Evidence-Based Nursing

Authors

Alba DiCenso, RN, PhD
Donna Ciliska, RN, PhD
Susan Marks, BA, BEd
Ann McKibbon, MLS
Evidence-Based Nursing Editorial Office (Canada)
Health Information Research Unit
McMaster University
Hamilton, Ontario, Canada

Nicky Cullum, RN, PhD
Carl Thompson, RN, PhD
Evidence-Based Nursing Editorial Office (UK)
Centre for Evidence-Based Nursing
University of York
York, UK

Contact

Alba DiCenso
Editor, Evidence-Based Nursing
Health Information Research Unit
McMaster University, HSC 3H6
Hamilton, Ontario L8N 3Z5
Canada
Tel: 905 525-9140 ext 22164
Fax: 905 546-0401

Table of Contents

1. Evidence-Based Nursing - An Introduction
2. Other resources for Evidence-Based Nursing
3. Sample scenarios, search strategies, completed worksheets and CATs for Evidence-Based Nursing

Introduction to evidence-based nursing

Florence Nightingale would probably not recognise the nurse of today. As we move into the next millennium, we expect nurses to care with their hearts and minds; identify patients' actual and potential health problems; and develop research-based strategies to prevent, ameliorate, and comfort. We increasingly expect them to undertake work historically done by doctors; we also expect them to be empathic communicators who are highly educated, critical thinkers, and abreast of all the important research findings.

Research makes a difference. In a meta-analysis designed to determine the contribution of research-based practice to patient outcomes, Heater and colleagues reported that patients who receive research-based nursing care make "sizeable gains" in behavioural knowledge, and physiological and psychosocial outcomes compared with those receiving routine nursing care.²

The process of incorporating good quality research findings into nursing practice is, however, not straightforward. Bostrom and Suter found that only 21% of 1200 practising nurses had implemented a new research finding in the previous six months.³ Luker and Kenrick used qualitative techniques in an exploratory study of community nurse decision-making in the United Kingdom and determined that the nurses had an awareness of research but did not perceive it as informing their practice.⁴ This work also supported previous reports that nurses have difficulty in accessing and appraising published research, either because they do not have access to journals and libraries, or because they have not been taught how to find and appraise research.^{5, 6, 7}

Estabrooks asked staff nurses about the frequency with which they used various sources of knowledge. Most frequently used knowledge sources were found to be experiential, nursing school (even though the average length of time since completing their basic nursing education program was 18 years), workplace sources, physician sources, intuitions, and what has worked for years. Literature (whether in textbook or journal form) was rated in the bottom 5 for frequency. She also asked them to identify the one most common source from which they learned about research findings. While 38.7% identified nursing journals, additional analyses revealed that the primary journals the nurses were reading were not research journals, but rather trade magazines published by nursing professional organisations.⁸

More than 400 nursing journals are listed in Ulrich's International Periodicals Directory,⁹ many of which publish original research, and in a range of languages. Nurses working individually cannot hope to find and read even the highest quality research published each year, particularly when much of the research relevant to nursing is published in non-nursing journals.

When clinical nurses have been taught how to identify and appraise research critically they have responded with enthusiasm, but they have had difficulty in learning and applying these skills in practice, partly because of shifting patterns and workloads.¹⁰ Nurses who were interviewed in a qualitative study of their information needs said that they needed reference sources to be accurate and concise. This is consistent with a survey of midwives working in the northwest of England, who reported great difficulty in assessing the quality of journal articles. These midwives asked for research reports to be more concise, free from jargon, and self-explanatory.¹¹

Research utilisation has been defined as the use of research findings in any or all aspects of one's work as a registered nurse or at its simplest, the use of research.¹² If we use this same definition for 'evidence-based nursing', its meaning is broader than that of 'research utilisation'. The practice of evidence-based nursing involves the following steps: formulation of an answerable question to address a specific patient problem or situation;¹³ systematic searching for the research evidence that could be used to answer the question;^{14, 15} appraisal of the validity, relevance and applicability of the research evidence; integration of the research evidence with other information that might influence the management of the patient's problems: clinical expertise, patient preference for alternative forms of care, and available resources;¹⁶ implementation of the evidence-based practice decision; and finally, evaluation of the outcome of the decision.

Resources to facilitate evidence-based nursing

Evidence-Based Journals
Rather than publishing original research, the objective of these journals is to summarise those studies that are valid and clinically useful. Currently, these journals consist of ACP Journal Club, Evidence-Based Medicine, Evidence-Based Cardiovascular Medicine, Evidence-Based Health Policy and Management, Evidence-Based Mental Health, and Evidence-Based Nursing. While they are all similar in format, we will provide a brief description of Evidence-Based Nursing. The specific purposes of this journal are: to identify, using predefined criteria, the best quantitative and qualitative original and review articles on the meaning, cause, course, assessment, prevention, treatment, or economics of health problems managed by nurses and on quality assurance; to summarise this literature in the form of "structured abstracts" that describe the question, methods, results, and evidence-based conclusions of studies in a reproducible and accurate fashion; and to provide brief commentaries written by practising nurses on the context of each article, its methods, and clinical applications that its findings warrant.

The authors of this module are all involved in the production of Evidence-Based Nursing. Alba DiCenso, Nicky Cullum, and Donna Ciliska are co-editors; Susan Marks and Ann McKibbon are research associates and Carl Thomson is an associate editor. In addition to the abstracts, Evidence-Based Nursing includes an "EBN Notebook" in which we publish short papers about the research process. We have included copies of some of these published to date in this module. Topics include: asking answerable questions; searching for the best evidence, and identifying the best research design to fit the question (Part 1: quantitative designs and Part 2: qualitative designs).

Systematic reviews
We are now at the point in health care research where important questions have often been addressed by more than one study. A systematic review is a method of summarising the findings of all methodologically sound studies addressing the same research question. In a systematic review, eligible research studies are viewed as a population to be systematically sampled and surveyed. Individual study characteristics and results are then abstracted, quantified, coded, and assembled into a database that, if appropriate, is statistically analysed much like other quantitative data. The statistical combination of the results of more than one study, or meta-analysis, effectively increases the sample size and results in a more precise estimate of effect than can be obtained from any of the individual studies used in the meta-analysis.

The Cochrane Collaboration is an international organisation that aims to help people make informed decisions about health by preparing, maintaining, and ensuring the accessibility of rigorous, systematic, and up-to-date reviews (including meta-analyses where appropriate) of the benefits and risks of health care interventions.¹⁷ The Cochrane Library is the product of the Collaboration's work and includes reports and protocols of over 1000 systematic reviews produced within the Collaboration, abstracts of over 1800 reviews summarised and critically appraised by the Centre for Reviews and Dissemination at the University of York, UK, and citations for over 200,000 randomized controlled trials.

Centres for Evidence-Based Nursing
In the past few years, a number of countries, including the UK, Canada, Germany, New Zealand, Australia and others, have created Centres for Evidence-Based Nursing. While the specific goals of these centres vary, most seek to educate nurses through workshops or through formal courses to be evidence-based nurses in practice, education and research; to conduct original research and systematic reviews; and to design and evaluate strategies for disseminating research findings to nurses.

Evidence-based practice guidelines
Clinical practice guidelines are " systematically developed statements to assist practitioner decisions about appropriate health care for specific clinical circumstances"¹⁸ Guidelines can be used to reduce inappropriate variations in practice and to promote the delivery of high quality, evidence-based health care. Guidelines should be based on the best available research evidence, should be developed with representation from as many interested parties as possible, should be tested by professionals uninvolved in their development and in the healthcare setting for feasibility, and should be reviewed regularly and modified to incorporate new knowledge.¹⁹

These are exciting times in nursing. With the increased emphasis on graduate education for nurses, many important research questions related to the practice of nursing are being addressed using rigorous research methods. There is a strong motivation among nurses to apply the findings of research to their practice through evidence-based nursing. To complement these developments, a variety of resources have emerged to help nurses become evidence-based practitioners.

¹ Nightingale F. Notes on nursing what it is and is not. London: Churchill Livingstone, 1946. (First published in 1859)
² Heater BS, Becker AM, Olson R. Nursing interventions and patient outcomes. A meta-analysis of studies. Nurs Res 1988;37:303-7.
³ Bostrom J, Suter WN. Research utilisation: making the link to practice. Journal of Nursing Staff Development 1993;9:28-34.
⁴ Luker KA, Kenrick M. An exploratory study of the sources of influence on the clinical decisions of community nurses. J Adv Nurs 199217:457-66.
⁵ Ketefian S. Application of selected nursing research findings into nursing practice: a pilot study. Nurs Res 1975;24:89-92.
⁶ Blythe J, Royle JA. Assessing nurses' information needs in the work environment. Bull Med Libr Assoc 1993;81:433-5.
⁷ Pearcey PA. Achieving research-based nursing practice. J Adv Nurs 1995;22:33-9.
⁸ Estabrooks CA. Will evidence-based nursing practice make practice perfect? C J Nurs Res 1998;30:15-36.
⁹ Ulrich's international periodicals directory. New York: Bowker, 1996.
¹⁰ Royle JA, Blythe J, Ingram C, DiCenso A, Bhatnager N, Potvin C. The research utilization process: the use of guided imagery to reduce anxiety. Canadian Oncology Nursing Journal 1996;6:20-5.
¹¹ Meah S, Luker KA, Cullum NA. An exploration of midwives' attitudes to research and perceived barriers to research utilisation. Midwifery 1996;12:73-84.
¹² Sackett DL, Rosenberg W, Gray JAM, Haynes RB. Evidence-based medicine: What it is and what it isn't. BMJ 1996;312:71-2.
¹³ Flemming K. Asking answerable questions. Evidence-Based Nursing 1998;1:36-7.
¹⁴ McKibbon KA, Marks S. Searching for the best evidence. Part 1: where to look. Evidence-Based Nursing 1998;1:68-70.
¹⁵ McKibbon KA, Marks S. Searching for the best evidence. Part 2: searching CINAHL and Medline. Evidence-Based Nursing 1998;1:105-7.
¹⁶ DiCenso A, Cullum N, Ciliska D. Implementing evidence-based nursing: some misconceptions. Evidence-Based Nursing 1998;1:38-40.
¹⁷ Jadad AR, Haynes RB. The Cochrane Collaboration - Advances and challenges in improving evidence-based decision making. Medical Decision Making 1998;18:2-9.
¹⁸ Field MJ, Lohr KN. Clinical practice guidelines: directions for a new program. Washington, DC: National Academy Press, 1990.
¹⁹ Thomas L. Clinical practice guidelines. Evidence-Based Nursing 1999;2:38-9.

Other resources for evidence-based nursing

1. DiCenso A, Cullum N, Ciliska D. Implementing evidence-based nursing: some misconceptions [editorial]. Evidence-Based Nursing 1998 Apr;1:38-40.
2. Anne Mulhall, Nursing, research, and the evidence [editorial]. Evidence-Based Nursing 1998 Jan;1:4-6.
3. Flemming K. Asking answerable questions [editorial]. Evidence-Based Nursing 1998 Apr;1:36-7.
4. McKibbon KA, Marks S. Searching for the best evidence. Part 1: where to look [editorial]. Evidence-Based Nursing 1998 Jul;1:68-70.
5. McKibbon KA, Marks S. Searching for the best evidence. Part 2: searching CINAHL and Medline [editorial] Evidence-Based Nursing 1998 Oct;1:105-7.
6. Roberts J, DiCenso A. Identifying the best research design to fit the question. Part 1: quantitative designs [editorial]. Evidence-Based Nursing 1999 Jan;2:4-6.
7. Ploeg J. Identifying the best research design to fit the question. Part 2: qualitative designs [editorial]. Evidence-Based Nursing 1999 Apr;2:36-7.

DiCenso A, Cullum N, Ciliska D. Implementing evidence-based nursing: some misconceptions [editorial]. Evidence-Based Nursing 1998 Apr;1:38-40.

Evidence-based practice isn't new; it's what we have been doing for years

While the recognition of the importance of evidence-based practice is not new, much of the past 20 years has focused on the identification of the barriers to evidence-based practice and the consideration of strategies to overcome these barriers. These barriers include time constraints, limited access to the literature, lack of training in information seeking and critical appraisal skills, a professional ideology that emphasises practical rather than intellectual knowledge, and a work environment that does not encourage information seeking.⁴

We have learned that it is not sufficient to give nursing students a few lectures on the process of doing research and then expect them to use that knowledge throughout their careers in an ongoing process of gathering and interpreting research evidence and implementing findings. Nurses and midwives have been telling researchers for years that they want to deliver research based care, but that they find it difficult to access the research. In a study of health agencies in Ontario, Canada, Mitchell et al found that only 35% of small hospitals (<250 beds) had nursing research journals in their libraries; 38% of health agencies based change in nursing practice on the research process; 15% implemented research utilisation programmes for staff nurses; and 97% wanted assistance in teaching their nursing staff about research utilisation.⁵

Although we have advocated evidence-based nursing for many years, we have struggled with how to make it happen. This struggle is not unique to nursing but common to all health professions, including medicine. Challenged to address this important issue, an international commitment to evidence-based health care has resulted in a number of initiatives to improve access to research findings such as the Cochrane Collaboration, the Evidence-Based Medicine Working Group, critical appraisal skills teaching programmes, centres for evidence-based practice, research utilisation conferences, and evidence-based journals.

Evidence-based nursing leads to `cookbook' nursing and a disregard for individualised patient care

The figure shows a simple model for clinical decisions with 4 components that might influence the management of the patient's problems: clinical expertise, patient preference for alternative forms of care, clinical research evidence, and available resources. It is important to note that clinical expertise and patient preference may override the other components of the model for a given decision. For example, clinical expertise must prevail if the nurse decides that the patient is too frail for a specific intervention that is otherwise `best' for his condition, and the patient's preference will dominate when he declines a treatment that clinical circumstances and research evidence indicate is best for his condition. All of these factors, however, have to be considered in the light of the fact that resources for health care are limited. Most decisions in health care have resource implications; there are likely to be occasions when the potential benefit of an intervention is judged to be outweighed by the potential costs. While individual clinical nurses may not make this judgment, they need to be aware of this important dimension.

In professional training and beyond, we learn the basic mechanisms of disease and pathophysiology and acquire skills in assessment, planning, intervention, and evaluation. We refine these skills by accumulating clinical expertise through observing the correlates and consequences of our actions in dealing with many patients. Many elements of clinical assessment and management require the advanced knowledge that nursing education provides and the expertise that comes with experience.

Evidence from research can help to perfect the expertise but cannot do the examination or sort through the myriad of quantitative and qualitative information that nurses collect during the clinical encounter. Clinical expertise is the crucial element that separates evidence-based nursing from cookbook nursing and the mindless application of rules and guidelines.

Patients have always exercised their preferences for care by choosing alternative treatments, refusing treatment, preparing advance directives (`living wills'), and seeking second opinions. Today's patients have greater access to clinical information than ever before, and some become more knowledgeable about their conditions than their care providers; particularly those with chronic conditions. Although the patient's role in clinical decisions is usually not formalised and is sometimes ignored by care providers, it is an important component of most clinical decisions. Clearly, the best possible scenario is one in which the patient is able to play a full part in making decisions about his or her own health care, having been given an accurate assessment of the current state of knowledge.

Imagine the older person in hospital after a stroke. The nurse caring for this person uses highly developed communication skills, intuition, and clinical experience to get to know the patient and his family. The nurse begins to understand how the patient feels about what is happening to him, and what his goals for rehabilitation might be. As she establishes this rapport, she is in a position to determine if the patient is depressed, anxious, and/or eager to learn about his condition. The relationship that a nurse builds with her patients is important to patients, as shown by Kralik et al in this issue (p63). However, these relationships are enhanced if the nurse is also able to ensure that the caring practices and interventions she uses are safe and effective. Knowing which exercises are effective for patients with hemiplegia, knowing how to prevent their pressure sores, and how to teach them to transfer from a bed to a chair will contribute to high quality patient care.

There is an over-emphasis on randomised controlled trials and systematic reviews in evidence-based health care

In a 1997 issue of the British Journal of Nursing, White stated that: `Perhaps the most obviously flawed assumption is that examining research using RCTs is the best way to evaluate the effectiveness of interventions and a better basis for clinical decision-making than the clinical experience of the practitioner.'⁷

We strongly disagree with White's assertion. History has shown numerous examples of healthcare interventions which, on a patient by patient basis, might appear to be beneficial, but when evaluated using randomised trials have been shown to be of doubtful value, or even harmful. Examples include the use of cover gowns by nurses when caring for normal newborns in the nursery,⁸ and shaving before surgery.⁹ Few of us would want to begin a drug regimen that has not been proved to be safe and effective in a RCT.

More recently, there has been an emphasis on systematic overviews of the research literature. In an overview, eligible research studies are viewed as a population to be systematically sampled and surveyed. Individual study characteristics and results are then abstracted, quantified, coded, and assembled into a database that, if appropriate, is statistically analysed much like other quantitative data. The statistical combination of the results of more than one study, or meta-analysis, effectively increases the sample size and results in a more precise estimate of treatment effect than can be obtained from any of the individual studies used in the meta-analysis. There are 3 overviews in this issue of Evidence-Based Nursing which address the effectiveness of distance medicine technology (Balas et al, p58), compression treatment for venous leg ulcers (Fletcher et al, p50), and psychosocial interventions for children with chronic illnesses (Bauman et al, p43). Through rigorous systematic overviews, nurses are provided with a summary of all the methodologically sound studies related to a specific topic. In most cases, this is much more powerful than the results of any one single study.

Just as randomised trials and systematic overviews are the best designs for evaluating nursing interventions, qualitative studies are the best designs to better understand patients' experiences, attitudes, and beliefs. Results of intervention studies may inform nurses about the optimal effects of an intervention in a sample of patients, but they do not explore and explain the barriers to patient compliance with the intervention, nor how the treatment affects the patient's everyday life, the meaning of illness for the patient, or the adjustment required to accommodate a lifelong treatment regimen. Rigorous qualitative research is based on explicit purposive strategies, in depth analysis of data, and a commitment to examining alternative explanations. In this issue of Evidence-Based Nursing, qualitative studies examine parents' experiences with a critically ill child in the paediatric intensive care unit (Mu and Tomlinson, p60); patients' experiences of nursing (Kralik et al, p63); experiences of long term oxygen therapy (Ring and Danielson, p64); women's role as carers (Wuest, p62); and patterns of violence experienced by homeless battered women (Clarke, p61).

Through Evidence-Based Nursing we hope to convey that good evidence does involve more than RCTs and systematic overviews. Each research design has its purpose, its strengths, and its limitations. The key is ensuring that the right research design is used to answer the question posed.

The ultimate goal of nursing is to deliver to patients the best available care. Despite numerous barriers to using research there continues to be strong motivation among nurses to learn the skills required to practice evidence-based nursing. The application of research findings to practice goes hand in hand with clinical expertise and with patient preferences and values. The types of study designs that form the basis for evidence-based practice will vary depending on the nature of the question asked.

We have attempted to identify and address common misconceptions about evidence-based nursing. Readers are encouraged to comment and to let us know if there are additional impediments to this relatively new initiative in nursing.

¹ Hunt J. Indicators for nursing practice: the use of research findings. J Adv Nurs 1981;6:189-94.
² Gortner SR, Bloch D, Phillips TP. Contributions of nursing research to patient care. J Adv Nurs 1976;1:507-18.
³ Roper N. Justification and use of research in nursing. J Adv Nurs 1977;2:365-71.
⁴ Royle JA, Blythe J, Ingram C, et al. The research utilisation process: the use of guided imagery to reduce anxiety. Canadian Oncology Nursing Journal 1996;6:20-5.
⁵ Mitchell A, Janzen K, Pask E, et al. Assessment of nursing research utilization needs in Ontario health agencies. Can J Nurs Admin 1995;8:77-91.
⁶ Haynes RB, Sackett DL, Gray JAM, et al. Transferring evidence from research into practice. 1. The role of clinical care research evidence in clinical decisions [[editorial]]. ACP Journal Club 1996 Nov-Dec;125:A14-6.
⁷ White S. Evidence-based practice and nursing: the new panacea? British Journal of Nursing 1997;6:175-7.
⁸ Rush J, Fiorino-Chiovitti R, Kaufman K, et al. A randomised controlled trial of a nursery ritual: wearing cover gowns to care for healthy newborns. Birth 1990;17:25-30.
⁹ Hoe NY, Nambiar R. Is preoperative shaving really necessary? Ann Acad Med Singapore 1985;14:700-4.

Anne Mulhall, Nursing, research, and the evidence [editorial]. Evidence-Based Nursing 1998 Jan;1:4-6.

Research has been used to legitimise nursing as a profession, education has been radically reformed to reflect a research base, and academic nurses have built their careers around it. However, despite the length of time that research has been on the agenda and the influential bodies involved, only a moderate proportion of nurses use research as a basis for practice.¹

What has gone wrong?

Tiptoeing in the wake of the movement for evidence-based medicine, however, we must ensure that evidence-based nursing attends to what is important for nursing. Part of the difficulty that practitioners face relates to the ambiguity which research, and particularly `scientific' research, has within nursing. Ambiguous, because we need to be clear as to what nursing is, and what nurses do before we can identify the types of evidence needed to improve the effectiveness of patient care. Then we can explore the type of questions which practitioners need answers to and what sort of research might best provide those answers.

What is nursing about?

What sort of evidence does nursing need?

Picking the research design to fit the question

This way of approaching research is very useful, especially to a discipline concerned with trying to understand the predicaments of patients and their relatives, who find themselves ill, recovering, or facing a lifetime of chronic illness or death. Questions which arise in these areas are less concerned with causation, treatment effectiveness, and economics and more with the meaning which situations have--why has this happened to me? What is my life going to be like from now on? The focus of these questions is on the process, not the outcome. Data about such issues are best obtained by interviews or participant observation. These are aspects of nursing which are less easily measured and quantified. Moreover, some aspects of nursing cannot even be formalised within the written word because they are perceived, or experienced, in an embodied way. For example, how do you record aspects of care such as trust, empathy, or `being there'? Can such aspects be captured within the confines of research as we know it?

Questions of causation, prognosis, and effectiveness are best answered using scientific methods. For example, rates of infection and thrombophlebitis are issues which concern nurses looking after intravenous cannulas. Therefore, nurses might want access to a randomised controlled trial of various ways in which cannula sites are cleansed and dressed to determine if this affects infection rates. Similarly, some very clear economic and organisational questions might be posed by nurses working in day surgery units. Is day surgery cost effective? What are the rates of early readmission to hospital? Other questions could include: what was it like for patients who had day surgery? Did nurses find this was a satisfying way to work? These would be better answered using interpretist approaches which focus on the meaning that different situations have for people. Nurses working with patients with senile dementia might also use this approach for questions such as how to keep these patients safe and yet ensure their right to freedom, or what it is like to live with a relative with senile dementia. Thus different questions require different research designs. No single design has precedence over another, rather the design chosen must fit the particular research question.

Research designs useful to nursing

Maximising the potential of evidence-based nursing

In summary, in embracing evidence-based nursing we must heed these considerations:

• Nursing must discard its suspicion of scientific, quantitative evidence, gather the skills to critique it, and design imaginative trials which will assist in improving many aspects of nursing
• We must promulgate naturalistic/interpretist studies by indicating their usefulness and confirming/explaining their rigour in investigating the social world of health care
• More research is needed into the reality and consequences of adopting evidence-based practice. Can practitioners act on the evidence, or are they being made responsible for activities beyond their control?
• fIt must be emphasised that those concerns which are easily measured or articulated are not the only ones of importance in health care. Space is needed to recognise and explore the knowledge which comes from doing nursing and reflecting on it, to find new channels for speaking of concepts which are not easily accommodated within the discourse of social or natural science--hope, despair, misery, love.

¹ Bostrum J, Suter WN. Research utilisation: making the link with practice. J Nurs Staff Dev 1993;9:28-34.
² Lacey A. Facilitating research based practice by educational intervention. Nurs Educ Today 1996;16:296-301.
³ Pearcey PA. Achieving research based nursing practice. J Adv Nurs 1995;22:33-9.
⁴ Mulhall A. Nursing research: our world not theirs? J Adv Nurs 1997;25:969-76.
⁵ Walby S, Greenwell J, Mackay L, et al. Medicine and nursing: professions in a changing health service. London: Sage, 1994.
⁶ Lawler J. The body in nursing. Edinburgh: Churchill Livingstone, 1997.
⁷ Lawler J. Behind the screens nursing. Edinburgh: Churchill Livingstone, 1991.
⁸ Street AF. Inside nursing: a critical ethnography of clinical nursing practice. New York: State University Press of New York, 1992.
⁹ Madge P, McColl J, Paton J. Impact of a nurse-led home management training programme in children admitted to hospital with acute asthma: a randomised controlled study. Thorax 1997;52:223-8.
¹⁰ Kushi LH, Fee RM, Folsom AR, et al. Physical activity and mortality in postmenopausal women. JAMA 1997;277:1287-92.
¹¹ Rogan F, Shmied V, Barclay L, et al. Becoming a mother: developing a new theory of early motherhood. J Adv Nurs 1997;25:877-85.
¹² Barroso J. Reconstructing my life: becoming a long-term survivor of AIDS. Qual Health Res 1997;7:57-74.
¹³ Thibodeau J, MacRae J. Breast cancer survival: a phenomenological inquiry. Adv Nurs Sci 1997;19:65-74.
¹⁴ Sackett D, Haynes RB. On the need for evidence-based medicine. Evidence-Based Medicine 1995;1:5-6.
¹⁵ Gordon DR Tenacious assumptions in Western biomedicine. In: Lock M, Gordon DR, eds. Biomedicine Examined. London: Kluwer Academic Press, 1988;19-56.

Sample scenarios, searches, completed worksheets and CATs for Evidence-Based Nursing

Clinical scenario

Read the article and decide,

1. Is the evidence from this study valid?
2. If valid, is this evidence important?
3. If valid and important, can you apply this evidence in caring for your patient?

Citation

Are the results of this diagnostic study valid?

Are the valid results of this diagnostic study important?

		Target Disorder Depression		Totals
		Present (case)	Absent (control)
Diagnostic Test Result 2-question instrument	Positive	93 a	189 b	a + b = 282
	Negative	c 4	d 250	c + d = 254
Totals		a + c = 97	b + d = 439	a + b + c + d = 536

Sensitivity = a/(a+c) = 93/97 = 96%

Specificity = d/(b+d) = 250/439=57%

Likelihood Ratio for a positive test result = LR+ = sens/(1-spec) = 0.96/1-0.57 = 2.2

Likelihood Ratio for a negative test result = LR- = (1-sens)/spec = 1-0.96/0.57 =0.07

Positive Predictive Value = a/(a+b) = 93/282 = 33%

Negative Predictive Value = d/(c+d) = 250/254 = 98%

Pre-test Probability (prevalence) = (a+c)/(a+b+c+d) = 97/536 = 18.1%

Pre-test-odds = prevalence/(1-prevalence) = 0.181/0.819 = 0.22

Post-test odds = Pre-test odds x Likelihood Ratio = 0.22x2.2 = 0.48

Post-test Probability = Post-test odds/(Post-test odds + 1) = 0.48/1.48 = 0.32

Can you apply this valid, important evidence about a diagnostic test in caring for your patient?

Additional Notes

Clinical Bottom Line

Negative responses to the 2-question case-finding instrument can rule out depression.

Citation

Clinical Question

Search Terms

The Study

The Evidence

Sensitivity = a/(a+c) = 93/97 = 96%

Specificity = d/(b+d) = 250/439 = 57%

Likelihood Ratio for a positive test result = LR+ = sens/(1-spec) = 0.96/1-0.57 = 2.2

Likelihood Ratio for a negative test result = LR- = (1-sens)/spec = 1-0.96/0.57 = 0.07

Comments

Appraised by

Donna Ciliska RN, PhD.
Associate Professor, School of Nursing
McMaster University, Hamilton, Ontario, Canada.
Fax: (905) 546-0401
Email: ciliska@fhs.mcmaster.ca
Appraised February 1999. Expiry date: 2000

Clinical scenario

Read the article and decide,

1. Is the evidence from this study valid?
2. If valid, is this evidence important?
3. If valid and important, can you apply this evidence in caring for your patient?

Citation

Are the results of this prognosis study valid?

Are the valid results of this prognosis study important?

If you want to calculate a Confidence Interval around the measure of Prognosis:

Clinical Measure	Standard Error (SE)	Typical calculation of CI
Proportion (as in the rate of some prognostic event, etc.) where: the number of patients = n the proportion of these patients who experience the event = p	where p is proportion and n is number of patients	If p = 24/60 = 0.4 (or 40%) & n=60 95% CI is 40% +/- 1.96 x 6.3% or 27.6% to 52.4%
n from your evidence: ________ p from your evidence: ________	where p is proportion and n is number of patients	Your calculation: SE: ____________ 95% CI:

Can you apply this valid, important evidence about prognosis in caring for your patient?

Clinical Bottom Line

Patients with pre-pregnancy neuroticism or psychiatric symptoms, and without other children are at increased risk of a more intense grief reaction.

Citation

Clinical Question

Search Terms

The Study

Prognostic Factors: Risk factors were assessed using the Dutch version of the Symptom Checklist-90 (psychiatric symptoms) and the Dutch Personality Questionnaire (neuroticism, low self-esteem, social inadequacy, general inadequacy, and aggrievedness). Information was also collected on quality of partner relationships, education, employment, religious background, social support, feelings about the pregnancy, pregnancy and conception variables, family demographics, and physical symptoms.

The Outcome: Grief and its categories (active grief, difficulty coping, and despair) measured by the Perinatal Grief Scale immediately after the miscarriage and at 6, 12, and 18 months.

Study Feature	Yes	No	Can't tell
Well-defined sample at uniform (early) stage of illness?	X
Follow-up long enough?	X
Follow-up complete?	X
Blind and objective outcome criteria?		X
Adjustment for other prognostic factors?	X
Validation in an independent "test-set" of patients?		X

The Evidence

Comments

Appraised by

K. Ann McKibbon, MLS.
Research Associate
Health Information Research Unit
McMaster University, Hamilton, Ontario, Canada.
Fax: (905) 546-0401
Email: mckib@fhs.mcmaster.ca
Appraised February 1999. Expiry date: 2000

Clinical scenario

Read the article and decide,

1. Is the evidence from this randomised trial valid?
2. If valid, is this evidence important?
3. If valid and important, can you apply this evidence in caring for your patient?

Citation

Are the results of this single preventive or therapeutic trial valid?

Are the valid results of this randomised trial important?

Median time to resolution of cold symptoms did not differ between groups (9 days for both groups). {Because time to resolution of cold symptoms is a continuous variable, RRR, ARR, NNT cannot be calculated.}

School absences (number of children with absences)		Relative Risk Reduction RRR	Absolute Risk Reduction ARR	Number Needed to Treat NNT
Placebo CER	Zinc lozenges EER	(CER-EER)/CER	CER-EER	1/ARR
20.8%	18.5%	(20.8%-18.5%)/20.8% = 11.1% 95% CI -46.7 to 45.9	20.8% - 18.5% = 2.3%	1/2.3% = 44 pts 95% CI 8 to infinity
Adverse effects (e.g., bad taste reactions; nausea; mouth, tongue or throat irritation; and diarrhoea)		Relative Risk Increase RRI	Absolute Risk Increase ARI	Number Needed to Harm NNH
Placebo CER	Zinc lozenges EER	(CER-EER)/CER	CER-EER	1/ARI
79.8%	98.6%	(79.8%-88.6%)/79.8% = 11.0% 95% CI -21.7 to 3.7	79.8% - 88.6% = 8.8%	1/8.8% = 11 pts 95% CI 6 to infinity

Can you apply this valid, important evidence about a treatment in caring for your patient?

Additional Notes

Clinical Bottom Line

Zinc gluconate lozenges were not effective for reducing symptoms of the common cold in children and adolescents.

Citation

Clinical Question

Search Terms

The Study

Students in Grades 1 to 12 (median age 13 y) who had at least 2 of the following symptoms within the previous 24 hours: cough, headache, hoarseness, muscle ache, nasal congestion, nasal drainage, scratchy throat, sore throat, or sneezing.

Control group (n=125): 3.75 g hard candy lozenges containing sucrose, corn syrup, aminoacetic acid, cherry flavouring oils and placebo (calcium lactate pentahydrate). All students took 3 lozenges each school day; students in grades 1-6 took 2 lozenges each night, and 5 each day on the weekend; students in grades 7 - 12 took 3 lozenges each school night and 6 each day on the weekend. Students were given enough lozenges for 21 days of treatment and instructed to take the lozenges until their cold symptoms completely resolved for 6 hours.

Experimental group(n=124): Same as for control regimen except that lozenges contained zinc gluconate trichydrate, 10 mg instead of placebo.

The Evidence

Comments

Appraised by

Susan Marks, BA, BEd.
Research Associate
Health Information Research Unit
McMaster University, Hamilton, Ontario, Canada.
Fax: (905) 546-0401
Email: sumarks@fhs.mcmaster.ca
Appraised February 1999. Expiry date: 2000

Clinical scenario

Read the article and decide,

1. Is the evidence from this randomised trial valid?
2. If valid, is this evidence important?
3. If valid and important, can you apply this evidence in caring for your patient?

Citation

Are the results of this harm study valid?

Are the valid results from this harm study important?

Although we are told the number of women who used and didn't use OCs and the number who experienced cardiovascular events, it would be inaccurate to complete the table using these raw data. The authors have very appropriately adjusted rates and relative risks for age, parity, social class, obesity, and comorbidity. Based on the adjusted analyses, there was no increased risk of myocardial infarction (RR=1.5, 95% CI 0.6 to 3.2) except in heavy smokers. An increased risk of myocardial infarction was observed in OC users who were heavy smokers compared with non-users (RR=4.9, 95% CI 1.2 to 23.6). There was no increased risk of angina (RR=0.5, 95% CI 0.1 to 1.4), but there was an increased risk of ischaemic stroke (RR=2.9, 95% CI 1.3 to 6.7) that did not persist once OCs were discontinued.

Should these valid, potentially important results of a critical appraisal about a harmful treatment change the treatment of your patient?

¹ The Number of Patients you Need to treat to Harm one of them.

Additional Notes

1. Women already known to be at risk for myocardial infarction or stroke are unlikely to be prescribed OCs.
2. 68% of the woman's years of exposure to OCs in this study was to pills with 50 µg of oestrogen, which is higher than the standard doses in use today. By 1987 only 2.7% of OCs prescribed in the UK contained 50 µg of oestrogen.

Clinical Bottom Line

Increased risk of stroke in patients taking OCs. Lower dose pills are now in common use and may be safer than the higher dose pills examined in this study. Even with the older higher dosages, the absolute risks of ischaemic stroke in OC users are low; 5880 women would need to take OCs for 1 year to cause 1 additional stroke.

Citation

Clinical Question

Search Terms

The Study

The Evidence

^* Adjusted for age, parity, social class, smoking, comorbidity

Comments

Appraised by

Alba DiCenso, RN, PhD.
School of Nursing
McMaster University, Hamilton, Ontario, Canada.
Fax: (905) 546-0401
Email: dicensoa@fhs.mcmaster.ca
Appraised February 1999. Expiry date: 2000

Clinical scenario

Read the article and decide,

1. Is the evidence from this randomised trial valid?
2. If valid, is this evidence important?
3. If valid and important, can you apply this evidence in caring for your patient?

Citation

Are the results of this systematic review of therapy valid?

Can you apply this valid, important evidence from a systematic review in caring for your patients?

Are your patient's values and preferences satisfied by the regimen and its consequences?

Clinical Bottom Line

Patients with asthma who receive self-management education are less likely to be admitted to hospital, have fewer visits to the emergency department, fewer unscheduled visits to the doctor, fewer days off work or school, and less nocturnal asthma. Reductions are greater when self-management education includes a written action plan, self-monitoring, and regular medical review.

Citation

Clinical Question

Search Terms

The Review

Study Selection: Systematic review of randomised controlled trials (RCTs) and controlled clinical trials (CCTs) that studied the effects of asthma education and self-management on health outcomes of people with asthma who were over 16 years of age. Studies were eligible if they measured any of the following health outcomes: asthma admissions, emergency department visits, unscheduled doctor visits, days off work or school, lung function, peak expiratory flow, use of rescue beta-agonists, use of oral corticosteroids, symptom scores, or quality of life scores.

Data Extraction: Data were extracted on study quality, patient and disease characteristics, educational interventions, health outcomes, intermediate outcomes such as knowledge and skills, type of control, and duration of intervention. Interventions were categorised as education, self-monitoring, regular review, written action plan, and optimal self-management.

Multiple independent reviews of individual reports? yes

Tested for heterogeneity? yes

The Evidence

Comments

Appraised by

Nicky Cullum, RN, PhD.
Centre for Evidence Based Nursing
University of York, York, UK, YO10 5DQ
Fax: (905) 546-0401
Email: nac2@york.ac.uk
Appraised February 1999. Expiry date: 2000

Clinical scenario

Read the article and decide,

1. Is the evidence from this randomised trial valid?
2. If valid, is this evidence important?
3. If valid and important, can you apply this evidence in caring for your patient?

Citation

Are the results of this study valid?

Are the results of this study important?

Can I apply these valid, important findings to my patient or their family?

Comments

The Critical Appraisal Skills Programme: Making sense of evidence about effective health care. Oxford: CASP, 1998.

Popay J, Rogers A, Williams G. Rationale and standards for the systematic review of qualitative literature in health services research. Qualitative Health Research 1998;8:341-51 (www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10558335&dopt=Abstract)

Giacomini MK, Cook DJ. A user's guide to qualitative research in health care: part 1: are the results of the study valid? Evidence Based Medicine Working Group, McMaster University, Hamilton, Ontario CA. (forthcoming)

Appraised by

Carl Thompson RN, PhD.
Centre for Evidence Based Nursing
University of York, York, UK, YO10 5DQ.
Email cat4@york.ac.uk

Appraised: February 1999. Expiry date: 2000.