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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
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.
Bombings
70% of all terrorists incidents are conventional.
10,000 terrorists explosions from 1990-1995.
Goal is to induce panic and apprehension.
Explosion
Rapid chemical conversion of a solid or liquid into a gas with resultant energy release.
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.
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 azideHg fulminateTetrazene
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, FlaresFume 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
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).
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.”
POLICEPOLICE
EFFECTS OF AN EXPLOSIONEFFECTS OF AN EXPLOSION
Explosion
PROCESS OF DETONATION
Blast Front
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.
Overpressure
Overpressure is measured in pounds per square inch.
Relative power is calculated by multiplying PSI X duration in milliseconds of the impulse.
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.
Shock Wave
The shock wave has 3 components:– Positive phase– Negative phase– Mass air movement.
POLICEPOLICE
Dynamite Dynamite
Positive PhasePositive Phase
Negative PhaseNegative PhaseAfter an ExplosionAfter an Explosion
EFFECTS OF AN EXPLOSION
Shock Wave
Positive phase.– Velocity and duration of the blast head.
Dependant upon:– Size/type of the explosive– Surrounding media– Distance from the detonation.
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.”
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).
Shock Wave
Negative phase.– Partial vacuum is created near the
epicenter after outward movement of air– Consumption of oxygen by the burning
process.
Shock Wave
The “reflected impulse” may combine with the “direct impulse” and increase injuries at a greater distance from the blast site than expected.
Shock Wave
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.
1. Safety Fuse
2. Electric Blasting Cap
3. Dynamite
Primary ExplosiveElectric Wires
Secondary Explosive
EXPLOSIVE DANGEROUS
EXPLOSIVE TRAINELECTRIC BLASTING CAPS
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
1. Safety Fuse
2. Non-Electric Blasting Cap
Low Explosive Primary Explosive
(Black Powder)
EXPLOSIVE TRAINTIME/SAFETY FUSE
EXPLOSIVE DANGEROUS Shock Wave
4. ANFO Blasting Agent
3. Booster
Secondary Explosive
1. Safety Fuse
2. Non-Electric Blasting Cap
Low Explosive Primary Explosive
(Black Powder)
EXPLOSIVE TRAINTIME/SAFETY FUSE
EXPLOSIVE DANGEROUS Shock Wave
4. ANFO Blasting Agent
3. Booster
Secondary Explosive
Tactical Uses
Det Cord Injury
POLICEPOLICE
INJURIES
Blasting Cap
M-80
I.E.D.M-116 Pipe BombFireworksCO2
Injuries
Primary blast injuries (overpressure) occur in gas-containing organ systems.– Middle ear, – Lungs,– Bowels.
Physical Findings
PBI
New research indicates that most pathophysiologic effects on the body result from the consequences of extreme pressure differentials developed at body surfaces.
PBI
“Blast loading” Force results in rapid acceleration of
the surface, creating a relatively high-frequency “stress wave” propagated into the underlying tissues.
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.
PBI – Tympanic Membrane
Studies show no correlation between ruptured TM and Blast Lung.
TM’s generally heal without complications
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.
Blast Lung
PBI to lung is referred to as blast lung.
Greater incidence in confined spacesMajor cause of death in PBI’sAlveolar membranes tornMinimal to massive hemorrhage with
hemothorax or air emboli
Blast Lung
Diagnosis made clinicallyConfirmed 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.
Blast Lung
Treatment similar to Pulmonary Contusion.
Studies have shown no long term effects
Generally normal after 1 year
Degree of Injuries - Pulmonary
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.
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).
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.
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.
PBI - Abdomen
Tension pneumoperitonem
Mesenteric, retroperitoneal, and scrotal hemorrhages.
Usually no significant compression of solid organs.
Pathology
Injuries - Penetrating
Secondary blast injuries– Injuries from
devices that contain foreign bodies:• Nails• Rivets • Ball bearings• Nuts and bolts,• Etc.
Secondary Missiles
Injuries – Penetrating
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.
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.
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.
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.
Injuries
Thermal injuries Primary or
secondary incendiary. – Inhalation– Dermal
Thermal Burns– Few victims admitted to burn centers– Little skin grafting needed
Thermal BurnsFlash Burns
Large body surface area
Shallow depth
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.
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.
Post Mortem Care - Mass fatality event– Identification & notification– Family Assistance Center needed at scene!
Suicide Bombs Explosives worn on
belt or vest Significant Shrapnel Arms raised to
maximize damage
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!
Suicide Bombers
With explosive device strapped to body they sustain massive injuries.
Frequently lose their heads, secondary to the primary explosion.
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)
Suicide Bombers
Devices designed for maximum explosive value and fragmentation.
Suicide Bombers
Easily concealable and maximum secondary missile effect.
Improvised Explosive Device: IED
IED’s
Explosive material Shrapnel Common package
Women’s clinic
Otherside nightclub
Package BombsLight enough to carry easily
Common enough to blend in
Centennial park
POWER SOURCE – 9-V BATTERYS.
Firing switch in comparison
to similar switch
RESIDUE OF SUITCASE SUITCASE FRAME
RIGHT SHOEOF THE BOMBER
RESIDUE OF A LEATHER OBJECT
NYLON CLOTH STRIPS
CARDBOARD GLUED TO BULB HOUSE
BULB HOUSE WHICH HOUSED THE INITIATOR
POWER SOURCE – 9-V BATTERY.
FIRING SWICH.
SIMILAR SWICH.
ELECTRIC WIRES.
RESIDUE OF DETONATOR
SIMILARDETONATOR
RESIDUE OF MOBILE PHONE
COMPERISSON OF PIECES FOUND AT THE SCENEWITH A SIMILAR MOBILE PHONE
GENERAL VIEW – INSIDE OF THE CAR
DRIVER'S SEATFRAME
HEAD SUPPORT
Suicide Bombers Massive Destruction
Suicide Bombers Massive Destruction
Suicide Bombers
Car bombing with early detonation.
PSYCHOLOGICAL TRAUMA
PSYCHOLOGICAL TRAUMA
Conclusion
Basic Understanding of Explosive and Explosive Devices
Awareness of Explosive Injuries Awareness of Suicide Bombers and
IED’sAwareness of Presence of Evidence
Explosives and Blast Injuries
QUESTIONS