Critical Thinking Richard M. Schwartzstein, MD Executive Director, Carl J. Shapiro Institute for Education and Research Faculty Associate Dean for Medical Education Professor of Medicine Harvard Medical School

Critical Thinking Do you do it?

Critical Thinking Do you do it? Do you teach it?

Critical Thinking Do you do it? Do you teach it? What is it?

Critical Thinking Do you do it? Do you teach it? What is it? What is the relationship between “critical thinking” and “clinical reasoning?”

Who is this? (How do you know?)

Who is this?

Who is this? (How do you know?) Political leader of the 20th century. Mother was American, father was British Lost election after leading his country to victory in war Fancied whiskey

Case A 60 year old man presents with a complaint of shortness of breath that has gradually worsened over 2 years. Now can only walk for 50 yards at which time he stops with a sensation of “suffocating” and “urge to breathe.” His wife notes “wheezing” when this happens.

Case, cont. PH: asthma since childhood, hypertension for 30 years, mild diabetes, 30 pack year smoker PE: obese. BP 160/90, HR 92, RR 16 Mild increase in AP diameter of chest. Lungs with mild decrease in air movement, I/E=1/1.5; JVP=10 cm. +S4. Abdomen benign. No edema. Thoughts? What next?

Case, cont. Walk the patient: After 50 yards, breathing starts to become labored, patient appears diaphoretic, chest exam: wheezes. Diagnosis?

Cardiac Asthma Increased PCWP  interstitial edema, Dyspnea Mechanical load Hypoxemia J-receptors Vascular receptors “urge to breathe,” “suffocating”

Diastolic Dysfunction 1/3 of cases of CHF are due primarily to diastolic dysfunction Failure of LV to accommodate increased volume load Symptoms often isolated to exercise

QUESTION Is the patient an example to be learned or a problem to be solved?

QUESTION Is the patient an example to be learned or a problem to be solved? Pattern recognition = experience-based, non analytical reasoning Norman G, Young M, Brooks L. Med Ed 2007

Primacy of Teaching Objectives If “critical thinking” is one of our objectives, we have to understand what implications that has for our interactions with students and residents.

Critical Thinking Plan of Attack Define the elements of critical thinking Distinguish critical thinking from clinical reasoning Delineate strategies for developing critical thinking in our learners.

Critical Thinking Plan of Attack Define the elements of critical thinking Distinguish critical thinking from clinical reasoning Delineate strategies for developing critical thinking in our learners. Caveat: this is a work in progress…

Hierarchy of Knowledge Bloom’sTaxonomy, 1956 Knowledge - What is the most common cause of...? Understand - If you see this, what must you consider…? Application - In this patient, what is causing…? Analysis,synthesis,evaluation - critical thinking?

Revision of Bloom’s Taxonomy Anderson LW, Krathwohl DR (eds), 2001 Revision of Bloom’s Taxonomy Anderson LW, Krathwohl DR (eds), 2001. A taxonomy for learning, teaching and assessing: A revision of Bloom’s taxonomy of educational objectives. New York, Longman.

What is an expert? Mylopoulos M, Regehr G. Med Ed 2007 Expertise = Knowledge + Experience Experts develop “rich and well organized resources…to effectively and efficiently solve routine problems of practice.” “Only some experts go beyond routine competencies and display flexible, innovative abilities…in a process of extending their knowledge rather than applying it.”

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

Critical Thinking Is the KSA model appropriate? Are there specific: Knowledge/facts Skills Attitudes …that must be acquired in order for the learner to become a critical thinker?

Knowledge Content learned in a conceptual framework How do the facts fit together? What are the underlying mechanisms? What do you do when the patterns break down? Content learned in a conceptual framework

Knowledge Content learned in a conceptual framework Judge credibility of sources From primary sources to “Google it…” Primary sources Study design Appropriate population Statistics Secondary sources Textbooks Review articles Evidence-based medicine

Knowledge Content learned in a conceptual framework Judge credibility of sources Bias and cognitive dispositions to respond Availability bias- probability assigned based on ease of recall of specific examples Confirmation bias - selectively accepting or ignoring data

Cognitive Dispositions to Respond Croskerry P, Acad Med, 2003, 78:775-780 Fatigue Team factors Affective state Ambient conditions Past experience Patient factors

Skills Formulation of hypotheses How to pose questions Going from the particular to the general Are they testable? Revising with new data Identifying the key issues Formulation of hypotheses

Skills Symptoms link with physical findings? Lab data with symptoms and signs? Finding common mechanisms Formulation of hypotheses Making logical connections between ideas

Skills Formulation of hypotheses Making logical connections between ideas Utilization of data Sensitivity and specificity of tests Pre and post-test probabilities Red flags

Skills Formulation of hypotheses Cultural Gender Making logical connections between ideas Utilization of data Identify assumptions Cultural Gender Contextual, e.g., in our ED, upper lobe infiltrates are all TB

Attitudes Open mind - willingness to consider alternative explanations Awareness of one’s own cognitive processes - what type of reasoning was I using? (metacognition) Reflection - how did we go wrong? Where did we make a mistake?

Critical Thinking vs Clinical Reasoning

The Clinical Reasoning Paradigm What do “experts” (routine experts?) do? Content knowledge vs thought process Mental representations of disease processes Illness scripts (mini-patterns) Semantic qualifiers (e.g., acute vs chronic, proximal vs distal) Encapsulated knowledge (one type of knowledge embedded in other knowledge - basic mechs within clinical examples - example: “sepsis”)

How often do we need critical thinking in the clinical setting? Bowen J, NEJM, 2006:355;2217-2225 Pattern recognition (non-analytical thinking) is “essential to diagnostic expertise” “Deliberative analytic reasoning is primary strategy when a case is complex…”

Clinical Reasoning and Critical Thinking

Clinical Reasoning My bias… The 80/20 rule 80% of clinical medicine, pattern recognition works well. 20% of clinical medicine, to get it right, you need to apply the knowledge, skills, and attitudes of critical thinking. The key - knowing into which group your patient fits.

Can we teach critical thinking?

Critical Thinking in College, Council for Learning Assessment (CLA), courtesy of Richard Hersh, EdD, lecture at HMS, Jan. 19, 2007

Some Strategies for Teaching Critical Thinking Go back to the knowledge, skills, attributes Be explicit that we are teaching critical thinking Woven into teaching content Separate teaching modules Beware the hidden curriculum!! A few thoughts from the literature (and my experience).

Concept Maps Guerrero, Acad Med 2001;76:385 Torre et al Concept Maps Guerrero, Acad Med 2001;76:385 Torre et al., Am J Med 2006;119:903 Graphic devices to represent relationships between multiple concepts Reinforce mechanistic thinking Make links explicit

Higher Order Concepts Auclair F, BMC Medical Education 2007;7:16 32 third year students given complex CPC case (endocarditis) to analyze 12/32 made correct dx Diagnostic accuracy  use of higher order concepts. Students who missed dx reported factual observations 19/25 students: given problem formulation (i.e, concept links) made dx Problem not knowledge but moving from fact to concept

Case Conference Traditional 65 year old homeless man back pain Hep C, spinal lymphoma Later abn CXRMAC Discuss: tests, meds, each disease in isolation

Case Conference Traditional 65 year old homeless man back pain Hep C, spinal lymphoma Later abn CXRMAC Discuss: tests, meds, each disease in isolation Critical thinking 65 year old homeless man back pain Hep C, spinal lymphoma Unifying mechs? Abn CXRMAC Discuss: make links -immune problemHIV

Model the Process Think out loud Discourage quick jumps to the dx Force the student to assess her own thought process Give frequent feedback Test them on the process as well as the content

Final Thoughts… There is more to be done to understand the elements of critical thinking. If we are serious about this, we need to explicitly teach the process. Critical thinking and clinical reasoning (as presently defined) are not the same. Faculty development will be key.