|
Exposing the body
to severe cold can lead to lowering of the body’s core temperature. This
condition is known as hypothermia.
Moisture on the skin, such as sweating, leads to evaporation: the most
potent source of cooling. Unlike heat exposure, the body has only limited
ability to acclimatise to cold. Shivering is the only source of
short-term protection so appropriate clothing is the main form of
prevention.
Incidence
Most common in those least prepared to meet the possibility of cold stress.
Symptoms
Mild
Core body
temperature:
- 37°-35°C
Sensation of chilliness, skin numbness, minor impairment in muscular
performance particularly fine hand movements, shivering begins.
- 35°-34°C
More obvious lack of muscle coordination and weakness, slow
stumbling walk, mild confusion and apathy.
- 34°-32°C
Gross loss of muscular coordination with frequent stumbling,
inability to use hands, slow thought and speech.
Severe
Core body
temperature:
- 32°-30°C
Shivering ceases, severe loss of muscular coordination with
stiffness and inability to walk or stand, incoherent, confused,
irrational behaviour.
- 30°-28°C
Severe muscular rigidity, semiconscious state, pupils dilate,
unapparent heart beat and breathing.
<28°C
- Unconsciousness,
death.
Prevention
Hypothermia can be a gradual process and may take hold before you realise
it. It’s important to recognise when you might be a risk and take steps
to prevent it.
- Know your
environment and be prepared.
- Be attentive to
yourself and your companions. Hypothermic individuals often behave
inappropriately.
- Take wind and
rain gear.
- Stay dry.
- Wear layers of
clothing, taking off layers before sweating starts and adding them
back before chilling occurs.
- Wear an inner
layer such as polypropylene that will wick moisture away from the
skin
- Buy high
quality gloves and socks (layered to wick moisture away from the
skin) to reduce the risk of frostbite.
- Heat is lost
from radiation through your head; wear a warm hat that covers the
ears.
- Ensure adequate
hydration.
- Eat regularly -
food generates heat.
Treatment
- Recognise the
early signs (fine motor shivering, apathy) and treat immediately.
- Change the
environment if possible; find shelter.
- Replace wet
clothing with dry clothing, add wind and waterproof layers.
- Add insulation
under and around the patient; aim to stop further heat loss.
- Encourage
exercise; give warm sweet non-caffeinated, non-alcoholic liquids and
food.
Shivering
The body can only increase heat production to a limited extent. Shivering
is an involuntary muscle action that produces about the same amount of
heat as fast walking. Using our larger muscles, especially those of the
legs, generates heat. However there is a limit to how long this activity
can be sustained. Avoiding potentially hazardous situations and ensuring
adequate preparation are far more effective methods of staying warm.
Frostbite
Frostbite is an injury produced by freezing of body tissues. It usually
affects the hands, feet, face and ears. The early signs of frostbite are
sensations of cold or pain and paleness of the skin. As the tissues begin
to freeze the pain disappears. The tissue will increasingly become whiter
and harder.
It is difficult to assess the severity of frostbite until some thawing
has occurred. Rapid re-warming in a large water bath is the best
treatment. This should be performed in a hospital.
Note: the greatest damage occurs when frost bitten tissues are thawed and
then refrozen. It is best to avoid treatment by people unfamiliar with
this situation.
Severe Hypothermia treatment
This is a complex and very serious condition. Warm the patient with dry
clothes, blankets and body heat and seek urgent medical attention.
Rubbing of extremities or applying heat is very dangerous. Avoid movement
if possible as bumps and jolts can trigger a lethal irregularity of
heartbeat. Heating of the central body (heart, lungs) is required and
this can only be achieved in a hospital setting.
More information on cold stress is available during your
pre-travel consultation with Travelvax. Call 1300 360 164 for the
location of the clinic nearest to you.
|