Blast injuries

Blast injury
BYBY
DR.SEFEEN SAIF ATTYADR.SEFEEN SAIF ATTYA
Surgery departmentSurgery department

Blast injuryBYBY
DR.SEFEEN SAIF ATTYADR.SEFEEN SAIF ATTYA
Surgery departmentSurgery department

Blast injury
 Terrorism is now a global
phenomenon.
 Both civilian, as well as military,
surgeons will be exposed to patients
injured in explosions.

Once notified of a possibleOnce notified of a possible
bombing or explosion, hospital-bombing or explosion, hospital-
based physicians should considerbased physicians should consider
immediately activating hospitalimmediately activating hospital
disaster plans, includingdisaster plans, including
preparations to care for anywherepreparations to care for anywhere
from a handful to hundreds offrom a handful to hundreds of
victims.victims.

Blast injury
 Blast injuries in civilian populations occur as aBlast injuries in civilian populations occur as a
result ofresult of
fireworks,fireworks,
household explosions, orhousehold explosions, or
industrial accidentsindustrial accidents..
 Terrorist tactics may take the form ofTerrorist tactics may take the form of
letter bombs,letter bombs,
suitcase bombs,suitcase bombs,
vehicle bombs, andvehicle bombs, and
suicide bomberssuicide bombers..

Types of Blasts
 High order explosive
• Explosion is supersonic
• Blast contains a over-pressurized wave
 A wave where the air is compressed to a point where
it can itself be dangerous
 Followed by under-pressure as the air pressure drops
before returning to normal
 Low order explosive
• Explosion is not as fast as the speed of sound
• No over-pressurization wave

BackgroundBackground
 Explosions have the capability to causeExplosions have the capability to cause
multisystem, life-threatening injuries inmultisystem, life-threatening injuries in
single or multiple victims simultaneously.single or multiple victims simultaneously.
 Explosions can produce classic injuryExplosions can produce classic injury
patterns from blunt and penetratingpatterns from blunt and penetrating
mechanisms to several organ systems, butmechanisms to several organ systems, but
they can also result in unique injurythey can also result in unique injury
patterns to specific organs including thepatterns to specific organs including the
lungs and the central nervous systemlungs and the central nervous system

 Penetrating injuries caused by gunshot wounds are most often
limited to one or two body regions. Penetrating injuries caused by
the detonation of an explosive device carried by a suicide bomber
are widespread and cover a large surface area. Each particle may
cause less damage than gunshot wound (GSW), but the multiplicity
of particles causes diffuse tissue damage.
 Survivors suffer a combination of penetrating wounds of varying
severity and location.
 The extent and severity of injury will depend on factors such as
the explosive power of the device, distance of the victim from site
of detonation, quantity and mass of shrapnel, and attack setting.

 A mass movement of air from the rapid expansion
of gases at the centre of the explosion displaces air at
supersonic speed. This results in injury patterns ranging
from traumatic amputation to total body disruption.
 When a blast pressure wave hits the body,
the force of the impact sets up a series of stress
waves that are capable of internal injury, particularly at
air–fluid interfaces. Thus, injury to the ear, lungs,
heart and, to a lesser extent, the gastrointestinal tract.

Mechanisms of injuryMechanisms of injury
following bombing attacksfollowing bombing attacks
))11((Primary blast injury (PBI)Primary blast injury (PBI) occurs as a direct effect of changes inoccurs as a direct effect of changes in
atmospheric pressure caused by the blast waveatmospheric pressure caused by the blast wave..
Injury to gas-containing organs such asInjury to gas-containing organs such as
perforation of the middle ear and BLI are most commonperforation of the middle ear and BLI are most common
))22((Secondary blast injurySecondary blast injury is caused by shrapnel and debris that are propelledis caused by shrapnel and debris that are propelled
by the blast. Compared to high-velocity firearms, shrapnel travelby the blast. Compared to high-velocity firearms, shrapnel travel
at lower velocity (800–1,000 m/sec vs. 300–400 m/sec, respectivelyat lower velocity (800–1,000 m/sec vs. 300–400 m/sec, respectively(,(,
and thus the energy each particle contains is lower. The damage each particleand thus the energy each particle contains is lower. The damage each particle
inflicts depends on its mass, distance from explosive device, and ballisticinflicts depends on its mass, distance from explosive device, and ballistic
shapeshape
))33((Tertiary blast injuryTertiary blast injury includes injury from collapsing buildings and from aincludes injury from collapsing buildings and from a
Victim’s body being displaced by expanding gasses and high winds; traumaVictim’s body being displaced by expanding gasses and high winds; trauma
then occurs from impacting objects and displacement of the victimsthen occurs from impacting objects and displacement of the victims
))44((quaternary injuries.quaternary injuries. Burns and associated injuriesBurns and associated injuries
such as inhalation of dust, smoke, and other chemicalssuch as inhalation of dust, smoke, and other chemicals

Mechanism of primary blast
injury
The size of the explosive charge determines the
velocity of the blast wave and the duration of
overpressure.
Detonation of a 50 lb charge of TNT creates an
overpressure 100–150 psi.
Primary blast injury (PBI) mostly occurs in gas-
containing organs such as the lungs, middle ear,
and bowel.
The three mechanisms which cause tissue
damage are termed implosion, spalling, andimplosion, spalling, and
acceleration–decelerationacceleration–deceleration

 implosion occurs as the shock wave travels through an organ containing pockets of
gas The pockets of gas are initially compressed by the surrounding fluid.
As the shock wave passes, these pockets of gas expand rapidly, resulting in an
internal explosion.
 Spalling occurs at the interface between media of different densities when the shock
Wave passes from a high density to a lower density substance.
In the lungs these pressure differentials tear the alveolar walls and disrupt the
alveolar/capillary interface.
The result is the formation of giant emphysematous spaces filled with blood.
 acceleration and deceleration injury occurs as a blast wave accelerates tissues
of different densities at different rates causing soft tissue destruction
Acceleration caused by the blast wave of an organ with elastic fixation such as bowel
mesentery and rapid deceleration caused by the anatomic fixation can result in organ
damage .

Expected injuries
following bombing attacks
 Victims of terrorist explosions are more severely
injured than victims of other types of trauma
 The need for abdominal, vascular, and
neurosurgical procedures is higher / The extent of
injuries is also more severe and more complex
compared with victims of
other forms of trauma.
 Effects of the blast and heat waves, and multiple
penetrating injuries, are common among victims
and
are the hallmark of such attacks.

CategoryCategory CharacteristicsCharacteristics Body Part AffectedBody Part Affected Types of InjuriesTypes of Injuries
PrimaryPrimary Results from the impact ofResults from the impact of
the over-pressurizationthe over-pressurization
wave with body surfaces. wave with body surfaces.
Gas filled structuresGas filled structures
lungs, GI tract, andlungs, GI tract, and
middle ear.middle ear.
Blast lung injuryBlast lung injury
TM ruptureTM rupture and middle earand middle ear
damage damage
Abdominal hemorrhageAbdominal hemorrhage
and perforationand perforation
ConcussionConcussion (TBI)(TBI)
SecondarySecondary Results from flying debrisResults from flying debris
and bomb fragments. and bomb fragments.
Any body part may beAny body part may be
affected.affected.
Penetrating blunt injuriesPenetrating blunt injuries
Eye penetrationEye penetration
TertiaryTertiary Results from individualsResults from individuals
being thrown by the blastbeing thrown by the blast
wind.wind.
affected.affected.
Fracture and traumaticFracture and traumatic
amputation amputation
Closed and open brainClosed and open brain
injuryinjury
Quaternary Quaternary All explosion-relatedAll explosion-related
injuries, illnesses, orinjuries, illnesses, or
diseases not due to primary,diseases not due to primary,
secondary, or tertiarysecondary, or tertiary
mechanisms. mechanisms.
affected.affected.
BurnsBurns
Crush injuriesCrush injuries
Closed and open brainClosed and open brain
injuryinjury
breathing problems frombreathing problems from
dust, smoke, or toxicdust, smoke, or toxic
fumesfumes

Overview of Explosive-Related Injuries
SystemSystem Injury or ConditionInjury or Condition
AuditoryAuditory TM rupture, ossicular disruption, cochlear damage, foreignTM rupture, ossicular disruption, cochlear damage, foreign
bodybody
Eye, Orbit, FaceEye, Orbit, Face Perforated globe, foreign body, fracturesPerforated globe, foreign body, fractures
RespiratoryRespiratory Blast lung, hemothorax, pneumothorax, pulmonaryBlast lung, hemothorax, pneumothorax, pulmonary
contusion and hemorrhage, A-V fistulas (source of aircontusion and hemorrhage, A-V fistulas (source of air
embolism),embolism),
DigestiveDigestive Bowel perforation, hemorrhage, ruptured liver or spleen,,Bowel perforation, hemorrhage, ruptured liver or spleen,,
mesenteric ischemia from air embolismmesenteric ischemia from air embolism
CirculatoryCirculatory Cardiac contusion, myocardial infarction from airCardiac contusion, myocardial infarction from air
embolism, shock,, peripheral vascular injury,embolism, shock,, peripheral vascular injury,
CNS InjuryCNS Injury Concussion, closed and open brain injury, spinal cordConcussion, closed and open brain injury, spinal cord
injury,injury,
Renal InjuryRenal Injury Renal contusion, laceration, acute renal failure due toRenal contusion, laceration, acute renal failure due to
hypotension, and hypovolemiahypotension, and hypovolemia
Extremity InjuryExtremity Injury Traumatic amputation, fractures, crush injuries,Traumatic amputation, fractures, crush injuries,

Blast lung injury
• Damage to the delicate alveolar structures can occur from
exposure to the peak overpressure associated with the
initial blast wave and result in alveolar haemorrhages,
oedema and an exudative response manifested as bilateral
pulmonary infiltrates on chest X-ray (CXR) – ‘blast lung’.
•This condition is a marker of poor outcome and is an early
cause of death in patients exposed to ‘contained’ explosions
initiated in a building or semi-closed structure such as a
bus.

Pathophysiology of BLI
 The abrupt movement of the chest wall caused by blast waves does not
allow Propagation of pressure waves through the lung results in alveolar
wall injury and disruption of the alveolar/capillary interface
 The combination of injury to airway epithelium and the creation of
giant emphysema expose the patient to air penetration into the pleura and
mediastinum.
 Additionally, lung parenchyma is sheared away from the vascular tree by
acceleration–deceleration forces, resulting in the development
of alveolar–venous fistulas. Air is then forced into pulmonary
veins which can lead to air embolism .
 Signs of AE include air in the retinal vessels, arrhythmias, blindness, chest
pain, and neurological deficits.
 AE to the brain or heart may be the most common cause
of rapid death solely caused by BLI in immediate survivors and
often occurs at initiation of positive pressure ventilation (PPV)

 BLI is caused by the effects of the blast wave on the lung
parenchyma and has the highest morbidity and mortality
 Pulmonary barotrauma is the most common critical
injury to victims close to the blast center, and 45% of
fatalities of bomb explosions suffer from BLI
 In 17% of deaths lung injury is the sole finding
 One half of victims exposed to overpressures of 50–100 psi
will manifest pulmonary injury.
 Exposure to overpressures greater than 200 psi is
universally fatal

Symptoms and signs of BLI
 cough, dyspnea, chest pain, hypoxia,
tachycardia, apnea, wheezing,
and hemodynamic instability

Diagnosis of blast lung injury
 pulmonary contusions ( bilateral and diffuse )
(more severe than in open spaces.)
 Considerable blast loads cause ecchymoses, usually in
parallel bands which correspond to intercostal spaces
 higher energy blast waves cause
hemopneumothoraces,
traumatic emphysema,
and alveolovenous fistulas.

Chest X-ray
of a victim
of
bombing
attack
showing
typical
bilateral
patchy
infiltrates in
a butterfly
distribution.

 Clinical examination can be misleading as a tool for identifying
patients with BLI. Indeed, several victims of
terrorist attacks walked into the ER by themselves, only to quickly
deteriorate within minutes.
 Respiratory rate can aid in diagnosing BLI and victims of bomb
explosions with a mean initial respiratory rate of 25
breaths/minutes were significantly more likely to require
mechanical ventilation
 Chest radiographs are used to determine the presence and
severity of BLI and to monitor its progression
Frequent findings include lung contusions, pneumothoraces,
pneumo-mediastinum, and subcutaneous emphysema

Treatment of BLI
 management of BLI is challenging because of
the combination of hemodynamic shock, severe lung injury
and barotrauma, each of which may require
contradictory therapies.
 Adequate analgesia and aggressive chest physiotherapy are
fundamental elements of therapy. All victims with
suspected BLI should be given high-flow oxygen.
 Diuretics may be used in the setting
of hydrostatic fluid overload as evidenced by elevated
pulmonary capillary wedge pressures in hemodynamically
stable patients

 In victims suffering from BLI the presence of
pneumothoraces and hemothoraces should be
aggressively diagnosed and treated in order not to
further compromise lung function.
 The degree of injury to lung parenchyma is often
such that it is necessary to insert several chest
tubes in order to adequately drain the pleural
cavity and allow proper ventilation and
oxygenation

What Happens to the Brain
 Studies on rats have revealed that even when the
head is protected, blast injuries causes significant
neural damage
• Damage was particularly severe in the hippocampus of
rats
 It was hypothesized that the hippocampus was more
susceptible to injury due to its sensitivity to oxygen
deprivation
 Rats showed signs of cognitive impairments and
stress reactions following the injuries
• The blast wave or any penetrating injury may interfere with
blood flow in the brain, depriving the brain of needed
oxygen.

 Research used to focus primarily on damage to
gas filled organs (e.g. lungs or intestines), as
these were believed to be the organs most
significantly affected by blast exposure
• The brain was previously believed to be largely
protected by blasts due to the skull
• It has now been determined that the brain is just as
susceptible to blast injury as other organs
 In fact, TBI has been identified as one of the
more frequent injuries during the current
conflicts, and accounts for a greater proportion of
injuries than in any previous conflict

PhysicalPhysical
 HeadachesHeadaches
 DizzinessDizziness
 InsomniaInsomnia
 FatigueFatigue
 Uneven gaitUneven gait
 NauseaNausea
 Blurred VisionBlurred Vision
CognitiveCognitive
 Attention difficultiesAttention difficulties
 Concentration problemsConcentration problems
 Memory problemsMemory problems
 Orientation problemsOrientation problems
Signs and Symptoms of a Traumatic Brain Injury (TBISigns and Symptoms of a Traumatic Brain Injury (TBI))
Behavioral
Irritability
Depression
Anxiety
Sleep disturbances
Problems with emotional
control
Loss of initiative
Problems related to
employment, marriage,
relationships, and home
or school management

Blast AbdomenBlast Abdomen
Delayed onset > 8-36 hoursDelayed onset > 8-36 hours ––
a. Intestinal intra-wall hemorrhagesa. Intestinal intra-wall hemorrhages
b. Shearing of local mesenteric vesselsb. Shearing of local mesenteric vessels
c. Sub-capsular and retroperitoneal hematomas,c. Sub-capsular and retroperitoneal hematomas,
d. Rupture of liver and spleen, and testicular ruptured. Rupture of liver and spleen, and testicular rupture
SymptomsSymptoms –abdominal pain, nausea, vomiting,–abdominal pain, nausea, vomiting,
hematemesis (rare), rectal or testicular pain and tenesmushematemesis (rare), rectal or testicular pain and tenesmus
SignsSigns – abdominal tenderness, rebound, guarding, absent– abdominal tenderness, rebound, guarding, absent
bowel sounds, signs of hypovolemiabowel sounds, signs of hypovolemia
4.4. ManagementManagement – Resect small bowel contusions > 15 mm,– Resect small bowel contusions > 15 mm,
and large bowel contusions > 20 mmand large bowel contusions > 20 mm

what is the pattern of intra-
abdominal injury?
 Missiles generated by an explosion travel at a lower velocity
compared with GSW
(300–400 m/sec vs. 800–1,000 m/sec, respectively).
 The damage inflicted will depend on velocity, mass, and distance
from the explosion center
 Victims of terrorist explosions sustain multiple entry sites
 The pattern of intra-abdominal injury following terrorist explosions
is similar to the pattern of injury caused by GSW
 Injury is most often to the large and small bowel
and in nearly a fifth of cases there is injury to more
than one segment of bowel.
 Organs which are partially sheltered by bony structures,
such as the liver, spleen, and kidney,
are relatively more protected from injury

Abdominal wall
of a victim of
bombing
attack. Note
multiple
shrapnel entry
sites (black
arrows) and
penetrating
injury to the
small
bowel (white
arrows(.

laparotomies
 The approach to intra-abdominal injury following terrorist
explosions should be similar to injury caused by other mechanisms
of trauma.
 The rate of injury to hollow viscera is high and patients need
to be carefully evaluated for such injury.
 Imaging modalities such as focused abdominal sonography
for trauma (FAST) followed by computerized tomography should
be utilized extensively to diagnose intra-abdominal injury
 Diagnostic peritoneal lavage can be performed to rule out
injury to hollow viscera for victims undergoing other surgical
procedures. Due to the possibility of delayed presentation of
abdominal injury, catheters can be left in situ for up to 72 h for
continued abdominal monitoring.

Tympanic membrane rupture
 The ear is the most sensitive organ to blast injury, and auditory
injury has been reported in up to 41% of survivors following
bombing attacks
 Peak overpressures as low as 5 psi can rupture
the tympanic membrane (TM) and overpressures of 15 psi will
cause TM rupture in 50% of victims.
 Blast overpressure tears sensory cells from the basilar membrane,
which eventually heals with scar leading to continued symptoms
 Attack setting will determine the frequency of auditory injury and
ranges from 8% in open spaces to 50% in confined spaces
 Hearing loss may
be conductive due to TM rupture, ossicular damage, It may also
be sensorineural due to cochlear damage.

EarEar
Middle ear:Middle ear:
 Ruptured tympanic membrane (TM)Ruptured tympanic membrane (TM)
 Temporary conductive hearing lossTemporary conductive hearing loss
Inner ear:Inner ear:
 Temporary sensory hearing lossTemporary sensory hearing loss
 Permanent sensory hearing lossPermanent sensory hearing loss

 Immediate otoscopic examination for TM rupture should be
performed by an otolaryngologist in all cases. Treatment consists
of removal of debris from the external canal by suction under
microscope and keeping the ears dry.
 Symptoms and signs immediately following the attack included
aural fullness (88.2%), tinnitus (88.2%), otalgia (52.9%)
ear discharge (52.9%), and dizziness (41.2%).
 Normal hearing following TM rupture is uncommon and
hearing loss can present as mixed (61.8%), sensorineural (26.5%),
or conductive (8.8%). Even at 6-month follow-up some form of
hearing loss can persist in up to 80% of victims

 The role of TM rupture as a predictor of primary blast injury
is unclear. Several authors advocate the value of routine
otoscopy in triaging victims of terror bombing attacks
to identify those suffering from severe PBI in general,
and BLI in particular.
 Experience does not support such a pivotal role
for the otoscopic examination Indeed, more than one third
of victims with BLI do not have tympanic membrane rupture
at all. TM rupture is possibly associated with BLI in confined
spaces such as buses

 Blast lung injury
 Traumatic brain injury
 Blast abdomen
 T.M. rupture
 Burns among survivors

Burns among survivors
 High-explosives produce higher temperatures for shorter periods
of time, usually resulting in a fireball at the time of detonation.
 The intensely hot flames created cause burns of varying degrees
and depths, usually to victims in close proximity to the detonation
 victims with extensive burns (>30% body surface area) rarely
survive However, burns of lesser degrees are quite common
among survivors and necessitate adequate fluid resuscitation
as well as local wound treatment.
 Burns are usually located on exposed body parts,
 The essentials of managing burns following terrorist bombing
attacks are similar to burns caused by other causes.

 Terror-related burn victims also sustain a combination of
blast and penetrating injuries. Thus, early excision is
usually delayed until victims are stable enough.
 Autologous skin grafting may be delayed even further,
depending on the overall status of the patients.
 Early treatment of partial thickness burn wound consists of
mechanical debridement with wet gauzes.
 Burns involving small BSA are treated with topical
antimicrobial agents, while larger areas are treated with
homografts. Homografts cover the wounds for 10–14 days
and provide protection from desiccation and infection.

General management of blast
injuries
The structures injured by the primary blast wave, in order of prevalence, are
the middle ear, the lungs and the bowel.
 However, the commonest urgent clinical problem in survivors is penetrating
injury caused by blast-energised debris and fragments of the
exploding device.
 The deafness of blast victims caused by tympanic membrane
rupture makes communication difficult and may complicate early assessment.
 The management of penetrating wounds differs little from that of missile wounds
usually heavily contaminated with dirt, clothing and secondary missiles such
as wood, and other materials from the environment. Such contaminants
may be driven deeply into adjacent tissue planes opened up by the
force of the explosion.
 one cannot be sure of complete wound excision and it is imperative that wounds
should be left open at the end of the initial operation and delayed primary closure
performed.

conclusions
 Terror-related blast generated by suicide
bombing attacks results
injury, which is a combination of blast,
penetrating wounds, and burns.
 Victims of indoor attacks sustain
more BLI and burns.
 The work-up and management of these
victims includes extensive utilization of
imaging modalities and a
multi-disciplinary approach.

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