University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2014-07-18 Acute Stroke Decision-Making in Historical and Philosophical Context, 1960-2014 Shamy, Michel Christopher Frank Shamy, M. C. (2014). Acute Stroke Decision-Making in Historical and Philosophical Context, 1960-2014 (Unpublished master's thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/24697 http://hdl.handle.net/11023/1648 master thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Acute Stroke Decision-Making in Historical and Philosophical Context, 1960-2014 by Michel Christopher Frank Shamy A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS DEPARTMENT OF HISTORY PROGRAM IN THE HISTORY AND PHILOSOPHY OF SCIENCE CALGARY, ALBERTA JULY, 2014 © Michel Christopher Frank Shamy 2014 ii Abstract This thesis applies approaches from the history and philosophy of science to explore the decision- making of contemporary physicians in a common clinical scenario: the treatment of patients with acute stroke. Acute stroke decision-making during the period 1960 to 2014 therefore serves as a case study to address broader questions about how doctors make decisions. I argue that acute stroke decision-making is dependent upon a historically-determined concept of the acute stroke, in that the contemporary meaning of the disease “acute stroke” was established in response to the efficacy of the drug tissue plasminogen activator (tPA) as its treatment. Moreover, I propose that treatment decisions about the use of tPA for acute stroke involve simultaneous and inter-related processes of epistemic and ethical evaluation. Acute stroke decision- making can therefore be conceived as a medical, epistemic and ethical process, occurring within a historical context. This interpretation of acute stroke decision-making argues for the necessary role of the humanities — and especially of the history and philosophy of science — in the study of modern medical practice. iii Acknowledgements The path that has led to this thesis began in New Haven, and wound its way through Kingston, Toronto, San Francisco, Calgary and Ottawa. First, I would like to thank my undergraduate professors — among them Ted Bromund, Robin Winks, Joanne Freeman, and George Fayen — for teaching me to think and to write. I was inspired to apply a historical and philosophical approach to studying medicine through the writings and teachings of Drs. Jacalyn Duffin of Queen’s University and Ross Upshur of the University of Toronto. I must thank the many patients who, over the course of my clinical training, allowed me to participate in their care, and from whom I learned so much about stroke, about doctors, and about myself. I extend my thanks to Department of History at the University of Calgary for having accepted me into the Graduate Program in the History and Philosophy of Science (HPS). I would not have gotten to this point without the support and supervision of Professor Frank Stahnisch, whose mentorship has made me a better student, writer, scholar and doctor. I also would like to thank my committee — Professors Henderikus Stam, Megan Delehanty, Paul Chastko and Eric Smith — for their willingness to share in this process, and for their engagement to make this thesis as good as it can be. I have to thank Alberta Innovates – Health Solutions, without whose financial support it would not have been possible for me to complete this master’s degree. Funding from the Ottawa Hospital Research Institute, the Canadian Stroke Consortium and the American Academy of Neurology has also been much appreciated. I would also like to thank the Calgary Stroke Program — Drs. Andrew Demchuk, Michael Hill and Eric Smith especially — for their belief in my ability to make a meaningful contribution to clinical care through an HPS approach. I have to thank Drs. Phil Wells, David Grimes, Grant Stotts and Dar Dowlatshahi in the Department of Medicine at the University of Ottawa for their financial support, flexibility, and encouragement over the course of the last year. iv Finally, I have to thank my friends and family, for believing in me and caring for me all along this road. Mark Fedyk, I must thank you for being such a wonderful friend, mentor, and sounding board. Thank you, Mom and Dad, for all you have done over the last 33 years. Most importantly, your brilliance, dedication and kindness were, are, and always will be, an inspiration. And to Claire: 1000 thank yous to go along with the 1000 times I have fallen in love with you. This would not have been possible without you. v Dedication For my parents, with love vi Table of Contents Abstract ii Acknowledgements iii Dedication v Table of Contents vi List of Figures & Illustrations viii Glossary ix Epigraph xv Introduction 1 How Do Doctors Make Decisions? 1 Perspectives on Medical Decision-Making 5 Rationalistic Approaches to Decision-Making 12 Heuristic Approaches to Decision-Making 16 Social Psychological Approaches to Decision-Making 21 Approaches to Decision-Making from the History & Philosophy of Science 26 The Case of Acute Stroke Decision-Making 30 Outline 37 Chapter 1: The Meaning of “Acute Stroke” 40 Introduction 40 History, Epistemology & Ontology 41 A Brief Historiography of Stroke 51 Treatability & Time 56 Acuity & the Acute Stroke 60 Acute Stroke & the NINDS Trial 63 Preconditions of the Acute Stroke 72 Vascular Anatomy 74 Localizability of Pathology 77 Ischemia and Hemorrhage 78 CT Scans 81 Thrombolysis 85 Penumbra 88 Conclusions 92 Chapter 2: Epistemic Evaluation in Acute Stroke Decision-Making 96 Introduction 96 Propositions, Beliefs & Knowledge 98 Epistemic Evaluation & Evidence-Based Medicine 104 Acute Stroke & its Clinical Propositions 112 Epistemology, History & Treatability 118 Conclusions 129 vii Chapter 3: Ethical Evaluation in Acute Stroke Decision-Making 133 Introduction 133 Principlist Ethics & Everyday Medical Decisions 134 Causes, Consequences & Values in Acute Stroke Decision-Making 142 Evaluating Post-Stroke Outcomes 152 Evaluating Pre-Stroke States 158 Conclusions 164 Conclusions 169 Acute Stroke Decision-Making 169 Implications for Physician Decision-Making 175 Bibliography 181 Primary Sources 181 Secondary Sources 193 viii List of Figures & Illustrations Figure 1. CT Scan of the Brain depicting ischemic stroke 34 Figure 2. Digital Subtraction Angiogram of the Brain 35 Figure 3. “Acute Stroke” in MEDLINE 66 Figure 4. “Acute Stroke” in MEDLINE 67 Figure 5. CT Scan of the Brain depicting intracerebral hemorrhage 84 ix Glossary American Heart Association: American charitable organization that funds research into diseases of the heart and vascular system and that establishes national guidelines for the care of patients with these diseases; founded in 1924. Angiogram: An image that depicts blood vessels and the flow of blood through them. In relation to the brain, several techniques may be used. In digital subtraction angiography, catheters are advanced into the chest, neck or head, and radio-opaque dye is injected to depict the flow of blood through vessels in real- time. In CT angiography, radio-opaque dye is injected into the vein and the patient undergoes a CT scan, with an image produced depicting the presence of radio-opaque dye in the arteries or veins at a particular point in time. Aphasia: The inability to produce or comprehend language. A common symptom of stroke, most commonly associated with occlusions of the left middle cerebral artery. Apoplexy: A historical term derived from the Greek for being “struck down.” Over time, it has been used to refer to: any sudden loss of consciousness; the sudden onset of neurological symptoms; intracerebral hemorrhage. Artery: A vessel that carries blood away from the heart and towards the body’s tissues. x Cerebral Venous Sinus Thrombosis: A condition in which the veins of the brain or head may become blocked, potentially producing a back up of blood being drained from the head. May lead to hemorrhage into the brain. Central Nervous System (CNS): The brain and spinal cord. In contrast to the peripheral nervous system (PNS), which includes the nerves that run from the spinal cord to the muscles and skin. Computerized Tomography (CT): A technique to visualize the brain or other internal organs using x- ray based technology that resolves organs and tissues of shades of black or white. Epidural Hematoma: Bleeding into the space between the skull and the lining of the brain, most commonly produced by injury to the middle meningeal artery that runs through the skull just above the ear. May present as the sudden onset of neurological symptoms or loss of consciousness. Often fatal if not treated immediately. Heart and Stroke Foundation: Canadian charitable organization that funds research into heart and brain disorders, and advocates for patients at various levels of government. Hemiplegia: The inability to move one side of the body, such as the face, arm and leg. A common symptom of ischemic stroke or intracerebral hemorrhage. Hemorrhage: The release of blood into an organ or tissue, usually resulting from the rupture of an artery. xi Hypoxic-Ischemic Encephalopathy: A condition in which the whole brain is temporarily deprived of blood flow and oxygen delivery. Occurs in the setting of low blood flow due to blood loss, impaired heart function, or low blood pressure. Most often presents as loss of consciousness. Infarction: A general term that refers to the death of tissue from ischemia (impaired blood flow). Intracerebral: Within the brain. Intracerebral Hemorrhage: Bleeding into the substance of the brain, most commonly due to a small artery.