Explosions and Blast Injuries

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Explosions and Blast Injuries
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Acknowledgements

• South Carolina Area Health Education Consortium
  (AHEC)
• Funded by the Health Resources and Services
  Administration.
• Grant number 1T01HP01418-01-00
• P.I. David Garr, MD, Executive Director AHEC
• BT Project Director Beth Kennedy, Associate
  Program Director AHEC
• Core Team
• BT Co-director Ralph Shealy, MD
• BT Project Manager Deborah Stier Carson, PharmD
• BT CME Director William Simpson, MD
• IT Coordinator Liz Riccardone, MHS
• Web Master Mary Mauldin, PhD
• P.R Coordinator Nicole Brundage, MHA
• Evaluation Specialist Yvonne Michel, PhD
• Financial Director Donald Tyner, MBA

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Acknowledgment

• This material has been prepared for SC AHEC
  Bioterrorism Training Networkby
• Ralph M. Shealy, M.D., FACEPCo-Director of SC
  AHEC Bioterrorism Training Network
• Medical Director for Operations, Charleston
  County EMS
• Medical Director, Charleston County Rescue Squad

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Objectives

• Outline what terrorist attacks are most common
  and most likely to occur again.
• Describe the different types of injuries that
  occur in an explosion.
• Describe the mechanism of blast injury.
• Describe physical findings used to triage
  multiple victims of an explosion.
• Describe the attributes of an explosive device.
• Describe what to do if you encounter a suspicious
  object.

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Explosions

• A primary cause of wartime morbidity and
  mortality.
• Occur in mining, grain storage, and many other
  industrial settings.
• A common cause of fire-related injury.
• A high risk in the manufacture of illicit drugs.
• A vehicle of social protest.

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Explosion as Weapon of Terror

• Marine Barracks, Beirut October 23, 1983
• Pan Am 103, December 21, 1988
• World Trade CenterFebruary 26, 1993
• Oklahoma CityApril 19, 1995

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Prevalence of the Bomb

• Half of all terrorist attacks worldwide have been
  bombings.
• 86 of all terrorist incidents in the U.S. have
  been bombings.

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A Terrorism Attack is a Community Disaster
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Disaster

• Imminently threatens public health and safety.
• Cannot be handled using routine measures.
• Disrupts essential services.
• A community health emergency!

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• Whether a building collapses as the result of an
  explosion or as the result of an earthquake, its
  consequences and management are much the same.

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Types of Terrorism

• Small arms
• Explosive
• Incendiary
• Chemical
• Biological
• Radiation

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Disasters

• Man-made
• Unintentional
• Structural Collapse
• Transportation Accident
• Hazardous Material Spill
• Industrial Accident
• Explosion
• Intentional
• Crime
• Civil disturbance
• War
• Terrorism
• Small arms
• Explosive
• Incendiary
• Chemical
• Biological
• Radiation

• Natural
• Weather
• Flood
• Hurricane
• Tornado
• Winter storm
• Geophysical
• Earthquake
• Tidal wave
• Volcanic Eruptions

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Brief Primer on Explosives

• Energetic materials
• Can undergo an exothermal chemical reaction,
  rapidly releasing a large amount of energy
• Can occur in fractions of a second
• Solids and liquids transformed into superheated
  gases almost instantaneously.

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Energetic Materials

• Pyrotechnics
• Propellants
• Explosives

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Classification of Explosives

• Classified by
• The stimuli to which they respond
• The degree of response once initiated.

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Insults Initiate Explosions

• Heat
• Friction
• Impact
• Electrostatic discharge
• Shock

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High and Low Explosives

• High explosives detonate at speeds greater than
  3,000 feet per second.
• Low explosives detonate at speeds less than 3,000
  feet per second.
• The category of the explosive dictates safety
  precautions

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Low Explosives

• Designed to burn or deflagrate.
• Black powder.
• Smokeless powder.

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High Explosives

• Detonate rather than deflagrate.
• Initiated by the shock of a detonator.
• Typically will not detonate by spark or flame.
• TNT, dynamite, nitroglycerine, and C-4 are high
  explosives.

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High Explosives

• Ammonium Nitrate and Fuel Oil (ANFO)
• Favored homemade explosive
• Used in Oklahoma City
• Common in car and truck bombs
• Has legitimate uses

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The Improvised Explosive Device

• Are made in an improvised manner incorporating
  explosives or destructive, lethal, noxious,
  pyrotechnic or incendiary chemicals.
• Intended to destroy, disfigure, distract, or
  harass.
• Placed or delivered to a target.

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Components of an IED

• Power Supply
• Initiator
• Explosive
• Switch
• Packaging

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Fusing of Improvised Explosive Devices

• Electronic
• Mechanical
• Sensors which respond to a myriad of stimuli
• Light
• Sound
• Motion
• Pressure
• Vibration
• Temperature

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Letter Bombs

• Marked Personal
• Mailed from a foreign country
• Excess postage
• Addressed to a person by title only
• Badly typed or written
• Misspelled words
• Rigid or bulky
• No return address.

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Vehicle Bombs

• Vehicles make excellent delivery system for
  homemade explosives.
• A small pick-up will hold more than 2.5 times the
  explosives that were used to bomb the World Trade
  Center in 1993.
• A standard pick-up will hold the amount of
  explosives used to bomb the Federal Building in
  Oklahoma City.

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Brief Case Bomb currently used by suicide
bombers in Israel
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Concealed Bomb currently used by suicide bombers
in Israel
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Concealed Bomb
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Mechanics of an Explosion

• Explosives are converted to massive volumes of
  gas when detonated.
• Pressure wave radiates outward, producing
  overpressurization.
• Rapidly expanding gases result in blast wind.
• Blast wind can result in atomization of tissue.

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The Explosion Site and Structural Considerations

• Fire and blast damage create structural
  instability.
• Assessment of stability is a job for structural
  engineers.
• Unstable elements must be shored up or pulled
  down for the safety of rescuers.
• No one should enter an unstable structure to
  recovery bodies.

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Explosion Site as HazMat Incident

• Stored hazardous materials released.
• Blood and body fluids.
• Decomposition of remains.
• Personal Protective Equipment essential.

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Explosion Site as Crime Scene

• All explosions will be investigated.
• Preserve evidence!
• Disturb site only as necessary to rescue the
  living.
• Do not disturb fatalities.
• Be wary of secondary devices.

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Types of Injuries with Explosions

• Type I Blast wave pressure injuries
• Type II Flying debris strikes victim
• Type III Victim thrown into stationary object
• Type IV Thermal burns, radiation, inhalation,
  crush injuries

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Type I Injuries

• Overpressure injuries are not familiar to many
  trauma care providers.
• Solid, non-compressible organs vibrate during
  overpressurization.
• Gas-filled organs are compressible. Rapid
  changes in pressure results in distortion and
  tearing.

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Mechanisms of Type I Injuries

• Spalling
• Implosion
• Differential acceleration and deceleration.

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Organs Commonly Injured

• Ears
• Lungs
• Central Nervous System
• Gastrointestinal Tract

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Ear Manifestations

• Hearing loss
• Rupture of tympanic membrane
• Disruption of ossicles
• Perilymphatic fistula

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Triage Pearl

• A patient with intact tympanic membranes is
  unlikely to have any other significant
  overpressure injury!
• Use the otoscope to triage blast victims.

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Pulmonary Overpressure Syndrome

• Most life threatening pressure wave injury.
• Alveolar rupture.
• Interstitial and intra-alveolar hemorrhage and
  edema.
• Lacerations of lung and pleura.
• Alveolar-venous fistulae.

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Pulmonary Overpressure Syndrome

• Non-cardiogenic pulmonary edema
• Subcutaneous and mediastinal emphysema
• Simple pneumothorax or tension pneumothorax
• Arterial air embolism.

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CNS Blast Wave Injuries

• Blast wave concussive effects.
• Brain tissue injury with bleeding and swelling.
• Embolic stroke secondary to arterial air embolism.

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Gastrointestinal Overpressure

• GI blast injury is more common in explosions on
  or under the water.
• Results in damage to bowel wall, including
  perforated viscus.
• May be detected as occult or gross blood in the
  stool.
• If perforation occurs, the typical findings or
  perforated viscus are expected.

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WARNING!

• Potentially fatal primary blast injuries may not
  be initially obvious.
• Some blast victims are dead men walking.
• Signs and symptoms evolve over hours.
• Any victim with ruptured ear drums needs
  observation for twelve hours.

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Management

• Blast victims should be managed as any trauma
  victim, with special attention to the respiratory
  system.
• Positive pressure ventilation may be necessary
  because of hemorrhage or fluid in the lungs, but
  risk or complications is high.
• Arterial gas emboli benefit from hyperbaric
  oxygen therapy.

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Trauma

• Flying debris and violent impacts cause blunt and
  penetrating trauma
• Crush injuries and burns are similar to the same
  injuries caused by other mechanisms.
• Trauma not due to overpressure are very familiar
  to trauma care providers.

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Situations

• Bomb threats
• Most made by phone
• Most are hoaxes
• Occur in clusters
• Often cause evacuation of workplace or school

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Bomb Threats

• Information to get from caller
• Location of bomb(s)
• Type/size of bomb(s)
• Time of Detonation
• Detonation timed, on command, or other

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Bomb Threats

• Information from threat recipient
• Time and duration of call
• Background noises during call
• Attributes of callers voice

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Bomb Threats

• Evacuation Procedures
• Time until detonation
• Evacuation distance
• Shielding

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Situations

• Suspicious Items
• Found in potential bombing target, such as an
  airport
• Often are false alarms
• Real threats often go unnoticed

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Conclusions

• Health professionals may encounter both
  accidental and intentional explosions.
• Blast overpressure injuries are unfamiliar to
  most providers and signs and symptoms must be
  intentionally sought.
• The appearance of bombs varies widely and are
  best recognized as something out of place.
• Every healthcare organization needs to have plans
  for responding to bomb threats and suspicious
  objects.

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Acknowledgements

• This presentations borrows heavily from
• Incident Response to Terrorist Bombings,
  produced by the New Mexico Institute of Mining
  and Technology Energetic Materials Research and
  Testing Center.
• Emergency Medicine, Fourth Edition, produced by
  the American College of Emergency Physicians and
  edited by Judith Tintinalli, M.D.

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