Searching Medline

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Searching Medline. Alex Denby Regional MI Manager London Medicines Information Service (Northwick Park Hospital). Main issues/problems. General Searches produce irrelevant hits – how to you find relevant hits for your topic? Difficulty finding good quality full text articles - PowerPoint PPT Presentation

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Searching Medline

Alex DenbyRegional MI ManagerLondon Medicines Information Service(Northwick Park Hospital)

Main issues/problemsGeneral Searches produce irrelevant hits – how to you

find relevant hits for your topic? Difficulty finding good quality full text articles Not using to full potential

Searching techniques Finding/deciding which are the relevant search

terms to use –use of the MeSH /EMTREE terms MeSH terms not updated very often – drug

names CAS no searches vs. free text Free text searching which field to use Different thesaurus for the 2 databases Narrowing down searches

NLH Software Problems

Slow and crashes all the time Doesn’t reliably save articles No results displayed even though hits

found Takes a long time to do searches

Plan

Searching basics – a refresher (precourse material)

What is Medline? (precourse material) Medical Subject Headings (MeSH) NLM’s MeSH browser Searching tools NLH software – the basics Worked examples

Searching Medline

Use indexing system - MeSH thesaurusControlled vocabulary with ~24,000

descriptorsEach represents a single conceptTree structure - hierarchalConstantly changing600+ added per year

Medical Subject Headings

Articles indexed by 3 tier systemMeSH descriptor (MeSH heading)MeSH qualifier (MeSH subheading) Items mentioned (check tags)Articles are indexed & then double

checked by another indexer must agree

MeSH Browser Open the Internet and type:

http://www.nlm.nih.gov/mesh/MBrowser.html

Right click & then click on “create a shortcut”

Now click on “Navigate from tree top”

MeSH Examples

Kidney Failure Depression Chronic Fatigue Syndrome PTSD Fluoxetine

Searching Tools Explode

Includes everything below in the tree structure Major descriptor (focus)

Only includes articles where the MeSH heading (descriptor) is the main focus of the article

Select Searches for the term without using Explode or

Major but includes all subheadings.

Quick questions…

What is the correct MeSH term to use for angina?

And if you exploded this term, what term(s) would you be also including in your search?

Subheadings (qualifiers)

Subheadings (allowable qualifiers) refine your search What aspect of the main heading is the author writing

about or discussing? Look at the definitions of the subheading e.g.:

Administration and Dosage Adverse Effects Analysis Chemistry Diagnostic use Economics History

e.g. AE: adverse effects

DU: diagnostic use

PK: pharmacokinetics

TU: therapeutic use

Check Tags All relevant tags are attached to the

article These are essentially used as “limit”

functions Human Child Adult Aged Male Female etc..

Check tags

Limits – publication types

If you want to search for papers that are meta analyses use the publication type limit function. Articles will then be meta-analyses

If you use the MeSH heading ‘meta-analysis as a topic’ from tree E the articles you will get will be about meta-analysis as a study design(methods etc..)

Look at the MESH browser for definitions

Supplementary Concepts

Searches for substances that are not defined in MeSH (i.e. don’t have MeSH terms)

Supplementary chemical record >30,000 substances undergoing clinical

development – but not all will become commercially available medicines

Depending on software - search by CAS registry number or free text

Quick question…

What is directly above olanzapine in the MeSH tree?

What is its CAS registry number?

Medline & MeSH Recap

Successful searching is finding correct indexing term

MeSH headings Scope Notes Focus/Explode Subheadings/Check Tags Supplementary concepts

Accessing Medline?

MEDLINEOVID

MEDSCAPE

SILVER PLATTER

PUBMED

NLH

National Library for Health software

Open Internet and type:http://www.library.nhs.uk/Default.aspx Click “Login now” (LHS of screen) Right click & then click on “create a

shortcut” Enter Athens password Click on “Healthcare Database Advanced

Search” and select Medline.

NLH software

Search one database at a time Medline 1950 to date 2 options to search for terms:

Thesaurus mappingBrowse headings

NLH software

Major /Explode Tree structure Subheadings Supplementary Concepts Limits Show titles

Worked example 1

Are there any papers specifically about the use of linezolid for the treatment of MRSA?

(Workshop question 1)

Worked example 2

Are there any review articles about inhaler use in asthmatic children under 4?

(Workshop question 2)

Worked example 3

Is there any evidence that minocycline is more effective than any of the other tetracyclines that are licensed for the treatment of acne (tetracycline, lymecycline, oxytetracycline, doxycycline)?

(Workshop question 5)

ANY QUESTIONS?

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