COLD INJURIES - Medicine for Mountaineering and Other Wilderness Activities - page 398

hypothermic individuals should be declared dead unless their measured body temperature
hasfallentoenvironmentallevels.Onlyafterunsuccessfulrewarmingcandeathbecertain.
No one should be considered cold and dead until he has been warm and dead!
TREATING MILD HYPOTHERMIA
Recognizing mild hypothermia is critical. Its treatment is simple: “All those things your
mother told you to do when you went outside in the cold.” Effective measures decrease
heat loss and increase heat production.
Decreasingheatlossbyconvectioncanbeachievedbyputtingonmoreclothing:sweat-
ers, caps, mittens, jackets, parkas, windpants, or whatever is available. Protection from the
wind by parkas or windpants, rocks or trees, natural shelters such as caves or even cre-
vasses,orshelterssuchascabins,tents,orsnowcavesreducesconvectiveheatlossorwind
chill. Replacing wet clothing with dry clothing restores insulation and reduces evaporative
heat loss. The warmer environment provided by a fire—or just body heat within a wind-
proof shelter—reduces radiant heat loss.
Heatproductioncanbeincreasedsignificantly.Shiveringisaninvoluntarymuscleactiv-
ity that generates heat at a rate equivalent to walking fast. More heat can be generated by
vigorously exercising the large muscles in the legs and back if the individual is not shiver-
ing uncontrollably. Such exercise is even more useful if it helps a hypothermic person get
outofahostileenvironment.However,ifescapefromthepredicamentisnotpossible,then
purposeless exercise, such as repeatedly stepping up onto a stone or log, can generate heat.
A metabolic energy source—food—is needed if increased heat production is to be main-
tained.
Heat-producing exercise cannot be continued indefinitely. Nor can enough heat be pro-
duced by exercise to compensate for the large quantity of heat lost in cold water or in a
snowstorm if the individual is inadequately protected.
Once hypothermia has been corrected, measures to prevent its recurrence are essential.
It would probably recur faster because energy stores would be depleted. A rewarmed per-
son must not be returned to the hypothermia-inducing environment without additional pro-
tection.
TREATING MODERATE AND SEVERE HYPOTHERMIA
Moderate and severe hypothermia are complex disorders for which the simple measures
that effectively treat mild hypothermia are inadequate because severely hypothermic indi-
viduals cannot generate enough heat to rewarm themselves. An external heat source must
beprovided.Inaddition,ventricularfibrillationmustbeavoidedwhiletheindividualisbe-
ing rewarmed.