Tips for Teachers of Evidence-based Medicine: Making Sense of Decision Analysis Using a Decision Tree

Decision analysis is a tool that clinicians can use to choose an option that maximizes the overall net benefit to a patient. It is an explicit, quantitative, and systematic approach to decision making under conditions of uncertainty. In this article, we present two teaching tips aimed at helping clinical learners understand the use and relevance of decision analysis. The first tip demonstrates the structure of a decision tree. With this tree, a clinician may identify the optimal choice among complicated options by calculating probabilities of events and incorporating patient valuations of possible outcomes. The second tip demonstrates how to address uncertainty regarding the estimates used in a decision tree. We field tested the tips twice with interns and senior residents. Teacher preparatory time was approximately 90 minutes. The field test utilized a board and a calculator. Two handouts were prepared. Learners identified the importance of incorporating values into the decision-making process as well as the role of uncertainty. The educational objectives appeared to be reached. These teaching tips introduce clinical learners to decision analysis in a fashion aimed to illustrate principles of clinical reasoning and how patient values can be actively incorporated into complex decision making

Severe Acute Respiratory Syndrome–associated Coronavirus Infection

Whether severe acute respiratory syndrome–associated coronavirus (SARS-CoV) infection can be asymptomatic is unclear. We examined the seroprevalence of SARS-CoV among 674 healthcare workers from a hospital in which a SARS outbreak had occurred. A total of 353 (52%) experienced mild self-limiting illnesses, and 321 (48%) were asymptomatic throughout the course of these observations. None of these healthcare workers had antibody to SARS CoV, indicating that subclinical or mild infection attributable to SARS CoV in adults is rare

Human Metapneumovirus Detection in Patients with Severe Acute Respiratory Syndrome

We used a combination approach of conventional virus isolation and molecular techniques to detect human metapneumovirus (HMPV) in patients with severe acute respiratory syndrome (SARS). Of the 48 study patients, 25 (52.1%) were infected with HMPV; 6 of these 25 patients were also infected with coronavirus, and another 5 patients (10.4%) were infected with coronavirus alone. Using this combination approach, we found that human laryngeal carcinoma (HEp-2) cells were superior to rhesus monkey kidney (LLC-MK2) cells commonly used in previous studies for isolation of HMPV. These widely available HEp-2 cells should be included in conjunction with a molecular method for cell culture followup to detect HMPV, particularly in patients with SARS

Focus Topic:Decision-Making Regarding Resuscitation from Cardiac Arrest in the ICU

Cardiopulmonary resuscitation (CPR) in intensive care units (ICUs) differs in several ways from treatment of a cardiac arrest occurring outside the hospital or in other areas of the hospital, not only in the availability of advanced invasive treatment options (such as extracorporeal life support) but also in pre-existing conditions and severity of illness which may make prognostication more difficult. In addition, patients in the ICU are often receiving substantial levels of life-supporting therapies when arrest occurs, and thus CPR may have minimal prospects of success. Application of the ethical principles beneficence, maleficence, autonomy, and (distributive) justice as well as careful consideration of the treatment pillars “medical indication” and “patient’s consent” is therefore a special challenge, especially in relation to withholding or terminating resuscitative attempts. Following these principles, this chapter spotlights the topics “slow codes,” “do not attempt resuscitation” orders, and the special challenges of extracorporeal CPR.</p

Focus Topic:Decision-Making Regarding Resuscitation from Cardiac Arrest in the ICU

Cardiopulmonary resuscitation (CPR) in intensive care units (ICUs) differs in several ways from treatment of a cardiac arrest occurring outside the hospital or in other areas of the hospital, not only in the availability of advanced invasive treatment options (such as extracorporeal life support) but also in pre-existing conditions and severity of illness which may make prognostication more difficult. In addition, patients in the ICU are often receiving substantial levels of life-supporting therapies when arrest occurs, and thus CPR may have minimal prospects of success. Application of the ethical principles beneficence, maleficence, autonomy, and (distributive) justice as well as careful consideration of the treatment pillars “medical indication” and “patient’s consent” is therefore a special challenge, especially in relation to withholding or terminating resuscitative attempts. Following these principles, this chapter spotlights the topics “slow codes,” “do not attempt resuscitation” orders, and the special challenges of extracorporeal CPR.</p