NSG 660 Unit 2 single study read-through example

Taking the Spirometer Away: A Read-Through of One Randomized Trial in Bariatric Surgery, and Whether Its Patients Look Like Ours

Student Name

Department of Nursing, Herzing University

NSG 660: Scholarly Practice

Instructor Name

January 20, 2026

Taking the Spirometer Away: A Read-Through of One Randomized Trial in Bariatric Surgery, and Whether Its Patients Look Like Ours

Citation and Stated Aim

Pantel et al. (2017) report a randomized trial published in JAMA Surgery that asked whether removing incentive spirometry from routine care after bariatric surgery would change oxygen levels or lung complications. The stated objective was to determine the effect of postoperative incentive spirometry on low oxygen levels, oxygen saturation, and pulmonary complications after bariatric surgery.

The aim and the paper match: the trial was designed around the same three outcomes it names in its objective and reports all three. That check matters because trials often advertise one question and answer a narrower one. It also matters for this course's working question from Unit 1, which asks almost exactly this comparison, device plus usual care versus usual care alone, in a different surgical population.

The Sample: Where, Who, and How Many

Patients were enrolled at a single tertiary referral teaching hospital between May 2015 and June 2016. All were having bariatric surgery. A total of 224 patients were enrolled and 112 were randomized to each group. Their mean age was 45.6 years, and 174 of the 224 (77.7%) were women. The two groups were similar at baseline.

The sample is the part of this paper that most limits its use on a general surgical floor. The patients were middle-aged, mostly women, and having one kind of operation, most often done laparoscopically. The authors chose them for a reason stated in the paper's opening: obesity combined with foregut surgery puts these patients at high risk of lung complications, which should make any benefit from the device easier to detect. That is a strength for the trial's own question and a limit for anyone reading it about older adults after open bowel surgery.

The report states that analysis was based on the evaluable population, not on everyone randomized. The percentages reported at each time point cannot all be produced from denominators of 112, which suggests that some patients were missing at some measurement times. A reader needs to find how many were evaluable at each point and why the others were missing, because if the missing patients were those with the worst oxygen levels, a no-difference finding could be an artifact of who was left.

What Was Done to Whom

The control group received what the hospital treated as standard care: an incentive spirometer with orders to use it ten times every hour while awake. The test group received no device and no such orders. Both groups otherwise received the hospital's usual postoperative care.

Two features of this design matter. First, it is a noninferiority trial: it was set up to show that leaving out the device is not meaningfully worse, not to show that one approach is better. The margin, the amount of extra harm the investigators would accept as "not worse," is the number that gives the result its meaning, and reporting standards for noninferiority trials require it to be stated and justified in advance (Piaggio et al., 2012), so a reader should locate it in the methods before accepting the conclusion. Second, the control group was told to use the device, but being told is not the same as using it. How often the control patients actually used their spirometers is not reported in the abstract, and without that figure the trial compares an order with no order, not use with no use.

Findings, Reported as Sizes and Directions

The primary outcome was hypoxemia, defined as an arterial oxygen saturation below 92% without supplemental oxygen, measured at 6, 12, and 24 hours after surgery. Rates in the device and no-device groups were 11.9% and 10.4% at 6 hours, 5.4% and 8.2% at 12 hours, and 3.7% and 4.6% at 24 hours. Mean saturations were almost identical at every time point, for example 94.9% in both groups at 6 hours. Pulmonary complications within 30 days occurred in 8 device patients (7.1%) and 4 no-device patients (3.6%).

The direction changes from one time point to the next and the differences are small, which is what no effect usually looks like. The statistical claim, that none of the differences was significant, is separate from the practical one. With 112 patients a group and complication rates under 10%, the trial could miss a difference of a few percentage points in the complication rate, which is the difference a surgical floor would care about. The absence of a significant difference is not proof that there is no difference (Altman & Bland, 1995); it is evidence that any difference is probably small.

The Authors' Conclusion Beside the Finding

The authors conclude that the routine use of incentive spirometry is not recommended after bariatric surgery in its current implementation. The last three words carry most of the weight. The finding supports the claim that giving patients the device with the usual hourly order made no detectable difference in this population. It does not support a broader claim that the device cannot work, because the trial did not test a version in which use was measured and supported. The authors' own qualifier acknowledges this, and it should be kept whenever the study is quoted.

Do These Patients Look Like Ours?

The fit breaks in three places. Age: the trial's mean age was under 46, while the patients on this floor after colectomy or hernia repair are more often in their sixties and seventies, with more chronic lung disease and more smokers. Operation: bariatric surgery on the upper abdomen is usually laparoscopic with a short stay; this floor also cares for patients after open lower abdominal surgery with longer stays and more pain on deep breathing. Setting: a single referral center with a dedicated bariatric pathway will mobilize patients early and consistently, which may leave little room for any added benefit from the device.

The fit holds in one important place: the comparison. This is one of the few trials that holds usual care constant and removes only the device, which is exactly the comparison in the working question. The study is therefore useful evidence about the comparison and weaker evidence about the population. Read together with the respiratory care guideline, which already advises against the device on its own and supports it only inside a package of deep breathing, coughing, walking, and pain control (Restrepo et al., 2011), the trial supports questioning the device as routinely given on this floor, but not stopping it for older patients after open surgery on the strength of this trial alone.

References

Altman, D. G., & Bland, J. M. (1995). Absence of evidence is not evidence of absence. BMJ, 311(7003), 485. https://doi.org/10.1136/bmj.311.7003.485

Pantel, H., Hwang, J., Brams, D., Schnelldorfer, T., & Nepomnayshy, D. (2017). Effect of incentive spirometry on postoperative hypoxemia and pulmonary complications after bariatric surgery: A randomized clinical trial. JAMA Surgery, 152(5), 422-428. https://doi.org/10.1001/jamasurg.2016.4981

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

Restrepo, R. D., Wettstein, R., Wittnebel, L., & Tracy, M. (2011). Incentive spirometry: 2011. Respiratory Care, 56(10), 1600-1604. https://doi.org/10.4187/respcare.01471