Transcript: #StandardsGoals for 2024: What’s new for BISAC - Tech Forum 2024
Blast injuries
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. 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. Bombings
70% of all terrorists incidents are
conventional.
10,000 terrorists explosions from
1990-1995.
Goal is to induce panic and
apprehension.
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. 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. 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. 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.”
14. 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.
15. Overpressure
Overpressure is measured in pounds
per square inch.
Relative power is calculated by
multiplying PSI X duration in
milliseconds of the impulse.
16. 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.
17. Shock Wave
The shock wave has 3 components:
– Positive phase
– Negative phase
– Mass air movement.
19. Shock Wave
Positive phase.
– Velocity and duration of the blast head.
Dependant upon:
– Size/type of the explosive
– Surrounding media
– Distance from the detonation.
20. 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.”
21. 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).
22. Shock Wave
Negative phase.
– Partial vacuum is created near the
epicenter after outward movement of air
– Consumption of oxygen by the burning
process.
23. Shock Wave
The “reflected impulse” may
combine with the “direct impulse”
and increase injuries at a greater
distance from the blast site than
expected.
25. 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.
26. 1. Safety Fuse
2. Electric
Blasting Cap
3. Dynamite
Primary ExplosiveElectric Wires
Secondary Explosive
EXPLOSIVE DANGEROUS
EXPLOSIVE TRAIN
ELECTRIC BLASTING CAPS
39. PBI
New research indicates that most
pathophysiologic effects on the body
result from the consequences of
extreme pressure differentials
developed at body surfaces.
40. PBI
“Blast loading”
Force results in rapid acceleration of
the surface, creating a relatively
high-frequency “stress wave”
propagated into the underlying
tissues.
41. 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.
42. PBI – Tympanic Membrane
Studies show no correlation between
ruptured TM and Blast Lung.
TM’s generally heal without
complications
43. 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.
44. 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
45. 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.
46. Blast Lung
Treatment similar to Pulmonary
Contusion.
Studies have shown no long term
effects
Generally normal after 1 year
48. 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.
49. 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).
50. 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.
51. 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.
52. PBI - Abdomen
Tension
pneumoperitonem
Mesenteric, retrop
eritoneal, and
scrotal
hemorrhages.
Usually no
significant
compression of
solid organs.
58. 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.
59. 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.
60. 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.
61. 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.
65. 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.
66. 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.
67. Post Mortem Care - Mass fatality event
–Identification & notification
– Family Assistance Center needed at scene!
69. 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!
70. Suicide Bombers
With explosive
device strapped to
body they sustain
massive injuries.
Frequently lose
their heads,
secondary to the
primary explosion.
71. 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)
90. Conclusion
Basic Understanding of Explosive
and Explosive Devices
Awareness of Explosive Injuries
Awareness of Suicide Bombers and
IED’s
Awareness of Presence of Evidence