COORDINATEDCOORDINATED EFFORTSEFFORTS OFOF VHA,VHA, DODDOD ANDAND USUHSUSUHS TOTO DEVELOPDEVELOP EDUCATIONALEDUCATIONAL MATERIALS:MATERIALS: PLPL 107-287107-287 OfficesOffices ofof PCSPCS andand OPHEHOPHEH Thanks:Thanks: AbidAbid RahmanRahman Ph.D.,Ph.D., SusanSusan MatherMather MDMD MPHMPH andand othersothers includingincluding ColCol DavidDavid Burris,Burris, CreightonCreighton BB Wright,Wright, HowardHoward Champion,Champion, MichaelMichael JJ Hodgson,Hodgson, VirginiaVirginia Hayes,Hayes, ArtieArtie Shelton,Shelton, BrianBrian JJ McKinnonMcKinnon CmdrCmdr USNUSN forfor TMTM guidanceguidance BlastsBlasts andand explosions:explosions: physical,physical, medical,medical, andand triagetriage considerationsconsiderations RelationshipsRelationships toto emergencyemergency cachescaches TBITBI ProgramProgram relationshipsrelationships FutureFuture ProgramsPrograms GOALSGOALS ofof PROGRAMPROGRAM •• UnderstandUnderstand thethe mechanismsmechanisms ofof blastsblasts andand blastblast injuriesinjuries –– TypesTypes ofof explosionsexplosions •• UnderstandUnderstand thethe medicalmedical consequencesconsequences andand syndromessyndromes fromfrom blastblast injuryinjury –– TypesTypes andand classificationclassification ofof injuriesinjuries •• BeBe ableable toto applyapply aa triagetriage algorithmalgorithm toto blastblast injuryinjury –– TriageTriage algorithmalgorithm •• OtherOther treatmenttreatment considerationsconsiderations ExplosiveExplosive EffectsEffects •• BlastBlast PressurePressure WaveWave –– Over-pressureOver-pressure –– Under-pressureUnder-pressure •• FragmentFragment effecteffect •• ThermalThermal (incendiary)(incendiary) effecteffect •• SecondarySecondary effectseffects –– SeismicSeismic –– ReflectionReflection ExplosiveExplosive EffectsEffects BlastBlast PressurePressure WaveWave A: time zero: begin of explosion B: end of over-pressurization wave C: end of underpressurization wave B’: end of over-pressurization wave for nhanced blast devices C’: end of underpressurization wave for enhanced blast devices 2 psi: threshold for pulmonary injury 1 psi: threshold for tympanic membrane rupture Atmospheric pressure A B B’ C C’ A X – axis: time Y-axis: pressure ExplosionExplosionExplosion Volume Compressed Blast 10 times Gas Wave Greater (3000 to 8000 m/sec) Pressure Atmospheric Pressure Time HopkinsonHopkinsonHopkinson’s’’ss RuleRuleRule •• PeakPeak overpressureoverpressure directlydirectly relatedrelated toto thethe energyenergy ofof thethe blastblast andand inverselyinversely proportionalproportional toto thethe cubecube ofof thethe distancedistance fromfrom it’sit’s epicenterepicenter BlastBlastBlast EffectsEffectsEffects BlastBlast WaveWave –– ShockShock WaveWave FrontFront Hydrostatic Pressure –– BlastBlast WindWind (dynamic(dynamic pressure)pressure) (ie: sound) Fireball – Thermal Output (heat) BlastBlast InjuriesInjuries •• PrimaryPrimary BlastBlast InjuriesInjuries –– DirectDirect effecteffect ofof blastblast wavewave •• SecondarySecondary BlastBlast InjuriesInjuries –– ObjectsObjects strikestrike individualindividual •• TertiaryTertiary BlastBlast InjuriesInjuries –– IndividualIndividual strikesstrikes objectsobjects •• QuaternaryQuaternary BlastBlast InjuriesInjuries –– OtherOther effectseffects –– burns, burns, infections,infections, crushcrush injuries,injuries, delayeddelayed collapsecollapse INJURYINJURY DISTRIBUTIONDISTRIBUTION •• ConventionalConventional explosiveexplosive –– BluntBlunt traumatrauma –– PenetratingPenetrating traumatrauma –– InhalationInhalation injuryinjury –– ThermalThermal injuryinjury // BurnsBurns –– RelativelyRelatively lessless primaryprimary blastblast injuryinjury •• EnhancedEnhanced blastblast devicesdevices // vehiclesvehicles /enclosed/enclosed spacesspaces –– PrimaryPrimary blastblast injuryinjury (pressure-related(pressure-related effects)effects) predominatepredominate overover bluntblunt traumatrauma “ABC” evaluation for life threatening injuries No obvious injuries Obvious Injuries Otoscopic Exam + - Observe - O2 Sat 6-8 hours Treat Injuries as usual Release + + - Injury RX and blast observation D/C with (pulmonary/visceral) Admit Abd Warnings Triage Algorithm Blast Injuries: DePalma, Burris et al NEJM 2005: 352: 1335-1342 PrimaryPrimary BlastBlast InjuriesInjuries •• OccursOccurs mostmost frequentlyfrequently in:in: –– MiddleMiddle earear –– LungsLungs –– LargeLarge BowelBowel •• ResultsResults from:from: –– BlastBlast wavewave contactcontact (dynamic(dynamic pressurepressure changes)changes) atat air-waterair-water interfacesinterfaces –– BlastBlast loadingloading •• HighHigh frequencyfrequency stressstress wavewave •• LowLow frequencyfrequency shearshear wavewave ** PrimaryPrimary blastblast injuriesinjuries occuroccur mostmost frequentlyfrequently inin air-filledair-filled organs,organs, andand resultsresults fromfrom blastblast wavewave dynamicdynamic pressurepressure changeschanges atat air-air- fluidfluid interfacesinterfaces PrimaryPrimary BlastBlast InjuriesInjuries •• EarEar –– TMTM rupturesruptures atat 1-81-8 psipsi dynamicdynamic overpressureoverpressure –– TemporaryTemporary neuropraxianeuropraxia ofof receptorreceptor organsorgans –– DislodgementDislodgement ofof ossiclesossicles maymay occuroccur •• LungLung –– PulmonaryPulmonary contusionscontusions –– multifocal multifocal hemorrhageshemorrhages –– PulmonaryPulmonary C-fiberC-fiber receptorreceptor injuryinjury causescauses vagalvagal nerve-mediatednerve-mediated cardiogeniccardiogenic shockshock –– OtherOther injuries:injuries: hemothoraces,hemothoraces, pneumothoraces,pneumothoraces, traumatictraumatic emphysema,emphysema, AVAV fistuale,fistuale, pulmonarypulmonary barotrauma,barotrauma, venousvenous airair emboliemboli PrimaryPrimary BlastBlast InjuriesInjuries •• GastrointestinalGastrointestinal TractTract –– PrimarilyPrimarily inin coloncolon –– RuptureRupture •• UsuallyUsually acutelyacutely •• DelayedDelayed duedue toto ischemiaischemia –– TensionTension pneumoperitoneumpneumoperitoneum –– SolidSolid organorgan subcapsularsubcapsular petechiaepetechiae •• Head/NeckHead/Neck –– ConcussionConcussion Secondary/TertiarySecondary/Tertiary BlastBlast InjuriesInjuries FragmentsFragments New Wounds to New Surgeons Blast & CCC - Burris Vietnam - Same as today CrushCrush SyndromeSyndrome •• AA conditioncondition resultingresulting fromfrom damagedamage toto thethe renalrenal tubules tubules inin kidneyskidneys following following severesevere injuryinjury toto musclemuscle tissue tissue in in crushingcrushing accidents.accidents. •• EdemaEdema •• OliguriaOliguria •• CKCK >> 25,00025,000 CompartmentCompartment SyndromeSyndrome •• PerfusionPerfusion pressurepressure << tissuetissue pressurepressure inin aa closedclosed anatomicanatomic space.space. •• LeftLeft untreated:untreated: –– TissueTissue necrosisnecrosis –– FunctionalFunctional impairmentimpairment –– RenalRenal failurefailure –– DeathDeath •• Sites:Sites: hand,hand, forearm,forearm, upperupper arm,arm, abdomen,abdomen, buttock,buttock, andand entireentire lowerlower extremity.extremity. CompartmentCompartment SyndromeSyndrome •• 69%69% associatedassociated withwith fracturefracture •• 11stst signs:signs: painpain onon passivepassive movementmovement andand swellingswelling •• Diagnosis:Diagnosis: 55 PsPs –– Pain,Pain, paresthesia,paresthesia, pallor,pallor, poikilothermia,poikilothermia, pulselessnesspulselessness •• Treatment:Treatment: –– ElevationElevation –– FasciotomyFasciotomy –– Mannitol?Mannitol? –– HBO?HBO? TREATMENTTREATMENT PRIORITIESPRIORITIES On-siteOn-site considerationsconsiderations •• ImpalementImpalement –– PenetrationPenetration byby flyingflying objectsobjects andand fragmentsfragments –– Don’tDon’t removeremove –– CoverCover and,and, ifif possible,possible, stabilizestabilize inin situsitu toto preventprevent worseningworsening damagedamage •• BurnsBurns –– cover cover (relatively(relatively cleanclean materials)materials) –– ToTo preventprevent furtherfurther grossgross contaminationcontamination –– ToTo preventprevent heatheat lossloss •• TransportationTransportation // fracturesfractures –– ConsiderConsider splintingsplinting long-bonelong-bone fracturesfractures DiagnosisDiagnosis PhysicalPhysical examinationexamination •• FrothyFrothy sputumsputum •• EarlyEarly pulmonarypulmonary edemaedema fromfrom primaryprimary blastblast injuryinjury grimgrim prognosis,prognosis, maymay bebe triagetriage marker,marker, thethe earlierearlier itit happenshappens thethe worseworse thethe prognosisprognosis •• TympanicTympanic MembraneMembrane •• MarkerMarker forfor blastblast overpressureoverpressure •• InIn thethe absenceabsence ofof aa rupturedruptured TM,TM, thethe riskrisk ofof hollowhollow viscousviscous injuryinjury isis lowlow •• FragmentFragment woundswounds •• smallsmall externalexternal woundswounds maymay maskmask significantsignificant internalinternal damagedamage •• SignsSigns ofof internalinternal bleedingbleeding TreatmentTreatment ConsiderationsConsiderations •• UsualUsual surgicalsurgical approachesapproaches forfor traumatrauma •• ObservationObservation forfor pulmonarypulmonary blastblast injuryinjury –– TMTM rupturerupture aa markermarker –– FollowFollow O2O2 SatSat forfor 6-86-8 hourshours •• PulmonaryPulmonary blastblast injuryinjury –– LimitLimit fluidsfluids –– VentilatorVentilator supportsupport withwith limitedlimited inspiratoryinspiratory pressurepressure andand PEEP.PEEP. TreatmentTreatment ConsiderationsConsiderations •• HollowHollow viscusviscus injuryinjury –– PresentationPresentation maymay bebe delayeddelayed