COLD INJURIES - Medicine for Mountaineering and Other Wilderness Activities - page 405

cardiac work—or rough handling—may induce arrest or fibrillation of a cold heart. If pos-
sible a person should be gently removed from the water in a horizontal position.
Death may also occur within minutes to hours after rescue. A rescued individual may
beseverelycompromisedbyacidicmetabolic by-productsaccumulating intheextremities,
a heart prone to dysrhythmias, decreased or absent consciousness, and low blood volume.
Sudden redistribution of blood to the extremities, particularly the lower extremities, may
cause collapse as a result of decreased blood pressure, sudden return of metabolites to an
irritable heart, or continued decrease in temperature (afterdrop) of an unstable heart. In ad-
dition, individuals often aspirate water during long periods of immersion, which may pro-
duce delayed lethal hypoxia because gas exchange in the lungs is compromised.
Wet clothing becomes a major source of heat loss. Rescued individuals with immersion
hypothermia may be warmer with no clothes on, particularly if they can be protected from
the wind. In any case, wet clothing should be removed at least temporarily and as much
water wrung out as possible.
Staying Alive
If a person survives the initial stages of cold water immersion, heat loss must be min-
imized, and energy must be conserved. Large people cool more slowly than small people;
fat people cool more slowly than thin people; children cool more rapidly than adults.
Activity also affects core cooling. Exercise heat production can almost never equal the in-
creased heat loss to the water caused by increased peripheral blood flow and limb move-
ment through cold water. Water has high heat conductivity and drains heat from the body
twenty-five times faster than air at the same temperature.
If no flotation is worn, valuable energy is lost keeping the head above water. Survival
dependsonswimmingtosafetyorobtainingsomeotherformofflotation.Whenswimming
ortreadingwater,apersoncoolsmuchfasterthanwhenremainingstill,andcoldincapacit-
ation eventually results in swimming failure.
If a PFD is worn, it has the immediate benefit of maintaining a person's airway without
the effort of swimming. It can keep even an unconscious person afloat. An average-size
person wearing lightweight clothing and a PFD may survive three to six hours in 50°F
(10°C) water by remaining still.
Duringcoldwaterimmersion,morethan95percentoftheheatlossistothewater.Since
most boats float even when capsized or swamped, getting into or onto the boat to get as
far out of the water as possible is usually advisable. If the body cannot be raised out of the
water, the Heat Escape Lessening Position (H.E.L.P.) can be adopted.
A group of immersed individuals should keep together for psychological support and
possiblyforincreasedthermalinsulation.Thegroupmaytrytoadoptahuddleposition,but
it can be difficult to maintain in rough water because some in the group have their backs to
the waves and movement through the water is limited. At the very least, individuals should