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Unearthing evidence of clinical effectiveness

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VOL: 97, ISSUE: 18, PAGE NO: 39

E. Andrea Nelson, BSc, RGN, is research fellow, Centre for Evidence-Based Nursing, Department of Health Studies, University of York

How can nurses ensure that their knowledge is up to date? Well, there are various approaches you can take, for example, checking the nursing journals for new research, attending study days and nominating each person in your team as a link person for relevant topics, such as pain control, wound care or continence management. This proactive approach to updating is often supplemented by searching for answers to particular questions that arise in the course of clinical practice, especially when a new batch of nursing students is working with us.

How can nurses ensure that their knowledge is up to date? Well, there are various approaches you can take, for example, checking the nursing journals for new research, attending study days and nominating each person in your team as a link person for relevant topics, such as pain control, wound care or continence management. This proactive approach to updating is often supplemented by searching for answers to particular questions that arise in the course of clinical practice, especially when a new batch of nursing students is working with us.

The information explosion means that no one in clinical practice can ever hope to read all the papers available on all the topics he or she deals with on a daily basis. A search of CINAHL for last year, for example, found 62 papers on mouth care/oral hygiene and 190 on pressure ulcers. It is not likely that anyone would find the time to get through all of them.

Increasing workloads mean that more of us are spending our personal time looking for the answers to clinical questions and keeping up to date, which is good reason to ensure that we use it efficiently.

Reviewing the evidence
One way to use your searching/reading time more efficiently is to find a review of research on the topic rather than all the original papers, which can be expensive and difficult to get hold of. Textbook chapters and review articles in journals offer an overview of original articles and provide summaries of the findings. This reduces an unmanageable amount of information to a reasonable format.

The quality of reviews, however, varies, and it can be difficult to know which to trust. Ideally, they should come with a quality rating, which helps to identify those that may not be trustworthy. For example, those that rely only on some of the original articles, and are therefore potentially misleading, could be identified and discarded.

What are the consequences of poor reviews?
Antman et al (1992) found 143 non-systematic reviews on the use of thrombolytic therapies for people with myocardial infarction. These were about 10 years behind the actual evidence.

If you have only 30 minutes to answer a clinical question or keep up to date, it is essential that you identify ways to maximise the chance of finding a trustworthy review.

When selecting a review, start by asking yourself a couple of questions:

- First, is it trustworthy?

- Second, is it relevant to my patients?

How can I find high-quality reviews?
Health care professionals, consumers, researchers and policy-makers are overwhelmed by unmanageable amounts of information.

In the 1970s, Archie Cochrane, a British epidemiologist, drew attention to our collective ignorance of the effects of health care. He recognised that people who wanted to make informed decisions on health care did not have access to reliable reviews of the evidence. He wrote: 'It is surely a great criticism of our profession that we have not organised a critical summary, by specialty or subspecialty, adapted periodically, of all relevant randomised controlled trials.' First written in 1972, his seminal work has been republished in paperback (Cochrane, 1979).

In 1987, he described a systematic review of randomised controlled trials (RCTs) of care during pregnancy and childbirth as 'a real milestone in the history of randomised trials and in the evaluation of care' and suggested that other specialties should copy the methods used (Cochrane, 1989).

The same year, an examination of the scientific quality of many published reviews showed much to be desired (Mulrow, 1987). As Cochrane had emphasised, reviews of research evidence must be prepared systematically and kept up to date to take account of new evidence.

If this is not done, important effects of health care interventions - good and bad - will not be identified promptly and people using the health care services will be ill-served as a result.

In addition, without systematic up-to-date reviews of previous research, plans for new research will not be well informed. As a result, researchers and funding bodies will miss promising leads and embark on studies asking questions that have already been answered (Antman, 1992).

The Cochrane Collaboration
The Cochrane Collaboration has developed in response to Cochrane's call for systematic up-to-date reviews of all RCTs relevant to health care. It is an international organisation that aims to help people make informed choices on health care by preparing, maintaining and ensuring easy accessibility to systematic reviews of the effects of health care interventions.

Many reviews are relevant to nursing, so nurses need to be able to access and appraise Cochrane reviews. Nursing Times will be publishing a series of Cochrane reviews that are relevant to nurses.

Systematic reviews can be long and a number have been summarised further, for example, in evidence-based journals or Clinical Evidence, a compendium of the best available evidence for effective health care.

- Watch out for our new series of Cochrane reviews, which starts next week

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