职业环境与健康8年制gas poisoning 2017

OccupationalEnvironmentandHealth(GasPoisoning)AssociateProf.QingWangSchoolofPublicHealthSunYat-senUniversity

Oct16th,20172Gaspoisoning

irritantgases

Chlorine,Oxynitride

asphyxiatinggases

CO,Cyanide

Whatwillbecovered?3InDecember1984,Agasleak

incidentin

India,considered

theworld‘sworst

industrialdisaster.Over500,000peoplewereexposedto

methylisocyanate

gas异氰酸甲脂.Thegovernmentconfirmedatotalof3,787deaths.Theleakcaused558,125injuriesincluding38,478temporarypartialinjuriesandapproximately3,900severelyandpermanentlydisablinginjuries.Bhopal（博帕尔）gastragedyThecombustiblegasleakoutandexplodeatthe4thPlasticManufactureofNanjingin2010TheexplosivegaseruptioninMexicobayin2010ThechlorineleakageinNantongchloridemanufacturein2010Liquefied

gastruck

rolloverinZhengzhou2007,10,000peopleevacuate6ChemicalweaponsinthewarfareWorldwarI☼1914:Teargasethylbromoacetate

（溴乙酸乙酯）☼1915:Teargasxylylbromide（甲苄基溴）Chorine;phosgene☼1917:Mustardgas(二氯乙基硫）

WorldwarII☼Chorine,phosgene,mustardgas☼Sarin;Soman(甲氟磷酸异已酯);TabunIrritantgasesDefinition：Irritantgasesarechemicalscapableofcausinginflammationofthemucousmembranesoftheeyes,nose,throat,andlungsatrelativelylowconcentrations,usuallyduetothereleaseofacidicoralkalineradicals.8High-ammonia-chloramine-hydrogenchloride-sulfurdioxideMod.-chlorineLow-formaldehyde-phosgene-nitrogendioxide

IrritantgasesVaryaccordingtowatersolubilityFactorsinfluencingirritantgaspoisoning9HighlysolublegasesAbsorbedbyupperrespiratorytractCausecoughing,wheeze（喘息）,sorethroat（咽喉溃烂）,laryngospasm,conjunctivitis（结膜炎）immediatelyCancauseedema→airwayobstructionLowsolubilityInhaledintolowerrespiratorytractCausechemicalpneumonitisanddelayedonsetpulmonaryedema(12-24hourspostexposure)10OtherfactorsdeterminingtheeofexposureExposurelevelExposuredurationSpeedofabsorptionToxicpulmonaryedemaDefinition:Toxicpulmonaryedema,alsonamedaschemicalpneumonedema,isadiseasethatfluidaccumulationoccursinthetissueandairspacesofthelungscausedbychemicals.12IncreasedcapillaryhydrostaticpressureIncreasedcapillarypermeability3.Releaseofvascularcytokines4.LymphaticobstructionMechanismofchemicalpneumonedemaToomuchliquidaccumulatesinthepulmonaryalveolarcavity13Rapidonsetofsymptoms(secondstominutes)Oral,nasalandpharyngealpainMucosaledema,cough,stridor

（喘鸣音）Conjunctivitis,chemosis,skinirritationGaseswithgoodwatersolubilitycausesupperairwayobstructionClinicalmanifestations

Acute

poisoning

14GaseswithoutrapidonsetofmanifestationEntryintolowerrespiratorytractTracheobronchitis,Acutelunginjury,non-cardiogenicpulmonaryedemaDyspnea,chesttightness,cough,frothy

sputum

粉红色泡沫样痰,wheezing,crackle

X-ray:alveolarinfiltrationArterialhypoxemia

Prolongedexposure15Developmentofchemical

pneumonedemaStageI--Irritation:cough,shortnessofbreath,chestpain,burningsensationinthethroatandsubsternal

area,nauseaorvomiting,etc.StageII--Latency:symptomsorsignsarealleviativeordisappear,2~12h16StageIII--Edema:tachypnea,nasalflaring,severecough,wetrhonchi,pinkfrothysputum,nauseaorvomiting,anxious,lowbloodpressure,hypoxia,acuterespiratorydistresssyndrome(ARDS)Developmentofchemical

pneumonedema(cont’)17StageIII

X-ray:hazinessofhilarshadows,alveolaredemawithpleuraleffusionsandbilateralinfiltratesinabutterflypattern.两肺广泛分布的片絮状阴影，有时候可融合成大片状或呈蝴蝶状分布。18WhatisARDS?

AcuteRespiratoryDistressSyndromeAcuteLungInjury150–200mmHg<PaO2/FIO2<250–300mmHgARDSPaO2/FIO2

<150–200mmHg，respiratoryrate>28t/mAcutedyspnea/tachypnearhonchi/wheezinghypoxemiaX-raydiffuse,bilateralinfiltratesOxygenationindex=PaO2(partialpressureofoxygeninarterialblood）/FIO2(fractionofinspirationofO2

)19Developmentofchemical

pneumonedema(cont’)StageIV—Recovery:

After

3-4daysofpropertreatment,thesymptomsandsignswillalleviate.Thepatientsusuallyrecoverafter7-11daysoftreatment.Clinicalmanifestations

Chronic

poisoning（rare）

Long-termexposuretolowconcentrationsofirritatinggasescancause:(1)chronicconjunctivitis,rhinitis,pharyngitis,bronchitisandtoothacidosis.(2)neurologicalandgastrointestinalsymptoms.(3)acutechlorinepoisoningcanbeleftafterchronicasthmaticbronchitis.(4)bronchialasthma.21Diagnosis(GBZ73-2002)ExposurehistoryTypicalsymptomsandsignsExamination:X-Ray,arterialbloodgasesanalysis5.Grading---Irritantresponse---Mildpoisoning---Moderatepoisoning---Severepoisoning22DiagnosisgradingModerate:withoneofthefollowingmanifestations:Shortnessofbreath,cough,productivecough,choking,slightcyanosis,X-raypresentingbronchialpneumonitisfeatures.Cough,productivecough,decreasedbreathsounds,severeshortnessofbreath,X-raypresentinginterstitialpneumoedema

features.Cough,productivecough,shortnessofbreath,wetrhonchi,X-raypresentingacutelimitedalveolaredema

features.23Severe:withoneofthefollowingmanifestations:Severecough,whiteorpinkfrothysputum,dyspnea,obviouscyanosis（发绀）,bilateralwetrhonchi,X-raypresentingthefeaturesofcentralalveolaredema.Arterialbloodgasesanalysis:PaO2/FiO240kPa(300mmHg)Lowbreathrate,panyingwithrespiratorydistress,X-raypresentingfeaturesofARDS,PaO2/FiO226.7kPa(200mmHg)AsphyxiaPneumothorax（气胸）,emphysema（肺气肿）,cardiomyopathy5.Suddendeath24TreatmentEmergencymanipulation

Removetheindividualfromthetoxicenvironment

EyeandskinexposuresrequirecopiousirrigationwithsalineTreatcornealabrasionswithantibioticointment

SupplementaloxygenTreatmentofbronchospasm（支气管痉挛）Intubationforlaryngospasm

25Treatment(cont’)Preventionofpneumoedema:earlieradministrationofsteroids,activityrestrictionAvoidexcessivefluidadministration4%sodiumbicarbonateor2%boricacid硼酸asantidote26TreatmentofpneumoedemaandARDS

MaintainaPaO2of60mmHgorgreaterAdministrationof1%Dimethiconum二甲基硅油

—reducefrothSteroids:dexamethasoneControlofinfectionBalanceofelectrolyte27ChlorineExposure:mixinghypochlorite

withacid（洁厕精与巴氏消毒液不能混用）,agedhypochloritetablet,compressedchlorinegasforwaterchlorinationDissolution:HypochlorousacidMildinitialupperrespiratorysymptomsDelayedsymptomsoflowerrespiratorytractinjuryforhoursCommonirritantgases28PhosgeneColorlessgas,heavierthanair,musty

odorExposure:combustionproductsofpolyvinyl（聚乙酸盐）orisocyanate

compounds（异氰酸盐）,chemicalwarfareProlongedexposureinduceupperandlowerrespiratorytractirritationDelayednon-cardiogenicpulmonaryedemaupto72hours29Nitrogendioxide(NO2)Reddish-browncolor,waterinsoluble,heavierthanairExposure:combustionofnitrocelluloseinfilmsandbedmattress,airpollutantMildupperairwayirritationDissolutionintonitrousacidsinbronchiole,terminalbronchioleandalveoliAcutenon-cardiogenicpulmonaryedema30Ammonia(NH3)Highlywater-soluble,colorlesswithauniquepungentodor

Exposure:ammonialeaksinfertilizertanksandhoses,animalfeedconfinementbuildings,householdcleaningproductsReactswithwatertoformthestronglyalkalinesolution,ammoniumhydroxide(NH4OH)Severealkalinechemicalburnsoccur,respiratorytractobstructionNon-cardiogenicpulmonaryedema,ARDS31Summary

Irritantgasesusuallyhaveauniquepungentodor

ArterialhypoxemiaisakeyphysiologicalchangeTheclinicalmanifestationsvariesaccordingtowatersolubility-Gaseswithgoodwatersolubility

causesupperairwayobstruction-GaseswithlowsolubilityoftencausechemicalpneumonitisanddelayedonsetpulmonaryedemaX-Ray,arterialbloodgasesanalysisareimportanttomakeadiagnosis32AsphyxiatinggasesSimpleasphyxiants:decreaseFiO2bydisplacingoxygenininspiredair,resultsinhypoxemia,suchasN2,CH3,CO2,etcChemicalasphyxiants:interferewithoxygentransportsystemandcellularrespirationandtherebycausetissuehypoxia,suchasCO,H2S,HCNDefinitionandclassification:33CO-Thesilent,coldweatherkillerCarbonmonoxide(CO)isanodorless,tasteless,andcolorlessgasHighlevelscankillwhilefamilymembersareasleepCOoftenstrikesincoldweatherwhenheatingequipmentoperates,andwhenwindowsanddoorsareclosed34SourcesofexposureOccupationalexposuresandfiresarethemostcommonsourcesofinhalationinjuries,especiallyworkinginconfinedspaces.pletecombustionofsolid,liquidorgaseousfuelsReleasedwithburningofanycarbonmaterial,kerosene（煤油）,naturalgas,oil,gasolineMotorvehicleexhaust35MechanismofpoisoningBindstoHbwith200timesmoreaffinitivethanO2

DissociationforceofHbCOis3600timeslowerthanHbO2

,resultinginimpairedreleaseofoxygenattissuelevelBindstocytc,resultinginfunctionaldefectofmitochondria

36ClinicalmanifestationsAcutepoisoning:hypoxia-induced

Generalheadache,nausea,vomiting,weakness(Flu-likeSymptoms)Cardiovascularchestpain,tachypnea,tachycardia,hypotensionpulmonaryedema,arrhythmias,cardiacarrestNeurologicdizziness,ataxia,seizures（癫痫）,comaOthersretinalhemorrhages（视网膜出血）,metabolicacidosis37SeverityofCOintoxicationInhaledCOconcentrationDurationofexposureIndividualsusceptibilityPresenceofsystemicillnessescardiacandpulmonarydiseases38DelayedorpersistentCOtoxicityPersistent:presentfromexposureDelayed:2to40dayspost-exposureDementia,psychosis,memorydeficitParkinsonism,paralysis,chorea（舞蹈症）Personnalitychanges,gaitdisturbanceCorticalblindness,agnosia（失忆症）Peripheralneuropathy,urinaryincontinence（尿失禁）39DiagnosisGradingExposureresponseMildpoisoningModeratepoisoningSeverepoisoninghydrocephalus,pneumoedema,respiratoryfailure碳氧血红蛋白40RemovetheindividualfromthetoxicenvironmentVentilation,keepwarm

100%oxygenadministration,hyperbaricoxygen(inspecialcases)

MonitoringofECG,electrolytesandarterialbloodgasesSupportivetherapyPreventionofhydrocephalus脑水肿,pneumoedema,respiratoryfailureTreatment41PreventionofCOpoisoningPubliceducationaboutCOpoisoningIdentificationofactivitiesatriskAppropriateventilationofconfinedplacesIndustrialanddomesticuseofCOdetectorsReportingtopublichealthservices42Summary

Themostcommoncauseofchemicalintoxicationinindustry

ManyhouseholdappliancesproduceCO

Bindstohemoglobinandformscarboxyhemoglobin,leadtohypoxemia

EarlysymptomsofCOareoftenliketheflu

Prevention:install,use,andmaintainappliancesproperly43Cyanides-OverviewHCN

HighlyvolatileEasilydispersedasaerosolsReadilysolubleandstableinwaterMajorrouteoftoxicityisinhalationAromaofbitteralmonds44Sourcesofexposure

EmissionsfromironandsteelproductionBurningofcoalPetroleumrefineriesProductionofsyntheticfiberandpesticidesProductionofplastics,pigments,anddyesSuicideorintentionalpoisoning45Mechanismofcyanide-toxicityCN-bindstocytochromea-a3andinhibitsoxydativephosphorylatione:cellularasphyxia,decreasedtissueoxygenutilization,venousO2,ruddinessinskinandmucosa.46StopsaerobicmetabolismLacticacidaccumulatesandcellsdiefromahistotoxicanoxiaAlterscalciummetabolismMechanismofcyanide-toxicity(Cont’)47Cyanides-highlytoxicchemicalsLowconcentration(50ppmorless):anxiety,restlessness,dyspnea,palpitation,headacheHigherconcentration(100ppm):

deathin30minute,tachycardia,tachypnea,syncope,seizuresHighdose(250ppm):

immediateonset:seizures,bradycardia

orasystole,respiratorydepression,coma,electroshock-likedeath48SignsandSymptomsAcutepoisoning:StageI

Preceding:eye,throat,orupperrespiratorystimulation,bitteralmondodoronthebreath,nausea,vomitingStageII

Dyspnea:severedyspnea,unstablebreathfrequency,fear,orreductioninhearingandvision,ruddyskinandmucosa.StageIIISpasm:entasia强直性痉挛,intermittentclonus抽筋,lowbloodpressure,lossofreflections49SignsandSymptoms(cont’)StageIV

Paralysis:muscularlaxation,lossofallreflections,