Introduction to Evidence Based Practice What is 循证实践介绍什么是.doc

Introduction to Evidence Based PracticeWhat is evidence based practice?Evidence based practice is essentially concerned with making appropriate and safe clinical decisions based on sound evidence. There are many definitions within the literature and different terminology is often used: evidence based medicine; evidence based healthcare and evidence based practice. Throughout this module, we will refer to evidence based practice. Essentially its about evidence based decisions-making. Rosenberg and Donald (1995) defined EBM as .process of systematically finding, appraising and using contemporaneous research findings as the basis for clinical decisions.Sackett et al (1996) defined evidence based medicine asthe conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.Both of these definitions points towards research or empirical evidence and leaves little room for clinical experience or patient preference. Sackett et al (2000) later revisited this definition and re-defined evidence based medicine egrating best research evidence (external evidence) with clinical expertise and patient valuesIts about using the most up to date research to guide the clinical healthcare decisions we make in collaboration with our patients in order to follow the most appropriate management plan. So what exactly is clinical expertise? Sackett et al (1996) defined clinical expertise as: proficiency and judgment acquired though practice experience; the use of increasingly effective and efficient diagnosis; compassionate and thoughtfulness of an individuals circumstances, rights and preferences in making choices in health care.They go further to describe external evidence as clinically relevant research, whether patient centred or fundamental science- quantitative and qualitative-depending on the nature of the question to be answered; research investigating the accuracy and reliability of diagnostic tests, the power of prognostic markers, the efficacy and safety of therapeutic, rehabilitative and preventative treatments.In this context of clinical expertise and best external evidence, is it not about integrating science and art. Carper (1978) described ways of knowing in nursing. She identified science and art, with science being involved with objective measurement and art being concerned with clinical proficiency and judgment-clinical expertise and external evidence?Evidence based practice is most certainly not about using research to dictate treatments or healthcare decisions. Although there is security in numbers (as with randomised controlled trials), health care practitioners must also consider individual circumstances and choices when deciding the most appropriate action plan. Although it is important to put this into perspective, as we must have new evidence and research as without this, everyday practice becomes out of date and unsafe for all those involved.Why do we need EBP?In 1972, Archie Cochrane and influential British Epidemiologist identified that there was a lack of systematic review of evidence in health care decision-making. In 1979, he statedit is surely a great criticism of our profession that we have not organised a critical summary, by speciality or sub-speciality, adapted periodically, of all relevant randomised controlled trials.The work that Cochrane started has continued through the Cochrane Collaboration. The collaboration publishes systematic reviews of RCTs in the Cochrane Database of Systematic Reviews.Rosenberg and Donald (1995) recognise that EBP attracts support and criticism. They also identify that EBP is difficult to evaluate as it usually involves a problem solving approach in which a question is set and one attempts to answer the question through a series of steps. The authors also identify that it is by the act of critical appraisal that individuals may learn what is good research methodology and that this may help practitioners to be better equipped to carry out the research of the future. They also recognise that this is difficult to quantify- how does one measure that as a result of learning critical appraisal skills, one produces better research or is indeed better equipped?There is however growing evidence that EBP is beneficial. In 1993, Shin et al undertook research which showed that graduates from traditional medical schools gradually declined in knowledge relating to clinical practice decisions, whereas graduates from schools which teach evidence based medicine and self-directed learning are up to date as long as fifteen years after graduating. Greenhalgh (1997) also evaluated an EBP workshop that was run in London and identified benefits such as new skill acquisition (searching PubMed), altered attitudes to multidisciplinary learning and exposure to new educational techniques such as role-play and problem based learning.Advantages of an evidence based approach to clinical decision-making. Rosenberg and Donald (1995) identify the following advantages: Synthesises education with clinical practice With an understanding of EBP comes an ability to ask precise questions and know how and where to find the answers EBP has the potential to improve continuity and uniformity of care by way of common approaches and guidelines Provides a common framework for those involved in problem solving clinical decisions, such as purchasers, clinicians and patients Enables individuals to develop a system of regularly and routinely updating their own knowledge base Improves understanding of research methodology and provides a framework for critical appraisal of this methodology Improves computer literacy and search techniques Improves reading habits by allowing one to understand the appropriateness of the methodology and quickly find the most relevant findings Encourages better communication with patients about rationales behind management decisionsAlongside the advantages, there are also disadvantages EBP takes time to both learn and continue with. The infrastructure costs money-computer hardware and software, although most NHS Trusts have access to National Databases for staff. The question is whilst undertaking clinical care, when a question arises, do health care practitioners have the time to access the databases to search for evidence which may inform their decision-making? Some consider a negative the fact that EBP often identifies that more research needs to be done. Whilst this may offer potential researchers new ideas, it may mean that evidence does not exist from which clinical decisions can be made. Practitioners may also fear losing face for not being up to date with the latest technique and some may fear that purchasers and managers could misunderstand the evidence and misuse it in order to simply cut costs (Rosenberg and Donald, 1995).Process in PracticePorzsolt et al (2003) describes six steps to evidence based decision-making which are outlined in Table 1.StepAction1Transformation of a clinical problem into 3 or 4 part question2Answer to question based on internal evidence only or professional experience3Finding external evidence to answer the question4Critical appraisal of external evidence5Integrating internal and external evidence6Evaluation of decision-making processTable 1. 6 steps to evidence based decision-makingPorzsolt et al (2003). Evidence based decision-making.EBM. 8: 165-166.Essentially, the process involves setting the question, finding the evidence, appraising the evidence and acting on the evidence. Setting the QuestionThe next session in the module will help you to understand how to formulate a searchable question in more detail but the most common framework for setting a question is the P.I.C.O principle. Population Intervention Comparison/control OutcomeThe first thing to say is that not all clinical questions will have a comparison and this will be explored in more detail in the next session.By using the P.I.C.O approach to a clinical question, one can break the problem down into chunks or components to form an answerable question. Consider the example of that a 65 year old lady comes to your surgery with chronic renal failure (CKD stage 5). Her blood pressure is raised 145/90 and she is currently taking an antihypertensive. When questioned she tells you that she eats a lot of salt and wonders whether she should cut down after watching the BBC news this morning. To turn this into an answerable question, one can use the P.I.C.O principle as follows:Population= hypertensive patients with CKD stage 5Intervention= low sodium dietComparison= regular diet/no salt reductionOutcome= reduction in blood pressureThe question becomes: In hypertensive patients with CKD stage 5, does a low sodium diet have an effect on blood pressure?Finding the evidenceIn order to find the most relevant research to answer your question, one must consider the types of studies you will be looking for. There is a well established hierarchy of evidence but one must exercise caution, as it does not include weaker designs or qualitative studies. If your question related to the effect of aromatherapy on pregnant womens well being in the third trimester, then it is unlikely that one would find any RCTs on this subject. But beware. hierarchies are not evidence based but rather have been developed following consensus of the experts, or the opinions of a few. The hierarchy of evidence is outlined in Table 2.Strength of EvidenceType of study designISystematic reviews and meta-analysesIIWell designed randomised trialsIIIWell designed trials without randomisation (single group pre and post cohort; time series; matched case-controlled studies)IVWell designed non-experimental studies from more than one centreVOpinions form respected authorities based on clinical evidence, descriptive studies or reports of expert committeesTable 2. Hierarchies of EvidenceGreenhalgh, 1997One needs to also consider where to start searching for this evidence. There are well recognised databases such as PubMed; the Cochrane Library; EMBASE; Cinahl; the National Research Register; Health Technology Assessment Database (HTA); NHS Economic Evaluation Database; Database of Abstracts of Reviews of Effectiveness (DARE). All of these databases are available for you to search on StudyNet through the learning Resource section and this module will allow you to develop rigorous searches on the most relevant databases.Appraising the EvidenceIs the evidence that youve located through your searches valid and clinically useful? Critically appraising the research is the next process and it is simply asking a few key questions about the validity of the evidence and its replace to a patient or group of patients. As Glasziou et al (2007) point out, critical appraisal is about asking if the study question is the same as your own question, considering how well the study was done and finally asking what the results mean. There are a number of published tools available for critical appraisal and again throughout the module, you will be using these to evaluate various research papers. Some examples include the CASP (Critical Appraisal Skills for Practitioners) tool; Duffys Critical Appraisal checklist and Greenhalghs tools from How to Read a Paper (Greenhalgh, 1997). Essentially one must ask whether the research carried out has been carried out in a methodologically sound or un-biased way. If it hasnt then one must question the validity of the results. The questions one must ask are: How were the subjects selected-randomly and was the sample size large enough? How were the subjects allocated to groups- blind allocation? Were the groups managed in the same way throughout the course of the study? How were the outcomes measured- were the assessors blinded?Acting on the EvidenceOnce you have appraised the relevant evidence and concluded the results from the methodologically sound papers and thought about how you have answered your question, one must consider how to apply the evidence to your clinical situation, taking into account your own clinical expertise or experience and the patients preferences or values. Galsziou et al (2007) recommend asking yourself the following questions:1. Is the intervention feasible in this setting?2. What else do I need to apply this evidence?3. What alternatives are available?4. Is my patient so different from those in the study that the results do not apply at all?5. Will the potential benefits of the intervention outweigh the potential harm?6. What does my patient think about this?One must also consider whether one should act on the evidence immediately- is the weight of the evidence so strong that practice needs to respond and change immediately? Does one need to develop protocols or guidelines for staff? How will the information learned be disseminated?In conclusion, this paper has provided an introduction to evidence based practice, provides some definitions, put forward some of the advantages and disadvantages of EBP and given a brief introduction to the process in action. Much of what has been presented here will be discussed over the coming module in more detail.When utilising EBP, practitioners need to give due weight to evidence and sources of evidence. Assessment of this evidence needs to be more flexible than just a hierarchy of evidence. It is vital for practitioners to be able to define questions, find the relevant literature, appraise the research and incorporate the evidence into their decision-making for patient care. ReferencesCarper, B.