Evidence-BasedMedicine(EBM)

實證醫學之經驗談顏鴻章InstituteofEmergencyandCriticalCareMedicineDepartmentofEmergencyMedicineTaipei-VeteransGeneralHospitalNationalYang-MingUniversityWhatisEvidence-BasedMedicine(EBM)?Evidence-basedmedicine(EBM)requirestheintegrationofthebestresearchevidencewithourclinicalexpertiseandourpatient’suniquevaluesandcircumstances.BybestresearchevidenceByclinicalexpertiseBypatientvalues

BypatientcircumstancesEvidence-BasedMedicine(EBM)是整合目前臨床上最好的研究結果與配合醫師專業能力，針對病患問題在各種不同的臨床環境與個人價值下，做最適當的診治模式。HowdoWeActuallyPracticeEBM?Step1:convertingtheneedforinformation(aboutprevention,diagnosis,prognosis,therapy,causation,etc.)intoananswerablequestion.Step2:trackingdownthebestevidencewithwhichtoanswerthatquestion.Step3:criticallyappraisingthatevidenceforitsvalidity(closenesstothetruth),impact(sizeoftheeffect),andapplicability(usefulnessinourclinicalpractice).Step4:integratingthecriticalappraisalwithourclinicalexpertiseandwithourpatient’suniquebiology,values,andcircumstances.Step5:evaluatingoureffectivenessandefficiencyinexecutingsteps1–4andseekingwaystoimprovethembothfornexttime.IncorporatingEBMintoInpatientRoundsAdmissionrounds(aftereveryperiodoncall,alloverthehospital,bypost-callteamandconsultantMorningreport(everyday,sittingdown,byentiremedicalservice)Workrounds(everyday,ononeorseveralwards,bytrainees)Consultantwalkingrounds(1-3timesaweek,oneorseveralwards,bytraineesandconsultantIncorporatingEBMintoInpatientRoundsReviewrounds(or“card-flip”)(everyday,sittingdownandatthebedside,bytraineesandconsultants)Socialissuesrounds(periodically,bytraineesandahostofotherprofessionals)Preceptorrounds(“pureeducation”)(1-2timesaweek,bylearners(oftenstratified)andteacher)“Down-time”or“deadspace”duringanyroundIncorporatingEBMintoInpatientRoundsIncorporatingEBMintoInpatientRoundsCanSynopsesofEvidenceReallyGetThereThatFast?SeveralformatsincludingStructuredsynopsesonpaperinabinder(“bigredbook”,“medicineconsultnotebook”)NotebookcomputercarriedbycartPortabletextbookformat(e.g.ClinicalEvidenceorEvidenceBasedAcuteMedicine),PDAwithconcisesummariesInstantelectronicaccessPubMed,CochraneReviews,ACPJournalClubOnline,Evidence-BasedOnCall,andClinicalEvidence,forbothPCsandPDAs.實證醫學教學三種方式臨床個案模式的實證演練以證據模式來教導臨床醫學教導特定實證醫學的技巧臨床個案模式的實證演練

使用臨床證據於病患照顧上。以實際照顧病患個案來教學。如何整合證據作為臨床判斷的過程。舉例：

一位住院病患有上肢深度靜脈曲張；問題：你知道這樣的病人具有哪些潛在性疾?。勘壤秊楹危吭\斷流程表為何？

以證據模式來教導臨床醫學

使用臨床證據於病患照顧上的學習模式。將實證醫學觀念與其他的臨床知識結合，用於教學上。整合實證醫學與其他臨床醫學知識後用於病患身上結果的評核。舉例：(1)當你聽到病患的心音有S3gallop時，你診斷他具有心臟衰竭的正確性為何？(2)一位下腹疼痛的病患到急診就診後，你的診斷懷疑是急性闌尾炎；問題：你知道這樣的疾病常發生在年輕或老年人？比例為何？你知道有Alvaradoscore嗎？如何使用？可以不開刀僅使用抗生素就可以？

教導特定實證醫學的技巧

如何簡潔的瞭解與使用證據。以教練的方式來教學。實際演練實證醫學五大步驟(如何詢問問題？如何尋找資料？如何評核證據？如何應用證據？如何評估應用這些資料於臨床執業過程的正確性、實用性與可行性。舉例：當我們在學習照顧一位新診斷卵巢癌的病患時，你在臨床上應該如何結合臨床知識佐以實證醫學觀念去面對她？AskingQuestionsExercise:studydesignsWhatisthequestion(PICO)ofthestudy?Whatisthepurposeofthestudy?InterventionFrequency(incidenceorprevalence)DiagnosticaccuracyPrognosis(ornaturalhistory)AetiologyandriskfactorsWhichstudytypewouldgivethehighestqualityevidencetoanswerthequestion?(levelofevidence)Whichisthebeststudytypethatisalsofeasible?Whatisthestudytypeused?FormulateanAnswerableQuestionExample—Stockingsforlongflights?A43yearoldmaleaskedforsomerepeatprescriptionsandadviceaboutpreventingdeepveinthrombosisona12hourflight(hisbrotherhadhadonelastyear).Yousuggeststockingsasthemosteffectiveprevention.QuestionPatientorPopulation:__Inpatientsonlongflights___InterventionorIndicator:__docompressionstockings___Comparator:__nocompressionstockings___Outcome:__preventdeepveinthrombosis(DVT)___Questionsentence:Inpatientsonlongflights(P),docompressionstockings(I)preventDVT(O)?LibrarySearchingSessionUsingPubMedasanexample:GotoandselectClinicalQueriesSelecttheappropriateCategory(usually“therapy”whichisthedefault)TypeinthemostcrucialsingleelementofyourPICOsearch(usuallytheIortheP)Ifyoursearchreturnsnoarticlesthenclickthe“Broad”scopeIfyoursearchreturnsmorethan30articlesthentryaddingmorePICOelements,e.g,ifyouusedonlythe“I”nowtrysearchingtheIandPSelectthebestsinglearticleandrecordwhyyouchoosethearticleyoudid.CriticalAppraisalofaTherapyStudyYouareseeinga48yearoldmanwhohasjustrecoveredfromidiopathicpericarditisandheisaskingaboutthechanceofrecurrenceandwhetherhecandoanythingtopreventit.Yourecallhearingsomethingaboutanewtrialrecently,butcan’trememberthedetails.CriticalAppraisalofaTherapyStudyDecidewhatquestion(PICO)thestudyaskedandansweredWhethertheinternalvalidityofthestudyissufficienttoallowfirmconclusions(allstudieshavesomeflaws;butaretheseflawssufficienttodiscardthestudy?)CriticalAppraisalofaTherapyStudyIfthestudyissufficientlyvalid,lookatandinterprettheresults—whatistherelevanceorsizeoftheeffectsoftheintervention?WhatistheRelativeRiskReduction(RRR)andAbsoluteRiskReduction(ARR)?Decidewhetherandhowtheresultswouldapplytoourpatientabove.Thenroleplayexplainingtheconditionandtreatmenttoapatientusingthefollowingsteps:Theprognosis,ie.ChanceofrecurrenceTheimpactoftreatmentonthisCriticallyAppraisedTopicPresentationTemplateGiveadescriptionoftheclinicalsituationandtheclinicalquestionyouneedtoanswer.Question(PICO):Giveyoursearchstrategyincluding:(a)databaseused,(b)searchtermsused,and(c)numberofpapersidentified,and(d)whydidyouchoosetheparticulararticle?CriticallyAppraisedTopicPresentationTemplateWhatwasthequestionofthestudy?Appraisethevalidityofthestudy.Whatweretheresultsofthestudy?Statehowthestudyappliestothepatientyouidentified.CLINICALSCENARIOA1-year-oldboyisseeninourofficeduetocoughwithsputumandmildshortofbreath(SOB)for1day.Hewasrelativenormalbefore.Thistime,hehadthesymptomsofcoughandSOBwithmildwheezsonoccasion.Feverwithupto38.30Cwasnoted.Thephysicalexaminationrevealedincreaseusingofrespiratoryaccessorymuscle,andhigh-pitchwheezoverbilateralbasallungs.ThelaboratoryexaminationrevealedmildleukocytosisandCXRshowedincreasedinfiltrationoverbothbasallungfield.CriticallyAppraisedTopicPresentationExampleThepatient&clinicalquestionA1yearoldboywithfirst-timebronchiolitisvisitsourOPD.Youmaysuggestthatbronchodilatorscanproducesmallshort-termimprovementsinclinicalscoreandoxygenation.Question(PICO):Ininfantswithbronchiolitis(P),dobronchodilator(I)providebenefitsinclinicalimprovement(O)?CriticallyAppraisedTopicPresentationExampleSearchstrategyPubMed:Clinicalqueries(withtherapyfilters)BronchiolitisANDbronchodilator72papersincluded1CochraneDatabaseSystemicRev.2006,Jul.Areviewarticleincluded22clinicaltrialand1428infants.CriticallyAppraisedTopicPresentationExampleThestudy—thequestionandappraisal StudyQuestion:Ininfantswithbronchiolitis,dobronchodilatorprovidemorebenefitsinclinicalimprovementthanplacebo?CriticallyAppraisedTopicPresentationExampleThestudy—thequestionandappraisal

Randomisation:Allwererandomized,double-blind,placebocontroltrials.

Ascertainment:MultipleRCTsanalyzedinthismeta-analysisreview;thisisadequate.

Measurement:double-blindintreatmentdesignthroughevaluationbyclinicalscore,oxygenation,rateofhospitaladmission,durationofhospitalization.CriticallyAppraisedTopicPresentationExample—ResultsTwenty-twoclinicaltrialswith1428infantswithbronchiolitiswereincludedinthisreview.Ineighttrials,with468infants,therewasnoimprovementinclinicalscorefor43%ofthosetreatedwithbronchodilatorscomparedto57%ofthosetreatedwithplacebo(oddsratio(OR)fornoimprovement0.45,95%confidenceinterval(CI)0.15to1.29).Therewasastatisticallysignificantbutclinicallymodestimprovementintheoverallaverageclinicalscore(standardizedmeandifference(SMD)-0.48,95%CI-0.62to-0.33).CriticallyAppraisedTopicPresentationExample—ResultsTherewasnostatisticallysignificantimprovementinoxygenationoverall(weightedmeandifference(WMD)-0.57,95%CI-1.17to0.03).Subgroupanalysesshowedaslightlygreatereffectsizeinoutpatientstudies,wheretherewereshorterfollowupdurations,thanininpatientstudiesforbothoximetry(outpatientsWMD-0.84,95%CI-1.59to-0.10versusinpatientsWMD-0.25,95%CI-1.18to0.67)andaverageclinicalscore(outpatientsSMD-0.68,95%CI-0.87to-0.49versusinpatientsSMD-0.23,95%CI-0.44to-0.01).CriticallyAppraisedTopicPresentationExample—ResultsBronchodilatorrecipientsshowednoimprovementintherateofhospitaladmissionaftertreatmentasoutpatients(18%versus26%,OR0.70,95%CI0.36to1.35)ordurationofhospitalizationforinpatients(WMD0.02,95%CI-0.32to0.36).Theinclusionofstudiesthatenrolledinfantswithrecurrentwheezingmayhavebiasedtheresultsinfavorofbronchodilators.CriticallyAppraisedTopicPresentationExample—ResultsAUTHORS'CONCLUSIONS:Bronchodilatorsproducesmallshort-termimprovementsinclinicalscores.Thissmallbenefitmustbeweighedagainstthecostsandadverseeffectsoftheseagents.CriticallyAppraisedTopicPresentationExample—ImplicationforPracticeBronchodilatorsproducesmallshort-termimprovementsinclinicalscoresamonginfantswithbronchiolitisandmayslightlyimproveoxygenationinthosetreatedasoutpatients.However,giventhehighcosts,incidenceofadverseeffectsanduncertainefficacybasedonthefindingsofthismeta-analysis,bronchodilatorscannotberecommendedforroutinemanagementoffirst-timewheezerswhopresentwiththeclinicalfindingsofbronchiolitis.Bronchodilatorsshouldnotbeusedinpatientswhoarehospitalizedwithbronchiolitis.CriticallyAppraisedTopicPresentationExample—ImplicationforPracticeCriticallyAppraisedTopicPresentationExample(2)Thepatient&clinicalquestionA43yearoldmaleaskedforsomerepeatprescriptionsandadviceaboutpreventingdeepveinthrombosisona12hourflight(hisbrotherhadhadonelastyear).Yousuggeststockingsasthemosteffectiveprevention.Question(PICO):Inpatientsonlongflights(P),docompressionstockings(I)preventDVT(O)?CriticallyAppraisedTopicPresentationExample(2)SearchstrategyPubMed:Clinicalqueries(withtherapyfilters)Flight*ANDstocking*ANDDVT6papersincluded2separatetrialsTheScurrarticlewasthelargertrial,andqualityappearedequalCriticallyAppraisedTopicPresentationExampleThestudy—thequestionandappraisal StudyQuestion:Inpatientsonflightsover8hoursineconomyclass,doGrade-Ibelow-kneecompressionstockings,comparedtonostocking,preventultrasound-detectedDVT?CriticallyAppraisedTopicPresentationExampleThestudy—thequestionandappraisal

Randomisation:wasbysealedenvelope(notideal)butleadtoreasonablebalancethroughmorefemaleappearedtoreceivestockingsthanmales.

Ascertainment:therewasan86%followupandultrasoundineacharm;thisisadequate.

Measurement:throughstockingswereremovedpre-ultrasound,thesonographermayhaveseenthestockingmarkandhencebeenunblinded.Thestudyhassomeflaws,buttheseareprobablyinsufficienttoexplainthesizeoftheresultsCriticallyAppraisedTopicPresentationExampleTheresults DVToccurredin12%oftheNostockinggroupand0%oftheStocki