Home care clinicians frequently lack access to medical libraries. Nevertheless, they require ongoing access to current evidence-based nursing literature. The U.S. National Center for Biotechnology Information, at The National Library of Medicine, fills this need with free access to PubMed (http://www.ncbi.nlm.nih.gov/pubmed/), its online database for biomedical and life sciences literature. Over 19 million citations have been entered into this database. To build the database, indexers scan 5,400 journals in multiple languages covering medicine, nursing, dentistry, veterinary science, healthcare management, and preclinical sciences (U. S. National Library of Medicine, 2010a).
PubMed indexers use a controlled vocabulary known as Medical Subject Headings (MeSH®) to describe the content of each journal article entered. There are over 25,500 terms in MeSH®, which is updated annually as new medical terminology emerges (U.S. National Library of Medicine, 2010a). The average article in the database has between 10 and 12 MeSH® terms applied to it.
How does one learn what constitutes a proper MeSH® term? Halfway down the main PubMed page, as shown in Supplemental Digital Content Figure 1, http://links.lww.com/HHN/A1, are three columns of links to resources for better searching. At the top of the right column is the link to the MeSH® Database.
Once in MeSH, the searcher puts a subject in the search box, as shown in Supplemental Digital Content Figure 2, http://links.lww.com/HHN/A1. Keying in the phrase Home Care retrieves nine suggestions including home care agencies, home care services, and home nursing. Each term has a brief definition and a link to the MeSH® page for the individual heading. These definitions are an important part of helping you to choose the correct heading for your search.
For example, a common assumption among home care clinicians would be to select the term Home Nursing because "home care agencies" and "home care services" sound like organizational concepts as opposed to hands-on care. In reality, Home Nursing is defined in MeSH® as nonprofessional care provided by a family member or friend. The term Home Care Services is defined as services "provided by a visiting nurse, home health agencies, hospitals, or organized community groups using professional staff for care delivery" (U.S. National Library of Medicine, 2010b). To search for articles relating to the organizations that provide home health services you would use the term Home Care Agencies.
Proper use of MeSH® terms facilitates a more thorough and focused search than one gets by putting some keywords in Google or Yahoo. Searching Home Care Services and Home Nursing in Google netted over 200 million items each. The links on the first pages for home care services led to information on selecting a home care agency as well as links to specific agencies. The search on home nursing retrieved information on selecting a nursing home plus specific facilities' Web sites.
Exploding in MeSH®
MeSH® is arranged in a hierarchical tree structure. A term may have broader terms ahead of it on the tree as well as more narrow terms branching out below it. Supplemental Digital Content Figure 3, http://links.lww.com/HHN/A1, shows the tree structure for Home Care Services. PubMed will automatically search on Home Care Service as well as all of the terms indented under it unless you put a check in the box next to the phrase "Do not explode this term." The arrow in Supplemental Digital Content Figure 3 shows the location of the box for "do not explode."
Once you have checked a term, go to the Send to Box, as indicated by the yellow arrow in Supplemental Digital Content Figure 4, http://links.lww.com/HHN/A1, and select the option for Send to Search Box with AND. This brings up another box under which is a button for Search PubMed, as indicated by the orange arrow. Clicking that button will retrieve a list of articles on your subject. A June 7, 2010 PubMed search on the MeSH® term Home Care Services retrieved over 34,900 articles with the "explode" option and over 24,100 without the "explode" option.
PubMed offers a variety of ways to reduce those thousands of articles to a more manageable number. At the top middle of the main PubMed page, just above the search box, is the purple link to the page that facilitates invoking limits on your search. (See the upper arrow in Supplemental Digital Content Figure 1.) Clicking on that purple link leads you to the limits page shown in Supplemental Digital Content Figure 5, http://links.lww.com/HHN/A1.
The first and most important option is to limit the publication date of the articles. Those 34,900 articles go back as far as July 1959. The dates menu, indicated by the yellow arrow in Supplemental Digital Content Figure 5, has several established limits as well as the option to select your own date range. Another important limit to invoke is language. PubMed covers journals from all over the world, many of them in languages other than English. Limiting those 34,900 citations to English language published in the last 2 years reduced the number to less than 1,600 articles.
PubMed includes articles from medical, nursing, social work, healthcare management, dental, and veterinary journals. Therefore, another important limit for nurses is the nursing journals group under the Subset options, as noted by the yellow arrow at the bottom of Supplemental Digital Content Figure 5. Invoking the nursing journals limit reduced the English language articles published in the last 2 years to a pool of 421 articles.
The limits page also offers a drop-down menu of article types. There are a variety of research styles, such as validation studies and randomized controlled trials. There are also options for publication formats, such as editorial or case report. Of particular interest to the home care clinician are the options for practice guidelines and patient education handouts. Invoking the practice guideline limit retrieved 11 practice guidelines published in the last 2 years.
With searches on topics such as drug categories or surgical procedures, it is often useful to use the limit for humans to exclude animal experimentation and veterinary journal articles. There are also limits for sex and age groups.
The search results page also offers the opportunity to invoke some more limits. Supplemental Digital Content Figure 6, http://links.lww.com/HHN/A1, shows the first page of results for the search on English language home care services articles from the past 2 years. On the right side of the screen is the note that 187 of those citations are for review articles. Review in PubMed means an article that is a general discussion of a disease or a review of the previously published literature on the subject.
PubMed itself is not a full-text database. However, it does provide links to articles in the public domain that are available elsewhere at no charge. For this search there are 192 free articles available.
Home Care Services
Another way in which a significantly larger pool of articles can be reduced is with the use of subheadings. Most MeSH® terms include a variety of subheading options. As seen in Supplemental Digital Content Figure 7, http://links.lww.com/HHN/A1, standards is one of the subheadings available to use with Home Care Services. To find articles about home care standards, click on the empty box next to standards and then use the Send to menu to select the "Send to search box with AND" option. Do not put a check in the box next to Home Care Services, although it may seem logical. If you do, MeSH® assumes that you want to search either Home Care Services or Home Care Services/Standards, which will retrieve those 34,900 article titles that were received when you searched Home Care Services without using any subheadings. A June 7, 2010 search with just the subheading Standards, limiting the retrieval to English-language articles published in the last 2 years, identified 91 articles.
The last box in the lower right hand corner of the limits page gives you the ability to limit your search to a specific field tag. As you become familiar with MeSH® headings you can select the field tag for MeSH® terms, put your heading in the search box at the top of the page, and go directly to your search results. A list of MeSH® headings useful for home care clinicians appears on the following page (Box 1).
Additional useful field tags include author, full author name, journal, and affiliation. Citations only give the author's last name and initials, so it helps if you know what the author's middle initial is or his or her institutional affiliation. For example, a June 13, 2010 search for articles by Judith S. Young using Young-J with the author tag identified over 5,500 articles. Using Young-JS reduces the retrieval to 167 articles. Imposing the journal subset limit for nursing reduces the items to 5. Three of the articles were written by this author; two of them indicate my affiliation with Abington Memorial Hospital. A search using Young-Judith S and the full author tag retrieved only the three nursing journal articles that were written by this author.
To focus on a specific clinical issue, you may combine the heading Home Care Services with another heading using the Boolean operator "AND." Home care patients often have urinary catheters. To find what has been published recently on urinary catheterization in home care patients, you would return to the MeSH® database and repeat the search process to find the appropriate term. If you put urinary catheters in the search box, you will find that it does not exist as a MeSH® term. However, urinary catheterization is a MeSH® term.
To combine the two sets of search results, Home Care Services and Urinary Catheterization, one can look above the search box on any PubMed page and click on the link to Advanced Search, which is next to the Limits link. (See orange arrow in Supplemental Digital Content Figure 6.) This action brings the screen seen in Supplemental Digital Content Figure 8, http://links.lww.com/HHN/A1. Each previously conducted search appears there with a number beside it. The searches can be combined by keying the relevant numbers with the # sign into the search box, then joining them with the Boolean AND, which must be typed in all capital letters. As shown in Supplemental Digital Content Figure 9, http://links.lww.com/HHN/A1, combining the previously limited output for Home Care Services and Urinary Catheterization resulted in six articles, one of which has the latest Medicare guidelines (Howard, 2009). To see the abstract for this article, click on the underlined title.
To see the abstracts for all of the citations that have been retrieved, you can change the display style. Below the search box at the far left side of the screen is a purple link for Display Settings. Clicking that link brings up a box of display options that includes abstract. Sometimes if you are in need of a quick answer at the bedside, the abstract may provide it. The display options provide another mechanism for identifying useful MeSH® headings. Selecting the option MEDLINE provides you with all of the subject headings that have been applied to each article. The view is in a basic text format so you could easily cut and paste useful subject headings into an ongoing file to facilitate future searching.
If you remember that you saw an article in a specific journal about the topic that you are researching, but cannot remember what issue, PubMed offers a Single Citation Matcher. The link to this template appears at the top of the column for PubMed Tools on the database's home page (see Supplemental Digital Content Figure 1). With Home Healthcare Nurse in the journal box and Eye Diseases in the title box, I retrieved the citation for the article "Age related eye diseases" (Young, 2008).
If you have been unable to identify an appropriate MeSH® heading, you can search by keywords. Because it is not unusual to find multiple words describing a concept or variations in spelling between American and British terms, you should input all of the words, enclosing each in quotation marks. Connect each to the next with the Boolean OR, typed in capital letters. Using the field tag for Title/Abstract may help control the number of citations retrieved.
Managing Your Article Pool
As you review the titles that have been retrieved, you have several options for managing them. For a search that retrieves more than 50 articles, it is useful to do one pass through the titles, clicking in the boxes of the ones that sound most promising. Then change the display from the default summary display to the abstract display. This will show you only the titles and abstracts that you selected. As you read through the abstracts, again click in the box next to the title for the ones that you ultimately hope to read. These citations may then be sent to a file on your computer, e-mailed to yourself or a librarian or moved to a clipboard. If you ultimately want to print the search, select the option "Abstract (text)" from the display menu. Text will enable you to print from a Word document.
DePalma (2005) observed that evidence-based practice "is a natural process for the inquiring home care nurse who wants to provide the highest quality of care" (p. 302). Learning to use PubMed efficiently is crucial for home care clinicians striving to provide high-quality care. Keep a copy of Box 2, "10 Reminders for Searching PubMed," handy until you feel totally comfortable with searching. The PubMed Glossary on this page defines several of the concepts discussed in this article. For more practice in searching PubMed, try its tutorial and Quick Start Guide. They can be accessed from the main PubMed screen shown in Supplemental Digital Content Figure 1 under the column "Using PubMed."
Boolean logic—The system that allows you to combine MeSH terms using "AND" to retrieve articles that must have all of your subjects applied to them. "OR" retrieves documents that have either of the terms you've selected. "NOT" excludes words from your search. It is not used as often as the other two operators.
Explode—A mechanism that allows one to search on a broad MeSH term as well as the more narrow terms located below it in the tree structure.
Field Tags—Identifiers that are applied to each article in PubMed, which allow multiple ways to search the database. They included Author, Affiliation, MeSH term, Investigator, Journal, Substance Name, Grant Number, and Text Word.
Limits—A variety of options that can be applied to a search to help narrow the retrieval of the article pool. They include Dates, Language, Journal Subset, Type of Article, Ages, and Field Tags.
MeSH—The National Library of Medicine's controlled vocabulary database from which all indexing terms are selected.
Review Article—A journal article that is a systematic literature discussion on disease management, clinical guidelines, a nursing model, or other broad subject. It may also synthesize a number of clinical trials or series of case reports.
Subheadings—Qualifiers applied to MeSH terms that are used to focus on an aspect of a MeSH concept. They include terms such as Epidemiology, Adverse Effects, Standards, Drug Therapy, and Methods.
Tree Structure—The hierarchical mechanism MeSH uses to relate terms to topics that are broader and narrower than they are.
DePalma, J. A. (2005). Using evidence in home care: The value of a librarian—clinician collaboration—the clinician's role. Home Health Care Management & Practice, 17
Howard, M. (2009). U.S. Medicare policy change in catheter guidelines improves patient care in home and hospice setting. Caring, 28
at U.S. National Center for Biotechnology Information, National Library of Medicine. (2010). PubMed. Available
from U.S. National Library of Medicine. (2010a). Fact sheet
Medical Subject Headings (MeSH®). Retrieved
from U.S. National Library of Medicine. (2010b). MeSH® database. Retrieved
Young, J. S. (2008). Age related eye diseases: A review of current treatment and recommendations for low-vision aides. Home Healthcare Nurse, 26
PubMed Searching for Home Care Clinicians: A Guide for Success in Identifying Articles for a Literature Review
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PubMed Searching for Home Care Clinicians: A Guide for Success in Identifying Articles for a Literature Review
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CE TEST QUESTIONS
GENERAL PURPOSE: To provide registered professional nurses with information on how to use PubMed efficiently to identify and access peer-reviewed articles that support evidence-based practice.
LEARNING OBJECTIVES: After reading this article and taking this test, you should be able to:
- Review the background information necessary for understanding what PubMed is and what it includes.
- Apply the information presented here to using PubMed to retrieve articles on a specific topic of interest.
1. PubMed is the online database for which of the following branches of the National Library of Medicine (NLM)?
a. Division of Specialized Information Services
b. Office of Computer and Communications Systems
c. National Center for Biotechnology Information
d. National Center for Biomedical Communications
2. How many citations have been entered into PubMed?
a. more than 19 million
b. about 26 million
c. just over 32 million
d. at least 40 million
3. MeSH® is a
a. synthesis of clinical trials or case reports.
b. list of qualifiers used to focus on an aspect of a concept.
c. hierarchical mechanism that relates terms to topics.
d. controlled vocabulary database of indexing terms.
4. According to the NLM definitions, which of the following phrases would be most useful in finding information about the care home health nurses provide?
a. home nursing
b. home care services
c. home care agencies
d. home care
5. In PubMed, "exploding a term" means
a. deleting the term.
b. limiting the search results.
c. sending the term to the search box.
d. searching on all the terms indented under the term.
6. Recently, a full PubMed search on "home care services" retrieved
a. nearly 15,400 articles
b. about 20,000 articles.
c. over 34,900 articles.
d. just under 50,000 articles.
7. The most important search limit option sets limits based on the
a. date of publication.
b. professional field.
d. research style.
8. An example of a journal group choice included in the PubMed limits page under "subsets" is
a. healthcare journals.
b. nursing journals.
c. medical journals.
d. veterinary journals.
9. An especially useful format option for home care clinicians to select within PubMed is
b. legal cases.
c. practice guidelines.
d. technical reports.
10. To find just the articles indexed under a subhead of the original search topic, the recommendation is to
a. check the original search topic again.
b. check only the subtopic.
c. check both the original and the search topics.
d. start a new search.
11. The last box in the lower right hand corner of the limits page allows limiting a search to
a. ages of subjects.
b. clinical trials.
c. abstracts only.
d. specific field tags.
12. The tool to use to combine two sets of search results is labeled
a. "advanced search."
b. "clear history."
c. "clinical queries."
d. "all fields."
13. The tool to use to retrieve an article in a specific journal without knowing which issue it appeared in is labeled
a. "batch citation matcher."
b. "journals database."
c. "topic-specific queries."
d. "single citation matcher."
14. When searching by keyword using two similar terms, which of the following should be inserted in the search field between the words?
c. a comma
d. a period
15. When a search retrieves more than 50 articles, it is useful to
a. repeat the search with fewer limits.
b. select the most promising articles.
c. print the list in a Word document.
d. change the display to "summary."
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