1、Lecture 1Recognising and capturing clinical uncertaintyDr Carl Thompson, University of YorkLecture 1Recognising and captForeground and background knowledgeBackground knowledgeforeground knowledgeExpertise and decision makingDr Carl Thompson, University of YorkForeground and background knowclarificat

2、ionClinical uncertaintyClinical judgementClinical decision makingEvidence based decision makingDr Carl Thompson, University of YorkclarificationClinical uncertaiClinical uncertaintyNot certainly knowing or knownSourcesDefining a diseaseMaking a diagnosisSelecting an interventionObserving outcomesAss

3、essing patient preferencesCombing information in a decisionDr Carl Thompson, University of YorkClinical uncertaintyNot certaiQuantifying UncertaintyTrue state of the patient cannot be directly observedClinician must use imperfect external cuesProbability as a language for expressing uncertaintyDr Ca

4、rl Thompson, University of YorkQuantifying UncertaintyTrue stProbability FundamentalsStrength of beliefA number between 0 and1 that expresses an opinion about the likelihood of an eventProbability of an event that is certain to occur is 1Probability of an event that is certain to NOT occur is 0Dr Ca

5、rl Thompson, University of YorkProbability FundamentalsStrengTypes of probabilityTermdefinitionFormularangeProbabilityThe chance of an eventP0-1Proportionrelative frequency of a state P0-1PrevalenceThe proportion of a group with a specific diseaseP0-1PercentageProbability expressed as a frequency pe

6、r 100P x 1000-100FrequencyProbability expressed per sample (1 per 1000)P0 denominatorOdds Ratio of the probability of an event to its complementP(/1-P)0-infinityIncidence rate Occurrence of new disease casesP/t0-infinityIncidence proportionThe proportion of people who develop a new disease or event

7、during a period of time P0-1Risk The probability that an individual develops a new disease during or event a specified period of time P0-1Dr Carl Thompson, University of YorkTypes of probabilityTermdefiniComponents of Probability EstimatesPersonal experiencePublished experience - evidenceAttributes

8、of the patientDr Carl Thompson, University of YorkComponents of Probability EstiClinical decision and judgementClinical judgementAssessment of alternativesClinical decision Choosing between alternatives(Dowie 1988)Dr Carl Thompson, University of YorkClinical decision and judgemenThe decisions clinic

9、ians make.Diagnosis and test ordering (Dx)Treatment (Rx)TargetingTimingreferralCommunicating (risks and benefit info)Seeking more informationS.D.O. (service delivery and organisation)Dr Carl Thompson, University of YorkThe decisions clinicians make.Clinical uncertainty the good newsAeschylus hope co

10、mes from the lack of certainty of fate Complete certainty = lack of hopeExamination results predicted life success (100% accurately)Learning at age 12 that you possess the Alzheimers geneAdaptation to Huntingtons and HIV statusDr Carl Thompson, University of YorkClinical uncertainty the gooAsking qu

11、estionsBackground questions:General knowledge about a disorder A root (who, what, when, how, and why) a verb A disorder or aspect of a disorderE.g. what causes angina?Dr Carl Thompson, University of YorkAsking questionsBackground queForeground questions P.I.C.O.Specific knowledge about management of

12、 people with a disorder Population: the people who are on the receiving end of your judgement and choicesIntervention: that which you are thinking of doing to (with?) them Counter intervention: the other choices nb. sometimes not in a question when no choiceOutcome: what do you want see happen (or n

13、ot happen) as a result of your choice?Dr Carl Thompson, University of YorkForeground questions P.I.C.O.SPopulation - Can Include:Disease or condition Sex, age, race, socio-economic setting Stage of disease, care settingDr Carl Thompson, University of YorkPopulation - Can Include:DiseInterventions -

14、Can Include:General or specific interventions treatment options or specific drug, risk factors or specific cause Level of intervention Frequency/dosage Stage of intervention prevention, secondary prevention, early, advanced Delivery of intervention setting, professional group, self-medicationDr Carl

15、 Thompson, University of YorkInterventions - Can Include:GComparisons With The Intervention - Can Include:Standard practice Gold standard intervention Placebo Other specific comparisonsDr Carl Thompson, University of YorkComparisons With The InterventOutcomes - Can Include:Clinical Outcomes mortalit

16、y, reduction of symptoms, adverse effects Provider-oriented Outcomes cost-effectiveness, benefits to service Patient-oriented Outcomes QoL, satisfaction, acceptanceDr Carl Thompson, University of YorkOutcomes - Can Include:ClinicaWhy bother with PICO?Helps focus scarce learning time on relevant evid

17、ence for patient needHelps focus scarce learning time on evidence that addressed your knowledge needsSuggests high yield search strategiesSuggest the form useful answers might take Aid referrals by clearly communicating needsAs a basis for teaching others (clarity in communication)Leads to answers i

18、ncreases your motivationDr Carl Thompson, University of YorkWhy bother with PICO?Helps focSome examplesIs sucrose a safe and effective analgesic during painful procedures in newborns?Do prenatal and postnatal home visits by nurses have long term effects on maternal and child outcomes?Do transparent

19、polyurethane dressings reduce dislodgement, phlebitis, and “tissuing” of peripheral IV catheters compared to gauze?Is exposure to parental tobacco smoke associated with an increased risk of asthma in school age children?Dr Carl Thompson, University of YorkSome examplesIs sucrose a safeYour go!popula

20、tioninterventionCounter interventionOutcomeDr Carl Thompson, University of YorkYour go!populationinterventionIntro to a Search Strategy:Start with a clear answerable question Break the question down into concepts Search each concept separately (use indexing terms, other indexing features, textwords

21、Combine terms Limit resultsDr Carl Thompson, University of YorkIntro to a Search Strategy:StSearching For Individual Concepts:Indexing terms (thesaurus terms, subject headings) eg. MeSH mapping Textwords synonyms alternative spellings and word endings truncation (usually $ or *) eg. manag$ proximity

22、 operators usually adj# or near# eg. home adj3 help exact phrase usually “ # ” eg. “clinical governance”Dr Carl Thompson, University of YorkSearching For Individual ConceCombining conceptsAND - Creates a smaller set; both concepts must be present. In this case the result set is the records which con

23、tain both the smoking and counselling concepts.Result setSmokingCounsellingDr Carl Thompson, University of YorkCombining conceptsAND - CreatCombining conceptsOR - Creates a larger set; any or all concepts must be present. Used to link similar concepts. In this case the result set is the records which contain both the psychotherapy and counselling concepts (all the blue area)PsychotherapyCounsellingDr Carl Thompson, University of YorkCombining conceptsOR - CreateCombining conceptsNOT - Ex