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Environmental Emergencies

Paramedic Program

Chemeketa Community College

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Objectives

Describe the physiology of thermoregulation

Discuss the risk factors, pathophysiology, assessment findings, and management of specific hypothermic conditions and frostbite.

Discuss the risk factors, pathophysiology, assessment findings, and management of drowning and near-drowning

Discuss the risk factors, pathophysiology, assessment findings, and management of diving emergencies and high-altitude illness

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Terms

Acute mountain sickness Afterdrop Boyle’s law Core body temperature Dalton’s law Decompression sickness Drowning Frostbite Frostnip Heat cramps Heat exhaustion Heat stroke

Henry’s law High-altitude pulmonary

edema High-altitude cerebral

edema Homeostatis Near drowning Nitrogen narcosis Thermal gradient Thermogenesis Thermolysis Thermoregulation Trenchfoot

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Environmental Emergencies

A medical condition caused or exacerbated by the weather, terrain, atmospheric pressure or other local factors

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Risk Factors

Age General health Fatigue Predisposing medical conditions Medications - Rx/OTC

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Environmental factors

Climate Season Weather Atmospheric pressure Terrain

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Types of environmental illnesses

Heat Cold Pressurization Localized injuries

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General Pathophysiology, Assessment, Management

Homeostasis Normal Evaluation

Oral Axillary Tympanic Rectal Tactile

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Thermoregulation

Regulatory center – Posterior hypothalamus Peripheral thermoreceptors Central thermoreceptors Metabolic rate

Basal Exertional Caloric requirements

Core temperature 37 deg. Celsius 98.6 deg. Fahrenheit

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Thermal gradient

The difference in temperature between environment and body Ambient temperature Infrared radiation Relative humidity

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Thermogenesis

Muscular Baseline Exertion Shivering

Metabolic Sympathetic stimulation Processing of food and nutrients

Endocrine Role of hormones in setting basal rate

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Thermolysis

Vasodilation Perspiration

Ineffective if relative humidity is 75% or greater. Decrease in heat production Increased cardiac output Increased respiratory rate

Conduction, Convection, Radiation, Evaporation, Respiration

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Heat controlling mechanisms

Nervous feedback mechanisms regulate body temperature Hypothalamus Skin

Mostly cold receptors Mucous membranes Selected deep tissues

Spinal cord Abdominal viscera Great veins

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Heat Illness

General signs and symptoms Diaphoresis Posture Increased skin temp. Flushing Altered mentation Altered level of consciousness

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Physiology of Heat Gain And Loss

Heat gain

Metabolic heat production Increased metabolic activity

Environmental heat gain Heat transfer from environment

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Heat Loss Metabolic heat loss

Increased thermolysis from vasodilation

Environmental heat loss Increased thermolysis from heat transfer

Heat

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Predisposing factors Age

Peds Elders

Heat

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General health and meds

Diabetes Autonomic neuropathy interferes with vasodilation and

perspiration - may interfere with thermoregulatory input Antihypertensive meds

Diuretics - predispose to dehydration Beta blockers - interfere with vasodilation; reduce

capacity to increase heart rate; may interfere with thermoregulatory input

Psychotropic medications and antihistamines All interfere with central thermoregulation Antipsychotics Antihistamines Phenothiazines

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Length of exposure Intensity of exposure Environmental

Humidity Wind

Preventative measures Adequate fluid intake Acclimatize; results in more perspiration with

lower salt concentration; increases fluid volume in body.

Heat

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Hyperthermia Heat cramps

Muscle cramps; 2ndary to rapid change in extracellular fluid osmolarity resulting from sodium and water losses. Due to dehydration and overexertion Presents with

Cramps in fingers, arms, legs, abdominal muscles. Generally good mentation, Hot sweaty skin, Tachycardia, Normal BP Normal core temperature

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Treatment Remove from environment Massage cramped muscle Apply moist towels to forehead and over

cramped muscles Increase fluid and sodium intake Consider IV with NS or LR, transport if s/s

persist

Heat (cont.)

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Heat Exhaustion

Most common heat-related illness

History of exposure to hot weather

necessary for accurate assessment

Person may lose 1 – 2 liters of water/hour.

Each liter lost contains 20-50 mEq of sodium

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Presents with: Increased CBT with some neuro deficit Sweating Decreased fluid intake Decreased urine output Tachycardia N/V/D Dizziness, transient syncope H/A Muscle cramps Dehydration Orthostatic hypotension

Heat Exhaustion

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Treatment Rest Remove enough clothing for cooling Fan skin 1 – 2 IV’s: IV Fluids; NS or LR High-flow oxygen Supine position Transport

S/S that don’t resolve are predictive of impending heatstroke

Heat Exhaustion

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Heat Stroke

Increased CBT with significant neuro deficit Organ damage

Brain, liver, kidneys Predisposing conditions include age,

diabetes, other medical conditions increased CBT due to deficient

thermoregulatory function

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Exertional

Commonly presents in people in good

health

Increased CBT due to overwhelming heat

stress

Excessive ambient temp.

Excessive exertion, prolonged exposure,

poor acclimatization

Heat Stroke

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Presents with: Hot, Red, Dry skin Irrational or unconscious Rectal temperature 105 deg. F or higher Tachycardia Bradycardia Hypotension with low or absent diastolic Rapid, shallow respirations Airway compromise Seizures Cardiac arrest

Heat Stroke

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Treatment Cool rapidly; pack in ice and/or wrap in wet

sheets Apply cold packs to armpits, groin, behind

knees, on wrists, ankles, behind neck High flow oxygen with airway management 1 – 2 IV’s: NS or LR, wide open Diazepam or Versed to control seizures Transport rapidly

Heat Stroke

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Dehydration in heat disorders

Common syndrome Leads to orthostatic hypotension

N/V/D Vision disturbances Decreased urine output Poor skin turgor Signs of hypovolemic shock May occur with s/s of heatstroke

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Treatment

High-flow oxygen

1 – 2 IV’s: NS or LR titrated to B/P, if BS

clear, dry

Dehydration

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Water Intoxication

Occurs when patient in hot environment

drinks water at a rate that exceeds fluid

loss from sweating and fails to replace

sodium losses.

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Presents with: Normal vitals with negative orthostatics Chills Loss of coordination N/V H/A Altered mentation Hx: greater than one liter/hour Urinary frequency, dilute urine

Water Intoxication

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Treatment

Encourage patient to eat foods high in sodium

Restrict further fluid intake

Unresponsive pt’s: follow protocol for

unconscious, unresponsive pt., IV tko.

Water Intoxication

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Pyrexia (Fever)

Body temperature above normal Hx of infection or illness Neuro sx may present If unsure, tx for heatstroke Treatment

Remove from environment Active cooling

Watch for reflex hypothermia Use tepid water

Fluid therapy Oral: Add some salt IV: 0.9% NaCl

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Hyperpyrexia

Core body temperature above 106 deg. F. Causes:

Hot baths Hot air Reaction to infection Some develop hyperpyrexia within 24 hours after

surgery Rare cause: Administration of succinylcholine

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Hypothermia - Body core temperature < 97.0 deg. F Environmental causes Other causes:

Hypothyroidism Brain tumors, head trauma MI, Diabetes, Hypoglycemia, Drugs, Poor

nutrition, Sepsis. Geriatrics also contribute Meds that interfere with thermogenesis

Narcotics, alcohol, barbiturates Antiseizure meds Antihistamines, other allergy meds Antipsychotics, sedatives, antidepressants Aspirin, acetaminophen, NSAIDs

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Fatigue, exhaustion Length of exposure Intensity of exposure Environmental

Humidity Wind Temperature

Hypothermia

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Hypothermia

Onset

Acute (immersion)

Subacute (exposure)

Chronic (urban)

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Mild hypothermia: Body core temp. 94 – 97 deg. F.

Presents with: Peripheral vasoconstriction Increase in sympathetic nervous discharge,

catecholamine release, basal metabolism. HR BP RR Shivering until CBT about 86 deg. F, Glucose

depleted Mood changes

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Treatment

Protect against heat loss and wind chill Add heat to head, neck, chest, groin Blankets Skin-skin contact

NO alcoholic or caffeine beverages or nicotine

Warm oral fluids and sugar

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Moderate hypothermia: Body core temp. 86 – 94 deg. F

Presents with: Peripheral vasoconstriction

Increase in sympathetic nervous discharge,

catecholamine release, basal metabolism.

HR

BP

RR

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Significant ECG changes Prolonged PR, QRS, QT intervals Absent P waves ST-segment, T-wave abnormalities J waves (Osborn waves)

Shivering until CBT about 86 deg. F, Glucose depleted

Mood changes

Moderate hypothermia

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Treatment Remove all wet clothing; Rewarm

Add heat to head, neck, chest, groin Consider respiratory rewarming Do not give alcohol, caffine, nicotine Protect against heat loss and wind chill

Maintain horizontal position Avoid rough movement and excess activity Monitor cardiac rhythm Provide warm oral fluids and sugar AFTER

uncontrolled shivering stops and pt. is rewarming

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Severe hypothermia: Body core temp. less than 86 deg. F

Presents with: Disorientation, confusion, irrational behavior May become comatose Shivering usually stops May appear pulseless, apneic

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Treatment Assess pulse, respirations for at least 30

seconds q 1-2 minutes Begin CPR if pulseless, apneic; follow ACLS

guidelines Provide warmed, humidified oxygen Warm IV fluids only <84 deg. F CBT; do not give IV meds >84 deg. F CBT; give IV meds at longer

intervals GENTLE handling, especially when rewarming

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Continue resuscitation efforts until pt. is rewarmed to at least 86 deg. F. CBT

Do not attempt warming in the field unless the patient is more than 15 minutes from a medical facility If rewarming, use water 103-105 deg.

A patient is not considered dead until warm!

Treatment

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Rewarming shock - Afterdrop Reflex vasodilation

Resuscitation considerations BLS

Take vitals longer

CPR

Oxygen

AED

Treatment (cont.)

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ACLS Effects of cold on meds Orotracheal intubation Risks of Vfib related to depth and duration

of hypothermia Be gentle Impossible to defibrillate a heart colder

than 86 degrees Lidocaine and procainamide paradoxically

lower fibrillatory threshold and increase resistance to defibrillation

Bretylium and Mag. Sulfate may be effective

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Transport considerations

Gentle

Transport with head level or slightly down

Destination considerations

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Frostbite

Superficial - frostnip Some freezing of epidermal tissue Initial redness followed by blanching Diminished sensation

Deep Freezing of epidermal and Subcutaneous Layers White, hard, loss of sensation

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Treatment

Transport Rewarm rapidly if transport delayed

104o max Don’t rewarm if danger of refreezing Immobilize, elevate Bandage with bulky, dry, sterile dressings Don’t puncture blisters

Don’t massage frozen area Administer Morphine Sulfate, titrated to pain

relief

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Trenchfoot

Similar to frostbite but at temp. above freezing

Assoc. w/ prolonged exposure to moisture

S/S similar to frostbite

Blisters may form; pain

Tx: Dry and warm; aerate

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Near Drowning

Statistics: 80,000 each year 85% male 2/3 non-swimmers

Submersion episode with at least transient

recovery

Mammalian diving reflex

Stages of drowning

                           

                  

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Wet vs. Dry drownings Fluid in posterior oropharynx stimulates

laryngospasm Aspiration occurs after muscle relaxation Suffocation occurs with or without aspiration Aspiration presents as airway obstruction 15% of drownings are dry

Fresh vs. Salt water No difference in metabolic result No difference in prehospital treatment

Near Drowning

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Salt Water draws plasma fluid

into alveoli

Surfactant Destruction;Alveolitis;

Destruction of capillarymembrane

Aspiration-Fresh Water

Aspiration-Salt Water

Water rapidly leaks to capillary

bed and circulation

RespiratoryRespiratoryFailureFailure

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Hospital Findings

Salt water: hypertonic fluid

Rapid shift of plasma and fluid into alveoli and

interstitial spaces

Results in pulmonary edema, hypoxia

Sx delayed 1 – 6 hours

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Fresh water Hypotonic to plasma and passes into

circulation. If >20 mL/kg, blood volume increases;

hemolysis Surfactant destruction = reduced compliance,

alveolar collapse, hypoxia Severe electrolyte abnormalities

Hospital Findings

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Hypothermic considerations in near-drownings

Common treatment in all near-drowning patients May be organ protective Always treat hypoxia first

Treatment Airway

Questionable data to support prophylactic abdominal thrusts

Trauma

                          

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Post-resuscitation Complications

ARDS or renal failure

S/S may not appear for 24 hours

All near-drowning patients must be

transported

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Diving Emergencies

Boyle’s law At a constant temperature, volume of gas inversely

related to its pressure (PV=K) Dalton’s law

The pressure exerted by each gas in a mixture is the same as it would exert if alone (Pt=PO2+PN2+Px)

Henry’s law At a constant temperature, solubility of gas in a

liquid solution is proportionate to partial pressure of the gas (%X=Px/Pt x 100)

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Increased pressure dissolves gasses into blood

Oxygen metabolizes Nitrogen dissolves Primary etiology - rapid ascent

Decompression Excess nitrogen bubbles out of solution on

depressurization Occurs in joints, tendons, spinal cord, skin, brain,

inner ear

Diving Emergencies

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Diving Emergencies

Barotrauma Tissue damage results from

compression or expansion of gas spaces when gas pressure in the body is different from ambient pressure.

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Barotrauma of Descent

(Squeeze) Usually results from blocked eustachian tube.

Air trapped in non-collapsable chambers is compressed; Vascular engorgement Edema Hemorrhage of exposed tissue

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Barotrauma of Descent

Occurs in Ears, sinuses, lungs, airways, GI tract, Thorax, Teeth

Presentation Pain - severe, sharp Sensation of fullness H/A Disorientation Vertigo Nausea Bleeding from nose or ears

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Management of Barotrauma of descent Perform gradual ascent to shallower depths

Prehospital care supportive

Transport with head elevated

Treat with rest, decongestants,

antihistamines, antibiotics, possibly surgical

repair

Barotrauma of Descent

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Barotrauma of Ascent

Reverse squeeze Volume of air in pressurized spaces expands

as ambient pressure decreases (Boyle’s law) Compressed gas at 33 ft (2 atmospheres)

doubles at surface (1 atmosphere) because pressure is ½ of 33 ft.

Last 6 feet of ascent have greatest potential for volume expansion

Most common cause is breath-holding

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Conditions resulting from barotrauma of ascent

Pulmonary Overpressurization Syndrome may occur Leads to alveolar rupture and extravasation of air

Presents with Gradually increasing chest pain Hoarseness Neck fullness Dyspnea Dysphagia Subcutaneous emphysema

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Air Embolism

Suspect when diver suddenly loses consciousness immediately after surfacing

Pneumomediastinum Subcutaneous Emphysema Pneumopericardium Pneumothorax Pneumoperitoneum Systemic arterial air embolism

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Air Embolism

Presents with Stroke-like sx: Focal paralysis or sensory

changes Aphasia Confusion Blindness or other visual disturbances Convulsions Loss of consciousness

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Management of conditions

Tension pneumothorax Needle chest decompression

Air embolism Hyperbaric recompression If intubated, fill cuff with saline Transport left lateral recumbent position with 15

degree elevation of thorax Other management

Oxygen administration, observation, transport to hyperbaric facility

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Decompression Sickness“The Bends”

Multi-system disorder Nitrogen in compressed air converts from

solution to gas, forming bubbles (Henry’s law)

Results from too-rapid ascent Results in vascular occlusion, poor tissue

perfusion, ischemia Joints and spinal cord most often effected

                                                                                                         

   

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Decompression Sickness

Suspect decompression sickness in any diver with sx within 12-36 hours after dive.

Prehospital care Supportive High flow oxygen IV fluids Recompression chamber

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Nitrogen Narcosis

Nitrogen becomes dissolved in solution; crosses blood-brain barrier and produces neurodepressant effects (mimics alcohol) Most common at depths of 70-100 feet Intoxication Treatment

Self resolving Return to shallow depths Supportive care Transport for evaluation

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High-Altitude Illness

Exposure to high altitude may exacerbate

chronic medical conditions

Etiology - over 8000 feet above sea level

Prevention Gradual ascent,

Limited exertion,

High carbohydrate diet,

Meds

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Acute Mountain Sickness (AMS)

H/AMalaise

AnorexiaVomitingDizzinessIrritability

Impaired memoryDyspnea on exertion

High-altitudeCerebral Edema

(HACE)

H/AAtaxia

Altered mentationConfusion

HallucinationsDrowsiness

StuporComa

High-altitude Pulmonary

Edema (HAPE)

SOBDyspnea

Cough (/c or /sFrothy sputum)

Generalized weaknessLethargy

Disorientation

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AMS Sx within 4-6 hrs Attains maximum severity in 24-48 hrs Abates on 3rd or 4th day

HAPE Sx in 24-72 hrs; often preceded by strenous

exercise HACE

Most severe form Progression from AMS; onset 12 hrs to 3 days

High-Altitude