Topics in Emergency Medicine: Environmental Emergencies

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Topics in Emergency Medicine Environmental
Emergencies

• Michael S. Czekajlo, MD, PhD
• Virginia Commonwealth University
• Richmond, Virginia

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Virginia Commonwealth University Health System
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Objectives

• Discuss assessment and grading of burns
• Discuss treatment of burns
• Learn the Parkland Formula
• Discuss pathophysiology of cold injuries
• Learn Management of cold injuries
• Discuss pathophysiology of electrical injuries
• Discuss treatment of electrical injuries
• Discuss etiolgy of high altitude sickness and its
  managment

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Skin

• Thermal regulation and prevention of fluid loss
  by evaporation
• Hermetic barrier against infection
• Sensory receptors that provide information about
  environment

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First-degree burn

• The skin is usually red, with swelling, and pain
  sometimes is present.

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Superficial (first-degree) burns involve only the
epidermis.

• Tissue blanches with pressure.
• Tissue is erythematous.
• Tissue damage is minimal.
• Edema may be present generally blisters do not
  form.
• Sunburn is a classic example of this type of burn
• These wounds are red, dry, painful, and generally
  heal in 3-6 days without scarring

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Partial-thickness burns (second-degree)

• These wounds are red, wet, and painful
• Epidermis and portions of the dermis are
  involved.
• Blisters usually form either very quickly or
  within 24 hours.
• Superficial and deep partial-thickness can be
  difficult to differentiate at the bedside.
• Adnexal structures (eg, sweat glands, hair
  follicles) involved, but enough of these
  structures are preserved for function, and the
  epithelium lining them can proliferate and allow
  for regrowth of skin.
• If deep second-degree burns are not cared for
  properly, edema, which accompanies the injury,
  and decreased blood flow in the tissue can result
  in conversion to full-thickness burn.

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2nd Degree Burn
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Full-thickness (third-degree) burns

• Involve all layers of the skin
• Causes permanent tissue damage
• Fat, muscle, tendons, nerves, and bone may be
  affected.
• Areas may be charred black or appear dry and
  white.

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Full Thickness, 3rd Degree Burn
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Trauma and Inhalation Injury

• Burn victims rarely immediately die due to burn
  injury.
• Immediate death is the result of coexisting
  trauma or airway compromise.

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Rule of 9s
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Pediatric Table
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Treatment

• Don't use ice. Putting ice directly on a burn can
  cause a burn victim's body to become too cold and
  cause further damage to the wound.
• Don't apply butter or ointments to the burn. This
  could cause infection.
• Don't break blisters.

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Treatment

• Don't remove burned clothing. However, do make
  sure the victim is no longer in contact with
  smoldering materials or exposed to smoke or heat.
  
• Don't immerse large severe burns in cold water.
  Doing so could cause a drop in body temperature
  (hypothermia) and deterioration of blood pressure
  and circulation (shock).
• Check for signs of circulation (breathing,
  coughing or movement). If there is no breathing
  or other sign of circulation, begin CPR.
• Elevate the burned body part or parts. Raise
  above heart level, when possible.
• Cover the area of the burn. Use a cool, moist,
  sterile bandage clean, moist cloth or moist
  towels.

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Treatment

• Perform a rapid primary survey to assess the
  status of the patient's airway, breathing, and
  circulation. Immediately correct any problems
  found.
• Remove constricting clothing and jewelry to
  prevent these items from exerting a
  tourniquet-like effect following the development
  of burn edema. 
• During airway assessment, give careful attention
  to signs of inhalation injury carbonaceous
  sputum, singed facial or nasal hairs, facial
  burns, oropharyngeal edema, changes in the voice,
  or altered mental status
• Secure the airway by endotracheal intubation,
  as necessary.
• Deliver high-flow supplemental oxygen
• Fluid administration should begin immediately
  with warmed fluid if possible

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Parkland formula (2-4 ml of crystalloid) X (
BSA burn) X (body wt in kg)

• Example A man who weighs 70 kg and has a 30 BSA
  burn would require (30) X (70 kg) X (4 ml) 8400
  ml in the first 24 hours.
• 1/2 of the calculated fluid requirement is
  administered in the first 8 hours
• ½ remaining is given over 16 hours.
• 525 ml/h for the first 8 hours
• 262.5 ml/h for the remaining 16 hours.

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Cold Injuries
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Who gets cold injuries?
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Pathophysiology

• Cold exposure leads to ice crystal formation,
  cellular dehydration, protein denaturation,
  inhibition of DNA synthesis, abnormal cell wall
  permeability with resultant osmotic changes,
  damage to capillaries, and pH changes. Rewarming
  causes cell swelling, erythrocyte and platelet
  aggregation, endothelial cell damage, thrombosis,
  tissue edema, increased compartment space
  pressure, bleb formation, localized ischemia, and
  tissue death.

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Degree of Injury

• First-degree injury - Erythema, edema, waxy
  appearance, hard white plaques, and sensory
  deficit
• Second-degree injury - Erythema, edema, and
  formation of blisters filled with clear or milky
  fluid and which are high in thromboxane (These
  blisters form within 24 hours of injury.)
• Third-degree injury - Presence of blood-filled
  blisters, which progress to a black eschar over a
  matter of weeks
• Fourth-degree injury - Full-thickness damage
  affecting muscles, tendons, and bone, with
  resultant tissue loss

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Cold Injury
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Treatment

• Address life-threatening conditions first.
• Replace wet clothing with dry, soft clothing to
  minimize further heat loss.
• Initiate rewarming of affected area as soon as
  possible. Do not attempt rewarming if a danger of
  refreezing is present. Avoid rubbing the affected
  area with warm hands or snow, as this can cause
  further injury. If the affected body part is an
  extremity, wrap it in a blanket for mechanical
  protection during transport.
• Avoid alcohol or sedatives, which can enhance
  heat loss and impair shivering.
• It is better to walk with frozen feet to shelter
  than to attempt rewarming at the scene however,
  walking on frostbitten feet may cause tissue
  chipping or fracture.

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Hypothermia
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Pathophysiology

• Hypothermia affects virtually all organ systems.
  Perhaps the most significant effects are seen in
  the cardiovascular system and the CNS.
• Bradycardia (not vagally mediated),
• Decreased Mean arterial pressure
• Decreased cardiac output
• Atrial and ventricular arrhythmias
• Asystole and ventricular fibrillation have been
  noted to begin spontaneously at core temperatures
  below 25-28C

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Definitions

• mild hypothermia (32-35C body temperature)
• moderate hypothermia (28-32C body temperature)
  mortality of 21
• severe hypothermia (core temperature below 28C).
  mortality from moderate or severe hypothermia
  approaches 40.

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Mild Hypothermia

• Between 34C and 35C, most people shiver
  vigorously, usually in all extremities.
• Below 34C, a patient may develop altered
  judgment, amnesia, and dysarthria. Respiratory
  rate may increase.
• At approximately 33C, ataxia and apathy may be
  seen. Patients generally are stable
  hemodynamically and able to compensate for the
  symptoms.
• lt 33C the following may also be observed
  hyperventilation, tachypnea, tachycardia, and
  cold diuresis as renal concentrating ability is
  compromised.

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Moderate hypothermia (28-32C)

• Oxygen consumption decreases, and the CNS
  depresses further hypoventilation, hyporeflexia,
  decreased renal flow, and paradoxical undressing
  may be noted.
• Most patients with temperatures of 32C or lower
  present in stupor.
• As the core reaches temperatures of 31C or
  below, the body loses its ability to generate
  heat by shivering.
• At 30C, patients develop a higher risk for
  arrhythmias. Atrial fibrillation and other atrial
  and ventricular rhythms become more likely. The
  pulse continues to slow progressively, and
  cardiac output is reduced. J wave may be seen on
  ECG in moderate hypothermia.
• Between 28C and 30C, pupils may become markedly
  dilated and minimally responsive to light, a
  condition that can mimic brain death.

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Severe hypothermia (lt28C)

• At 28C, the body becomes markedly susceptible to
  ventricular fibrillation and further depression
  of myocardial contractility.
• Below 27C, 83 of patients are comatose.
• Pulmonary edema, oliguria, coma, hypotension,
  rigidity, apnea, pulselessness, areflexia,
  unresponsiveness, fixed pupils, and decreased or
  absent activity on EEG are all seen.

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Treatment

• ?

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Heat Stroke

• Heatstroke is the most severe form of the
  heat-related illnesses and is defined as a body
  temperature higher than 41.1C (106F) associated
  with neurologic dysfunction.

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Pathophysiology

• Excessive heat denatures proteins, destabilizes
  phospholipids and lipoproteins, and liquefies
  membrane lipids, leading to cardiovascular
  collapse, multiorgan failure, and, ultimately,
  death.

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Heat Related Emergencies
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Treatment
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Treatment

• Ice-water immersion
• Evaporative techniques
• Gastric lavage
• Cold IVF
• Bypass
• No aspirin or paracetamol

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Electric Shock
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Pathophysiology

• Electrical energy causing direct tissue damage,
  altering cell membrane resting potential, and
  eliciting muscle tetany.
• Conversion of electrical energy into thermal
  energy, causing massive tissue destruction and
  coagulative necrosis.
• Mechanical injury with direct trauma resulting
  from falls or violent muscle contraction.

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Electrical Injury
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How would you treat an electrical injury?
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High Altitude Sickness
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High Altitude Sickness

• The high altitude environment generally refers to
  elevations over 1500 m (4900 ft).
• Moderate altitude, 2000-3500 m (6600-11,500 ft),
  includes the elevation of many ski resorts.
  Although arterial oxygen saturation is well
  maintained at these altitudes, low PO2 results in
  mild tissue hypoxia, and altitude illness is
  common.
• Very high altitude refers to elevations of
  3500-5500 m (11,500-18,000 ft).

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High Altitude sickness

• Altitude illness refers to a group of syndromes
  that result from hypoxia. Acute mountain sickness
  (AMS) and high-altitude cerebral edema (HACE) are
  manifestations of the brain pathophysiology,
  while high-altitude pulmonary edema (HAPE) is
  that of the lung

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Treatment

• Return to lower atmosphere
• Steroids (dexamethasone)
• Hyperbaric chamber

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Questions ?
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