Advanced Trauma Life Support ATLS Student Course Manual 2018

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CHAPTER 9 n Thermal Injuries
local infection, cellulitis, lymphangitis, and gangrene
can occur. Proper attention to foot hygiene can prevent
the occurrence of most such complications.
Management of Frostbite and
Nonfreezing Cold Injuries
n FIGURE 9-8 Frostbite. Frostbite is due to freezing of tissue with
intracellular ice crystal formation, microvascular occlusion, and
subsequent tissue anoxia.
3. Third-degree frostbite: Full-thickness and
subcutaneous tissue necrosis occurs, commonly
with hemorrhagic vesicle formation.
4. Fourth-degree frostbite: Full-thickness skin
necrosis occurs, including muscle and bone with
later necrosis.
Although the affected body part is typically hard, cold,
white, and numb initially, the appearance of the lesion
changes during the course of treatment as the area
warms up and becomes perfused. The initial treatment
regimen applies to all degrees of insult, and the initial
classification is often not prognostically accurate. The
final surgical management of frostbite depends on
the level of demarcation of the perfused tissue. This
demarcation may take from weeks to months to reach
a final stage.
Nonfreezing Injury
Nonfreezing injury is due to microvascular endothelial
damage, stasis, and vascular occlusion. Trench foot or
cold immersion foot (or hand) describes a nonfreezing
injury of the hands or feet—typically in soldiers, sailors,
fishermen, and the homeless—resulting from longterm
exposure to wet conditions and temperatures
just above freezing (1.6°C to 10°C, or 35°F to 50°F).
Although the entire foot can appear black, deeptissue
destruction may not be present. Alternating
arterial vasospasm and vasodilation occur, with the
affected tissue first cold and numb, and then progress
to hyperemia in 24 to 48 hours. With hyperemia comes
intense, painful burning and dysesthesia, as well as
tissue damage characterized by edema, blistering,
redness, ecchymosis, and ulcerations. Complications of
Treatment should begin immediately to decrease the
duration of tissue freezing. Do not attempt rewarming
if there is a risk of refreezing. Replace constricting,
damp clothing with warm blankets, and give the patient
hot fluids by mouth, if he or she is able to drink. Place
the injured part in circulating water at a constant
40°C (104°F) until pink color and perfusion return
(usually within 20 to 30 minutes). This treatment is best
accomplished in an inpatient setting in a large tank,
such as a whirlpool tank, or by placing the injured limb
into a bucket with warm water running in. Excessive
dry heat can cause a burn injury, as the limb is usually
insensate. Do not rub or massage the area. Rewarming
can be extremely painful, and adequate analgesics
(intravenous narcotics) are essential. Warming of
large areas can result in reperfusion syndrome, with
acidosis, hyperkalemia, and local swelling; therefore,
monitor the patient’s cardiac status and peripheral
perfusion during rewarming.
Local Wound Care of Frostbite
The goal of wound care for frostbite is to preserve
damaged tissue by preventing infection, avoiding
opening uninfected vesicles, and elevating the injured
area. Protect the affected tissue by a tent or cradle, and
avoid pressure to the injured tissue.
When treating hypothermic patients, it is important
to recognize the differences between passive and active
rewarming. Passive rewarming involves placing the
patient in an environment that reduces heat loss (e.g.,
using dry clothing and blankets), and relies on the
patient’s intrinsic thermoregulatory mechanism to
generate heat and raise body temperature. This method
is used for mild hypothermia. Active rewarming
involves supplying additional sources of heat energy
to the patient (e.g., warmed IV solution, warmed
packs to areas of high vascular flow such as the groin
and axilla, and initiating circulatory bypass). Active
rewarming is used for patients with moderate and
severe hypothermia.
Only rarely is fluid loss massive enough to require
resuscitation with intravenous fluids, although patients
may be dehydrated. Tetanus prophylaxis depends on
the patient’s tetanus immunization status. Systemic
antibiotics are not indicated prophylactically, but are
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