Cover
Title Page
Contributors
Preface
CHAPTER 1: Clinical Reasoning
1. Introduction
2. What is clinical reasoning?
3. Why is clinical reasoning important?
4. History and examination
5. Probability and diagnostic tests
6. Clinicians are human too
7. Clinical reasoning matters to patients
8. Summary
9. Further reading/resources
CHAPTER 2: Evidence-Based History and Examination
1. Introduction
2. Evidence-based history
3. Natural history and context
4. Evidence-based physical examination
5. Using likelihood ratios
6. The limitations of evidence-based history and examination
7. Example: diagnosing stable coronary artery disease
8. Combining clinical findings
9. Conclusions
10. Further reading/resources
CHAPTER 3: Using and Interpreting Diagnostic Tests
1. Introduction
2. Normal values
3. Factors other than disease that influence test results
4. Operating characteristics
5. Sensitivity and specificity
6. Prevalence of disease in the population
7. Thresholds
8. Summary
9. Further reading/resources
CHAPTER 4: Models of Clinical Reasoning
1. Introduction
2. Deductive reasoning
3. Hypothetico-deductive reasoning
4. Inductive reasoning
5. Abductive reasoning
6. Rule-based/categorical/deterministic reasoning
7. Probabilistic reasoning
8. Causal reasoning
9. Making a diagnosis – hypothesis generation and modification
10. Type 1 and type 2 thinking – dual process theory
11. Errors in the diagnostic process
12. The reasoning of experts versus novices
13. Summary
14. Further reading/resources
CHAPTER 5: Cognitive Biases
1. Introduction
2. Case history
3. Common cognitive biases
4. Is bias only a type 1 thinking problem?
5. Cognitive biases and expert intuition
6. Summary
7. Further reading/resources
CHAPTER 6: Human Factors
1. Introduction
2. Error in healthcare
3. The limitations of human performance
4. Communication within teams
5. Embedding human factors in healthcare
6. Summary
7. Further reading/resources
CHAPTER 7: Metacognition and Cognitive Debiasing
1. Introduction
2. ‘Brutish automatism’
3. Cognitive debiasing
4. Overall challenges of debiasing
5. Summary
6. Further reading/resources
CHAPTER 8: Using Guidelines, Scores and Decision Aids
1. Introduction
2. Clinical guidelines
3. Scores and decision aids
4. The pitfalls of using guidelines, scores and decision aids
5. Applying clinical guidelines in practice – helping patients to share decision-making
6. Summary
7. Further reading/resources
CHAPTER 9: Teaching Clinical Reasoning
1. Introduction
2. A spiral curriculum
3. Educational theories relevant to clinical reasoning
4. Teaching techniques
5. Reflection in clinical reasoning
6. Summary
7. Further reading/resources
Recommended Books, Articles and Websites
1. Popular
2. For students and teachers
3. Academic
4. Articles
5. Websites (all accessed February 2016)
Index
End User License Agreement

List of Tables

Chapter 01
1. Table 1.1 Root causes of diagnostic error.
Chapter 02
1. Table 2.1 New York Heart Association Functional Classification of Heart Failure – assessment of the patient’s functional status in the history is crucial in guiding therapy and correlates with prognosis.
2. Table 2.3 Diagnosing coronary artery disease in patients with stable, intermittent chest pain.
Chapter 03
1. Table 3.1 Sensitivity and specificity. Sensitivity is the probability that the test will indicate disease in those with the disease, i.e. A/(A + C) × 100. Specificity is the probability that the test will be negative in those without the disease, i.e. D/(D + B) × 100.
Chapter 04
1. Table 4.1 Rule-based/categorical/deterministic reasoning.
2. Table 4.2 Type 1 and type 2 thinking – dual process theory.
3. Table 4.3 Some common cognitive errors in medicine.
Chapter 07
1. Table 7.1 Established strategies in medicine to mitigate cognitive and affective biases.
2. Table 7.2 Examples of biases that are common in certain situations.
Chapter 09
1. Table 9.1 Key topics in a clinical reasoning syllabus.
2. Table 9.2 ‘Chunking’ information into larger units – for example, precise medical terms, problem representation and illness scripts. A ‘chunk’ can vary in complexity from a semantic qualifier to a complex illness script.
3. Table 9.3 Applying theory to teach clinical reasoning.

List of Illustrations

Chapter 01
1. Figure 1.1 The elements involved in clinical reasoning, underpinned by a knowledge of basic and clinical sciences.
2. Figure 1.2 Clinical reasoning in multiple problem spaces: factors influencing clinical decision-making.
3. Figure 1.3 Number of diagnostic hypotheses during the steps in making a diagnosis.
Chapter 02
1. Figure 2.1 Configuration of the symptoms of a patient’s presentation.
2. Figure 2.2 Diagnosis of lobar pneumonia. Textbooks present 15 traditional physical findings of pneumonia (left), along with the assumption that each finding has similar diagnostic weight. The evidence-based method (right), based on study of actual patients, shows that five findings accurately increase probability of pneumonia, and only one finding decreases it.
3. Figure 2.3 Likelihood ratios: definition and examples. McGee’s Evidence Based Physical Diagnosis, 3rd Edition 2012.
4. Figure 2.4 Likelihood ratios: diagnostic weights. Clinicians should classify LRs into three groups: those with values greater than 1.0 increase probability; those with values less than 1.0 decrease probability; and those with values near 1.0 change probability very little or not at all.
5. Figure 2.5 Can evidence-based reasoning be used?
Chapter 03
1. Figure 3.1 Distribution of results in people with (A) and without (B) a disease.
2. Figure 3.2 A 70-year-old woman was admitted following a fall. She had hurt her left hip and was unable to weight bear. On examination, the left leg was externally rotated and extremely painful to move. Is there a fracture?
Chapter 04
1. Figure 4.1 A modified universal model of diagnostic reasoning. Although type 1 processes are intuitive, it does not mean that the decision-maker is unaware of them or that they cannot be changed. A clinician can pause to check his or her thinking and assumptions at any time. This ‘type 2 override’ (sometimes called ‘rational override’) is often triggered when something doesn’t fit, leading to thinking about things more analytically. In the same way, clinicians sometimes use ‘type 1 override’ (or ‘irrational override’ – although it is not always bad) – an example would be overriding a validated scoring system, for example the revised Geneva score for pulmonary embolism, which consistently outperforms clinical judgement, and despite a low score and negative D-dimer requesting a CT pulmonary angiogram anyway on the basis of ‘gut feeling’. Ix = investigations.
Chapter 05
1. Figure 5.1 Diagnostic momentum. ACS = acute coronary syndrome.
2. Figure 5.2 Different types of cognitive biases.
3. Figure 5.3 Dual process theory, or the ‘two-minds’ hypothesis.
4. Figure 5.4 The apparent effortlessness of expert intuition. For example, when you watch a great tennis player you might be forgiven for thinking you are watching effortless talent – what you cannot see is that they started playing tennis aged 4, practised for hours a day for many years, engaged in deliberate practice with the best coaches, and had the determination to learn from mistakes and improve. It is this that underpins the apparent ‘effortless’ performance, and what we observe in medicine as expert intuition.
Chapter 06
1. Figure 6.1 Everyday example of human factors engineering – a cash machine, or ATM. Cash machines around the world have the same design – from the arrangement of the numbers on the keypad to the fact that the machine beeps and flashes to remind you to take your card before it dispenses your cash. This is an example of human factors engineering, design that takes into account that ‘to err is human’. How many of us would walk off leaving our cards behind if cashpoint machines did not operate this way?
2. Figure 6.2 Swiss cheese model of accident causation. For example, blood transfusion has a series of defences, barriers and safeguards, from donation to screening to storage to administration. But in any human system, these defences can have holes in them – like Swiss cheese. If the conditions are wrong and these holes happen to align, a major adverse event can occur. The important thing to understand is that in order to prevent an adverse event from happening again, the latent conditions – or ‘root causes’ – must be addressed. Errors rarely happen because of the actions of one person.
3. Figure 6.3 Optical illusions. Do you see the vase or the faces?
4. Figure 6.4 Factors increasing the likelihood of diagnostic error.
5. Figure 6.5 A human factors training ‘hierarchy’. A human factors training programme in healthcare must include basic training for all staff, adapted to suit their roles. Specific team training (e.g. theatres, delivery suite, emergency department) is also important. Clinical leaders and managers need a greater awareness of system, process and equipment design. Some people can gain a master’s degree or even PhD in Ergonomics and Human Factors and become a project leader and mentor in an organisation.
Chapter 07
1. Figure 7.1 A schematic application of dual process model to diagnostic decision-making. The multi-channelled type 1 processes depict fast, intuitive decision-making, and the single-channelled type 2 process analytical decision-making. The executive override pathway shows type 2 surveillance and potential override of type 1 decision-making and provides the means for accomplishing metacognition and cognitive debiasing. The lower shaded box contains the mindware for debiasing.
2. Figure 7.2 Metacognitive schema for cognitive and affective debiasing.
3. Figure 7.3 Robust mindware is needed to deal with the wide variety of biases that enter into clinical decision-making.
Chapter 08
1. Figure 8.1 Examination of the ankle using the Ottawa Ankle Rule. The Ottawa Ankle Rule has a high sensitivity and moderate specificity, therefore a very low rate of false negatives. The original study reported that the Rule was 100% sensitive and reduced the number of ankle X-rays by 36% – subsequent larger trials replicated these findings. (Stiell IG, Greenberg GH, McKnight RD et al. A study to develop clinical decision rules for the use of radiography in acute ankle injuries. Ann Emerg Med 1992; 21:384–90.)
2. Figure 8.2 Evidence-based practice.
3. Figure 8.3 Values-based practice and the ‘two feet’ principle.
4. Figure 8.4 Portrayal of risks and benefits of treatment with antibiotics for otitis media designed with ‘Visual Rx’, a program that calculates numbers needed to treat from the pooled results of a meta-analysis and produces a graphical display of the result. From Edwards A, Elwyn G and Mulley A. Explaining risks: turning numerical data into meaningful pictures. BMJ 2002; 324:827–30.
Chapter 09
1. Figure 9.1 A spiral curriculum for clinical reasoning. In a spiral curriculum, topics are continually revisited with increasing levels of difficulty throughout one’s training and clinical practice.
2. Figure 9.2 Expert clinicians mainly use forward thinking and pattern recognition, which is more efficient than the hypothesis testing used by novices.
3. Figure 9.3 An example of forward thinking.
4. Figure 9.4 An example of a concept map (or tree) used in teaching, to facilitate organised learning and memory in what can appear to be a complex clinical topic.
5. Figure 9.5 The ‘Stop and Think’ framework.

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Preface

Excellence in medicine is not just about good knowledge, skills and behaviours. How doctors think, reason and make decisions is arguably their most critical skill. While medical schools and postgraduate training programmes teach and assess the knowledge and skills required to practise as a doctor, few offer comprehensive training in clinical reasoning or decision-making. This is important because studies suggest that diagnostic error is common and results in significant harm to patients. Diagnostic error typically has multiple causes, but two-thirds of the root causes involve human cognitive error – most commonly, when the available data are not synthesised correctly. While some of this is due to inadequate knowledge, a significant amount is due to inadequate reasoning.

Clinical reasoning has several elements, which are covered in this book, from evidence-based clinical skills to the use and interpretation of diagnostic tests to cognitive psychology, thinking about thinking and human factors. This book is designed to be an introduction for individuals and also a resource for a curriculum in clinical reasoning.

Clinical reasoning is not confined to doctors – we have written this book with advanced nurse practitioners and other clinicians in mind, and try to use the word clinician’ rather than ‘doctor’ whenever we can.

Clinical reasoning is relevant to every single specialty from general practice to surgery to the intensive care unit. While some aspects of clinical reasoning are not new, advances in cognitive psychology and a better understanding of patient safety mean there are elements of clinical reasoning that many clinicians may be unfamiliar with. We can only provide an introduction to the different elements of clinical reasoning in this book, so each chapter has a list of further reading and resources. We have also provided a list of recommended books, articles and websites at the end of the book so readers can continue to explore clinical reasoning in more depth for themselves.

We really enjoyed writing and editing this book, we hope you enjoy reading and using it!

Nicola Cooper and John Frain

January 2016