Literature Searches by Computer Vaughn G . Sinclair

This article informs nurse researchers of the advantages of learning to pclform their own computerized literature searches. Hardware and soBware require- ments for long-distance data retrieval are discussed. A variety of jnancially feasible means of wcessing health-related dntabases are presented along with technologic trends related to online retrieval systems.

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N urse researchers and health care practitioners are confronted with an explosion of published research and health-related literature. Naisbitt (1982) reports that worldwide approximately 6,000 to 7,000 scien-

tific articles are written daily, that scientific knowledge is doubling every 20 months and that the rate of information generation will increase greatly in the near future. Computerized databases store information to facilitate rapid retrieval of perti- nent information. As a result of the growing crisis in collecting and organizing health care information, this tool for.scanning the literature demands our attention. The advantages of learning to use computerized literature searches and recently developed options for searching health-related literature are discussed.

Advantages of Computer Searches The large databases of interest to most nurses are the Psycho-

logical Abstracts (PsycINFO), MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and the Educational Resources Information Center (ERIC) databases. The advantages over comparable manual research methods (e.g., manually searching through health-related indices or locat- ing articles referenced in pertinent articles) are numerous:

Time Saving. A list of relevant citations may be obtained much more quickly through a computerized search. A skilled data- base searcher can produce an accurate, relevant, exhaustive search within minutes. One source shopping. A vast amount of information may be obtained from one source, as opposed to searching manually through several indices. MEDLINE, for example, corres- ponds to the International Nursing Index and the Index Medicw. Currency. The computer databases are updated more quickly than are the printed indices. More options on search categories. The researcher is not limited to subject or author searches but may extract information by journal name, publication year or specific words in a title. For example, a nurse could procure a list of every article with the word “bypass” in the title published during a given year or in a given journal. Other categories of citations such as abstracts may also be scanned by the computer. Ability to link concepts. The researcher may link several concepts

in a search strategy to narrow quickly the focus of the search. This is the primary advantage of computerized searching. Key terms that define the search topics are entered into the database, and the computer combines the sets of terms and extracts only those citations relevant to all the terms. This process, the basis for efficient online searching, eliminates the duplicated and tedious efforts necessitated by manual cross- referencing in indices.

Financially Feasible Options for Accessing MEDLINE

MEDLINE is the most comprehensive index to national and international health-related literature. Its database includes cita- tions from more than 3,000 international journals published in the United States and 70 other countries. The journal articles that are indexed include biomedical topics, nursing, dentistry, health care delivery and chemicals and drugs as well as the humanities and information science as they relate to health care.

The primary disadvantage associated with the computerized search is the expense, If a librarian is paid to conduct the search, the local fee is $15 per topic searched. Furthermore, MEDLINE is divided into several files, and literature indexed before 1981 requires searching MEDLINE’s backfiles which entails an extra charge per backfile searched. Because of the expense of paying librarians to search and the fact that nurses who are trained in literature searching could probably personalize their own searches more effectively, nurses who must keep abreast of the literature should consider a variety of more economical and effective means of accessing MEDLINE (Clark & Clark, 1985).

MEDLINE may be accessed through the National Library of Medicine’s (NLM’s) MEDLARS system or through large com- mercial database systems such as DIALOG in Palo Alto, Califor- .nia, and Bibliographic Retrieval Service (BRS) in Latham, New York. The commands used to manipulate the database vary from system to system, although specialists have proposed standards for a common command language that could be used with any commercially available database (Hildreth, 1986). Within the next decade, because of the intensity of artificial intelligence research, searchers will probably be able to converse with pro- fessional databases such as MEDLINE in everyday parlance, termed “natural language querying” (Howitt & Weinberger, 1984). Until that capability is available, however, searchers must communicate with required command languages that usually have precise and rigid syntax requirements.

Access to MEDLINE through the NLM’s system is relatively inexpensive at $22 per connect hour during prime time (1O:OO

VAUGHN G. SINCLAIR, R.N. Ph.D. lota, is Assistant Professor of Nun- ing Administration at Vanderbilt University. Correspondence t o School o f Nursing, Vanderbilt University, Nashville, TN 37240. Accepted for publication December 1,1986.

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a.m. to 5:OO p.m. Eastern Standard Time, Monday-Friday) and $15 per connect hour during nonprime time. These rates may sound exorbitant, but a well-trained searcher could conduct an extensive search in 15 minutes, which would cost only $3.75 during nonprime time. The NLM permits only trained searchers to use its database, so an interested nurse must enroll in an 8- hour course to learn the concepts and skills needed to search on the NLM system.

These training courses for health professionals are taught by medical librarians in various locations throughout the country. For a list of certified trainers, contact the MEDLARS Manage- ment Section on their toll-free number or at the National Library of Medicine (8600 Rockville Pike, Bethesda, MD 20894). Course participants are taught how to contact the MEDLINE database using telecommunications services such as TELENET and TYMNET, how to logon to the NLM computer system and how to enter key words or descriptors that define the search topics of interest. After the descriptors are entered in the NLM computer, it compiles a list of bibliographic citations that match those descriptors. A set of citations that represents combined aspects of a subject can be produced by combining descriptors. The descriptors represent subject categories, which are arranged by NLM in a thesaurus of terms called Medical Subject Headings (MESH). The MESH terms are compiled in an alpha- numeric hierarchical structure, which NLM calls “tree struc- tures.” The “trees” arrange terms from broad generalities to very specific concepts (Stoia, 1983). Nurses who would perform their own MEDLINE searches should purchase or have access to the current year’s thesaurus of acceptable descriptors published in two books-the Medical Subect Headings: Annotatcd Alphabetical List and the Medical Subject Headings: Tree Structures. Both books are available from the MEDLARS Management Section at the above address. These tools help the searcher obtain the sensitive, accurate descriptors so essential for an effective search (Fox & Ventura, 1984).

Upon completion of the NLM training course, participants are eligible to apply for passwords and open accounts to search databases available from the MEDLARS system. In addition to MEDLINE, the MEDLARS system at NLM offers several specialized health-related databases (Sparks, 1984) including CANCERLIT (index to cancer-related literature) and HEALTH PLANNING AND ADMIN (dealing with health planning, organization, financing and management). Users of the system are billed for online connect time and telecommunica- tions charges (at a minimum hourly rate of $15) plus additional charges if offline printing copies are made. To save money, searches may be “downloaded” or relayed from the large com- puter to a floppy disk and reviewed after the costly telephone connection is terminated. Commercial Vendor Sources

Large commercial data services offer access to MEDLINE at reduced rates during nonprime-time hours (evenings and week- ends). Principles used to access these systems are similar to those used for NLM, but specific commands required by each system vary. In general, these nonprime-time services are so easy to use that they require no formal training. Costs may vary, but at present there is a $95 initial subscription fee for the discount rates of BRS/After Dark, which is available from 6:OO p.m. local time to 4:OO a.m. Eastern time, seven days a week and has a minimum monthly charge of $12. MEDLINE connect time rates are $24 per connect hour for the After Dark service. BRS/After Dark offers access to several health-related bibliographic data- bases including MEDLINE, Nursing and Allied Health Litera- ture, Psychological Abstracts, and Health Planning and Administration. The Nursing and Allied Health Literature data- base (called CINAHL on other systems) indexes 250 journals, all

nursing periodicals published in English, as well as many allied health publications.

BRS Colleague is a separate service of the BRS system that offers more than bibliographic citations for a monthly minimum charge of $15. Colleague offers a unique complete text library of medical reference books, journals and periodicals at $32 per con- nect hour during prime time (6:OO a.m. to 6:OO p.m. local time on weekdays) and $20 per connect hour on weekends. Examples of online journals include The Lancet and The New England Journal of Medicinc, but as yet no nursing journals or books are available in full text.

The DIALOG Information Retrieval Service in Palo Alto offers more than 300 databases to the user including MEDLINE, ERIC and PsycINFO. Their Knowledge Index service (available from 6:OO p.m. to 5:OO a.m., local time, Monday through Fri- day, and selected hours on weekends) is also fairly simple to use. Knowledge Index does not exact an initial subscription fee; nor does it require a monthly minimum charge. Not all of DIA- LOG’S databases are accessible through Knowledge Index, but those that are include MEDLINE, ERIC and PsycINFO at a connect time rate of $24 per hour (or $.40 per minute).

Grateful Med Grateful Med is a recently developed specialized software

package on a floppy disk and is designed to search the MEDLINE database, permitting health care professionals to use personal computers to search MEDLINE without formal train- ing on MEDLINE access. Before you connect with the com- puter, this program prompts you for the needed information so that it can designate descriptors for the search. Grateful Med then does all of the work of communicating with MEDLINE on the NLM system. While this specialized software package may be easy to use, it will not be as thorough or effective at exploring the database as you yourself would be. For those who cannot expend the time and effort to learn to search MEDLINE, Grate- ful Med offers assistance in searching the database. Grateful Med may be used on an IBM PC or compatible machine equipped with a Hayes or compatible modem.

Hardware and Software Requirements In order for your microcomputer to access these arsenals of

information, five items are needed: (a) a telephone line, (b) a communications card (an RS-232 serial cardadapter), (c) a modem, (d) a cable to connect the modem and the serial card, and (e) communications software. The serial card, which is sometimes included as standard equipment, is necessary to trans- late the computer’s natural “parallel communication” into “serial communication” so that it can be transmitted over the phone line. Computers process information in a series of eight binary digits (or bits) that represent electronic impulses. These eight bits are arranged in different formations to represent differ- ent characters, or bytes. All eight bits travel together along eight parallel wires inside the computer. To travel along the telephone line, the bits must be transformed into a single-file sequence, a transformation managed by the serial card.

In addition, phone wires can carry only sound waves, so the computer’s electronic bits must be further transformed into sound waves by the modem and then transmitted over the phone lines. The modem, an acronym for modulator/demodulator, modulates the electronic bits into sound and performs the reverse function for data entering the computer through the phone line. Types of Modems

Modems may be internal or external to the computer. Internal modems are circuit boards designed for insertion into the micro- computer’s expansion slot, although technologic advances in the miniaturization of modems may in the future eliminate the need

36 IMAGE: Journal of Numng &holanhip

for expansion slots. Internal modems are usually cheaper since they are packaged with communications software and do not require serial communications adapters or cables. They require less desk space but are usually brand-specific (i.e., an internal modem designed for an Apple would not work on an IBM- compatible machine; should the owner decide to purchase a new computer, this should be kept in mind). In contrast, external modems, whether connected directly or through acoustic cou- pler, require the purchase of a serial communications adapter and a cable as well as communications software. For a discussion of other features of modems and data transmission, the reader is referred to Maher’s (1984) excellent article on the technicalities of long-distance data transmission.

Baud Rate The speed at which data are communicated is qeasured by the

number of signals (bits) that are sent or received by a modem every second and termed the baud rate. Bits per second (charac- ters per second) and baud rate are used interchangeably (but actually have slightly different definitions). The speed of data transmission is an important factor in determining the price of the modem. The two most prevalent baud rates available in modems are the 300-baud and 1200-baud rates (the 1200-baud, of course, sends data approximately four times faster than does the 300-baud). The more expensive, faster modem may be more cost effective since it can obtain data far more quickly from large computer databases, thus trimming the cost of the expensive long-distance connect time. In keeping with the trend toward faster communications technology, 2400-baud transmission is becoming more widespread, with 4800-baud probably becoming commonplace by 1990 (Howitt & Weinberger, 1984).

Hayes compatibility is a desirable feature for modems since many popular communications software packages require full Hayes compatibility to function efficiently. If an external modem is purchased, communications software packages must be evalu- ated for purchase. Important features to consider include (Saffady, 1985):

Setup menus to establish communication parameters, which may be saved and used repeatedly.

0 Automatic dialing and logon procedures. Unattended reception so that the computer may be controlled by a remote user. Ability to perform file transfers of text files (only characters) and binary files. Error-checking protocols for file transfer to ensure the accu- rate transmission of data. Flexible printer controls (hard copy of online session and the ability to browse back through a previously recorded search).

Benefits of Online Searching Skills Learning to access MEDLINE is a useful skill for nurses to

acquire for a number of reasons. Facility with information exchange via computers will be a needed skill in the future as health care professions become increasingly dependent on com- puters to filter information from the environment and organize new knowledge. In addition to accessing large computer data- bases such as MEDLINE to update their knowledge base, as more personal resource-sharing networks are developed on com- puters, nurses will use computers and telecommunication sys- tems to access specialized resources and colleagues (Armstrong, 1985). Health-related computer “bulletin boards” have been established across the country. Health professionals with similar interests access these bulletin board networks for informal infor- mation exchange. The networks may be accessed with micro- computers, allowing a nurse to post a message that may be read by all who access the bulletin board. Professionals or interest groups use the boards, usually free of charge, to attain knowl-

edge about professional issues or share ideas, facts and research interests. In addition to free-standing bulletin boards, large commercial information utilities such as the SOURCE and COMPUSERV offer health care information to the general pub- lic and networking services to groups of health care professionals who want to share information through computerized bulletin boards. A group of health care professionals maintains a bulletin board on the COMPUSERV system titled MedSIG, which posts a list of free-standing health-related bulletin boards available across the country.

In the future, the use of computers and telecommunications services to transmit clinical information will increase markedly as nurses use computers to transmit data long-distance in their clin- ical practices (Loepprich & Smith, 1983-1984). Computers will be used increasingly to transmit data from remote monitoring systems in patients’ homes, to transmit data for consultation pur- poses and to transmit patients’ medical records (Charbonneau, 1982; Higgins, Conrath, & Dunn, 1984). Matheson and Cooper (1 982) envision house calls via satellite-mediated telecommunica- tions systems that permit two-way audiovisual and digital confer- ences between the health care provider’s office and the patient’s home. In the near future, sophisticated decision support systems using artificial intelligence may be accessed by nurses who seek their advice on particular clinical actions (Ozbolt, Schultz, Swain, & Abraham, 1985; Wright, 1985). Since the use of com- puters and telecommunications for the transmission of health- related information will dramatically increase in the next decade, nurses should begin using computers for long-distance database access when the benefits of such access outweigh the efforts required to learn the skill. Accessing MEDLINE is a time-saving and efficient method of obtaining professional information. Cost-effective means of accessing this database exist and may be explored by nurse professionals. Nurses who spend the time and energy required to access and search professional databases will be rewarded with fruitful searches and primed to take advantage of clinical applications for long-distance database access in the future. 8

References

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Charbonneau, L. (1982). Telehealth: Making health care truly accessible in the North. Canadian Nurse, 78, 18-23.

Clark, M. J., & Clark, P. E. (1985). Personal computers and database access. Image, 17, 21.

Fox, R. N. , & Ventura, M. R. (1984). Efficiency of automated literature search mecha- nisms. Nursing Research, 33, 174-177.

Higgins, C. A, , Conrath, D. W., & Dunn, E. V. (1984). Provider acceptance of telemedicine systems in remote areas of Ontario. Journal of Family Practice, 18, 285-289.

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