NSG 324 Unit 5 single research article critique example

A Methods Critique of Rickard et al. (2012), a Trial of Replacing IV Catheters Only When Needed

Student Name

Department of Nursing, Herzing University

NSG 324: Evidence Based Practice in Nursing

Instructor Name

February 18, 2026

A Methods Critique of Rickard et al. (2012), a Trial of Replacing IV Catheters Only When Needed

The Study in Brief

Rickard et al. (2012) conducted a randomized controlled trial in three hospitals in Queensland, Australia, enrolling 3,283 adult patients with peripheral intravenous catheters. Patients were randomly assigned either to routine replacement of their catheters every three days or to replacement only when clinically indicated, meaning when the catheter was no longer needed or a complication appeared. The primary outcome was phlebitis. The trial was designed to test equivalence: whether the two strategies produced phlebitis rates within a prespecified margin of 3 percentage points of each other. Phlebitis occurred in about 7% of patients in each group, and the authors concluded that the strategies were equivalent for this outcome, with clinically indicated replacement using fewer catheters and costing less.

I read the study because it is the largest trial in the Cochrane review that supports my unit's proposed policy change. This critique concentrates on the methods, because the question for my unit is whether the design justifies relying on the result.

Design: Why Equivalence, and Is the Margin Reasonable?

The choice of an equivalence design fits the question. The authors were not trying to show that clinically indicated replacement is better, but that it is not meaningfully worse or better, which would justify the less invasive and cheaper strategy. Equivalence and noninferiority trials must state their margin in advance and justify it clinically, because the conclusion depends entirely on it (Piaggio et al., 2012). A 3-percentage-point margin means the study would accept, as equivalent, a strategy that caused up to 3 more cases of phlebitis per 100 patients. For a mostly mild, self-limiting complication, that seems a reasonable clinical judgment, but a reader should notice that it is a judgment. A unit whose patients are at higher risk from phlebitis, for example patients receiving irritant infusions, might set the bar differently.

Analysis by intention to treat, which counts every patient in the arm they were randomly assigned to, whatever care they then received, is the conservative choice in a superiority trial but can bias an equivalence trial toward finding no difference, because protocol violations tend to make the two groups more alike. A strong equivalence report presents a per-protocol analysis as well, and a reader should check that both analyses agree.

Sampling and Allocation

The sample size is large, and with three hospitals, the findings do not rest on the habits of a single institution. Random assignment protects against the most serious threat in an intervention study, systematic differences between groups at the start. The reader should confirm how allocation was concealed, meaning whether the person enrolling a patient could know or predict the next assignment, since unconcealed allocation allows enrolling staff to steer patients who seem at higher risk into one group (Polit & Beck, 2021).

Inclusion was limited to adults, and the trial was conducted in Australian hospitals with their own insertion practices, staffing, and catheter products. Those differences do not invalidate the result, but they limit how directly it transfers to a U.S. medical-surgical unit.

Measurement of the Outcome

Phlebitis is a judgment, not a laboratory value. It is diagnosed from signs such as pain, redness, swelling, and a palpable cord, and different nurses can rate the same site differently. The critique therefore asks three questions. Was phlebitis defined with explicit criteria, applied the same way in both groups? Were the people assessing sites trained, and was their agreement checked? And could they know which group a patient was in?

Blinding was not possible for patients or clinical staff, because the age of a catheter and the plan for its replacement are visible. If site assessors also knew the group assignment, their expectations could influence borderline ratings, a form of detection bias. With an outcome as subjective as phlebitis, that is the study's most important potential weakness, and an honest reading should state it rather than assume it away.

The Rare Outcome

The outcome nurses most fear from a catheter left in place is bloodstream infection. Such infections from peripheral catheters are rare, and very few occurred in either group of this trial. Even with more than 3,000 patients, a trial cannot show that two strategies are equivalent for an outcome that almost never happens; it can only show that neither strategy produced a noticeable number. The trial answers the phlebitis question well and the infection question only weakly, which is why the systematic review that pools this trial with others matters for that outcome.

Comparator and Relevance to My Unit

The routine group in this trial had catheters replaced every three days, while my unit's current policy is every 96 hours, or four days. The trial therefore compared clinically indicated replacement with a schedule slightly more frequent than ours. This does not weaken the trial's internal validity, but it matters for applying it. If anything, a four-day routine schedule is closer to clinically indicated replacement than a three-day one, so the difference between my unit's current policy and the proposed one is smaller than the difference the trial tested. Catheters left in place in that arm of the trial were checked on a set schedule. The result applies to a policy that includes that assessment, not to leaving catheters in place without it.

Overall Judgment

This is a well-designed and large trial, appropriate in design for its question, with a clearly stated margin. Its main weaknesses are the subjective primary outcome combined with the impossibility of blinding, limited power for bloodstream infection, and a comparator that differs from U.S. practice. On balance, it provides strong evidence that clinically indicated replacement with regular assessment does not increase phlebitis compared with routine replacement, and it should be used alongside the systematic review rather than alone. Its limits are the kind any trial of a nursing practice faces, and none of them suggests the result is wrong; they indicate where the unit should watch closely after the change. For my unit, the practical conclusion is that the proposed policy is supported, provided that site assessment every shift is built into it and monitored.

References

Piaggio, G., Elbourne, D. R., Pocock, S. J., Evans, S. J. W., Altman, D. G., & CONSORT Group. (2012). Reporting of noninferiority and equivalence randomized trials: Extension of the CONSORT 2010 statement. JAMA, 308(24), 2594-2604. https://doi.org/10.1001/jama.2012.87802

Polit, D. F., & Beck, C. T. (2021). Nursing research: Generating and assessing evidence for nursing practice (11th ed.). Wolters Kluwer.

Rickard, C. M., Webster, J., Wallis, M. C., Marsh, N., McGrail, M. R., French, V., Foster, L., Gallagher, P., Gowardman, J. R., Zhang, L., McClymont, A., & Whitby, M. (2012). Routine versus clinically indicated replacement of peripheral intravenous catheters: A randomised controlled equivalence trial. The Lancet, 380(9847), 1066-1074. https://doi.org/10.1016/S0140-6736(12)61082-4