Blast injuries

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Blast injuries

  1. 1. Explosives, IED’s and Blast Injuries Dale Carrison, DO, MS, FACEP, FACOEP Professor/Chairman Emergency Medicine University Medical Center University of Nevada School of Medicine
  2. 2. Bombings  First terrorist bombing in Belgium 1585  6,000Kg gunpowder used to destroy a bridge.  > 1,000 fatalities, many with no external evidence of injury.
  3. 3. Bombings  70% of all terrorists incidents are conventional.  10,000 terrorists explosions from 1990-1995.  Goal is to induce panic and apprehension.
  4. 4. Explosion  Rapid chemical conversion of a solid or liquid into a gas with resultant energy release.
  5. 5. Explosives  Propellants (e.g., gunpowder) release energy relatively slowly.  High explosives (e.g., TNT, PETN, C-4) almost instantaneous transformation of the physical space occupied by the original material within a few microseconds. Therefore, under extremely high pressure.
  6. 6. 5 Billion Pounds Produced Each Year in U.S. Explosive matter Explosives Chemicals for non- explosive purpose High explosives(HE) Propellants(LE) Pyrotechnic (LE) °1 °2 Military- grade Industrial- grade Gun Rocket Lead azide Hg fulminate Tetrazene Singles = TNT; RDX; PETN; Mixes = CB; RDX-based plastics; Torpex Gelatins; powders; permitted; ANFO; slurries, emulsions Black powder Double base; composites; liquid fuels; oxidizers Flashes, Flares Fume generators Optical/acoustic signals, fireworks Fertilizer grade ammonium nitrate Chlorates as weed killers Gas generating for foam plastics Organic peroxides as catalysts NTG and PETN-soln for pharmaceuticals Salts of nitrated organic acids for pest- control From Explosives, R. Meyer – 5th Edition
  7. 7. Explosion  Virtual instantaneous increase in pressure can be so abrupt that high- explosive blast waves (blast wind) are also “shock waves.”  Shock waves possess a characteristic called “brisance” (shattering effect).
  8. 8. Explosion  The gas expands with an exponential increase in pressure.  It forms a sphere.  The sphere of this compressed air is called a shock wave, blast pressure head, blast wind, or blast wave.  Leading edge is called the “blast front.”
  9. 9. POLICE POLICE EFFECTS OF AN EXPLOSION
  10. 10. Explosion
  11. 11. PROCESS OF DETONATION
  12. 12. Blast Front
  13. 13. Explosion  This wave of compressed air can be measured as overpressure or direct impulse.  The magnitude of the overpressure is proportional to the amount and type of explosive used.
  14. 14. Overpressure  Overpressure is measured in pounds per square inch.  Relative power is calculated by multiplying PSI X duration in milliseconds of the impulse.
  15. 15. Overpressure  Overpressure of 58 – 80psi is 95% lethal.  7 – 8psi can shear brick walls or overturn rail cars.  5psi can rupture tympanic membranes.  0.5 – 1psi can break windows and knock people down.
  16. 16. Shock Wave  The shock wave has 3 components: – Positive phase – Negative phase – Mass air movement.
  17. 17. POLICE POLICE Dynamite Positive Phase Negative Phase After an Explosion EFFECTS OF AN EXPLOSION
  18. 18. Shock Wave  Positive phase. – Velocity and duration of the blast head.  Dependant upon: – Size/type of the explosive – Surrounding media – Distance from the detonation.
  19. 19. Shock Wave  Closed spaces magnify the effects of the direct impulse.  “Shock Wave” “bounces” off hard surfaces and is referred to as a “Reflected Impulse.”
  20. 20. Shock Wave  Shock waves all create similar rates of rise in pressures at the blast front.  The magnitude of this “positive- phase impulse” becomes the important property in the generation of the Primary Blast Injury (PBI).
  21. 21. Shock Wave  Negative phase. – Partial vacuum is created near the epicenter after outward movement of air – Consumption of oxygen by the burning process.
  22. 22. Shock Wave  The “reflected impulse” may combine with the “direct impulse” and increase injuries at a greater distance from the blast site than expected.
  23. 23. Shock Wave
  24. 24. Shock Wave  Effects are cumulative.  Example: – A blast that causes a 1% mortality when experienced once, causes a 20% mortality when experienced twice, and 100% mortality if experienced three times.
  25. 25. 1. Safety Fuse 2. Electric Blasting Cap 3. Dynamite Primary ExplosiveElectric Wires Secondary Explosive EXPLOSIVE DANGEROUS EXPLOSIVE TRAIN ELECTRIC BLASTING CAPS
  26. 26. EXPLOSIVE DANGEROUS 1. Shock Tube 2. Non-Electric Blasting Cap 3. Dynamite Primary Explosive Secondary Explosive HMX/Aluminum Powder EXPLOSIVE TRAIN Shock Wave SHOCK TUBE
  27. 27. 1. Safety Fuse 2. Non-Electric Blasting Cap Low Explosive Primary Explosive (Black Powder) EXPLOSIVE TRAIN TIME/SAFETY FUSE EXPLOSIVE DANGEROUS Shock Wave 4. ANFO Blasting Agent 3. Booster Secondary Explosive
  28. 28. 1. Safety Fuse 2. Non-Electric Blasting Cap Low Explosive Primary Explosive (Black Powder) EXPLOSIVE TRAIN TIME/SAFETY FUSE EXPLOSIVE DANGEROUS Shock Wave 4. ANFO Blasting Agent 3. Booster Secondary Explosive
  29. 29. Tactical Uses
  30. 30. Det Cord Injury
  31. 31. POLICE POLICE INJURIES Blasting Cap M-80 I.E.D. M-116 Pipe Bomb Fireworks CO2
  32. 32. Injuries  Primary blast injuries (overpressure) occur in gas-containing organ systems. – Middle ear, – Lungs, – Bowels.
  33. 33. Physical Findings
  34. 34. PBI  New research indicates that most pathophysiologic effects on the body result from the consequences of extreme pressure differentials developed at body surfaces.
  35. 35. PBI  “Blast loading”  Force results in rapid acceleration of the surface, creating a relatively high-frequency “stress wave” propagated into the underlying tissues.
  36. 36. PBI – Tympanic Membrane  Tympanic membrane ruptured from overpressure of 1 – 8 psi.  Less common is dislocation of the joints in the inner ear.  Temporary hearing loss very common.  Structural damage to the organ of Corti can cause permanent hearing loss.
  37. 37. PBI – Tympanic Membrane  Studies show no correlation between ruptured TM and Blast Lung.  TM’s generally heal without complications
  38. 38. PBI - Lung  Pulmonary contusion – Worse on side of approach of blast waves in open air. – Bilateral and diffuse when victim is located in confined space.  Degree of pulmonary pathology is proportional to the velocity of chest wall displacement.
  39. 39. Blast Lung  PBI to lung is referred to as blast lung.  Greater incidence in confined spaces  Major cause of death in PBI’s  Alveolar membranes torn  Minimal to massive hemorrhage with hemothorax or air emboli
  40. 40. Blast Lung  Diagnosis made clinically  Confirmed by CXR showing a butterfly appearance with or without pneumothorax  Similar to Pulmonary Contusion or ARDS  Respiratory distress with hypoxemia greatest in the first 72 hours.
  41. 41. Blast Lung  Treatment similar to Pulmonary Contusion.  Studies have shown no long term effects  Generally normal after 1 year
  42. 42. Degree of Injuries - Pulmonary
  43. 43. PBI - Hypotension  Bradycardia and hypotension without hemorrhage. – Blast loads directly at the chest cause a unique vagal nerve-mediated form of cardiogenic shock without compensatory vasoconstriction. – Occurs within seconds and resolves over 1 – 2 hours.
  44. 44. PBI – Arterial Air Embolus (AAE)  Hemopneumothoraces, traumatic emphysema, and alveolovenous fistulas from stress-induced tears of air-tissue interfaces.  Lead directly to bronchopleural fistulas or Arterial Air Embolus (AAE).
  45. 45. PBI - AAE  AAE to the brain or head may be the most common cause of rapid death caused solely by PBI in immediate survivors.  May be precipitated by positive- pressure ventilation (PPV).  Often occurs at the moment of PPV.
  46. 46. PBI - Abdomen  Injuries occur in similar manner and at similar overpressures to the lungs.  Hemorrhages, from petechiae to large hematomas are the dominant form of pathology.  Colon most common site of hemorrhage and/or perforation.
  47. 47. PBI - Abdomen  Tension pneumoperitonem  Mesenteric, retrop eritoneal, and scrotal hemorrhages.  Usually no significant compression of solid organs.
  48. 48. Pathology
  49. 49. Injuries - Penetrating  Secondary blast injuries – Injuries from devices that contain foreign bodies: • Nails • Rivets • Ball bearings • Nuts and bolts, • Etc.
  50. 50. Secondary Missiles
  51. 51. Injuries – Penetrating
  52. 52. Injuries - Penetrating  Medically, usually no different than other penetrating injuries seen.  Complicated by the PBI’s.  Bone and tissue from suicide bombers may be secondary missiles. – Aids, hepatitis, etc.
  53. 53. Injuries - Penetrating  Secondary missiles created by container fragments or added missiles can have velocities of up to 1,500m/sec.  Rapid deceleration seconday to poor ballistic properties.
  54. 54. Injuries  Tertiary injuries – Blunt trauma. – Physically thrown through the air and strike or impale themselves on objects. – Collapsing structures. – Other objects propelled through the air striking the victim.
  55. 55. Tertiary Injuries  Severe head injury is a leading cause of death in victims of blasts.  Subdural and subarachnoid hemorrhages are the most common findings in fatalities.
  56. 56. Injuries  Thermal injuries  Primary or secondary incendiary. – Inhalation – Dermal
  57. 57. Thermal Burns – Few victims admitted to burn centers – Little skin grafting needed
  58. 58. Thermal Burns Flash Burns Large body surface area Shallow depth
  59. 59. EMS Scene  Contact incident commander to ensure that the area is safe to enter.  Beware of #2 or secondary explosion directed at personnel responding to the first incident.
  60. 60. EMS Scene  Recent studies suggest the PBI victims do poorly when strenuous physical activity follows significant blast loading. – Reduce activity of potential blast- exposed individuals. – Provide history of activity to ED personnel receiving patient.
  61. 61.  Post Mortem Care - Mass fatality event –Identification & notification – Family Assistance Center needed at scene!
  62. 62. Suicide Bombs  Explosives worn on belt or vest  Significant Shrapnel  Arms raised to maximize damage
  63. 63. Suicide Bombers  Why Suicide?  Prevention is difficult to impossible ! – NO SECURITY SYSTEM IS IMPENETRABLE IF THE BOMBER HAS A SUICIDAL INTENT  Terrorists can change targets at the last minute – Crude guided missile  Suicide Bombers = only 0.6% of all attacks . . . . . . but 66% of all fatalities!
  64. 64. Suicide Bombers  With explosive device strapped to body they sustain massive injuries.  Frequently lose their heads, secondary to the primary explosion.
  65. 65. Suicide Bombers  They sustain massive bodily injuries because of being at ground zero. Remains of first terrorist in yard Remains of third terrorist - (probably blew up with dog)
  66. 66. Suicide Bombers  Devices designed for maximum explosive value and fragmentation.
  67. 67. Suicide Bombers  Easily concealable and maximum secondary missile effect.
  68. 68. Improvised Explosive Device: IED
  69. 69. IED’s  Explosive material  Shrapnel  Common package Women’s clinic Otherside nightclub
  70. 70. Package Bombs Light enough to carry easily Common enough to blend in Centennial park
  71. 71. POWER SOURCE – 9-V Firing switch in comparison to similar switch
  72. 72. RESIDUE OF SUITCASE SUITCASE FRAME RIGHT SHOE OF THE BOMBER
  73. 73. RESIDUE OF A LEATHER OBJECT NYLON CLOTH STRIPS
  74. 74. CARDBOARD GLUED TO BULB HOUSE BULB HOUSE WHICH HOUSED THE INITIATOR
  75. 75. POWER SOURCE – 9-V FIRING SWICH. SIMILAR SWICH. ELECTRIC WIRES.
  76. 76. RESIDUE OF DETONATOR SIMILAR DETONATOR
  77. 77. RESIDUE OF MOBILE PHO COMPERISSON OF PIECES FOUND AT THE SC WITH A SIMILAR MOBILE PHONE
  78. 78. GENERAL VIEW – INSIDE OF THE CAR DRIVER'S SEAT FRAME HEAD SUPPORT
  79. 79. Suicide Bombers Massive Destruction
  80. 80. Suicide Bombers Massive Destruction
  81. 81. Suicide Bombers  Car bombing with early detonation.
  82. 82. PSYCHOLOGICAL TRAUMA
  83. 83. PSYCHOLOGICAL TRAUMA
  84. 84. Conclusion  Basic Understanding of Explosive and Explosive Devices  Awareness of Explosive Injuries  Awareness of Suicide Bombers and IED’s  Awareness of Presence of Evidence
  85. 85. Explosives and Blast Injuries QUESTIONS

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