Efficacy of Single-Shot Dexmedetomidine Versus Placebo in Preventing Pediatric Emergence Delirium in Strabismus Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy of Single-Shot Dexmedetomidine Versus Placebo in Preventing Pediatric Emergence Delirium in Strabismus Surgery (NCT01901588), a randomized phase 4 study. The primary outcome is Percentage of Patients Experiencing Pediatric Emergence Delirium in Strabismus Surgery.

2. Clinical Question

The clinical question is focused on an immediate post-operative event in a specific surgical setting and age range. It is not a general comparison of dexmedetomidine with placebo across different procedures or patient populations. The endpoint concerns whether emergence delirium was experienced during the stated observation period; the registry does not define additional criteria for deciding that an event occurred.

The comparison is randomized, so the intended interpretation is a between-group contrast under the trial’s allocation. The record identifies a parallel design and triple masking, but does not describe the randomization procedure or specify which people were masked. It also does not report the exact treatment timing beyond the pre-operative description, or other details that would clarify how the intervention was delivered. Those omissions limit reconstruction of the clinical procedures but do not change what the posted outcome itself records: the proportion of participants in each group recorded as experiencing emergence delirium during the PACU stay.

3. Trial Design

The registry describes a completed phase 4, randomized, triple-masked, parallel-group trial sponsored by NYU Langone Health. The study compares dexmedetomidine with placebo in pediatric participants undergoing strabismus surgery. The enrollment is 63. The registry gives a start of 2012-03 and primary completion of 2014-03. It does not report the original design rationale or the assumptions used to choose the planned enrollment.

The intervention is named dexmedetomidine, with the study summary also using the name Precedex. The comparator is placebo, described as saline solution. The summary says the intervention is used pre-operatively; details such as dose, route, and exact timing are not reported in the registry record. The record labels the study triple-masked but does not identify which roles were masked or explain how masking was maintained.

The primary endpoint is the percentage of participants experiencing pediatric emergence delirium during the length of the PACU stay, described as around 3 hours on average. The registry also lists secondary outcomes concerning pain medication, post-operative pain interventions, PONV rescue medication, time to arousal, and time to PACU discharge. Numerical results are posted for pain medication, PONV rescue medication, and time to arousal. The remaining listed secondary outcomes do not have numerical results in the posted results described in the registry record.

Several features needed to fully assess trial conduct are not reported in the registry record. These include the randomization method, the planned analysis population, the handling of missing outcome data, and the original statistical analysis plan. The record reports no analyses for the primary outcome and no reported analyses for the posted secondary outcomes, so the displayed comparisons should be understood as unadjusted recalculations from the posted group summaries rather than as a detailed account of the sponsor’s 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 Percentage of Patients Experiencing Pediatric Emergence Delirium in Strabismus Surgery, measured over Length of PACU stay (around 3 hours on average).

The primary endpoint is the percentage of participants experiencing pediatric emergence delirium during the PACU stay. It is a binary outcome: each participant is classified according to whether the event was recorded, and the group result expresses the share with an event. The registry describes the observation period as the length of PACU stay, around 3 hours on average. It does not give a more detailed event definition or explain how the assessment was made.

A percentage is useful for a binary endpoint because it describes the frequency of the recorded event within each treatment group. Comparing group percentages gives a direct summary of how often the event occurred under the trial’s two assigned approaches. The posted results are 50.0 for dexmedetomidine and 48.0 for placebo. These group summaries are descriptive; the risk-difference estimate and its confidence interval add information about the size and uncertainty of the between-group contrast.

The endpoint is specific to emergence delirium during the stated recovery period. It does not, by itself, describe pain, nausea, time to arousal, discharge timing, or longer-term outcomes. The registry does not report follow-up beyond the PACU timeframe for this endpoint, nor does it provide details about the instrument or threshold used to identify delirium. Those details matter when judging exactly what event the recorded percentage represents and how consistently it may have been assessed.

Because the measure is a percentage, the reported values should be read as group-level event frequencies rather than as a continuous measure of symptom severity. The endpoint does not indicate the duration or intensity of an event. Its clinical interpretation therefore depends on the event definition and assessment procedures, which are not reported in the registry record.

7. Results Posted in the Registry

• Dexmedetomidine: 50.0% (13/26) versus 48.3% (14/29) on control; risk difference 1.7 percentage points (95% CI -24.7 to 28.2), risk ratio 1.04 (0.60–1.77); unadjusted two-proportion z-test p = 0.898.

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.

Percentage of Participants Receiving Pain Medication

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Dexmedetomidine: 50.0% (13/26) versus 65.5% (19/29) on control; risk difference -15.5 percentage points (95% CI -41.4 to 10.3), risk ratio 0.76 (0.48–1.22); unadjusted two-proportion z-test p = 0.244.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Dexmedetomidine and the control. The interval gives the range of effects that remain compatible with the data.

Percentage of Participants Requiring Post-operative Nausea and Vomiting (PONV) Rescue Medications

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Dexmedetomidine: 0.0% (0/26) versus 13.8% (4/29) on control; risk difference -13.8 percentage points (95% CI -26.3 to -1.2); unadjusted two-proportion z-test p = 0.049.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically lower for Dexmedetomidine than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Time to Arousal

• 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:
  • Dexmedetomidine: mean 60.00 versus 40.00 on control; difference 20.00 (95% CI 0.18 to 39.82), standardized effect d = 0.53; z-test p = 0.048.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Dexmedetomidine than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The posted secondary outcomes cover pain medication, PONV rescue medication, and time to arousal, alongside additional outcomes listed in the registry concerning post-operative pain interventions and PACU discharge. The reported numerical findings do not form a single uniform pattern: the point estimates and uncertainty differ across endpoint types. They should be treated as separate descriptive comparisons rather than as a unified confirmation of the primary result.

The primary endpoint concerns emergence delirium, while the secondary measures address other aspects of recovery. A result on a secondary outcome does not establish the primary endpoint’s effect, and the primary result does not determine what happened on those other measures. Together, the outcomes can provide context about post-operative recovery, but they do not substitute for one another. The registry does not report a joint analysis linking the secondary outcomes to emergence delirium.

The posted secondary p-values are unadjusted. When several outcomes are examined, the chance of observing at least one apparently notable result by chance can increase. Without a reported multiplicity strategy, isolated secondary p-values carry less weight than a prespecified primary comparison and should be interpreted cautiously. The registry does not report a hierarchy or correction procedure for these outcomes.

Some secondary endpoints are binary and others are continuous, so their estimates are expressed on different scales and are not directly interchangeable. The record also lists outcomes for which numerical results are not posted in the material described by the registry record. Missing numerical results are not evidence of no effect or no events. The secondary results are best used as exploratory context, with attention to their uncertainty, the lack of reported multiplicity adjustment, and the absence of a detailed analysis plan.

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

• Percentage of Participants Receiving Pain Medication
• Post-op Pain Interventions
• Percentage of Participants Requiring Post-operative Nausea and Vomiting (PONV) Rescue Medications
• Time to Arousal
• Time to PACU Discharge

9. Statistical Interpretation

10. Statistical Methods Explained

Several statistical ideas help interpret the posted comparison. The primary outcome is binary: a participant either had recorded emergence delirium during the specified period or did not. The group percentage is the observed frequency of that event. It gives a straightforward description, but a percentage alone does not quantify uncertainty about the contrast between groups.

What does the risk difference describe?

The risk difference compares the event proportion in the dexmedetomidine group with the event proportion in the placebo group. A value at zero represents no difference on this scale. Positive and negative values indicate different directions according to the group ordering used for the comparison. Unlike a relative measure, the risk difference is an absolute contrast: it describes the separation between the two proportions rather than how many times one proportion is the other. The posted estimate is 0.017. Its confidence interval runs from -0.247 to 0.282, spanning zero and extending in both directions.

The registry also gives group-level event counts in the recalculation inputs: 13 of 26 for dexmedetomidine and 14 of 29 for placebo. Those counts correspond to the posted percentages of 50.0 and 48.0. They are useful for understanding how the group percentages arise, but the registry does not explain why the endpoint denominators differ from the enrollment figure. They should not be used to infer the reason for missing or excluded observations.

How should the confidence interval be read?

A confidence interval expresses uncertainty around an estimated effect under the calculation method. It is not a range in which every value is equally likely, and it does not guarantee that the true effect lies within its limits. For this comparison, the interval includes zero and values on either side. The interval’s breadth indicates that the estimate does not pin down the effect narrowly. The registry does not report a confidence level for the posted recalculation, so none should be assumed from the record.

The p-value of 0.898 is an unadjusted measure of how incompatible the observed comparison is with a no-difference reference under the statistical test used for recalculation. It is not the probability that the null hypothesis is true, and it does not measure the probability that the result will replicate. A large p-value does not establish equality. The interval and the group summaries provide the context needed to understand what effect sizes remain plausible under the calculation.

What does unadjusted mean?

An unadjusted comparison is based on the posted summary data without accounting for additional covariates or other design features through an adjusted model. The registry record does not report a sponsor analysis for the primary outcome or a detailed statistical analysis plan. The recalculated comparison should therefore be distinguished from an adjusted estimate or a complete sponsor analysis. There is no discrepancy flag, but that does not supply details that are absent from the record.

For binary outcomes, a risk difference is only one useful summary. Relative measures can express a ratio of event frequencies, but they answer a different question and may be harder to interpret when event counts are limited. The posted primary comparison includes risk-ratio and odds-ratio calculations as well, but the absolute risk difference is directly tied to the between-group percentage contrast. None of these measures removes uncertainty or compensates for limitations in the outcome definition and data completeness.

Why do event counts matter?

With a binary endpoint, information about the comparison depends in part on how many events and non-events are observed, as well as the group sizes. When counts are limited, changing the classification of a small number of participants can have a noticeable influence on the estimated proportions. The registry does not report a separate sensitivity analysis for alternative event classifications or missing observations. Consequently, the point estimate should be viewed alongside its interval and the limitations of the recorded outcome information.

General statistical context: when an outcome is binary, the variance of a proportion depends on the event probability, so the precision is not determined by a group’s size alone. For other kinds of outcomes, such as counts with over-dispersion, a model that accounts for variability beyond a simple distributional assumption may be important. That issue is not directly applicable to this primary binary endpoint, and the registry does not report an over-dispersion model or any such analysis. For the continuous secondary endpoint of time to arousal, the posted summaries use means and standard deviations, but the registry does not state whether a particular modeling assumption was checked.

The registry’s classification of a trial as randomized supports interpreting the comparison as an assigned-group contrast, but the record does not describe allocation concealment, randomization details, adherence, or participant flow. Triple masking is reported, though the identities of the masked roles are not. These design features affect how confidently one can attribute a group difference to the assigned intervention; their unreported details should not be filled in by assumption.

11. Confidence Intervals and Precision

The primary confidence interval is -0.247 to 0.282 for a risk-difference estimate of 0.017. Since zero is included, the interval does not exclude no difference under the recalculation. The negative and positive limits also allow for effects in either direction. Its width signals limited precision: the point estimate is close to zero, but the data do not narrow the range of compatible contrasts to values close to that estimate.

Precision is distinct from statistical significance. The p-value of 0.898 is consistent with the interval’s inclusion of zero, but the interval shows more than whether a conventional threshold is crossed: it displays the range of effect estimates compatible with the method and posted data. Here, that range includes a potentially lower event proportion with dexmedetomidine and a potentially higher one. The registry does not report a prespecified threshold for what difference would be clinically important, so the interval cannot be classified against a trial-defined meaningful-effect boundary.

Confidence intervals also do not account for every uncertainty in a trial. They reflect sampling uncertainty under the calculation used, but do not resolve questions about endpoint definition, missing data, analysis populations, masking procedures, or other design details that are not reported in the registry record. The endpoint denominator is 26 for dexmedetomidine and 29 for placebo, while enrollment is 63; the reason for that difference is not given. This makes the documented data flow an additional consideration beyond the interval itself.

In practical terms, the primary estimate is not precise enough to support a narrow claim about the size or direction of the contrast. It is more accurate to say that the observed percentages are similar and that the interval remains compatible with a range of effects, including zero. A confidence interval should be read as an uncertainty statement, not as proof that the result is clinically unimportant or that no difference exists.

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 original design. For the primary binary endpoint and the posted secondary comparisons that include planning figures, the entries are participants per arm. They are not total events. The registry’s planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; each planning scenario uses the stated fraction of the observed effect. The trial’s own original design assumptions are not reported in the registry record.

The 80% power column gives the illustrative number of participants per arm under which the stated effect would be detected in 80% of repeated studies, if the planning assumptions and effect were correct. The 90% power column uses a higher probability of detecting that effect, which requires more participants per arm. For the primary endpoint, the entries are 13,197 for 80% power and 17,667 for 90% power when planning for 100% of the observed effect; the values rise to 23,458 and 31,403 for 75% of the observed effect, and 52,771 and 70,645 for 50% of the observed effect.

Smaller effects are harder to distinguish from random variation, so planning for a smaller fraction of the observed effect requires more participants. These figures are not observed power and do not show the probability that the completed trial’s conclusion is correct. They are conditional planning calculations, and their size is sensitive to the effect chosen as the target. The observed primary estimate is uncertain, so using it as a planning anchor should not be mistaken for a reliable forecast of the effect in a future study.

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, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.483; treatment proportion p₁ = 0.500; average p̄ = 0.491.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.7070 = 1.3857.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.7069 = 0.5949.
4. n = (1.3857 + 0.5949)² / (0.0172)² = 13,196.7, rounded up to 13,197 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
p0 <- 0.482758620689655                          # control proportion
p1 <- 0.5                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^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 (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(1901588)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 13,197 (80% power), 17,667 (90% power)
 75% of observed effect: n per arm = 23,458 (80% power), 31,403 (90% power)
 50% of observed effect: n per arm = 52,771 (80% power), 70,645 (90% power)
power.prop.test: 13196.7 
Simulated power at n = 13,197 per arm: 0.801 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-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 lists a primary endpoint and several secondary outcomes, but does not report a multiplicity adjustment or a hierarchy specifying how those outcomes were to be interpreted. This matters because evaluating multiple outcomes creates multiple opportunities for apparently notable findings. An unadjusted p-value for a secondary outcome does not account for the fact that other outcomes were also examined. The unadjusted results can be informative as exploratory evidence, but should not be treated as definitive confirmation without a reported prespecified strategy.

The primary comparison has an unadjusted p-value of 0.898, and the registry does not report a sponsor analysis or a detailed statistical analysis plan for it. The posted secondary comparisons also have no reported analyses. It is therefore not possible to establish from the registry record which model, testing sequence, or adjustment procedure was specified before results were examined. The record does not report whether any interim analyses were planned or conducted.

Missing-data handling is also not reported. The primary endpoint summaries give 26 participants for dexmedetomidine and 29 for placebo, while enrollment is 63. The registry does not explain the difference, state whether any outcomes were missing, or describe an imputation or sensitivity method. The appropriate analysis population—such as an intention-to-treat population or another defined group—is not reported in the registry record. It is not possible to infer the reasons for the denominators or whether exclusions affected the comparison.

These omissions limit reproducibility and make it harder to assess whether the posted calculations follow the trial’s intended plan. Randomization and masking are recorded, but the randomization procedure and masked roles are not described. The record also does not describe adherence or participant flow. These are reporting limitations, not proof that the trial procedures were inadequate. They do mean that the posted unadjusted summaries should be interpreted as limited evidence rather than as a complete account of the planned analysis.

15. Safety Results

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

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 other adverse events for the dexmedetomidine group, with 32 at risk for each category. For placebo, it reports zero serious adverse events and zero other adverse events, with 31 at risk for each category. These figures describe the adverse-event summaries as entered in the registry; they do not establish that no adverse effects of any kind occurred or that the groups have identical safety profiles.

The death counts are null for both groups, so deaths are not reported in the registry record. The adverse-event at-risk counts differ from the primary endpoint denominators, and the record does not explain that difference. It also does not provide event descriptions for other adverse events, because none are listed as affecting participants in the posted summary. Interpretation is therefore limited to the reported categories, counts, and at-risk groups. The registry does not provide enough detail to assess event ascertainment, follow-up completeness, or rare events beyond these summaries.

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

The posted primary data show similar group percentages for emergence delirium during the PACU stay: 50.0 for dexmedetomidine and 48.0 for placebo. The unadjusted risk difference is 0.017, and its confidence interval ranges from -0.247 to 0.282. The interval crosses zero and permits effects in either direction. The unadjusted p-value is 0.898. Taken together, these results do not show a statistically detectable difference in this comparison, but they do not demonstrate that the treatments are equivalent or that the true effect is zero.

The result does not establish that dexmedetomidine prevents emergence delirium, nor does it establish that it cannot affect the outcome. The observed percentages are estimates from the recorded endpoint data, and the interval remains broad. The registry does not report an equivalence margin, a clinically important difference threshold, or a sponsor-reported analysis that would support a stronger conclusion. The appropriate interpretation is limited to the comparison and observation period recorded in the trial.

The findings apply to the registry’s described population of children ages 1-7 undergoing strabismus surgery and to the PACU observation period, around 3 hours on average. They should not automatically be extended to other age groups, procedures, settings, or follow-up periods. The precise event definition and assessment method are not reported in the registry record, which further limits how specifically the endpoint can be interpreted.

Secondary results address other recovery outcomes and do not replace the primary comparison. Because the registry does not report a multiplicity strategy, unadjusted secondary findings are less secure as confirmatory evidence. The adverse-event summary reports no affected participants in the listed serious or other categories, but deaths are not reported and the event reporting details are limited. The record therefore offers a narrow view of the results rather than a complete account of all possible benefits, harms, or longer-term outcomes.

Overall, the posted results are inconclusive about the size and direction of the primary contrast. Similar observed percentages are a description of the trial data, not proof of no effect. The confidence interval is central to that distinction: it retains uncertainty about effects that could be lower or higher than the observed estimate.

17. Why This Trial Matters Statistically

This trial illustrates why a point estimate and a p-value are not enough to characterize a clinical comparison. The primary percentages are close, and the p-value is large, but the confidence interval is broad and includes effects in both directions. Reading the interval alongside the estimate avoids turning a failure to detect a difference into a claim that the treatments are the same.

It also shows how endpoint denominators and enrollment should be kept distinct. Enrollment is 63, while the primary outcome summaries use 26 and 29 participants in the respective groups. The record does not explain the difference. Without participant-flow details or a stated analysis population, readers cannot determine from the registry why those denominators appear or how missing information was handled. This is a reporting issue with direct consequences for interpreting precision and reproducibility.

The study’s multiple recovery outcomes demonstrate why secondary findings need a different evidential weight from a prespecified primary comparison. The registry does not report a multiplicity plan or detailed analysis plan, and the secondary p-values are unadjusted. A statistically notable result among multiple outcomes can be less convincing when the testing strategy is unknown. The secondary measures can still provide context, but should not be read as a set of independent confirmations.

Finally, the record separates what is known from what remains unspecified. Randomization, triple masking, the parallel design, and the intervention comparison are recorded, while procedural details and analysis choices are not. Transparent interpretation requires preserving both sides: use the posted evidence, but avoid filling gaps with assumptions. That discipline is especially important when estimates are imprecise and registry reporting does not fully document trial conduct.

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.
• Participant counts were reconstructed from posted percentages and arm sizes, so small rounding differences are possible.

The primary outcome definition is brief. The registry identifies the endpoint as the percentage experiencing pediatric emergence delirium during the length of the PACU stay, around 3 hours on average, but does not report a detailed diagnostic threshold, assessment instrument, assessor role, or timing of assessments. Those details could affect which events are counted and how comparable the observations are across groups.

The primary outcome denominators are 26 for dexmedetomidine and 29 for placebo, while enrollment is 63. The registry does not explain the difference or report participant flow, missing-data handling, or the analysis population. This prevents readers from determining whether the summaries represent all randomized participants or a subset and whether any missingness could affect the results.

Important intervention and design details are also absent. The record describes a pre-operative single-shot intervention, but does not report dose, route, exact administration timing, or adherence. It states triple masking without identifying the masked roles. The randomization method and allocation procedures are not reported. These limitations restrict assessment of how the intervention and masking were implemented.

The registry does not report a detailed statistical analysis plan, a sponsor-reported primary analysis, an interim-analysis plan, or multiplicity handling. The posted primary comparison is an unadjusted recalculation from summary statistics. Secondary numerical results are not posted for every outcome named in the registry, and deaths are not reported in the adverse-event summary. These reporting gaps do not establish that trial procedures were deficient, but they limit independent evaluation of the analysis and the completeness of outcome reporting.

Finally, the primary follow-up is limited to the PACU stay as described. The registry does not report longer-term outcome data for emergence delirium. The result should therefore be understood as a comparison of the recorded short-term endpoint in this particular surgical population, not as an assessment of broader or later outcomes.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Efficacy of Single-Shot Dexmedetomidine Versus Placebo in Preventing Pediatric Emergence Delirium in Strabismus Surgery — NCT01901588.
• Registry record last updated 2016-07-11; status last verified 2016-06.
• Results first posted 2016-03-08.
• 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

The registry describes a completed phase 4, randomized, triple-masked, parallel trial sponsored by NYU Langone Health. It compares single-shot pre-operative dexmedetomidine with saline placebo in children ages 1-7 undergoing strabismus surgery. Enrollment is 63; the recorded start is 2012-03 and primary completion is 2014-03.

The primary endpoint is the percentage experiencing emergence delirium during the PACU stay, around 3 hours on average. Posted percentages are 50.0 for dexmedetomidine and 48.0 for placebo. The unadjusted risk-difference estimate is 0.017, with a confidence interval from -0.247 to 0.282 and p = 0.898. The estimate is imprecise and does not establish a difference or equivalence.

The registry does not report the original design assumptions, detailed analysis plan, missing-data methods, or analysis population. Secondary findings and adverse-event summaries have limitations, including unadjusted comparisons and unreported death counts.