This research team was composed of staff nurses, unit nurse educators, department directors, and a physician whose specialty is renal care. Stat istical consultation was through collaboration with a local university's School of Public Health Biostatistics Department.
Study Design and Variables
The study design was an experimental, non-patient laboratory model implemented in an open-air, open-bed environment. The independent variables were the size of diapers, volume of saline added to the diaper, and configuration of the diaper. The dependent variable was the weight of the diaper at selected time intervals (at wetting and every 1-hour post-wetting for 7 hours) (see Table 1 for definitions).
No human subjects were used in this research; consequently, review by the Institutional Review Board was not required. The research study was submitted through the hospital internal nursing review process. Eleven nurse members of the research team participated as data collectors. The principle investigator, a staff nurse, and the senior nurse researcher trained the data collectors in the research protocol in measuring saline, adding saline to each diaper, weighing diapers of each size and configuration, and recording the data. Each data collector was 100% in measuring, weighing, and recording data.
Data were collected on two separate days in a large air-conditioned room that contained tables, chairs, and other equipment needed for data collection located within the hospital. On each day of data collection, the electronic scales were verified by biomedical engineering prior to and at mid-point of data collection. At the start of the research, the specified volume of saline was added to each diaper; the diaper was folded or left unfolded and then weighed. Diapers were weighed in the same order at the following time intervals post-wetting to simulate an 8-hour clinical shift (1-hour, 2-hour, 3-hour, 4-hour, 5-hour, 6-hour, and 7-hour). When weighing the diapers, the data collector waited until the scale had "saved" a result (indicated by a series of beeps) before removing the diaper from the scale. The weight was displayed as a digital read-out numeral on the scale. Two volumes of saline, larger and smaller, were added to each diaper size.
A priori level of statistical significance was set at 0.05; power analysis revealed that a minimum of 10 diapers for each condition (size, volume, and configuration) would be sufficient for significance. Twelve (12) diapers for each condition were used in this study to allow for unusable data. Repeated measures analysis of variance (RMANOVA) with balanced data (F-test) was used to analyze data. Eight measurements were available for each volume and each configuration group. This produced five statistical tests: Volume Effect – overall one volume group differs from the others pooling across time and folding; Folding Effect – overall folded and unfolded groups differ pooling across time and volumes; Time Effect – overall values change over time pooling across volumes and folding; Inter action (time by volume) – the change over time differs in the volume groups pooling over folding; and Interaction (time by folding) – the change over time differs between folded and unfolded groups pooling over volume.