What is evidence- based medicine (EBM)?
It is widely accepted as ‘the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients’.
Individual clinical expertise does matter. However, it is largely modified by the institutional limitations with regard to infrastructure, or lag or lack of updated protocols. Apart from a good number of teaching institutions, most of the practicing hospitals will not provide facilities or opportunities for scientific follow-up to validate the current clinical practice. Most of the times, cost-factor will also play an important role while deciding in favor of a new drug or monitoring technique in anesthesia.
As doctors, we should be always aiming to improve patient outcomes whilst continually updating practice as new research becomes available. Here, the focus is definitely on the patient-care. However, it should be the anesthesiologist who should apprise the patient and the surgical team of the evidence-based updates.
There are enough online resources to help out in advanced literature search. Though some of the resources are accessible only to the subscribers, many databases allow free access. Apart from Google, the popular search engine, Google scholar also can narrow down your search to scientific resources and enable filters like articles published after 2016, 2019 etc.
Three free, publicly available databases may be of use. The first is the Cochrane Library, which publishes systematic reviews prepared by the Cochrane Collaboration. Secondly, the ‘Database of Abstracts of Reviews of Effects' (DARE) evaluates the effects of healthcare interventions, health service organization, and delivery. DARE contains over 15 000 abstracts of quality-assessed reviews, as well as all Cochrane reviews and protocols, so will yield even more resources. The third is PROSPERO, an international database of prospectively registered systematic reviews. It aims to provide a centralized resource in which proposed systematic reviews can be collated, thus avoiding duplication. Completed systematic reviews have their key findings recorded and compared against their aims at registration.
Levels of Evidence
The levels of evidence are an important component of EBM. Understanding the levels and why they are assigned to publications and abstracts helps the reader to prioritize information. A large number of hierarchies of evidence have been proposed. They used to rank the relative strength of results obtained from scientific research.
The highest ‘level of evidence’ should be sought to answer the clinical question posed; if such evidence is sparse, or low quality, it is often necessary to resort to lower levels.Typically, systematic reviews of completed, high-quality randomized controlled trials (RCTs) – such as those published by the Cochrane Collaboration – rank as the highest quality of evidence above observational studies, while expert opinion and anecdotal experience are at the bottom level of evidence quality.
Three checklists have been developed to guide authors of three types of article, but these can also help readers make sense of them. These are There is also the ‘Enhancing the QUAlity and Transparency Of health Research (EQUATOR)’ network, which exists to improve the quality of health research reporting.
– Consolidating Standard of Reporting Trials (CONSORT)
– Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)
– STrengthening the Reporting of OBservational studies in Epidemiology (STROBE)
Statistics is central to evidence-based medicine.However, the interpretation of what is termed as 'statistically significant' may not be clinically significant. For example, say, a study comparing efficacies of two anti-emetic drugs, one of them reduces the postoperative nausea -vomiting incidence by 2% (from 56% to 54%). It is debatable if this translates into clinically significant finding.The interpretation of P-value and confidence interval also can impact aligning the research data in the context of evidence-based medicine.
Implementing Evidence-Based Medicine
The potential benefits of guidelines are only as good as the quality of the guidelines themselves. Appropriate methodologies and rigorous strategies in the guideline development process are important for the successful implementation of the resulting recommendations The Appraisal of Guidelines for REsearch & Evaluation (AGREE) Instrument was developed to address the issue of variability in guideline quality. To that end, the AGREE instrument is a tool that assesses the methodological rigour and transparency in which a guideline is developed. The latest version AGREE II is available online.
In the post-graduate curriculum, journal club should train the upcoming clinical practitioners in critical appraisal of the research data.
The American Society of Anesthesiologists (ASA) has promulgated guidelines based on the best available knowledge incorporated with the opinions of acknowledged experts for many years.Evidence-based approaches to care integrate individual expertise with data from externally conducted systematic research.
Summary
EBM addresses the deficiencies in clinical care that rely on expert opinion based on physiological reasoning and unstructured use of evidence and provides in its place a coherent framework for assessing and applying the best available evidence to clinical care decisions.
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