Cardiac arrest - Wikipedia

CardiacarrestSynonymsCardiopulmonaryarrest,circulatoryarrest,suddencardiacarrest(SCA),suddencardiacdeath(SCD)[1]CPRbeingadministeredduringasimulationofcardiacarrest.SpecialtyCardiologySymptomsLossofconsciousness,abnormalornobreathing[1][2]UsualonsetOlderage[3]CausesCoronaryarterydisease,majorbloodloss,lackofoxygen,verylowpotassium,heartfailure[4]DiagnosticmethodFindingnopulse[1]PreventionNotsmoking,physicalactivity,maintainingahealthyweight[5]TreatmentCardiopulmonaryresuscitation(CPR),defibrillation[6]PrognosisAveragesurvival8%[7]Frequency13per10,000peopleperyear(outsideofhospitalintheUSA)[8]CardiacarrestFromWikipedia,thefreeencyclopediaCardiacarrestisasuddenstopineffectivebloodflowduetothefailureofthehearttocontracteffectively.[9]Symptomsincludelossofconsciousnessandabnormalorabsentbreathing.[1][2]Somepeoplemayhavechestpain,shortnessofbreath,ornauseabeforethisoccurs.[2]Ifnottreatedwithinminutes,deathusuallyoccurs.[9]Themostcommoncauseofcardiacarrestiscoronaryarterydisease.Lesscommoncausesincludemajorbloodloss,lackofoxygen,verylowpotassium,heartfailure,andintensephysicalexercise.AnumberofinheriteddisordersmayalsoincreasetheriskincludinglongQTsyndrome.Theinitialheartrhythmismostoftenventricularfibrillation.[4]Thediagnosisisconfirmedbyfindingnopulse.[1]Whileacardiacarrestmaybecausedbyheartattackorheartfailure,thesearenotthesame.[9]Preventionincludesnotsmoking,physicalactivity,andmaintainingahealthyweight.[5]Treatmentforcardiacarrestisimmediatecardiopulmonaryresuscitation(CPR)and,ifashockablerhythmispresent,defibrillation.[6]Amongthosewhosurvivetargetedtemperaturemanagementmayimproveoutcomes.[10]Animplantablecardiacdefibrillatormaybeplacedtoreducethechanceofdeathfromrecurrence.[5]IntheUnitedStates,cardiacarrestoutsideofhospitaloccursinabout13per10,000peopleperyear(326,000cases).Inhospitalcardiacarrestoccursinanadditional209,000.[8]Cardiacarrestbecomesmorecommonwithage.Itaffectsmalesmoreoftenthanfemales.[3]Thepercentageofpeoplewhosurvivewithtreatmentisabout8%.Manywhosurvivehavesignificantdisability.ManyU.S.televisionshows,however,haveportrayedunrealisticallyhighsurvivalratesof67%.[7]Contents1Signsandsymptoms2Causes2.1Coronaryarterydisease2.2Non-ischemicheartdisease2.3Non-cardiaccauses2.3Non-cardiaccauses2.4Riskfactors2.5Mnemonicforcauses3Mechanism4Diagnosis4.1Classifications5Prevention5.1Codeteams5.2Implantablecardioverterdefibrillators5.3Diet6Management6.1Cardiopulmonaryresuscitation6.2Defibrillation6.3Medications6.4Targetedtemperaturemanagement6.5Donotresuscitate6.6Chainofsurvival6.7Other7Prognosis8Epidemiology9Names10References11ExternallinksSignsandsymptomsCardiacarrestissometimesprecededbycertainsymptomssuchasfainting,fatigue,blackouts,dizziness,chestpain,shortnessofbreath,weakness,andvomiting.[11]Thearrestmayalsooccurwithnowarning.Whenthearrestoccurs,themostobvioussignofitsoccurrencewillbethelackofapalpablepulseinthepersonexperiencingit(sincethehearthasceasedtocontract,theusualindicationsofitscontractionsuchasapulsewillnolongerbedetectable).Certaintypesofpromptinterventioncanoftenreverseacardiacarrest,butwithoutsuchinterventiontheeventwillalmostalwaysleadtodeath.[12]Incertaincases,itisanexpectedoutcomeofaseriousillnesswheredeathisexpected.[13]Also,asaresultofinadequatecerebralperfusion,thepatientwillquicklybecomeunconsciousandwillhavestoppedbreathing.Themaindiagnosticcriteriontodiagnoseacardiacarrest(asopposedtorespiratoryarrestwhichsharesmanyofthesamefeatures)islackofcirculation;however,thereareanumberofwaysofdeterminingthis.Near-deathexperiencesarereportedby10–20%ofpeoplewhosurvivedcardiacarrest.[14]CausesCoronaryarterydiseaseistheleadingcauseofsuddencardiacarrest.Manyothercardiacandnon-cardiacconditionsalsoincreaseone'srisk.Coronaryarterydiseaseoftenresultsincoronaryischemiaandventricularfibrillation(v-fib).[15]CaseshaveshownthatthemostcommonfindingatpostmortemexaminationofSCDischronichigh-gradestenosisofatleastonesegmentofamajorcoronaryartery,[16]thearteriesthatsupplytheheartmusclewithitsbloodsupply.Leftventricularhypertrophyisthoughttobetheleadingcauseofsuddencardiacdeathintheadultpopulation.[17]Thisismostcommonlytheresultoflongstandinghighbloodpressurewhichhascausedsecondarydamagetothewallofthemainpumpingchamberoftheheart,theleftventricle.[18]Althoughthemostfrequentcauseofsuddencardiacdeathisventricularfibrillation,othercausesincludethefollowing:[19]CoronaryheartdiseasePhysicalstresslowlevelsofmagnesiumlowlevelsofpotassiummajorbloodlosslackofoxygenseverephysicalactivitywhichtriggersadrenalineInheriteddisordersHypertrophiccardiomyopathyEnlargedheartduetoincreasedbloodpressureCommotiocordisCoronaryarterydiseaseApproximately60–70%ofSCDisrelatedtocoronaryarterydisease,alsoknownasischemicheartdisease.[20][21]Amongadults,itisthepredominantcauseofarrest,[22]with30%ofpeopleatautopsyshowingsignsofrecentmyocardialinfarction.Non-ischemicheartdiseaseAnumberofnon-ischemiccardiacabnormalitiescanincreasetheriskofSCD,includingcardiomyopathy,cardiacrhythmdisturbances,myocarditis,hypertensiveheartdisease,[20]andcongestiveheartfailure.[23]Inagroupofmilitaryrecruitsaged18–35,cardiacanomaliesaccountedfor51%ofcasesofSCD,whilein35%ofcasesthecauseremainedunknown.Underlyingpathologyincludedcoronaryarteryabnormalities(61%),myocarditis(20%),andhypertrophiccardiomyopathy(13%).[24]CongestiveheartfailureincreasestheriskofSCDfivefold.[23]Manyadditionalconductionabnormalitiesexistthatplaceoneathigherriskforcardiacarrest.Forinstance,longQTsyndrome,aconditionoftenmentionedinyoungpeople'sdeaths,occursinoneofevery5000to7000newbornsandisestimatedtoberesponsiblefor3000deathseachyearcomparedtotheapproximately300,000[25]cardiacarrestsseenbyemergencyservices.Theseconditionsareafractionoftheoveralldeathsrelatedtocardiacarrest,butrepresentconditionswhichmaybedetectedpriortoarrestandmaybetreatable.Non-cardiaccausesAbout35%ofSCDsarenotcausedbyaheartcondition.Themostcommonnon-cardiaccausesaretrauma,bleeding(suchasgastrointestinalbleeding,aorticrupture,orintracranialhemorrhage),overdose,drowningandpulmonaryembolism.[26]Cardiacarrestcanalsobecausedbypoisoning(forexample,bythestingsofcertainjellyfish).RiskfactorsTheriskfactorsforSCDaresimilartothoseofcoronaryarterydiseaseandincludesmoking,lackofphysicalexercise,obesity,anddiabetes,aswellasfamilyhistory.[27]Apriorepisodeofsuddencardiacarrestalsoincreasestheriskoffutureepisodes.Mnemonicforcauses"HsandTs"isthenameforamnemonicusedtoaidinrememberingthepossibletreatableorreversiblecausesofcardiacarrest.[28][29]HsHypovolemia-AlackofbloodvolumeHypoxia-AlackofoxygenHydrogenions(Acidosis)-AnabnormalpHinthebodyHyperkalemiaorHypokalemia-Bothexcessandinadequatepotassiumcanbelife-threatening.Hypothermia-AlowcorebodytemperatureHypoglycemiaorHyperglycemia-LoworhighbloodglucoseTsTabletsorToxinsCardiacTamponade-FluidbuildingaroundtheheartTensionpneumothorax-AcollapsedlungThrombosis(Myocardialinfarction)-HeartattackThromboembolism(Pulmonaryembolism)-AbloodclotinthelungTraumaticcardiacarrestMechanismThemechanismofdeathinthemajorityofpeopledyingofsuddencardiacdeathisventricularfibrillation.[4]Structuralchangesinthediseasedheartasaresultofinheritedfactors(mutationsinion-channelcodinggenesforexample)cannotexplainthesuddennessofSCD.[30]Also,suddencardiacdeathcouldbetheconsequenceofelectric-mechanicaldisjunctionandbradyarrhythmias.[31][32]DiagnosisVentricularfibrillationCardiacarrestissynonymouswithclinicaldeath.Acardiacarrestisusuallydiagnosedclinicallybytheabsenceofapulse.Inmanycaseslackofcarotidpulseisthegoldstandardfordiagnosingcardiacarrest,aslackofapulse(particularlyintheperipheralpulses)mayresultfromotherconditions(e.g.shock),orsimplyanerroronthepartoftherescuer.Nonetheless,studieshaveshownthatrescuersoftenmakeamistakewhencheckingthecarotidpulseinanemergency,whethertheyarehealthcareprofessionals[33]orlaypersons.[34]Owingtotheinaccuracyinthismethodofdiagnosis,somebodiessuchastheEuropeanResuscitationCouncil(ERC)havede-emphasiseditsimportance.TheResuscitationCouncil(UK),inlinewiththeERC'srecommendationsandthoseoftheAmericanHeartAssociation,[29]havesuggestedthatthetechniqueshouldbeusedonlybyhealthcareprofessionalswithspecifictrainingandexpertise,andeventhenthatitshouldbeviewedinconjunctionwithotherindicatorssuchasagonalrespiration.[28]Variousothermethodsfordetectingcirculationhavebeenproposed.Guidelinesfollowingthe2000InternationalLiaisonCommitteeonResuscitation(ILCOR)recommendationswereforrescuerstolookfor"signsofcirculation",butnotspecificallythepulse.[29]Thesesignsincludedcoughing,gasping,colour,twitchingandmovement.[35]However,infaceofevidencethattheseguidelineswereineffective,thecurrentrecommendationofILCORisthatcardiacarrestshouldbediagnosedinallcasualtieswhoareunconsciousandnotbreathingnormally.[29]Anothermethodistousemolecularautopsyorpostmortemmoleculartestingwhichusesasetofmoleculartechniquestofindtheionchannelsthatarecardiacdefective.ClassificationsCliniciansclassifycardiacarrestinto"shockable"versus"non–shockable",asdeterminedbytheECGrhythm.Thisreferstowhetheraparticularclassofcardiacdysrhythmiaistreatableusingdefibrillation.[28]Thetwo"shockable"rhythmsareventricularfibrillationandpulselessventriculartachycardiawhilethetwo"non–shockable"rhythmsareasystoleandpulselesselectricalactivity.[36]PreventionWithpositiveoutcomesfollowingcardiacarrestunlikely,anefforthasbeenspentinfindingeffectivestrategiestopreventcardiacarrest.Withtheprimecausesofcardiacarrestbeingischemicheartdisease,effortstopromoteahealthydiet,exercise,andsmokingcessationareimportant.Forpeopleatriskofheartdisease,measuressuchasbloodpressurecontrol,cholesterollowering,andothermedico-therapeuticinterventionsareused.[1]ACochranereviewpublishedin2016foundmoderate-qualityevidencetoshowthatbloodpressure-loweringdrugsdonotappeartoreducesuddencardiacdeath.[37]CodeteamsInmedicalparlance,cardiacarrestisreferredtoasa"code"ora"crash".Thistypicallyrefersto"codeblue"onthehospitalemergencycodes.Adramaticdropinvitalsignmeasurementsisreferredtoas"coding"or"crashing",thoughcodingisusuallyusedwhenitresultsincardiacarrest,whilecrashingmightnot.Treatmentforcardiacarrestissometimesreferredtoas"callingacode".Peopleingeneralwardsoftendeteriorateforseveralhoursorevendaysbeforeacardiacarrestoccurs.[28][38]Thishasbeenattributedtoalackofknowledgeandskillamongstward-basedstaff,inparticularafailuretocarryoutmeasurementoftherespiratoryrate,whichisoftenthemajorpredictorofadeterioration[28]andcanoftenchangeupto48hourspriortoacardiacarrest.Inresponsetothis,manyhospitalsnowhaveincreasedtrainingforward-basedstaff.Anumberof"earlywarning"systemsalsoexistwhichaimtoquantifytheriskwhichpatientsareatofdeteriorationbasedontheirvitalsignsandthusprovideaguidetostaff.Inaddition,specialiststaffarebeingutilisedmoreeffectivelyinordertoaugmenttheworkalreadybeingdoneatwardlevel.Theseinclude:Crashteams(orcodeteams)-Thesearedesignatedstaffmemberswithparticularexpertiseinresuscitationwhoarecalledtothesceneofallarrestswithinthehospital.Thisusuallyinvolvesaspecializedcartofequipment(includingdefibrillator)anddrugscalleda"crashcart"or"crashtrolley".Medicalemergencyteams-Theseteamsrespondtoallemergencies,withtheaimoftreatingthepeopleintheacutephaseoftheirillnessinordertopreventacardiacarrest.Theseteamshavebeenfoundtodecreasetheratesofinhospitalcardiacarrestandimprovesurvival.[8]Criticalcareoutreach-Aswellasprovidingtheservicesoftheothertwotypesofteam,theseteamsarealsoresponsibleforeducatingnon-specialiststaff.Inaddition,theyhelptofacilitatetransfersbetweenintensivecare/highdependencyunitsandthegeneralhospitalwards.Thisisparticularlyimportant,asmanystudieshaveshownthatasignificantpercentageofpatientsdischargedfromcriticalcareenvironmentsquicklydeteriorateandarere-admitted;theoutreachteamofferssupporttowardstafftopreventthisfromhappening.Insomemedicalfacilities,theresuscitationteammaypurposelyrespondslowlytoapersonincardiacarrest,apracticeknownas"slowcode",ormayfaketheresponsealtogetherforthesakeoftheperson'sfamily,apracticeknownas"showcode".[39]ThisisgenerallydoneforpeopleforwhomperformingCPRwillhavenomedicalbenefit.[40]Suchpracticesareethicallycontroversial,[41]andarebannedinsomejurisdictions.ImplantablecardioverterdefibrillatorsAtechnologicallybasedinterventiontopreventfurthercardiacarrestepisodesistheuseofanimplantablecardioverter-defibrillator(ICD).Thisdeviceisimplantedinthepatientandactsasaninstantdefibrillatorintheeventofarrhythmia.NotethatstandaloneICDsdonothaveanypacemakerfunctions,buttheycanbecombinedwithapacemaker,andmodernversionsalsohaveadvancedfeaturessuchasanti-tachycardicpacingaswellassynchronizedcardioversion.ArecentstudybyBirnieetal.attheUniversityofOttawaHeartInstitutehasdemonstratedthatICDsareunderusedinboththeUnitedStatesandCanada.[42]AnaccompanyingeditorialbySimpsonexploressomeoftheeconomic,geographic,socialandpoliticalreasonsforthis.[43]PatientswhoaremostlikelytobenefitfromtheplacementofanICDarethosewithsevereischemiccardiomyopathy(withsystolicejectionfractionslessthan30%)asdemonstratedbytheMADIT-IItrial.[44]DietMarine-derivedomega-3polyunsaturatedfattyacids(PUFAs)hasbeenpromotedforthepreventionofsuddencardiacdeathduetoitspostulatedabilitytolowertriglyceridelevels,preventarrhythmias,decreaseplateletaggregation,andlowerbloodpressure.[45]However,accordingtoarecentsystematicreview,omega-3PUFAsupplementationarenotbeenassociatedwithalowerriskofsuddencardiacdeath.[46]ManagementSuddencardiacarrestmaybetreatedviaattemptsatresuscitation.Thisisusuallycarriedoutbaseduponbasiclifesupport(BLS)/advancedcardiaclifesupport(ACLS),[29]pediatricadvancedlifesupport(PALS)[47]orneonatalresuscitationprogram(NRP)guidelines.CardiopulmonaryresuscitationCardiopulmonaryresuscitation(CPR)isakeypartofthemanagementofcardiacarrest.Itisrecommendedthatitbestartedassoonaspossibleandinterruptedaslittleaspossible.ThecomponentofCPRthatseemstomakethegreatestdifferenceinmostcasesisthechestcompressions.CorrectlyperformedbystanderCPRhasbeenshowntoincreasesurvival;however,itisperformedinlessthan30%ofoutofhospitalarrestsasof2007.[48]Ifhigh-qualityCPRhasnotresultedinreturnofspontaneouscirculationandtheperson'sheartrhythmisinasystole,discontinuingCPRandpronouncingtheperson'sdeathisreasonableafter20minutes.[49]Exceptionstothisincludethosewithhypothermiaorwhohavedrowned.[49]LongerdurationsofCPRmaybereasonableinthosewhohavecardiacarrestwhileinhospital.[50]BystanderCPR,bythelaypublic,beforethearrivalofEMSalsoimprovesoutcomes.[8]Eitherabagvalvemaskoranadvancedairwaymaybeusedtohelpwithbreathing.[51]HighlevelsofoxygenaregenerallygivenduringCPR.[51]Trachealintubationhasnotbeenfoundtoimprovesurvivalratesincardiacarrest[48]andintheprehospitalenvironmentmayworsenit.[52]WhendonebyEMS30compressionsfollowedbytwobreathsappearbetterthancontinuouschestcompressionsandbreathsbeinggivenwellcompressionsareongoing.[53]Forbystanders,CPRwhichinvolvesonlychestcompressionsresultsinbetteroutcomesascomparedtostandardCPRforthosewhohavegoneintocardiacarrestduetoheartissues.[53]Mechanicalchestcompressions(asperformedbyamachine)arenobetterthanchestcompressionsperformedbyhand.[51]ItisunclearifafewminutesofCPRbeforedefibrillationresultsindifferentoutcomesthanimmediatedefibrillation.[54]Ifcardiacarrestoccursafter20weeksofpregnancysomeoneshouldpullorpushtheuterustotheleftduringCPR.[55]IfapulsehasnotreturnedbyfourminutesemergencyCesareansectionisrecommended.[55]DefibrillationDefibrillationisindicatedifashockablerhythmispresent.Thetwoshockablerhythmsareventricularfibrillationandpulselessventriculartachycardia.Inchildren2to4J/Kgisrecommended.[56]Inaddition,thereisincreasinguseofpublicaccessdefibrillation.Thisinvolvesplacingautomatedexternaldefibrillatorsinpublicplaces,andtrainingstaffintheseareashowtousethem.Thisallowsdefibrillationtotakeplacepriortothearrivalofemergencyservices,andhasbeenshowntoleadtoincreasedchancesofsurvival.SomedefibrillatorsevenprovidefeedbackonthequalityofCPRcompressions,encouragingthelayrescuertopressthepatient'schesthardenoughtocirculateblood.[57]Inaddition,ithasbeenshownthatthosewhohavearrestsinremotelocationshaveworseoutcomesfollowingcardiacarrest.[58]MedicationsMedications,whileincludedinguidelines,havenotbeenshowntoimprovesurvivaltohospitaldischargefollowingout-of-hospitalcardiacarrest.Thisincludestheuseofepinephrine,atropine,lidocaine,andamiodarone.[59][60][61]Epinephrineisgenerallyrecommendedeveryfiveminutes.[51]Vasopressinoveralldoesnotimproveorworsenoutcomescomparedtoepinephrine.[51]LipidemulsionasusedincardiacarrestduetolocalanestheticagentsEpinephrinedoesappeartoimproveshort-termoutcomessuchasreturnofspontaneouscirculation.[62]Someofthelackoflong-termbenefitmayberelatedtodelaysinepinephrineuse.[63]Whileevidencedoesnotsupportitsuseinchildrenguidelinesstateitsuseisreasonable.[56]Lidocaineandamiodaronearealsodeemedreasonableinchildrenwithcardiacarrestwhohaveashockablerhythm.[51][56]Thegeneraluseofsodiumbicarbonateorcalciumisnotrecommended.[51][64]The2010guidelinesfromtheAmericanHeartAssociationnolongercontaintherecommendationforusingatropineinpulselesselectricalactivityandasystoleduetothelackofevidenceforitsuse.[65]Neitherlidocainenoramiodarone,inthosewhocontinueinventriculartachycardiaorventricularfibrillationdespitedefibrillation,improvessurvivaltohospitaldischargebutbothequallyimprovesurvivaltohospitaladmission.[66]Thrombolyticswhenusedgenerallymaycauseharmbutmaybeofbenefitinthosewithaconfirmedpulmonaryembolismasthecauseofarrest.[67][55]Evidenceforuseofnaloxoneinthosewithcardiacarrestduetoopioidsisunclearbutitmaystillbeused.[55]Inthosewithcardiacarrestduetolocalanestheticlipidemulsionmaybeused.[55]TargetedtemperaturemanagementCoolingadultsaftercardiacarrestwhohaveareturnofspontaneouscirculation(ROSC)butnoreturnofconsciousnessimprovesoutcomes.[68][69]Thisprocedureiscalledtargetedtemperaturemanagement(previouslyknownastherapeutichypothermia).Peoplearetypicallycooledfora24-hourperiod,withatargettemperatureof32–36°C(90–97°F).[51]Deathratesinthehypothermiagroupare30%lowerthaninthosewithnotemperaturemanagement.[70]Longtermoutcomesarealsoimproved.[70]Complicationsaregenerallynogreaterinthosewhoreceivethistherapy.[68][71]Earlierversuslatercoolingmayresultinbetteroutcomes.[72]Atrialthatcooledintheambulance,however,foundnodifferencecomparedtostartingcoolingin-hospital.[72]Aregistrydatabasefoundpoorneurologicaloutcomeincreasedby8%witheachfive-minutedelayininitiatingTHandby17%forevery30-minutedelayintimetotargettemperature.[73]Inchildrenitisunclearifcoolingisbeneficialhoweverfevershouldbeprevented.[56]DonotresuscitateSomepeoplechoosetoavoidaggressivemeasuresattheendoflife.Adonotresuscitateorder(DNR)intheformofanadvancehealthcaredirectivemakesitclearthatintheeventofcardiacarrest,thepersondoesnotwishtoreceivecardiopulmonaryresuscitation.[74]Otherdirectivesmaybemadetostipulatethedesireforintubationintheeventofrespiratoryfailureor,ifcomfortmeasuresareallthataredesired,bystipulatingthathealthcareprovidersshould"allownaturaldeath".[75]ChainofsurvivalSeveralorganizationspromotetheideaofachainofsurvival.Thechainconsistsofthefollowing"links":Earlyrecognition-Ifpossible,recognitionofillnessbeforethepatientdevelopsacardiacarrestwillallowtherescuertopreventitsoccurrence.Earlyrecognitionthatacardiacarresthasoccurrediskeytosurvival-foreveryminuteapatientstaysincardiacarrest,theirchancesofsurvivaldropbyroughly10%.[28]EarlyCPR-improvestheflowofbloodandofoxygentovitalorgans,anessentialcomponentoftreatingacardiacarrest.Inparticular,bykeepingthebrainsuppliedwithoxygenatedblood,chancesofneurologicaldamagearedecreased.Earlydefibrillation-iseffectiveforthemanagementofventricularfibrillationandpulselessventriculartachycardia[28]EarlyadvancedcareEarlypost-resuscitationcarewhichmayincludepercutaneouscoronaryintervention[76]Ifoneormorelinksinthechainaremissingordelayed,thenthechancesofsurvivaldropsignificantly.Theseprotocolsareofteninitiatedbyacodeblue,whichusuallydenotesimpendingoracuteonsetofcardiacarrestorres