MyocardialInfarction心肌梗死

Myocardialinfarction心肌梗死Myocardialinfarction(MIorAMIforacutemyocardialinfarction),alsoknownasaheartattack心臟病發(fā)作,occurswhenthebloodsupplytopartoftheheartisinterrupted,resultingischemiaandoxygenshortage,ifleftuntreatedforasufficientperiod,cancausedamageand/ormyocardiuminfarction.Angina心絞痛asaresultofischemiacausesreversiblecellularinjury,andinfarctionistheresultofsustainedischemia,causingirreversiblecellulardeath.Classification分類Acutemyocardialinfarctionisatypeofacutecoronarysyndrome急性冠脈綜合征.Theacutecoronarysyndromesinclude:unstableangina(UA)不穩(wěn)定型心絞痛.STsegmentelevationmyocardialinfarction(STEMI)ST段抬高性心梗non-STsegmentelevationmyocardialinfarction(NSTEMI)非ST段抬高性心梗MyocardialinfarctionInfarctionsaredescribedbytheareaofoccurrenceasanterior前壁,posterior后壁,inferior下壁orlateral側(cè)壁wallinfarctions.InferiorMIisalsocalledadiaphragmaticMI(DMI)膈肌心梗Commoncombinationofareasaretheanterolateral前側(cè)壁心肌堵塞oranteroseptal(房室)隔前的MI.Pathophysiology病理生理Themostcommontriggeringeventisthedisruption破損ofanatheroscleroticplaque粥樣硬化斑塊inanepicardialcoronaryartery.Plaquescanbecomeunstable,rupture破裂,andadditionallypromoteathrombus血栓(bloodclot)thatoccludes阻塞theartery.Whenasevereenoughplaqueruptureoccursinthecoronaryvasculature,itleadstomyocardialinfarction.

Pathophysiology病理生理 Dependingonthelocationoftheobstructioninthecoronarycirculation,differentzonesoftheheartcanbecomeinjured.Anocclusionoftheleftanteriordescendingcoronaryartery(LAD)左冠狀動脈前降支willresultinananteriorwallmyocardialinfarct前壁心肌梗死.Infarctsofthelateralwall側(cè)壁心肌梗死arecausedbyocclusionoftheleftcircumflexcoronaryartery(LCx)冠狀動脈左盤旋支.Bothinferiorwallandposteriorwallinfarctions下壁和后壁心梗maybecausedbyocclusionofeithertherightcoronaryartery右冠狀動脈ortheleftcircumflexartery左冠狀動脈盤旋支,dependingonwhichfeedstheposteriordescendingartery.Rightventricularwallinfarcts右心室壁梗死arealsocausedbyrightcoronaryartery右冠狀動脈occlusion.Pathophysiology病理生理Thedegreeofpreestablishedcollateralcirculation側(cè)支循環(huán)提前建立alsodeterminetheseverityofinfarction.Inanindividualwithahistoryofheartdisease,adequatecollateralchannelsmayhavebeenestablishedthatprovidedtheareasurroundingtheinfarctionsitewithabloodsupplyandoxygen.ThisisoneexplanationwhytheyoungpersonwhohasasevereMIismorelikelytohaveamoreseriousimpairmentthananolderpersonwiththesamedegreeofocclusion.Healingprocess愈合過程Within24hours:Thebody’sresponsetocelldeathistheinflammationprocess.Leukocytes白細(xì)胞infiltratethearea.Enzymes酶arereleasedfromthedeathcardiaccellsandareimportantdiagnosticindicators.Healingprocess愈合過程Thesecondorthirdday:

Theproteolyticenzymes蛋白水解酶ofneutrophilsandmacrophages巨噬細(xì)胞removeallnecrotic壞死

tissueandthenecroticmusclewallisthin.Developmentofcollateralcirculationimprovetheareaofpoorperfusionandmaylimitthezonesofinjuryandinfarction.Onceinfarctiontakesplaces,catecholamine-mediated兒茶酚胺介導(dǎo)lipolysis脂解(作用)andglycogenolysis糖原分解

occur.Forthisreason,serumglucoselevelsarefrequentlyelevatedafterMIandmaybethereasonforapseudodiabeticstate假性糖尿病.Healingprocess愈合過程Within4to10days:

ThenecroticzoneisidentifiablebyECGchanges,atthispoint,thephagocytes(neutriphilsandmonocytes中性粒細(xì)胞和單核細(xì)胞)haveclearthenecroticdebirs壞死的碎片fromtheinjuryareaandthecollagenmatrix膠原基質(zhì)thatwilleventuallyformthescar瘢痕islaiddown.At10to14day:Thebeginningofscartissue疤痕組織isweak.Themyocardiumisconsideredtobeespeciallyvulnerabletoincreasedstressbecauseoftheunstablestateofthehealingheartwall.6weeksafterMI:

Scartissuehasreplacednecrotictissue,atthistime,theinjuredareaissaidtobehealed.

Clinicalmanifestation臨床表現(xiàn)PainSevere,immobilizingchestpainnotrelievedbyrestornitrateadministrationisthehallmarkofanMI.itisoftendescribedasasensationoftightness,pressure壓榨,orsqueezing緊縮.Commonlocationsaresubsternal胸骨下andretrosternal胸骨后.Painradiatesmostoftentotheleftarm,butmayalsoradiatetothelowerjaw下頜，

neck,rightarm,back,andepigastrium腹上部,whereitmaymimicheartburn.Painarecommonlyoccursintheearlymorninghours.Itusuallylastsfor20minutesormore.ClinicalmanifestationNauseaandvomitingNauseaandvomitingcanresultfromreflexstimulationofthevomitingcenterbytheseverpainandcanalsoresultfromvasovagalreflex血管迷走性反射fromtheareaoftheinfarctedmyocardium.Sympatheticstimulation

Diaphoresis發(fā)汗,weakness,light-headedness,andpalpitations心悸.Thesesymptomsarelikelyinducedbyamassivesurgeofcatecholamines兒茶酚氨fromthesympatheticnervoussystem

whichoccursinresponsetopainandthehemodynamicabnormalities血流動力學(xué)的異常thatresultfromcardiacdysfunction心功能不全.ClinicalmanifestationFeverThetemperaturemayincreasewithinthefirst24hourupto38to39.thetemperatureelevationmaylastsforaslongas1week.CardiovascularmanifestationsTheBPandpulseratemaybeelevatedinitially,laterBPmaydropbecauseofdecreasedCO.Urinemaybedecreased.Crackles濕啰音maybenotedinthelungs,persistingforseveralhourstodaysHepaticengorgement肝怒張andperipheraledema外周水腫mayindicatecovertcardiacfailure.Jugularveins

頸靜脈

maydistendedandmayhaveobviouspulsations搏動,indicatingearlyrightventriculardysfunctionandpulmonarycongestion.ComplicationDysrhythmias心律失常:arethemostcommoncomplication,presentin80%ofMIpatient.Theintrinsicrhythmoftheheartburnisdisrupted,causingeitherafastHR(tachycardia心動過速

),aslowHR(bradycardia心動過緩

),oranirregularbeat.Completeheartblock心臟傳導(dǎo)阻滯isseeninmassiveinfarction.Ventricularfibrillation室顫,acommoncauseofsuddendeath,isalethaldysrhythmiathatmostoftenoccurswithinthefirst4hoursaftertheonsetofpain.Prematureventricularcontractions室性早搏(PVCs)mayprecedeventriculartachycardia室性心動過速andfibrillation室顫.Ventriculardysrhythmianeedsimmediatetreatment.ComplicationCongestiveheartfailureCardiogenicshockPapillarymuscledysfunction乳頭肌功能障礙Ventricularaneurysm室壁瘤Pericarditis心包炎Dresslersyndrome德雷斯勒綜合征，心肌梗死后綜合征Pulmonaryembolism肺栓塞Diagnosticstudies輔助檢查ThreenoninvasivediagnosticparametersareusedtodeterminewhetherapersonhassustainedanacuteMI:Thepatient’shistoryofpain,riskfactorsandhealthhistory.12-leadECGconsistentwithacuteMI(inverted倒置Twaves,

ST-Twaveselevationsofgreaterthan1mmormoreintwocontiguousleads,abnormalQwave)MeasurementofserialmyocardialserumenzymesOthermeasuresincludes:ChestX-rayCBC,thyroidprofileNuclearimagingstudiesEndocardiogramDiagnosticstudiesECGfindingsECGareapproximately80%specificfordiagnosinganacuteMIandrepresentaleadingdiagnosticcriterion.Diagnosticstudies輔助檢查Cardiacenzymes:AnimportantdiagnosticcriterionforacuteMIislaboratoryassessmentofserialcardiacserumenzymes.Creatinekinase肌酸激酶(CK):CKlevelsbegintoriseapproximately6hoursafteranacuteMIandreturntonormalwithin2to3days.Lacticdehydrogenase乳酸脫氫酶(LDH)Aspartateaminotransferase谷草轉(zhuǎn)氨酶(AST)Therapeuticmanagement治療方案IVtherapy

InitialmanagementofMIisbestaccomplishedinacardiaccareunit(CCU),whereconstantmonitoringisavailable.AnIVrouteisestablishedtoprovideanaccessiblemeansforemergencydrugtherapy.Morphine嗎啡sulfatemaybegivenIV2-4mg/hrasneededforreliefofpain(ormeperidine

度冷丁ifpatientisallergictomorphine)AcontinuousIVinfusionoflidocaine

利多卡因maybegiven,prophylacticallytopreventventricularfibrillation室顫.Therapeuticmanagement治療方案OxygentherapyContinualECGmonitoringtodeterdysrhythmiasVitalsignsaretakenfrequentlyduringthefirstfewhoursafteradmissionandaremonitored1-4hrthereafter.Bedrestandlimitationactivityareusualinitially,withagradualincreaseinactivity.RecordingintakeandoutputApulmonaryartery(PA)catheter肺動脈導(dǎo)管andintraarterialline動脈內(nèi)置管maybeusedtoaccuratelymonitorintracardiac,pulmonaryartery,andsystolicarterialpressuresincomplicatedMIsothatthemosteffectivemodeoftreatmentintheacutephasecanbedetermined.Therapeuticmanagement

Thrombolytictherapy溶栓療法Itisnowknownthat80%to90%ofallacuteMIaresecondarytothrombusformation.ThrombolytictherapyisthestandardofpracticeinthetreatmentofacuteMI.Myocardialcellsdonodieinstantly.Ittakesapproximately4to6hoursforentirethicknessofthemuscletobecomenecrosedandthisisknownastransmuralinfarction跨壁梗死.TreatmentofacuteMIisgearedtoquicklydissolvingthrombusinthecoronaryarteryandreperfusingthemyocardiumbeforecellulardeathoccurs.Tobeofmostbenefit,thrombolyticsmustbegivenassoonaspossible,perferablywithinthefirst6hoursaftertheonsetofpain.Therapeuticmanagement

Thrombolytictherapy溶栓療法Thrombolyticagentsusedtotreatmyocardialinfarctionare:streptokinase(鏈激酶

),urokinase(尿激酶

),tissueplasminogenactivator(t-PA)(組織纖維蛋白溶酶原激活劑).Indicationsofthrombolytictherapy:ChestpaintypicalofacuteMIlessthanorequalto6hrinduration(somecentersextendthetimelimitto12hr).12-leadECGfindingsconsistentwithacuteMI.Thrombolytictherapy溶栓療法Contraindicationsofthrombolytictherapy:Absolutecontraindications禁忌:HistoryofhemorrhagicstrokeUncontrolledhypertension(SBP>200,DBP>120)Recentsurgeryortrauma(within2wk)ActiveinternalbleedingKnownbleedingdisorderSuspectedaorticdissention主動脈剝離Relativecontraindications:HistoryofstrokeAcute,poorUncontrolledhypertension(BP>180/110)Malignancy妊娠Acutepericarditis急性心包炎Pregnancy妊娠Activepepticulcer活動性消化性潰瘍Diabetichemorrhagicretinopathy糖尿病性視網(wǎng)膜病變Artialfibrillation房顫nursingcareforthrombolytictherapyECG,vitalsigns,heartandlungassessmentsarecompletedasoftenasevery5minutestoevaluatethepatient’sresponsetotherapy.Whenreperfusionoccurs,severalclinicalmarkersmayoccurs,nursesshouldmonitorthem,thosesignsofreperfusionincludeschestpainresolution,returnofSTsegmenttobaselineontheECG,thepresenceofreperfusiondysrhythmias再灌注性心律失常(prematureventricularcontractions室性早搏,ventriculartachycardia室性心動過速,ventricularfibrillation心室顫抖),rapidriseoftheCKenzymeswithin3hrsoftherapy,peakingwithin12hrs.nursingcareforthrombolytictherapyAnothermajorconcernwiththerapyisreocclusion動脈重新堵塞oftheartery,becauseofthispossibility,anIVbolusisgiven,followedbyheparindriptomaintainthepatient’sPartialThromboplasmTime(PPT)局部凝血酶原時間atonetotwotimesnormal,thispreventanotherclotformforminginthecoronaryartery.Themajorcomplicationwiththrombolytictherapyisbleeding.Thenursesmustpayparticularattentiontosignsandsymptomsofbleedingsuchasgingivalbleeding牙齦,dropinBP,anincreasinginHR,hematuria血尿,asuddenchangeinpatient’slevelofconsciousnessandoozing滲出ofbloodfromIVorcathetersite.Therapeuticmanagement

9.PercutaneousCoronaryIntervention(PCI)冠狀動脈介入治療BalloonStentLaserRotablatorPercutaneoustransluminalcoronaryangioplasty(PTCA)

經(jīng)皮腔內(nèi)冠狀動脈成形術(shù). Percutaneoustransluminalcoronaryangioplasy(PTCA)

經(jīng)皮腔內(nèi)冠狀動脈成形術(shù)

. Percutaneoustransluminalcoronaryangioplasy(PTCA)

經(jīng)皮腔內(nèi)冠狀動脈成形術(shù)

. PCIComplication冠狀動脈介入治療的并發(fā)癥Acuteabruptclosureofcoronaryvesselsseriousarrhythmias:VT室速，VF室顫。Cardiactamponade心包填塞VascularcomplicationLowbloodpressureStrokeHemorrhageRenalfailureHeartattackDeathCoronaryarterybypasssurgery(CABG)

冠狀動脈搭橋手術(shù)Coronaryarterybypasssurgery(CABG)

冠狀動脈搭橋手術(shù)Pharmacologicmanagement藥物管理IVnitroglycerin硝酸甘油IVMorphine嗎啡Morphinecanreduceanxiety,decreasecardiacworkload,reducecontractility,lowerBPandslowtheHR.Antidysrhythmicdrugs抗心律失常藥物DystrhythmiaarethemostcommoncomplicationsafterMI.Β-BlockersCalciumchannelblockersAngiotensin-convertingenzymeinhibitorsStoolsofteners

NutritionmanagementDietisrestrictedinsaturatedfats飽和脂肪和

andcholesterol膽固醇andissometimeslowinsodiumtopreventfluidretention.Thepatientmayhaveaclearliquiddietthefirstdaywhentheremaystillbenausea.NursingdiagnosisandinterventionAcutepainrelatedtolacticacidproductionfrommyocardialischemiaandalteredmyocardialoxygensupply.Administeroxygenthroughnasalcannulatoincreaseoxygenationofmyocardialtissueandpreventfurthertissueischemia.AdministermorphinesulfateIVasneededtodecreaseanxiety,elevatedpainanddecreasecardiacworkload.Monitorvitalsignsq1-2hrtoprovideon-goingassessmentofpatient’sresponsetotreatment.NursingdiagnosisandinterventionAlteredcardiactissueperfusionrelatedtomyocardialdamage,ineffectiveCOandpotentialpulmonarycongestionProvidelong,uninterruptedrestperiodtopromotecardiacrestandhealing.Minimizecardiacworkloadduringhealing.Explainnecessityofbedrestanddecreasedactivitytopromotepatientcooperation.Allowrestperiodsbetweenconcentratednursingcaretimetoreducefatigueandoxygenrequirementsofmyocardium.Assesurineoutputtodetermineadequacyofrenalbloodflow.NursingdiagnosisandinterventionImpairedgasexchangerelatedtoineffectivebreathingpatternanddecreasedsystemictissueperfusionsecondarytodecreasedCO.Elevatedheadofbedtoallowgravitytolowerthediaghragmanddecreasetheworkofbreathingandreducevenousreturn.Holdmorphineandnotifyphysicianifrespiratoryratelessthan10-12/minbecausemorphineisarespiratorydepressant.Maintainoxygentherapyasorder.NursingdiagnosisandinterventionActivityintolerancerelatedtofatiguesecondarytodecreasedCOandpoorlungandtissueperfusionMeetpatient’sneedquicklyandefficientlytoconserveenergyandpreventanxiety.Encouragepatienttomaintainbedrest.MonitorBP,pulse,respirationandcolortomonitorpatient’sresponsetoactivityandtoadjustasnecessary.AdministeroxygenduringactivitytoincreasesO2availabilityforcardiacandotherorganperfusion.Nursingdiagnosisandinterven