Evidence-Based Practice in Nursing: Meta-Analysis - Assignment Example

METAANALYSIS CRITIQUE FOR META-ANALYSIS ______________ ___________ _______________________ Critique for meta-analysis Introduction "Meta-analysis is the statistical method used to obtain a single-effect measure of the summarized studies included in the review" (Johnston, 2005). The goal is to bring together all of the studies around a particular clinical question and, using rigorous inclusion and exclusion criteria, analyze studies similar enough to statistically combine the results in order to quantify the effectiveness of the intervention under study. In the present instance a Meta analysis titled "Reducing Venipuncture and Intravenous Insertion Pain With Eutectic Mixture of Local Anesthetic: A Meta-Analysis" authored by Susan Jane Fetzer has been given. The critical appraisal of this meta-analysis is carried in paragraphs that follow. The Question 1 The purpose of this study was to identify and synthesize published research on the effectiveness of EMLA cream in reducing VE and IV insertion pain. A meta-analytic approach was used to answer the following questions: 1. What is the magnitude of the effect of EMLA cream on VE and IV pains 2. Is the effect size of EMLA cream on VE and IV pains moderated by the following variables: study publication date, sample age, sample size, sample health status, anatomical puncture site, duration of application, method of pain measurement and research design (Fetzer,2001).Research question 1 is direct and useful clinical question as it encourage/discourage clinical use of EMLA in VE & IV whereas question 2 tends to encourage/discourage such use via evidence on several other variables important among them being sample size, sample health status, premedication, anatomical puncture site and duration of application. The topic had immediate relevance for nursing profession as both IV &VE are widely practiced nursing techniques. While substantial agreement was achieved on coding of the substantive variables, methodological variables and miscellaneous variables; resolution of disagreements was not elaborated and two raters were not identified. Search Strategy 2 The meta-analysis clearly defined the inclusion and exclusion criteria for selecting primary studies. The databases used by the reviewers were identified and were appropriate. All of the keywords were identified and were adequate. The reviewers documented the use of adequate supplementary efforts to identify relevant studies, including non-published studies. The Sample 3 The search strategy yielded an adequate sample (number) of studies-19. Though it was not clearly stated if the sample size in each included study was adequate nevertheless there was substantial agreement on 'sample size' methodological variable. The reviewers did not attempt to contact the original researchers for additional information. For instance several studies failed to report test statistics or raw data, in these cases conservative estimates of study outcomes were made from the provided raw data. Rationale for excluded studies was clearly provided. 4 Quality Appraisal 5 A quality index for each study was calculated based on the criteria used by Beck (1995). Reviewers did not indicate that all reviewed primary studies were of high methodological quality though they coded 8 methodological variables and two raters had 97% agreement on coding of such variables.Interrater agreement percentages were reported for all categories of the coded variables but resolution of disagreement(though minor )was not reported. The methodological comparability of the included studies was specified by means of coding 8 methodological variables as above and coding agreement thereupon. As the inclusion criteria was well defined to have comparable clinical situations and since the coding of substantive variables yielded 100 % agreement between two raters combining the studies made sense. Interventions were defined to be more or less similar through study inclusion criteria (e.g. another anesthetic treatment or dermal pain caused by laser energy or pinprick resulted in exclusion). 6 The Data Set 7 Two raters were used to code the various variables of the studies. Seven reports, published between 1985 and 1999, composed the corpus of studies to determine the magnitude of the effect of EMLA cream on VE pain. The sample sizes for the studies ranged from 18 to 140 subjects with a total sample size of 542 for the meta-analysis. Thirteen reports, published between 1982 and 1998, were identified that studied the effect of EMLA cream on IV insertion pain. The sample sizes for the studies ranged from 12 to 119 subjects. These were adequate for subgroup analysis. The Meta analysis made it possible to compute the effect sizes for a sufficient number of studies in the sample. 8 Data Analysis 9 Advanced BASIC Meta-Analysis software was used to compute effect sizes for each study. When necessary test statistics were not provided, available raw data was used to reconstruct the appropriate test. Fail-safe number was calculated to assess if data from missed studies would invalidate the conclusions of the meta-analysis. Tests of homogeneity (Tests for significance levels and for effect sizes) were conducted to ascertain if the differences in study outcomes can be attributed to sampling error alone and not study characteristics. Effect sizes were computed three different ways: unweighted, weighted by sample size, and weighted by quality score. 10 Conclusions 11 This meta-analysis indicates that EMLA cream has a large effect on VE pain and a large effect on IV insertion pain. Examination of the mean weighted effect sizes between VE and IV indicates that the effect of EMLA is consistent across both procedures. Patients who receive EMLA cream report a lower pain experience than those who do not receive EMLA cream by at least one standard deviation. EMLA's beneficial effect was found similar both for premedicated and nonpremedicated subjects. Intravenous insertion technique, as reflected by the IV therapist or insertion site, also did not appear to influence effect size. The findings showed no moderating effect of age, indicating that both children and adults undergoing VE or IV insertion can obtain a large benefit from EMLA application. The findings also showed no moderating effect of EMLA application duration. In view of the findings of this meta-analysis, the use of EMLA cream to reduce VE and IV insertion pain is recommended(Fetzer,2001).. Thus the reviewers drew reasonable conclusions about the quality, quantity, and consistency of the evidence and considered all important patient outcomes. They also set limitations of the review well providing for exceptions, cautions and biases. Reviewers also clearly brought about the implications for nursing practice. 12 How Can I Apply the Results to Patient Care EMLA use has been evidenced to be beneficial both in VE and IV even in the presence of differing conditions and variables. However in healthcare systems that have scarce or rationed resources, the cost of one application of EMLA can be prohibitive, therefore patients at high risk for VE or IV insertion pain and its side effects should be identified for EMLA administration. ). Patients with a history of vasovagal reaction to needles should be prepared with EMLA cream. Patients, particularly children, who will be requiring repeated VE or IV insertion for chronic conditions might also be good candidates for EMLA cream(Fetzer,2001). 13 References 14 Johnston, L. (2005). Critically appraising quantitative evidence. In B. M. Melnyk & E. Fineout-Overhold. Evidence-based practice in nursing & healthcare: A guide to best practice (pp. 79-125). Philadelphia: Lippincott . 15 Fetzer, Susan Jane(2002). Reducing Venipuncture and Intravenous Insertion Pain With Eutectic Mixture of Local Anesthetic: A Meta-Analysis. Nursing Research. Official Journal of the Eastern Nursing Research Society and the Western Institute of Nursing.51(2).pp 119-124. Lippincott Williams & Wilkins, Inc. Read More