What each research design could prove about earplugs, eye masks and ICU delirium, and what it could not, set out family by family for NU504 Unit 2. Searches like "nu 504 unit 2 assignment example", "nu504 unit 2 sample" and "nu504 unit 2 example" land here.
What Each Design Can Prove: A Research Design Brief on Earplugs, Eye Masks and ICU Delirium
[Student Name]
Purdue University Global
NU504: Scientific and Analytic Approaches to Advanced Evidence-Based Practice
Unit 2 Assignment
[Instructor Name]
[Date]
The ICU and its bed count are composites; the design reasoning draws on published methods texts and trials.
Question
Among adults in a mixed intensive care unit, do earplugs and eye masks worn overnight, compared with no sleep aids, lower the incidence of delirium as measured with the CAM-ICU during the ICU stay? The CAM-ICU was developed and validated for patients who cannot speak, including those on mechanical ventilation (Ely et al., 2001), which suits a mixed unit.
Three Levels of Claim
Before any design is chosen, the brief ranks what could be said. Level one: the aids cause less delirium. Level two: using the aids is associated with less delirium. Level three: patients find the aids tolerable and describe how they affect their nights. Each design below is assigned the highest level it can reach (Polit & Beck, 2021).
Design Families
1. Individually randomized trial. Claim: cause, level one. Threat: earplugs cannot be disguised from patients or bedside nurses, so outcome assessment is where bias can enter; the fix is CAM-ICU scoring by assessors who do not know the allocation. One published trial approached this by keeping the earplugs, or a dummy, in a closed canister at the bedside so the scoring staff did not see them (Van Rompaey et al., 2012). Sample: a few hundred patients for a moderate effect. Feasible on 16 beds: only over several years.
2. Cluster randomized trial, by unit or by month. Claim: cause, level one. Threat: needs several units and an analysis that allows for clustering. It answers contamination, since nurses on one unit will start offering earplugs to everyone once they see them work. Feasible on 16 beds: not alone; needs a network.
3. Quasi-experimental before-and-after. Claim: association, level two. Threat: other changes over the same period, such as lighter sedation practice. Published pre-post studies of sleep bundles have reported large drops in delirium (Patel et al., 2014), which is exactly why the design's threat matters. Feasible on 16 beds: yes, within a year.
4. Prospective cohort. Claim: association, level two. Threat: confounding by indication. Sicker patients may be offered earplugs less often, so any association arrives confounded by severity. Feasible: yes.
5. Case-control. Claim: association, level two. Threat: poor fit. Delirium is common in intensive care, and the design is built for rare outcomes, so it adds little here. Feasible: yes, but not recommended.
6. Qualitative description. Claim: description, level three. Threat: transferability. Strength: explains why patients remove the aids at night, which the other designs cannot. Feasible: yes, with a small sample.
Reading the Rows Together
Three patterns run across the six rows. First, the designs that can reach cause are the ones this unit cannot run alone, which is a common and uncomfortable result in unit-based nursing research. Second, the most feasible designs share a single weakness: they compare different patients at different times, so anything else that changed on the unit in the meantime can masquerade as an effect of the aids. Third, only the qualitative row addresses adherence. In one small randomized trial of earplugs and eye masks, nearly a third of patients in the intervention group did not keep the earplugs in all night (Demoule et al., 2017). A design that cannot see why that happens can measure a disappointing effect without being able to explain it.
The sample column deserves a word as well. A mixed ICU of 16 beds with an average stay of three to four days admits roughly 1,500 patients a year, but many will be too sedated to wear the aids, too briefly admitted to be exposed to a night on the unit, or unable to consent. The number eligible for a trial is likely to be a fraction of admissions, which is why the individually randomized row is marked feasible only over several years.
Recommendation
The question asks about cause, so it calls for a randomized trial with blinded outcome assessment, and a 16-bed unit cannot run one alone. What this unit can realistically do is a before-and-after quality improvement project with careful measurement, reported as association, together with a short qualitative component asking patients why they keep or remove the aids. If the unit joins other ICUs in a network, a cluster trial would be the design worth proposing.
References
Demoule, A., Carreira, S., Lavault, S., Pallanca, O., Morawiec, E., Mayaux, J., Arnulf, I., & Similowski, T. (2017). Impact of earplugs and eye mask on sleep in critically ill patients: A prospective randomized study. Critical Care, 21(1), 284. https://doi.org/10.1186/s13054-017-1865-0
Ely, E. W., Inouye, S. K., Bernard, G. R., Gordon, S., Francis, J., May, L., Truman, B., Speroff, T., Gautam, S., Margolin, R., Hart, R. P., & Dittus, R. (2001). Delirium in mechanically ventilated patients: Validity and reliability of the confusion assessment method for the intensive care unit (CAM-ICU). JAMA, 286(21), 2703-2710. https://doi.org/10.1001/jama.286.21.2703
Patel, J., Baldwin, J., Bunting, P., & Laha, S. (2014). The effect of a multicomponent multidisciplinary bundle of interventions on sleep and delirium in medical and surgical intensive care patients. Anaesthesia, 69(6), 540-549. https://doi.org/10.1111/anae.12638
Polit, D. F., & Beck, C. T. (2021). Nursing research: Generating and assessing evidence for nursing practice (11th ed.). Wolters Kluwer.
Van Rompaey, B., Elseviers, M. M., Van Drom, W., Fromont, V., & Jorens, P. G. (2012). The effect of earplugs during the night on the onset of delirium and sleep perception: A randomized controlled trial in intensive care patients. Critical Care, 16(3), R73. https://doi.org/10.1186/cc11330
How this NU504 Unit 2 example is structured
Claims are ranked before designs are. The brief sets out three levels of statement, that the aids cause less delirium, that their use is associated with less, and that patients find them tolerable, then assigns each design family to the highest level it can reach. Randomization reaches cause because it balances measured and unmeasured differences on average; the brief adds that open-label delivery leaves outcome assessment as the place bias can enter, so blinded CAM-ICU assessors are named as the fix. Cluster allocation answers contamination, at the cost of needing several units and an analysis that allows for clustering. The cohort paragraph explains why sicker patients may be offered earplugs less often, so any association arrives confounded. Case-control is dismissed, since delirium is too common in intensive care for that design to add much. Qualitative description is credited with explaining why patients remove the aids.
Get an NU504 Unit 2 example written to your instructions
Give the question you are working on, rough or already polished, plus the Unit 2 instructions and rubric. Each design family is then matched to the claim it could support on that question, and the recommendation stays honest about feasibility. First custom sample free, turned around in 24-48h. The paper above is an original model document written by our desk, not a submitted student paper and not an official Purdue University Global document.
NU504 Unit 2 questions, answered
Is a randomized controlled trial always the strongest design?
For a question about whether an intervention causes an effect, it usually is, because randomization balances groups on factors nobody measured. For other questions it is not: prognosis is often best studied in cohorts, and patients' experience in qualitative work. Strength depends on the match between design and question, and a poorly run trial can support less than a careful cohort.
What is a stepped-wedge design?
A form of cluster randomized trial in which every unit eventually receives the intervention, but the order in which units cross over is randomized. It suits changes that leadership intends to roll out anyway, since no unit is permanently denied the change. The analysis has to account for time trends and clustering, which makes it harder to report than a simple two-arm trial.
Do I need to calculate a sample size for this brief?
Rarely in full. Many prompts at this stage want a reasoned statement of feasibility rather than a power calculation: roughly how many patients a unit admits, what share would be eligible, and whether that could detect a difference of the size the literature suggests. Stating the assumptions openly, with bracketed figures where exact numbers are unknown, is usually enough and reads as careful.