Finding Information by “Design”: Search Strategies for Cardiothoracic and Vascular Anesthesia Literature

Abstract

CARDIOTHORACIC AND VASCULAR anesthesia is a dynamic field with a strong emphasis on evidence-based care. Efficient literature searching is an indispensable tool for medical practice, research, and education. The practice of evidence-based medicine requires the integration of the best available evidence with patient conditions and preferences to guide clinical practice every day.1Heneghan C. Badenoch D. NetLibrary I: Evidence-based Medicine Toolkit.in: (ed 2). Blackwell Publishing, New York2006: 65Google Scholar However, keeping up with the literature has become an increasingly difficult task for the busy practicing physician. The amount of medical information available has increased exponentially. It is estimated that the average physician uses 2 million pieces of information to practice medicine.2Wyatt J. Use and sources of medical knowledge.Lancet. 1991; 338: 1368-1373Abstract PubMed Scopus (164) Google Scholar There are 7 million pages of information added to the World Wide Web every day.3Reich V. Rosenthal D. Preserving today's scientific record for tomorrow.BMJ. 2004; 328: 61-62Crossref PubMed Scopus (8) Google Scholar “Information overload” is being recognized as a prevalent problem.4Hall A. Walton G. Information overload within the health care system: A literature review.Health Info Libr J. 2004; 21: 102-108Crossref PubMed Scopus (122) Google Scholar In 1996, Waddington reported that information overload was leading to stress and tension within the work environment, resulting in longer working hours, loss of job satisfaction, decrease in social life, tiredness and illness, and a degradation in personal relationships.5Waddington P. Dying for Information? A Report on the Effects of Information Overload in the UK and Worldwide. Reuters, London1996Google Scholar The report underscored the need to take information management seriously. This has led to a growing realization among the medical community of the importance of acquiring and teaching information management skills. Traditionally, physicians have relied on textbooks, journal articles, and advice from colleagues when faced with a clinical question.6Stinson E.R. Mueller D.A. Survey of health professionals' information habits and needs Conducted through personal interviews.JAMA. 1980; 243: 140-143Crossref PubMed Scopus (181) Google Scholar However, this may not yield the most accurate or most current information. Reports indicate that general practitioners usually underestimate their information needs.7Covell D.G. Uman G.C. Manning P.R. Information needs in office practice: Are they being met?.Ann Intern Med. 1985; 103: 596-599Crossref PubMed Scopus (665) Google Scholar This is probably true of every specialty in medicine. To better manage information, clinicians need to understand the basic concepts underlying the different types of literature, appreciate their strengths, and know how to find the literature that will best meet their needs. A large number of health care professionals also use search engines like Google and Yahoo for information on biomedical literature. Searches in Google Scholar retrieve results that include scholarly literature citations as well as books, abstracts, and material from other scholarly organizations. When using a search engine, using quotes to indicate phrases (eg, “perioperative outcome”) and using advanced search options usually yield better results. However, clinicians needs to be aware of the shortcomings of using a search engine for complicated biomedical searches. One of the drawbacks is that relevance ranking is based on characteristics of the Web page and not on an assessment of its meaning (eg, medical subject headings [MeSH] terms). Search engines also are not usually as amenable to complex searches as bibliographic databases.1Heneghan C. Badenoch D. NetLibrary I: Evidence-based Medicine Toolkit.in: (ed 2). Blackwell Publishing, New York2006: 65Google Scholar There are many tools to facilitate the practice of evidence-based medicine including systematic reviews, users' guides to medical literature, strategies to improve quality of literature searches, and online resources to get high-quality information for point-of-care use. These tools are often poorly understood and, thus, improperly used. In addition, residency programs offer inadequate education on the use of these tools. Understanding that some information is freely available whereas other information requires a subscription (personal or institutional) is also an important distinction and may determine which database physicians use to search for information. In this article, the authors describe guidelines for the efficient and effective use of biomedical information tools, strategies to increase the yield of relevant material during literature searches, electronic tools available to the busy practicing anesthesiologist, and a practical solution to integrating information management in the curriculum for medical students and residents as well as for faculty development programs. The methodology behind evidence-based medicine and the process of critically evaluating published literature are beyond the scope of this review and will not be discussed here; they are described very well elsewhere.1Heneghan C. Badenoch D. NetLibrary I: Evidence-based Medicine Toolkit.in: (ed 2). Blackwell Publishing, New York2006: 65Google Scholar, 8Moyer V.A. Elliott E.J. Gilbert R. Evidence Based Pediatrics and Child Health. (ed 2). BMJ Books, London2004: 565Google Scholar, 9Simpson F. Doig G. Efficient literature searching: A core skill for the practice of evidence-based medicine.Intensive Care Med. 2003; 29: 2119Crossref PubMed Scopus (67) Google Scholar, 10Guyatt G. Users' Guides to the Medical Literature: Essentials of Evidence-Based Clinical Practice. (ed 2). McGraw-Hill Medical, New York, NY2008: 359Google Scholar When faced with a scenario in which more information is needed, it is helpful to follow a systematic, step-by-step approach to get the information desired in the most efficient and effective process. The physician begins by creating a structured, answerable question. It may take some time to actually distill the question into component parts.10Guyatt G. Users' Guides to the Medical Literature: Essentials of Evidence-Based Clinical Practice. (ed 2). McGraw-Hill Medical, New York, NY2008: 359Google Scholar, 11Schardt C. Fesperman S. Dahm P. et al.How to perform a literature search.J Urol. 2008; 179: 1264Abstract Full Text Full Text PDF PubMed Scopus (46) Google Scholar, 12Graham A.M. Finding, retrieving and evaluating journal and web-based information for evidence-based optometry.Clin Exp Optom. 2007; 90: 244-249Crossref PubMed Scopus (10) Google Scholar However, it is important to get as specific as possible with the question so that the clinician can get relevant results from the literature search. A good question has 4 essential parts to it, which are best remembered by the following mnemonic PICO.1Patient population: The patient or the population who has similar attributes to your patient.2Intervention (or exposure): What happens or is done to that population. It might be an intervention or an exposure.3Comparison: A well-defined comparison group that experiences a different intervention/exposure or no intervention/exposure.4Outcomes: The outcomes (eg, morbidity, mortality, quality of life, cost, and length of hospital stay) that are likely to be most important to patients, policy makers, service providers, or clinicians. Having structured the question, the next step is to identify the type of question. Some common types of questions are as follows:1Intervention or therapy: What will be the effect of a particular intervention on the patient?2Diagnostic accuracy or differential diagnosis: What is the likelihood that one disease or another is causing the condition? What is the accuracy of a particular diagnostic test?3Prognosis: What will be the likely long-term outcome of a particular intervention or therapy?4Harm: How might the intervention cause harm?5Baseline risk: What is the risk that someone within a particular population will develop a condition? Once the clinician determines the type of question he/she is asking, he/she needs to identify the study design(s) that will best help answer it8Moyer V.A. Elliott E.J. Gilbert R. Evidence Based Pediatrics and Child Health. (ed 2). BMJ Books, London2004: 565Google Scholar, 10Guyatt G. Users' Guides to the Medical Literature: Essentials of Evidence-Based Clinical Practice. (ed 2). McGraw-Hill Medical, New York, NY2008: 359Google Scholar (Table 1). The type of question will determine the type of literature that will yield the desired information. Each type of literature has its own pros and cons:1Systematic review: A systematic review uses an explicit and reproducible methodology to identify, appraise, and summarize primary studies. The methodology must state specific objectives, materials, and methods used. Although a systematic review may contain a meta-analysis, a meta-analysis is not always a systematic review. A meta-analysis reviews data from a number of studies and provides a statistical interpretation of whether the intervention is useful or not. A systematic review is distinct from a meta-analysis because of the stringent methodology (eg, The Cochrane Library).2Critically appraised topic (CATs): A critically appraised topic begins with a question. Relevant literature is then retrieved and synthesized. Risks, benefits, and cost for each treatment option are weighed with the available evidence. Multiple critical appraisals may be distilled into larger CATs (eg, CAT Crawler).3Randomized clinical trials (RCTs): An RCT is a study of the effect of therapy on real patients. The methodology includes minimization of bias (randomization and blinding) and comparison of defined variables and outcomes between groups (different interventions including no intervention). Limitations are usually associated with methodology problems (eg, ARDSnet trial for low-tidal-volume ventilation).4Cohort studies: Cohort studies involve a large population that is followed for a period of time. Patients are grouped by the presence or absence of a particular clinical condition or by having (or not having) received a particular treatment regimen. There is no attempt to stratify other variables, and the 2 groups may be significantly different because of this (eg, Framingham Heart Study).5Case-control studies: Case-control studies involve patients with a specific clinical condition who are “matched” with patients who do not have the condition. The matching points include age, sex, associated diseases, and so on. These studies may be prospective or retrospective. Retrospective studies may be confounded by incomplete medical records and patient recall issues. Showing a statistical relationship does not necessarily indicate causation (eg, early studies examining the relation between tobacco smoking and lung cancer).6Cross-sectional study: A cross-sectional study observes a defined population at a single point in time or time interval. Exposure and outcome are determined simultaneously. This type of study is used to determine the incidence and prevalence of disease in a particular population.7Case reports and case series: Case reports and series are presentations of the treatment of a single patient or small group of patients. There is no statistical validity because there is no group for comparison. These reports can be helpful in identifying a question that should be evaluated and answered. They play an important role in the discovery of new diseases and unexpected side effects of new drugs. They played an important part in the epidemiology of West Nile encephalitis in New York and tracing the spread of the Severe Acute Respiratory Syndrome (SARS) epidemic.8Expert opinion: An expert opinion is a summary of findings reflecting current thinking on the topic written by a recognized expert in the field. When using these resources, it is important for clinicians to consider whether the author used a thorough and systematic process to gather information used to formulate their findings, opinions, and recommendations. Not every resource clearly identifies this information (eg, physician-authored information and advice on conditions and treatments in resources such as UpToDate or eMedicine).Table 1The Best Sources To Find Information Regarding Different Types of Questions8Moyer V.A. Elliott E.J. Gilbert R. Evidence Based Pediatrics and Child Health. (ed 2). BMJ Books, London2004: 565Google Scholar, 10Guyatt G. Users' Guides to the Medical Literature: Essentials of Evidence-Based Clinical Practice. (ed 2). McGraw-Hill Medical, New York, NY2008: 359Google ScholarQuestion TypeBest SourcesInterventionRCT and systematic reviews, cohort studies, case-control studies, case seriesDiagnosisRCTPrognosisCohort studies, case-control studies, case seriesHarmRCT, cohort studies, case-control studies, case seriesAssessing baseline riskCohort or cross-sectional design Open table in a new tab The next step is to identify the database or resource that contains the type of literature needed to answer the question. Once the clinician has determined which type of study or literature will help answer their question, they need to understand which resources to use to obtain that type of literature. Most relevant resources for searching the biosciences literature are now available online. Although many resources offer reviews, synopses, and studies, most of the topics are directed at clinicians in internal medicine. Following is a list of databases that are useful to the cardiac anesthesiologist. The resources are listed based on the type of literature they index and collect. The following resources list systematic reviews, CATs, and guidelines (Table 2):1Cochrane Database of Systematic Reviews: This resource was created by the Cochrane Collaboration and contains more than 1,300 systematic reviews along with the protocols of reviews currently in progress. The systematic reviews in the Cochrane database include interventions (therapy). These are very comprehensive reviews and can be found via various search engines such as Ovid, PubMed, TRIP Database, SumSearch, and the Cochrane site. The Cochrane Database also includes the Cochrane Anesthesia Group (http://www.carg.cochrane.org/en/index.html), which produces reviews in the following 8 areas of anesthesia: (1) ambulatory anesthesia and anesthesia outside the operating room, (2) anesthesia and medical disease, (3) drugs in anesthesia and intensive care medicine, (4) perianesthetic and perioperative care medicine, (5) postanesthetic unit and intensive care unit, (6) prehospital medicine, resuscitation, and emergency medicine, (7) regional anesthesia, (8) technology in anesthesia and intensive care medicine. This is a great resource when faced with a common clinical question that has to be answered in a limited time.13Moller A.M. Smith A.F. Pedersen T. Evidence-based medicine and the Cochrane Collaboration in anaesthesia.Br J Anaesth. 2000; 84: 655-658Crossref PubMed Scopus (13) Google Scholar The reviews are periodically updated; however. it is good practice to look at the date of last update and deduce if the conclusions are still relevant at the time they are needed.2DARE (Database of Reviews of Effects): This is a free database consisting of critically appraised summaries of non-Cochrane systematic reviews. It contains more than 6,000 quality-assessed reviews. DARE is produced by the reviewers and information staff of the National Health Services' Centre for Reviews and Dissemination at the University of York, England, and consists of structured abstracts of systematic reviews from all over the world. DARE records cover topics such as diagnosis, prevention, rehabilitation, screening, and treatment. The abstracts are accompanied by a commentary indicating the strengths and weaknesses of the process used for the review. The database contains more than 500 abstracts related to the practice of anesthesia.3PIER (Physician Information Education Resource): Provided by the American College of Physicians (ACP), this resource offers compendia of evidence on the effects of common clinical interventions, providing explicit recommendations. PIER has a number of synopses related to cardiac anesthesia such as perioperative management of congestive cardiac failure (Fig 1), rhythm and conduction abnormalities, and perioperative management of diabetes mellitus.4Clinical Evidence: Clinical Evidence, from the British Medical Journal, provides information on therapies for numerous conditions; however, this resource focuses on summarizing the strength of the evidence available for benefits and harms of specific treatments. Clinical Evidence uses systematic reviews, RCTs, and observational studies to find the best evidence available regarding therapies. If no good or conclusive evidence exists for a treatment, it will indicate this as well. Rather than suggest or promote specific interventions, physicians are encouraged to examine the evidence for each therapy to decide what action to take. Information on new evidence for each condition is updated every 6 months.5US National Guidelines Clearinghouse (NGC): This resource contains both US and international evidence-based clinical practice guidelines. The NGC also groups guidelines that cover similar topics and offers synthesis of these. In addition, clinicians can find expert commentary of important issues related to the development, use, and attributes of clinical guidelines in general.Table 2Systematic Reviews, CATs, and Guidelines⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.ResourceVendor/SupplierAvailabilityCostURLCochrane Database of Systematic ReviewsCochrane CollaborationCan be searched using:⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.Wiley InterScience Cochrane site⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.PubMed⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.Ovid MEDLINE⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.Scopus⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.TRIP (Turning Research into Practice)⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.SumSearchAbstracts are free, but not full records. Provides institutional licenses or user can access individual reviews on a pay-per-view basis. Access is for 24 hours.http://www.cochrane.org/reviewsDARE (Database of Reviews of Effects)A stand-alone resource included in the Cochrane LibraryCan find Reviews using:⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.SumSearch ⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.TRIP⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.Ovid MEDLINE⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.PubMedFreehttp://www.cochrane.org/docs/CLdbaseinfo.htmPIER (Physician Information Education Resource)American College of Physicians (ACP)ACP Web site if an ACP member. Otherwise, the STAT!Ref search Database from Teton Data Systems can be used.Free to ACP members. Otherwise, must use through an institutional subscription.http://acponline.orgClinical evidenceBritish Medical Journal (BMJ) Publishing GroupBMJ-provided Web sitePay-per-view, one year personal subscription, or institutional subscription.http://clinicalevidence.bmj.comUS National Guideline Clearinghouse (NGC)Agency for Healthcare Research and Quality (AHRQ), U.S. Department of Health and Human Services⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.AHRQ supported Web site⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.PubMed⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.Ovid MEDLINE⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.SumSearch,⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.TRIPFreehttp://www.guideline.gov/ It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources. Open table in a new tab The following list RCTs, cohort studies, case-control studies, and case series/reports (Table 3):1Medline: This is a comprehensive and extensive database of biomedical literature that is updated daily. Currently, it contains more than 16 million references to journal articles, including citations from approximately 5,200 worldwide journals in 37 languages, focused on biomedicine. Created and compiled by the United States National Library of Medicine and the National Institutes of Health, Medline is intricately linked to PubMed, a free interface for searching Medline material. PubMed has more than 19 million citations and links from article references to articles about the same or similar topics, articles that cite the specific reference, and the publishers' versions of electronic full-text copies of articles. Most of these full-text versions are not provided for free by the publishers, however, and clinicians may need to pay for each article. Medline can also be searched using Ovid or Scopus interfaces.2PubMed Clinical Queries: This feature in PubMed allows physicians to search Medline by restricting the search to the type of question the physicians are trying to answer (which they label etiology, diagnosis, therapy, prognosis, and clinical prediction guides). It brings back results that are likely to have direct clinical application based on the type of question identified.3EMBASE: This database contains more than 19 million indexed records from more than 7,000 peer-reviewed journals across all disciplines and areas of health sciences research. However, EMBASE searches across journals and resources that have a focus on drugs and allied health disciplines.4Scopus: This is a large abstract and citation database covering literature in the fields of physical, life, medical, and social sciences from more than 18,000 peer-reviewed journals. More than half of Scopus' content originates internationally, and references go back to 1996. Scopus also searches Web sites, patents, trade publications, and conference papers.Table 3RCTs, Cohort Studies, Case-Control Studies, and Case Series/Reports⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.ResourceVendor/SupplierAvailabilityCostURLMEDLINEU.S. National Library of Medicine and National Institutes of Health⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.PubMed interface to the MEDLINE® database, ⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.Ovid MEDLINE by WoltersKluwer⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.Scopus, an Elsevier productPubMed Gateway is free to use. Individual subscription available for Ovid's interface to Medlinewww.ncbi.nlm.nih.gov/pubmedhttp://www.ovid.comPubMed Clinical QueriesU.S. National Library of Medicine and National Institutes of Health⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.PubMed⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.SumSearch⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.TRIPFreewww.ncbi.nlm.nih.gov/entrez/query/static/clinical.htmlEMBASEElsevier⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.Elsevier's EMBASE site⁎It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources.ScopusNeed to use institution subscriptionhttp://embase.com/ScopusElsevierElsevier's Scopus siteOnly provides institutional licenseshttp://scopus.com It is important to check with the medical library with which the clinician is affiliated with to find out if fee-based resources can be accessed through the library's institutional subscription or license to the above resources. Open table in a new tab The following resources list expert opinion (Table 4):1UpToDate: Many physicians get the information they need by asking colleagues who are considered “experts” in the field, or people with clinical experience in the particular field.14Williamson J.W. German P.S. Weiss R. et al.Health science information management and continuing education of physicians A survey of U.S. primary care practitioners and their opinion leaders.Ann Intern Med. 1989; 110: 151-160Crossref PubMed Scopus (226) Google Scholar, 15Weinberg A.D. Ullian L. Richards W.D. et al.Informal advice- and information-seeking between physicians.J Med Educ. 1981; 56: 174-180PubMed Google Scholar UpToDate (UpToDate Inc, Waltham, MA) is an online version of collegial information. This resource provides synthesized topic reviews written by clinical experts. Each review provides an overview of the condition or topic and offers explicit recommendations. Currently, it covers more than 7,700 topics in 14 different medical specialties including cardiology although not specifically anesthesiology. UpToDate also includes a section on new recommendations and one with information for patients. This type of resource is comparable to an online text book and is very easy to use.16Hoogendam A. Stalenhoef A.F. Robbe P.F. et al.Answers to questions posed during daily patient care are more likely to be answered by UpToDate than PubMed.J Med Internet Res. 2008; 10: e29Crossref PubMed Scopus (64) Google Scholar2eMedicine: This is a peer-reviewed clinical knowledge base from WebMD (WebMD LLC, Atlanta, GA) containing more than 6,500 clinical review articles in 59 medical specialties written by physician contri