Evaluation of Dexmedetomidine on Post-operative Narcotic Requirements and Pain Scores in Bariatric Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of Dexmedetomidine on Post-operative Narcotic Requirements and Pain Scores in Bariatric Patients (NCT02604940), a randomized phase 4 study. The primary outcome is Quantity of Narcotic Utilized by Patient for Pain in Milligrams at 240 Minutes.

2. Clinical Question

The question is about a specific treatment contrast, setting, and measurement time: one intraoperative dose in bariatric surgery patients, followed by recorded hydromorphone use in the recovery unit. It does not directly address narcotic use over the entire postoperative period, pain management after discharge, or outcomes in other surgical populations. The registry summary also names pain scores and physiological measures as secondary outcomes, but the primary endpoint is the quantity of narcotic recorded at 240 minutes.

3. Trial Design

The registry describes a phase 4, randomized, double-masked, parallel-group trial. Participants were assigned to dexmedetomidine or normal saline during bariatric surgery. The registry reports total enrollment of 46. The posted primary outcome results include 26 participants in the dexmedetomidine group and 20 in the normal saline group. The method used to generate the random sequence, the allocation-concealment process, and the details of who was masked are not reported in the registry record.

The intervention description places dexmedetomidine at the beginning of surgical closure, given intravenously as 1mcg/kg over 10 minutes. The control description says normal saline was given over 15 minutes at the beginning of surgical closure. The brief summary says both groups received a standard anesthetic and describes fentanyl and intravenous acetaminophen as part of the regimen. It also describes postoperative patient-controlled analgesia with hydromorphone, with the amount used recorded in the electronic health record.

The primary endpoint was measured at 240 minutes after arrival in the post-anesthesia care unit. The secondary outcome descriptions include pain score, heart rate, blood pressure, oxygen saturation, and respiratory rate. The brief summary says measurements were collected at 30, 60, 90, 120, and 240 minutes, but the posted secondary results give a 240-minute value for pain score, heart rate, and oxygen saturation. Numerical secondary results for blood pressure and respiratory rate are not reported in the registry record.

The record identifies West Virginia University as sponsor, gives a study start of 2014-08, a primary completion date of 2018-06-25, and a completed status. The original protocol details, recruitment flow, participant disposition, and reasons for any differences between enrollment and the outcome-specific group counts are not reported in the registry record. The registry record also does not report the trial's original sample-size justification or a detailed statistical analysis plan.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Quantity of Narcotic Utilized by Patient for Pain in Milligrams at 240 Minutes, measured over At 240 minutes after arriving in Post Anesthesia care Unit.

The primary endpoint is the quantity of narcotic delivered through a patient-controlled analgesia pump, measured in milligrams at 240 minutes after arrival in the post-anesthesia care unit. The registry describes the pump medication as hydromorphone and says its amount was recorded by the recovery-unit nurse in the electronic health record. The endpoint is summarized as a group mean with a standard deviation.

This measure addresses the study's stated question about postoperative narcotic requirements: it records medication delivered during the specified recovery period rather than relying only on a participant's recollection or a pain rating. A pain score and medication use are related but distinct outcomes. A score describes reported pain at a measurement time, while the medication quantity describes use of the patient-controlled analgesia system. Neither measure alone captures every aspect of postoperative pain or analgesia.

The timing matters to interpretation. The reported endpoint is a snapshot at 240 minutes after arrival in the recovery unit. It should not be read as total narcotic use across the full hospital stay or over later recovery. The registry does not report the endpoint at other time points as part of the posted primary outcome, nor does it report a definition of how missing measurements were handled.

7. Results Posted in the Registry

• Normal Saline: mean 3.70 versus 2.66 on control; difference 1.04 (95% CI -0.23 to 2.31), standardized effect d = 0.48; z-test p = 0.109.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Pain Score on a Scale of 1-10 (1=Least 10= Worst)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Normal Saline: mean 6.70 versus 3.60 on control; difference 3.10 (95% CI 1.40 to 4.80), standardized effect d = 1.07; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Normal Saline than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Heart Rate - Per Minute

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Normal Saline: mean 86.00 versus 70.00 on control; difference 16.00 (95% CI 8.32 to 23.68), standardized effect d = 1.24; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Normal Saline than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Oxygen Saturation - Measured in Percentage

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Normal Saline: mean 99.00 versus 97.00 on control; difference 2.00 (95% CI 0.83 to 3.17), standardized effect d = 1.00; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Normal Saline than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The secondary results offer a pattern that is directionally consistent across the three outcomes with posted numerical comparisons: the dexmedetomidine group has lower reported means for pain score and heart rate, and also a lower mean for oxygen saturation, at 240 minutes. The numerical comparisons and their individual uncertainty are displayed with the results. These are descriptive secondary findings, not substitutes for the primary endpoint, which measures narcotic quantity.

There is not a simple interpretation in which every secondary measure is another version of the primary outcome. Pain score reflects a rating, while heart rate and oxygen saturation are physiological measures. Their relationship to patient-controlled analgesia use is not established by these group summaries. The trial's primary comparison has a confidence interval that includes zero, while the posted secondary comparisons have intervals that exclude zero. That contrast does not resolve the primary result; instead, it emphasizes that outcomes can yield different estimates and levels of statistical evidence.

The registry names blood pressure and respiratory rate among the secondary outcomes, but numerical results for them are not reported in the registry record. The brief summary describes repeated measurements during recovery, while posted numerical secondary results are at 240 minutes. The available results therefore do not support a complete assessment of the full set of listed measures or time points.

Unadjusted secondary findings carry less weight as a group because several outcomes were considered and the registry record does not report how multiplicity was addressed. General explanation: when many tests are performed, the chance of at least one small p-value increases, even if the underlying effects are absent. Without a documented analysis plan or adjustment, each result can be described on its own, but the set should not be treated as a single confirmatory demonstration. The secondary data can suggest patterns for further study, but they do not establish the primary outcome's effect or its clinical importance.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Pain Score on a Scale of 1-10 (1=Least 10= Worst)
• Heart Rate - Per Minute
• Blood Pressure - Measured in mmHg
• Oxygen Saturation - Measured in Percentage
• Respiratory Rate as Measured Per Minute

9. Statistical Interpretation

10. Statistical Methods Explained

The results describe continuous outcomes using a mean and standard deviation for each group. A mean gives the average recorded value within a group. The standard deviation describes the spread of participant values around that average; it is not the uncertainty in the mean itself. For the primary outcome, the mean and standard deviation are reported for narcotic quantity in milligrams. Pain score and physiological measures are also summarized as means and standard deviations.

How to read a mean difference

The posted mean difference compares the normal saline group with the dexmedetomidine group, taking the normal saline mean minus the dexmedetomidine mean. A positive estimate therefore indicates a higher average in the normal saline group for the measure as coded. For narcotic quantity, the estimated difference is 1.04 mg. That direction is a description of the observed group summaries, not proof that the intervention caused a change. Randomization supports a group comparison, but the estimate remains subject to sampling variability and to limitations in the information recorded about trial conduct and analysis.

A confidence interval gives a range of values compatible with the data under the method used to calculate it. It is not a range containing a known fixed proportion of individual participant values, and it is not a guarantee that the true difference lies within the interval. For an unadjusted 95% confidence interval, exclusion of zero corresponds to evidence of a nonzero difference under the associated two-sided test at the conventional 0.05 level. The primary interval includes zero; the intervals for the three posted secondary comparisons exclude zero.

What the p-value says

A p-value describes how unusual data at least as discrepant as those observed would be if the null hypothesis of no group difference and the test assumptions were correct. It is not the probability that the null hypothesis is true, nor does it measure the size or clinical importance of a difference. The primary p-value is 0.109. The secondary p-values are each < 0.001. These are unadjusted comparisons, and the registry record does not report an analysis plan explaining how the full set of outcomes was handled.

The confidence intervals and p-values accompanying the comparisons are simple, unadjusted re-calculations from the posted group summary statistics. The registry record lists no reported analyses. These calculations therefore should not be mistaken for a detailed account of the investigators' planned model, covariate adjustment, or analytic population. The record does not report those details.

Why standard deviation and standard error differ

The standard deviation describes variation among participant measurements. A standard error describes uncertainty in an estimated statistic, such as a group mean, and depends on both the spread of the measurements and the amount of information available. General explanation: averaging more observations can make an estimate more precise even when individual observations remain variable. The registry includes group standard deviations, but information about participant-level data and missingness is not reported, so those summaries cannot reveal the full distribution or the presence of unusual values.

Why multiplicity matters

General explanation: testing multiple outcomes increases the chance that at least one comparison will appear statistically significant even when none of the underlying effects is real. A prespecified hierarchy, adjustment method, or clear distinction between confirmatory and exploratory outcomes can help readers judge the weight of multiple findings. The registry record does not report a multiplicity strategy. The unadjusted secondary p-values should consequently be interpreted as evidence for their individual comparisons, not as a family-wise conclusion across every outcome and time point.

Why over-dispersion matters

General explanation: a statistical model can understate uncertainty if it assumes less variability than the data actually contain. This is often discussed as over-dispersion, particularly for outcomes modeled as counts. The posted primary outcome is summarized as a continuous mean with a standard deviation, and the registry does not describe a count model or report an over-dispersion assessment. Accordingly, an over-dispersion adjustment cannot be attributed to this analysis from the registry record.

The record also does not describe whether analyses were based on intention-to-treat, per-protocol, or another population; how any missing outcomes were handled; whether assumptions were checked; or whether any baseline covariates were included. Those omissions limit reconstruction of the analysis. They do not change the arithmetic meaning of the posted means and comparisons, but they leave important aspects of the statistical procedure undocumented.

11. Confidence Intervals and Precision

Precision concerns how narrowly the data estimate a group difference. The primary 95% confidence interval runs from -0.232 to 2.312 mg for the normal saline minus dexmedetomidine comparison. Because the interval crosses zero, the data are compatible with no mean difference under the calculation used. They are also compatible with a modest difference in the opposite direction from the point estimate, or with a larger positive difference. The estimate of 1.04 mg is therefore not precise enough to settle the direction and magnitude of the primary contrast.

The interval should be read alongside the group means and standard deviations, rather than as a standalone verdict. The means are 2.66 mg and 3.7 mg, with standard deviations of 2.02 mg and 2.3 mg, respectively. Variation among participants is substantial relative to the estimated difference, and the outcome counts are 26 and 20. These registry entries help explain why a point estimate can be positive while its interval includes zero.

The secondary intervals are narrower in the sense that their reported bounds do not cross zero, but statistical separation from zero does not by itself establish importance to patients or clinical practice. The registry record does not report thresholds for a clinically meaningful difference, so clinical importance cannot be determined from statistical precision alone.

Confidence intervals also depend on the calculation and assumptions used. These are unadjusted re-calculations from summary statistics; detailed modeling choices and missing-data procedures are not reported in the registry record. The intervals describe uncertainty within those calculations, not every potential source of uncertainty about conduct, measurement, or generalizability.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size figures are planning illustrations based on the observed effect, not the trial's own design calculations. For these continuous outcomes, the listed figures are participants per arm, rather than total participants or total events. The planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The assumed effect to detect is the stated fraction of the observed effect. The registry record does not report the original sample-size justification or the trial's own design assumptions.

The 80% power column gives the planned participants per arm under the listed assumptions for an 80% chance of detecting the specified effect if that effect were the true one. The 90% power column describes the corresponding planning target for a 90% chance. Power in this setting is a property of a hypothetical design under assumptions; it is not a probability that the trial's observed finding is correct. These figures are not observed power.

Rows describing 100%, 75%, and 50% of the observed effect ask how the planning target changes if the effect to detect is the full observed estimate or a smaller portion of it. Smaller effects are harder to distinguish from random variation, so the illustrations require more participants per arm as the target effect becomes smaller. The displayed curve should be read as a visual representation of those planning relationships, not as evidence about the actual design or enrollment of this trial.

The planning illustrations do not account for details that are not reported in the registry record, such as a prespecified primary analysis model, participant loss, or a multiplicity strategy. They should not be used to infer that the completed trial was designed around the observed effects, or that a planned sample size guarantees a particular conclusion. They are conditional examples based on the stated assumptions and observed group summaries.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 1.040; pooled standard deviation σ = 2.145.
2. n = 2 × (1.96 + 0.842)² × 2.145² / 1.040² = 66.8, rounded up to 67 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 1.04                      # observed difference in means
sigma <- 2.1453967634746                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(2604940)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 67 (80% power), 90 (90% power)
 75% of observed effect: n per arm = 119 (80% power), 159 (90% power)
 50% of observed effect: n per arm = 268 (80% power), 358 (90% power)
power.t.test: 67.8 
Simulated power at n = 67 per arm: 0.796 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome and five secondary outcome measures. The brief summary describes repeated assessments during recovery, but numerical results in the registry are posted at 240 minutes for pain score, heart rate, and oxygen saturation. Results for blood pressure and respiratory rate are not reported in the registry record. The record gives no reported analyses for the secondary outcomes, and it does not describe a hierarchy for testing outcomes or a correction for multiple comparisons.

General explanation: multiplicity arises when researchers examine several outcomes, time points, subgroups, or analytic choices. If each is tested separately without adjustment, the chance of at least one apparently strong result can increase. A prespecified primary outcome can help keep interpretation focused, but readers still need to know whether secondary results were confirmatory, exploratory, or adjusted. That information is not reported in the registry record.

Missing-data handling is also not reported. The record does not say whether all randomized participants contributed to each endpoint, how unavailable measurements were treated, or whether any imputation or sensitivity analysis was used. Although the registry reports total enrollment and group-specific outcome counts, the reason for the different outcome counts is not reported in the registry record. It would be inappropriate to infer attrition, exclusions, or missing observations from these counts alone.

The analysis population is not reported in the registry record. In particular, it does not specify whether the results followed an intention-to-treat principle, included only participants with available outcomes, or used another population definition. The statistical model, any covariate adjustment, and assessment of model assumptions are also not reported. These gaps matter because they affect how fully the posted estimates can be reproduced and how confidently they can be linked to the randomized comparison.

Accordingly, the unadjusted comparisons can be read as calculations from the posted group summaries, but they do not fill the missing documentation about prespecification, multiplicity, missing data, or analysis populations. These issues are limitations in what can be concluded from the registry record, rather than evidence that any particular unreported procedure was or was not used.

15. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry reports zero serious adverse events and zero deaths in both groups. The serious adverse event counts are reported among 26 participants at risk in the dexmedetomidine group and 20 participants at risk in the normal saline group. The registry also reports zero other adverse events in each group, with the same group-specific counts at risk.

These figures describe what was recorded in the registry for this trial. They do not establish that no adverse events of any kind occurred outside the definitions or reporting period used for the posted results. The registry record does not report event terms, a detailed safety-monitoring plan, or the duration of safety follow-up. The list of serious adverse event terms is empty, consistent with the posted zero serious-event counts, but provides no additional event-level detail.

With the number of participants reported at risk, zero recorded events should be interpreted as an absence of reported events in this trial, not as proof that an event cannot occur. The figures also do not provide a precise estimate of comparative safety or establish the safety profile of either regimen beyond the information recorded for this study.

16. What the Result Does, and Does Not, Mean

The primary result is an estimate of the difference in mean narcotic quantity recorded at a specific time after surgery. The point estimate is higher in the normal saline group, but the 95% confidence interval includes zero and the unadjusted p-value is 0.109. The posted data therefore do not provide a statistically clear difference for the primary endpoint under the reported calculation. That is not the same as showing that the treatments have identical effects: the interval remains compatible with differences in either direction.

The trial addresses a focused question about one intraoperative dose and postoperative hydromorphone use in bariatric surgery patients. Its endpoint covers the period up to 240 minutes after arrival in the recovery unit. It does not establish the effect on total postoperative medication use, pain after that period, recovery after discharge, or outcomes in other populations. The registry record does not report a threshold for a difference that would be clinically important, so the clinical meaning of the estimated difference cannot be settled from the numerical results alone.

Secondary results show differences in pain score and physiological measurements at the posted time point, but they are unadjusted and the registry does not report a multiplicity plan. They should not be treated as a replacement for the primary result or as definitive evidence across all listed secondary outcomes. Numerical results for two listed secondary measures are not reported in the registry record.

Randomization and double masking describe the trial's design, but the registry does not report enough detail to evaluate sequence generation, masking implementation, missing-data handling, analysis populations, or the full statistical plan. These limits affect how comprehensively the findings can be assessed. The responsible interpretation is narrow: the registry records a primary mean difference with substantial uncertainty, plus several secondary comparisons that require cautious, exploratory reading.

17. Why This Trial Matters Statistically

This trial illustrates why statistical interpretation should not rely on the direction of a point estimate alone. The primary estimate favors lower recorded narcotic use in the dexmedetomidine group when expressed as normal saline minus dexmedetomidine, yet its confidence interval includes zero. The interval communicates that the data do not pin down the direction and size of the underlying difference with high precision. A headline focused only on the group means would miss that uncertainty.

It also illustrates the distinction between a primary endpoint and secondary outcomes. A trial can have a primary comparison that is inconclusive while some secondary comparisons appear statistically separated from zero. Those results are not necessarily contradictory: they measure different things and may have different variability. But multiple unadjusted comparisons need more cautious interpretation, particularly when the analysis plan is not reported.

The small outcome groups make the role of precision especially visible, while the planning illustrations show how sample-size requirements depend on the effect one aims to detect. Those illustrations are not the original trial plan and are not observed power. Keeping design assumptions separate from observed results helps prevent retrospective calculations from being mistaken for evidence that a study was adequately designed for a particular outcome.

Finally, the registry record demonstrates the value of reporting more than summary results. Information about participant flow, missing data, analysis populations, multiplicity, and the prespecified statistical approach would help readers determine how the reported estimates were produced and how broadly they can be interpreted. Where those details are absent, precise statistical description and clear limits are essential.

18. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The outcome is measured at 240 minutes after arrival in the post-anesthesia care unit. This bounded observation period does not describe narcotic use over the whole postoperative course. The brief summary mentions other recovery time points, but the posted numerical outcome results are limited to 240 minutes for the measures with available results. The registry record does not report a primary narcotic-use result for the other times.

The number of participants contributing to the reported primary groups is 26 and 20. The registry does not explain the group-count difference or report participant flow, exclusions, or missing measurements. Without that information, readers cannot determine whether all randomized participants were included in the comparison or whether outcome availability differed between groups.

There is no reported statistical analysis plan, sample-size justification, or analysis-population definition. Details of random-sequence generation, allocation concealment, and masking implementation are not reported in the registry record. The record also does not describe whether the analysis adjusted for baseline characteristics or how assumptions were assessed. These omissions limit evaluation of the conduct and reproducibility of the statistical analysis.

The secondary evidence is incomplete: numerical results are posted for three of the five listed secondary measures, and the registry does not describe multiplicity control. Several measurements are described in the summary, but only the 240-minute secondary results are posted for those three measures. Clinical thresholds for interpreting the size of group differences are not reported.

Finally, the results pertain to the population and perioperative setting described in the registry. The record does not provide participant characteristics sufficient to assess how well these findings represent other bariatric surgery populations or other clinical settings. The zero reported adverse-event counts also do not remove uncertainty about events beyond the study's reporting and follow-up.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Evaluation of Dexmedetomidine on Post-operative Narcotic Requirements and Pain Scores in Bariatric Patients — NCT02604940.
• Registry record last updated 2024-01-17; status last verified 2023-12.
• Results first posted 2024-01-17.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

22. Record Summary

This completed phase 4 study was a randomized, double-masked, parallel-group trial sponsored by West Virginia University. It enrolled 46 participants undergoing bariatric surgery, comparing a single intraoperative dexmedetomidine dose with normal saline. The primary endpoint was narcotic quantity delivered through patient-controlled analgesia at 240 minutes after arrival in the post-anesthesia care unit.

The posted primary means were 2.66 mg for dexmedetomidine and 3.7 mg for normal saline. The unadjusted mean difference was 1.04 mg, with a 95% confidence interval from -0.232 to 2.312 mg and p = 0.109. The interval includes zero, so the primary comparison is uncertain in direction and magnitude.

Three secondary outcomes have numerical results at 240 minutes; numerical results for blood pressure and respiratory rate are not reported in the registry record. No serious adverse events, other adverse events, or deaths were reported in either group. Details about the original sample-size justification, analysis populations, missing-data handling, and multiplicity procedures are not reported in the registry record.