Clinical Decision Making Flashcards
What is an error?
the failure of a planned action to be completed as intended (i.e., error of execution) or the use of a wrong plan to achieve an aim (i.e. error of planning)
For example:
- Incorrect diagnosis
- Failure to employ indicated tests
- Error in the performance of an operation, procedure, or test
- Error in the dose or method of using a drug
What is an example of a medical error due to obedience and hierarchy?
He became paralysed and almost a month later his parents agreed to turn off his life support machine
Mr WJ was diagnosed with acute lymphoblastic leukaemia in 1999 aged 15
June 2000, he still needed 3-monthly injections of 2 chemotherapy drugs: Vincristine (IV) and Cytosine (IT)
On 4th January 2001, WJ was mistakenly given Vincristine intrathecally
Similar errors involving Vincristine had been made 14 times in Britain since 1985 - 11 resulted in death the other 3 in paralysis
The registrar involved was convicted of manslaughter and sentenced to 8 months imprisonment
*The SHO understood that this isn’t the correct procedure, but didn’t want to challenge his senior registrar colleague. This is consistent with studies that suggest that we suspend critical judgement, if we feel that the responsibility is taken by a higher authority
NURSE-DOCTOR RELATIONSHIP
- Researchers placed a fictional drug in the ward drug cabinet
- The label clearly stated: ‘Maximum Dose 10mg’
- ‘Dr Smith’ rang the ward and asked nurse to administer 20mg, and he would sign for it later
- 21 out of 22 nurses prepared the dose
What are causes of medical errors?
- both system-related and cognitive factors
- cognitive error only
- system-related error only
- no-fault factors only
*One hundred cases of diagnostic error were evaluated to identify system-related and cognitive factors underlying error using record reviews. The majority of cases had an aspect of cognitive error. There seems to be something wrong with the thinking error. Diagnostic error can be very serious (especially on the acute wards, where decisions about diagnosis need to be made quite quickly). There are strong cognitive aspects contributing to diagnostic error.
What is involved in clinical decision making?
- Clinicians rarely use formal computations to make patient care decisions in day-to-day practice
- Intuitive understanding of probabilities is combined with cognitive processes called heuristics
- Heuristics guide clinical judgment
- Heuristics are often referred to as rules of thumb, educated guesses, or mental shortcuts
- Heuristics usually involve pattern recognition and rely on a subconscious integration of patient data with prior experience
What are the systems for decision making?
“hot” system (system 1):
- emotional
- “go”
- simple
- reflexive
- fast
- develops early
- accentuaed by stress
- stimulus control
“cold” system (system 2):
- cognitive
- “know”
- complex
- reflective
- slow
- develops late
- attenuated by stress
- self control
*Our system 2 allows us to overcome our system 1 when interpreting optical illusions
** Nisbett and Wilson (1977) - picking tights
What is confirmation bias?
The tendency to search for or seek, interpret, and recall information in a way that confirms one’s pre-existing beliefs or hypotheses, often leading to errors
People tend to seek information that CONFIRMS their view. For example, people who voted to leave the EU would tend to want to read newspapers that SUPPORT Brexit
This can be risky in diagnostic terms: our initial diagnostic ideas are the ones that we investigate. We may ignore investigations that contradict our diagnoses, and on
What’s a case study for over-confidence in medicine?
Podbregar and colleagues studied 126 patients who died in the ICU and underwent autopsy
Physicians were asked to provide the clinical diagnosis and also their level of uncertainty
Clinicians who were “completely certain” of the diagnosis ante-mortem were wrong 40% of the time
What is sunk cost fallacy?
Sunk costs are any costs (not necessarily financial) that have been spent on a project that are irretrievable ranging including anything from money spent building a house to expensive drugs used to treat a patient with a rare disease.
Rationally the only factor affecting future action should be the future costs/benefit ratio but humans do not always act rationally and often the more we have invested in the past the more we are prepared to invest in a problem in the future, this is known as the Sunk Cost Fallacy.
- Bornstein et al (1999) found that medical residents’ evaluation of treatment decisions were not influenced by the amount of time and/or money that had already been invested in treating a patient. However, the residents did demonstrate a sunk-cost effect in evaluating non-medical situations.
E.g. If you pay to go to the cinema, but you’re not enjoying the film, you may be reluctant to leave and enjoy your evening elsewhere because you have ALREADY PAID for your cinema ticke
What is anchoring?
What is the anchoring effect?
Retailers take advantage of anchoring by telling you the ‘was’ price as well as the ‘offer’ price
They may also tell you its £69.99 instead of £70.00, because you are more likely to be influenced
Individuals are poor at adjusting estimates from a given starting point (probs. & values)
Adjustments crude & imprecise - anchored by starting point
Anchoring Effect
- A working diagnosis of acute pancreatitis may seem quite reasonable in a 60-yr-old man who has epigastric pain and nausea, who is sitting forward clutching his abdomen
- However, the patient states that he has had no alcohol in many years and investigations show normal blood levels of pancreatic enzymes
- Clinicians may simply dismiss or excuse conflicting data (e.g. the patient is lying, his pancreas is burned out, the laboratory made a mistake)
What is representativeness heuristics?
Subjective probability that a stimulus belongs to a particular class based on how ‘typical’ of that class it appears to be (regardless of base rate probability)
While often useful in everyday life, it can also result in neglect of relevant base rates and other errors
How do you assess conditional probabilities?
Bayes’ theorem
What is the availability heuristic?
Probabilities are estimated on the basis of how easily and/or vividly they can be called to mind
Individuals typically overestimate the frequency of occurrence of catastrophic, dramatic events
E.g. surveys show 80% believe that accidents cause more deaths than strokes
People tend to heavily weigh their judgments toward more recent information
How can decision making be improved?
- Education and Training
- Integrate teaching about cognitive error and diagnostic error into medical school curricula
- Recognise that heuristics and biases may be affecting our judgement even though we may not be conscious of them - Feedback
- Increase number of autopsies
- Conduct regular and systematic audits
- Follow-up patients - Accountability
- Establish clear accountability and follow-up for decisions made - Generating alternatives
- Establish forced consideration of alternative possibilities e.g., the generation and working through of a differential diagnosis.
- Encourage routinely asking the question: What else might this be? - Consultation
- Seek second opinions
- Use of algorithms
- Use of clinical decision making support systems
What are algorithms?
Algorithm: a procedure which, if followed, will provide the most likely answer based on the evidence
The rules of probability are examples of algorithms
Algorithms are most useful in situations where the problem is well defined -this excludes many everyday decisions
For the most part, people have to be taught how to use them
