clinical decision making

Question 1

what is an error *

Answer 1

the failure of a defined action to be completed as intended (error of execution)

or use of a wrong plan to achieve an aim (error of planning)

Question 2

examples of medical errors (*

Answer 2

incorrect diagnosis

failure to employ indicated tests

error in performance of an operation, procedure or test

error in dose or method of using drug

Question 3

how much death in US is caused by medical error

Answer 3

3rd biggest cause of death

Question 4

what is the scale of medical errors in uk

Answer 4

medication errors have acsaused 12000 deaths

may contribute to 0.75-1.5 billion in additional health care expediture

Question 5

explain the case of WJ - medical error *

Answer 5

he has given chemo every 3 months

vincristine IV and cytosine IT (intrathecally - via spine)

vincristine was accidently injected IT = paralysis - switch off life support

Question 6

eg showing problem with dr nurse relationships *

Answer 6

problem is we follow morfe senior collegues than the correct procedure

med in cupboard said max dose 10mg

dr phoned (actor) and said draw up 20mg

21/22 nurses gave the high dose - trend is to obey dr

Question 7

what are causes for medical errors *

Answer 7

a lot have cognitive involvement

Question 8

extent od diagnositic errors

Answer 8

they account for:

the largest fraction of claims

the most severe pt harm

the highest total of penalty payouts - $38.8 billion between 1986 and 2010

Question 9

what is the process of clinical decision making *

Answer 9

rare to use formal computations

instead clinical judgement is a combination of heuristics and probabilities

heuristics are rules of thumb, educated guesses and mental shortcuts

good in urgent situations - quick, heuristics are based in pt data and prev patients make decisions subconsciously by pattern recognition

Question 10

what are the 2 systems for decision making*

Answer 10

hot system - system 1

cold system - system 2

Question 11

describe system 1 for making decisions *

Answer 11

emotional

'’go’’

simple

reflex

fast

develops early

accenuated by stress

stimulus control

without reflection

Question 12

describe system 2 for decision making *

Answer 12

cognitive

'’know’’

complex

reflextive

slow

develops late

attenuated by stress

self control

builduing info together

Question 13

which system for decision making is better *&

Answer 13

need both

Question 14

describe context in decision making *

Answer 14

dependant on the situation - if urgent action needed system 2 is not going to be effective - need system 1

Question 15

eg of when we ahve to override system 1 with system 2 *

Answer 15

when we have seen illusions before - system 1 tells us that 1 line is shorter than the other

system 2 tells us from experience that they are both the same length

Question 16

describe Nisbett and Wilson’s study *

Answer 16

consumer study in shopping mall

4 pairs of tights in a row and consumer had to decide which they liked the best

consumers were significantly more likely to pick far R pair - even though all identical and positioon of tights was chosen and changed randomly

teh consumers could provide justification, and when it was suggested that their choice was becasue the tights were on the R they opposed this

system 1 controlled the choice (R hand dominance) system 2 was blissfully unaware - thinking it was in charge - 1 made the choice and 2 makes rationale after event

Question 17

describe conformatory bias *

Answer 17

the tendancy to seek interpret and recall info in a way taht confirms one’s preexisting beliefs or hypothesis, often leading to errors

eg looking for evidence that supports your choice to remain in brexit

Question 18

how does conformatory bias relate to clinical practice *

Answer 18

possibly to blame for ineffective medical procedures that were used for centuries before the arrival of modern medicine - leeching and blood letting - only found evidence that supported this

when evaluating a diagnosis have to test for alternatives - not just things that would confirm your hypothesis

Question 19

describe the overconfidence in medicine *

Answer 19

podbregar and collegues studied 126 patients who died in ICU- did autopsy so could determine the diagnosis

physians were asked to provide the clinical diagnosis and their level of uncertainty on it

clinicians who were completely certain of the diagnosis ante-mortem were wrong 40% of teh time

Question 20

what can explain overconfidence in medicine I*

Answer 20

confirmatory bias

Question 21

why is it understandable that physicians have overconfidence

Answer 21

hard to manage the demand of making decisions, so if you were not confident, you would be anxious all the time and not function

Question 22

describe the sunk cost fallacy *

Answer 22

future outcome depends on what we have done so far

sunk costs are any costs that have been spent on a project taht are irretrievable eg money spent building a house and drugs used to treat pt with rare disease

thought process is that you cant give up treating the pt now with the expensive drugs - however they really need a new treatment

Question 23

how should we make decisions with respect to the sunk cost fallacy &*

Answer 23

rationally - only factor affecting future action should be future cost-benefits ratio

but humans dont always act rationally - the more we have invested in the past, the more we are willing to invest in the future

Question 24

study illustrating whether sunk cost fallacy exists in decisions *

Answer 24

bornstein et al

evaluation of clinical decisions were not influenced by sunk costs

however they did express a sunk cost effect in non-clinical decisions

Question 25

describe anchoring *

Answer 25

heuristic

cognitive bias

initial starting point determines deviation from starting point eg in sales

individuals are poor at adjusting estimates from a given starting point

adjustments are crude and imprecise

`

Question 26

clinical effect of anchoring *

Answer 26

initail idea for diagnosis serves as the anchoring point eg acute pancreatitis

but if later symptoms/history reveal no alcohol intake and tests show normal level of panc enzymes

clinicians may dismiss or excuse conflicting data - eg the pt is lying/underestimating alcohol, his panc is burned out and lab has made a mistake)

Question 27

how is probability involved clinically *

Answer 27

many clinical situations involve making decisions on the basis of prob

eg 2 competing diagnoses, alternative treatments

more complicated than give credit for

Question 28

describe representiveness heuristic *

Answer 28

subjective probability that a stim belongs to a particular class based on how ‘typical’ of that class it appears to be - regardless of base rate probability

can result in neglect of relevant base rates and otehr errors

Question 29

describe how representiveness heuristic can cause errors*

Answer 29

eg a 60yr old woman has no known med problems, now looks and feels well, reports erlier symptoms of feeling sick, sweaty, clammy, SOB, feeling faint

this doesnt match typical MI which is characterised by chest pain

but unwise to dismiss MI becasue it is common among women of that age and has highly variable presentations - women present differnetly to men

Question 30

how do you assess conditional probabilities *

Answer 30

a women presents with a lump in her breast - from age and previous records you estimate risk iof cancer is low - 1%

you send her to radiologist for mammogram and radiologist says mammogram is +ve - indicating cancer

if 1000 people testing - using baseline risk of cancer - 990 dont have cancer and 10 do - there are 80% true positives and 10 percent false positives

therfore 99 false positives and 8 true positives using the baseline chance of 1%

therefore only have 8/107 = 7.5% chance of having cancer

Question 31

explain how the framing effect can influence clinical decison making *

Answer 31

we have an aversion to loss - so if something is loss framed we are less likely to make that choice

eg 200/600 will survive on a treatment or 1/3 probability 600 will live and 2/3 prob none will be saved

• likely to choose treatment that saves 200

400/600 will die with treatment or 1/3 prob no people will die but 2/3 prob all 600 will die

• more likely to choose 2nd because we dont want to choose option that involves loss of 400 lives

Question 32

how is framing affected by age *

Answer 32

when presented with treatment options described in postive, negative or neutral terms - older adults are more likely to agree with treatment when positively described

effect stronger in older adults

Question 33

describe teh availability heuristic *

Answer 33

probabilities are estimated on the basis of how easily and/or vividly they can be called to mind

people heavily weigh judgements towards more recent info

individuals overestimate freq occurance of catastrophic events as cause of death compared to strokes etc

Question 34

how can the availability heuristic affect clinical decisions *

Answer 34

a clinician who recently missed teh diagnosis of an PE in young women with chest discomfort but no other symptoms or risk factors might overestimate PE in similar cases - ordering more CT angiographies - cause further errors

Question 35

what are the things that can be done to improve clinical decision making *

Answer 35

education and training

feedback

accountability

generating alternatives

consultation

understand and apply statistical principles eg law of large numbers- greater confidence can be

Question 36

describe how ed and training improves decisions *

Answer 36

integrate teaching about cignitive error and diagnostic error into med school curricular

recognise that heuristics and biases might be affecting judgement even though we might not be conscious of them

reflect on our decisions and what has lead to them introduces a buffer for these errors

Question 37

how does feedback improve decisions *

Answer 37

increase number of autopsies - learn from previous decisions - brain bank for dementia where there is a lot of diagnostic uncertainty

conduct regular and systematic audits - see if patterns at certain times/clinics

follow up pts - se if you were right

Question 38

how would accountability improve decision making*

Answer 38

establish accountability and follow up for decisions made

give more weight

Question 39

how does generating alternatives improve decision making *

Answer 39

establish forced considertion of alternative possibilities - eg the generation and wroking through a ddx and looking for evidence for different possibilities

encourage routinely asking the qn - what else might this be

Question 40

how would consultation imprve decision making*

Answer 40

seek second opinions

use algorithms - for probability calculations

use of clinical decision making support systems - AI - fuse large amounts of data

Question 41

how do algorithms help decision making *

Answer 41

an algorithm is a procedure that if follwed exacltly will provide the most likely ans based in evidence

the rules of probability are eg of algorithms

most useful when problem is well defined - excludes many everyday decisions

people have to be taught how to use them

gets complicated when people have inconsistant symptoms and co-morbidities

Question 42

describe clinical decisiom making support systems*

Answer 42

include a lot of info at any time

wont replace clinical decision making - art of medicine

but will be better at calculating probability

Question 43

gambler’s fallacy

Answer 43

a logical fallacy involving the mistaken belief that past events will affect future events when dealing with random activities, such as many gambling games.