Searching Medline

1. Searching Medline Janet West Principal Pharmacist Medicines Information Southern General Hospital NHS Greater Glasgow & Clyde

2. July 2007 course - participants responses • 12 questionnaires returned • More than half have had formal training (during pre-reg, at university, during diploma/certificate, or by NHS library service) • Informal training in-house in MI service • Most participants use Dialog and a few use Pubmed in addition • Of the Dialog users most use Advanced search option

3. Main issues/problems • Difficulty with limiting searches to a manageable number of hits • Use of the “tree” structure • Use of thesaurus mapping • Exploding and focussing – when to use • Difficulty with finding MeSH headings • Subheadings – when are they appropriate to use • Finding relevant articles e.g. about an adverse reaction to a particular drug as opposed to general info on its therapeutic use

4. Session aims • To understand the concepts of a basic search strategy in Medline • To describe the MeSH thesaurus in detail so that you will be able to apply MeSH to use Medline efficiently • To carry out advanced Medline searches

5. Contents • Searching basics – a refresher • What is Medline? • Medical Subject Headings (MeSH) • NLM’s MeSH browser • Dialog software – the basics • Worked examples

6. 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

7. Boolean operators • A AND B A B • A OR B A B • A NOT B A B

8. 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 • National Library of Medicine (USA)

9. Background • ~5000 journals indexed • (20,000 world wide) • 600 British • 70 Countries SILVER PLATTER MEDLINE PUBMED OVID DIALOG NHS MEDSCAPE

10. Searching Medline • To use Medline effectively we must know how indexing works • Each article is assigned a number of MeSH terms • Articles indexed by 3 tier system • MeSH descriptor (MeSH heading) • MeSH qualifier (MeSH subheading) • Items mentioned (check tags) • Articles are indexed & then double checked by another indexer  must agree

11. Medical Subject Headings • Use MeSH thesaurus • Controlled vocabulary with ~23,000 descriptors • Each represents a single concept • Constantly changing • 600+ added per year • Up to ~ 20 MeSH per article (av. 10-12) • Tree structure • Hierarchal structure

12. MeSH • Open the Internet and type: http://www.nlm.nih.gov/mesh/meshhome.html • Click on “online searching of MeSH vocabulary” • Right click & then click on “create a shortcut” • Now click on “Navigate from tree top” NLM MeSH Browser

14. MeSH Examples • Kidney Failure • Depression • Chronic Fatigue Syndrome • PTSD • Fluoxetine NLM MeSH Browser

15. MeSH Headings • 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 NLM MeSH Browser

16. 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? NLM MeSH Browser

17. 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 NLM MeSH Browser

18. Check Tags • All relevant articles 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

19. 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 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

20. 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 and combine with text word search using OR (not necessary in Dialog)

21. Quick question… • What is directly above olanzapine in the MeSH tree? • What is its CAS registry number?

22. Medline & MeSH • Successful searching is finding correct indexing term • Avoid needle in hay stack searching

23. Dialog software • Open Internet and type: http://www.datastarweb.com/NHS/ • Click “Athens users click here” • Right click & then click on “create a shortcut” • Enter Athens password

24. Dialog software • NHS England – access via Athens password • Use advanced search (avoid ‘easy search’) • Medline 1951 to date or 1996 to date • 3 options to search for terms: • Thesaurus mapping • Browse headings • Enter a term Dialog NHS

25. Dialog software • Don’t use punctuation e.g. • Fatigue syndrome, chronic in NLM MeSH • Fatigue syndrome chronic in Dialog • Subheadings • Tree structure • Limits • Show titles Dialog NHS

26. Worked example 1 • Are there any recent papers about SSRIs or SNRIs being used in the treatment of Huntington disease?

30. Worked example 2 • Are there any recent RCTs of the UK-available acetylcholinesterase inhibitors (galantamine, rivastigmine, donepezil) for Lewy Body Dementia?

32. Worked example 3 • Are there any articles which discuss using high dose vitamin supplementation to treat autistic disorders ? • NB – remember that your enquirer’s way of describing what he is asking for may not necessarily be exactly how MeSH describes it….

35. ANY QUESTIONS?