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BLAST INJURY

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A POWER POINT PRESENTATION BY

DR.SANGEETA CHOWDHRY &

DR.SUNIL SHARMA DEPARTMENT OF FORENSIC MEDICINE

& TOXICOLOGY

GOVT. MEDICAL COLLEGE JAMMU (JAMMU AND KASHMIR)

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A blast injury is a complex type of physical trauma resulting from direct or indirect exposure to an explosion. Blast injuries occur with the detonation of high-order explosives as well as the deflagration of low order explosives. These injuries are compounded when the explosion occurs in a confined space.

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CONTENTS

INTRODUCTION.CLASSIFICATION OF EXPLOSIVE. CLASSIFICATION OF INJURIES.MECHANISM.NEUROTRAUMA. EFFECTS OF INJURIES ON HUMAN BODY. SELECTED BLAST INJURIES.MEDICO-LEGAL ASPECT.POST –MORTEM FINDINGS.CONCLUSION

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INTRODUCTIONBomb blast injuries to civilians are becoming increasingly

common over the last two decades mainly due to terrorist attacks and are not only confined to wars but also become pandemic with ever increasing acts of terrorism though the incidences are sporadic. Explosions cause life-endangering unique type of injuries involving multi organ system especially lungs & central nervous system in single or multiple victims simultaneously thereby producing mass casualties.

Every person from medical field or law enforcement agencies should be well conversant about the pattern, severity, mechanism, nature of injuries as they have to deal with hundreds to thousands of victims with different types of injuries.

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CLASSIFICATION OF EXPLOSIVE

High-order explosives (HE) as a result of detonation produces almost instantaneous high pressure rapidly expanding gases which compress the surrounding air resulting into supersonic over pressurization shock or blast wave followed by negative pressure (suction) wave which lasts for about 5 times. Examples: - Trinitrotoulene (TNT), C-4, Semtex, nitroglycerin, dynamite and ammonium nitrate fuel oil (ANFO).

Low-order explosives (LE) undergo deflagration instead of detonation thereby releasing slow energy as compared to HEs resulting in subsonic explosion lacking over-pressurization blast wave Examples: -Pipe bombs, gunpowder and most pure petroleum-based bombs such as Molotov cocktails or aircraft improvised as guided missiles.

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HIGH-ORDER EXPLOSIVES

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LOW-ORDER EXPLOSIVES

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FACTORS-THAT DETERMINE THE MAGNITUDE OF DAMAGE

Surroundings & Medium in which it explodes.

The distance from the incidence.Pressure wave & its duration.Amount and composition of the

explosive material.

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CLASSIFICATION OF BLAST INJURIES

Primary injuries Secondary injuries Tertiary injuries Quaternary injuries

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ILLUSTRATIONS OF PRIMARY, SECONDARY AND TERTIARY INJURIES FROM BLAST

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CLASSIFICATION OF BLAST INJURIES

Primary injuries are caused by blast overpressure waves, or shock waves. These are especially likely when a person is close to exploding ammunition, such as a land mine. Gas filled structures are most susceptible as air is easily compressible than water.

lungs, GI tract, Ear, Eye, Brain Blast lung (pulmonary barotrauma) Abdominal haemorrhage and perforation TM rupture and middle ear damage Globe (eye) rupture Concussion

The ears are most often affected by the overpressure, followed by the lungs and the hollow organs of the gastrointestinal tract. Gastrointestinal injuries may present after a delay of hours or even days. Injury from blast overpressure is a pressure and time dependent function. By increasing the pressure or its duration, the severity of injury will also increase.

In general, primary blast injuries are characterized by the absence of external injuries; thus internal injuries are frequently unrecognized and their severity underestimated.

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CLASSIFICATION OF BLAST INJURIES Secondary injuries are caused by fragmentation and other

objects propelled by the explosion. Results from flying debris, broken glass, loose pieces and bomb fragments any body part can be affected.  These injuries may affect any part of the body and sometimes result in penetrating trauma with visible bleeding. At times the propelled object may become embedded in the body, obstructing the loss of blood to the outside. However, there may be extensive blood loss within the body cavities. Fragmentation wounds may be lethal and therefore many anti-personnel bombs are designed to generate fragments.

Most casualties are caused by secondary injuries. Some explosives, such as nail bombs, are deliberately designed to increase the likelihood of secondary injuries. In other instances, the target provides the raw material for the objects thrown into people, e.g., shattered glass from a blasted-out window or the glass facade of a building.

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CLASSIFICATION OF BLAST INJURIES

Tertiary injuries:- Displacement of air by the

explosion creates a blast wind that can throw victims against solid objects. Injuries resulting from this type of traumatic impact are referred to as tertiary blast injuries. Tertiary injuries may present as some combination of blunt and penetrating trauma, including bone fractures and coup contre-coup injuries.

(An injury, usually involving the brain, in which the tissue damage is on the side opposite the trauma site, as when a blow to the left side of the head results in brain damage on the right side.)

Young children, because they weigh less than adults, are at particular risk of tertiary injury.

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CLASSIFICATION OF BLAST INJURIES

Quaternary injuries or other miscellaneous named injuries, All explosion-related injuries, illnesses or diseases not due to primary, secondary, or tertiary mechanisms.

Includes exacerbation or complications of existing conditions e.g. on 9/11 the crash of two jet airplanes into the World Trade Centre created a relatively low-order pressure wave resulting into fire and building collapse producing thousands of mortalities. Any body part can be affected -

Burns (flash, partial, and full thickness) Crush injuries Closed and open brain injury Asthma, COPD, or other breathing problems from dust, smoke, or toxic fumes Angina Hyperglycemia Hypertension

Traumatic amputations quickly result in death, and are thus rare in survivors, and are often accompanied by significant other injuries.  The rate of eye injury may depend on the type of blast. Psychiatric injury, some of which may be caused by neurological damage incurred during the blast, is the most common quaternary injury, and post-traumatic stress disorder may affect people who are otherwise completely uninjured.

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MECHANISM OF BLAST INJURIES

The explosive pressure that accompanies the bursting of bombs or shell, ruptures their casing and imparts a high velocity to the resulting fragments. These fragment have the potencial to cause more devastating injury to tissues than bullets.

In addiction, all explosives are accompanied by a “COMPLEX WAVE”. The main component of this wave are a “BLAST WAVE”( known as dynamic overpressure) with a positive and a negative phase, and the “BLAST WIND” ( mass movement of air). Injuries are mainly due to the initial shock wave, but are aggravated by the sub-atmospheric phase.

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MECHANISM OF BLAST INJURIES

The mass movement of air blast (blast wind) disrupts the environment, throwing debris and people. This phenomenon results in injuries ranging from traumatic amputation to disruption.

When the body is impacted by a blast pressure wave, it couples into the body and sets up a series of. stress waves which are capable of injury, particularly at air-fluid interfaces. Thus, injuries to the ear, heart and GIT are notable

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NEUROTRAUMA

Blast injuries can cause hidden brain damage and potential neurological consequences. Its complex clinical syndrome is caused by the combination of all blast effects, i.e., primary, secondary, tertiary and quaternary blast mechanisms. It is noteworthy that blast injuries usually manifest in a form of polytrauma, i.e. injury involving multiple organs or organ systems. Bleeding from injured organs such as lungs or bowel causes a lack of oxygen in all vital organs, including the brain. Damage of the lungs reduces the surface for oxygen uptake from the air, reducing the amount of the oxygen delivered to the brain. Tissue destruction initiates the synthesis and release of hormones or mediators into the blood which, when delivered to the brain, change its function. Irritation of the nerve endings in injured peripheral tissue and/or organs also significantly contributes to blast-induced neurotrauma.

…………….CONT………………………

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NEUROTRAUMA

Individuals exposed to blast frequently manifest loss of memory for events before and after explosion, confusion, headache, impaired sense of reality, and reduced decision-making ability. Patients with brain injuries acquired in explosions often develop sudden, unexpected brain swelling and cerebral vasospasm despite continuous monitoring. However, the first symptoms of blast-induced neurotrauma (BINT) may occur months or even years after the initial event, and are therefore categorized as secondary brain injuries. The broad variety of symptoms includes weight loss, hormone imbalance, chronic fatigue, headache, and problems in memory, speech and balance. These changes are often debilitating, interfering with daily activities. Because BINT in blast victims is underestimated, valuable time is often lost for preventive therapy and/or timely rehabilitation.

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EFFECTS OF INJURIES ON HUMAN BODY

Disruptive Effect: It affects the person who is quite close to bomb. When bomb explodes, the person may be blown into pieces. If the victim is a bit far away, he may have his limb blown off. These disruptive injuries are quite extensive and victim dies immediately.

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DISRUPTIVE EFFECT

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EFFECTS OF INJURIES ON HUMAN BODY

Shock Wave: It is also called ‘air blast’. As a result of blast a zone of compressed air is created and it travels further. This wave of compression is followed by a wave of negative pressure. So, the victim bears first impact of compressed air and then negative pressure. The high pressured compressed air can knock down a person easily. This wave causes maximum damage to lungs. It leads to disruptive effect causing rupture of alveolar septa and cause haemorrhage in alveoli. The air passages are filled up with blood and fluid. The fluid in the alveolar space can cause respiratory failure. These injuries are sometimes referred to as ‘blast lung.’

The shock wave also causes damage to ears. The tympanic membrane is ruptured. The alimentary system also suffers damage due to the pressure of air. The stomach and intestine may rupture. The solid tissues like liver, kidneys, etc. resist the impact of shock wave better than hollow organs like stomach containing air.

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SHOCK WAVE

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EFFECTS OF INJURIES ON HUMAN BODY

Burns: When a bomb is exploded, the temperature reaches around 2000°C and heated gases are released. They produce burns on victims who are in vicinity of the bomb blast. The exposed areas of the body are severely affected as compared to the covered ones.

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BURNS

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EFFECTS OF INJURIES ON HUMAN BODY

Flying Missiles: These may originate from bomb itself as some bombs contain metal pins, small metal balls or metallic nails which act as missiles and cause injuries to all those present around the site of the bomb blast. Sometimes, as a result of shock wave, small objects may also be thrown as missiles and may cause injuries. The small pins or metal nails used in the bomb may cause multiple abrasions and lacerations due to these flying missiles.

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FLYING MISSILES

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EFFECTS OF INJURIES ON HUMAN BODY

Falling Masonry: Sometimes a bomb blast in a building may result in its collapse due to shock wave and persons may be caught in the falling debris. People may suffer traumatic asphyxia once caught in the debris. They may sustain head injury or other injuries due to falling stones.

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FALLING MASONRY

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EFFECTS OF INJURIES ON HUMAN BODY

Asphyxia: In bomb blast, a lot of gases are produced which can cause asphyxia, if the explosion has occurred in a closed area. Common gases are carbon dioxide, carbon monoxide, and hydrogen sulphide.

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ASPHYXIA

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SELECTED BLAST INJURIES

Respiratory system  The Blast lung (Pulmonary barotraumas) the most

common fatal primary blast injury. “Butterfly” pattern on chest X-ray is the

characteristic of blast lung. Bronchopleural fistulae, pneumo-thoraces,

pseudocyst formations. ARDS and air embolism Diffuse lung damage even after two days. Pulmonary blast injury carries the highest mortality

and morbidity and consumed the most resources in the major bombings.

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SELECTED BLAST INJURIES

EarDeafness.Rupture/ perforation of Tympanic

MembraneFracture/ dislocation of ossiclesCochlear damageForeign body in earLong-term ENT sequel--- vertigo/

tinnitus, dizziness and ear pain.

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SELECTED BLAST INJURIES

Central nervous system Headache, fatigue, poor

concentration, lethargy, depression, anxiety, insomnia, loss of memory

Closed and open brain injuryIntracranial, subdural and extradural

haemorrhagesStrokeSpinal cord injury

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SELECTED BLAST INJURIES

Abdominal Injury Symptoms: Abdominal pain, nausea,

vomiting, haematemesis, rectal pain, tenesmus, testicular pain, unexplained hypovolemia.

Acute/delayed signs of peritonitisMesenteric shear injuries.Blunt trauma to the abdomen can cause

solid organ injuries like liver, renal and splenic contusion, lacerations and haemorrhage.

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MEDICO LEGAL ASPECTS

Injuries from bombs used to be mainly accidental in the past. Their homicidal use is now common with the use of bombs by terrorists to destroy specific targets, such as government building, bridges, public transport vehicles, premises occupied by their opponents. The composition of bombs varies.

Few examples of bombs in common use include Time Bomb, Impact bomb, Napalm bomb, Molotiv Cocktail, etc.

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TIME BOMBIMPACT BOMB

NAPALM BOMB MOLOTIV COCKTAIL BOMB

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MEDICO LEGAL ASPECTS

The main concern in modern era is the destruction of commercial aircraft in flight has important medico-legal implications. The main difficulty facing the investigators is to distinguish sabotage from explosive decompression due to structural failure. This issue is important as the responsibility of insurance claims passes from “ALL RISK” to “WAR RISKS”. In these days of advanced technology, any unexplained disaster in air should be suspected to be due to sabotage until the contrary is proved. The major part of the aircraft would be found scattered over wide area without any logical pattern in a case of mid-air explosion caused by sabotage.

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SABOTAGE

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MEDICO LEGAL ASPECTS

Forensic personnel should be familiar with the pattern and severity of injuries so that the proper injury report in case of survivors and post mortem report in cases of death of persons can be prepared and collect properly any foreign body (shrapnel, empty shell etc.) and hand over to investigation officer. Recognition, proper interpretation and documentation of these types of injuries would assist with reconstruction of the incident.

Sometimes Forensic personnel have to give opinion regarding time of injuries so that actual and needy should get the benefit of state machinery and ex gratia announced by the government. Forensic personnel should have eagle’s eyes to catch the moles.

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MEDICO LEGAL ASPECTS

Following things are of vital importance in bomb blasts/explosions

Whether a bomb has caused the explosion Number of dead persons Identification of the dead Enlisting the injuries External Internal Cause of death Circumstances of death

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MEDICO LEGAL ASPECTS

WHETHER A BOMB HAS CAUSED THE EXPLOSION

Full body photographs and complete X-rays of the whole body are indicated before the clothes are removed. Any radio-opaque fragments and radiolucent material (paper fragments, wood and plastic) may be component of an explosive device.

Residues are either burnt(black or gray) or unburnt (yellow, brown, gray) material. Swab the soiled skin and hands. Collect hair and fingernail scrapings.

Foreign body (shrapnel or empty shell) may be found during autopsy.

Toxicological analysis may help. Extensive burns are usually not caused by localised bomb

explosion.

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MEDICO LEGAL ASPECTS

NUMBER OF DEAD PERSONS

A major initial problem, correct fragment are to be allocated to the right individuals.

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MEDICO LEGAL ASPECTS

IDENTIFICATION OF THE DEAD

The injuries can be extreme and thus make the identification and interpretation difficult for the autopsy surgeon. All body parts and clothing are recovered (clothing is submitted in air tight containers).

Dentition, dentures and artificial teeth also help in identification.

Fingerprinting may also help.

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MEDICO LEGAL ASPECTSENLISTING THE INJURIES

These include:- External and internal injuriesExternal injuries:- total disintegration indicates high- order

condensed explosive at close range. There may be mangling of body near explosion with parts of

extremities amputated; cranio-facial injuries re seen in a case of suicide. Lower limb amputation is typical of standing or seated individual. Hand injuries are seen, of explosive was held.

There may be projectile injury. Punctate laceration, dust tattooing and black soiling from

explosive materials may be seen. “TRIAD” of bruises, abrasions and puncture lacerations with tattooing of the body indicates bomb explosion.

Injuries may be seen due to fallen rubble. Burns(flash burns and singed hair seen on victims in immediate

vicinity).

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MEDICO LEGAL ASPECTS

Internal injuries:- have been described in detail under the headings of :-

PRIMARY INJURIES  SECONDARY INJURIES  TERTIARY INJURIES  QUATERNARY INJURIES &

SELECTED BLAST INJURIES

• &&&&&

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MEDICO LEGAL ASPECTS

CAUSE OF DEATHDeath may result from variety of causes, i.e. Complete disintegration of body as a result of blast

effect while in the vicinity of blast. (Blast shock) While one is at some distance away from the site,

death may result from burns, blunt force injuries, and falling debris

Crush syndrome/ asphyxia (due to inhalation of products of combustion)

A victim may be little injured but may die of profound shock

Another possible cause of rapid death----Systemic air embolism

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MEDICO LEGAL ASPECTS

CIRCUMSTANCES OF DEATH

Need to looked for.

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CIRCUMSTANCES OF DEATH

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POST-MORTEM EXAMINATION

The post-mortem examination of bomb blast cases should be carefully done, and following guidelines should be followed:

Identification: It poses serious problems as bodies are mutilated and disfigured. Sometimes, even pieces of various bodies may be found together. In all such cases, first the reconstruction of bodies should be done, by organs. The number of heads show the number of persons killed. The soft parts should be carefully collected and applied in anatomical positions to know the side to which they belong. Apart from injuries due to burns, flying missiles, falling debris, and the effect of poisonous gases liberated by the explosive, the blat wave produces scattered foci of small haemorrhages in brain, lungs, bowel, and in mesentery. Passive hyperaemia and/or oedema cause serious secondary brain and lung lesion. Intracranial haemorrhages, contusion of brain and heart, and aortic injuries, ruptured stomach / bowel and bladder may be seen.

…………………….cont………………………….. 

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POST-MORTEM EXAMINATION

Further identification can be done by:(a) X-ray examination of skull and then subjecting to super-imposition

technique.(b) Matching dental record if previous records are available. Compare dental

fillings and old fracture in dental record.(c) Preserving tissues, like parts of liver and bone marrow for DNA test to

establish identity.

Clothing: It must be thoroughly inspected and any pieces of explosives may be preserved. The clothes should be preserved and sent for forensic science laboratory.

Injuries: All injuries should be carefully noted. Any missing parts should be clearly mentioned in post-mortem report.

The cause of death should be ascertained taking into consideration all injuries. Usually shock is the cause of death. Death may be instant if the person is blown into pieces.

 

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CONCLUSIONS

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CONCLUSIONS

Blast injuries are not confined to the battlefield but are pandemic Seal the hospital entrances and scan the hospital properly to prevent

the tactic of setting of dual explosion to produce more mortalities as first explosion for civilians and second for caregivers and rescuers.

Consider exposure to carbon monoxide, cyanide, or methemoglobin-forming toxins in industrial as well as terrorist explosion.

Penetrating/blunt trauma to anybody surface is the most common injury seen among survivors.

Patients should require 4-6 hours of observation. Radiological imaging of the head, chest and abdomen will help with

the early identification of blast lung injury, head injury, abdominal injury, eye and sinus injuries, as well as any penetration by foreign bodies.

Isolated TM rupture is not a reliable marker of morbidity. Delay the primary closure in contaminated wound and give tetanus

toxoid and anti-tetanus serum.

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