chapter 3: finding relevant evidence to answer clinical questions
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Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Chapter 3: Finding Relevant Evidence to Answer Clinical
Questions
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answering Clinical Questions
Finding the right information to answer a given question often depends on the source of the information
Searching for evidence that has already been appraised for the quality of the study methodology and the reliability of its findings is desirable
Pre-appraised literature
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Tools for Answering Clinical Questions
Begin with a PICOT question Determine the source from which the best evidence is
available Clinicians need peer-reviewed research
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External Sources of Evidence
Textbooks and journals Consolidated resources
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Hierarchy of Evidence
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Question
Which of the following sources of evidence is best able to inform a nurse’s clinical practice?
a. A well-designed randomized controlled trial (RCT)
b. A systematic review that encompasses multiple studies
c. Expert opinion of experienced and educated nurses
d. A case study that addresses an unique clinical scenario
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Answer
b. A systematic review that encompasses multiple studies Rationale: Systematic reviews are considered to be
higher on the hierarchy of evidence than expert opinion or individual RCTs and case studies.
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Which Resource or Database is a Good Match?
Online databases Grey literature Bibliographic versus full-text databases
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Collaboration with Healthcare Librarians
Librarians are a rich source of assistance They are especially valuable when time is of the essence
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Keyword and Controlled Vocabulary Searching
Keyword searching is searching using simple, everyday language
Controlled vocabulary systems, e.g., MeSH Normally have a hierarchical structure that helps the
searcher retrieve the more specific terms that fall under a general term
Most large bibliographic databases (MEDLINE, CINAHL, and PsycINFO) use a controlled vocabulary to describe the content of references
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
Tell whether the following statement is true or false. A controlled-vocabulary system may yield fewer hits than
a keyword search, but these hits are more likely to be relevant to the clinical question.
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Answer
True Controlled vocabulary systems exist to increase the
relevance of search results while limiting the number of less-relevant hits.
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Combining and Limiting Searches
Combining search terms from within a PICOT question focuses the search results
Consider that different search engines process terms in the search box in different ways
Using the “limit” function is designed to help the searcher pare down the large results list
Manage inclusion and exclusion criteria carefully
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Online Searches
Managing citations Saving searches Organizing searches
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Selecting Databases: Cochrane Databases
A collection of 6 different databases “Gold standard” database is the Cochrane Database of
Systematic Reviews (CDSR) Systematic reviews are based on critical appraisal
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Selecting Databases: National Guideline Clearinghouse
A comprehensive database of evidence-based clinical practice guidelines
Guidelines are systematically developed statements about a plan of care for a specific set of clinical circumstances involving a particular population
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Selecting Databases
MEDLINE - covers medicine, health, and the biomedical sciences
CINAHL – covers 13 nursing and allied health disciplines EMBASE - major European biomedical and pharmaceutical
database PsycInfo – covers psychology, behavioral sciences, and
mental health
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Question
Which of the following online evidence sources is most likely to provide pre-appraised evidence?
a. CINAHL
b. MEDLINE
c. PubMed
d. Cochrane Library
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Answer
d. Cochrane Library Rationale: The Cochrane Databases consist of systematic
reviews that synthesize evidence from multiple peer-reviewed sources. CINAHL, MEDLINE, and PubMed may contain evidence at a synthesis level, but are more often sources of individual articles that a nurse must appraise.
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Specialized Search Functions
PubMed Ovid EBSCO
Any search for evidence must be followed by critical appraisal
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