Blast injuries

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2. A POWER POINT PRESENTATIONBYDR.SANGEETA CHOWDHRY&DR.SUNIL SHARMADEPARTMENT OF FORENSIC MEDICINE&TOXICOLOGYGOVT. MEDICAL COLLEGEJAMMU (JAMMU AND KASHMIR) 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. 4. CONTENTSINTRODUCTION.CLASSIFICATION OF EXPLOSIVE.CLASSIFICATION OF INJURIES.MECHANISM.NEUROTRAUMA.EFFECTS OF INJURIES ON HUMAN BODY.SELECTED BLAST INJURIES.MEDICO-LEGAL ASPECT.POST MORTEM FINDINGS.CONCLUSION 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. 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. 7. HIGH-ORDER EXPLOSIVES 8. LOW-ORDER EXPLOSIVES 9. FACTORS-THAT DETERMINE THEMAGNITUDE OF DAMAGESurroundings & Medium in whichit explodes.The distance from the incidence.Pressure wave & its duration.Amount and composition of theexplosive material. 10. CLASSIFICATION OF BLASTINJURIES Primary injuries Secondary injuries Tertiary injuries Quaternary injuries 11. ILLUSTRATIONS OF PRIMARY, SECONDARY AND TERTIARYINJURIES FROM BLAST 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. 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. 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. 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. 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 aCOMPLEX 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. 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. 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. 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. 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. 21. DISRUPTIVE EFFECT 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