Searching Medline

1. Searching Medline Helen Rowlandson Principal Medicines Information Pharmacist London Medicines Information (Northwick Park) London

2. Jan 2008 course - participants responses • 21 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 Ovid • Of the Dialog users most use Advanced search option

3. Main issues/problems • Searches produce too many hits - how do you narrow your search down? • Searches produce irrelevant hits – how to you find relevant hits for your topic? • Searches produce no hits – why is this? • Finding/deciding which are the relevant search terms to use –use of the MeSH browser/ MESH descriptors/MESH headings/thesaurus • What to do if a drug name isn’t a MESH heading • Using search terms across both Embase and Medline • Use of explode function, major descriptors and subheadings

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. Plan • Searching basics – a refresher • What is Medline? • Medical Subject Headings (MeSH) • NLM’s MeSH browser • Searching tools • 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 • 5,000 journals indexed, 70 countries

9. Searching Medline • Use indexing system - MeSH thesaurus • Controlled vocabulary with ~23,000 descriptors • Each represents a single concept • Tree structure - hierarchal • Constantly changing • 600+ added per year

10. Medical Subject Headings • 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. 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” NLM MeSH Browser

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

13. 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 NLM MeSH Browser

14. 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

15. 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

16. 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

17. 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

18. 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)

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

20. Medline & MeSH Recap • Successful searching is finding correct indexing term • MeSH headings • Scope Notes • Focus/Explode • Subheadings/Check Tags • Supplementary concepts

21. Accessing Medline? SILVER PLATTER PUBMED MEDLINE OVID DIALOG NHS MEDSCAPE

22. 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

23. Dialog software • 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

24. 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

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

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

28. 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….

31. ANY QUESTIONS?