Health Care Processes and Decision Making_Lecture 3_ slides

Editor's Notes

• #2: No audio. Recording preparation.
• #3: Welcome to The Culture of Health Care: Health Care Processes and Decision Making. This is Lecture c. The component, The Culture of Health Care, addresses job expectations in health care settings. It discusses how care is organized within a practice setting, privacy laws, and professional and ethical issues encountered in the workplace.
• #4: The Objectives for Health Care Processes and Decision Making are to: Describe the elements of the “classic paradigm” of the clinical process. List the types of information used by clinicians when they care for patients. Describe the steps required to manage information during the patient-clinician interaction. List the different information structures or formats used to organize clinical information. Describe different paradigms and elements of clinical decision making. Explain the differences among observations, findings, syndromes, and diseases. Describe techniques or approaches used by clinicians to reach a diagnosis. List the major factors that clinicians consider when devising a management plan for a patient’s condition, in addition to the diagnosis and recommended treatment. Describe the role of EHRs and technology in the clinical decision-making process.
• #5: This lecture will discuss how clinicians arrive at a specific diagnosis to guide treatment. The previous lecture concluded with the problem list depicted on this slide, derived from an analysis of information gathered about a man with swelling in his ankles. On the right are the beginnings of the differential diagnosis. Consider first the weight gain and edema [ih-dee-muh], which the man reported in his history. Edema could be caused by several conditions of different organ systems. Edema may result from heart disease, for example, caused by long-standing high blood pressure. It may also result from liver disease, such as cirrhosis [si-roh-sis] due to chronic alcoholism. It could also be a case of kidney disease, such as nephrotic [nuh-frot-ik] syndrome. In some countries, edema such as this might be the result of severe malnutrition, although this form is rare in the United States. The slide also includes the differential diagnosis for shortness of breath, or dyspnea [disp-nee-uh]. This condition may result from diseases of many organ systems, such as heart disease, lung disease, anemia or low blood count, physical restriction due to a large abdomen in obese patients, or deconditioning due to inactivity. Some medical conditions or categories of conditions exist on both lists; for example, hypertension could cause both edema and dyspnea, and these may be clues to what’s wrong with this man. These data allow the clinician to guess about the condition in question, but this kind of reasoning goes only so far in reaching an accurate diagnosis. To think about the problem in a more structured way, some rules and procedures are needed.
• #6: This slide lists categories of techniques or processes that clinicians use to help them think about a diagnosis. These include systematic approaches that run through every organ system, such as the mnemonic [ni-mon-ik] “vindicate.” This memory aid helps students to remember diagnoses in a systematic fashion, in which V stands for vascular diseases, I for inflammatory diseases, N for neoplastic diseases, D for degenerative or deficiency diseases, I for idiopathic diseases and also for intoxications, C for congenital conditions, A for autoimmune or allergic diseases, T for traumatic events, and E for endocrine diseases. Another approach is the anatomic approach in which a clinician uses his or her knowledge of anatomy to think through the potential causes of the problem. For example, chest pain can result from a disorder in any number of structures, from the skin to the esophagus to the windpipe. Simply by thinking through this anatomy, a clinician can generate a fairly complete differential diagnosis of all the possible diseases that might cause chest pain. A third approach is pathophysiologic [path-oh-fiz-ee-uh-la-jik]. The clinician uses his or her knowledge of physiology to think through the potential causes of the problem. Another common approach is pattern recognition, which is used by clinicians who have sufficient experience with the condition to recognize that a particular case fits it or doesn’t fit it. Other mnemonics may have nothing to do with the content but are helpful in remembering useful groupings. The mnemonic “PT Barnum Loves Kids,” for example, reminds the clinician that the causes of cancer that spread to the bone include prostate, thyroid, breast, lung, and kidney. Clinicians also make use of heuristics [hyoo-ris-tiks], such as the old saying “When you hear hoof beats, look for horses, not zebras,” which is a reminder to always think of the simplest explanation first. Clinicians sometimes make informal use of techniques based on Bayes’ [bayz] theorem, which can calculate the probability of a condition based on the findings that are present and the background probability of the condition. Finally, the temporal pattern of illness helps to explain the underlying pathophysiology [path-oh-fiz-ee-ol-uh-jee]. For example, the same symptoms occurring suddenly are likely to be caused by a different process than symptoms that evolve over months.
• #7: Here are two examples of systematic approaches to facilitate brainstorming and help expand the differential diagnosis. On the left is the mnemonic “vindicate,” which helps clinicians remember vascular, infectious, neoplastic, drug-induced, and other causes of disease. In each category are many subcategories; for example, infectious diseases include viral, bacterial, parasitic, and fungal diseases. These groupings take advantage of fundamental properties of human memory, enabling us to remember more individual items when they are grouped than we could remember in a simple list. On the right is another systematic approach based not on the process but on the organ system involved, such as neurologic diseases, cardiovascular diseases, and pulmonary diseases. Clinicians may use either or both of these approaches to help them think through a case when a comprehensive approach is needed.
• #8: This slide illustrates how a differential diagnosis may be generated by recalling the underlying physiology. In this case, when evaluating a patient with jaundice, a clinician may recall all the steps in the formation and excretion of bilirubin [bil-uh-roo-bin], from hemoglobin [hee-muh-gloh-bin] in the red blood cells to the excretion of urobilinogen [yer-uh-buh-lihn-uh-jin]. By remembering all of the steps involved in the physiology, a clinician can construct a fairly complete differential diagnosis for this problem. More often, rather than a highly detailed differential diagnosis, clinicians think in terms of the major groups: disorders of red blood cells, disorders of the liver, and disorders of the gallbladder and biliary [bil-yuh-ree] system. By thinking first in terms of these large groups, the clinician may then pursue further information to simplify the problem by eliminating entire categories of disease.
• #9: Especially in neurologic diagnoses, clinicians may use the topographic pattern, the temporal pattern, and the clinical context. The topographic pattern refers to mapping symptoms to the specific location in the brain or nervous system responsible for that function. For example, the patient’s neurologic symptoms and signs on physical examination can be correlated with the exact location in the nervous system that might be responsible for these symptoms. The same is true for diseases of the nervous system that occur outside of the brain, such as in the spinal cord. In analyzing the temporal pattern, a clinician looks at the pace that symptoms appear or resolve to understand the underlying pathophysiological [path-oh-fiz-ee-uh-loj-ik-uhl] process that might be causing the problem. Given exactly the same set of symptoms—for example, numbness and weakness in the right arm and right side of the face—the clinician can infer what kind of process might be involved by considering the pace at which these symptoms appear. Seizures are essentially an electrical process and take place over a matter of minutes. So when a patient reports symptoms that appear and then disappear within minutes, it may well have been a seizure. Vascular events include stroke, transient ischemic [ih-skee-mik] attack, and migraine, and these events generally take place over minutes to hours. Therefore, if a patient presents with the same symptoms but they appear over many minutes or last several hours, they may be due to a vascular process. If these symptoms go away entirely, it may be a transient ischemic attack. If some symptoms persist indefinitely with permanent damage, then it’s a stroke. When symptoms appear over many hours to days or even weeks, this suggests an infectious cause. A brain abscess [ab-sess], for example, might cause the same symptoms of numbness, tingling, and weakness, but it evolves over several hours or days. If these same symptoms were to appear gradually over many months, in a pattern of more or less relentless progression, then they may be due to a neoplasm or cancerous growth. Neurodegenerative diseases occur slowly over many months or years. An example of such a disease that would cause the same set of neurologic symptoms would be amyotrophic [uh-my-oh-troh-fik] lateral sclerosis [skli-roh-sis]. Finally, some conditions are characterized by waxing and waning symptoms, superimposed on an underlying yet slowly progressive worsening of symptoms; this suggests a disease such as multiple sclerosis. In short, the neurologic diagnosis depends on combining the topography of the condition, indicating which part of the brain is involved, with the temporal pattern, which suggests what kind of process may be causing the trouble. Finally, the clinical context helps clinicians understand what non-neurologic process might be causing the condition. For example, a patient who has a fever is more likely to have an infection, whereas a patient with a comorbid [ko-mor-bihd] illness, such as valvular [val-vyuh-ler] heart disease, is more likely to have a heart condition as the cause, and a patient who smokes cigarettes is more likely to have cancer as the cause.
• #10: As mentioned earlier, another approach that clinicians use for more efficient diagnostic reasoning is to employ heuristics, or rules of thumb. This slide considers three examples of heuristics. The first is, “Err on the side of life,” which suggests emphasizing those conditions that are most life threatening or most conducive to treatment. The second expression is, “When you hear hoof beats, look for horses, not zebras,” which advocates thinking about the common diseases first because they are much more likely to occur. The third heuristic is, “You are more likely to see an uncommon case of a common disease than an uncommon disease,” which means that even if it seems like a rare condition, in terms of probability, it’s more likely to be a common one. There are drawbacks to using heuristics because they can lead to cognitive errors and biases; however, they provide a fast and frugal reference point, facilitating an appropriate working diagnosis with a minimum of resources, including time and attention.
• #11: Although not widely used in day-to-day clinical work, mathematical approaches to assist with diagnosis are employed informally in the clinic and formally in decision-support systems and guidelines. Bayes’ theorem has been widely used to help determine the probability of a condition given its prevalence in the population and the findings in a given patient. The mnemonics SpIN and SnOUT are reminders that the specificity of a test indicates how useful it is for ruling a condition in, and the sensitivity of the test indicates how useful it is for ruling a condition out. Mathematical approaches are also used to derive decision rules for determining the likelihood of conditions. An example is the use of Wells criteria for determining the likelihood of a pulmonary embolus [em-buh-luhs], or blood clot. Many clinicians use pocket calculators or online calculators to determine the Wells score to help them decide whether to do further testing for pulmonary embolus. Simple scoring rules (Centor [sen-tor] criteria) also help determine the probability of streptococcal [strep-tuh-kok-uh l] pharyngitis [far-in-jahy-tis], which can lead to more appropriate antibiotic prescribing. Finally, formal decision analysis is applied to clinical problems in order to set policy and create guidelines. These techniques are especially amenable to providing decision support with computer systems because calculations that may be difficult to do in one's head are trivial for a computer if the correct data is available.
• #12: Information systems and technology are tools that facilitate the clinician’s ability to collect and analyze patient data. As discussed earlier, data collection is a cyclical or iterative process, and data may come from many sources, including other providers, the patient’s personal health record, and even a patient’s mobile application. Electronic health records and clinical information systems facilitate both the data collection process and display of the data to support clinicians with data analysis so they can quickly arrive at the most appropriate patient diagnosis based on available information. Clinical decision support systems are designed to facilitate the decision-making process at the point of care by providing access to additional information and medical knowledge. For example, these systems may provide access to a “library,” or a robust resource of signs and symptoms information with commonly associated diseases and diagnoses. Some also may provide associated treatments and plan of care activities. The goal of decision support systems is to facilitate the clinician’s efforts in diagnosing patients, but they don’t replace the experienced clinician who makes a final determination based on his or her direct patient interaction and working knowledge. Electronic systems and technology are tools that facilitate and support the clinician’s decision-making process. While they don’t replace any of the techniques for diagnostic thinking presented in this unit, the overall benefits of using these information systems include improved patient care outcomes and care quality as well as improved patient safety.
• #13: This concludes Lecture c of Health Care Processes and Decision Making. In summary, this lecture examined diagnostic thinking and looked at techniques for making a diagnosis, such as using a systematic or a pathophysiologic approach. Also discussed were topographic, temporal, and clinically contextual patterns of data for use in diagnosis; the use of heuristics; and mathematical approaches to assist in clinical decision making.
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