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Nursing: PICO + Evidence-Based Practice

A guide to online and print resources in nursing & nurse anesthesia.


Evidence-based Medicine is "the conscientious, explicit and judicious use of current best evidence in making decisions about the  care of the individual patient. It means integrating individual clinical expertise with the best available external clinical evidence from systematic research."
(From Dr. David Sackett's article. "Evidence-based Medicine: What it is and what it isn't" (BMJ 1996 Jan 13; vol. 312 (7023), pp.71-2).

PICO Worksheet

Databases for EBM Articles

Clinical Trial Registries

What is Evidence Based Medicine?

EBM Triad
Triad From: The Florida State University College of Medicine Charlotte Edwards Maguire Medical Library. Evidence Based Medicine Tutorial. "Definition of Evidence Based Medicine."  2011. Accessed 8-6-14.

Links for more information:

PICO: Frame Your Clinical Question

Frame the question:  write out your information need in the form of a question.  For example:

Does hand washing among healthcare workers reduce hospital acquired infections?

P = problem/patient/population       P = hospital acquired infection
I =  intervention                                 I = hand washing
C = comparison intervention          C = no hand washing; other solution; masks
O = outcome                                      O =reduced infection

Next, locate sources of evidence.  Begin with CINAHL w/Full Text and Medline.

Plan a search strategy
:  identify the major elements of your question.  Translate natural language terms to MeSH terms or subject descriptors.  TIPbegin your search with the P and I elements to keep your results broad.

natural language:
P (Problem/Patient/Population)= hosptial acquired infection
term mapped to database vocabulary:  cross infection  (Medline MeSH)   
cross infection  (CINAHL Heading)

I (
Intervention/Indicator) = hand washing
term mapped to database vocabulary: 
handwashing  (MeSH)
                                                                   handwashing  (CINAHL Heading)

A simple database search strategy should begin with the P and I, for example:

handwashing and cross infection   (using the MeSH or CINAHL terms)

View the results

You may want to narrow your search with terms for the Comparison, Outcome or type of study.Or you may want to view your results and full text articles to see what is reported there.

Tips for narrowing your search
1.  From the online thesaurus, choose a narrower, more specific term for your topic. For example, search the Medline thesaurus (MeSH) for infection, and notice the narrower term, catheter-related infections.

2.  Narrow with subheadings: restrict your results to a subtopic of interest. For example:  in Medline MeSH)  handwashing/standards

3.  Apply LIMITS: limit by age group if appropriate; limit by publication type--meta-analysis, practice guideline; language; date of publication; evidence based; systematic reviews; research or peer-reviewed (in CINAHL);

 Tips for expanding your search:
1. Add search terms (synonyms) that you find in the records of your initial search.
2. Truncation:  use the * at the end of the root of a term to search for plurals:  teen* retrieves teens, teenager, teenagers
3. In the MeSH thesaurus, or in CINAHL Headings, view the tree structure of terms and EXPLODE to retrieve the narrower terms.
4. View the list of references for additional relevant articles. 

Evidence Pyramid

Filtered Resources

These resources appraise the quality of studies, and sometimes make recommendations for practice.

Practice Guidelines

Grey Literature



Systematic Reviews
Address a focused clinical question where review authors systematically search for, identify, select, summarize and critically apraise all of the medical research literature available on a specific topic.  Statistical techniques may be used to combine the results of these studies.  The authors clearly state the search methods used to locate these studies.  It is important to examine the search methods used and decide for yourself if it was broad enough to include all of the relevant studies, and if the studies found were relevant to the clinical question.

Randomized Controlled Clinical Trial  (RCT)
An experimental design used for testing the effectiveness of a new medication or a new therapeutic procedure. Individuals are assigned randomly to a treatment group or a control group, and the outcomes are compared. RCT is the most accepted scientific method of determining the benefit of a drug or a therapeutic procedure. It represents the best evidence available, which is integrated into the final decision about the management of a condition by healthcare practitioners in what is called evidence-based healthcare.

Clinical Trial
an experiment performed on human beings in order to evaluate the comparative efficacy of two or more therapies. 

In the Cochrane Library database, the protocol outlines the question that the review authors are addressing, detailing the criteria against which studies will be assessed for inclusion in the review, and describing how the authors will manage the review process.

When results of individual studies are combined to produce an overall statistic.

Review Article
Brings together information about previously published research on a topic.  It provides a critical appraisal of the topic over a period of time. It is helpful in identifying the important literature on a topic. Given the vast amount of scientific literature published, review articles are an excellent tool for researchers wishing to research a topic.