Douglas J. Federman, MDDivision of General Internal Medicine

University of Toledo, College of Medicine

Goals• Identify sources of medical

information• List resources that are appropriate for

the task • List strategies to improve the

sensitivity and specificity of searches

Personal• entertainment• purchasing

– compare prices– find unusual items

• search for information about yourself– as a physician– as a professor– as a residency program

NEJM January 7, 2010

Evidence-based Medicine (EBM)1. Ask an answerable question2. Search the literature3. Assess the validity4. Apply the results5. Assess your own skills

Answerable Questions: PICO1.Person2.Intervention3.Comparison4.Outcome

ExampleWill a PSA measurement benefit my patients?

In asymptomatic, white men does the measurement of a PSA increase life expectancy when compared to watchful waiting?

EBM Failures – 8 ThemesSkills in

searchingAccess to

information (likely improved since publication)

Clinical question tracking

Time

Clinical question priority

Personal initiativeTeam dynamicsInstitutional

culture

Academic Medicine 2005; 80(2)

Choose the Right Tool for the Job:In the Office

• 56% of searches were performed on Google, 9% Pubmed, 4% Google Scholar, 3.5% Yahoo [NEJM 354(1)]

• NEJM Case studies, students found results 58% with Google [BMJ 333(7579)]

Choose the Right Tool for the Job:In the Office

• Brief, time constrained• Quick, single answer searches• Online textbooks, AFP, Stat!Ref, MD-Consult,

UptoDate, DynaMed, eMedicine, POEMS, Cochrane database

• Many require a subscription, but your hospital or university often has a subscription

• Internet search engines are quick, and the answer is frequently in the top 10 items

Research• Goal – comprehensive search• Combine sources such as PubMed, Embase,

Cochrane database, citation search• Use multiple modalities

• computer, bibliography, communication with authors and experts, clinicaltrials.gov

• Use a librarian!• Example – meta-analyses

Google• Google search• Probabilistic – sites can pay for

high ranking, clients can cheat• Google scholar• Alternatives – Bing, Ask, AltaVista,

Yahoo, Dogpile…

Google- TipsLearn the advanced interface, if availableShortcuts:

Order matters, use the most important one first

‘+’ to force a term in‘-’ to exclude a term“quoted phrases”[2004 2005] is not equal to [2004 OR

2005] or [2004..2005]Wildcard [Obama voted * on the * bill][site:www.utoledo.edu] or [site:.gov]

Google help pages or GoogleGuide.com

Internet Search EnginesAdvantages Disadvantages

QuickNo special termsHigh # of hitsUsually effective

Non-specific resultsSifting good/bad

resultsHigh # of hitsNot limited to journals

(scholar is better for this)

Medline: The journal subset of PubMed/NLM

• 1950-Present• ~5280 journals• >19,000,000 articles• Organized by MeSH

Use their tutorial!

Medline - Reference Structure• MeSH• Mapping of text to MeSH• Free text as effective as MeSH

search for most users. • Other databases that lease the

data may give better yields

Medline• Search from the hospital or campus

to maximize full-text retrieval• For non-critical searches (an article,

not all articles) consider MDConsult, Google Scholar, or follow a reference from UpToDate which will lead to a full text article on the first try

Medline - Title SearchAdd [ti] to your search termLooks in title or abstract for that exact

termWill not look for matching MeSH terms or

synonymsCombine terms using OR (AND is assumed)

e.g. (cardiac[ti] OR heart[ti] OR coronary[ti])

Note the parentheses are important here

Medline - Author SearchSearch as they are listed in citations:Lastname F[au]Lastname FM[au]

Use the Single Citation Matcher

What to do when your search fails?• Too few articles – broadening

• Use “OR” with synonyms and word variations

• Look for “Related Articles”• Look at the MeSH terms from the

relevant articles• Ugh! – search the MeSH database from

the Advanced Search page

What to do when your search fails?Too many articles – narrowing

Add more terms (always start simple) Use Limits/FiltersCore Clinical Journals or Abridged Index

MedicusLook for more specific terms in the

MeSH of relevant articles

Quick links to quickly practice EBM

Pubmed FeaturesFull text links for many articlesSave searches to repeat in the futureExport citations to email or a text file which

can be imported into a citation manager directly

Many other databases for researchersGenomes (sequences, domains, maps…)ProteinsChemicals

SummaryPractice practicing EBM

Ask questions that will focus your literature search using the for components Person Intervention Comparison Outcome

Search the literature using the tool you are most comfortable with. There is little evidence for a specific tool unless you are performing a comprehensive search for research.

SummarySelecting tools with full text resources will

improve speed of your tasksTake home: 2 sites for help

www.googleguide.comwww.ncbi.nlm.nih.gov/pubmed