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Environmental emergencies are medical conditions caused or worsened by the
weather, terrain, or unique atmospheric conditions such as high altitude or being
underwater.
Risk factors that predispose people to environmental emergencies include being
very young, being elderly, being in a poor state of health, and taking certain
medications.
Thermoregulation is the body’s ability to ensure a balance between heat
production and elimination. The hypothalamus is the organ involved in regulating
this balance. The skin also has a major role.
The body produces heat through metabolism. The basal metabolic rate (BMR) is
the heat energy produced at rest from normal metabolic reactions. Metabolism can
be increased through exertion, which also creates body heat. Absorption of heat
from the environment can also occur.
Thermolysis is the release of heat and energy from the body. Thermogenesis is the
production of heat and energy for the body.
The body has four main means of cooling itself: radiation—transfer of heat to the
environment; conduction—transfer of heat to a cooler object through direct
contact; convection—loss of heat to air moving across the skin; and
evaporation—conversion of liquid to a gas (sweating).
Heat illness is the increase in core body temperature due to inadequate
thermolysis; the body cannot get rid of a heat buildup.
Heat cramps are acute, involuntary muscle pains in the abdomen or lower
extremities resulting from profuse sweating and sodium loss. The patient’s pulse
is usually rapid, the skin pale and moist, and the temperature normal. Treatment
includes moving the patient to a cool environment, providing a salt-containing
solution if the patient is not nauseated, or administering IV normal saline.
Heat syncope can occur when an overheated patient suddenly changes position.
Treatment includes placing the patient supine and replacing fluids.
Heat exhaustion can result from dehydration and heat stress. Symptoms include
headache, fatigue, dizziness, nausea, vomiting, and abdominal cramping. Skin is
usually pale and clammy, and heart rate and respirations are rapid. Treatment
consists of removing the patient from heat and providing fluids through sports
drinks or an IV line.
Heat stroke is defined as a core temperature above 104°F and altered mental
status. Signs include changes in behavior, nervous system disturbances (such as
tremors), elevated temperature, tachycardia, hyperventilation, and skin that is dry
and red or pale and sweaty. Treatment is to remove the patient from the heat,
perform cooling measures, administer normal saline, and monitor the cardiac
rhythm.
Fever can mimic heat stroke. Take a thorough history, and treat for heat stroke if
in doubt.
To prevent heat illness, dress appropriately, stay hydrated, and stay in the shade or
air conditioning. Community-based programs aimed at high-risk populations can
provide valuable education.
Frostbite is local freezing of a body part; it is classified as superficial or deep.
Frostnip is a very mild form of frostbite.
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Superficial frostbite is characterized by numbness, tingling, or burning. The skin
is white, waxy, and firm to palpation. When thawed, the skin turns cyanotic and
the patient feels a hot, stinging sensation. Treatment is getting the patient out of
the cold; rewarming the injured part with body heat; covering with a warm, sterile
dressing; and transporting the patient.
In deep frostbite, the injured body part looks white, yellow-white, or mottled
blue-white and is hard, cold, and without sensation. Major tissue damage can
occur when the part thaws. Gangrene (permanent cell death) can result in the need
for amputation. Treatment includes leaving the part frozen if it is found frozen, or
rewarming the part if it is partially thawed.
Trench foot is similar to frostbite but results from prolonged exposure to cool, wet
conditions. Prevention is the best treatment.
Hypothermia is a decrease in core body temperature. It can be mild, moderate, or
severe.
Mild hypothermia is a core body temperature of greater than 93°F. The patient
shivers and may be confused, have slurred speech, or have impaired coordination.
Treatment is passive rewarming such as removing wet clothing or drying the
patient’s skin and possibly providing warm fluids.
Moderate hypothermia is a core body temperature in the range of 86°F to 93°F.
Treatment is passive rewarming, active external rewarming of truncal areas,
administering warmed IV fluids, and potentially using special rewarming devices.
Severe hypothermia is a core body temperature less than 86°F. Treatment is active
internal rewarming, such as administering warm IV fluids, and in-hospital
measures.
Hypothermic patients who are not breathing or who do not have a pulse need
resuscitation. Patients in cardiac arrest require high-quality CPR and possibly a
single shock depending on the heart rhythm. Attempt to insert an advanced
airway; deliver ventilation with warm, humidified oxygen; and provide IV fluids.
Hypothermic patients with obvious lethal traumatic injuries or patients who are so
frozen as to block the airway or chest compression efforts generally are dead. If
the patient appears dead after prolonged exposure, hypothermia may protect the
brain and organs. Resuscitation can be attempted in cases of cardiac arrest and
hypothermia.
Drowning or submersion is the process of experiencing respiratory impairment
from submersion or immersion in liquid. Drowning progresses from breath
holding, to laryngospasm, to respiratory and cardiac arrest.
Caring for a submersion patient starts with reaching the patient, a task that should
be undertaken by specially trained rescuers. Treatment includes caring for the
ABCs and taking cervical spine precautions. Positive end-expiratory pressure may
be used to keep the alveoli open and drive fluid out. A nasogastric tube may be
inserted to decompress the stomach if the patient is intubated. Submersion
patients may develop bronchospasm and may require administration of a beta-2
adrenergic drug.
In diving injuries, obtain as many details as possible about the patient, including
the type of diving, type of tank, number of dives in the past 72 hours, and predive
and postdive activities.
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Barotrauma can result during dive descent, owing to a pressure imbalance
between the inside of the body and the outside atmosphere. It may result in ear
pain. Treatment is a loose dressing for ear bleeding, plus possibly IV antiemetics
or sedatives.
Nitrogen narcosis is a state of altered mental status caused by breathing
compressed air at depth. Signs and symptoms include feeling euphoric; exhibiting
inappropriate, foolish behavior; and tingling of lips, gums, and legs.
When a diver ascends too quickly, pulmonary overpressurization syndrome
(POPS, also known as burst lung) can occur. Signs and symptoms include
mediastinal and subcutaneous emphysema, a sense of fullness in the throat, pain
on swallowing, dyspnea, and substernal chest pain.
Arterial gas embolism is a dangerous consequence of POPS. Air bubbles may
travel to the coronary arteries, causing cardiac arrest. Symptoms include weakness
or paralysis of the extremities, seizure activity, unresponsiveness, and other
neurologic symptoms.
Treatment of barotrauma depends on whether an air embolism is present. A
pneumothorax may require needle decompression. With an air embolism, the
patient must receive treatment in a hyperbaric chamber.
Decompression sickness encompasses a broad range of signs and symptoms
caused by nitrogen bubbles in blood and tissues coming out of solution on dive
ascent. Symptoms include itchy skin, subcutaneous emphysema, swelling, rashes,
joint and muscle pain, sensory and motor disturbances, incoordination, paralysis,
chest pain, and dyspnea. Treatment is 100% oxygen, IV normal saline, and
transport to a hyperbaric facility.
Shallow water blackout occurs when a person hyperventilates just before diving
underwater and passes out before resurfacing. Treatment is the same as for any
other submersion.
The Divers Alert Network is a valuable resource for diving-related injuries.
Callers are immediately connected to a physician experienced in diving medicine
who can provide advice regarding specific management.
Altitude illness occurs when unacclimatized people ascend to altitude. Types of
altitude illness include acute mountain sickness (AMS), high-altitude cerebral
edema (HACE), and high-altitude pulmonary edema (HAPE).
Symptoms of AMS include headache plus fatigue, weakness, gastrointestinal
symptoms, dizziness, lightheadedness, and difficulty sleeping.
Symptoms of HACE include a change in mental status and/or ataxia in a person
with AMS or the presence of both in a person without AMS.
Symptoms of HAPE include at least two of the following: dyspnea at rest, cough,
weakness, or chest tightness or congestion and at least two of the following:
central cyanosis, audible rales, wheezing, tachypnea, or tachycardia.
Treatment of altitude illnesses includes descending or using a portable hyperbaric
chamber, providing oxygen, and giving certain IV medications.