Humans, like all the warm – blooded species, must maintain the body temperature within a pre-defined optimal range for the bodily systems to function effectively. Thermoregulation mechanisms maintain an average core temperature of 370C (98.6 0F) balancing the generation and loss of heat in human body under normal circumstances.
Upon exposure to cold environments for prolonged periods the heat loss from the body may exceed the heat generation capacity causing core temperature to decline. When core temperature falls below 350C (950F), it is called hypothermia. Unless intervened urgently, organ systems begin to progressively fail until death occurs due to cardiac arrest.
Infants and elderly (poorly cared) are more at risk to develop hypothermia as they are unable to control heat loss and generation effectively. Hypothermia can develop acutely (e.g. falling into icy water) or it may be a gradual and insidious process.
Causes of hypothermia
• Environmental: – exposure to cold, wet or windy conditions, immersion/submersion in cold water.
• Drugs: – alcohol or sedatives.
• Burns (loss of protection from skin).
• Trauma and immobility.
• Endocrine: – hypothyroidism
• Neurological: – stroke, dementia, altered consciousness, Alzheimer’s disease
• Malnutrition and severe infections.
Signs and symptoms of hypothermia
• Mild hypothermia
- Pale and cool skin.
- Shivering
- Impaired coordination
- Drowsiness, exhaustion and confusion
- Slurred speech
• Moderate/severe hypothermia
- Progressive decline and loss of consciousness
- Absence of shivering
- Muscle stiffness
- Slow irregular pulse
- Abnormally slow breathing
- Body temperature < 350C
- Hypotension
- In infants – bright red, cold skin
- Cardiac arrest
First aid management
1. Call emergency medical services.
2. Quickly asses the vital conditions of the patient; breathing, pulses and level of consciousness. Continue assessment until medical help arrives.
3. If patient is not breathing (or seems dangerously low or shallow) and/or have absent/weak pulses; attend to basic life support, establish the airway and commence CPR. Continue till recovery or help arrives.
4. Remove from the cold environment. If not possible cover the head, protect from wind and insulate from cold ground.
5. Remove sources of heat loss such as wet clothing, dry the victim and cover with warm and dry coverings.
6. Remember not to remove the victims clothing even when they are wet if you do not have suitable cover. Doing so will accelerate heat loss from the body.
7. If the victim is in a remote location and not shivering, rescuer must initiate active rewarming using external heat, either body to body contact or a heat source.
8. Begin rewarming from the trunk of the victim, not the hands and feet. Warming extremities will divert cold back to heart and brain further dropping core temperature as well as patient may go into shock.
9. If using hot water bottles or heat packs, wrap them in a cloth; do not apply directly on to skin as it will cause burns.
10. Do not immerse victim in hot water as rapid rewarming of hypothermic victim can cause cardiac arrhythmias.
11. If the patient is conscious give a warm drink; avoid alcohol or caffeine.
12. Do not massage or rub the patient as their skin may be frostbitten. Handle these victims carefully.
13. Once the body temperature begins to rise, keep the victim wrapped in dry and warm clothes/blankets. Wrap the person’s head and neck as well.