DQ#2
TaniAlexis
RESOURCES2A.docxEVIDENCE-BASED PRACTICE IN NURSING
Before describing procedures relating to EBP in nursing, we briefly
discuss some important issues, including the nature of “evidence” and
challenges to pursuing EBP, and resources available to address some of
those challenges.
Types of Evidence and Evidence Hierarchies
There is no consensus about the definition of evidence nor about what
constitutes usable evidence for EBP, but most commentators agree that
findings from rigorous research are paramount. Debate continues,
however, about what constitutes rigorous research and what qualifies as
best evidence.
At the outset of the EBP movement, there was a strong bias toward
reliance on information from studies called randomized controlled trials
(RCTs). This bias stemmed from the fact that the Cochrane Collaboration
initially focused on the effectiveness of therapies rather on other types of
health care questions. RCTs are, in fact, very well suited for drawing
conclusions about the effects of health care interventions (Chapter 9). The
bias in ranking sources of evidence in terms of questions about effective
treatments led to some resistance to EBP by nurses who felt that evidence
from qualitative and non-RCT studies would be ignored.
Positions about the contribution of various types of evidence are less
rigid than previously. Nevertheless, many published evidence hierarchies
rank evidence sources according to the strength of the evidence they
provide, and in most cases, RCTs are near the top of these hierarchies. We
offer a modified evidence hierarchy that looks similar to others, but ours
illustrates that the ranking of evidence-producing strategies depends on the
type of question being asked.
Figure 2.1 shows that systematic reviews are at the pinnacle of the
hierarchy (Level I), regardless of the type of question, because the
strongest evidence comes from careful syntheses of multiple studies. The
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next highest level (Level II) depends on the nature of inquiry. For Therapy
questions regarding the efficacy of an intervention (What works best for
improving health outcomes?), individual RCTs constitute Level II
evidence (systematic reviews of multiple RCTs are Level I). Going down
the “rungs” of the evidence hierarchy for Therapy questions results in less
reliable evidence—for example, Level III evidence comes from a type of
study called quasi-experimental. In-depth qualitative studies are near the
bottom, in terms of evidence regarding intervention effectiveness. (Terms
in Figure 2.1 will be discussed in later chapters.)
For a Prognosis question, by contrast, Level II evidence comes from a
single prospective cohort study, and Level III is from a type of study called
case control (Level I evidence is from a systematic review of cohort
studies). Thus, contrary to what is often implied in discussions of evidence
hierarchies, there really are multiple hierarchies. If one is interested in best
evidence for questions about Meaning, an RCT would be a poor source of
evidence, for example. We have tried to portray the notion of multiple
hierarchies in Figure 2.1, with information on the right indicating the type
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of individual study that would offer the best evidence (Level II) for
different questions. In all cases, appropriate systematic reviews are at the
pinnacle. Information about different hierarchies for different types of
cause-probing questions is addressed in Chapter 9.
Of course, within any level in an evidence hierarchy, evidence quality
can vary considerably. For example, an individual RCT could be well
designed, yielding strong Level II evidence for Therapy questions, or it
could be so flawed that the evidence would be weak.
Thus, in nursing, best evidence refers to research findings that are
methodologically appropriate, rigorous, and clinically relevant for
answering persistent questions—questions not only about the efficacy,
safety, and cost-effectiveness of nursing interventions but also about the
reliability of nursing assessment tests, the causes and consequences of
health problems, and the meaning and nature of patients’ experiences.
Confidence in the evidence is enhanced when the research methods are
compelling, when there have been multiple confirmatory studies, and
when the evidence has been carefully evaluated and synthesized.
Of course, there continue to be clinical practice questions for which
there is relatively little research evidence. In such situations, nursing
practice must rely on other sources—for example, pathophysiologic data,
chart review, quality improvement data, and clinical expertise. As Sackett
and colleagues (2000) have noted, one benefit of the EBP movement is
that a new research agenda can emerge when clinical questions arise for
which there is no satisfactory evidence.
Evidence-Based Practice Challenges
Nurses have completed many studies about the use of research in practice,
including research on barriers to EBP. Studies on EBP barriers, conducted
in several countries, have yielded similar results about constraints on
clinical nurses. Most barriers fall into one of three categories: (1) quality
and nature of the research, (2) characteristics of nurses, and (3)
organizational factors.
With regard to the research, one problem is the limited availability of
high-quality research evidence for some practice areas. There remains an
ongoing need for research that directly addresses pressing clinical
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problems, for replication of studies in a range of settings, and for greater
collaboration between researchers and clinicians. Another issue is that
nurse researchers need to improve their ability to communicate evidence,
and the clinical implications of evidence, to practicing nurses.
Nurses’ attitudes and education are also potential barriers to EBP.
Studies have found that some nurses do not value or know much about
research, and others simply resist change. Fortunately, many nurses do
value research and want to be involved in research-related activities.
Nevertheless, many nurses do not know how to access research evidence
and do not possess the skills to critically evaluate research findings—and
even those who do may not know how to effectively incorporate research
evidence into clinical decision making. Among nurses in non-Englishspeaking
countries, another impediment is that most research evidence is
reported in English.
Finally, many of the challenges to using research in practice are
organizational. “Unit culture” can undermine research use, and
administrative and other organizational barriers also play a major role.
Although many organizations support the idea of EBP in theory, they do
not always provide the necessary supports in terms of staff release time
and availability of resources. Nurses’ time constraints are a crucial
deterrent to the use of evidence at the bedside. Strong leadership in health
care organizations is essential to making evidence-based practice happen.
RESOURCES FOR EVIDENCE
