Clinical Thinking: Evidence, Communication and Decision-Making

133 Pages·2006·1.447 MB·English

Clinical Thinking
Clinical
Thinking
Evidence, Communication
and Decision-Making
Chris Del Mar
BondUniversity,Queensland,Australia
Jenny Doust
UniversityofQueensland,Queensland,Australia
Paul Glasziou
UniversityofOxford,Oxford,UK
(cid:2)C 2006ChrisDelMar,JennyDoustandPaulGlasziou
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Firstpublished2006
1 2006
LibraryofCongressCataloging-in-PublicationData
DelMar,Chris.
Clinicalthinking:evidence,communicationanddecision-making/ChrisDelMar,
JennyDoust,PaulGlasziou.
p.;cm.
Includesbibliographicalreferences.
ISBN-13:978-0-7279-1741-6
ISBN-10:0-7279-1741-2
1.Clinicalmedicine–Decisionmaking. 2.Evidence-basedmedicine.
[DNLM:1.PatientCareManagement–methods. 2.Communication.
3.DecisionMaking. 4.DiagnosticTechniquesandProcedures. 5.Evidence-Based
Medicine–methods. 6.ProblemSolving.W84.7D359c2006] I.Doust,Jenny.
II.Glasziou,Paul,1954- III.Title.
R723.5.D452006
616–dc22
2005037642
ISBN-13:978-0-7279-1741-6
ISBN-10:0-7279-1741-2
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Contents
Foreword,vii
Preface:whatthisbookisabout,ix
Chapter1 Principlesofclinicalproblemsolving,1
Chapter2 Communicationinclinicalcare,12
Chapter3 Modelsofdisease,27
Chapter4 Diagnosis,38
Chapter5 Fineartofprognostication,58
Chapter6 Makingclinicalmanagementdecisions,71
Chapter7 Monitoringinchronicdisease,84
Chapter8 Screeningfordisease,healthpromotionand
diseaseprevention,99
Chapter9 Endpiece,114
References,115
Index,123
v
Foreword
Every experienced doctor appreciates – and every newly-qualified doctor
quicklydiscovers–thatknowingthefactsisnotthesameasknowingwhatto
do.Diseasesdon’tconformtothetextbookversions.Patientscanbeidiosyn-
cratic and sometimes irrational. So can doctors. Research evidence is often
inconsistent,andeventhemostup-to-datepaperisneverthelastword.The
so-calledinformationexplosioncanconfuseaseasilyasitcanilluminate.Ev-
ery protocol, guideline and code of good practice immediately reminds the
practisingclinicianofahundredexceptions.
The hallmark of the trustworthy doctor – many would say it is a defining
characteristicofatrueprofessional–istheabilitytomakejudgementsinthe
faceofuncertainty.Doctorshavetobegoodatinterpreting,atprioritising,at
makingcompromises,atseeingwhatmattersamidawelterofcomplication,
andatsometimesinsistingthatwhatseemsrightintheorywouldbedamaging
intheflesh.Facedwithsuchacomplextask,itistemptingtotakerefugeina
numberofeasybutflawedpositions.‘IwillonlyeverdowhatIcanjustifywith
evidence’isonesuch.‘I’lljustdowhatIalwaysdo,orwhatmyteachersalways
did’isanother.Butthefirstsoonleadstoparalysis,thesecondtodangerous
sloppiness.Soundclinicalthinking,andtheprofessionaljudgementthatflows
fromit,isneitherslavishlyobedienttoanyrulenorrecklesslydisregardingof
thebestavailableinformation.
Thequestionfordoctorsateverystageoftheircareersishowtheirthinking
skillsaretobeacquired,developed,honed,maintained,andprotectedagainst
inertiaandatrophy.Surfingtheexponentialwaveofnewknowledgeisnec-
essary,butnotsufficient.Preservingone’sfascinationwithhumannaturein
itsmanymanifestationsthroughliterature,theartsandhumanitiesishelpful,
desirable,butnot–forsomespecialitiesatleast–essential.Thenecessarycom-
plementtoboththeseistocultivatethehabitofcriticalreflectionuponone’s
ownpractice,conductedwithgenuinecuriosityandhumility.Self-reflection
isanotherdefiningcharacteristicofatrueprofessional,andthatiswhatthis
book embodies. To read it is to learn the value of thinking about how one
thinks. The reader will benefit, but his or her patients will do so in greater
measure.Patientsdeservetohavedoctorswhonotonlyknowtheirstuffbut
alsoknowhowtoapplythatknowledgetothehumanpredicamentsthatdaily
confrontthem.
RogerNeighbourMADScFRCPPRCGP
President,RoyalCollegeofGeneralPractitioners
Bedmond,December2005
vii
Preface: what this book is
about
Thisbookisdesignedtohelppeopleunderstandtheclinicalthinkingneeded
topracticesuccessfully.
It is based on the simple notion that there are two sorts of learning that
we need for practice: knowledge and skills (of the diagnosis and manage-
mentofdiseasesandassociatedsymptoms),andtheabilitytosynthesisethis
information into clinical decisions. The knowledge and skills can be further
subdivided into background information (the basic information, made up of
anatomy,biochemistry,physiology,psychology,pathologyandsoon)needed
to understand the principles of caring for sick people, and the foreground in-
formation(theresearchwhichbestguidesmanagement).
Practicing medicine is not just about recalling facts, however. It is about
being able to process the facts in order to make choices. All of clinical work
canbethoughtofasdecisions,evensuchhands-onskill-basedactivitiessuch
assurgery.Ofcourse,thefirstsetoflearningenablesonetodecidewhatthe
choicesare.Buthavingassembledthenecessaryinformation,howdoesone
goaboutdecidingwhatactuallytodo?
The major revolution in foreground information has been the rising star of
evidence-based practice (EBP), or evidence-based medicine (EBM). This has
changedthewaywethinkofknowledge:nolongerthestaticstuffthatcanbe
hauledoutofbooksorstuffedintotheheadsofmedicalstudentsandregistrars,
butsomethingdynamicthatweshouldbepullingdownelectronically,often,
andnotevenbotheringtorememberbecauseitwillbeoutofdatebythetime
wehavecommittedittomemory.WeallthreeareveryinterestedinEBP.But
thatisnotthesubjectofthislittlebook.Ratherwewrotethistohelpsetout
(as much as anything for our own minds!) some of the cognitive processes
that we think make it easier to apply the knowledge and skills into clinical
practice.Wethreedecided,whileenjoyingthebrainstormingthatwentinto
preparingforthebook,thatwewishedsomethinglikeithadbeenwrittenfor
uswhenwewerestudentsandregistrars.
Whatwehavedoneinthisbookistogathertogetherwhatisknownabout
the art and the science of how we use the facts of medicine to solve the
problemswefaceasclinicians.Someofthescienceiscounter-intuitive.This
iswhatmakesitsofascinating.Wehaveincludedsomeoftheitemsthatwe
findhelpfulorunexpected,andtriedtosynthesisethemintoastory.Hopefully
youtoowillfindthatthisisnotonlyhelpful,butalsomakesclinicalpractice
evenmorefun.Whereevidenceforsomeofthemoreoutrageousclaimsexists
ix
x Preface:whatthisbookisabout
n Background information
o
ati
m
or
nf
of i
nt
u
o Foreground information
m
A
Time: maturation as a clinician →
Figure Differenttypesofinformationneededforsuccessfulclinicalpractice.Adapted
fromSackettetal.1
we have quoted it. But on the whole this book is not so much an academic
exerciseasahandbook.Hopefully,itwillhelpusalltobebetterclinicians.We
hopeyoufinditso.
The way the book is written is to set out the framework of the thinking
in chapters. We often illustrate the principles with a ‘case’ (many from our
ownpractices)tohelpshowhowtheymightbeapplied,andthenattheend
of each section we show how they could be applied into clinical practice by
explainingthemtothe‘patient’asadialogue.
Whoarewe?WeareacademicgeneralpractitionerswhometupinQueens-
land. We all worked in the same clinical general practice while we worked
togetherinacademia,beforespreadingout.Wedidacertainamountofsitting
around,drinkinggreenteaandthinkingaboutthisbook.Oneconsequenceof
ourbackgroundisthatourexamplesarefirmlybasedonprimarycare.Forthis
wemakenoapology.Wethinkthatifonecangetclinicalthinkingtobeuse-
fulingeneralpractice,thatseatofthegreatestunknown,leastdifferentiated
disease,thenitislikelytobeusefulalmostanywhereinclinicalpractice.
Wededicatethebooktopatients,forwhomwehopethiswillmakeadif-
ference,reducetheirsuffering,andhelptheirdoctorsmanagetheirillnesses
better.
ChrisDelMar
JennyDoust
PaulGlasziou
Clinical Thinking: Evidence, Communication and Decision-Making
Chris Del Mar, Jenny Doust, Paul Glasziou
Copyright © 2006 by Chris Del Mar, Jenny Doust and Paul Glasziou
CHAPTER 1
Principles of clinical
problem solving
Doctors constantly make decisions. It may not always feel like this. In fact,
if we have been in practice for a while, it can begin to feel as if much of
ourpracticeisroutine.Thisisbecause‘whenthingsareproceedingnormally,
expertsdon’tsolveproblemsanddon’tmakedecisions:theydowhatnormally
works’.2
Part of becoming a competent doctor is learning the vast number of facts
necessarytopracticemedicine.Themoreimportantpartofourlearningisto
modelthedecision-makingbehaviourofmoreexperiencedclinicians,learning
the routines that they use to collect and process the facts of each new case
and thereby learn to make the sort of decisions that we all need to make as
clinicians(seeBox1.1).
Ourclinicaltraininggivesusthecontextandtheexperiencetoprocessthe
informationofeachnewpatientandtomapitagainstourstoreofmemorised
facts.Thewaythatwelistentoandrecountthestoriesofourpatientsbecomes
ritualised,withstrictruleslikeaGreekchorus.Thetextbookfactsthatwehave
learntbegintoattachthemselvestoexperience,tothestoriesofourpatients
and to our own experience of working in health care. We now know that
clinical knowledge is mostly stored in memory as stories or templates, and
notascollectionsofabstractedfacts.3 Aswegainclinicalexperience,weare
graduallyabletousethedetailsthatweseeandhearwithbetterdiscrimination
and with time we come to make decisions more or less intuitively, and may
evenfinditdifficulttoexplaintheintermediatestepsinourclinicalreasoning
(Box1.2).
Box1.1 ExamplesofTypicalClinicalDecisions
(cid:2)ShouldIdoatest?WhichtestshouldIdo?
(cid:2)CouldIbemissingadiagnosis?ShouldIbeinvestigatingthispatient
further?
(cid:2)WhichoftheavailabledrugsshouldIprescribe?Wouldthepatientbe
betterwithoutfurthermedication?
(cid:2)Isitalrighttodividethisstructureduringtheoperation–amIsureitis
aveinandnotanerve...?
(cid:2)ShouldIaskthepatienttocomeback?When?Howoften?
1
2 Chapter1
Box1.2 CharacteristicsofNovice,CompetentandExpert
Practitioners4
Thenovicepractitionerischaracterisedby:
Rigidadherencetotaughtrulesorplans
Littlesituationalperception
Nodiscretionaryjudgment
Thecompetentpractitioner:
Isabletocopewith‘crowdedness’andpressure
Sees actions partly in terms of long-term goals or a wider conceptual
framework
Followsstandardisedandroutinisedprocedures
Theexpertpractitioner:
Nolongerreliesexplicitlyonrules,guidelinesandmaxims
Hasanintuitivegraspofsituationsbasedondeep,tacitunderstanding
Usesanalyticapproachesonlyinnovelsituationsorwhenproblemsoccur
Because of our training and experience, we are able to practice medicine
without considering in great detail how we come to make clinical decisions.
Manyexpertandhighlycompetentclinicianshavenotstudiedtheprinciples
outlined in this book. We believe, however, that learning the principles of
clinicalproblemsolvingisimportantinordertoprovidethebestpossiblecare
forourpatients,andthatunderstandingtheseprincipleswillbeincreasingly
importantformedicalcareinthefuture.
Firstly,understandingthemethodsforclinicalproblemsolvingisimportant
whenaproblemariseswherewedonothavearoutineorpracticedapproach.
By its nature, this happens more frequently in general practice than in any
otherareaofmedicine.Itisprobablynoaccidentthatthethreeauthorsofthis
book, and many authors who write in this area, come from general practice
backgrounds.Butbeingabletodealwithnewandcomplexproblemsandbeing
abletomanageuncertaintyisimportantinallareasofclinicalmedicine.Being
able to understand the principles of clinical problem solving is particularly
importantwhenwearerelativelyjuniorandhavenotyetdevelopedenough
clinicalexperiencetoactmoreintuitively.
Secondly, understanding these principles gives us a framework for incor-
porating both new evidence and the values of our patients into our clinical
decisions.Evidence-basedmedicineisdescribedas‘theintegrationofbestre-
searchevidencewithclinicalexpertiseandpatientvalues’1,butitisnotalways
cleartoclinicianshowthisintegrationmightoccur.Twochangesmakeitim-
perativetofindmethodsforsuchintegration.Thefirstistherateatwhichnew
medicalknowledgeisadvancing.Thesecondisthegreaterdesireforpatients
to participate in decisions about their own health care. As another leader of
Principlesofclinicalproblemsolving 3
the evidence-based medicine movement described it: ‘medicine is indeed in
the middle of an intellectual revolution. Methods of reasoning and problem
solving that might have worked well in the past are not sufficient to handle
today’sproblems.’5 Theframeworkoutlinedinthisbookshowshowthein-
tegrationbetweenclinicalexpertise,researchevidenceandpatientvaluescan
begintooccur.
Thirdly, there are times when we can predict that intuitive or routine de-
cisionmakingmightfail.Beingawareofthepotentialcognitivebiasesinour
routinethinkingcanhelpustobebetterandsaferdoctors.
Finally, we have found that learning and thinking about the principles of
clinicalproblemsolvinghasimprovedourunderstandingofwhatwearedoing
as clinicians. All three of us have found that understanding these principles
makesourclinicalworkmorefun.
The framework for clinical problem solving
Studiesofnaturalisticdecisionmakinghaveshownthatexpertsmakingcrit-
icaldecisions,suchasfirecommandersinchargeofunitsfightinglargefires,
areoftenunawareofmakinganydecisions.6Thisiseventhoughtheyclearly
have to make decisions such as the need for extra units, when to withdraw
firefightersfromasituationandsoon.Whenaskedtoexplaintheirdecision-
makingprocess,thefirecommanderswillusuallyinsistthattheydonotmake
decisionsandthatitisobviouswhattodoinanygivensituation.Afteranalysis
ofhowtheyactuallymadecriticaldecisions,itseemsthatexpertsusetheirex-
periencetomatcheachnewsituationtoaprototype,andtousethisprototype
todecideonacourseofaction.Theymayrecognisethattheyneedtocollect
moredatatoclarifyasituationortore-evaluateasituationifconditionschange
over time, but at each point they are trying to match the situation to a pro-
totype.Themainelementsoftherecognitionprimeddecision-makingmodel
areshowninFigure1.1.Thismodelappearstobeveryconsistentwithwhat
weknowabouthowexpertcliniciansmakedecisionsinmedicine(Box1.3).7
For example, when a patient is admitted with a myocardial infarction, it is
importanttodecidequicklywhetherapatientshouldhavethrombolyticther-
apy or not. There are many factors that could determine this choice, but it
hasbeenshown,infact,thatdoctorsuseonlyafewofthesefeaturestomake
thedecision.Doctorsareoftenbetterthanclinicalalgorithmsordecisionsup-
port systems could be at determining when the clinical pattern does not fit.
For example, a case report in The Lancet describes a patient who presented
withchestpainandSTsegmentelevationintheanteriorleads.8 Themedical
team was preparing to give the patient thrombolytic therapy, when the pa-
tientremarkedthathecouldnotmoveorfeelhislegs.Recognisingthatthis
didnotfittheclinicalpatternofmyocardialinfarction,theteaminvestigated
further. A CT of the patient’s chest and abdomen showed a thoracic aortic
dissection.