Searching Medline

Helen Rowlandson

Principal Medicines Information PharmacistLondon Medicines Information

(Northwick Park) London

July 2008 course - participants responses

17 questionnaires returned More than half have had formal training (during

pre-reg, at university, during diploma/certificate, or by NHS library service)

Nearly all have had informal training in-house in MI service

Most participants have used Dialog and a few use Ovid or Pubmed

Only a few have starting using NLH regularly

Main issues/problems Searches produce too many hits - how do you

narrow/limit your search down?

Searches produce irrelevant hits – how to you find relevant hits for your topic?

Difficulty finding good quality full text articles

Finding/deciding which are the relevant search terms to use –use of the MeSH browser/ MESH descriptors/MESH headings/thesaurus

Use of explode function

National Library of Health (NLH) Interface Issues

Slow and crashes all the time Thesaurus unavailable at times Map to Thesaurus button is not

automatically ticked More hits with Dialog

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

Searching basics – a refresher

Large databases – electronic searching is essential

A controlled vocabulary or a thesaurus is necessary

A means of combining terms is also required e.g. BOOLEAN operators

A AND BA B

A OR BA B

A NOT B A B

Boolean operators

What is Medline?

Vast source of medical information Medicine, Dentistry, Veterinary, Psychology

Covers Clinical medicine, anatomy, pharmacology,

toxicology, genetics, microbiology, pathology, environmental health, occupational medicine, psychology, biomedical technology

5,000 journals indexed, 70 countries

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

Focus (Major)Only includes articles where the MeSH

heading (descriptor) is the main focus of the article

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 (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

Check Tags All relevant tags are attached to the article These are essentially used as “limit” functions

Human Child Adult Aged Male Female etc..

Type in “female” and look at annotation

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 (ie 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

Log in using athens username and password”

Healthcare databases advanced search

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 recent papers about SSRIs or SNRIs being used in the treatment of Huntington disease?

Worked example 2

Are there any recent RCTs of the UK-available acetylcholinesterase inhibitors (galantamine, rivastigmine, donepezil) in Lewy Body Dementia?

Worked example 3

Are there any articles which discuss using high dose vitamin supplementation to treat autism?

NB – remember that your enquirer’s way of describing what he is asking for may not necessarily be exactly how MeSH describes it….

ANY QUESTIONS?