Blast injuries


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Blast injuries

  3. 3. A blast injury is a complex type of physicaltrauma resulting from direct or indirect exposureto an explosion.Blast injuries occur with the detonation of high-order explosives as well as the deflagration of loworder explosives. These injuries are compoundedwhen the explosion occurs in a confined space.
  5. 5. INTRODUCTIONBomb blast injuries to civilians are becomingincreasingly common over the last two decades mainlydue to terrorist attacks and are not only confined towars but also become pandemic with ever increasingacts of terrorism though the incidences are sporadic.Explosions cause life-endangering unique type ofinjuries involving multi organ system especially lungs& central nervous system in single or multiple victimssimultaneously thereby producing mass casualties.Every person from medical field or law enforcementagencies should be well conversant about thepattern, severity, mechanism, nature of injuries as theyhave to deal with hundreds to thousands of victimswith different types of injuries.
  6. 6. CLASSIFICATION OFEXPLOSIVEHigh-order explosives (HE) as a result of detonationproduces almost instantaneous high pressurerapidly expanding gases which compress thesurrounding air resulting into supersonic overpressurization shock or blast wave followed bynegative pressure (suction) wave which lasts forabout 5 times. Examples: - Trinitrotoulene (TNT), C-4, Semtex, nitroglycerin, dynamite and ammoniumnitrate fuel oil (ANFO).Low-order explosives (LE) undergo deflagrationinstead of detonation thereby releasing slow energyas compared to HEs resulting in subsonic explosionlacking over-pressurization blast wave Examples: -Pipe bombs, gunpowder and most pure petroleum-based bombs such as Molotov cocktails or aircraftimprovised as guided missiles.
  9. 9. FACTORS-THAT DETERMINE THEMAGNITUDE OF DAMAGESurroundings & Medium in whichit explodes.The distance from the incidence.Pressure wave & its duration.Amount and composition of theexplosive material.
  10. 10. CLASSIFICATION OF BLASTINJURIES Primary injuries Secondary injuries Tertiary injuries Quaternary injuries
  12. 12. CLASSIFICATION OF BLASTINJURIESPrimary injuries are caused by blast overpressure waves, or shock waves.These are especially likely when a person is close to explodingammunition, such as a land mine. Gas filled structures are mostsusceptible 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 ConcussionThe ears are most often affected by the overpressure, followed by the lungsand the hollow organs of the gastrointestinal tract. Gastrointestinalinjuries may present after a delay of hours or even days. Injury from blastoverpressure is a pressure and time dependent function. By increasingthe pressure or its duration, the severity of injury will also increase.In general, primary blast injuries are characterized by the absence ofexternal injuries; thus internal injuries are frequently unrecognized andtheir severity underestimated.
  13. 13. CLASSIFICATION OF BLAST INJURIESSecondary injuries are caused by fragmentation and otherobjects propelled by the explosion. Results from flyingdebris, broken glass, loose pieces and bomb fragmentsany body part can be affected. These injuries may affectany part of the body and sometimes result in penetratingtrauma with visible bleeding. At times the propelledobject may become embedded in the body, obstructingthe loss of blood to the outside. However, there may beextensive blood loss within the body cavities.Fragmentation wounds may be lethal and thereforemany anti-personnel bombs are designed to generatefragments.Most casualties are caused by secondary injuries. Someexplosives, such as nail bombs, are deliberately designedto increase the likelihood of secondary injuries. In otherinstances, the target provides the raw material for theobjects thrown into people, e.g., shattered glass from ablasted-out window or the glass facade of a building.
  14. 14. CLASSIFICATION OF BLAST INJURIESTertiary injuries:- Displacement of air by theexplosion creates a blast wind that can throw victimsagainst solid objects. Injuries resulting from this typeof traumatic impact are referred to as tertiary blastinjuries. Tertiary injuries may present as somecombination of blunt and penetratingtrauma, including bone fractures and coup contre-coupinjuries.(An injury, usually involving the brain, in which thetissue damage is on the side opposite the traumasite, as when a blow to the left side of the head resultsin brain damage on the right side.)Young children, because they weigh less thanadults, are at particular risk of tertiary injury.
  15. 15. CLASSIFICATION OF BLAST INJURIESQuaternary injuries or other miscellaneous named injuries, All explosion-related injuries, illnesses or diseases not due to primary, secondary, ortertiary mechanisms. Includes exacerbation or complications of existing conditions e.g. on 9/11 thecrash of two jet airplanes into the World Trade Centre created a relatively low-order pressure wave resulting into fire and building collapse producingthousands 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 HypertensionTraumatic amputations quickly result in death, and are thus rare in survivors,and are often accompanied by significant other injuries. The rate of eyeinjury may depend on the type of blast. Psychiatric injury, some of which maybe caused by neurological damage incurred during the blast, is the mostcommon quaternary injury, and post-traumatic stress disorder may affectpeople who are otherwise completely uninjured.
  16. 16. MECHANISM OF BLASTINJURIESThe explosive pressure that accompanies thebursting of bombs or shell, ruptures their casingand imparts a high velocity to the resultingfragments. These fragment have the potencial tocause more devastating injury to tissues thanbullets.In addiction, all explosives are accompanied by a“COMPLEX WAVE”. The main component of thiswave are a “BLAST WAVE”( known as dynamicoverpressure) with a positive and a negativephase, and the “BLAST WIND” ( mass movementof air). Injuries are mainly due to the initial shockwave, but are aggravated by the sub-atmosphericphase.
  17. 17. MECHANISM OF BLASTINJURIESThe mass movement of air blast (blast wind)disrupts the environment, throwing debris andpeople. This phenomenon results in injuriesranging from traumatic amputation todisruption.When the body is impacted by a blast pressurewave, it couples into the body and sets up aseries of. stress waves which are capable ofinjury, particularly at air-fluid interfaces.Thus, injuries to the ear, heart and GIT arenotable
  18. 18. NEUROTRAUMABlast injuries can cause hidden brain damage andpotential neurological consequences. Its complex clinicalsyndrome is caused by the combination of all blast effects,i.e., primary, secondary, tertiary and quaternary blastmechanisms. It is noteworthy that blast injuries usuallymanifest in a form of polytrauma, i.e. injury involving multipleorgans or organ systems. Bleeding from injured organs suchas lungs or bowel causes a lack of oxygen in all vital organs,including the brain. Damage of the lungs reduces the surfacefor oxygen uptake from the air, reducing the amount of theoxygen delivered to the brain. Tissue destruction initiatesthe synthesis and release of hormones or mediators into theblood which, when delivered to the brain, change itsfunction. Irritation of the nerve endings in injured peripheraltissue and/or organs also significantly contributes to blast-induced neurotrauma.…………….CONT………………………
  19. 19. NEUROTRAUMAIndividuals exposed to blast frequently manifest loss ofmemory for events before and after explosion,confusion, headache, impaired sense of reality, andreduced decision-making ability. Patients with braininjuries acquired in explosions often develop sudden,unexpected brain swelling andcerebral vasospasm despite continuous monitoring.However, the first symptoms of blast-inducedneurotrauma (BINT) may occur months or even yearsafter the initial event, and are therefore categorizedas secondary brain injuries. The broad variety ofsymptoms includes weight loss, hormone imbalance,chronic fatigue, headache, and problems in memory,speech and balance. These changes are oftendebilitating, interfering with daily activities. BecauseBINT in blast victims is underestimated, valuable timeis often lost for preventive therapy and/or timelyrehabilitation.
  20. 20. EFFECTS OF INJURIES ONHUMAN BODYDisruptive Effect: It affects the personwho is quite close to bomb. Whenbomb explodes, the person may beblown into pieces. If the victim is abit far away, he may have his limbblown off. These disruptive injuriesare quite extensive and victim diesimmediately.
  22. 22. EFFECTS OF INJURIES ONHUMAN BODYShock Wave: It is also called „air blast‟. As a result of blasta zone of compressed air is created and it travels further.This wave of compression is followed by a wave of negativepressure. So, the victim bears first impact of compressed airand then negative pressure. The high pressured compressedair can knock down a person easily. This wave causesmaximum damage to lungs. It leads to disruptive effectcausing rupture of alveolar septa and cause haemorrhage inalveoli. 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 tympanicmembrane is ruptured. The alimentary system also suffersdamage due to the pressure of air. The stomach andintestine may rupture. The solid tissues likeliver, kidneys, etc. resist the impact of shock wave betterthan hollow organs like stomach containing air.
  23. 23. SHOCK WAVE
  24. 24. EFFECTS OF INJURIES ONHUMAN BODYBurns: When a bomb is exploded,the temperature reaches around2000°C and heated gases arereleased. They produce burns onvictims who are in vicinity of thebomb blast. The exposed areas ofthe body are severely affected ascompared to the covered ones.
  25. 25. BURNS
  26. 26. EFFECTS OF INJURIES ONHUMAN BODYFlying Missiles: These may originate frombomb itself as some bombs containmetal pins, small metal balls or metallicnails which act as missiles and causeinjuries to all those present around thesite of the bomb blast. Sometimes, as aresult of shock wave, small objects mayalso be thrown as missiles and maycause injuries. The small pins or metalnails used in the bomb may causemultiple abrasions and lacerations dueto these flying missiles.
  28. 28. EFFECTS OF INJURIES ONHUMAN BODYFalling Masonry: Sometimes a bombblast in a building may result in itscollapse due to shock wave andpersons may be caught in thefalling debris. People may suffertraumatic asphyxia once caughtin the debris. They may sustainhead injury or other injuries dueto falling stones.
  30. 30. EFFECTS OF INJURIES ONHUMAN BODYAsphyxia: In bomb blast, a lot ofgases are produced which cancause asphyxia, if the explosionhas occurred in a closed area.Common gases are carbondioxide, carbon monoxide, andhydrogen sulphide.
  31. 31. ASPHYXIA
  32. 32. SELECTED BLAST INJURIESRespiratory system The Blast lung (Pulmonary barotraumas)the most common fatal primary blast injury. “Butterfly” pattern on chest X-ray is thecharacteristic 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 highestmortality and morbidity and consumed themost resources in the major bombings.
  33. 33. SELECTED BLAST INJURIESEarDeafness.Rupture/ perforation of TympanicMembraneFracture/ dislocation of ossiclesCochlear damageForeign body in earLong-term ENT sequel--- vertigo/tinnitus, dizziness and ear pain.
  34. 34. SELECTED BLAST INJURIESCentral nervous systemHeadache, fatigue, poorconcentration, lethargy, depression,anxiety, insomnia, loss of memoryClosed and open brain injuryIntracranial, subdural and extraduralhaemorrhagesStrokeSpinal cord injury
  35. 35. SELECTED BLAST INJURIESAbdominal InjurySymptoms: Abdominal pain, nausea,vomiting, haematemesis, rectalpain, tenesmus, testicular pain,unexplained hypovolemia.Acute/delayed signs of peritonitisMesenteric shear injuries.Blunt trauma to the abdomen cancause solid organ injuries like liver,renal and splenic contusion,lacerations and haemorrhage.
  36. 36. MEDICO LEGAL ASPECTSInjuries from bombs used to be mainlyaccidental in the past. Their homicidal use isnow common with the use of bombs byterrorists to destroy specific targets, such asgovernment building, bridges, publictransport vehicles, premises occupied bytheir opponents. The composition of bombsvaries.Few examples of bombs in common use includeTime Bomb, Impact bomb, Napalm bomb,Molotiv Cocktail, etc.
  38. 38. MEDICO LEGAL ASPECTSThe main concern in modern era is the destructionof commercial aircraft in flight has importantmedico-legal implications. The main difficultyfacing the investigators is to distinguish sabotagefrom explosive decompression due to structuralfailure. This issue is important as theresponsibility of insurance claims passes from“ALL RISK” to “WAR RISKS”. In these days ofadvanced technology, any unexplained disaster inair should be suspected to be due to sabotageuntil the contrary is proved. The major part of theaircraft would be found scattered over wide areawithout any logical pattern in a case of mid-airexplosion caused by sabotage.
  39. 39. SABOTAGE
  40. 40. MEDICO LEGAL ASPECTSForensic personnel should be familiar with the patternand severity of injuries so that the proper injury reportin case of survivors and post mortem report in casesof death of persons can be prepared and collectproperly any foreign body (shrapnel, empty shell etc.)and hand over to investigation officer.Recognition, proper interpretation and documentationof these types of injuries would assist withreconstruction of the incident.Sometimes Forensic personnel have to give opinionregarding time of injuries so that actual and needyshould get the benefit of state machinery and ex gratiaannounced by the government. Forensic personnelshould have eagle‟s eyes to catch the moles.
  41. 41. MEDICO LEGAL ASPECTSFollowing things are of vital importance inbomb 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
  42. 42. MEDICO LEGAL ASPECTSWHETHER A BOMB HAS CAUSED THE EXPLOSION Full body photographs and complete X-rays of the wholebody are indicated before the clothes are removed. Anyradio-opaque fragments and radiolucent material (paperfragments, wood and plastic) may be component of anexplosive 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 duringautopsy. Toxicological analysis may help. Extensive burns are usually not caused by localised bombexplosion.
  43. 43. MEDICO LEGAL ASPECTSNUMBER OF DEAD PERSONSA major initial problem,correct fragment are to beallocated to the rightindividuals.
  44. 44. MEDICO LEGAL ASPECTSIDENTIFICATION OF THE DEADThe injuries can be extreme and thus makethe identification and interpretation difficultfor the autopsy surgeon. All body parts andclothing are recovered (clothing is submittedin air tight containers). Dentition, dentures and artificial teeth alsohelp in identification. Fingerprinting may also help.
  45. 45. MEDICO LEGAL ASPECTSENLISTING THE INJURIESThese include:-External and internal injuriesExternal injuries:- total disintegration indicates high- order condensedexplosive at close range. There may be mangling of body near explosion with parts ofextremities amputated; cranio-facial injuries re seen in a case ofsuicide. Lower limb amputation is typical of standing or seatedindividual. Hand injuries are seen, of explosive was held. There may be projectile injury. Punctate laceration, dust tattooing and black soiling fromexplosive materials may be seen. “TRIAD” of bruises, abrasions andpuncture lacerations with tattooing of the body indicates bombexplosion. Injuries may be seen due to fallen rubble. Burns(flash burns and singed hair seen on victims in immediatevicinity).
  46. 46. MEDICO LEGAL ASPECTSInternal injuries:- have been described in detail under the headingsof :- PRIMARY INJURIES SECONDARY INJURIES TERTIARY INJURIES QUATERNARY INJURIES&SELECTED BLAST INJURIES• &&&&&
  47. 47. MEDICO LEGAL ASPECTSCAUSE OF DEATHDeath may result from variety of causes, i.e. Complete disintegration of body as a result of blasteffect while in the vicinity of blast. (Blast shock) While one is at some distance away from thesite, death may result from burns, blunt forceinjuries, and falling debris Crush syndrome/ asphyxia (due to inhalation ofproducts of combustion) A victim may be little injured but may die of profoundshock Another possible cause of rapid death----Systemic airembolism
  50. 50. POST-MORTEM EXAMINATIONThe post-mortem examination of bomb blast cases should be carefullydone, and following guidelines should be followed:Identification: It poses serious problems as bodies are mutilated anddisfigured. Sometimes, even pieces of various bodies may be foundtogether. In all such cases, first the reconstruction of bodies shouldbe done, by organs. The number of heads show the number ofpersons killed. The soft parts should be carefully collected andapplied in anatomical positions to know the side to which theybelong. Apart from injuries due to burns, flying missiles, fallingdebris, and the effect of poisonous gases liberated by the explosive,the blat wave produces scattered foci of small haemorrhages inbrain, lungs, bowel, and in mesentery. Passive hyperaemia and/oroedema cause serious secondary brain and lung lesion. Intracranialhaemorrhages, contusion of brain and heart, and aortic injuries,ruptured stomach / bowel and bladder may be seen.…………………….cont…………………………..
  51. 51. POST-MORTEM EXAMINATIONFurther identification can be done by:(a) X-ray examination of skull and then subjecting to super-impositiontechnique.(b) Matching dental record if previous records are available. Compare dentalfillings and old fracture in dental record.(c) Preserving tissues, like parts of liver and bone marrow for DNA test toestablish identity.Clothing: It must be thoroughly inspected and any pieces of explosives maybe preserved. The clothes should be preserved and sent for forensicscience laboratory.Injuries: All injuries should be carefully noted. Any missing parts should beclearly mentioned in post-mortem report.The cause of death should be ascertained taking into consideration allinjuries. Usually shock is the cause of death. Death may be instant ifthe person is blown into pieces.
  53. 53. CONCLUSIONS Blast injuries are not confined to the battlefield but arepandemic Seal the hospital entrances and scan the hospital properly toprevent the tactic of setting of dual explosion to producemore mortalities as first explosion for civilians and secondfor caregivers and rescuers. Consider exposure to carbon monoxide, cyanide, ormethemoglobin-forming toxins in industrial as well asterrorist explosion. Penetrating/blunt trauma to anybody surface is the mostcommon injury seen among survivors. Patients should require 4-6 hours of observation. Radiological imaging of the head, chest and abdomen willhelp with the early identification of blast lung injury, headinjury, abdominal injury, eye and sinus injuries, as well asany penetration by foreign bodies. Isolated TM rupture is not a reliable marker of morbidity. Delay the primary closure in contaminated wound and givetetanus toxoid and anti-tetanus serum.