Nurse discretion decided who received a peanut ball in this retrospective cohort, and an MN600 Unit 4 article appraisal traces what that design choice does to a favorable result. Searches like "mn 600 unit 4 assignment example", "mn600 unit 4 sample" and "mn600 unit 4 example" land here.
Critical Appraisal of a Retrospective Cohort Study of Peanut Ball Use and Cesarean Birth Using the JBI Checklist for Cohort Studies
[Student Name]
Purdue University Global
MN600: Evidence-Based Practice Project
Unit 4 Assignment
[Instructor Name]
[Date]
The cohort article appraised here is a composite constructed for appraisal practice; it is not a published study and is not listed in the references. The checklist and comparison sources are real.
The Article in Brief
Composite article appraised: a retrospective cohort study from three hospitals in one health system, covering 2,118 nulliparous, term, singleton, vertex labors with epidural analgesia over 24 months. Peanut ball use was identified from a nursing flowsheet field. The outcome was cesarean birth, which occurred in 508 labors (24.0 percent). Logistic regression adjusted for body mass index, induction of labor, gestational age and birth weight. With peanut ball use, the adjusted odds ratio for cesarean birth was 0.71 (95 percent interval 0.52 to 0.97). The authors concluded that the peanut ball reduces cesarean birth.
JBI Checklist for Cohort Studies
The appraisal uses the JBI critical appraisal checklist for cohort studies (Moola et al., 2020), answering each of its eleven items yes, no, unclear or not applicable, with the methods detail behind each answer.
Item 1, similar groups recruited from the same population: no. Although both groups came from the same hospitals, nurses decided whom to offer the ball at their own discretion. A nurse with time to reposition a patient, or a labor already progressing slowly enough to prompt an intervention, may have determined who received the ball, so the groups may differ in ways that also affect the chance of cesarean birth.
Item 2, exposure measured similarly in both groups: no. The flowsheet field for peanut ball use existed only in the final 14 months of the study. In the first 10 months, use was not charted, so some patients who used a ball are classified as unexposed. That misclassification usually pulls an estimate toward no effect, which means the true association could be stronger or weaker depending on who was misclassified.
Item 3, exposure measured validly and reliably: unclear. The flowsheet records whether a ball was used but not for how long, in which position or how often the patient was repositioned.
Item 4, confounders identified: yes, partly. Body mass index, induction, gestational age and birth weight were identified. Fetal position, cervical dilation at epidural placement, nurse staffing and the individual obstetrician were not. Each of these could plausibly affect both whether a ball was offered and whether a cesarean followed. A posterior fetal position, for example, might prompt a nurse to try the ball and independently raise the chance of cesarean, which would bias the estimate toward harm; a well-staffed shift might make both ball use and patient repositioning more likely, which would bias it toward benefit.
Item 5, strategies to deal with confounding stated: yes, through multivariable regression, but only for the measured confounders.
Item 6, participants free of the outcome at the start: yes. No patient had given birth when the exposure began.
Item 7, outcome measured validly and reliably: yes. Cesarean birth is recorded unambiguously in the birth record.
Item 8, follow-up time sufficient: yes. Every labor was followed to birth.
Item 9, follow-up complete: yes. Every labor ends in a birth, and no patients were lost.
Item 10, strategies for incomplete follow-up: not applicable.
Item 11, appropriate statistical analysis: yes, with a reservation. Logistic regression was appropriate for a binary outcome, and 508 events are enough to support the four covariates used, but the article does not say whether the adjustment set was chosen before the data were analyzed.
The Result in Absolute Terms
An odds ratio of 0.71 is easy to overread. At the unit's own baseline cesarean rate of 29 percent for NTSV patients, the odds of cesarean are 0.29 / 0.71 = 0.41. Multiplying by 0.71 gives odds of 0.29, which corresponds to a risk of about 22.5 percent. If the association were causal and applied to the unit, the peanut ball would prevent about 6 or 7 cesarean births for every 100 NTSV labors with epidurals. The confidence interval runs from a large effect to one close to none.
Comparison With Trial Evidence
Randomized trials address the selection problem that this cohort cannot. One trial reported fewer cesareans with the peanut ball (Tussey et al., 2015), while a trial in nulliparous patients found no difference in cesarean rates, 33 percent against 35 percent (Mercier & Kwan, 2018). The cohort's association falls within the range those trials suggest but cannot settle the disagreement between them. A systematic review of the randomized trials found a trend toward fewer cesarean births that did not reach statistical significance, with a pooled risk ratio of 0.8 and an interval from 0.6 to 1.0 (Grenvik et al., 2019). The cohort's odds ratio is compatible with that estimate, which adds modestly to its credibility.
Strengths of the Study
The study has real strengths that the appraisal credits. It is large, with more than 2,000 labors and more than 500 cesareans, which gives it enough events to estimate an association with reasonable precision. It uses a population defined exactly as the PC-02 measure defines it, so its findings apply to the group the unit is trying to change. Its outcome is objective and completely ascertained. And it reflects real practice across three hospitals, where nurses used the ball under ordinary conditions, which trials with study staff and protocols do not.
What Would Change the Verdict
Three additions would strengthen the study's claim. A propensity score analysis using the unmeasured variables, if they could be abstracted from charts, would reduce the confounding by indication behind Item 1. Restricting the analysis to the 14 months with complete charting would remove the misclassification behind Item 2 and show whether the association grows or shrinks. And a sensitivity analysis estimating how strong an unmeasured confounder would have to be to erase the association would tell a reader how fragile the finding is.
Level and Verdict
Evidence level: IV, a well-designed cohort study, in the hierarchy used in this course (Melnyk & Fineout-Overholt, 2023). Verdict for the evidence matrix: include, with its finding reported as a plausible association rather than a demonstrated effect. Nurse selection of patients and incomplete charting of exposure mean that the cohort cannot show that the ball caused the lower cesarean rate. It is useful mainly as evidence that the practice is feasible across three hospitals and that its association with outcomes is at least not harmful, which matters to a unit deciding whether a pilot is safe to try.
References
Grenvik, J. M., Rosenthal, E., Saccone, G., Della Corte, L., Quist-Nelson, J., Gerkin, R. D., Gimovsky, A. C., Kwan, M., Mercier, R., & Berghella, V. (2019). Peanut ball for decreasing length of labor: A systematic review and meta-analysis of randomized controlled trials. European Journal of Obstetrics and Gynecology and Reproductive Biology, 242, 159-165. https://doi.org/10.1016/j.ejogrb.2019.09.018
Melnyk, B. M., & Fineout-Overholt, E. (2023). Evidence-based practice in nursing and healthcare: A guide to best practice (5th ed.). Wolters Kluwer.
Mercier, R. J., & Kwan, M. (2018). Impact of peanut ball device on the duration of active labor: A randomized control trial. American Journal of Perinatology, 35(10), 1006-1011. https://doi.org/10.1055/s-0038-1636531
Moola, S., Munn, Z., Tufanaru, C., Aromataris, E., Sears, K., Sfetcu, R., Currie, M., Lisy, K., Qureshi, R., Mattis, P., & Mu, P. (2020). Chapter 7: Systematic reviews of etiology and risk. In E. Aromataris & Z. Munn (Eds.), JBI manual for evidence synthesis. JBI. https://doi.org/10.46658/JBIMES-20-08
Tussey, C. M., Botsios, E., Gerkin, R. D., Kelly, L. A., Gamez, J., & Mensik, J. (2015). Reducing length of labor and cesarean surgery rate using a peanut ball for women laboring with an epidural. Journal of Perinatal Education, 24(1), 16-24. https://doi.org/10.1891/1058-1243.24.1.16
How this MN600 Unit 4 example is structured
The appraisal orders its concerns by how far each could move the result, which puts exposure first. Nurses offered balls at their own discretion, so the first checklist item, whether the groups came from comparable circumstances, is answered no: a nurse with spare time, or a labor progressing slowly, may have prompted the ball. The flowsheet field existed only for the final fourteen months, so earlier use went uncharted and some exposed patients sit in the comparison group, an error that usually pulls an estimate toward no effect. Confounders are credited where measured and listed where absent, fetal position and nurse staffing among them. Follow-up is complete, since every labor ends in a birth. The analysis item earns a yes, with one reservation about whether the model's adjustment set was chosen before or after the data were seen. The verdict separates a plausible association from a demonstrated effect.
Get an MN600 Unit 4 example written to your instructions
Which article did your section assign, or did you choose one? Send its full text or citation, name the appraisal tool, whether JBI, CASP, Johns Hopkins or another, and include the Unit 4 prompt and rubric. Every checklist item is answered from the methods. The first custom sample is free, back 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.
MN600 Unit 4 questions, answered
What is confounding by indication?
It happens when the reason a patient receives an intervention is itself linked to the outcome. If nurses reached for a peanut ball when labor stalled, the ball group started out at higher risk of cesarean; if they offered it when they had time, the group may have had calmer, better-staffed labors. Either way the comparison is tilted before the ball does anything, and statistical adjustment cannot fully repair it.
Which checklist should the appraisal use?
Whichever the prompt names, and otherwise one built for the study's design. JBI publishes separate checklists for cohort studies, randomized trials, qualitative research and more; CASP does the same. Applying a trial checklist to a cohort forces answers about randomization that do not fit. Naming the tool and its version at the top lets the marker check each answer against the right questions.
Can a flawed cohort study still inform a practice change?
Yes, within limits. A cohort can show that an association appears in routine care, across more patients and settings than most trials enroll, and that is useful beside trial evidence. It cannot show that the intervention caused the difference. The appraisal says which of those two things the study supports, so the matrix and the proposal ask of it only what it can bear.