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Interactive Cardiovascular and Thoracic Surgery 2 (2003) 405–409 www.icvts.org Protocol - Cardiac general Towards evidence-based medicine in cardiothoracic surgery: best BETS Joel Dunning*, Brian Prendergast, Kevin Mackway-Jones Department of Cardiothoracic Surgery, Manchester Royal Infirmary, Oxford Road, Manchester, M13 9WL, UK Received 14 May 2003; received in revised form 5 August 2003; accepted 26 August 2003 Summary Cardiothoracic surgeons are faced with the dilemma that many clinical qu
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  Protocol - Cardiac general Towards evidence-based medicine in cardiothoracic surgery: best BETS Joel Dunning*, Brian Prendergast, Kevin Mackway-Jones  Department of Cardiothoracic Surgery, Manchester Royal Infirmary, Oxford Road, Manchester, M13 9WL, UK  Received 14 May 2003; received in revised form 5 August 2003; accepted 26 August 2003 Summary Cardiothoracic surgeons are faced with the dilemma that many clinical questions in their daily practice to do not have universally agreedanswers, but patients increasingly demand the ‘best practice’ from their doctors. In addition time pressures mean that clinicians are unable tokeep up with the full spectrum of published research and current resources that collate evidence for clinicians have few if any resources forcardiothoracic surgeons. We have adopted an approach pioneered in emergency medicine, namely the Best Evidence Topic or BestBET.Clinicians select a clinical scenario from their daily practice that highlighted an area of controversy. From this, a three-part question isgenerated and this is used to search Medline for relevant papers. Once the relevant papers are found, these papers are critically appraisedusing validated checklists and the results are summarized. A clinical bottom lineis reached after this process. To add confidence tothe qualityof the search a second author and then an Evidence Based Journal Club checks the BET to ensure that no relevant evidence is missed. TheseBETs will then be posted on the ICVTS website prior to publication for widespread commentary. The resulting BETs, written by practisingcardiothoracic surgeons, will then provide robust evidence-based answers to important clinical questions asked during our daily practice. q 2003 Elsevier B.V. All rights reserved. Keywords: Evidence based medicine; Classification; Cardiac surgical procedures; Thoracic surgery 1. Introduction In order to achieve the optimal care for patientsundergoing cardiac and thoracic operations it is essentialthat their management is based upon the best availableevidence. However, although coronary bypass grafting isthe most studied operation in the world[1], a formalizedapproach to evidence-based practice in cardiothoracicsurgery is lacking. While other hospital and communityspecialties benefit from many resources that collate andsummarize the available evidence[2–5], these resources arenotable for the absence of data on surgical research and inparticular cardiothoracic surgical research. While someorganizations present guidelines on some aspects of ourspecialty[1],we lack a peer-reviewed resource of topics in cardiothoracic surgery that is created, reviewed and utilizedby members of our own specialty, that can lead to bestpractice in cardiac and thoracic surgery.The particular problem facing surgical specialties is thatthe evidence that does exist is frequently not of the highestquality and therefore most formal critical appraisalprocesses tend to discard the majority of our papers due tomethodological flaws or poor design by their standards.In 1998, emergency medicine faced a very similarproblem in that many clinical questions in this specialtycould not be answered by high-quality studies, but thatanswers became apparent when the ‘best available’evidence was reviewed. The process was formalized by aprocess of creating Best Evidence Topics (BestBETs).BestBETs were first described by the EmergencyDepartment at the Manchester Royal Infirmary[6]. Theywere developed as an educational tool to focus teaching of competencies in the practice of evidence-based medicine to junior doctors[7], but soon developed into a means of identifying the need for evidence-based changes in practiceand of helping to effect these changes. BestBETs have sincebeen published regularly in peer-reviewed journals (cur-rently the Emergency Medicine Journal [8]and then the  Archives of Disease in Childhood  [9]), and are now listedand updated on a dedicated website[10]. This website(http://www.bestbets.org) has been enthusiasticallyreviewed both nationally[11]and internationally[12],and is recognized as a major resource for evidence-basedpractice[13]. 1569-9293/$ - see front matter q 2003 Elsevier B.V. All rights reserved.doi:10.1016/S1569-9293(03)00191-9Interactive Cardiovascular and Thoracic Surgery 2 (2003) 405–409www.icvts.org*Corresponding author. Tel.: þ 44-161-276-6984; fax: þ 44-161-276-8538. E-mail address: joeldunning@doctors.org.uk (J. Dunning).  Therefore, realizing that many clinical questions couldbe answered in this way in cardiothoracic surgery, we set upan Evidence Based Journal Club in Cardiac Surgery. Weaimed to answer clinically relevant questions generatedduring our daily practice, by using the best availableevidence to create best-evidence topic reports in cardio-thoracic surgery. 2. Design BETS are constructed in five stages, based on theprinciplesunderlyingallevidence-basedmedicine(Table1). 2.1. Asking the right questions BETs are generated as a result of clinical questions thatface busy cardiac surgeons in their daily practice. Thus asthe first step, a clinical scenario is presented that clearlyillustrates the topic of interest which is familiar to the personpreparing the report. This ensures that each topic is rooted inclinical practice and will be of immediate use to clinicians.In order to ensure that the question is well defined andanswerable, this clinical question is then summarized as athree-part question (Table 2).The three-part question is the cornerstone of allevidence-based search strategies as it both concisely definesthe question to be answered, and it leads the search strategyfrom the available literature databases[14]. An example of these first two steps is given inTable 3. 2.2. Searching for the evidence A key component of the Best Evidence Topic is that allthe ‘best available’ evidence is reviewed, as only then canstrong conclusions be drawn about the particular topic. Amajor strength of BETs is that they are not exhaustivesystematic reviews and thus rather than taking months toperform, they take on average 5 hours to complete[15],meaning that they are easy to perform by practisingclinicians.It must be realized, however,that no attempts are made tosearch the grey literature, unpublished literature or tostatistically aggregate the data, and thus what is offered byBETs are practical answers to clinical questions byclinicians, rather than long reviews and summaries of thefull body of research on that topic. 2.3. Medline search Medline is a register of over 6 million abstracts from1966 onward, compiled by the National Library of Medicineof the United States. There are several software packagesthat can be used to search Medline including the freeservice, PubMed and the subscriber service, Ovid[16,17].In order to achieve the aims of the BET, which is to findand summarize the best evidence, it is important that thesearch strategy has a high sensitivity (meaning that it has thehighest likelihood of retrieving all relevant papers). In orderto achieve this, the search is done in stages. Each section of the three-part question is taken individually, and as manyterms as possible are combined using the Boolean operator‘OR’ to find all abstracts that contain information on thatarea. You now have a search for each section of the three-part question. These three sections are then combined usingthe Boolean operator ‘AND’ to find papers that containinformation on all three areas of your question. This is awell-recognized method for performing sensitive searchesand has been described in detail in the British Medical Journal [18].We aim to find around 50–200 abstracts that we can thenhand-search for relevance. However, two problems com-monly occur during searching: either too many abstracts arefound or too few are found. If too few abstracts are found weneed to increase the sensitivity of our search. This may bedone by using more terms in the search including pluralversions and alternative spellings and by using the ‘explode’function for Medical Subject Headings (MeSH) to includefamilies of terms that all fall under a single MeSH heading.If too many abstracts are found, our search is not specificenough (low proportion of abstracts found are relevant).Care must be taken when increasing the specificity not toeliminate abstracts which would be potentially useful. Table 1The 5 stages of constructing a BET1. Asking the right question2. Searching for the evidence3. Appraising the evidence4. Summarizing the evidence5. Reviewing the evidenceTable 2Generation of a three-part question1. Patient characteristic or patient group2. Intervention(s) or defining question3. Relevant outcome(s)Table 3Examples of scenario and question Clinical scenario You are about to perform a CABG on a 70-year-old lady who has left mainstem disease and an ejection fraction of 30% on echocardiography. She wasan urgent referral from the cardiologists after being admitted 3 weeks agowith unstable angina, but has been stable since admission. You wonderwhether preoperatively inserting an intra-aortic balloon pump would be of benefit to her? Three-part question In [High-risk patients undergoing coronary arterial surgery]Does [Prophylactic IABP insertion]Improve [In-patient survival, or time to discharge]  J. Dunning et al. / Interactive Cardiovascular and Thoracic Surgery 2 (2003) 405–409 406  While search terms can be removed, it is often better to useother techniques such as the LIMIT command, limiting tohuman studies, or to use a methodological filter to look onlyfor high-quality studies[3,6]. Often the search may need tobe done a few times, and the three-part question may need tobe changed for the purposes of the search strategy, as oftensearching for ‘survival or outcome’ may result in a poorspecificity, in comparison to searching for a second keycomponent of the intervention (seeTable 4). The abstractsfound in our example search are shown inFig. 1. 2.4. Consider other sources of evidence The Medline search should form the basis of the BET,but if the results are poor from this search, an author mayconsider searching other resources. These may includeEMBASE, the European equivalent of Medline, witharound 4 million abstracts from 1974, including manyabstracts not included on Medline, or other databasesalready mentioned above including the Cochrane Databaseof systematic reviews[2–5].These additional resources are usually only necessary if no relevant papers have beenfound on Medline, as additional searches help to assurereaders that there really were no papers that could answerthe clinical question. 2.5. Scanning titles and abstracts Once a satisfactory number of abstracts have been found,the titles and abstracts now need to be scanned, as themajority of abstracts will not be relevant to the clinicalquestion. From a search that finds 50–200 abstracts it isusual to find only 5–10 papers that require critical appraisalfrom the full text article. This scanning process is, however,quite quick and therefore we recommend that it is better toscan a larger number of abstracts rather than risk missingrelevant papers by over refining the search. 2.6. Appraising the evidence The papers found by the search strategy are nowrequested and appraised. The appraisal of each paper isperformed in a structured format, using critical appraisalchecklists. These are widely available in several formats,and these aid in assessing the paper for methodological andanalytical soundness and help uncover any significantmethodological flaws[19–21]. In addition, after appraisal,the paper can be categorized in terms of the type of studyand the level of evidence presented[3].Generally, in constructing the BET we are interested in the papers of thehighest level only. Thus if some papers are level I evidencethen there is no need to consider papers of level II or IIIevidence in the final BET. In contrast, if there are severallevel III papers but no papers better than this, then these willall be considered. The levels of evidence are presented inTable 5,and enable readers of the BET to come to aconclusion about the certainty to which evidence exists toanswer the question. 2.7. Summarizing the evidence A search has now been performed, relevant papersidentified and reviewed, and we are now in a position to Table 5Levels of evidenceI Strong evidence from at least one published systematic review of multiple well-designed randomized controlled trialsII Strong evidence from at least one published properly designedrandomized controlled trial of appropriate size and in anappropriate clinical settingIII Evidence from published well-designed trials without randomization,single group pre-post, cohort, time series, or matched case-controlstudiesIV Evidence from well-designed non-experimental studies from morethan one centre or research groupV Opinion of respected authorities, based on clinical evidence,descriptive studies or reports of expert consensus committeesTable 4Search strategy using Medline 1966 to December 2002 using the OVIDinterface[exp Coronary Artery Bypass/ OR CABG.mp OR exp Thoracic surgery/ OR Coronary art$ bypass.mp OR cardiopulmonary bypass.mp OR expCardiovascular surgical procedures/ OR exp Thoracic surgical procedures/]AND[exp Intra-aortic balloon pumping/ OR intra-aortic balloon pump.mp ORIABP.mp]AND[exp preoperative care/ OR pre-operative.mp]Note that for this search the third section of the three-part questionrelating to survival or hospital outcome performed very poorly in terms of specificity,givingverylarge numbersof abstractsandthusit wasdecidedtosearch for terms relating to preoperative care instead. / indicates a MeSH heading, exp indicates explode (applicable only toMeSH headings),.mp is main point search (title, abstract,and MeSH terms).Fig. 1. Number of abstracts found from final search strategy.  J. Dunning et al. / Interactive Cardiovascular and Thoracic Surgery 2 (2003) 405–409 407  summarize the evidence and answer our srcinal question.The summary follows a structured format in order to ensuretransparency in the process for other clinicians reading theBET. The first of our BETs in Cardiac Surgery are publishedin this Journal. The full process which we have just beenthrough to create the BET is described in full. This includesthe title, the clinical scenario, the derived three-partquestion, the detailed search strategy, and the results of the search. The number of abstracts found is explicitlystated, with the number of papers deemed to be irrelevant orof poor quality. The relevant papers are then summarized ina table, under headings including the author, date andcountry of research, the patient group, the study type (andlevel of evidence), the outcomes investigated, the keyresults and any identified study weaknesses or comments.Below the table a comments section is then used tosummarize the findings of the papers and to discuss anyissues arising from the critical appraisal of the papers. Thissection can also be used to highlight the need for furtherresearch. Finally, a clinical bottom line is given to answerthe srcinal question of the BET. 2.8. Reviewing the evidence The BET is now complete, and by following a well-structured format it is hoped that the BET is comprehensiveand the conclusions are valid. However, there are severalfurther steps that ensure that clinicians worldwide readingBETs in this journal can be convinced that great rigour hasbeen used in its construction (summarized inTable 6). 2.9. Checking author  A second author is asked to fully review the BET. Thisinvolves returning to Medline and re-running the search,and adding new terms or changing terms in the searchstrategy in an effort to find additional papers of relevance.The second author must also look through all the ‘hits’ fromthe search to ensure that no relevant papers were missed.Finally, the second author reviews all the critical appraisalsof the relevant papers, and checks the reference lists of allpapers to ensure that conclusions drawn in the BET are justified and that no relevant papers have been missed. 2.10. Evidence Based Journal Club An Evidenced Based Journal Club in CardiothoracicSurgery has been set up in a similar fashion to the well-established Journal Club that reviews BETs in EmergencyMedicine[7]. This consists of a weekly meeting of 10–15consultants and trainees in cardiothoracic surgery who havenow been given training and experience with BETs andcritical appraisal. Each BET is reviewed at this forum. Inparticular this expert group is asked whether they know of any additional papers that may have been missed or of anyadditional search terms that could have been used toimprove the sensitivity of the search. 2.11. Web-based review on the ICVTS website The unique nature of  Interactive Cardiovascular and Thoracic Surgery means that BETs can be published on thewebsite for widespread review prior to publication. Thisopportunity allows for widespread appraisal of the contentof each Best Evidence Topic. Clinicians enteringhttp:// www.ICVTS.orgwill be able to browse the full BET priorto publication, and in addition will be able to see additionalinformation on the critical appraisal process, the checklistsand levels of evidence used in the process and other BestEvidence Topics onhttp://www.bestbets.org. Only after thisprocess which is unique to ICVTS will the BET bepublished. 2.12. Regular review of the BETs Best Evidence topics are a review of the literature at apoint in time. However, all Cardiac BETs published in theICVTS will be given a ‘shelf-life’, after which the searchstrategy will be reviewed and re-run. Any additional papersthat are relevant can then be reassessed and the BETupdated on the website. It is envisaged that this would occurevery 3–5 years for each BET. 3. Discussion BETs are an attempt to promote evidence-basedcardiothoracic surgery for busy clinicians by providingclear answers to relevant clinical questions. They are alsointended to not only to be read by clinicians but to beperformed and reviewed by clinicians that face difficultclinical questions on a daily basis.Best BETs has transformed emergency medicine into anevidence-based specialty, with over 200 BETs alreadypublished in the Emergency Medical Journal, and 600BETS registered onhttp://www.bestbets.orgfrom authorsworldwide. In addition, other specialties are beginning touse this highly successful format, and BETs in Paediatricshave now been published regularly in Archives of Disease inChildhood  for the last 2 years.Other bodies exist that do review the evidence behindsome aspects of cardiac surgery. The American HeartAssociation Task Force on Practice Guidelines presentsevidence about several areas of Cardiac Surgical Care[1].However,cliniciansworldwidecannotgetinvolvedinasking Table 6Further steps1. Second author to check the search strategy and output2. Discussion of search by members of the Evidence Based Journal Club3. Web-based review on ICVTS website4. Regular revision of search strategy by web-editors  J. Dunning et al. / Interactive Cardiovascular and Thoracic Surgery 2 (2003) 405–409 408
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