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The Problem of Knowing

Posted on April 3, 2013 6:34 am by dave Comment

What creates that feeling that we know something?

A simple thought experiment.

It is “Fathers of Daughters” day in the park.
Only men with daughters are allowed.
One of these men asks you, “I have at two children, one is a girl, what is the probability that my other child is a girl?”
Assuming equal birth frequencies, it would seem obvious that the chance is 50:50 that his other child is a girl.

Why does this answer feel correct?
When, in fact, it is wrong!
You can scroll down the page for the explanation and some variations on this “cognitive illusion”.

It is similar an optical illusion.

Both A and B squares are identical shades of grey.

Somehow we feel OK about an optical illusion, perhaps because we can cover up the other squares and prove it is an illusion.
But we may remain argumentative about a cognitive illusion, perhaps because it challenges the very mechanism we are using to make judgements.

Why does this matter?
We (and our patients) are at our must vulnerable when we are convinced we know, when we are attached to a belief.
This is called “task fixation” in airline crash investigation.

This is another characteristic of “being in the world” (In-der–Welt–sein) that is “made sense of” by “dual process theory”.

This is an eloquent exposition

Or perhaps, if you still think you are in control of your own thoughts

More on the father daughter problem

The man in the park is drawn from a very special population.
Families with at least one girl.
Assuming an equal frequency of births then the following patterns are equally possible.
Girl Girl, Boy Girl, Girl Boy.
So the probability of having met a man with 2 girls is 1 in 3

Let us say that you are walking home from the park and you meet another man, walking with a girl.
He tells you, “I have two children, one of whom is a girl” and asks, “What is the probability that my other child is a girl?”
There is debate on the answer to this question, although the majority favour 1 in 3

He tells you, “I have two children, this girl is my daughter”, and asks “What is the probability that my other child is a girl”
Now our instinct is correct, the probability is 1 in 2.
He is drawn from a population of men walking a daughter,
assuming walking with a child of either sex is equally likely.
Assuming that the first-born child has an equal probability of being a girl or a boy &
the second-born child has an equal probability of being a boy or a girl
The population from which the father and daughter combination is drawn is now
First-born child girl walking, second-born child girl at home
Second-born child girl walking, first-born child girl at home
First-born child girl walking, second-born child boy at home
Second-born child girl walking, first-born child boy at home

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The Ageing Anaesthetist

Posted on April 3, 2013 6:30 am by dave Comment

Just tap me on the shoulder,
when it’s time for me to go

Introduction

Since 1970, the percentage of the population below 14 has dropped over 30% while the percentage of population between the ages of 65 and 85 has increased by 50%.  In Victoria, almost one in six registered medical practitioners are over 60 years of age[1].   The Global Financial Crisis and subsequent collapse of superannuation funds have delayed our plans for retirement.  This has provided a convenient excuse to postpone that uncomfortable retirement day.  The day we give up the purpose and social circle provided the most rewarding career we could have imagined.  But our cognitive clocks are ticking.  How can we be sure that we do not outstay our welcome? To answer this question we need to know how cognitive function & performance change with age.  We should consider our responsibilities to our patients, our colleagues and the law.  Then we will be better placed to incorporate age related changes into our life own plans.

From normal ageing to the dementias

Our cognitive spectrum can be summarised into 10 broad (stratum 2) abilities.   One of these improves with age.  It is referred to as “crystallised intelligence” and encompasses verbal skills, long-term memory, and the implicit memory necessary for intuitive or expert problem solving.   Four abilities decrease with age.  They are fluid intelligence, processing speed, short-term memory and its related working memory.[2] Their loss affects planning, abstraction and cognitive flexibility. This leads to a tendency to rigid and concrete thinking. It is worsened when cognitive resources and resilience are decreased by stress & fatigue.  Automated, expert, instinctive practice is preserved but the ability to “think on ones feet” or react to a novel situation are compromised.  A doctor may still excel in familiar daily clinical practice but stumble at night when an unanticipated, novel, emergency occurs. (Figure 1)

Figure 1.  Comparative graph of the effects of age on fluid and crystallised intelligence.  The black line represents general IQ.

Mild cognitive impairment is a diagnosis given to individuals whose cognitive impairment is beyond that expected for their age and education. The predominant symptom is usually memory loss. It is considered to lead to a form of dementia when the progressive loss of intellectual and social skills becomes severe enough to interfere with day-to-day life.  The dementias are typically irreversible, and rarely treatable to the point of cure or arrest.  They are a jumble of interrelated brain disorders that are variously named and differentiated by eponym, symptoms, histopathology, or anatomic location.  Of most concern for professional practice are Alzheimer’s disease, because it is common, and frontal syndrome, because it is often associated with lack of insight.

Legal aspects of ageing

The overwhelming majority of doctors self determine the end of their career before their practice is compromised.  For those that work on, memory failure is often the first sign of that alerts the individual, their family or colleagues.  There are commercial enterprises to help with the diagnosis if you keep forgetting your keys, anniversary or birthday.  Take the test for $10, or buy the book for $30 and get a dementia test free![3]

There are self-reporting obligations under the legislation behind the Australian Health Practitioner Regulation Agency (AHPRA).  Annual online registration mandates disclosure of any impairment or restriction of practice rights secondary to health, conduct or performance.  Furthermore, registrants are required to give written notice within 7 days if practice rights are withdrawn or restricted.

A doctor may also come to AHPRA’s attention following a patient complaint or injury.  AHPRA delegates much of this operational work to the federal and state Medical Boards.  The review process usually starts with a local “notification assessment committee” that performs a preliminary investigation.  If necessary, the matters are then passed on to an assessment committee (health or professional conduct).  If a “health assessment committee” determines there may be significant health impairment then a review panel is convened to take the relevant action.  The final tier is the Medical Tribunal, reserved for issues of significant misconduct or appeals against decisions made at lower tiers.  This not a therapeutic system, although it does provide a point of contact with potentially impaired doctors.

What do medical boards uncover?  Between 2000 and 2006, there were 70 notifications to the health committee of NSW medical board concerning doctors over the age 60.  41 of these doctors were determined to have impairment affecting their capacity to practice as defined by the Act.  As in younger groups, the 3 D’s of depression, drugs and drink were found in the majority of cases.  This older group added the 4^th D of dementia with 21 (54%) demonstrating mild cognitive impairment.  Five doctors (12%) were still practicing with frank dementia![4]

Medical practitioners have a professional responsibility, born of respect, for colleagues who might lack insight into failing performance and an ethical responsibility towards their patients. Finally there are legal obligations covering the four main areas of mandatory notification; Practicing while intoxicated, Sexual misconduct, Performance that places the public at substantial harm, An impairment that places the public at risk of substantial harm[5].

A doctor is only required to notify AHPRA if they form their belief while practicing their profession.  This does not apply if the belief was formed as part of certain legal processes or within a quality assurance committee authorised under an appropriate act.  It should also be noted that not reporting does not constitute an offence under the act but action may be taken[6].

There are numerous barriers to reporting colleagues.  Detecting subtle cognitive impairment of an older, articulate physician is often difficult.  As noted earlier, verbal ability is well preserved, so subtle cognitive changes may be difficult to recognise.  Practitioners are less likely to be detected if they work alone or have a low caseload.  There may the misguided “protection” by family or colleagues out of respect for the doctor’s contribution to the profession or the community.  It is clear however, that allowing someone to practice until their reputation is tarnished or a patient is harmed, does not constitute an act of respect.  It is more likely to represent avoidance of a potentially unpleasant confrontation.

Mandatory retirement ages and screening programs offer a way of avoiding the conflict that can arise when singling out a practitioner.  Airline pilots must undergo annual health and performance checks to ensure that passengers can have confidence in those who fly their aircraft.  Commercial airline pilots have a mandatory retirement age of 65.  In Australia, judges are required to retire from full-time judicial duties after the age of 70 years.     In Alberta, Canada, there is a Physician Achievement Review program that is a combined quality improvement and registration program.[7] Every 5 years doctors hand questionnaires to patients, medical colleagues and non-medical co-workers.  They cover multiple topics, matched to the specialty and reporting group.  These topics range across many areas of practice, including medical competency, communication skills, and office management.   In return, the doctors receive a “report card” that shows their individual score on each topic within the band of scores achieved by their peers.  Doctors scoring in the lowest percentile in a topic are provided with the “opportunity” for a personal review of the identified issue.

The College of anaesthetists document PS 16 on standards of practice notes “review by appropriately skilled colleagues may be a necessary part of the decision to continue in professional practice.[8] But it does not provide any guidance on how to implement this recommendation.  Sed quis custodiet ipsos custodes? (Who guards the guardians?)[9]

Transitioning to retirement

Declining Fluid intelligence decreases our ability to react quickly in unfamiliar circumstances or emergencies.  This is made significantly worse when our reserve is diminished by the HALTS factors; Hungry, Angry, Lonely, Tired, Stressed.  Fatigue can be compounded by the decrease in sleep efficiency with age.  The challenge is to find a balance point between reducing hours and maintaining standards.  Strategies include avoiding night shifts (alone & tired) and avoiding weekend shifts (working alone).  There are opportunities to expand interests, beyond acute clinical service delivery, into administration, research or teaching.  Senior doctors have the wisdom of time and experience to support their profession through their colleges or broader medical organisations such as medical unions and associations.  The Welfare of Anaesthetists Special Interest Group provides a useful document on retirement and late career options for the older professional. [10]

A smooth transition requires more than simply setting a date and obtaining sound financial advice, it requires intentional planning of future life goals and roles. Successful transition will also include the development of broader interests outside medicine.  These strategies will also alleviate cognitive decline.  As Grace Slick sang in the sixties “Remember what the dormouse said, feed your head”.  In particular we need to maintain cognitive, physical and social activity.  Playing Sudoku is not sufficient!  It is important to control vascular risk factors, in particular through diet. Finally, every doctor should have a general practitioner skilled in looking after doctors.  This independent practitioner is more likely to recognise and treat depression, which can enter by stealth, in times of change, and mimic or worsen cognitive decline.

Retirement should provide the opportunity to engage Erikson’s 8^th stage of development, “Late Adulthood”, with integrity rather than despair.  To reflect on a world that has meaning and our contribution through career and family.  Then our perspective may broaden, and attachments loosen their grip, as we prepare for the next transition.[11]

1.         Adler, R.G. and C. Constantinou, Knowing – or not knowing – when to stop: cognitive decline in ageing doctors. Med J Aust, 2008. 189(11-12): p. 622-4.

2.         Christensen, H., What cognitive changes can be expected with normal ageing? Australian & New Zealand Journal of Psychiatry, 2001. 35(6): p. 768-775.

3.         http://mindcheck.com.au.

4.         Peisah, C. and K. Wilhelm, Physician don’t heal thyself: a descriptive study of impaired older doctors. Int Psychogeriatr, 2007. 19(5): p. 974-84.

5.         Health Practitioner Regulation National Law (South Australia) Act [1.10.2012], in Definition of Notifiable Conduct [140-2]2010.

6.         Health Practitioner Regulation National Law (South Australia) Act [1.10.2012], in Mandatory notifications by health practitioners[141-2]2010.

7.         http://www.par-program.org/.

8.         Australian & New Zealand College of Anaesthetists. PS 16 Statement on the Standards of Practice of a Specialist Anaesthetist. 2008; Available from:http://www.anzca.edu.au/resources/professional-documents/documents/professional-standards/professional-standards-16.html.

9.         Fenwick, D.G., Knowing – or not knowing – when to stop: cognitive decline in ageing doctors. Comment. Med J Aust, 2009. 190(8): p. 464.

10.       Welfare of Anaesthetists Special Interest Group. Retirement and Late Career Options for the Older Professional. 2011.

11.       Erikson, E.H., The Life Cycle Completed. Extended Version with New Chapters on the Ninth Stage of Development by Joan M. Erikson. W1997.

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Dual Process Theory in the Operating Theatre

Posted on April 3, 2013 6:22 am by dave Comment

Introduction

“Dual process” theories seek to reconcile the traditional dualisms of mind and body (Descartes)[1], conscious and non-conscious mind(Freud)[2].   This has provided new perspectives on the practice and teaching of medicine. This article will briefly review dual process theory and an example of its implementation in surgery.

History of Dual Process Theory

In 1975, Wason and Evans suggested two processes of reasoning were needed to explain the results of the “Wason card selection test”.[3] The conscious reasoning of their subjects did not match the unconscious bias that actually directed their behaviour. This was similar to an expert physician who provides an accurate diagnosis while the explanation for that diagnosis suggests post hoc rationalisation.[4]

Daniel Kahneman summarised evolving characteristics of the two systems in his acceptance speech for a Nobel Prize in 2002.[5] The oldest system, in an evolutionary sense, is System 1, which is slow to learn but fast, automatic and effortless to execute. System 1 is context dependent and bound to the emotional centres that activate it. System 1 is outside direct consciousness, its existence inferred from biases and attitudes. System 2 is more recently acquired. At first glance it is the poor cousin, being slower, effortful and relatively easily overwhelmed, particularly when an individual is stressed in other ways. (Hungry, angry, late, or tired). The advantage of System 2 is its flexibility; rules can provide decisions and judgements in new situations where the novel context cannot generate a System 1 solution. System 2 may also contain metacognitive functions such as selecting the most appropriate processing system for a given circumstance.

It is important to understand that these systems work in parallel, not in opposition. System 1 is responsible for the “heavy lifting”, directing the majority of our behaviour. System 2 is the “icing on the cognitive cake”. It is all that we see on first introspection. As a result we make the reasonable, but incorrect, assumption that it is the primary control centre. Like the icing on the cake, System 2 cannot support itself without the lower centres to give it form. Nearly all “rational” decisions require input from emotional centres attributing “weight” to the various alternatives. Even the “feeling of correctness” that we use to accept the final solution rises from the subconscious realms of system 1. [6]

Slowing down When You Should

Expert practice entails a fluid coordination of system 1 and system 2 processes.[4] A significant proportion of clinical errors in medicine or surgery may be traced to the inappropriate use of system 1 or 2 processes in a given circumstance. These are included in the “human factors” deemed responsible for the bad things that happen to the patients of good practitioners. Examples include “task fixation”, loss of “situational awareness”, and bias. Programs are being developed to provide specific training in the reflective skills needed to avoid these pitfalls. [7]

Carol-Anne Moulton has characterised the System 2 process in surgery as “slowing down”. [8] This occurs when the surgeon moves their cognitive emphasis from automatic to effortful. Observed behaviours ranged from increasing attention to the task in hand, decreasing extraneous information by minimising distractions (the “sterile cockpit”), through to stopping altogether and re-evaluating the situation. “Slowing down” moments may be planned preoperatively or occur in response to environmental factors such as unanticipated anatomy or difficulty with exposure.   Experienced surgeons identified these behaviours in them-selves even though they used different metaphors.

There is value in making the act of “slowing down” explicit. It is useful for surgical trainees to be briefed on the critical moments in a surgical procedure. It helps other members of the theatre team to optimally support the surgeon, recognising moments requiring a higher level of concentration. During these times of surgical focus the surgeon may lose more general “situation awareness”. The remaining staff need be more vigilant and have agreed methods of escalating concern if other issues emerge.

Conclusions

There are a number of valuable lessons that can be drawn by constructing our understanding of expert medical practice around dual process theory. We can appreciate the distinct and uniquely valuable contributions of both art and science. This can guide our approach to medical education, emphasising the relative importance of didactic teaching, apprenticeship and simulation. It can help delineate vulnerabilities specific to different modes of reasoning and problem solving.

1.         Damasio, A.R., Descartes’ error : emotion, reason, and the human brain2005, London: Penguin. xxiii, 312 p.

2.         Wilson, T.D., Strangers to ourselves : discovering the adaptive unconscious2002, Cambridge, Mass.: Belknap Press of Harvard University Press. viii, 262 p.

3.         Wason, P.C. and J.S.B.T. Evans, Dual processes in reasoning? Cognition, 1975. 3: p. 141–54.

4.         Croskerry, P., A universal model of diagnostic reasoning. Acad Med, 2009. 84(8): p. 1022-8.

5.         Kahneman, D., A perspective on judgment and choice: mapping bounded rationality. Am Psychol, 2003. 58(9): p. 697-720.

6.         Burton, R.A., On being certain : believing you are right even when you’re not. 1st ed2008, New York: St. Martin’s Press. xii, 256 p.

7.         Non-Technical Skills for Surgeons (NOTSS). Available from: http://www.surgeons.org.

8.         Moulton, C.A., et al., Slowing down when you should: a new model of expert judgment. Acad Med, 2007. 82(10 Suppl): p. S109-16.

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