-- The Silent Killer
By Gary Ross,
It's August now. The last
of the summer warmth. Days grow shorter. Autumn is near, and then winter...
This segment is on hypothermia.
Hypothermia is condition of general body cooling (in contrast to frostbite
which is localized). It can kill you. But do not let the introduction
mislead you. Hypothermia generally occurs during cold weather, but it
can occur at any temperature (but generally below 60 degrees).
Three factors are major
causal factors in hypothermia: cold, water, and wind.
1) In a cold environment,
the body must work harder to regulate heat; contact with cold air, water,
snow, ground or clothing will cause heat losses due to conduction.
2) If a person is submersed
in water, heat will be lost due to conduction and convection. At a water
temperature of 32 degrees death occurs in 15 minutes; at 70 degrees survival
for as long as 48 hours has been observed. Loss of heat by evaporation
is a major contributor also. Wet skin or clothing will cool of the body
quickly, especially if it is windy and/or cold.
3) Wind will cause heat
loss due to convection, and will accelerate heat loss due to evaporation.
4) Hypothermia occurs much
more quickly in the elderly and chronically ill.
Hypothermia is insidious.
As the body's core temperature drops, more and more body systems suffer
from the effects of cold. The presence and severity of hypothermia can
be assessed by the signs and symptoms below. A patient is hypothermic
at any temperature below 98.6 degrees fahrenheit (rectal). 98-94 degrees
is mild hypothermia; 94-84 degrees is moderate hypothermia, and below
84 degrees is severe hypothermia.
STAGES OF HYPOTHERMIA:
98 - 95 degrees - Sensation
of chilliness, skin numbness; minor impairment in muscular performance,
especially in use of hands; shivering begins.
95 - 93 degrees - More
obvious muscle incoordination and weakness; slow stumbling pace; mild
confusion and apathy. Skin pale and cold to touch.
93 - 90 degrees - Gross
muscular incoordination with frequent stumbling and falling and inability
to use hands; mental sluggishness with slow thought and speech; retrograde
90 - 86 degrees - Cessation
of shivering; severe muscular incoordination with stiffness and inability
to walk or stand; incoherence, confusion, irrationality.
86 - 82 degrees - Severe
muscular rigidity; patient barely arousable; dilatation of pupils; inapparent
heartbeat and pulse. Skin ice cold.
82- 78 degrees and below
- Unconsciousness; death due to cessation of heart action.
TREATMENT OF HYPOTHERMIA:
Two situations are possible.
One is where evacuation to a medical facility is possible within several
hours. The other is where evacuation will be delayed or impossible. The
other parameter is stage of hypothermia.
Get the patient as sheltered
as possible (tent, snow cave, etc.) Remove wet clothing and replace with
dry clothing. Keep patient laying down. Place patient in a sleeping bag
with a second rescuer of normal body temperature. Direct skin to skin
contact is preferable. Warm stones or bottles can also be placed in the
bag (be careful not to burn patient). Make sure all extremities and exposed
areas (e.g. face, nose, ears) are protected. If patient is conscious and
able to swallow without danger to his/her airway, give sugar and sweet,
warm (not hot) fluids by mouth. DO NOT GIVE ALCOHOL. If evacuation is
IMPOSSIBLE and facilities permit, immerse patient in tub of water at 105
degrees Fahrenheit. Monitor patient's temperature rectally with thermometer
if possible. Continue rewarming efforts until patient's core temperature
is restored to normal. Always evacuate a hypothermic patient as quickly
and gently as possible, including rewarmed patients.
Patients in severe hypothermia
are often erroneously thought to be dead. Neither pulse, nor heart sounds,
nor respirations may be apparent. Handle a severely hypothermic patient
with great care - VERY GENTLE HANDLING. Cut away wet clothing and replace
with dry clothing. Maintain an airway, but use no adjuncts (e.g. oral
airway). Once you start CPR, DON'T GIVE UP. Get help. Do not attempt to
rewarm patient unless evacuation is IMPOSSIBLE. Keep patient supine, in
a 10 degree head-down tilt.
Handle every hypothermic
patient very gentle. Rough handling can cause cardiac arrest and death.
Get every patient into shelter, replace wet clothes with dry ones. Apply
external heat if condition dictates. And give warm, sugary food and drink
if patient's condition allows. Get help. If possible, have rescuers bring
a heated oxygen unit, and administer to patient. Perhaps equipment can
be air-dropped. Keep calm and do not become a victim yourself.
THE HYPOTHERMIC PATIENT
ISN'T DEAD UNTIL HE'S WARM AND DEAD.
PREVENTION OF HYPOTHERMIA:
Dress properly for current
and possible conditions. Be prepared for sudden weather changes especially
at elevations. Have at least one wool garment for the upper and lower
parts of your body. Wool is the only material with any insulating value
when wet. Carry or wear a windproof, waterproof garment. Always have a
wool hat and wool mittens. Have extra clothing available especially mittens
and hats. A large proportion of body heat is lost through the head. Wear
suitable boots, insulated if necessary; wear wool socks, and always carry
extra wool socks. Avoid getting overheated and perspiring, this cools
you down - fast. Wear layers and remove clothing as necessary. Better
having extra than too little. Dress sensibly and expect the worst.
Sit out bad weather. Better
waiting than be overtaken by a blizzard or thunderstorm. Do not push on
through the night. Make camp early and rest thoroughly. You can continue
tomorrow with a much greater safety margin.
Do not get exhausted. Exhaustion
promotes heat loss, and thus hypothermia. Besides, if your exhausted,
you are probably drenched.
Do not get in over your
head. If your experience is limited to day hikes on moderate trails, do
not try to go out and tackle Mt. Washington in February. Be smart. Learn
to use a map and compass. Learn fire starting techniques. Learn first-aid.
Be calm. Be prepared.
Lastly, learn about hypothermia.
Know the causes, warning signs, and treatment. Learn how not to get cold.
NOTE: Special hypothermia
thermometers are available which measure between about 70 and 100 degrees
Fahrenheit. I recommend carrying one in your first-aid kit on all cold
weather excursions. Contact me for information on where you can purchase
I hope you found this information
useful and important and feel free to contact me if you have any questions.
Have fun in the great outdoors, but be careful. Mother Nature is never
malicious, just incredibly powerful.
Gary Ross, EMT-D