This paper critically analyzes a quantitative nursing research study by Metheny, Davis-Jackson, and Stewart (2010) examining the effectiveness of an Aspiration Risk-Reduction Protocol (ARRP) in critically ill, mechanically ventilated adult patients receiving tube feedings. The analysis evaluates the study's quasi-experimental two-group design, its three-pronged intervention strategy, statistical methods employed, ethical considerations, and the limitations of the findings. The paper discusses how the ARRP significantly reduced aspiration and pneumonia rates compared to usual care and considers the implications of uncontrolled group differences, sample size disparities, and the exploratory nature of the research for broader clinical application.
The Nursing Research article "Effectiveness of an Aspiration Risk-Reduction Protocol" addresses a proposed method to reduce the risk of aspiration in critically ill patients through a three-pronged intervention strategy. The intervention strategy components include: maintaining head-of-bed elevation at 30 degrees or higher, unless contraindicated; inserting feeding tubes into the distal small bowel when indicated; and using an algorithmic approach for high gastric residual volumes (Metheny, Davis-Jackson & Stewart, 2010, p. 1).
The study used a two-group quasi-experimental design with critically ill, mechanically ventilated adult patients receiving tube feedings. A total of 329 patients were in the control population and 145 in the experimental group (Metheny, Davis-Jackson & Stewart, 2010, p. 1). All patients were drawn from the same five ICUs at a Level I trauma center located in the Midwest (Metheny, Davis-Jackson & Stewart, 2010, p. 3).
One ethical concern inherent in this study design is the lack of treatment given to the control group — treatment that could potentially have benefited those patients. Ultimately, in comparing outcomes between the two groups, aspiration was much lower in the Aspiration Risk-Reduction Protocol (ARRP) group than in the control group (39% versus 88%). Pneumonia rates were also lower in the experimental ARRP group (19% versus 48%), as measured using the Clinical Pulmonary Infection Score (CPIS) (Metheny, Davis-Jackson & Stewart, 2010, pp. 1, 5).
Levels of consciousness, levels of sedation, and severity of disease were also assessed in both groups before and after the experiment. By all measured indicators of overall wellness, the ARRP group was judged to be in better health than the control group (Metheny, Davis-Jackson & Stewart, 2010, p. 5).
Data collection was descriptive in nature and taken at face value. To determine the effect of the ARRP on frequency of aspiration, a t-test for independent groups was used to compare patients in the usual-care and ARRP groups on the mean percentage of pepsin-positive tracheal secretions. To determine the effect of the ARRP on the incidence of pneumonia, a z-test for comparing proportions in independent groups was used to compare the proportion of usual-care patients with the proportion of ARRP patients who had a positive CPIS for pneumonia on Day 4. Significant baseline differences between the two groups were controlled for in the analyses.
To evaluate the effect of the ARRP on hospital resources, the usual-care and ARRP groups were compared using a z-test from the Mann-Whitney U procedure, because the secondary outcomes of hospital length of stay, ICU length of stay, and days of ventilator use had skewed distributions (Metheny, Davis-Jackson & Stewart, 2010, p. 5). Using two separate trials of control and experimental groups was intended to illustrate the reliability of the data. On the hierarchy of evidence, the design was quasi-experimental in nature, given that conditions were not strictly controlled and the experimental group was considerably smaller than the control group.
"Design weaknesses, uncontrolled variables, and scope"
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