Critique of 'Effect of Time of Day for Urinary Catheter Removal on Voiding Behaviors in Stroke Patie

Jul 01, 04:05 AM

Current Headlines: By Sublett, Cynthia M

Recently, this reviewer examined strategies for helping undergraduate students in nursing understand the research process and find their niche as consumers of research as they move forward to the new graduate role. The need to use the evidence base confronts nurses daily in their practice. While a reference is not immediately available, this reviewer has read journal articles that encourage nurses to read the introduction and the conclusions of a research report to determine applicability of the research to current practice situations. Other authors (Macnee & McCabe, 2008) also advocate teaching research in this manner. The possibility of using the practice became more real when reading the abstract for the study that is the subject of this review. The authors stated that no significant differences were found on any of the identified voiding behaviors. Although the danger may be that the reader might put the study away and assume no applicability to their practice, it is hopeful and probable that many would read further, ask why, and think of other kinds of significance for the study. And, although this method of reading research in nursing is not necessarily the subject of this review, it addresses the importance of looking clearly at all aspects of the study, not putting it aside because significant differences were not found. This critique will examine the design of the current study discovering aspects integral to internal study validity and integrity and then discuss, as the authors have posited, the issue of significance and what it means for the evidence base.

Critique

The study offers readers not only a clearly written report but also a well-designed study. Although internal validity and design integrity have been the focus of past reviews, this study addresses each element so well and so succinctly that they deserve focus in this review as well. The elements of the study, background, and literature review supporting the need for the study, study hypotheses, variable identification and definitions, methodology, data analysis, and discussion, are all easily identifiable and well written in the study.

As is the case with many studies comparing interventions, the intent to improve outcomes is paramount. In the current study on catheter removal times for stroke patients, it is very apparent that this intervention, given success, would have an enormous impact on rehabilitation outcomes with stroke patients if retention or infection is prevented and normal voiding encouraged. Potentially, returning the patient to the home environment at an earlier time would be achieved as would improvement of the patient's quality of life.

Reading this study from the beginning, one immediately finds that the background and literature review clearly support the need to examine how nursing might enhance one of the rehabilitation outcomes for stroke patients. Using prior research on urologic surgery patients, the authors very appropriately applied those outcomes to a new population. It has been the personal experience of this reviewer that many patients fear not being able to urinate following catheter removal. Thus, it is understandable, clinically, that previous research would show that nighttime removal, relaxation, and sleep would enhance initial voiding patterns following this procedure.

A review of literature discussed both dependent and independent study variables including bladder dysfunction in stroke patients, specifically urinary frequency and retention, and the potential for urinary infections from indwelling catheters in all patients. Also referenced was prior, but limited, research on timing of catheter removal related to post-voiding patterns. The research included randomized studies as well as one randomized clinical trial. A gap, the lack of research on stroke patients regarding the voiding outcome, was also noted.

The hypothesis, as a predictor, makes a statement of relationship between variables and may state a direction in the relationship or only indicate that the relationship will be different than another group or control group (Polit & Beck, 2006). Researchers write hypotheses in studies when they have a significant amount of background information for the study. Although there were not many studies in the literature review, what existed was strong in suggestion of relationships. Four directional study hypotheses were presented in the current study in a very clear manner addressing the impact of the independent variable, indwelling urinary catheter removal time, on the dependent variables, time interval to first void, volume of urine in first void, post-void residual urine after first void, and number of patients requiring recatheterization. Relationships between the catheter removal time and the dependent variables are clearly stated as is the direction of each relationship. Generated from the literature review, the hypotheses are testable, measurable, and lend themselves well to the randomized comparative study design.

The description of methodology was impressive. Usual items included are design identification and description, sampling, data collection tools and procedures and their reliability and validity, and measurement (Burns & Grove, 2005; Polit & Beck, 2006). All items were detailed in their description in the methods section of the article. By choosing a randomized design, the researchers gave themselves the best possibility for equivalence of participants in the two groups. Using random assignment to meet the criteria of a random design, they enhanced study validity by eliminating the impact of group differences on study results. Additionally, measuring and describing demographic and other potentially extraneous variables eliminated their possible influence on the study results. This open identification of group differences rather than assuming group equivalence further increased validity of the study.

An internally valid study design assures that the treatment is controlled by consistency in its implementation (Burns & Grove, 2005). In a detailed description of data collection following indwelling catheter removal, the current study meets the stated criterion. Each variable was operationally defined and the data collected about the dependent variables was based on each treatment time. The data collection tool for recording the data was developed by the researchers. However, the data collection instruments that measured each dependent variable were identified in the operational definitions and included references to their accuracy of measurement with a citation of prior research that used the instruments or a description of the precision of the instrument. Assuring that readers know that measurement is accurate and consistent and that results are derived from accurate measurement, reliability and validity are important for researchers to address in a research report.

Ethical aspects of the study were addressed. Institutional review board approval was obtained, one assumes from the rehabilitation center where the study was conducted. Each patient was asked to give informed consent prior to participation, and, the patients' physicians also consented for their patients to participate in the study and provided the order for catheter removal for their patients. To protect human rights, participation in a research study to determine effective outcomes of clinical care must do no harm, assure the right to self-determination, privacy, and fair treatment. In the opinion of this reviewer, the researchers protected the patients in this study from harm since no specific catheter removal time had been determined to be superior for stroke patients, and the intervention was the same except for time. No patient names or facilities were mentioned in the results and only aggregate data were provided to protect privacy.

The sampling method is one of convenience based on the location of the study and patients who met the inclusion criteria. As mentioned earlier, the researchers used a random assignment to groups following the recruitment of the participant based on inclusion criteria and informed consent. Random sampling also increases study validity. However, in studies such as the one under current review, the existence of a large available population from which to conduct a random sampling in a reasonable time frame may not be feasible as was the case in this study. The researchers did appropriately conduct a power analysis to determine the sample size that offered the best chance for the study to achieve significance but were unable to achieve it because of the time factor. In the power analysis calculation, they assumed a large effect size at the 0.05 level of significance and a power of 0.8. Effect size that is large is 0.7 or 0.8 or higher (Burns & Grove, 2005; Polit & Beck, 2006). While it is not inappropriate to have a large effect size based on the support of prior research, often, in new research areas, the effect size is medium or small necessitating a larger sample size. Even though the researchers anticipated a strong relationship between the timing of the indwelling catheter removal and the dependent variables, it is possible that the new patient population warranted a smaller effect size and larger sample size to achieve significant results. The sample was described using percentages to quantify demographic variables. Means and standard deviations were calculated on the dependent variables (DV) of the first three hypotheses (interval/ratio data). Independent t-tests were performed to determine significant differences between the groups on each DV. Chi square was used to examine the fourth hypothesis denoting the need for recatheterization (nominal data). All statistics were appropriate based on level of measurement and provided an answer to the stated hypothesis. Data in the tables and in the data analysis discussion were clear and addressed the answers to the hypotheses stated by the researchers.

In the current study, the null or statistical hypothesis was supported (Polit & Beck, 2004). No statistical significance at p +- 0.05 was found between the 10:00 p.m. and 7:00 a.m. removal times on any dependent variable indicating no group differences. Researchers and readers are left to question why this would happen in a study that was well designed. The researchers were very honest in their discussion of possible reasons for the lack of difference. One possibility is the heterogeneity of stroke patients as evidenced by the large standard deviations. They indicated the need for a larger sample size to address this concern. Thus, unanticipated by the researchers, extraneous variables within the population of stroke patients may have influenced the outcome of the study. Although the background data were strong to support the hypotheses related to catheter removal times in one population of patients, there may not have been sufficient research to suggest that a population such as stroke patients would perform in the same manner as the urologic surgery patients.

One additional randomized controlled trial (Webster et al., 2006) found by this reviewer studied the effect of 10:00 p.m. versus 6:00 a.m. removal times on the general hospital population of 210 medical and surgical patients to determine whether patients might be discharged earlier. The study found that, while the hospital stay in a group of surgical patients was shorter, it was not a significant result. Although the length of time to first void was longer and was a statistically significant result, volume of first void was not a significant result. These results corroborate the results of two hypotheses in the current study and may suggest that there are other factors that influence the outcomes for stroke patients and general medical and surgical patients other than urology patients. Based on the addition of this study to the literature review, one might wonder if, in fact, there may be no difference in groups of stroke patients based on time of removal of the indwelling urinary catheter.

Application to the Evidence-Base

The current study was reviewed in a traditional manner from background to conclusions, and not as suggested at the beginning of this column. However, had it been reviewed by examining the introduction and conclusions, the results would have been similar. Readers would need to proceed through the study to find substantiation for the researchers' conclusions.

The researchers addressed concerns that most reviewers and readers will have about this study. While it was the first reaction of this reviewer that the reason for lack of significance was more than sample size, it, along with the new and very heterogeneous stroke population, may be the major factor. Or, maybe there really is no difference. There is no doubt that this study was well designed and conducted, and easy to read and understand as a written report. Only after review of more details of the report might one posit reasons why the study did not achieve significant results.

Without statistical significance, the study will not contribute to a change in practice (Melnyk & Fineout-Overholt, 2005). However, this reviewer agrees that there is clinical significance, as the researchers suggest, for having a consistent policy for indwelling catheter removal to decrease infection and retention problems post catheter removal following a stroke. Clinically, stroke patients will benefit with improved outcomes from the consistency of care that this study is suggesting. With one randomized controlled trial on a more general hospital population supporting, in part, the findings of the current study, hopefully, the researchers will be encouraged to pursue other possible related opportunities. It is a worthwhile topic and study, adding to the body of nursing knowledge that seeks answers to urinary problems of stroke patients during the rehabilitation phase of their illness. Through future studies on the topic, stroke patients will likely be supported with more definitive care guidelines ultimately enhancing their quality of life.

Coleman Gross, J., Hardin-Fanning, F., Kain, M., Faulkner, E.A., & Goodrich, S. (2007). Effect of time of day for urinary catheter removal on voiding behaviors in stroke patients. Urologic Nursing, 27(3), 229-233.

References

Burns, N., & Grove, S. (2005). The practice of nursing research: Conduct, critique, and utilization (5th ed.). St. Louis, MO: Elsevier Saunders.

Macnee, C.L., & McCabe, S. (2008). Understanding nursing research: Reading and using research in evidence-based practice (2nd ed.). Philadelphia: Wolters Kluwer-Lippincott Williams & Wilkins.

Melnyk, B., & Fineout-Overholt, E. (2005). Evidence based practice in nursing and healthcare: A guide to best practice. Philadelphia: Lippincott, Williams, & Wilkins.

Polit, D., & Beck, C. (2006). Essentials of nursing research: Methods, appraisal, and utilization (6th ed.). Philadelphia: Lippincott, Williams & Wilkins.

Webster, J., Osborne, S., Woollett, K., Shearer, J., Courtney, M., & Anderson, D. (2006). Does evening removal of urinary catheters shorten hospital stay among general hospital patients?: A randomized controlled trial. Journal of Wound, Ostomy & Continence Nursing, 33(2), 156-163.

Cynthia M. Sublett, DNSc, RN, is an Adjunct Faculty Member, Xavier University, Cincinnati, OH.

Copyright Anthony J. Jannetti, Inc. Jun 2007

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