1Mini-manual for Clinical Questions & Ovid Medline SearchingPrepared by UMKC HSL Clinical Medical Librarians Susan Sanders and Kristy SteigerwaltPart I - Clinical Questions & PICO FormatIntroduction:Every patient encounter leads to you asking clinical questions about the patient’s diagnosis,treatment, management, or prognosis. These questions are similar to thinking about aresearch project. They require a well-structured, logical question (hypothesis) followed bya search for information (research), an explanation (discussion) and subsequently, adecision about what action to take (conclusion). It’s no wonder that clinicians needinformation systems to answer questions quickly and accurately. With the deluge ofinformation, it would be unreasonable to do a database search each time you had aquestion, or when seeing a patient. There are systems such as UpToDate, DynaMed, ACPPIER, and others that help you find information and answers rapidly, but there are goodreasons to learn how to search a biomedical databases such as Medline, CINAHL, orPsychInfo, to name a few. What are your database search skills at present? What do youneed to learn about clinical questioning and literature searching?A well-built clinical question usually has four parts, Patient, Intervention, Comparison,Outcome – known as the PICO format. Here are three case examples to work with ondeveloping a PICO question.Case Presentation #1:The patient is a previously healthy, 81-year old woman with a history of progressivedyspnea, leg edema and pallor over the last 3 months. She has no chronic conditions, is onno medications, and requires no assistance. Her exam shows pallor, pitting edema of bothshins, diminished position and vibratory sensation over her feet and ankles, along with theabsence of neck vein distension or S3 gallop. Her chest x-ray is normal. Her test resultsshow very low hemoglobin, an increased MCV (mean corpuscular volume), and a very lowblood level of vitamin B12. What questions would you ask about this patient? Patient, Population or Problem o What are the characteristics of the patient or population? o What is the condition or disease you are interested in? Intervention or exposure o What do you want to do with this patient (e.g. treat, diagnose, observe)? Comparison o What is the alternative to the intervention (e.g. placebo, different drug, surgery)? Outcome o What are the relevant outcomes (e.g. morbidity, death, complications)?
2Case Presentation #2:Mr. Jones is a 55 year old man. He has just been diagnosed with Type 2 Diabetes.Although you regularly prescribe Metformin to help regulate blood glucose levels in newdiabetics, Mr. Jones wants to try using regular exercise and diet to improve his bloodsugar. How will you treat him?Case Presentation #3:The patient presents with a calcium blood level of 17. She is given normal saline andfurosemide. Her condition improves, but what was the cause of her problem? What wouldyou ask?Part II – Searching the Medline Database to Answer a Clinical QuestionMEDLINE is the world’s largest database of indexed journal citations for the healthsciences literature, produced by the National Library of Medicine and National Center forBiotechnology Information in Bethesda, Maryland. Medline is available in numerousdatabases and is a free database through PubMed. There is some free full-text, but notall. Medline is available through Ovid, Scopus, EBSCO, and other publishers with their ownunique interfaces, or “dashboards.”Accessing Medline from UMKC’s Library HomepageTo Access Medline from UMKC, go to the library homepage(http://library.umkc.edu/hslhome), use the dropdown menu and choose “HSL Quick Links”,then select ”Medline Through Ovid”.
3There are many ways to do searches on search engines and in databases. Databaseslike Medline use “controlled vocabulary,” known as MeSH (Medical Subject Headings)terms, Subheadings, and Text Words.What is MeSH? http://www.nlm.nih.gov/mesh/ 1. MeSH is a standardized vocabulary for looking up concepts and terms, and referred to as the MeSH Tree. There are 16 main categories, or descriptors. Think of MeSH like an index in the back of a book where “terms” connect you to “pages.” 2. In reality, there are indexers who really read new articles, and assign MeSH terms. They translate the authors’ non-uniform language into standardized MeSH Headings. 3. To put MeSH to its best use, choose the single narrowest subject heading that corresponds with the information that you are trying to find.Examples:Different Terms, Same MeSHTitle #1, Treatment of gastric cancer.Title #2, Technical considerations in laparoscopic resection of gastric neoplasms.MeSH Heading for both titles: Stomach Neoplasms.Same Term, Different MeSHTitle #1, The diagnosis of plaque-induced periodontal diseases.MeSH Heading: Dental PlaqueTitle #2, Mechanism of senile plaque formation in Alzheimer disease.MeSH Heading: Senile Plaques 4. Indexers also assign various sub-headings to MeSH Headings. Subheading – Secondary topic linked to a MeSH term by an indexer. EXAMPLE: *aortic rupture/su [Surgery] where the subheading is surgery Use a subheading only if it exactly matches a critical topic of your question. No subheading chosen? Then the system searches all of them that the indexer applied. EXAMPLE: Polycystic ovary syndrome/ge [Genetics] = 700+ citations Polycystic ovary syndrome AND Genetics [MeSH Major Topic] = 20 citations
4Strengths of MeSH:Standardization (controlled vocabulary) - Searcher doesn’t have to think or typevariations, like aortic rupture, rupture of the aorta, aortic tear, tear of aorta when usingMeSH.Focus/Major Topic – Find articles where indexer tagged MeSH a major topic; omitcitations where the topic is a minor point. Helps target results, especially in a search foronly 1 topic. When searching two or more topics combined, try without major topic.Subheadings – Indexer can pre-link 2 topics, e.g. Hernia, hiatal/su [Surgery]. MeSH +subheading gets better results than hiatal hernia AND surgery, which incorrectlyretrieves irrelevant citations, e.g., hiatal hernia caused by surgery for reflux disease.Mapping – Mapping is a function of the computer software. It suggests, or matches, yourtyped words to a MeSH heading. For best mapping, type each term separately andcombine your searches. If mapping fails to find relevant articles, or in addition tomapping, search title words, then display MeSH to see what MeSH terms were assigned tothe best results. Ask yourself, “What MeSH did indexers use for this topic?” and go withwhat they used.Weaknesses of MeSH:1. MeSH headings don’t exist for all topics.2. Very recent citations don’t have MeSH yet – indexing takes time.3. Indexers don’t assign MeSH terms to every word in an abstract.4. New MeSH terms are not retroactive, e.g., Individualized Medicine (2010) will not yield any pre-2010 results.5. It is possible to miss the best MeSH terms.MeSH Tree & Explode and Focus in Ovid Medline.Look at the MeSH tree above. If you explode a term, the database searches for yourrequested subject heading and any more specific terms that are related to your subject
5heading. To find out what, if any, narrower topics are associated with your subject heading(so that you can decide whether or not you want to explode your heading) click on theheading itself. You will see a new screen that allows you to view the narrower (andbroader) subject terms associated with your topic. This screen shows subject headings ina "tree" structure. Scroll down to find your subject heading in the tree. The plus (+) signnext to a topic means that the topic has narrower terms associated with it. You can viewnarrower terms by clicking on the plus sign. The number of articles that you can expect toretrieve for each subject heading is provided after each heading.Example Explode: From the subject heading screen you can click directly on "hypertension" to view its tree -related terms that are more general and more specific. If you choose not to explodehypertension, then you will miss articles that are indexed to more specific forms ofhypertension, such as renal hypertension. Instead, you will only retrieve articles abouthypertension that do not mention these more specific forms of the disease.FocusThe focus command tells the database to retrieve only those articles in which your subjectterm is considered to be the primary focus of the article. This will eliminate articles inwhich your topic is discussed only peripherally. You will retrieve fewer (but probably morerelevant) articles if you use this feature.You can explode and focus at the same time. If you check both the explode and focusboxes next to your subject heading, the database will look for all of the exploded terms
6and retrieve articles in which any one of the terms has been designated as the main focusof the article.Which term will explode? Neutropenia or Bird Diseases?SubheadingsMeSH indexers apply subheadings to help further refine your question. The term AnginaPectoris is assigned these allowable subheadings: /di (diagnosis), / th (therapy), /ep(epidemiology), and so on. Agina Pectoris would not be assigned the subheading fortherapeutic use, /tu. Any citation assigned the MeSH term Angina Pectoris could beassigned any or multiple allowable MeSH subheadings, and you need to be careful whenusing subheadings because they limit a search. Here’s an example of how a subheadinglimited and restricted search results ineffectively.The patient presents with syncope, and is taking terfenadine, a "non-sedating"antihistamine. You search for evidence on the risk of syncope in patients takingantihistamines, and perform this Ovid Medline search:Line 1: searches for syncope limited to the subheading etiology (ET).Line 2: searches for Terfenadine and the appropriate group of antihistamines.Line 3: Boolean AND combines the problem (syncope) and your intervention/exposure(antihistamines) and yields 6 citations, none of them relevant.Line 4: backtracking, you run a search filter for etiology or causeLine 5: now search the disease as a key word (mp).Line 6: Boolean AND combination of the search filter, disease, and theintervention/exposure yields 17 citations. Two of these are pertinent including a largeHMO based cohort study.
7The problem with the first search was using the wrong subheading for syncope. In thecohort study that was relevant, syncope carried the subheadings CI (chemically induced)and EP (epidemiology).A search of antihistamines/co (complications) would have found nothing because CO is notan allowable subheading for antihistamines. To find the allowable subheadings use the"tools" function in Ovid. The subheading used in this article for antihistamines was AE(adverse effects).To become familiar with the indexing take a look at the "complete reference" for articleswhich are relevant to your search and you can see exactly which subheadings are used,then use them yourself.SEARCHING WITH TEXT WORDSYou can use words from titles, abstracts, authors’ words, names of studies, etc. if noMeSH matches a topic. Text word searching is a useful supplement to MeSH.Strengths of text word searching - Instantly indexed; up-to-date terminology; every title, abstract word searchable (even low frequency terms); get results even if you miss the best MeSH.Challenge of text word searching - Easy to miss information because authors use different words for the same topic. - Can’t use Explode, Focus, or Subheadings – those features apply only to MeSHExercise: See if you can answers this…based on what you have read this far, wouldyou say Yes or No to the following “Features” when searching with either MeSH orText Word? For example, is Standardization a MeSH or a Text Word feature? Feature MeSH Text Word (Title, Abstract) Standardization YES NO Subheadings Major Topic Explode Latest Terms Fast IndexingFinds Low Frequency Words
8Word variations in text word searching 1. Use a truncation character (*) to search different word endings. o Place an asterisk at the point where the variation begins, e.g. esophag* - retrieves esophagus, esophageal, esophagitis. o Type synonyms and other word variations in search box, connected with OR E.G., Autops* or post-mortem* or postmortem* Typing “or” bypasses mapping and performs a “Multi-purpose” (.mp) search (title, abstract, etc.) – works well for text words. o The asterisk substitutes for a blank space or any number of characters. Can you think of other instances where it would be useful to use truncation? 2. Synonyms: o vitamin C – ascorbic acid o renal failure – kidney failure – renal insufficiency 3. Different spacing and punctuation o RU486 RU 486 RU-486 4. British Spellings o e.g., paediatric* oesophag* 5. Break up phrases o Instead of elder abuse, try abus* AND elder* to retrieve these abuse of the elderly, elder neglect and abuse, partner abuse among the elderly o Hartmann* retrieves hartmann’s procedure, Hartmann resection, Hartmann’s operationGet help with text word variationsSearch MeSH as a major topic then scan results to see word variations in titles.1. Display the MeSH Scope Note2. In Advanced Ovid Medline, Click [i] in Mapping or Tree Display - look at “Used For”Take away: Add text words as safety net for MeSH. When results are important, useboth MeSH and text words.Example MeSH +Text word searchThe MeSH term: “Ebola Vaccines” was established in 2005-add the text word searchesebola AND vaccin* to get pre 2005 results.
9Part III: Putting It Together1. Search each concept/idea/topic separately (most important first).2. Create separate results sets for MeSH and text words.3. Use MeSH mapping; check the Tree display to decide whether to explode; make major topic (focus) decision; check Subheadings for exact match to search topic. Use subheadings minimally.4. Use Text Words – type synonyms, use truncation character, different spellings, spacings, etc.5. Be sure topics in the text word search match topics in MeSH search.6. If MeSH is Major topic, search text words in title only (major point will be found there).7. Use parentheses to avoid logic errors when using AND/OR together, e.g., Ovid: 1 AND (5 OR 8)8. Use Ovid’s key operators & dot commands. Key Operators in Ovid * Find alternate endings to nurs* will find nurse, this word nursing, nurses .tw. Search for this term in the anxiety.tw. Title and Abstract fields Adj Search for one term within patient adj3 will find patient x number of terms from within three words of another anxiety AND Find articles where both smoking AND cessation terms appear OR Find articles where either smoking OR tobacco term appears9. If Ovid “Cannot map,” temporarily un-check “Map to MeSH” box – OR – type a field qualifier after the word in the search box: .mp, .ti These are also called Ovid DOT commands, and more are available in the table (next page).
10 Ovid DOT Commands 110. Full text: First, try “Ovid Full Text” link, if available. If not, click Find it @ UMKC for UMKC full text. Order free through inter-library loan if not available from UMKC in either electronic or print.Last Example! Question: Does dehydration cause delirium at the end of life?