COLD INJURIES - Medicine for Mountaineering and Other Wilderness Activities - page 400

devices that remove blood from the body, warm it, and return it are only needed for indi-
viduals who do not have effective cardiac function and must be rewarmed rapidly.
However, experience has demonstrated that central rewarming is not essential for most
individuals who have functioning hearts. They have gotten hypothermic slowly and can be
rewarmed slowly. Many hospitals that commonly treat hypothermic individuals, which in-
cludes most northern and high-altitude U.S. areas, rely primarily on external forced-air re-
warming devices such as the Bair Hugger® combined with recirculating water mattresses.
The development of wilderness rewarming techniques has met with limited success.
Two components are essential:
◆ Protection from the environment
◆ External rewarming
Protection from the environment can be achieved by placing the individual in a tent and
in a sleeping bag. To avoid precipitating ventricular fibrillation, an insulating pad should
be gently slipped under the person, who then can be carefully placed in a sleeping bag and
slid into a tent. (The sleeping bag only insulates the person; the body is producing so little
heatthatthesleepingbagdoesnotrewarmtheperson.)Toreduceheatlossduetowarming
and humidifying inhaled cold air in the lungs, the air within the tent can be warmed and
humidified by boiling water on a portable stove.
External rewarming transfers so little heat that all available techniques must be em-
ployed. One rewarming method is to place folded sheets or blankets soaked in hot water
and placed in plastic bags, hot-water bottles, or similar warming devices along the sides of
theneckandchestwherethebodywallisthin.(Obviously,ifenoughwarminginstruments
are available, they can be placed anywhere.) Hot-water bottles and similar devices must
not be so hot they burn the person. They should be wrapped in fabric and the temperat-
ure checked by holding them under the arm of a person with normal temperature for a full
minute.
The most effective portable device for external rewarming is a charcoal heater, which
should be carried by rescue teams. It contains a slowly burning charcoal fuel canister and a
fanthatcirculatesthegeneratedheatthroughflexibletubing.Itdistributes250wattsofheat
directly to the skin for eight to twelve hours and requires only a D-cell battery to power
the fan. Obviously extra fuel and batteries—and more than one warming device—can be
carried.
Placing a normothermic individual in the sleeping bag with a hypothermic person trans-
fers only a minimal amount of heat through body-to-body contact. Heated, humidified aer-
osols also transfer only a minimal amount of heat.
Severely hypothermic individuals are inevitably dehydrated, and all benefit from cor-
rection of the dehydration. Since most are unable to ingest fluids orally, rehydration fluids
must be given intravenously. However, the peripheral veins of a dehydrated, severely hy-