Curriculum Update: Environmental Conditions

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Curriculum Update Environmental Conditions

• Condell Medical Center
• EMS System
• June/July 2005

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Objectives

• Upon successful completion of this module, the
  EMS provider should be able to
• discuss the pathophysiology of environmental
  emergencies
• list signs and symptoms of a variety of
  environmental emergencies
• describe the interventions required for a variety
  of environmental emergencies
• describe the role of the EMS provider at the
  scene of a hazardous materials incident
• successfully complete the quiz with a score of
  80 or better

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Definitions

• Environment - all of the surrounding external
  factors that affect the development and
  functioning of a living organism
• Environmental emergencies - a medical condition
  caused or exacerbated by environmental factors
  (ie temperature, weather, terrain, atmospheric
  pressures) acting on the body and creating
  stresses the body is unable to compensate for
• Homeostasis - attempt to maintain a constant
  suitable condition within the body

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• Special rescue resources
• may need to be considered based on the need of
  the rescue situation
• special rescue resources, or the environmental
  conditions alone, may increase the risk of injury
  to the rescuer
• safety of the EMS provider is always considered a
  top priority
• Increase in ease of travel
• patient may not have suffered the insult in your
  locale but now brings their problem to your
  town (diving emergencies, high altitude sickness)

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Hyperthermia

• Definition
• a state of unusually high body temperature
• normal body temperature is 98.6o F (37o C)
• Most common causes of hyperthermia
• transfer of heat from the environment to the
  individual and the body cannot compensate for it
• occasionally the excess heat is generated from
  within the body

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Body Temperature

• Rectal temp most representative of core temp
• normal is 98.6o F (37oC)
• Oral temp - slightly lower than rectal
• Axillary temp - barely lower than oral
• Extremities - hands feet cooler than arms
  legs
• Skin temperature - head, chest, abdomen warmer
  than extremities
• Exercise - increases body temperature up to 20
  times warmer than at rest

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Predisposing Risk Factors

• Age - very young elderly are less tolerant of
  temperature variations
• Poor general health status (poorer reserves)
• Fatigue
• Certain predisposing medical conditions
• Certain medications - including prescription and
  over-the-counter ? sensitivity
• Length intensity of exposure
• Ability to acclimize to the environment

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Regulation Control of Body Temperature

• Hypothalamus - region in the brain controls a
  large number of bodily functions
• main function - homeostasis
• method - receives inputs from the body, initiates
  compensatory changes as needed to maintain
  balance
• Body is constantly generating heat so must
  constantly be finding a way to lose heat

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Hypothalamus Regulation

• Signals sent to autonomic nervous system
• affects parasympathetic sympathetic nervous
  systems
• control exerted over heart rate, vasoconstriction
  of blood vessels, digestion process, sweating
• Endocrine signals (chemicals) sent to through
  the pituitary gland
• hypothalamus can control every endocrine gland
• B/P regulated (release of vasopressin causing
  vasoconstriction changes in body temperature,
  rate of metabolism, circulating adrenaline levels)

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Process of Heat Transfer

• Conduction - flow of heat energy between 2 or
  more solids in close contact
• effectiveness dependent upon gradient between
  body temp temp of surrounding environment
• Radiation - emission of infrared heat rays
• Evaporation of perspiration via sweating
• sweating begins at 98.6oF (37oC) increases as
  needed
• Convection - movement of heat by currents (wind)

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Hypothalamic Responses

• When body temperature increases, signals sent to
• increase heart rate myocardial contraction
  force
• expand the skin surface to radiate more heat
• produce sweat to cool via evaporation
• Environmental considerations/influences
• in high relative humidity, sweat does not
  evaporate as quickly
• radiation of heat off of skin slows when gradient
  between skin and air is minimal
• in exercise, muscles generate x20 more heat

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Role of Dehydration in Heat Emergencies

• Dehydration occurs due to
• decreased intake
• increased loss of fluids thru sweating
• Vasodilatation inhibited by dehydration so skin
  surface does not increase and therefore cooling
  mechanisms not functional
• Dehydration causes nausea, vomiting, abdominal
  distress, visual changes, ? urine output, poor
  skin turgor, hypovolemic shock

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Heat Disorders

• Heat (muscle) cramps
• caused by overexertion dehydration
• sweating involves loss of water electrolytes
• Signs symptoms
• cramps in fingers, arms, legs, or abdominal
  muscles
• mentally alert with complaint of weakness
• dizziness or faint feeling
• stable vital signs
• body temp normal or slightly elevated
• skin moist and warm

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Region X SOP Treatment - Heat Cramps

• Move patient to cool environment
• Do not massage cramped muscles
• massaging may increase pain
• (gentle stretching is acceptable)
• Transport

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• Heat exhaustion
• acute reaction to heat exposure
• loss of water sodium
• general vasodilatation leads to decreased
  circulating blood volume, venous pooling, reduced
  cardiac output
• Signs and symptoms
• related to dehydration sodium loss
• ? body temp ? perspiration cool clammy skin
• rapid shallow breathing
• weak pulse syncope
• headache, weakness, anxiety, impaired judgement

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Region X SOP Treatment - Heat Exhaustion

• IV fluid challenge
• adult - 200 ml increments
• children lt 13 years - 20 ml/kg
• Gradual cooling
• move to cool environment
• remove as much extra clothing as possible
• supine position, feet elevated
• Transport

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• Heat Stroke
• true environmental emergency hypothalamic
  regulation lost leading to uncompensated
  hyperthermia
• temps generally gt 105oF (40.6o C)
• cell death occurs damage to brain, liver,
  kidneys
• Classic heatstroke - most common in those with
  chronic illness deficiency in thermoregulatory
  system
• Exertional heatstroke - most common in those with
  good health who have increased their core body
  temp due to ? heat stress

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• Signs symptoms of heat stroke
• hot skin (dry with classic heat stroke, still
  moist with exertional heat stroke)
• very high core temperature (usually gt105oF
  -40.6oC)
• deep respirations becoming shallow
• rapid, full pulse slowing later
• hypotension
• confusion or disorientation or unconsciousness
• possible seizures

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Region X SOP Treatment -Heat Stroke

• IV fluid challenge
• adult - 200 ml increments
• children lt 13 years - 20 ml/kg
• Rapid cooling procedure
• start with heat exhaustion guidelines
• continue to cool with cool water towels or sheets
  placed on patient fan body to ? air currents
• cold paks to lateral chest wall, axilla, carotid
  arteries, temples, behind knees

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Additional Environmental Challenges

• Your patient may not always suffer the initial
  insult in your town but with ease of travel, can
  be injured elsewhere and arrive back home with
  a medical crisis that you now have to handle
• Environmental emergencies that may be brought
  home
• diving emergencies
• high altitude sickness

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Diving Emergencies

• Diving emergencies are relatively rare and can
  occur at any depth of water from the surface on
  downward to great depths
• Water is an incompressible liquid fresh water
  density is 62.4 pounds per cubic foot salt water
  has a density of 64.0 pounds per cubic foot

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Physical Laws Affecting Diving Accidents

• ?Boyles Law - volume of gas is inversely
  proportional to its pressure if temp constant
• as pressure increases, gas is compressed into a
  smaller space
• ?Daltons Law - total pressure of a mixture of
  gases is equal to the sum of the partial
  pressures of the individual gases
• air we breathe is a mixture nitrogen (78), O2
  (21), CO2 traces argon, helium, other gases (1)

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• ?Henrys Law - amount of gas dissolved in given
  volume of fluid proportional to pressure of the
  gas above it
• when we descend below sea level, the pressure on
  us increases, gases in the air we breathe tend to
  dissolve in liquids (mainly blood plasma) and
  tissues of the body
• oxygen metabolizes (used up in normal metabolism
  of the cells) so only small amount is available
  in descent to dissolve in blood tissues
• nitrogen is inert gas, not used by body,
  available to dissolve in blood tissues as
  person descends

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Pathophysiology of Diving Emergencies

• Controlled ascent
• as pressures decrease, dissolved gas comes out of
  blood tissues slowly, escapes via respirations
• Rapid ascent
• dissolved gases (mostly nitrogen) come out of
  solution expand quickly bubbles formed in
  blood, brain, spinal cord, skin, inner ear,
  muscles, joints
• once formed in tissues, bubbles difficult to
  remove

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Diving Emergencies

• Most dramatic most life threatening diving
  emergencies are from lung expansion
• Most problems of lung expansion will occur due
  to
• pathological air trapping in someone with
  preexisting lung disease (ie COPD)
• breathholding during ascent

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Diving Injuries

• Barotrauma
• injuries caused by changes in pressure
• commonly called the squeeze
• most commonly affects ears sinuses
• air trapped in noncollapsible chambers is
  compressed vacuum effect occurs
• diver complains of severe sharp pain, vascular
  engorgement, edema, hemorrhage of exposed tissues
• prehospital care - supportive

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• ?Air embolism
• usually occurs when ascent too rapid or
  breathholding occurs during ascent from any depth
• expanding air disrupts tissues air is forced
  into circulatory system
• air passes thru left side of heart lodged in
  small arterioles
• distal circulation occluded
• note sudden loss of consciousness after surfacing
• rapid transport ? left lateral side lying with
  15o head elevation or ? new evidence suggests
  horizontal especially if neurological
  abnormalities

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• ?Nitrogen narcosis
• dissolved nitrogen crosses the blood/brain
  barrier produces neurodepressant effects
  similar to alcohol
• diver may appear intoxicated
• may take unnecessary risks, exercise poor
  judgement
• effects reversed during ascent
• EMS may need to care for injuries that may have
  occurred during the dive and possibly related to
  actions from poor decision making

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• Decompression sickness - the bends
• staged ascent required for dives over 40 feet
• air was compressed during descent on ascent air
  pressure is reduced if ascent is too rapid,
  inert nitrogen gas comes out of solution and
  expands quickly. Bubbles are formed in the blood,
  brain, spinal cord, skin, inner ear, muscles, and
  joints
• net effect seen is poor tissue perfusion
  ischemia
• difficult to remove nitrogen bubbles once formed
• symptoms can present 12-36 hours post dive
• extreme joint pain, rashes, itching, bubbles
  under skin
• EMS care - 100 O2, IV, monitor, rapid transport

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Myths Facts Related to Diving

• ?Diving after pneumothorax recovery
• not a problem after pneumothorax from blunt
  trauma is healed
• following history from penetrating trauma, risk
  of repeat pneumothorax increased and diving not
  recommended
• history of spontaneous pneumothorax has high risk
  for reoccurrence during diving diving not
  recommended

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• ?Nosebleed while diving
• generally occurs when pressures not equalized in
  sinuses middle ear
• superficial blood vessels rupture
• not painful, sight of blood can be frightening
• avoided by performing valsalva maneuvers while
  descending
• avoid diving with acute problems like sinus
  trouble, allergies, broken nose, deviated septum,
  presence of colds

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• ?Perforated ear drum
• can dive after healing occurs (usually 2 months)
• chronic perforations should not dive
• barotrauma to the middle ear can present with a
  sensation of pressure or fullness, decreased
  hearing, ringing in the ears
• ?Diving after flying
• mild dehydration from a long flight can
  predispose a diver to decompression illness
  (washout of inert gases like nitrogen less
  effective in dehydration)
• recommended time restriction from diving until
  flying is 12 hours to best avoid decompression

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• ?Diving after dental surgery
• air can be forced into subcutaneous tissues by ?
  pressures in mouth
• post-surgical pain can impede ability to hold
  regulator in place
• diver must be able to hold mouthpiece in place
  without pain or discomfort
• pain medication may affect decision making
  capabilities
• pain medication and diving not a good mix
• wait a minimum of 4-6 weeks for healing

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• ?Developing subcutaneous emyphysema after diving
• there can be an increase in the amount of air
  pressure in the air spaces of the lung
• air bubbles may escape through lung tissue
• escaped air may travel up to the shoulder, neck,
  or face
• tissue swelling crackling bubbling feel to skin
• condition is not painful
• patient needs to be evaluated by a physician to
  determine exact cause of the subcutaneous
  emphysema

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Diver's Alert Network (DAN)

• Nonprofit organization
• operated by Duke University Medical Center
• Specializes in diving-related illness
• Available for consultation and referral
• Can be reached at [phone].

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High Altitude Illness

• Partial pressure of oxygen decreases as you
  increase your altitude
• air is thinner so less air is in the atmosphere
• less oxygen in lungs ?less oxygen in blood
• Less oxygen available
• triggers new problems
• aggravates existing conditions (ie angina,
  congestive heart failure, COPD, hypertension)
• Hypoxic environment causes decreased exercise
  performance

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Acclimatization to Altitudes

• Definition - process of the body adjusting to the
  decreasing availability of oxygen
• a slow process, takes place over several days
• Normal physiological changes noted
• hyperventilation
• shortness of breath during exertion
• increased urination
• changed breathing pattern at night
• frequent awakening at night
• weird dreams

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High Altitude Pearls

• High altitude sickness - not dependent on age or
  physical condition of person anyone ascending
  too rapidly and not allowing acclimatization to
  the altitude can develop signs and symptoms
• High altitude EMS in Lake County, Illinois
• patient will not come home and then call you with
  these complaints
• signs symptoms will be present at the higher
  altitude and must be dealt with at that location

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Acute Mountain Sickness (AMS)

• Common high-altitude illness (rarely lt 8000 feet)
• Is bodys intolerance of hypoxic environment
• Results from rapid ascent of an unacclimatized
  person to higher altitudes
• Usually develops in susceptible individuals
  within four to six hours of reaching high
  altitude
• Attains maximal severity within 24 to 48 hours
• Abates on the third or fourth
  day after exposure with
  gradual acclimatization

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Signs and symptoms of AMS

• Headache the most common symptom
• Loss of appetite
• Nausea vomiting
• Dizziness or light-headedness
• Irritability
• Impaired memory, confusion
• Dyspnea on exertion breathlessness
• Sleep disturbances
• Staggering gait

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Treatment of AMS

• Often self-limiting problem - stop ascending
  until acclimatized often improves 1-2 days
• Descent to as low an altitude as necessary will
  help achieve quicker relief
• Generally treatment includes rest, fluids,
• mild analgesics
• Oxygen administration
• Definitive treatment after physician
  evaluation may involve
• Diuretics and steroids
• Hyperbaric therapy

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High-altitude pulmonary edema (HAPE)

• Thought to be caused at least in part by
  increased pulmonary artery pressure that develops
  in response to hypoxia
• Increased pressure results in
• ?release of leukotrienes, which increase
  pulmonary
• arteriolar permeability
• ? leakage of fluid into extravascular locations
• Initial symptoms usually begin 24 to 72 hours
  after exposure to high altitudes and are often
  preceded by strenuous exercise

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Signs and symptoms of HAPE

• Shortness of breath
• Dyspnea
• Cough (with or without frothy sputum)
• Generalized weakness
• Lethargy, extreme fatigue
• Disorientation
• Physical findings in patients include
• ? respiratory rate, crackles, rhonchi,
  tachycardia, and cyanosis

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Emergency care of HAPE

• Oxygen administration
• Immediate descent to lower altitude to where the
  patient felt comfortable upon wakening
• Patients do not return to Illinois with active
  signs symptoms of HAPE - with immediate
  descent, patients improve
• Delay of descent can kill a person

DOWN
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High-altitude cerebral edema (HACE)

• Most severe form of acute high-altitude illness
• Brain swells function ceases
• The progression from mild AMS to unconsciousness
  associated with HACE may be as fast as 12 hours
  but usually requires 1 to 3 days of exposure to
  high altitudes
• Delaying immediate descent may prove fatal

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Signs and symptoms of HACE

• Hallmark of HACE - change in ability to think
• Ataxia - loss of coordination while walking
• Headache
• Altered consciousness
• Confusion
• Hallucinations
• Drowsiness
• Stupor
• Coma

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Emergency care of HACE

• Management of HACE must be prompt because the
  syndrome rapidly progresses to stupor, coma, and
  death without treatment
• Symptoms will present well before arrival back to
  Illinois
• Emergency care is focused on airway, ventilatory,
  and circulatory support and descent to a lower
  altitude

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Additional Resources For Further Information

• DAN - Divers alert network - 919-684-8111
• www.diversalertnetwork.org
• www.emedicinehealth.com
• NIEMSCA contribution for packet by
• Swedish American Hospital
• Additional review and comment by
• Sharon Hopkins, RN, BSN