This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Dexmedetomidine as a Rapid Bolus in Children for Emergence Agitation (NCT01528891), a randomized phase 3 study. The primary outcome is Heart Rate (HR).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01528891 |
| Phase | Phase 3 |
| Condition | Tonsillectomy |
| Allocation | Randomized |
| Design model | Single Group |
| Masking | Quadruple |
| Enrollment | 418 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Peter Davis |
| Results posted | Yes |
2. Clinical Question
Population
The clinical context is anesthetized children undergoing tonsillectomy. The registry record describes the study as examining emergence agitation in children and identifies tonsillectomy as the condition. It does not report additional eligibility details, such as age limits, clinical exclusions, or the setting in which participants were recruited. Those details are not reported in the registry record, so the population cannot be characterized more narrowly from this information.
Intervention
The intervention was dexmedetomidine, described in the title and summary as a rapid bolus injection. The registry record identifies dexmedetomidine as a drug intervention. It does not report the dose, concentration, injection rate, or other administration details in the available intervention description. These specifics are not reported in the registry record.
Comparator
The comparator was placebo, described in the arm information as normal saline. The record lists randomized allocation and identifies dexmedetomidine and placebo interventions. It does not provide further details about preparation, administration, or whether the placebo was matched in every respect. Those details are not reported in the registry record.
Primary question
The primary outcome was heart rate, measured in beats per minute. The stated question was whether heart rate differed between groups at each measurement time and changed within groups over time. The registry also identifies emergence agitation as a secondary outcome and describes the study as assessing the cardiovascular profile of a rapid dexmedetomidine bolus. Numerical heart-rate results and numerical emergence-agitation results are not reported in the registry record.
In statistical terms, the clinical question has more than one dimension. It concerns a between-group comparison at repeated time points, as well as changes over time within each group. Those are related but not interchangeable questions: a change within one group does not by itself establish a difference between groups. The record’s stated comparison structure is important when interpreting any reported estimates. Because the numerical results are not reported in the registry record, the direction, size, and precision of any heart-rate difference cannot be assessed from this record. Nor can the listed secondary outcome establish whether emergence agitation differed between groups.
3. Trial Design
The registry identifies this as a phase 3 randomized trial with quadruple masking. The listed interventions are dexmedetomidine and placebo, with normal saline described for the placebo arm. The study status is completed, and enrollment is recorded as 418. Its start is listed as 2012-01, and primary completion as 2014-08. The record identifies Peter Davis as the sponsor.
There is an internal design-description inconsistency: allocation is recorded as randomized, while the model is recorded as single group. These entries do not provide a coherent, complete account of the trial structure. The listed interventions and arm descriptions indicate that the record contains treatment-group information, but the single-group model designation should not be silently replaced with a different design label. The reason for the discrepancy is not reported in the registry record.
Quadruple masking indicates that the registry uses that masking designation, but the record does not spell out which roles were masked or how masking was maintained. It also does not report the randomization sequence method, allocation concealment procedures, or whether treatment assignments were stratified. Those details are not reported in the registry record.
The primary outcome is heart rate, a continuous measure reported as a mean with standard deviation. Measurements were planned immediately before study drug injection, every minute thereafter for 5 minutes, and upon arrival in the Post-Anesthesia Care Unit. The record states that comparisons were made between groups at each time point and within groups over time. It lists emergence agitation as a secondary outcome. The specific statistical models and methods used for these comparisons are not reported in the registry record.
The completed status and enrollment entry describe the registered study, not the completeness of the outcome data or the number analyzed for each endpoint. The registry record does not report the analyzed population, missing outcome counts, or a flow of participants through the trial. Those details are not reported in the registry record.
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.
Before assignment: 418 patients overall were enrolled in the study. Of these patients, 18 failed screening prior to randomization into either treatment arm.
Overall Study
| Stage | Dexmedetomidine | Placebo |
|---|---|---|
| STARTED | 200 | 200 |
| COMPLETED | 200 | 200 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Heart rate values were compared between groups at each time point and within groups over time.
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.
| Characteristic | Unit | Dexmedetomidine | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 195 | 198 | 393 | |
| Age, Categorical: <=18 years | Participants | 195 | 198 | 393 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 0 | 0 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Continuous | years | 6.1 (SD 1.6) | 5.8 (SD 1.6) | 6.0 (SD 1.6) |
| Sex: Female, Male: Female | Participants | 96 | 97 | 193 |
| Sex: Female, Male: Male | Participants | 99 | 101 | 200 |
| Region of Enrollment: United States | participants | 195 | 198 | 393 |
6. Primary Endpoint
The registry lists the primary outcome as Heart Rate (HR), measured over Heart rate was measured immediately prior to study drug injection (baseline) and every minute thereafter for 5 minutes. Heart rate was also measured upon the patient's arrival to the Post-Anesthesia Care Unit (PACU)..
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | bpm |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is heart rate, expressed in beats per minute. Heart rate is a continuous cardiovascular measure, and the record says it was summarized as a mean with standard deviation. It was measured at baseline, repeatedly after study-drug injection, and upon arrival in the Post-Anesthesia Care Unit. The registry describes both between-group comparisons at each time point and within-group change over time.
Repeated measurements can help describe the course of a continuous measure rather than restricting attention to a single observation. A baseline measurement gives a reference point, while subsequent measurements describe the recorded pattern after injection. A comparison between groups at a given time point asks whether their observed heart rates differ at that time. A within-group comparison asks how measurements change over time among participants in that group. These questions should not be conflated: a change over time in one group alone does not show that the groups differ.
Heart rate is relevant to the trial’s stated interest in the cardiovascular profile of a rapid bolus. However, a measure’s clinical relevance does not supply its numerical result or establish the meaning of any difference. The registry record does not report the heart-rate means, standard deviations, estimated group contrasts, confidence intervals, or significance tests. It also does not report a single prespecified time point as the sole primary comparison. The primary-outcome description lists multiple measurement times and types of comparison, so the results cannot be reduced to one numerical contrast from the information reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The available registry information establishes the trial’s stated design features and outcome structure, but it does not provide numerical findings for the primary heart-rate endpoint. Although the record identifies heart rate as the primary outcome and describes how it was measured, it does not report group means, standard deviations, between-group estimates, confidence intervals, or p-values. The direction and magnitude of any observed difference, and the precision with which it was estimated, are therefore not reported in the registry record.
The registry lists emergence agitation as a secondary outcome, but gives no numerical result for its incidence. The study’s title and summary indicate that emergence agitation was a subject of interest; that purpose does not establish what the observed incidence was or whether it differed between groups. Without results, it is not possible to characterize the effect estimate for either the primary or secondary outcome.
The outcome description involves measurements at multiple time points, between-group comparisons at each time point, and within-group comparisons over time. Each comparison would answer a somewhat different question. A group’s change from baseline, for example, is not equivalent to a contrast between groups at a particular time. Interpreting any such findings would require the estimates, their uncertainty, and sufficient detail about the analysis. These numerical results and analytic details are not reported in the registry record.
The record includes safety counts as well as the primary outcome description. For serious adverse events, it records 1 affected participant in the dexmedetomidine group and 0 in the placebo group, with 200 at risk in each group. It separately lists other adverse events, with 18 affected in the dexmedetomidine group and 34 in the placebo group, also with 200 at risk in each group. These are registry-recorded counts, not a substitute for the missing efficacy results. The record does not report deaths, and their values are not reported in the registry record.
Enrollment is listed as 418, but that figure alone does not establish how many participants contributed data to each outcome, whether all randomized participants were analyzed, or how missing observations were handled. Those matters are not reported in the registry record. The record’s completed status likewise does not establish that every planned analysis was completed or that all results were posted.
Consequently, interpretation should remain descriptive: the registry identifies a randomized, quadruple-masked study and its intended outcomes, but does not report the numerical primary or secondary outcome findings needed to judge effect size or precision. No conclusion about the direction or size of an outcome difference can be drawn from the outcome descriptions alone.
9. Statistical Methods Explained
The primary outcome is continuous: heart rate, measured in beats per minute. The registry says it was characterized by a mean and standard deviation. These statistics provide different information. A mean describes the center of the observed measurements, while a standard deviation describes their spread around that center. A mean difference between groups, if reported, would describe the contrast in average heart rate on the measurement scale. Neither a mean nor a standard deviation alone describes the uncertainty in a group comparison.
What would a confidence interval add?
In general, a confidence interval expresses the statistical uncertainty around an estimated quantity. For a group contrast, it would help show which values are reasonably compatible with the observed data under the analysis assumptions. A narrow interval indicates more precision than a wide interval. The interval would need to be interpreted in relation to the outcome scale and the clinical question; its width does not, by itself, establish clinical importance. The registry record does not report confidence intervals for the primary outcome, so the precision of the heart-rate comparisons is not reported in the registry record.
How do repeated measurements affect interpretation?
The record describes heart-rate measurement before injection, every minute for 5 minutes afterward, and on arrival in the Post-Anesthesia Care Unit. These observations are repeated measurements on participants, not a collection of unrelated outcomes by default. In general, measurements from the same participant may be correlated: a participant’s value at one time can be related to that participant’s value at another time. Statistical methods for repeated measurements can account for that dependence, whereas treating every observation as independent may misrepresent uncertainty. The registry record describes comparisons between groups at each time and within groups over time, but does not report the model or method used to handle within-participant dependence.
There are several possible ways to present repeated-measure data, and they need not answer precisely the same question. Separate comparisons at each time focus on group contrasts at those times. A model for the trajectory can instead describe how the pattern evolves across time and may estimate a group-by-time relationship. Baseline adjustment may also affect the interpretation of later comparisons. These are general methodological distinctions, not claims about which analysis was performed in this trial. The analysis method and any baseline adjustment are not reported in the registry record.
Why does multiplicity matter?
In general, multiple statistical tests create more opportunities to observe a nominally unusual result by chance. That issue can arise when a study tests multiple time points, multiple outcomes, or several contrasts. Approaches to multiplicity may adjust the interpretation or control error rates across a defined family of tests. The appropriate approach depends on which comparisons were planned and how the primary question was specified. The registry describes multiple time points and comparisons but does not report a multiplicity strategy. It is therefore not possible to determine from the registry record whether or how multiplicity was addressed.
What does over-dispersion mean?
Over-dispersion is a general concern for some count outcomes when observed variability exceeds what a chosen statistical model assumes. It is not automatically relevant to every outcome: heart rate is recorded as a continuous measure, while the secondary outcome of emergence agitation is described as an incidence. If event counts are analyzed, a model that assumes less variability than the data contain can produce uncertainty estimates that are too small. A suitable method depends on the outcome distribution and analysis plan. The registry record does not report the statistical model for emergence agitation or whether over-dispersion was assessed.
How should planning calculations be read?
The sample-size illustrations are described as planning calculations based on fractions of the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. They are not the trial’s own design justification, and they should be read as hypothetical planning quantities rather than evidence about what the trial was powered to detect. For outcomes other than time-to-event measures, the stated convention is participants per arm; time-to-event illustrations instead concern a total event count. The record does not report the trial’s sample-size justification or state that these planning calculations were used to design the trial. They are not observed power. The numerical observed effect underlying the illustrations is not reported in the registry record alongside the primary endpoint description.
More broadly, the statistical analysis plan is not reported in the registry record. The record reports that 10 analyses are listed, but the number alone does not describe their methods, hierarchy, or role in the analysis. It also lists 4 outcome measures without supplying numerical primary heart-rate results. No model specification, standard-error method, adjustment strategy, or analysis population can be inferred from those counts. Any detailed account of methods actually used would require information not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome is measured at several time points, and the registry describes comparisons between groups at each time point as well as comparisons within groups over time. It also lists emergence agitation as a secondary outcome. This structure raises general multiplicity questions because conclusions may depend on which times, outcomes, and contrasts are treated as confirmatory. The registry record does not report whether a particular time point was designated as the principal comparison, how the family of tests was defined, or whether any multiplicity adjustment was planned or used.
Missing-data handling is also not reported in the registry record. There is no account of missing heart-rate observations, reasons for missingness, or the method used to handle incomplete repeated measurements. The record does not state whether participants were analyzed according to randomized assignment or according to another analysis population. Enrollment is reported as 418, but an enrollment figure does not establish the number contributing data to any specific analysis.
The registry indicates that 10 analyses are listed, but does not give enough information to determine their relationship to the primary and secondary outcomes or whether they were prespecified. The statistical analysis plan, including any rules for exclusions, covariate adjustment, or sensitivity analyses, is not reported in the registry record. As a result, the extent to which the analysis addresses multiplicity or missingness cannot be assessed from these entries.
These omissions limit interpretation of both statistical significance and precision. They do not establish that the trial had no analysis plan or that data were missing; they mean those details are not reported in the registry record.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Dexmedetomidine | 1 | 200 | 0.5% |
| Placebo | 0 | 200 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Dexmedetomidine | 18 of 200 |
| Placebo | 34 of 200 |
Most frequent serious adverse event terms
| Event term | Organ system | Dexmedetomidine | Placebo |
|---|---|---|---|
| Desaturation with Atelectasis | Respiratory, thoracic and mediastinal disorders | 1 of 200 | 0 of 200 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Dexmedetomidine | Placebo |
|---|---|---|---|
| Bleeding | General disorders | 4 of 200 | 9 of 200 |
| Laryngospasm | General disorders | 0 of 200 | 7 of 200 |
| Desaturation | General disorders | 1 of 200 | 5 of 200 |
| Emesis | General disorders | 3 of 200 | 2 of 200 |
| Stridor | General disorders | 1 of 200 | 3 of 200 |
| Croupy Cough | General disorders | 1 of 200 | 3 of 200 |
| Nausea | General disorders | 1 of 200 | 3 of 200 |
| Headache | General disorders | 1 of 200 | 2 of 200 |
| Congestion | General disorders | 3 of 200 | 0 of 200 |
| Enuresis | General disorders | 2 of 200 | 1 of 200 |
Serious events with the highest arm-level rate: desaturation with atelectasis (0.5%).
The registry records serious adverse events separately from other adverse events. For serious adverse events, the dexmedetomidine group has 1 affected participant among 200 at risk, while the placebo group has 0 among 200 at risk. The listed serious-event term is Desaturation with Atelectasis, recorded as 0.5%. The record does not provide further detail about severity, timing, relatedness to treatment, or event adjudication.
For other adverse events, the record lists 18 affected participants in the dexmedetomidine group and 34 in the placebo group, with 200 at risk in each group. These counts should not be combined with the serious-event counts: the registry presents them as separate categories, and it does not explain whether categories could overlap or how events were classified. The figures are descriptive registry entries, not adjusted comparisons. No uncertainty estimates or formal between-group safety analysis are reported in the registry record.
Deaths are listed with no numeric value. That is not the same as reporting zero deaths; deaths are not reported in the registry record. The counts also do not, by themselves, establish causation or the overall safety profile. Details needed to interpret event collection, follow-up, and treatment attribution are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The record identifies a randomized, quadruple-masked phase 3 study comparing dexmedetomidine with placebo in anesthetized children, with heart rate as the primary outcome and emergence agitation as a secondary outcome. It also describes the timing of heart-rate measurements and provides adverse-event counts. Those entries clarify what the study set out to examine and what types of data the registry records.
They do not establish the numerical effect of dexmedetomidine on heart rate or emergence agitation. The registry record does not report the primary heart-rate results or numerical results for emergence agitation. Without estimates and uncertainty measures, the size, direction, and precision of those outcome contrasts cannot be described. The stated objectives are not findings, and a completed study status does not itself provide evidence about the outcomes.
The adverse-event counts have a narrower meaning: they are the numbers recorded in the registry under the serious and other adverse-event categories, alongside the listed at-risk counts. They do not provide an adjusted comparison, establish causality, or resolve the missing efficacy results. Deaths are not reported in the registry record.
The record’s design entries also warrant care because randomization is listed while the model is designated single group. The reason for that inconsistency is not reported in the registry record. Other important details—including missing-data procedures, analysis populations, and multiplicity handling—are likewise not reported. Thus the registry can support a description of the registered study and its recorded safety counts, but not a numerical judgment about the primary or secondary outcome effects.
These limits do not mean that the study found no difference, nor do they mean that a difference was present. The outcome results necessary to distinguish those possibilities are not reported in the registry record. Statistical interpretation should not substitute an assumption for the missing estimates.
13. Why This Trial Matters Statistically
This study illustrates why a trial’s registered question and its posted numerical results are both needed for statistical interpretation. The registry gives a recognizable clinical focus: heart rate after a rapid dexmedetomidine bolus, measured repeatedly in anesthetized children, with emergence agitation also listed as an outcome. But an outcome definition and measurement schedule are not estimates. Without group results and uncertainty, readers cannot assess the direction, size, or precision of the primary comparison.
The repeated-measure structure is statistically consequential. Between-group differences at particular times and changes within each group answer distinct questions, and multiple time points may require a clear analysis strategy. The registry describes these comparisons but does not report the method or any multiplicity plan. This makes the record useful for identifying the questions while leaving the inferential details unresolved.
The safety entries also show why counts need context. Serious and other adverse events are listed separately, with at-risk counts, but the record does not supply uncertainty estimates, event-attribution details, or an explanation of possible category overlap. These counts should therefore be read as descriptive registry data rather than as a complete comparative safety analysis.
Finally, the combination of randomized allocation and a single-group model designation underscores the importance of internally consistent trial descriptions. The discrepancy is not explained in the registry record. Along with unreported primary results, missing-data methods, and analysis populations, it limits how much can be concluded from the registry entries. The statistical lesson is to separate what the record documents from what would require outcome estimates and fuller methods.
14. 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.
A central limitation is that the numerical primary outcome results are not reported in the registry record. The outcome is defined and its measurement schedule is described, but there are no reported group means, standard deviations, contrasts, confidence intervals, or p-values. Numerical results for the secondary emergence-agitation outcome are also not reported. Effect magnitude and precision therefore cannot be evaluated from the registry record.
The design description contains an unresolved inconsistency: allocation is listed as randomized, while the model is listed as single group. The record does not explain this discrepancy. It also does not describe the randomization method, allocation concealment, or which people were covered by the quadruple-masking designation. These details are not reported in the registry record.
The repeated measurements and multiple comparisons make the missing analysis details particularly relevant. The record does not describe the statistical model, how within-participant dependence was handled, whether baseline adjustment was used, or how multiplicity was considered. Missing-data procedures and analysis populations are also not reported. Enrollment is recorded as 418, but the outcome-specific analysis counts and participant flow are not reported in the registry record.
The serious and other adverse-event entries are limited descriptive data. The record does not report deaths, event attribution, follow-up details, uncertainty estimates, or whether the adverse-event categories can overlap. These omissions constrain comparisons and interpretation of the counts. The study status is completed, but completion does not resolve these reporting gaps.
These limitations concern what is reported in the registry record; they should not be converted into assumptions about what the investigators did or what the trial found. Missing information is not evidence of a null result, a data-quality problem, or an absence of analysis.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Dexmedetomidine as a Rapid Bolus in Children for Emergence Agitation — NCT01528891.
- Registry record last updated 2018-03-08; status last verified 2018-03.
- Results first posted 2015-11-25.
- 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.
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18. Record Summary
The registry identifies NCT01528891 as a completed phase 3 randomized study of dexmedetomidine versus placebo in anesthetized children undergoing tonsillectomy. Quadruple masking is listed, and the placebo is described as normal saline. Enrollment is recorded as 418. The primary outcome is heart rate in beats per minute, measured before injection, repeatedly after injection, and upon arrival in the Post-Anesthesia Care Unit. Emergence agitation is listed as a secondary outcome.
The record also lists serious and other adverse-event counts. However, numerical results for the primary heart-rate outcome and secondary emergence-agitation outcome are not reported in the registry record. The design model is designated single group despite randomized allocation, and the reason for this inconsistency is not reported. Analysis methods, missing-data handling, analysis populations, and multiplicity procedures are not reported in the registry record.