Chapter 2. Decision Making: Use of Evidence-Based Medicine

Making thoughtful decisions about patient care is at the core of a physician’s responsibilities. Multiple factors feed into clinical decision making: a physician’s experience, the values and preferences of the patient and patient’s family, socioeconomic factors, resources available in the community, and the best evidence that exists at the time. Physicians may have an understandable tendency to be influenced by a past missed diagnosis or an emotional case or to ignore information that conflicts with preconceived theories. While recent emphasis is on the importance of peer-reviewed evidence, a management plan based solely on evidence from the literature may fail if not accepted by the family. Peer-reviewed evidence is therefore a necessary but insufficient basis for clinical decision making.

Satisfying the need for evidence typically comes in three forms: keeping up to date, building expertise in a specific field, or answering questions related to the care of specific patients. Patient-centered evidence, the focus of this chapter, demands a streamlined approach. For most clinicians, it is not practical to spend hours reading dozens of studies to answer every clinical question that arises. The clinician must prioritize the most important patient-centered questions. A reasonable approach is as follows, using the mnemonic PARCA1:

1. 1. Prioritize the most important patient-centered questions.

   2. Assemble the four elements of an answerable question (PICO, described shortly).

   3. Retrieve the evidence.

   4. Critically appraise the evidence.

   5. Apply the evidence to the particular patient.

The following vignette demonstrates the application of this process:

The parents of a 4-month-old are worried about their infant’s frequent emesis after feedings. They tried positioning her upright after feedings, but she has continued to vomit, and her weight gain has been inadequate. Would a trial of a thickened formula help?

The physician must first decide whether it is important enough to warrant the time and effort of a literature review. If the question pertains to the mechanism of action of medications or the pathophysiology or signs and symptoms of a disease (a background question), the answers are likely found in textbooks or review articles. If the question aims to ascertain which therapy is most effective or whether a diagnostic test is useful (a foreground question), the answer is likely found in systematic reviews or original journal articles.

For many foreground questions, clinical guidelines, predigested evidence, or advice from colleagues, including subspecialists, is sufficient. For such questions, the next steps are formulating a specific clinical question (step 2) and applying the answer to the particular patient (step 5). For other questions, proceeding through all the PARCA steps is warranted.

The preliminary question (Will thickened formula help?) must be converted into a more complete, answerable format. One method, from Sackett,2 is summarized by PICO:patient or problem, intervention, comparison, outcome. The time invested in framing clinical questions in such a ...