chapter 3: finding relevant evidence to answer clinical questions

Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 3: Finding Relevant Evidence to Answer Clinical

Questions


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


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


External Sources of Evidence

Textbooks and journals Consolidated resources


Hierarchy of Evidence


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


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.


Which Resource or Database is a Good Match?

Online databases Grey literature Bibliographic versus full-text databases


Collaboration with Healthcare Librarians

Librarians are a rich source of assistance They are especially valuable when time is of the essence


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


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.


Answer

True Controlled vocabulary systems exist to increase the

relevance of search results while limiting the number of less-relevant hits.


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


Online Searches

Managing citations Saving searches Organizing searches


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


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


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


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


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.


Specialized Search Functions

PubMed Ovid EBSCO

Any search for evidence must be followed by critical appraisal

chapter 3: finding relevant evidence to answer clinical questions

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