How to find evidence when you need it, part 1: Databases, search programs, and strategies

Does the addition of a glycoprotein Ilb/IIIa receptor antagonist to heparin and P blockade decrease mortality in emergency department patients with chest pain and nondiagnostic ECGs? Does a negative troponin 1 at 6 hours after onset of chest pain rule out myocardial infarction? When should I suspect myocardial infarction in patients presenting to the ED who have previously received heart transplants? Is "zero tolerance" for missed myocardial infarction a cost-effective policy for an urban ED? Are clinically stable patients with cocaine-related chest pain at risk for near term life-threatening events? These questions are only a few among those potentially relevant to the evaluation and management of patients presenting to EDs with possible myocardial ischemia. They are formulated with varying degrees of specificity and pertain to different aspects of clinical decisionmaking for such patients. A similar set of questions could be generated in relationship to almost every patient that we encounter. Physicians have a professional obligation to base their clinical decisions on the best evidence available.(1)This assumption is the cornerstone of the concept of evidence-based medicine. Given the density and variety of questions that emergency physicians routinely face in the course of everyday practice, as well as the time constraints characteristic of emergency care, the challenge posed by the cited assertion calls for considerable resources and skills to address. In this and in future installments of this skills series, we will introduce the reader to some of the resources most useful to an emergency practitioner and to the essential skills required to use them. In this article, we will focus on the knowledge required to match questions to appropriate databases and approaches to searching. This requires knowledge of databases, search engines, and strategies and of how these components can be used to locate the best and most relevant evidence. (2-4)