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Surgical Technology: Evidence Based Research

Evidence Based Practice Defined

Research Inside the Context of Caring: What is Evidence Based Practice?

Evidence Based Practice is a problem solving approach to the delivery of healthcare that integrates the best empirical evidence from well-designed research studies and patient care data, and combines it with patients expressed preferences and values, and professional expertise (including consideration of care setting and available resources)

Evidence-Based Practice: Step by Step: Igniting a Spirit of Inquiry.

Melnyk, Bernadette; Mazurek PhD, RN; PMHNP, FNAP; Fineout-Overholt, Ellen; PhD, RN;  FNAP, FAAN; Stillwell, Susan; DNP, RN; Williamson, Kathleen; PhD, RN

AJN, American Journal of Nursing. 109(11):49-52, November 2009.

DOI: 10.1097/01.NAJ.0000363354.53883.58

Evidence Based Research

Why Conduct Evidence Based Research?

Healthcare professionals conduct Evidence Based Research to support Evidence Based Practice because they want the best outcomes for their patients. 

The Goal = best outcomes for the patient, highest quality of care
The Focus = finding evidence of the best methods, interventions and practices
The Evidence = found in the most current professional research literature and clinical practice guidelines

Critical Appraisal

Critical Appraisal: Evaluating the Evidence Provided in Research Studies

What is our process for selecting high quality information to apply in practice?

As you review the research studies from your results - you want to ascertain:

  1. What is the level of evidence? How strong is the evidence offered by each research study / article. See "Evidence Hierarchy Pyramid"
  2. How well was the study conducted? Look at internal validity to determine was the study free from bias and error. See "Appraisal Questions" from Concepts of Evidence Based Practice for the Physical Therapist Assistant

The level of evidence plus internal validity are a proxy for quality and give clinicians confidence to apply evidence in practice.

Finally, consider external validity - how applicable and relevant is the information to the question at hand -- is it really relevant to your clinical issue and will you be able to apply it to professional practice?

Evidence Hierarchy Pyramid

The Evidence Hierarchy Pyramid Is Used To Graphically Represent the Quality of Medical and Health Science Research

The higher on the pyramid, the more comprehensive in scope is the research study, the more rigorous is the methodology conducted and the peer review.

Evidence Hierarchy Pyramid

Research Study Designs

Glossary of Terms for Research Study Designs

Meta-Analysis: A meta-analysis is a review that combines the quantitative (numbers) results from different studies on a defined intervention in order to obtain a quantitative estimate of the overall effect of the particular intervention.  A meta-analysis produces a stronger conclusion than can be provided by any individual study.

Systematic Review: A systematic review tries to identify, appraise, select and synthesize all RCTs (randomized control trials) relevant to a specific clinical question.  Stringent guidelines are set in order to draw a conclusion about whether or not there is conclusive evidence about a specfic treatment or topic.

Randomized Control Trial: An RCT is a clinical trial in which the subjects are randomly distributed into groups that are either subjected to the experimental procedure (such as use of a certain rehabilitative treatment) or that serve as controls.  It is the research design considered to provide the most reliable evidence for evaluating the effectiveness of an intervention. See Randomization 

Randomization - used in RCTs: Randomization (or random allocation) is a method like tossing a coin to assign patients to treatment groups (the experimental treatment is given if the coin lands on "heads"; and a conventional, "control" or "placebo", treatment is given if the coin lands on "tails").

Cohort Study: A study designed to determine the relationship between a condition and a characteristic shared by some members of a group. The population selected is healthy at the beginning of the study. Some of the members of the group share a particular characteristic, such as cigarette smoking. The researcher follows the population group over a period of time, noting the rate at which a condition, such as lung cancer, occurs in the smokers and in the nonsmokers.

Retrospective or Case Control Study: A study where previously existing incidents of a medical condition are used in lieu of gathering new information. A group of patients with a particular disease or disorder, such as myocardial infarction, is compared with a control group of persons who have not had that medical problem. The two groups, matched for age, sex, and other personal data, are examined to determine which possible factor (e.g., cigarette smoking, coffee drinking) may account for the increased disease incidence in the case group.

Case Series: A report on a series of patients with an outcome of interest. No control group is involved.

Descriptive or Qualitative Study: A descriptive study is one in which information is collected without changing the environment (i.e. nothing is manipulated, no experiment is occurring). Sometimes these are referred to as correlational or observational studies. A descriptive study can provide information about the naturally occurring health status, behavior, attitudes or other characteristics of a particular group. Descriptive studies can involve a one-time interaction with groups of people (cross-sectional study) or a study might follow individuals over time (longitudinal study). These types of studies are often done before an experiment to know what specific things to manipulate and include in an experiment.

Acquiring the Evidence - Research Studies

Finding Research Studies Published in Professional Journals

CINAHL and PubMed are great subject specific databases to use to find research studies in professional journals. See the "Finding Articles" page on this guide for access. The CINAHL database contains nursing and allied health literature and PubMed contains medical and life science literature so these two databases complement each others content and provide appropriate overlap for your research.

Effective Search Strategies:

  1. Develop search statements that define your Population, Intervention or Issue of Interest, and Outcome of Interest

  2. Use CINAHL Headings or MESH Headings to identify preferred terminology in the database

  3. Use the Advanced Search with the AND connector to combine searches

Practice Guidelines

Practice Guidelines - Another Important Resource for Evidence Based Research

Practice Guidelines are concise statements designed to help clinicians and patients make decisions about appropriate healthcare for a specific clinical circumstance. Practice Guidelines are developed based on the research findings from meta-analyses, systematic reviews and RCTs and use clinical examples to demonstrate how to integrate these research findings into practice.