Presentation on theme: "An Introduction to Clinical Decision Making"— Presentation transcript:
1 An Introduction to Clinical Decision Making Dr Graham R. NimmoChair, Scottish Clinical Decision Making Special Interest GroupClinical Skills Managed Educational Network and Scottish Clinical Skills NetworkHello and welcome to this interactive tutorial on clinical decision making. Once you have completed it you should have an enhanced idea of what is involved in CDM and hopefully will have surfaced and framed your own questions regarding cognition in the clinical context which will require further exploration both physically and into the literature. I would like to thank my colleagues in the Scottish CDM SIG for input to this work and particularly to thank Prof Pat Croskerry from Halifax, Nova Scotia for his advice, inspiration and slides!
2 Overview Intro to clinical decision making (CDM) The five second rule: a case based CDM challengeHow do we think and make decisions?What affects our CDM?How can we improve CDM and enhance patient safety?Next?CDM is a massive subject and this short introduction aims to give you an insight to the practicalities of CDM and a window onto the theoretical basis, particularly current theories of how we make decisions. This might influence your clinical practice and teaching.
3 CDM and non-technical skills Team workingDecision makingSituation awarenessTask managementDiagnosisPrognosisDecision making is one of the so-called ‘softer’ skills in clinical practice. It sits within the wider group of skills which are embraced in the terms human factors or non-technical skills and which are listed here. If you are interested in learning more about these look at the links at the end of this tutorial. There are a number of viewpoints as to which of them is most important, with some authorities viewing situation awareness as the critical element. My own take on the NTSs is that they shouldn’t be parcelled up into separate boxes but that there is overlap between the so-called domains and that decision making and communication probably flow through all of them. Diagnosis is a separate issue. The construction of a clinical picture in terms of what the underlying disease process is lies at the heart of all medicine whether the therapy is surgical, psychological, pharmacological, palliative, curative. As GH Rodger stated eloquently in his 1906 book ‘an introduction to the study of medicine’ “Medicine is a science by its means of study: it is an art by its applications”. Two branches concerning the medical art are defined: diagnosis (from Greek to know, through) and prognosis (from the Greek from, before, to know). These involve some of the most complex and difficult decisions which need to be made and often involve elements of uncertainty and judgment. More about these later.
4 CDM exercise 1 Think about your choice of speciality, profession, job What influenced you in that decision making?Of course decisions are made continuously in life, some trivial (HP sauce or tomato ketchup?), some monumental like ‘should I accept this job in Alaska?’ Speaking of jobs have a think about why you chose your particular career.
5 CDM exercise 2 Look at the next slide and ask yourself: “Which beach would I rather be on?”
6 A or B ?How did you decide that? Did you spend time and effort deciding? Or was it virtually instantaneous? More about that later…………
7 CDM in the acutely ill 21 year old with known asthma In respiratory wardPhone callDecisionsRecognitionLet’s think about our assessment process for this patient and the decision making necessary. Actually seeing the patient can give a huge amount of information to the experienced clinician. Physically going to look at the patient is more valuable than hearing about them over the phone: the five second rule relates to that initial sight of the patient where their demeanour and context are added to the standard clinical and physiological assessment . This disciplined noticing can avoid cognitive biases of the telephone caller. (This is equivalent to the lesson in Dawn’s telephone scenario in the other on line introductory module : speak to/look at the patient rather than getting second hand information). Let’s go through the process. We have already made the critical decision to GO TO SEE THE PATIENT.
8 The five second ruleSo to the patient: in the first few seconds our decision making and diagnostics may work in a very fast, efficient but potentially hazardous way. This is named System 1 thinking and its characteristics are listed on the next slide…
9 System 1 thinking: (intuitive) CDM in the acutely illIn the wardAssessment and managementLooks….Obs….ActionsSystem 1 thinking: (intuitive)Cognitive style HeuristicCognitive awareness LowCost LowAutomaticity HighRate FastReliability LowErrors UsuallyEffort LowPredictive power LowEmotional component HighScientific rigour LowThe immediate impression is based in what we define as System 1 thinking: impulsive, immediate, urgent. In the hands of an expert this can be invaluable although still potentially risky. In the hands of a novice it is quite likely to be dangerous. It involves emotion and rapid almost ‘reflex’ decision making. If we are aware that this process is happening we can step back from our decisions and examine them, check for errors and calibrate our decision making.
10 Importance of CDM in managing sick patients Patients still die from ‘simple’ things either missed, delayed or done sub-optimallyDecisions including diagnosisApprox 80% of clinical time spent in the cognitive domainClinical decision making is one of the key activities which underpins patient safety and the quality of patient experience.
11 THE FOUR KEY DOMAINS OF EMERGENCY CARE 1.Acute assessment + stabilisation with immediate investigations and support.Targeted secondary exam2.Monitors: reassessSurfaceInvasiveReal time or DelayedIllness severity3.CDMTeam workTask MxSituation AwarenessCritical Thinking4.Differential diagnosis/ definitive diagnosisImmediate, medium term and long term treatmentWe can think of a number of particular activities which need to happen simultaneously when we are dealing with a sick patient such as our young man with acute asthma: the familiar ABCDE approach is employed to help identify life threatening abnormalities which require immediate attention: usually respiratory failure (hypoxaemia with or without hypercapnia, shock, impaired conscious level or a combination of these as in severe sepsis or major trauma. Even within this standardised, structured approach there is a plethora of decisions to be made as you can see in the next few slides. In addition an assessment of illness severity must be made in order to guide the speed and level of intervention. In the next section relating to ABCDE approach and ISA the key clinical decisions are highlighted in yellow font.
12 1. Advanced First Aid ASSESSMENT Hello, how are you ? Response Airway: patent ?BreathingACTIONLook: obstructionListen: ? noiseClear or secure: headtilt/chin lift or jaw thrust? Airway: oral or nasal?High concn oxygen: mask type? Flow?
13 1. Advanced First Aid ASSESSMENT Sounds ? Common 3 are ? Causes are ? ACTIONClear and keep openGet help 2222?Advanced airway management required? Tracheal tube? Size? Cut to what length? Are drugs needed for anaesthesia and intubation? If yes, which?
14 For each ask ‘what is the diagnosis?’ 1. Advanced First AidASSESSMENTSoundsNil: complete obstruction or not breathingSnoring/gurgling: reduced GCS, foreign materialStridor: anaphylaxis, burns/thermal; tumour; abscess/infectionFor each ask ‘what is the diagnosis?’ACTIONClear and keep openGet help 2222PositioningAdvanced airway management required
15 1. Advanced First Aid plus 2. OBSERVERateVolumeSymmetryCharacterWork of breathingCompromiseIx & MONITORCXR, PEFR, ABGsRepeat observationsPulse oximetryTREATOxygenNebulisers
16 1. Advanced First Aid ASSESS Pulse: which pulse? Skin: cap refill time, temperatureBP: where? Which method?PHYSIOLOGYMAP = CO x SVRCO = HR x SVLow BP = decompensation
17 1. Advanced First Aid iv access iv access Site Upper limb Femoral Size Blood samplingiv accessUpper limbFemoralHigh flow: short and thickFluidsDrugs
18 Wide bore peripheral cannulae The bottom one is a straw!
19 1. Advanced First Aid Disability ? Conscious level, focal neurology DEFGDifficult bit
20 IMMEDIATE INVESTIGATIONS Arterial blood gases: O2, CO2, acid-basePotassiumGlucose can all be done on aHaemoglobin blood gas sample12 lead ECGCXRTargeted investigationsWhat should we do having analysed this information?Having a system and a routine can help reduce the cognitive load. Having a blood gas machine which can rapidly perform the most critical investigations which result in instability, and which are also rapidly improvable (usually), takes away the need to decide on them individually. The decision to obtain an arterial blood sample for analysis needs to be made and then a decision as to which artery to sample from is required. Once these and other investigations are available multiple decisions on supportive treatments (eg oxygen, ventilation, potassium, glucose, iv fluids, blood transfusion, analgesia), diagnosis and definitive treatments (eg antimicrobials, heparin, anticonvulsants and so on), prognosis, illness severity, where should they be looked after?
21 1. Advanced First Aid Evidence Environment: context Targeted secondary ExaminationExplanationEverything else…For completeness here is the E of the acute approach. Where the patient is and what is happening around them may affect CDM. See the reading list to access a paper on the impact of context on decision making.
22 Advanced First Aid=Phase 1:abcde abcde, treating as you goRepeated assessment and continuousmonitoring: patient better or worse ?Do we need enhanced abcde ?Targeted secondary examination
23 THE FOUR KEY DOMAINS OF EMERGENCY CARE 1.Acute assessment + stabilisation & immediate investigations and support.Targeted secondary exam2.Monitors: reassessSurfaceInvasiveReal time or DelayedIllness severity3.CDMTeam workTask MxSituation AwarenessCritical Thinking4.Differential diagnosis/ definitive diagnosisImmediate, medium term and long term treatmentAt the same time as all of this is going on with our asthma patient we need to establish monitoring: this will be determined by what is available? (context, ergonomics) and your experience, competence and capability. In severe or LT asthma a large bore iv cannula is mandatory and (ideally) an arterial line although time pressure may negate the latter.
24 Illness Severity Assessment Speed of action neededLevel & type of expertise: resuscitation;diagnostic; therapeuticWhere should the patient be ? Nursingintensity, monitoring, medical input?Definitive treatment: speed ?Rapid illness severity assessment is needed to answer these questions…However further information may help with this as the assessment, investigations and management proceed.
25 SEVERITY SCORING 1:CLINICAL ABNORMAL PHYSIOLOGYAirway compromisedResp ratePulse rateSBPGCSOBSERVATIONSBad<10 or >30<45 or >120<100 (110) or >200Fall of 2 points, <15Initially the ‘vital signs’ may be abnormal and indicate severity.
26 SEVERITY SCORING 2: INVESTIGATIONS ABNORMAL INVESTIGATIONSHypoxaemiaHypercarbiaPotassiumGlucoseH+Base excessLactateRESULTS<3 or >6 (ECG)<3 or >20>50 or <30< -5 or > +10Diagnosis ?As investigation results become available these add further to the assessment of illness severity.
27 Relationship between base excess and mortality in ICU Some specific results such as base deficit, lactate indicate tissue hypoxia and risk of death.Base Excess and Mortality Red = Dead Green = survivorICM 2001;27:74-83
28 SEVERITY SCORING 3: organ failures Clinical: cardiovascular (shock)CNS reduced conscious levelUrea and creatinine: renalABGs: respiratory (oxygenation+/or CO2 clearance)Clotting: coagulationWBC: bone marrowGut/liver: glucose; lactate; clinicalThirdly, as measures of specific organ systems function are reported a picture of how many organ systems are failing is built up. We know that the more systems involved the worse the patient’s outlook so this helps with prognostic decision making although
29 4. Differential Diagnosis, ultimate diagnosis and definitive treatment Get more historyTracheaChestJVP and heartAbdomenSkin, CNSGP, family, SASDeviationLateralising signs, wheeze, cracklesHS III or IV, murmursSwelling, pulsationRashes, neck stiffness, lateralising signsthe actual diagnosis (or diagnoses) and the response to both supportive and definitive treatment refines the prognostic decisions.
30 ASSESSMENT A clinical + B investigations C organ failures D diagnosis So you can see that a number of factors (which become available over time) are required to make decisions about prognosis. An understanding of this helps in decisions to refer patients for intensive care and in discussions with relatives and friends.
31 Decision making Diagnosis (and treatment) Is the diagnosis correct (complete) ?PrognosisAdmit ?Discharge ?Stop ?DistributedSo what other kinds of decisions are we making: some of these are listed above but I want to spend some time considering diagnostic decision making.
32 Diagnostic ErrorRanked 2nd cause of adverse events (Harvard study, 1991)Diagnostic failure highest in EM, GP, Gen MedPassing on to specialists in wards, ICU2/3 of claims against UK GPs are for diagnostic failureThis area is one of uncertainty with major patient safety implications.
33 Type 2 thinking (analytical) Cognitive style Systematic Cognitive awareness HighCost HighAutomaticity LowRate LowReliability HighErrors FewEffort HighPredictive power HighEmotional component LowScientific rigour HighDiagnosisHistory: fullExamination: completeInvestigationsDifferential DxTreatmentRefine diagnosisSo in order to make the diagnosis accurate we have developed and learned a painstaking approach which involves detailed history taking, systematic clinical examination, the performance of appropriate targeted investigations to allow us to create a differential diagnosis. Treatment is then started and the response of the patient helps to inform the subsequent refining of the diagnosis. This process can be neatly aligned to the profile of type 2 thinking. It requires high cognitive awareness, is costly etc
34 Categorising Clinical Decision Making Cognitive theory: traditionalTechnicalProfessionalDistributedTraditionally theory related to clinical practice has been psychologically based on a number of cognitive paradigms. However when you look at your clinical practice you will see that there are a number of domains into which most decisions can be placed: t, p, d.
35 Traditional cognitive taxonomy or “how you think it” Problem solvingPattern recognitionDecision analysis theoryHypothetico-deductive reasoningThere is a vast literature on this area but how useful these individual theories are on informing, supporting, helping our day to day CDM is not always clear.
36 CDM: a universal model of diagnostic reasoning IntuitiveExperiential-inductiveBounded rationalityHeuristicPattern recognitionHard wired responseThin slicingUnconscious thinking theoryAnalyticalHypothetico-deductiveUnbounded rationalityNormative reasoningRobust CDMAcquired, critical, logical thoughtMultiple branching/arborisationDeliberate, purposeful thinkingHowever if you fit these theories into a universal model which is built around system 1 and system 2 thinking and we start to examine our day to day decision making you can start to work out which kind of thinking you are engaged in for specific decisions. And if you are making intuitive decisions you should then ask “what influences my rapid fire decision making? Remember the beach question?
37 A or B ?How did you decide that? Using system 1 processes. But what about context? If you were an international art thief and you wanted to be inconspicuous which beach would you prefer to hide on?
38 What affects clinical decision making ? CDMWhat affects clinical decision making ?Knowledge and skillsBehaviours: attitude (multiple selves), emotions (affect: self, family, patients, relatives, colleagues), values.If you use system 1 processes as an expert you are often correct (remember the skin rashes? most experienced clinicians get the right diagnosis in a blink). However if you use these hardwired processes as a novice it could be way off the mark.
39 What affects clinical decision making ? ContextValuesAffectKnowledgeCritical thinkingInterruptionsClinical reasoningWordsNon-technical SkillsPhysical factorsStress and FatigueErgonomicsExperienceWhat we hearWhat we thinkCognitive biasesHeuristicsEpiphaniesGeographyNumerous factors affect decision making and this far from exhaustive list (in no particular order) gives an idea of the complexities underlying what is such an integral component of everyday clinical activity.
40 30 Cognitive Errors after Croskerry Aggregate biasGender biasPsych-Out ErrorsAnchoringHindsight biasRepresentativenessAscertainment biasMultip.AlternativesSearch satisficingAvailabilityOmission biasSutton’s SlipBase rate neglectOrder effectsTriage-CueingCommission biasOutcome biasUnpacking principleConfirmation biasOverconfidenceVertical line failureDiagnostic creepPlaying the oddsVisceral biasAttribution errorPosterior prob.Ying-Yang OutGambler’s FallacyPremature closureZebra retreatOne particular area which has been surfaced over the last few years is that of cognitive dispositions to respond. Pat Croskerry has catalogued and defined these innate human ‘failures of cognition’. Some are negative biases, others can be useful or detrimental. A detailed analysis of them is beyond the scope of this tutorial but to give a couple of examples: confirmation bias is where the clinician shoe-horns the patient into their preferred diagnosis; Ying-Yang Out is where boredom sets in: we have investigated this patient up and down the Ying Yang river so stop; Availability is that situation where you saw a patient with a certain condition last week so it is at the forefront of possibilities when you see a patient with similar symptoms and so on. The importance of knowing about these is that we can recognise when we are straying down one of these paths and by applying corrective processes known as cognitive forcing strategies we can avoid the biases and improve our CDM and enhance patient safety.
41 1 2 TYPE Calibration Diagnosis TYPE Intellectual ability Hard wiring Heuristics and BiasesAmbient conditions/ContextTask characteristicsAge and ExperienceAffective stateGenderPersonalityTYPE1processesRECOGNIZEDPattern RecognitionPatientPresentationPatternProcessorRationaloverrideDysrationaliaoverrideCalibrationDiagnosisRepetitionTYPE2processesPutting it all together we work using both S 1 and S 2 processes all the time toggling back and forth between them with influences from all of the factors included in this schema. If we understand where we are situated cognitively we should be able to improve CDM and patient management.NOTRECOGNIZEDIntellectual abilityEducationTrainingCritical thinkingLogical competenceRationalityFeedback
42 THE FOUR KEY DOMAINS OF EMERGENCY CARE 1.Acute assessment + stabilisation & immediate investigations and support.Targetted secondary exam2.Mons: reassessSurfaceInvasiveReal time or DelayedTissue hypoxia3.CDMTeam workTask MxSituation AwarenessCritical Thinking4.Differential diagnosis/ definitive diagnosisImmediate, medium term and long term treatmentSo this is where we are working clinically
43 Clinician factors: Evidence Based judgment, affect, Medicine Patient experiencePatientFactorsthese are the elements which need to be included in our approach
44 Solutions Training in critical thinking Training in major cognitive and affective biasesTraining in logical thoughtAwareness of self and metacognitionTimely feedbackTraining in cognitive forcing strategiesAnd these are some of the potential solutions and that will be where we go in the next tutorial ….