NR 716 Week 6 Critical Appraisal Paper Example

Critical Appraisal of Morrison and Colleagues' 2016 Trial of Emergency Department Nerve Blocks for Hip Fracture, With a Conditional Verdict

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College of Nursing, Chamberlain University

NR 716: Analytic Methods

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Month Day, Year

Critical Appraisal of Morrison and Colleagues' 2016 Trial of Emergency Department Nerve Blocks for Hip Fracture, With a Conditional Verdict

The Paper's Question in Its Own Terms

Morrison et al. (2016) asked whether regional nerve blocks, begun in the emergency department, improve pain and function after hip fracture compared with standard analgesics. The trial was chosen for close reading because it is the closest match in the evidence set to the department's plan: blocks placed by emergency physicians at the time of arrival, in older adults, with outcomes that run from the first hours to six weeks after discharge.

How the Trial Was Conducted

The trial randomized 161 adults with hip fracture at three New York hospitals between April 2009 and March 2013. The 79 in the intervention arm received an ultrasound-guided, single-injection femoral nerve block from an emergency physician on arrival, followed within 24 hours by a continuous fascia iliaca catheter placed by an anesthesiologist. The 82 in the control arm received conventional analgesics. Outcomes were pain on a 0 to 10 scale at several points, distance walked in two minutes on the third day after surgery, walking ability six weeks after discharge on the locomotion items of the Functional Independence Measure and opioid side effects.

Threats Located in This Study

Three threats come from the conduct of this trial specifically, not from a generic list.

First, no sham procedure is described. Patients in the intervention arm knew they had received a block, and so, most likely, did the staff asking them about pain. Pain is a self-reported outcome, and expectation can move it, so the pain differences are the results most open to this bias. Walking distance and side effect reports are less exposed but not immune.

Second, the intervention is two blocks, not one. The early femoral block and the later fascia iliaca catheter cannot be separated in the results. The outcomes on the third day and at six weeks are probably driven more by the catheter, which provided days of analgesia, than by the emergency department injection.

Third, the trial reports many outcomes, and several of the differences sit near the conventional threshold, with p-values of .04 for walking distance and for the six-week locomotion score. With at least eight comparisons reported in the summary alone, one or two findings at that level could arise by chance, and the trial's title claims both pain and functional benefit.

Numbers Turned Into Practice Language

Two hours after arrival, mean pain was 3.5 in the intervention group and 5.3 in the control group, a difference of 1.8 points on a 10-point scale. That is close to the size most clinicians would notice and somewhat smaller than the pooled reduction of about 2.5 points within 30 minutes in the Cochrane review (Guay & Kopp, 2020). In practice, it means a typical patient moves from moderate-to-severe pain to mild-to-moderate pain in the hours when the department is ordering images and waiting for a bed.

Opioid side effects were reported by 3% of the intervention group and 12.4% of the control group, an absolute difference of about 9 percentage points. Roughly one patient in eleven treated would avoid an opioid side effect, if the difference is real. The intervention group also needed 33% to 40% fewer parenteral morphine equivalents.

On the third day after surgery, the intervention group walked a mean of 170.6 feet in two minutes, against 100.0 feet for controls. At six weeks, the locomotion score was 10.3 against 9.1.

The Interval Interpreted

The published summary gives a confidence interval for each group rather than for the difference, which limits how far the intervals can be read. For walking distance, the intervention group's interval runs from 109.3 to 232 feet and the control group's from 65.1 to 134.9. The two ranges overlap, so the true difference could be modest, a few dozen feet, or large, more than a hundred. Both ends would matter to a physical therapist, but only the upper end would change discharge planning. For the six-week locomotion score, the intervals, 9.6 to 11.0 and 8.2 to 10.0, overlap too, and a difference of about one point is small on a scale where walking and stairs are scored together. The pain and side effect results are reported with p-values rather than intervals in the summary, so their precision cannot be judged from it; the full report should be checked before the council meeting.

Significance and Importance Kept Apart

Statistical significance and practical importance answer different questions, and this trial shows why both are needed. The six-week locomotion difference reached significance but is about one point, which may not change what a patient can do at home. The opioid side effect difference is large in practical terms, a fourfold difference in how often patients reported them, yet rests on small numbers: roughly 2 patients against 10 in arms of about 80. A single extra event in either arm would shift it noticeably. Neither result should be presented to the council as settled simply because it crossed .05, and neither should be dismissed because its interval is wide.

Applicability, Said Honestly

The department plans a single fascia iliaca injection, not a femoral block followed by a catheter, and the anesthesia service cannot place catheters for every hip fracture admission. The early pain benefit is the result most likely to transfer, because it was measured two hours after the emergency department block, before any catheter. The functional results are least likely to transfer. The patients were recruited more than a decade ago, and the summary does not say whether people with dementia were enrolled, which matters because they are about a third of the department's population and the group at highest risk of delirium.

A Verdict With Conditions

The trial supports placing a block in the emergency department to reduce early pain and opioid side effects, with two conditions. First, the department should expect a smaller and shorter effect from a single injection than this trial reports for its combined intervention, and should not cite its functional outcomes as a reason to adopt the block. Second, because the pain outcomes were unblinded, they should be read alongside the blinded trials, which found smaller effects, and the department's pilot should measure pain before and after the block itself rather than rely on this estimate (Pasquier et al., 2019).

References

Guay, J., & Kopp, S. (2020). Peripheral nerve blocks for hip fractures in adults. Cochrane Database of Systematic Reviews, 2020(11), Article CD001159. https://doi.org/10.1002/14651858.CD001159.pub3

Morrison, R. S., Dickman, E., Hwang, U., Akhtar, S., Ferguson, T., Huang, J., Jeng, C. L., Nelson, B. P., Rosenblatt, M. A., Silverstein, J. H., Strayer, R. J., Torrillo, T. M., & Todd, K. H. (2016). Regional nerve blocks improve pain and functional outcomes in hip fracture: A randomized controlled trial. Journal of the American Geriatrics Society, 64(12), 2433-2439. https://doi.org/10.1111/jgs.14386

Pasquier, M., Taffe, P., Hugli, O., Borens, O., Kirkham, K. R., & Albrecht, E. (2019). Fascia iliaca block in the emergency department for hip fracture: A randomized, controlled, double-blind trial. BMC Geriatrics, 19, Article 180. https://doi.org/10.1186/s12877-019-1193-0