Chapter 15
Physical and Environmental Hazards
Lesson Objectives (1 of 3)
• List the body’s physiological changes
during acclimatization.
• Predict and prevent acute mountain
sickness (AMS).
Lesson Objectives (2 of 3)
• Assess and manage AMS, including high
altitude pulmonary edema and high
altitude cerebral edema.
• Assess and manage cold weather injuries,
including hypothermia, frostbite, immersion
(trench) foot, and chilblains.
Lesson Objectives (3 of 3)
• Assess and manage heat illnesses,
including heat exhaustion, heatstroke, and
heat cramps.
• List lightning safety guidelines and know
how to assess and manage injuries
caused by lightning.
Overview
• Altitude, extreme temperatures, wind, rain, and
lightning cause injuries and illnesses that do not
commonly occur in urban areas.
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Acclimatization (1 of 2)
• The physiological changes in the body
that compensate for hypoxia at altitudes
above 8,000 feet.
• Best achieved through slow, progressive
ascent.
• Rate and depth of breathing increase to
improve oxygen delivery to the blood.
Acclimatization (2 of 2)
• Heart beats more quickly and strongly.
• Bone marrow produces more red cells.
• Number of capillaries increase.
Acute Mountain Sickness (1 of 10)
• Travel above 8,000 feet results in lower
levels of oxygen in the blood.
• AMS strikes those who ascend too high too
fast and those who have not acclimatized to
high altitudes.
Acute Mountain Sickness (2 of 10)
• Predicting AMS
– Cannot predict who will suffer.
– Those who have suffered AMS before are
more likely to experience it.
– Fitness and training offer no guaranteed
protection.
Acute Mountain Sickness (3 of 10)
• Prevention of AMS
– Allow ample time to acclimatize at various
levels of ascent.
• High altitude climbing
– Mild AMS can develop at 6,000 feet.
– Above 13,000 feet, climbers should reach
sleeping altitude about 1,000 feet higher
than the previous day.
Acute Mountain Sickness (4 of 10)
• High altitude climbing (continued)
– Climbers who become sick and do not improve
must descend 1,000 to 3,000 feet.
– Drink 4 to 5 quarts of fluid daily.
– Avoid alcohol, sedatives, and sleeping pills.
Acute Mountain Sickness (5 of 10)
• Mild AMS
– What to look for:
• Headache that often develops at night
• Unusual fatigue
• Appetite loss and nausea
• Restless sleep with irregular breathing
• Shortness of breath with exertion
• Swollen face with bags under the eyes
Acute Mountain Sickness (6 of 10)
• Mild AMS
– What to do:
• Rest and do not go any higher.
• Administer aspirin or acetaminophen.
• If symptoms increase, descend.
• Administer acetazolamide.
• Give dexamethasone for severe headache.
• Be alert for progression to severe altitude
sickness.
Acute Mountain Sickness (7 of 10)
• High altitude pulmonary edema (HAPE)
– What to look for:
• Shortness of breath
• Cough producing frothy, blood-stained sputum
• Rattling or crackling and moist breathing
• Cyanosis
• Rapid pulse
Acute Mountain Sickness (8 of 10)
• High altitude pulmonary edema (HAPE)
– What to do:
• Descend.
• Give oxygen.
• Commence treatment in portable
compression chamber.
• Administer acetazolamide and/or nifedipine.
Acute Mountain Sickness (9 of 10)
• High altitude cerebral edema (HACE)
– What to look for:
• Severe, constant throbbing headache
• Incoordination
• Extreme fatigue not relieved by rest
• Hallucinations
• Vomiting
• Coma
Acute Mountain Sickness (10 of 10)
• High altitude cerebral edema (HACE)
– What to do:
• Descend.
• Treat for several hours in a portable
hyperbaric bag.
• Prop victim up to improve breathing.
• Give 4 to 5 liters of fluid daily.
• Administer acetazolamide and
dexamethasone.
Cold Injury (1 of 20)
• Cold injuries include hypothermia, frostbite,
cold immersion injury, and chilblains.
• Hypothermia is a general cooling of the body
core that develops when the body’s
temperature drops more than 2ºF.
• Frostbite is freezing of skin and flesh.
Cold Injury (2 of 20)
• Hypothermia
– Exacerbated by inadequate clothing and
exhaustion
– Anxiety, injury, drugs, alcohol, and poor
nutrition predispose people to hypothermia.
– Wetness and wind chill can cause
hypothermia in all seasons.
Cold Injury (3 of 20)
• Hypothermia
– Means of heat loss
• Convection
• Conduction
• Evaporation
• Radiation
Cold Injury (4 of 20)
• Hypothermia
– Sources of heat gain
• Radiation
• Exercise
• Shivering
• Food
• Blood vessel constriction
• Insulation
Cold Injury (5 of 20)
• Mild hypothermia
– What to look for:
• Shivering
• Uncharacteristic behavior
• Stiff muscles and cramps
• Cold, pale, and blue-gray skin
Cold Injury (6 of 20)
• Mild hypothermia
– What to do:
• Find shelter.
• Light a fire or stove.
• Change or remove wet clothes and
add dry layers.
• Give food and hot drinks.
• Allow shivering to continue inside a
sleeping bag.
Cold Injury (7 of 20)
• Mild hypothermia
– What to do:
• Give warm, sweet liquids.
• Provide rest and warmth.
• Never leave a hypothermic victim alone!
Cold Injury (8 of 20)
• Severe hypothermia
– What to look for:
• No shivering
• Behavior changing from erratic to apathetic
to unresponsive
• Stiff muscles and uncoordinated movement
• Weak, slow, irregular pulse
• Slow breathing
• Coma, with dilated pupils
Cold Injury (9 of 20)
• Severe hypothermia
– What to do in the field:
• Concentrate effort on reducing further heat loss.
• Do not endanger other members of the party.
• Shelter the victim.
• Stop further heat loss.
• Provide heat to the victim’s trunk.
• Cover the victim’s head.
Cold Injury (10 of 20)
• Severe hypothermia
– What to do (rescue):
• Leave at least one person with the victim.
• Send for help.
• Do not change your plan, even if victim
improves.
• If you must carry the victim out, insulate
him or her well.
• Choose the safest route.
Cold Injury (11 of 20)
• Severe hypothermia
– What to do (base camp):
• If rescue is impossible or days away, use all
available means to rewarm the victim slowly.
• Do not try rapid rewarming.
• Give plenty of warm, sweet liquids.
• Do not place warm objects directly on the
victim’s skin.
Cold Injury (12 of 20)
• Deep hypothermia
– Body core temperature falls below 82ºF.
– Pupils can be dilated and fixed, the limbs stiff,
and the skin icy.
– Should attempt resuscitation if there is even a
remote chance at recovery.
– Only sure sign of death is failure to revive with
rewarming.
Cold Injury (13 of 20)
• Immersion hypothermia
– Has rapid onset and a faster rate of cooling
– Heat loss is 25 times faster in water than in air.
– Can develop in less than an hour in water
colder than 45ºF.
– Begin CPR as soon as possible.
Cold Injury (14 of 20)
• Frostbite
– Localized freezing of tissues.
– Contributing factors include: wetness, contact
with metal, prolonged exposure, dehydration,
poor nutrition, extremely cold temperatures,
and immobilization.
Cold Injury (15 of 20)
• Frostbite
– Types of frostbite
• Frostnip: Superficial injury involving the
surface of the skin
• Superficial frostbite: Involves all layers of
skin but not underlying fat, muscles, or
other tissue
• Deep frostbite: Involves the skin and
underlying tissues
Cold Injury (16 of 20)
• Frostbite
– What to look for:
• White, waxy skin that has no feeling and is
wooden to the touch
• Possible thawing (skin is soft and body part
can appear gray or purple; skin tingles
painfully; blisters develop within a few hours.
Cold Injury (17 of 20)
• Frostbite: What to do
–
–
–
–
Avoid a freeze-thaw-refreeze cycle.
Allow to thaw if more than 8 hours from help.
Keep clean and cover with dry dressing.
Elevate limb above the level of the heart.
Cold Injury (18 of 20)
• Frostbite: What to do (continued)
– If thawing is inevitable and/or if transportation is
assured, warm in water 104–108ºF for 30 to 40
minutes.
– Dry carefully.
– Protect from further damage.
– Evacuate.
Cold Injury (19 of 20)
• Immersion (trench) foot
– A nonfreezing cold injury caused by prolonged
exposure to cold but without freezing.
– Prevent by keeping feet warm and dry.
– Treat by elevating the feet and exposing to air.
– In severe cases, evacuate.
Cold Injury (20 of 20)
• Chilblains
– Caused by repeated exposure of bare
skin to wet, wind, and cold.
– Causes red, itchy, tender, swollen skin.
– Prevent by wearing gloves.
Heat Illness (1 of 7)
• The body balances heat loss against heat gain.
• Evaporation of sweat dissipates heat, but fluid
and salt are also lost.
• Factors that can predispose one to heat illness:
– Dehydration
– Factors that limit the ability to sweat
– Prior cardiovascular problems
Heat Illness (2 of 7)
• Heat exhaustion: What to look for
– Inability to continue exercise or work due to
symptoms
– Headache, dizziness, fatigue, nausea, and vomiting
– Rapid pulse
– Thirst and profuse sweating
– Gooseflesh, chills, and pale skin
– Low blood pressure with possible fainting
Heat Illness (3 of 7)
• Heat exhaustion
– What to do:
• Rest and maximize air circulation.
• Remove excess clothing.
• Wet the victim with cold water.
• Have victim drink fluids.
Heat Illness (4 of 7)
• Heat exhaustion
– What to do (continued):
• In severe cases, add 0.25 tsp of salt and
6 tsp of sugar to 1 liter of water.
• If body temperature is greater than 102ºF,
seek medical care.
Heat Illness (5 of 7)
• Heatstroke: What to look for
– Headache
– Drowsiness, irritability, unsteadiness,
confusion, delirium, convulsions, coma
– Rapid pulse
– Low blood pressure
– Dry or sweat-moistened hot skin
– Body temperature greater than 106ºF
Heat Illness (6 of 7)
• Heatstroke: What to do
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–
–
–
Remove victim from heat.
Remove clothing.
Start immediate, rapid cooling.
Stop cooling when body temperature falls to
102ºF or when mental status improves.
– Monitor temperature frequently.
Heat Illness (7 of 7)
• Heat cramps
– What to look for:
• Cramps in the calf, thighs, or abdomen
following exercise
– What to do:
• Stretch affected muscles.
• Give salted fluids.
• Do not give salt tablets.
Lightning Injury (1 of 4)
• Kills by stopping the heart and breathing.
• External injury and superficial and deep
burns can occur.
Lightning Injury (2 of 4)
• Lightning safety guidelines
– Avoid:
• Isolated tall trees, hilltops, power lines or
pylons, small exposed shelters
• Tents
• Hill ridges and summits
• Rock walls
Lightning Injury (3 of 4)
• What to look for:
– Loss of consciousness
– Superficial steam burns
– Shredded clothing or shoes that have
been blown off
– Blue, mottled limbs
– Fractures or internal injuries
Lightning Injury (4 of 4)
• What to do:
–
–
–
–
Check breathing.
CPR if necessary.
Check for injuries.
Give supportive care: Maintain airway,
provide shelter, monitor vital signs.
– Evacuate.