exposed to cold for long

periods, this protective strategy can reduce blood flow in some areas of the body to dangerously low levels.

• This lack of blood leads to the eventual freezing and death of skin tissue in the affected areas.

• There are four degrees of frostbite. Each of these degrees has varying degrees of pain

• If rewarmed tissue ends up refreezing, more damage to tissue will be done.

• Excessive movement of frostbitten tissue can cause ice crystals that have formed in the tissue to do further damage.

• Splinting and/or wrapping frostbitten extremities are therefore recommended to prevent such movement.

• For this reason, rubbing, massaging, shaking, or otherwise applying physical force to frostbitten tissues in an attempt to rewarm them can be harmful

• Warming can be achieved in one of two ways:

Active &Passive rewarming• Passive: involves using body heat or ambient room temperature

to aid the person's body in rewarming itself. • This includes wrapping in blankets or moving to a warmer

environment.• Active : direct addition of heat to a person, usually in addition to

the treatments included in passive rewarming.• Active rewarming requires more equipment, and therefore may

be difficult to perform in the prehospital environment.• When performed, active rewarming seeks to warm the injured

tissue as quickly as possible without burning. • This is desirable as the faster tissue is thawed, the less tissue

damage occurs.[5] Active rewarming is usually achieved by immersing the injured tissue in a water-bath that is held between 40-42°C (104-108F).

Heat illness• body temperature of greater than 40.6 °C (105.1 °F)

• Symptoms :dry skin, rapid, strong pulse and dizziness.

• Heat exhaustion - heavy sweating, rapid breathing and a fast, weak pulse.

• Heat syncope - Fainting as a result of overheating

• Heat edema• Heat cramps - Muscle pains that happen

during heavy exercise in hot weather.• Heat rash - Skin irritation from excessive

sweating.

protection• Avoid outdoor activity during excessive heat• Drink plenty of fluids when working

outdoorsDuring outdoor activity,• splash your body frequently with water• Avoid alcohol / coffee / soda / alcohol Wear light weight, light- colored, loose-fitting clothes• Protect yourself from the sun by wearing sun glasses and hat

First aid

• Remove the person to a shady place• Cool the person by sponging with wet towel or…

• Apply ice packs in armpits and groin• Water with electrolyte, fruit / vegetable juice

should be given Victim must be rested

• The person is turned on their back with a secure grip used to tow from behind.

• If the person is cooperative they may be towed in a similar fashion held at the armpits.

• If the person is unconscious they may be pulled in a similar fashion held at the chin and cheeks, ensuring that the mouth and nose are well above the water.

• "C-A-B-" Treatment for hypothermia may also be necessary.

• The Heimlich maneuver is not recommended• Performing the maneuver on drowning

people not only delays ventilation but may induce vomiting

Drowning

Copyright © 2007, 2003 by Mosby, Inc., an affiliate of

Elsevier Inc . Slide 16

• Drowning is the process of experiencing respiratory impairment from submersion/immersion in liquid. event involving

• can lead to serious secondary complications or death, possibly up to 72 hours after the event

• occurs more frequently in males and the young

• A person drowning is unable to shout or call for help, or seek

Cold water immersion• Rescue involves bringing the

person's mouth and nose above the water surface.

• If the rescuer does get pushed under water, they should dive downwards to escape the person.

• After a successful approach, negatively buoyant objects such as a weight belt are removed.

• The priority is then to transport the person to the water's edge in preparation for removal from the water.

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