bls 2014: environmental emergencies. this course addresses: cold and heat related emergencies ...
TRANSCRIPT
© 2013 Seattle / King County EMS
BLS 2014: Environmental Emergencies
© 2013 Seattle / King County EMS
This course addresses: Cold and heat related emergencies Water emergencies Stings & bites Anaphylaxis and use of the epi-pen Toxic gases Electric shock and lightning strike
Introduction
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Objectives Identify the ways the body produces and loses heat. Identify signs, symptoms, and emergency care of heat-
related emergencies. Identify signs, symptoms, and emergency care of cold-
related emergencies. Identify signs, symptoms, and emergency care of
water-related emergencies Identify signs, symptoms, and emergency care of bites
and stings Identify signs, symptoms, and emergency care of
anaphylaxis and severe allergic reaction Identify signs, symptoms, and emergency care of bites
and stings Identify signs, symptoms, and emergency care of toxic
gas exposure Identify signs, symptoms, and emergency care of
electric shock and lightning strike
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Heat Production and Loss
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Heat Production
Three ways body can produce heat: Metabolism Shivering Exercise
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Metabolism Metabolism
Conversion of food to energy Activity of bodily functions (such as
circulation, respiration and muscle tone)
Some substances broken down to create energy while other substances are synthesized into tissue building material
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Shivering
Rapid contraction & expansion of muscle tissues
Shivering can produce 40 times more heat than baseline metabolism
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Exercise Produce heat through exercise Happens as long as there is
activity, fuel (for instance, glucose or fat), oxygen and water
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Factors That Affect Heat Production Many factors affect how well body
can produce heat: Core temperature Medical conditions Body fluid status (dehydration) Drugs and chemicals
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Factors That Affect Heat Production Core Temperature Colder body – less
able it to produce adequate heat through metabolism
Hypothermia greatly reduces body’s ability to produce heat Cooling slows
chemistry of body
Medical Conditions Cardiac disease
decreases ability to compensate for heat stress
Endocrine diseases such as thyroid, adrenal & insulin deficiencies may contribute to hypothermia
Strokes can cause immobility with reduced muscular activity Temperature control centers of brain may be damaged
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Factors That Affect Heat Production Body Fluid Status Metabolism is not as
efficient when the body is dehydrated
Dehydration is a common problem in hot environments.
Drugs and Chemicals Beta-blockers
decrease cardiac output & peripheral vascular control mechanisms Effect works to lower
body temperature Drugs such as cocaine
and amphetamines may contribute to hyperthermia (heatstroke) Mimic stimulation of
sympathetic nervous system
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Heat Loss
Four heat loss mechanisms are: Conduction Convection Radiation Evaporation
Under normal conditions, heat loss mechanisms are balanced with heat
production mechanisms
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Conduction Transfer process – heat moves between two
touching objects (From warmer object to colder object)
Motion of molecules bumping into one another spreads heat
Molecules bump around like billiard balls on a billiards table
Major source of heat loss in case of cold-water immersion Water conducts heat 25 times more quickly than air
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Convection As air warms, rises &
cooler air replaces it Cool air then is warmed Example – blow on your
food to cool it Transfer of heat
between body & air or water that surrounds it
Occurs when a gas or liquid carries heat away
Body’s heat energy is lost more rapidly in moving air or water
Example – rising warm air from earth’s surface
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Radiation Warm body releases
energy without direct contact
Heat energy travels by bumping molecules (as in conduction) Also travel through
electromagnetic waves Sun is best known
example of heat transfer through radiation
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Evaporation Conversion of a liquid to
a gas Heat pan of water,
energy applied to water will cause to evaporate Requires a lot of heat Takes a lot of energy to
break water molecules apart & convert liquid to gas
Human body takes advantage of evaporation’s heat loss powers by sweating
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Heat Illness
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Heat Cramps
Heat cramps or muscle cramps result from uneven distribution of body fluids & salts
Muscle cramps from this condition can be mild to severe, involving the extremities or the abdomen
Cramps can be accompanied by: Dizziness Weakness Nausea
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Heat Exhaustion Named for feeling of
exhaustion people experience
Result of excessive heat & dehydration Reduce circulating
blood volume & increase peripheral pooling due to vasodilation
Cooling mechanisms of radiation & evaporation become inefficient due to loss of fluids :
Clinical findings associated with heat exhaustion include: Dizziness, weakness
and nausea Rapid, weak pulse Cool, clammy skin Profuse sweating Altered LOC
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Heatstroke Life-threatening
emergency – occurs when body's heat-regulating ability fails
Happens when body is subjected to more heat than it can deal with & four heat loss mechanisms overwhelmed
Clinical findings of heatstroke include: Altered LOC
(confusion, disorientation, or unconsciousness)
Rapid, bounding pulse
Rapid, deep respirations
Hot, dry, flushed skin*
Dilated pupils Seizures
* Can be damp if rapid onset
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Emergency Care for Heat-Related Emergencies Reduce core temperature:
Remove or loosen clothing Provide a cool environment Apply cool packs
Request paramedics when ALS indicators are present
provide oxygen and/or ventilatory assistance
Position patient appropriately Monitor vital signs Patient responsive & not nauseated,
consider giving water
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Cooling Strategies
Provide a Cool Environment As soon as time allows, move patient
to back of air-conditioned aid car with the air conditioner running on maximum
Fan patient aggressively if staffing allows
Keep skin wet by applying cool water with a sponge or wet towel
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Cooling Strategies
Remove Clothing Loosen or remove clothing to promote
efficient convention Consider applying water with a
sponge or wet towels on patient’s skin
If you apply water to skin to encourage evaporation, use room temperature water Do not induce shivering
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Cooling Strategies
Apply Cold Packs Neck, groin & armpits Hospitals generally have tools
necessary to properly lower core temperature Do not delay transport Notify hospital early to allow ED
staff time to prepare
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Cold Exposure
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Hypothermia Cooling of core
temperature below 98.6°F
Caused by loss of body heat or decreased heat production
Exposure to a cool environment Immobile elderly person
lying on a floor Drowning victim & who
has been submerged
Hypothermia can occur rapidly in wet environments
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Hypothermia
Early recognition increases chances of survival
HypothermiaStage Signs & Symptoms
Mild Hypothermia90-95°F
Alert, signs of fatigue & weakness Poor circulation Muscle stiffness
Moderate Hypothermia80-90°F
Confusion, lethargy Weak pulse, dysrhythmias Slow respirations
Severe Hypothermia
less than 80°F Coma Fixed and dilated pupils Cardiac arrest
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Frostbite Superficial Injury - Clinical Findings Blanching of skin Loss of feeling &
sensation in injured area Tingling sensation if re-
warmed
Deep Injury - Clinical Findings White, waxy skin Swelling and/or blisters Skin can appear flushed
with areas of purple & blanching or mottled & cyanotic
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Emergency Care for Cold-Related Emergencies Pre-hospital emergency care for a
hypothermic patient is as follows: Remove patient from cold
environment Protect from heat loss Provide high-flow oxygen
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Emergency Care for Hypothermia
Remove from Cold/Protect from Heat Loss Move patient to aid car warmed to
80°F Keep patient flat Remove wet clothing May need to protect from heat loss by
insulating patient with blankets
Provide High Flow Oxygen Provide high flow oxygen via BVM for
a non-breathing patient
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Hypothermic Cardiac Arrest Hypothermic patient in cardiac arrest or
with profound bradycardia, following guidelines apply: If no pulse detected after 1 minute, begin
CPR & apply AED If breathing, assume there is cerebral
perfusion, therefore NO CPR If AED analysis yields a “shock indicated”
follow cardiac arrest protocol If pulse is present withhold CPR regardless
of rate or BP
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Emergency Care for Frostbite
Protect affected area from further injury
Remove constricting or wet clothing & jewelry
Cover with dry bulky dressing Splint affected extremity, prevent
use of extremity
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Transport Times Over Two Hours Do not re-warm frozen tissue unless
transport time will exceed 2 hours & you are certain the thawed tissue will not refreeze
Obtain medical direction prior to initiating re-warming
Re-warming should be done with 100 – 105°F water
Do not use dry heat—it heats unevenly and can burn frozen tissue
Stop re-warming when tissue turns red-purple & becomes pliable
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Water Related
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Drowning and Near Drowning Several things
you should determine: Length of
submersion Temperature of
water Depth of water
Drowning – death caused by hypoxia following submersion in water
Near drowning – submersion in water that does not result in death
Without oxygen, hypotension, bradycardia & cardiac arrest ensue
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Length of Submersion Include length of submersion in report to
hospital staff May have to estimate based on bystander testimony & other indicators
Submersion is short duration (2 minutes or less), a short period of CPR likely will result in successful resuscitation
Significant number of near-drowning patients who look fine initially develop pulmonary edema several hours later
Non-cardiac related condition is called acute respiratory distress syndrome (ARDS).
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Water Temperature Submersion times greater than 10
minutes make successful resuscitation unlikely
High survival rates for cold water drowning's are a myth – there are rare cases of successful resuscitations after long submersions, but most long submersions do not survive, or survive with devastating neurologic outcomes.
Contrary to popular belief, children do not have better neurologic outcomes than adults
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Depth of Water Spinal injuries seen in many water-
related accidents Diving into shallow water common
mechanism for head & spinal injury & subsequent drowning Potential for a spinal injury, stabilize
cervical spine while in the water, if possible Other conditions associated with
drowning: Skeletal & soft tissue injuries Drug or alcohol intoxication Underlying medical conditions
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Emergency Care for Drowning/Near Drowning Management requires prompt basic
life support & following measures: Safely remove victim from the water Stabilize c-spine and place patient on a
backboard* Follow resuscitation protocols for cardiac or
pulmonary arrest Administer oxygen and/or ventilatory
assistance Place in a supine position to avoid cerebral
edema Prepare suction and expect vomiting Warm up the aid unit Monitor vital signs
*If spine injury is suspected or patient is unresponsive. If possible, initiate
stabilization during removal from water.
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Diving Emergencies Use of compressed air in an
underwater environment can be hazardous
In addition to drowning, common diving-related hazards include air embolism and decompression illness
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Air Embolism
Air embolism – presence of gas bubbles in bloodstream that obstruct circulation Occurs during ascent when pressure
in lungs forces air
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Air EmbolismSigns: Apnea (no
breathing) Frothy fluid from
nose or mouth Loss of
consciousness Partial weakness or
paralysis Seizures Irregular pulse Death
Symptoms: Dizziness Confusion Chest pain Diminished sensation
in parts of the body Visual blurring
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Decompression Sickness Nitrogen in blood
forms bubbles due to rapid ascent
Bubbles collect in tissues & interfere with blood flow
Significant history for all diving emergencies includes: Number of dives in
past 24 hours Depth of dive Length of time
underwater Problems encountered
while diving Significant medical
history (including meds)
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Decompression Sickness Dive usually at
depth of at least 33 feet Less likely at depths
<33 feet Still can happen
Longer & deeper the dive, more nitrogen dissolves in blood
Dehydration, exertion & air travel within 12 hours after diving all increase the probability of DCI
Symptoms of DCI vary widely depending on where bubbles collect Joint pain, abdominal
pain, neurological symptoms & difficulty urinating are common
Diver who complains of feeling ill after diving should be evaluated for DCI
Symptoms can appear within a few minutes of surfacing or it may take hours
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Treatment for Diving InjuriesDefinitive treatment for any significant diving emergency is recompression in a hyperbaric facility!
Emergency care ABCs High flow 100% oxygen Place the patient in a position of comfort (“head down, feet
up” is no longer recommended) Request ALS intervention as needed
Gather information on: Maximum depth dived Time on the bottom Time since reaching surface Whether the dive was single or multiple dives were done.
If the patient is to be flown by helicopter then advise the crew that this is a decompression accident. This prepares the crew for low fly or cabin pressure alterations during flight.
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Bites and Stings
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Bites and stings
Animals of all types from dogs to bees may bite or sting to defend themselves or their young. Bites and stings can cause problems ranging from local tissue damage to systemic symptoms.
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Mammal Bites and Scratches Local tissue damage Bleeding (can be significant depending on the
size of the animal and patient, and location of the wound)
Puncture wounds increase the risk of infection Remote risk of rabies (viral disease transmitted
by saliva of infected mammals)
Emergency care ABCs Control bleeding, sterile dressing Identify the animal (contain if possible) Evaluation at ER or clinic for possible antibiotics
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Snake Bites Snakes bite if threatened or to obtain food
(typically small mammals) Only a small percentage of snakes in the US
are poisonous Even poisonous snakes often bite without
envenomation Sometimes people keep poisonous snakes as
pets Alcohol use is a significant factor in many
snakebites Signs and symptoms range from local tissue
damage to systemic effects, and vary depending on the type of snake
Zoos are excellent sources of information about snakebites and often stock antivenom
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Snake Bites
Emergency care Non-poisonous snake: wound care Poisonous snake:
ABCs Request ALS if indicated Constricting bands, suction of bite are no
longer recommended Remove jewelry from affected limb before
swelling begins, if possible Bandage and immobilize site of injury
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Invertebrate Stings and Bites
Include bees and wasp stings, spider bites, and stings of marine animals such as urchins
Reactions can include tissue irritation, local allergic reaction, anaphylaxis, or systemic symptoms
If possible, identify the type of animal responsible for the bite/sting
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Stings and Bites
Insects & spiders inject a poison when they bite or sting
Two types of spiders deliver life-threatening bites: brown recluse & female black widow
Brown recluse Black widow
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Stings and Bites
Many marine animals, such as sharks or urchins, have spines that contain proteins that can cause a local reaction and, occasionally, an anaphylactic reaction
Some tropical species (e.g., the Lionfish) found in aquariums can cause envenomation.
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Emergency Care for Invertebrate Bites and Stings
Request ALS if indicated Scrape the sting site to remove the
stinger Wash the area Remove jewelry from affected limb
before swelling begins, if possible Bandage and immobilize site of
injury If there are signs and symptoms of
anaphylaxis or severe allergic reaction, administer epinephrine via EpiPen if indicated
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Anaphylaxis/Severe Allergic Reaction
Exaggerated response of the body to a foreign protein (for example, the venom in a bee sting or peanuts)
Caused by an overproduction of histamine
Too much histamine causes: Vasodilitation, resulting in hypotension Bronchoconstriction, resulting in dyspnea GI distress, including diarrhea and
abdominal pain There may also be local or generalized
swelling and widespread urticaria (hives)
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Emergency Care for Anaphylaxis ABCs Request ALS Oxygen Trendelenberg if patient is
hypotensive Administer epinephrine via EpiPen
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Epi-pen AdministrationInjection Procedure for the Epi-Pen or epi-pen jr:1. Check medication date and that the EpiPen dose matches
with the patient’s size.2. Remove the patient’s clothing and prep the thigh with an
alcohol pad.3. Remove safety cap and locate injection site on lateral
thigh.4. Place the black tip of the injector against the patient’s
thigh and push hard until it activates.5. Hold it in place for 10 seconds, and document the time of
injection.6. Remove the injector and place it in a sharps container.
Massage the injection site for 10 seconds.7. Reassure the patient and monitor for response and side
effects to the injection.8. Continue to provide oxygen. Ventilate the patient if
necessary.9. Monitor and document patient vitals every 5 minutes.10. Update incoming medics on patient status and response to
the injection.
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Toxic Gases
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Toxic Gas Poisoning Scene safety is of paramount importance Determine type of exposure and length of time
exposed Consider toxic gas if multiple people are
affected Carbon monoxide is the most common toxic
gas unvented burning of fuel in the winter (particularly
during power outages as people try to stay warm) smoke inhalation from house fires suicide
Be aware of possible toxic gas in tunnels, silos, and other unvented locations
If large numbers of people are affected and circumstances are suspicious, be alert to the possibility of terrorism
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Toxic GasesCarbon monoxide (CO) Odorless, colorless gas Found in products of combustion, such as those
produced by cars and trucks, small engines, stoves, burning charcoal, wood, gas ranges and heating systems.
Can build up in enclosed spaces Can also occur in structure fires Binds to the hemoglobin of red blood cells, impairing
oxygen carrying capacity Half-life of CO in the blood:
Room air: 240-360 minutes O2 (100%): 80 minutes Hyperbaric (high pressure) O2: 22 minutes
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Toxic GasesCyanide (CN) Toxic compound often in the form of a gas
(hydrogen cyanide) Can be formed in the burning of plastics and
other materials (for example in house fires) Rare cases of industrial exposure, suicide, or
poisoning Cellular poison
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Nerve AgentsNerve agents (organophosphates) Used in agriculture as insecticides (examples
include parathion, diazinon) Can be absorbed through skin or lungs, or
ingested Since WWII, have been used for chemical
warfare More recently have been used by terrorists
(sarin release in Tokyo subway) Occasional cases of suicide by ingesting
organophosphate pesticides Alters the transmission of nerve impulses by
affecting neurotransmitters throughout the body
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Other Toxic Gases
Other toxic gases Methane, nitrogen dioxide may be
formed in sewers, silos, and other enclosed spaces
Chlorine, phosgene, and others may be released by industrial accidents
Presentation varies depending on type of gas; scene safety and ABCs are always indicated
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Emergency care Ensure scene safety, remove the patient from the
exposed area ABCs, vitals Request ALS if indicated High flow oxygen Depending on the scenario, be prepared for multiple
patients (notify other responders, hospitals as soon as possible) Possible CN:
ALS may be able to administer a cyanide antidote
Possible nerve agent: Be prepared with suction
for massive secretions, vomiting, etc.
ALS may be able to administer a nerve agent antidote
Possible CO: If a CO monitoring is
available, obtain a reading from the structure or source, and the patient
Pulse oximeter readings are not reliable in CO poisoning!
Consider transport destination (the patient may benefit from hyperbaric oxygen)
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Electrical Emergencies
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Electric Shock Smaller doses of current (70–700 mA)
trigger ventricular fibrillation. Larger doses of current ( >1amp) cause
burns, tissue, cell damage. Type of current (DC vs. AC), current
pathway, and duration of current also influence the severity of injury: AC current generally causes more damage due to
tetanic stimulation and prolonged duration of exposure.
DC current is typically shorter duration, creating a single muscle spasm causing the victim to be thrown from the source.
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Emergency Care Scene safety Do not touch any downed or active power lines, or
anything the power lines may be in contact with. Wear appropriate PPE Be aware of marked danger zones Remove the patient to a place of safety, once given the
OK by qualified personnel. ABCs Provide full spinal stabilization Look for two burn sites: an entrance and exit site, these
may be in unpredictable locations, for example in one hand, out the other; in one hand, out the bottom of the foot, etc.
External wounds do NOT reflect the extent of injury Electricity can travel through blood vessels, muscle,
bone, doing damage as it goes
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Lightning Responsible for approximately 50 deaths per
year in the US Estimates of several thousand injuries per year Lightning safety
Seek shelter indoors or in a car If trapped outdoors, avoid open fields, water, or
metal objects If indoors, stay off corded phones, don’t touch
metal/plumbing Cardiac arrest may occur; survival rates are
high if resuscitation is started promptly Major burns are uncommon Patients may suffer long-term neurologic
affects
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Emergency Care Evacuate to a safe indoor location if
lightning is still in the area (30 min since last lightning strike is standard)
If trauma (fall, thrown a distance, etc.), provide spinal immobilization
ABCs and vitals Request ALS Defib protocols if patient is in cardiac arrest Cover burns, if any, with sterile dressing
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Electrocution
Don’t go near downed power line
Entrance Wound - Dark spot in center of wound
Exit Wound – where body closest to ground
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Summary: Heat and Cold Exposure
Heat cramps, heat exhaustion, & heatstroke are progressive phases of heat illness managed in the field by addressing dehydration and reducing core temperature
Four mechanisms cause heat loss: conduction, convection, radiation, & evaporation
Steps for prehospital emergency care for a hypothermic patient include: remove patient from cold environment, protect patient from heat loss, and provide oxygen
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Summary: Water-Related Emergencies For drowning patients, safely remove
from water, stabilize c-spine if indicated, and follow general resuscitation guidelines Extended submersion time has a poor
overall outcome For diving emergencies, gather
significant history including depth of dive and length of time underwater Treat with high flow oxygen and ALS as
indicated Definitive treatment for any significant
diving emergency is recompression in a hyperbaric chamber
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Summary: Bites and Stings Control bleeding, identify animal,
evaluate at ER of clinic For bee stings, remove stinger, request
ALS if indicated, consider epi-pen Hypotension, respiratory distress,
widespread hives Epi-pen administration request an ALS
eval
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Summary: Toxic Gases
Scene safety! Determine type of exposure Carbon monoxide is the most
common (unvented burning of fuel, smoke inhalation from fires, etc.)
Also consider cyanide, organophosphates, others
Treatment: scene safety, high flow oxygen, ALS as indicated
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Summary: Electrical Injuries
Electric shock can cause burns, tissue damage, and cardiac arrhythmias (particularly VF)
Lightning strike may also cause cardiac arrest
External wounds (burns) do not represent the extent of the internal damage
Treat with normal defib protocols after ensuring that the scene is safe