Incorporating Mechanism Maps in Teaching A Strategy for Enhancing Critical Thinking

Incorporating Mechanism Maps in TeachingA Strategy for Enhancing Critical Thinking

Jeremy B. Richards, MD, MA

Richard M. Schwartzstein, MD

Shapiro Institute for Education and Research

Beth Israel Deaconess Medical CenterHarvard Medical School

A teaching hospital of

Harvard Medical School

Education is at the heart of patient care.

A teaching hospital ofHarvard Medical School

Disclosures – Dr. Schwartzstein• Perspectives advisory board, New England Journal

of Medicine• Editorial board, Chest• NIH funding for dyspnea research

Disclosures – Dr. Richards• CRICO funding for quality improvement research


Today’s Goals• Review cognitive science underlying the

development of durable learning• Delineate the dual system model of how we think

when approaching new problems • Describe the role of inductive reasoning in critical

thinking• Demonstrate the difference between classical

concept maps and mechanisms maps• Have you develop a mechanism map


What is critical thinking?


What does “work the problem” look like?


How we think…Dual Processing

• Conscious thought• Unconscious thought

– Cognitive Biases


Judgment Under UncertaintyTversky and Kahneman, Science, 1974

“…people rely on a limited number of heuristic principles which reduce the number of complex tasks of assessing probabilities…to simpler judgmental operations” which can “lead to severe and systemic errors.”


Pattern Recognition

Repetition

Executiveoverride

Dysrationaliaoverride Calibration DX

PatientPresentation

PatternProcessor

RECOGNIZED

NOTRECOGNIZED

Type11

Processes

Type22

Processes

Dual ProcessingCourtesy of P. Croskerry, MD, Millennium Conf 2011


Retention and Use of Knowledge• Long term memory develops in three phases

– Information presentation**– Information processing– Information integration**

• How do you teach?**– Do you look for frameworks for the knowledge to

be learned?– Do you build on prior learning?


How do students/residents learn?Modified from Harasym et al. 2008

Surface Learning-- New info not linked to

previous knowledge-- Knowledge abundant but

disorganized-- Focus on memorization

and recall-- Learns concepts and facts

without reflection

Deep Learning-- Relates new knowledge to

previous knowledge-- Content organized into

coherent whole-- Focus on problem-solving;

apply, analyze-- Link concepts/principles to

everyday experience


Deep vs. Superficial Learning

• Link new information to prior learning

• Create frameworks to help students organize and use knowledge

• “Understanding” beyond “knowing”


Routine vs. Adaptive Expert Mylopoulos M, Regehr G. Med Ed 2007

• Routine Expert – Novel problem adapt problem to the

solution with which they are comfortable– Characterized by speed, accuracy, automaticity

• Adaptive Expert– Use a new problem as a point of departure for

exploration; expand knowledge and understanding

– Characterized by innovation, creativity


Expertise and Creativity


How do you solve problems?

You put the key in the ignition, turn the key and the car doesn’t start.

What’s the answer? How do you think about this problem?


Thinking ApproachesModified from Pottier et al. Med Ed 2010

Inductive Reasoning Deductive Reasoning


Structure and Use of Traditional Concept Map


“Mechanism” Maps• Graphic devices to

represent relationships between multiple concepts

• Reinforce mechanistic thinking

• Make links explicit


Concept vs. Mechanism Map

Pancreatitis

Inflammatory response / cytokine Release

Increased vascularpermeability

Third-spacing Increased abdominalpressures

Decreased preload

Decreased CO

Decreased chest-wallcompliance

IncreasedADH

Increased Palv

Increased dead space

Decreased Na

Decreasedinsulin

Hypovolemia Increased glucose

Decreased DO2

Increasedsympathetic

activation

Increased HR

Increasedanaerobic

metabolism

Increasedlactate

Increased PaCO2

Hypotension

Acidemia

Acute kidneyinjury

Decreased calcium

Pancreatitis

Inflammatory response / cytokine Release

Increased vascularpermeability

Third-spacing Increased abdominalpressures

Decreased preload

Decreased CO

Decreased chest-wallcompliance

IncreasedADH

Increased Palv

Increased dead space

Decreased Na

Decreasedinsulin

Hypovolemia Increased glucose

Decreased DO2

Increasedsympathetic

activation

Increased HR

Increasedanaerobic

metabolism

Increasedlactate

Increased PaCO2

Hypotension

Acidemia

Acute kidneyinjury

Decreased calcium


Student Comments Support Mechanism MapsMajor themes:

1) Determine causality

“Concept maps helped me look a causality and connections between different parts of the clinical presentation.”

2) Helped identify weaknesses“Concept maps forced me to challenge my understanding

and helped me identify areas that needed more work.”3) Integrated knowledge

“Concept maps helped tie together constellation of symptoms and see how one physiological change can affect multiple organs or cause multiple symptoms.”

4) Helped develop hypotheses“Concept maps made me think of a broad array of causes

for a specific symptom.”


Mechanism Maps Enhance Exam Performance• Final Exam:

– Final exam was composed of 12 questions– Case-based exam; mostly paragraph answers– Focus of the exam – apply knowledge to solve problems– Maximum possible score = 182

• Overall – 156.0 (std. dev. 12.9) – Range 119-180.5• Group A – 157.5 (std. dev. 11.7)• Groups B and C – 152.3 (std. dev. 13.1)

F-statistic=3.34, p=0.07

priori level of significance of α=0.1.

Veronese et al. Med Teach, In press.

Students’ mechanism maps

Students’ mechanism maps


Summary• Teaching/learning that emphasizes conceptual

framework supports understanding and application of content

• Inductive reasoning may facilitate adaptive expertise

• Mechanism maps provide a strategy to reinforce basic concepts and teach students how to “work the problem”


Mechanism map examples• Topic- versus case-based concept maps


Case-based mechanism map76yo woman with ~10 years of steadily worsening dyspnea, who

now cannot walk more than half a block on flat ground due to breathlessness. She has smoked 10-20 cigarettes a day for 55 years. Recently, she has developed a productive cough and

wheezing. Her exam is notable for a temperature of 98.7, BP 122/84, HR 98, RR 18, O2 sat 90% on room air. Her chest has low-

lying diaphragms and is hyperresonant to percussion. She has decreased breath sounds and expiratory wheezes with an

increased anteroposterior diameter. Heart sounds are distant. Fingernails are not clubbed or cyanotic. She has a 2+ lower

extremity edema.


Case-based mechanism map

• Identify and highlight core signs and symptoms• Identify pathophysiologic and clinical mechanisms

that link these core signs and symptoms• Begin to link the core signs and symptoms using

pathophysiologic mechanisms• Use linking words when needed• Be open to opportunities to cross-link concepts or

expand the map in new directions


Case-based mechanism map76yo woman with ~10 years of steadily worsening dyspnea, who

now cannot walk more than half a block on flat ground due to breathlessness. She has smoked 10-20 cigarettes a day for 55 years. Recently, she has developed a productive cough and

wheezing. Her exam is notable for a temperature of 98.7, BP 122/84, HR 98, RR 18, O2 sat 90% on room air. Her chest has low-lying diaphragms and is hyper-resonant to percussion. She has

decreased breath sounds and expiratory wheezes with an increased anteroposterior diameter. Heart sounds are distant.

Fingernails are not clubbed or cyanotic. She has a 2+ lower extremity edema.


Case-based mechanism mapworsening dyspnea

smoked cigarettes

productive cough wheezing


Break-out groups• Time to put theory into practice!• Divide into groups of 4-5• Each group will spend the next 20 minutes designing a

mechanism map based on a case vignette• Highlight pathophysiologic mechanisms as they relate

to clinical signs and symptoms• During the process, keep track of pros and cons of

developing a mechanism map


Break-out groups?• Students were assigned to groups of 3 and instructed

to produce a consensus concept map in response to questions about microbiology

Kinchin I, Hay D. J Adv Nurs 2005;51(2):183–7

Morse D, Jutras F. CBE Life Sci Educ 2008;7(2):243-53

• Learning and performance was higher in students in groups with disparate backgrounds and different knowledge bases

• Peer (and instructor) feedback reinforces learning beyond the act of building a concept map


Break-out groups• Time to put theory into practice!• Divide into groups of 4-5• Each group will spend the next 20 minutes designing a

mechanism map based on a case vignette• Highlight pathophysiologic mechanisms as they relate

to clinical signs and symptoms• During the process, keep track of pros and cons of

developing a mechanism map


Case vignetteMr. Green, a 47yo attorney and former heavy drinker, presents

with a 6 month history of marked fatigue and dyspnea on minimal exertion. He tells you, “I feel so tired by lunch time that

I have to go home to sleep.” He has also had decreased exertion, and has cut his daily 2 mile walk to 1 mile, a half mile, and then stopped walking altogether. He cannot lie flat at night

because he awakens 1-2 hours after going to sleep with dramatic shortness of breath. Over the last two weeks he has

only been comfortable sleeping upright in a chair.


Case vignetteMr. Green, a 47yo attorney and former heavy drinker, presents

with a 6 month history of marked fatigue and dyspnea on minimal exertion. He tells you, “I feel so tired by lunch time that I have to go home to sleep.” He has also had decreased

exertion, and has cut his daily 2 mile walk to 1 mile, a half mile, and then stopped walking altogether. He cannot lie flat at night

because he awakens 1-2 hours after going to sleep with dramatic shortness of breath. Over the last two weeks he has

only been comfortable sleeping upright in a chair.


Physiologic mechanismsConsider using these concepts / mechanisms in your map:

•Preload•Afterload•Sympathetic nervous system•Contractility•Stroke volume•Heart rate

•Diastolic (volume, pressure)•Systolic (volume, pressure)•Systemic vascular resistance•Oxygen delivery•Gas exchange•Hypertrophy

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Incorporating Mechanism Maps in Teaching A Strategy for Enhancing Critical Thinking