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ENVIRONMENTAL EMERGENCIES. Environmental Objectives. Upon completion the student will be able to: Describe the four ways in which the body loses heat Describe mechanisms used by the body to maintain a core temperature in both warm and cold environments

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environmental emergencies

ENVIRONMENTAL EMERGENCIES

Intermediate Lecture – Environmental Emergencies

environmental objectives
EnvironmentalObjectives

Upon completion the student will be able to:

  • Describe the four ways in which the body loses heat
  • Describe mechanisms used by the body to maintain a core temperature in both warm and cold environments
  • Distinguish between hyperthermia and hypothermia
  • Identify the signs, symptoms, and recommended management techniques for heat cramps, heat exhaustion, water intoxication and heat stroke
  • Discuss the pathology of hypothermia and cold-related injuries

Intermediate Lecture – Environmental Emergencies

objectives
Objectives
  • Identify the stages of systemic hypothermia, and describe the physical signs and symptoms associated with them
  • Identify non-environmental causes of hypothermia
  • Discuss the concerns and precautions involved in rewarming a hypothermia patient in the field
  • Describe the events that occur during the near-drowning emergency
  • Identify the sources of ionizing radiation, and relate their relative penetrating potential
  • Name some of the factors that can help reduce exposure to a radiation source

Intermediate Lecture – Environmental Emergencies

environmental objectives1
EnvironmentalObjectives
  • Identify prehospital management of a patient who has been exposed to ionizing radiation
  • Identify common diving/hyperbaric emergencies
  • Describe the signs and symptoms of diving-related emergencies
  • Describe the management of the patient with a diving-related emergency

Intermediate Lecture – Environmental Emergencies

introduction
INTRODUCTION
  • Environment: all of the surrounding external factors that affect the development and functioning of a living organism.
  • External environment is a necessity of life but we must also be protected from it.
  • Most emergencies occur during the summer or winter.

Intermediate Lecture – Environmental Emergencies

thermoregulation
THERMOREGULATION
  • Body functions within a very small temperature range.
  • Core temperature does not vary more than a degree or so from its normal 98.6 degrees F (37 degrees C).
  • This is known as the steady-state metabolism. This characteristic is normal in all warm-blooded animals.

Intermediate Lecture – Environmental Emergencies

generation loss of heat
Generation & Loss of Heat
  • Amount of heat in the body continually fluctuates between the heat generated and the heat lost.

Intermediate Lecture – Environmental Emergencies

heat generation internal heat
Heat GenerationInternal Heat
  • Comes from routine cellular metabolism and a process called thermogenesis.
  • When the cell produces energy, it gives off heat.
  • Sympathetic stimulation will cause heat increases because of the increase in cellular metabolism.

Intermediate Lecture – Environmental Emergencies

heat generation internal heat1
Heat GenerationInternal Heat
  • The body can stimulate certain cells to generate heat through thermogenesis.
  • Primarily fatty tissue.
  • Shivering can further generate heat through skeletal muscle contraction.
  • Heat can also be generated through strenuous exercise, which increases metabolic rates.

Intermediate Lecture – Environmental Emergencies

heat generation environmental heat
Heat GenerationEnvironmental Heat
  • Body receives external heat from the environment via the thermal gradient.
  • Defined: difference in temperature between the environment and the body.
  • Environment is warmer than the body, heat flows from it to the body.
  • Body is warmer than the environment, heat flows from the body to the environment.

Intermediate Lecture – Environmental Emergencies

heat generation environmental heat1
Heat GenerationEnvironmental Heat
  • Factors that affect the thermal gradient:
    • Ambient air temperature ( temp. of the surround air)
    • Infrared radiation (radiation with a wavelength longer than that of visible light)
    • Relative humidity (% of water vapor present in air)

Intermediate Lecture – Environmental Emergencies

heat loss
Heat Loss
  • Heat generated by the body is constantly lost to the environment.
  • Occurs because the body is usually warmer than the surrounding environment.
  • Occurs through the following methods:

Intermediate Lecture – Environmental Emergencies

heat loss radiation
Heat LossRadiation
  • Unclothed person will lose approximately 60% of total body heat by radiation at normal room temperature.
  • Heat loss is in the form of infrared rays.
  • All objects not at absolute zero temperature will radiate heat.

Intermediate Lecture – Environmental Emergencies

heat loss conduction
Heat LossConduction
  • Direct contact of the body’s surface to another, cooler object causes the body to lose heat.
  • Heat flows from higher temperature matter to lower temperature matter.
  • Law of thermodynamics states that if ambient air temperature is higher than the skin temperature, then heat will flow from the air to the skin.

Intermediate Lecture – Environmental Emergencies

heat loss convection
Heat LossConvection
  • Heat loss to air currents passing over the body.
  • However, heat must first be conducted to the air before being carried by convection currents.

Intermediate Lecture – Environmental Emergencies

heat loss evaporation
Heat LossEvaporation
  • Occurs as water evaporates from the skin.
  • Great deal of heat loss occurs through evaporation of fluids in the lungs.
  • Water evaporates from the skin and lungs at approximately 600 ml/day.

Intermediate Lecture – Environmental Emergencies

heat controlling mechanisms
Heat-Controlling Mechanisms
  • Nervous or negative feedback mechanism regulate the body’s temperature almost entirely.
  • Most mechanism operate through temperature-regulating centers located in the hypothalamus.
  • Functions like a thermostat, produces neurosecretions important in the control of metabolic activities, including temperature regulation.

Intermediate Lecture – Environmental Emergencies

heat controlling mechanisms1
Heat-Controlling Mechanisms
  • There are temperature receptors in other parts of the body to help moderate temperatures.
  • They are located: in the skin, mucous membranes, selected deep tissues of the body.
  • Cold receptors outnumber warm receptors, peripheral detection of temperature consists mainly of detecting cold instead of warmth.

Intermediate Lecture – Environmental Emergencies

heat controlling mechanisms2
Heat-Controlling Mechanisms
  • Deep body temperature receptors lay mostly in the spinal cord, abdominal viscera, and around the great veins.
  • These receptors are exposed to the body’s core temperature rather than the surface temperature.
  • Respond mainly to cold rather than warmth.
  • Both skin and deep temperature receptors act to prevent hypothermia.

Intermediate Lecture – Environmental Emergencies

heat elimination
Heat Elimination
  • When the body becomes to hot, the hypothalamic thermostat attempts to eliminate body heat through 5 mechanisms. These include:
    • Vasodilation: blood vessels dilate due to the inhibition of the sympathetic centers in the hypothalamus. Heat is then lost through the skin by sweating and other mechanisms.

Intermediate Lecture – Environmental Emergencies

heat elimination1
Heat Elimination
  • Perspiration: occurs when the core temperature rises above “normal”. This mechanism is ineffective if the relative humidity is 75% or greater due to decreased evaporation of perspiration from the skin surface.
  • Decrease in Heat Production: shivering and chemical thermogenesis are inhibited, causing decreased heat production.

Intermediate Lecture – Environmental Emergencies

heat elimination2
Heat Elimination
  • Increased Cardiac Output: aids in increasing blood flow through the skin, thus aiding in the elimination of heat.
  • Increased Respiratory Rate: results in elimination of warm air and in water evaporation.

Intermediate Lecture – Environmental Emergencies

heat preservation
Heat Preservation
  • When body becomes too cold, the hypothalamic thermostat reacts in exactly the opposite fashion.
  • Body engages the following mechanisms:
    • Vasoconstriction: caused by stimulation of the hypothalamic sympathetic centers. Diverts the blood from the skin to the body’s core to maintain heat.

Intermediate Lecture – Environmental Emergencies

heat preservation1
Heat Preservation
  • Piloerection: (hairs standing on end). Increases the insulating ability of body hair and decreases heat loss.
  • Increased Heat Production: increased by the metabolic systems in the following ways:
    • Thermogenesis (shivering): hypothalamus has an area called the primary motor center that controls shivering. It is excited by cold signals from the skin and spinal cord.

Intermediate Lecture – Environmental Emergencies

heat preservation2
Heat Preservation
  • Sympathetic Stimulation: Norepinephrine and epinephrine are released following sympathetic stimulation, which causes an immediate increase in the rate of cellular metabolism and generates heat.

Intermediate Lecture – Environmental Emergencies

heat fluctuations
Heat Fluctuations
  • Summary:
    • Body temperature rises, cooling mechanisms are engaged. Hyperthermia
    • Body temperature drops, heat-preserving mechanisms are engaged. Hypothermia
  • Hyperthermia and fever are different. Fever occurs when the hypothalamus “resets” the “thermostat” in the brain. Part of the body’s defense mechanisms for infections.

Intermediate Lecture – Environmental Emergencies

thermal disorders
THERMAL DISORDERS
  • Discuss the following heat-related disorders:
    • Hyperthermia
    • Fevers
    • Hyperpyrexia
    • Hypothermia
    • Frostbite

Intermediate Lecture – Environmental Emergencies

hyperthermia
Hyperthermia
  • Increase in the body temperature caused by heat transfer from the external environment.
  • Manifests as:
    • Heat Cramps
    • Heat Exhaustion
    • Water Intoxication
    • Heat Stroke

Intermediate Lecture – Environmental Emergencies

heat muscle cramps
Heat (Muscle) Cramps
  • Common in hot climates.
  • Result in intermittent, painful contractions of various skeletal muscles.
  • Caused primarily by a rapid change in extracellular fluid osmolarity resulting from sodium and water losses.
  • Sweating occurs as sodium is transported to the skin.

Intermediate Lecture – Environmental Emergencies

heat cramps
Heat Cramps
  • Because “water follows sodium” it is deposited on the skin surface.
  • Evaporation occurs, thus aiding in the cooling process.
  • Sweating not only involves the loss of water, but also the loss of electrolytes.
  • Presents with cramps in the fingers, arms, legs, or abdominal muscles.
  • Generally alert, hot sweaty skin, tachycardia, normal BP and a normal core temperature.

Intermediate Lecture – Environmental Emergencies

heat cramps1
Heat Cramps

Prehospital Management

  • Remove from the environment.
  • Fluid and sodium intake increased.
  • May require IV fluid replacement with NSS

Intermediate Lecture – Environmental Emergencies

heat exhaustion
Heat Exhaustion
  • Most common heat related illness.
  • Dehydration and salt loss due to sweating account for the presenting symptoms.
  • Be aware that these symptoms may mimic those of patients suffering from fluid and sodium loss.
  • History of exposure to hot weather is needed to obtain an accurate assessment.

Intermediate Lecture – Environmental Emergencies

heat exhaustion signs symptoms
History of low-fluid intake

Decreased urine output

Positive orthostatic vital signs

Tachycardia

Nausea and vomiting

Dizziness and transient syncope

Headache

Muscle cramps

Diarrhea

Heat ExhaustionSigns & Symptoms

Intermediate Lecture – Environmental Emergencies

heat exhaustion1
Heat Exhaustion
  • Working in a hot environment will lose 1-2 liters of water an hour.
  • Each liter lost contains 20-50 mEq’s of sodium.
  • The loss of water and sodium, combined with general vasodilation, leads to a decreased circulating blood volume, venous pooling, and reduced cardiac output.

Intermediate Lecture – Environmental Emergencies

heat exhaustion2
Heat Exhaustion

Prehospital Management

  • Remove from hot environment
  • Provide IV fluid replacement (NSS)
  • If untreated, heat exhaustion can progress to heat stroke.

Intermediate Lecture – Environmental Emergencies

water intoxication
Water Intoxication
  • Occurs when an individual in a hot environment drinks water at a rate that exceeds fluid loss from sweating and fails to replace associated sodium losses.
  • Sodium levels drop causing S&S similar to those seen with heat exhaustion.
  • Common S&S include: N/V, headache, alterations in mental status.

Intermediate Lecture – Environmental Emergencies

water intoxication1
Water Intoxication
  • Patient usually reports water intake greater than 1 liter/hour and may exhibit urinary frequency and dilute urine.
  • Untreated may progress to alterations in mental status and coma.

Intermediate Lecture – Environmental Emergencies

water intoxication2
Water Intoxication

Prehospital Management

  • Encouraged to eat foods high in sodium.
  • Restrict further water intake.
  • Unresponsive patients, IV (KVO) NSS

Intermediate Lecture – Environmental Emergencies

heat stroke
Heat Stroke
  • Occurs when the body’s hypothalamic temperature regulation is lost, causing uncompensated hyperthermia.
  • Causing cell death and physiologic collapse.
  • Characterized by body temperature of at least 105 degrees F.
  • CNS disturbances, and usually the cessation of sweating.

Intermediate Lecture – Environmental Emergencies

heat stroke1
Heat Stroke
  • Sweating is thought to stop due to destruction of the sweat glands or when sensory overload causes them to temporarily dysfunction.
  • Patient’s skin may be either dry or covered with sweat.

Intermediate Lecture – Environmental Emergencies

heat stroke signs and symptoms
Increased core temperature

Tachycardia followed by bradycardia

Hypotension with low or absent diastolic reading

Rapid, shallow respirations, which may later slow

Confusion or disorientation

Seizures

Coma

Heat StrokeSigns and Symptoms

Intermediate Lecture – Environmental Emergencies

heat stroke2
Heat Stroke
  • If heat stroke is associated with exertion, the patient may develop severe metabolic acidosis caused by lactic acid accumulation.
  • Hyperkalemia may also develop because of the release of potassium from injured muscle cells, renal failure, or metabolic acidosis.

Intermediate Lecture – Environmental Emergencies

heat stroke prehospital management
Rapid Patient Cooling Body temp. must be lowered to 102 F

Administer oxygen method necessary. Pulse oximetry should be utilized.

Establish IV(s). Initially run wide open

Monitor ECG, dysrhythmias are common.

Avoid Vasopressors and Anticholinergic Drugs: potentiate heat stroke by inhibiting sweating.

Monitor core temp.

Heat StrokePrehospital Management

Intermediate Lecture – Environmental Emergencies

fever pyrexia
Fever (Pyrexia)
  • Elevation of the body temperature above the normal temperature for that person.
  • Body develops a fever when pathogens enter and cause infection, causing a stimulation of pyrogens.
  • Pyrogens are any substance that causes fever.
  • They reset the hypothalamic thermostat to a higher level.

Intermediate Lecture – Environmental Emergencies

fever
Fever
  • Metabolism is therefore increased, producing a fever.
  • Increased body temperature wards off infection by making the body a less hospitable environment for the invading organism.
  • Hypothalamic thermostat will reset to normal when pyrogen production stops or when pathogens end their attack on the body.

Intermediate Lecture – Environmental Emergencies

fever prehospital management
FeverPrehospital Management
  • Treat the underlying cause of the fever.
  • Usually no treatment is necessary unless it is very high (105 F) or changes in mental status exist or febrile seizures appear imminent.
  • Treatment consists of cooling (removal of clothes/convection) and possibly rectal Tylenol.

Intermediate Lecture – Environmental Emergencies

hyperpyrexia
Hyperpyrexia
  • Elevation of body temperature above 106 F.
  • Can be produced by physical agents such as hot baths or hot air or by reaction to infection caused by microorganisms.

Intermediate Lecture – Environmental Emergencies

hypothermia
Hypothermia
  • A state of low body temperature, specifically low body core temperature.
  • Less than 95 F is considered to be hypothermic state.
  • Attributed to either a decrease in heat production, an increase in heat loss, or a combination of both.

Intermediate Lecture – Environmental Emergencies

hypothermia1
Hypothermia
  • Exposure to cold normally causes shivering and increased muscle tone, resulting in increased metabolism to maintain the body temperature.
  • Initial signs are peripheral vasoconstriction with an increase in cardiac output and respiratory rate.
  • When these mechanisms fail the body temperature falls.

Intermediate Lecture – Environmental Emergencies

hypothermia2
Hypothermia
  • As body temperature falls, so does the metabolic rate and cardiac output.
  • Hypovolemia results from the shift of fluid from the vascular to the extravascular compartment, allowing the body to preserve energy and prevent cell death.
  • If not corrected, cell ischemia and necrosis eventually result in death.

Intermediate Lecture – Environmental Emergencies

hypothermia3
Hypothermia
  • Major sources of body heat loss are conduction, radiation, evaporation, and convection.
  • Heat loss can be increased by the removal of clothing, wetting of clothing, increased air movement around the body, or cold-water immersion.

Intermediate Lecture – Environmental Emergencies

hypothermia presentation
HypothermiaPresentation
  • Divided into three categories:
    • Mild
    • Moderate
    • Severe
  • Core temperature between 94 and 97 F is considered mild hypothermia
  • Core temperature between 86 and 94 F is considered moderate hypothermia
  • Core temperature less than 86 F is classified as severe hypothermia

Intermediate Lecture – Environmental Emergencies

hypothermia presentation1
HypothermiaPresentation
  • Mild to moderate hypothermia, patients will generally exhibit shivering.
  • May be lethargic and somewhat dulled mentally.
  • Muscles may be stiff and uncoordinated, causing the patient to walk with a stumbling, staggering gait.

Intermediate Lecture – Environmental Emergencies

hypothermia presentation2
HypothermiaPresentation
  • Severe hypothermia may be disoriented and confused.
  • Progress into stupor and complete coma
  • Shivering will usually stop, and physical activity becomes uncoordinated.
  • Muscles may be stiff and rigid
  • ECG will frequently show J waves, also called Osborn waves, associated with the QRS complexes.

Intermediate Lecture – Environmental Emergencies

hypothermia presentation severe
HypothermiaPresentation/Severe
  • Atrial fibrillation is the most common presenting dysrhythmia seen in hypothermia
  • As the body cools a wide variety of dysrhythmias may present
  • Bradycardia is inevitable
  • V Fib probable as temp drops below 86 F
  • Severe hypothermia patient requires assessment of pulse and respirations for at least 30 seconds every 1-2 minutes

Intermediate Lecture – Environmental Emergencies

metabolic factors in hypothermia
Metabolic Factors in Hypothermia
  • Not all hypothermia is environmental in cause.
  • Hypothyroidism depresses the body’s heat-producing mechanisms.
  • Brain tumors or head trauma can depress the hypothalamic temperature control center.
  • Other conditions: MI, diabetes, hypoglycemia, drugs, poor nutrition, sepsis, or old age.

Intermediate Lecture – Environmental Emergencies

metabolic factors in hypothermia1
Metabolic Factors in Hypothermia
  • Evaluate patient for level of consciousness, cool skin, and shivering.

Intermediate Lecture – Environmental Emergencies

prehospital management
Prehospital Management
  • Rewarming is best carried out by a team using a prearranged protocol in the hospital.
  • Most who die during rewarming die from V Fib.
  • Rewarming should not be attempted in the field unless travel to the ED will take more than 15 minutes.
  • External application of heat by warmed blankets is a safe and effective means of rewarming the hypothermic patient.

Intermediate Lecture – Environmental Emergencies

prehospital management1
Prehospital Management
  • Application of external heat results in peripheral vasodilatation.
  • This could cause the BP to fall.
  • IV should be in place.
  • Another means is the administration of heated and humidified oxygen.
  • Hypothermic patient should be moved gently.

Intermediate Lecture – Environmental Emergencies

prehospital management2
Prehospital Management
  • Unnecessary rough handling may stimulate the return of cool blood and acids from the extremities to the core.
  • Specific care steps should take place after an adequate initial survey of the hypothermic patient.

Intermediate Lecture – Environmental Emergencies

mild moderate hypothermia
Remove all wet clothes

Protect against heal loss and wind chill

Maintain horizontal position

Avoid rough movement and excess activity

Monitor the core temp

Monitor the ECG

Add heat to the patient’s head, neck, chest, and groin.

Respiratory warming may also be used

Do not give alcohol, coffee, or nicotine

Warm oral fluids and sugar sources

Mild/Moderate Hypothermia

Intermediate Lecture – Environmental Emergencies

severe hypothermia vital signs present
Remove all wet clothes

Protect against heat loss and wind chill

Maintain horizontal position

Avoid rough movement and excess activity

Monitor the core temp

Monitor the cardiac rhythm

Add heat to the patient’s head, neck, chest, and groin.

Respiratory warming also

Give nothing by mouth

Severe Hypothermia Vital Signs Present

Intermediate Lecture – Environmental Emergencies

severe hypothermia vital signs present1
Do not administer oxygen unless it is heated to >99F.

If warm O2 not available, use mouth-to-mask techniques

Establish and IV with warm fluids if possible

Do not administer medications:

Poorly metabolized

Due to poor perfusion the meds may persist in the body causing toxic levels upon patient rewarming

Severe HypothermiaVital Signs Present

Intermediate Lecture – Environmental Emergencies

severe hypothermia vital signs absent
Assess pulse and respirations for 1-2 minutes

If absent, begin CPR

Observe ECG, if V Fib deliver stacked shocks

Ventilate with warmed humidified oxygen

Initiate IV with warm fluids

Temp > 86F give IV resuscitation medications (slower rate)

Temp <86F withhold IV resuscitation medications, 3 shocks only

Rewarming should not be attempted in the field unless transport is >15 min

Severe HypothermiaVital Signs Absent

Intermediate Lecture – Environmental Emergencies

frostbite
Frostbite
  • Environmentally induced freezing of body tissues.
  • Ice crystals form within the tissues and water is drawn out of the cells into the extracellular space.
  • Ice crystals expand, causing the destruction of cells.
  • Damage to blood vessels from ice crystal formation causes loss of vascular integrity, resulting in tissue swelling and loss of distal nutritional flow.

Intermediate Lecture – Environmental Emergencies

frostbite1
Frostbite
  • Two types of frostbite:
    • Superficial frostbite: affects the dermis and shallow subcutaneous layers
    • Deep frostbite: affects the dermal and subdermal layers of tissue

Intermediate Lecture – Environmental Emergencies

frostbite assessment
FrostbiteAssessment
  • Occurs in extremities and in areas of the head and face exposed to the environment.
  • Subfreezing temperatures are required for frostbite to occur. This is not true with hypothermia.
  • Clinical sequence of events in the following order:
    • Extremities become cold -> then become painful -> pain gradually changes to numbness.
  • Skin may initially have the appearance of reddening.

Intermediate Lecture – Environmental Emergencies

frostbite assessment1
FrostbiteAssessment
  • Skin will change to a white or gray with full freezing.
  • In superficial frostbite there may be a degree of compliance beneath the frozen layer of the skin.
  • In deep frostbite the frozen part will be hard and non-compliant.

Intermediate Lecture – Environmental Emergencies

frostbite prehospital management
Do not thaw affected area if there is any possibility of refreezing

Do not massage the frozen area or rub with snow

Administer analgesia prior to thawing

Thaw frozen part by immersion rewarming in a 100-106 F water bath

Cover the thawed part with loosely applied, dry, sterile dressings

Elevate the thawed part

Do not puncture or drain the blisters

Do not allow the patient to ambulate on frozen feet

FrostbitePrehospital Management

Intermediate Lecture – Environmental Emergencies

near drowning and drowning

NEAR-DROWNING AND DROWNING

Intermediate Lecture – Environmental Emergencies

introduction1
INTRODUCTION
  • Approximately 8,000 persons die annually due to drowning in the U.S.
  • 40% of these are under the age of 5.
  • Second leading cause of accidental death in people ages 1-44.
  • 85% of near-drowning victims are male
  • Drowning: death occurred within 24 hours of submersion
  • Near-Drowning: death either did not occur or occurred more than 24 hours after submersion

Intermediate Lecture – Environmental Emergencies

pathophysiology
Pathophysiology
  • Following submersion, if the victim is conscious, there will be a period of complete apnea for up to 3 minutes.
  • Apnea is a involuntary reflex as the victim strives to keep the head above water.
  • The blood is shunted to the heart and brain (diving reflex).
  • When apneic the PaCO2 in the blood rises to greater than 50 mmHg.

Intermediate Lecture – Environmental Emergencies

pathophysiology1
Pathophysiology
  • PaO2 falls below 50 mmHg.
  • Stimulus from the hypoxia ultimately overrides the sedative effects of the hypercarbia, resulting in CNS stimulation.
  • Until unconscious, the victim experiences a great deal of panic.
  • During this time the victim makes violent inspiratory and swallowing efforts, resulting in copious amounts of water entering the mouth, posterior pharynx, and stomach.

Intermediate Lecture – Environmental Emergencies

pathophysiology2
Pathophysiology
  • This stimulates laryngospasm and bronchospasm.
  • This prevents the influx of water into the lungs (dry drowning).
  • If laryngospasm does not occur, then a significant amount of water does enter the lungs (wet drowning).
  • Laryngospasm or aspirated water aggravates the hypoxia, with coma ultimately ensuing.
  • Persistent anoxia results in a deeper coma.

Intermediate Lecture – Environmental Emergencies

pathophysiology3
Pathophysiology
  • Drowning and near-drowning are primarily due to asphyxia from airway obstruction in the lung secondary to the aspirated water or laryngospasm.

Intermediate Lecture – Environmental Emergencies

fresh water drowning
Fresh-Water Drowning
  • Large surface area of the alveoli and small airway allow a massive amount of hypotonic water to diffuse across and into the vascular space (hemodilution)
  • Produces a thickening of the alveolar walls with inflammatory cells, hemorrhagic pneumonitis and destruction of surfactant

Intermediate Lecture – Environmental Emergencies

fresh water drowning1
Fresh-Water Drowning
  • When capillaries of the alveoli are damage, plasma leak back into the alveoli, resulting in the accumulation of fluid in the small airway.
  • Leads to multiple areas of atelectasis with shunting and hypoxemia

Intermediate Lecture – Environmental Emergencies

sea water drowning
Sea-Water Drowning
  • Hypertonic nature of the fluid draws water from the bloodstream into the alveoli.
  • Sea water is 3-4 times more hypertonic than plasma.
  • Produces pulmonary edema, leading to profound shunting.

Intermediate Lecture – Environmental Emergencies

sea water drowning1
Sea-Water Drowning
  • Result is failure of oxygenation, producing hypoxemia
  • Respiratory and metabolic acidosis develop due to the retention of CO2 and developing anaerobic metabolism
  • Initial field treatment must be directed toward correcting the profound hypoxia

Intermediate Lecture – Environmental Emergencies

factors affecting survival
Factors Affecting Survival
  • Cleanliness of the water
  • Length of time submerged
  • Age and general health of the victim
  • Water temperature
  • Mammalian Diving Reflex

Intermediate Lecture – Environmental Emergencies

mammalian diving reflex
Mammalian Diving Reflex
  • When diving into cold water the victim reacts to the submersion of the face
  • Breathing is inhibited
  • Heart rate becomes bradycardic
  • Vasoconstriction develops in tissues relatively resistant to asphyxia
  • Cerebral and cardiac blood flow is maintained
  • Oxygen is sent and used only where it is immediately needed to sustain life
  • The colder the water, the more oxygen is diverted to the heart and brain

Intermediate Lecture – Environmental Emergencies

prehospital management3
Prehospital Management
  • Remove from water as quickly as possible.
  • Ventilation should be initiated while the patient is still in water.
  • Suspect head and neck injury if the patient experienced a fall or was diving.
  • Examine for airway patency, breathing, and pulse.
  • If indicated, begin CPR. Airway management should include proper suctioning and use of airway adjuncts.

Intermediate Lecture – Environmental Emergencies

prehospital management4
Prehospital Management
  • C-spine injury should be considered and treated accordingly.
  • Administer oxygen, consider rewarming (transport time greater than 15 minutes)
  • Heimlich maneuver is contraindicated.
  • Establish an IV
  • If indicated, defibrillation
  • ACLS protocols for normothermic patient or hypothermic.

Intermediate Lecture – Environmental Emergencies

nuclear radiation

NUCLEAR RADIATION

Intermediate Lecture – Environmental Emergencies

introduction2
Introduction
  • Incidence of radiation emergencies has increased in recent years due to the expansion of nuclear medicine procedures and commercial nuclear facilities.
  • Radiation: generic term applied to the transmission of energy.
  • Energy can include nuclear energy, ultraviolet light, visible light, heat, sound, and x-rays.
  • Radioactive substance emits ionizing radiation, such as a radiomuclide or radioisotope.

Intermediate Lecture – Environmental Emergencies

basic nuclear physics
Basic Nuclear Physics
  • Structure of an atom:
  • Protons: positively charged particles that form the nucleus of hydrogen and that are present in the nuclei of all elements
  • Neutrons: subatomic particles that are equal in mass to a proton, but lack an electrical charge.
  • Electrons: particles with negative electrical charges, revolving around the nucleus of an atom (beta particles).

Intermediate Lecture – Environmental Emergencies

basic nuclear physics1
Basic Nuclear Physics
  • Terms associated with nuclear medicine:
  • Isotopes: atoms in which the nuclear composition is unstable. Give off ionizing radiation.
  • Half-life: time required for half the nuclei of a radioactive substance to lose their activity due to radioactive decay

Intermediate Lecture – Environmental Emergencies

basic nuclear physics2
Basic Nuclear Physics
  • Four types of radiation:
  • Alpha Particles: slow-moving, low-energy particles that usually can be stopped by such things as clothing, and paper. Can produce serious effects if taken internally by ingestion or inhalation.
  • Beta Particles: smaller than alpha particles, but higher in energy. Can be stopped by aluminum and similar materials. Cause less local damage than alpha, but can be harmful if inhaled or ingested

Intermediate Lecture – Environmental Emergencies

basic nuclear physics3
Basic Nuclear Physics
  • Gamma Rays: more highly energized and penetrating than alpha and beta. Origin of gamma rays is related to that of x-rays. Extremely dangerous, carrying high levels of energy capable of penetrating thick shielding. Pass easily through clothing and the entire body, inflicting extensive cell damage. Protection is best provided by lead shielding.
  • Neutrons: more penetrating than the other types. Exposure causes direct tissue damage. Neutrons tend to be present only near a reactor core.

Intermediate Lecture – Environmental Emergencies

effects of radiation
Effects of Radiation
  • Ionizing radiation cannot be seen, felt, or heard
  • Need a Geiger counter to detect and measure the radiation given off
  • Rate of radiation is measure in roentgens per hour
  • Unit of local tissue energy deposition is called radiation absorbed dose (RAD)
  • Roentgen equivalent in man (REM) provides a gauge of the likely injury to the irradiated part of an organism
  • RAD and REM are equal in clinical value

Intermediate Lecture – Environmental Emergencies

effects of radiation1
Effects of Radiation
  • Ionizing radiation causes alterations in the body’s cell, primarily the genetic material (DNA).
  • Depending on dosage the changes can be in cell division, cell structure, and cellular biochemical activities.
  • Cell damage due to ionizing radiation is cumulative over a lifetime.
  • May be defects in offspring, an increased incidence of cancer, and various degrees of bone marrow damage.

Intermediate Lecture – Environmental Emergencies

effects of radiation2
Effects of Radiation
  • Biological effects:
  • Acute: effects appearing in a matter of minutes or weeks
  • Long-Term: effects appearing years or decades later

Intermediate Lecture – Environmental Emergencies

principles of safety
Principles of Safety
  • The amount of radiation received by a person depends upon the source of radiation, the length of time exposed, the distance from the source, and the shielding between the exposed person and the source.
  • Two basic types of ionizing radiation accidents:
  • Clean accident: exposed to radiation but is not contaminated by the radioactive substance, particles of radioactive dust, or radioactive liquids, gases, or smoke.

Intermediate Lecture – Environmental Emergencies

principles of safety1
Principles of Safety

2. Dirty accident: often associated with fire at the scene of a radiation accident – exposes the patient to radiation and contaminates him with radioactive particles or liquids.

Intermediate Lecture – Environmental Emergencies

prehospital management5
Prehospital Management
  • Park the vehicle upwind to minimize contamination
  • Look for signs of radiation exposure.
  • Use portable instruments to measure the level of radioactivity.
  • Normal principles of emergency care should be applied

Intermediate Lecture – Environmental Emergencies

prehospital management6
Prehospital Management
  • Externally radiated patients pose little danger to rescue personnel, initiate normal care procedures
  • Internally contaminated patients (ingested/inhaled) pose little danger to rescue personnel. Initiate normal care procedures
  • Externally contaminated patients (liquids, dirt, smoke) require decontamination, then initiate care
  • Patients with open, contaminated wounds require normal care.

Intermediate Lecture – Environmental Emergencies

diving emergencies

DIVING EMERGENCIES

Intermediate Lecture – Environmental Emergencies

introduction3
INTRODUCTION
  • SCUBA diving accidents are fairly uncommon, inexperienced divers have a higher incident rate of injury.
  • Emergencies can occur on the surface, three feet of water, or at any depth.
  • More serious emergencies usually follow a dive.

Intermediate Lecture – Environmental Emergencies

physical principles of pressure
Physical Principles of Pressure
  • Density of the water can be equated to pressure, which is defined as the weight or force acting upon a unit area.
  • Fresh water exerts a pressure of 62.4 pounds over an area of one square foot (salt water is 64 pounds). Stated as pounds per square inch (psi)
  • At sea level humans live in an atmosphere of air, or a mixture of gases, and they exert a pressure of 14.7 psi.

Intermediate Lecture – Environmental Emergencies

boyle s law
Boyle’s Law
  • The volume of a gas is inversely proportional to its pressure if the temperature is kept constant.

Intermediate Lecture – Environmental Emergencies

henry s law
Henry’s Law
  • The amount of gas dissolved in a given volume of fluid is proportional to the pressure of the gas with which it is in equilibrium.

Intermediate Lecture – Environmental Emergencies

common diving injuries
Common Diving Injuries
  • Diving injuries are due to either barotrauma (mechanical effect of the pressure differential), cerebral air embolism, compression illness, cold, panic, or a combination of the above.
  • Accidents generally occur at one of the following four stages of a dive:

Intermediate Lecture – Environmental Emergencies

injuries during descent
Injuries During Descent
  • Barotrauma, commonly called the “squeeze” becomes a concern during the descent.
  • Unable to equilibrate the pressure between the nasopharynx and the middle ear through the eustachian tube can result in middle ear pain.
  • Along with pain other S&S include ringing in the ears, dizziness, and hearing loss.
  • In severe cases, rupture of the ear drum can occur.

Intermediate Lecture – Environmental Emergencies

injuries during descent1
Injuries During Descent
  • Similar lack of equilibration can occur in the sinuses, producing severe frontal headaches or pain beneath the eye in the maxillary sinuses.

Intermediate Lecture – Environmental Emergencies

injuries on the bottom
Injuries on the Bottom
  • These involve nitrogen narcosis.
  • Due to nitrogen’s effect on cerebral function.
  • Diver may appear to be intoxicated and may take unnecessary risks.

Intermediate Lecture – Environmental Emergencies

injuries during ascent
Injuries During Ascent
  • Serious and life-threatening emergencies occur during the ascent.
  • Causes may be related to barotrauma and the inability to equilibrate inner ear pressure with nasopharyngeal pressure.
  • Most serious barotrauma during ascent is injury to the lung. (from 3 feet of water to a deep dive).
  • Injury results from diver holding their breath during ascent.

Intermediate Lecture – Environmental Emergencies

injuries during ascent1
Injuries During Ascent
  • During the ascent the air in the lung begins to expand.
  • If not exhaled the alveoli may rupture. Resulting in an air embolism.
  • May also include mediastinal and subcutaneous emphysema due to diffusion of the gas through the lung into the mediastinum and neck.
  • Pneumothorax is possible if the alveoli rupture into the pleural cavity.

Intermediate Lecture – Environmental Emergencies

general assessment of diving emergencies
General Assessment of Diving Emergencies
  • Early assessment and treatment of a diving injury is of more importance than trying to distinguish the exact problem.
  • Must develop the diving history or profile. This includes:
  • Time at which the signs and symptoms occurred
  • Type of breathing apparatus utilized
  • Type of hypothermia protective garment worn

Intermediate Lecture – Environmental Emergencies

diving history
Diving History
  • Parameters of the dive:

* Depth of dive

* Number of dives

* Duration of dive

  • Aircraft travel following a dive
  • Rate of ascent
  • Associated panic forcing rapid ascent
  • Experience of the diver
  • Properly functioning depth gauge

Intermediate Lecture – Environmental Emergencies

diving history1
Diving History
  • Previous medical diseases
  • Old injuries
  • Previous episodes of decompression illness
  • Use of medication
  • Use of alcohol
  • This history will assist in determining if the diver has incurred a pressure disorder

Intermediate Lecture – Environmental Emergencies

pressure disorders
Pressure Disorders
  • Known as barotrauma, meaning injuries caused by pressure.
  • Most barotrauma results from a pressure imbalance between the external environment and gasses within the body’s cavities.

Intermediate Lecture – Environmental Emergencies

pressure disorders decompression sickness bends
Pressure DisordersDecompression Sickness (Bends)
  • Condition that develops in divers subjected to rapid reduction of air pressure after ascending to the surface following exposure to compressed air.

Intermediate Lecture – Environmental Emergencies

pathophysiology4
Pathophysiology
  • Results as nitrogen bubbles enter the tissue spaces and small blood vessels.
  • Symptoms present when a diver rapidly ascends after being exposed to a depth of 33 feet or more for a time sufficient enough to allow the body’s tissues to be saturated with nitrogen.
  • Effects on the body can be direct or indirect.

Intermediate Lecture – Environmental Emergencies

direct effects
Direct Effects
  • Intravascular: blood flow will be decreased, leading to ischemia or infarct.
  • Extravascular: tissues will be displaced, which further results in pressure on neutral tissue.
  • Audiovestibular: air can diffuse into the audiovestibular system, causing vertigo.

Intermediate Lecture – Environmental Emergencies

indirect effects
Indirect Effects
  • Surface of air emboli may initiate platelet aggregation and intravascular coagulation
  • Extravascular plasma loss may lead to edema
  • Electrolyte imbalances may occur
  • Lipid emboli are released

Intermediate Lecture – Environmental Emergencies

presentation
Presentation
  • Decompression sickness divided into two types based on the presenting signs and symptoms.

Intermediate Lecture – Environmental Emergencies

type i
Type I
  • Usually referred to as the “bends”.
  • Patient experiences pain (joints).
  • Caused by expansion of gases present in the joint space.
  • Skin manifestations usually consist only of pruritus (itch).
  • Rash, spotted pallor, cyanosis, or pitting edema may occur.

Intermediate Lecture – Environmental Emergencies

type i1
Type I
  • Treatment mainly consists of oxygen inhalation but could require recompression.
  • Prognosis is usually good.

Intermediate Lecture – Environmental Emergencies

type ii
Type II
  • Broad spectrum of complaints and could include symptoms of Type I
  • Paresthesias * Paralysis
  • Dizziness or vertigo * Headache
  • Nausea * Dyspnea
  • Auditory disturbances * Chest Pain
  • Vestibular disturbances * Loss of consciousness

* Hemoptysis

Intermediate Lecture – Environmental Emergencies

decompression sickness
Decompression Sickness
  • Pulmonary complications of decompression sickness, referred to as “the chokes” are extremely serious.

Intermediate Lecture – Environmental Emergencies

general symptoms of decompression sickness
Extreme fatigue

Joint pain

Headache

Lower abdominal pain

Chest pain

Urinary dysfunction

Vertigo and ataxia

Pruritus

N/V

Back pain

Priapism

Paresthesias

Paralysis

Dysarthria

Frothy, reddish sputum

Dyspnea

General Symptoms of Decompression Sickness

Intermediate Lecture – Environmental Emergencies

prehospital management7
Prehospital Management
  • Patients usually seek medical attention within 12 hours of ascent from a dive
  • S&S developing more than 36 hours after a dive cannot reasonably be attributed to decompression sickness
  • Oxygen therapy and possible recompression

Intermediate Lecture – Environmental Emergencies

prehospital management8
Prehospital Management
  • Assess ABCs
  • CPR if required
  • Oxygen (NRM or intubate if necessary)
  • Left lateral Trendelenburg position if possible
  • Protect from excessive heat, cold, wetness, or noxious fumes
  • Fruit juices or balanced salt solutions if conscious
  • IV’s (crystalloid of choice)
  • CNS involvement administer decadron, heparin, valium
  • If flown, lowest altitude possible and take diving equipment with you for analysis

Intermediate Lecture – Environmental Emergencies

pulmonary overpressure accidents
Pulmonary Overpressure Accidents
  • Lung overinflation due to rapid ascent is common cause of of diving emergencies.
  • Air expansion on ascent can rupture the alveolar membranes.
  • Resulting in hemorrhage, reduced oxygen and carbon dioxide transport, and capillary and alveolar inflammation.
  • Air can escape and cause pneumothorax and tension pneumothorax, subcutaneous emphysema, or pneumomediastinum

Intermediate Lecture – Environmental Emergencies

air embolism
Air Embolism
  • Any person using SCUBA equipment presenting with neurologic deficits during or immediately after ascent, should be suspected of air embolism
  • Form of barotrauma of ascent.
  • Very serious condition in which air bubbles enter the circulatory system through rupture of small pulmonary vessels.
  • Air can also be trapped in blebs, air pockets, within the pulmonary tissue

Intermediate Lecture – Environmental Emergencies

air embolism1
Air Embolism
  • Bubbles can be transported to the heart and the brain, where they may lodge and obstruct blood flow, causing ischemia and possibly infarct.
  • S&S include:
  • Rapid and dramatic onset
  • Sharp, tearing pain
  • Paralysis (frequently hemiplegia)
  • Cardiac and pulmonary collapse
  • Unequal pupils
  • Wide pulse pressure

Intermediate Lecture – Environmental Emergencies

air embolism prehospital management
Air EmbolismPrehospital Management
  • Assess ABCs
  • Administer oxygen by NRM
  • Place patient in left lateral Trendelenburg position
  • Monitor vital signs frequently
  • Administer IV fluids (KVO)
  • Administer a corticosteroid agent
  • Transport to recompression chamber ASAP

Intermediate Lecture – Environmental Emergencies

pneumomediastinum
Pneumomediastinum
  • Release of gas through the visceral pleura into the mediastinum and pericardial sac.
  • S&S include:
  • Substernal chest pain
  • Irregular pulse
  • Abnormal heart sounds,
  • Reduced blood pressure/narrowing pulse pressure
  • Change in voice
  • May or may not be evidence of cyanosis

Intermediate Lecture – Environmental Emergencies

pneumomediastinum prehospital management
PneumomediastinumPrehospital Management
  • Administration of high-concentration oxygen via nonrebreathing face mask
  • Start IV
  • Transport
  • Treatment generally ranges from observation to recompression

Intermediate Lecture – Environmental Emergencies