Ondansetron as a Strategy for Reducing Propofol Injection Pain in Pediatrics: a Randomized Controlled Trial: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Ondansetron as a Strategy for Reducing Propofol Injection Pain in Pediatrics: a Randomized Controlled Trial (NCT05378113), a randomized phase 2 study. The primary outcome is Verbal Rating Scale (VRS).

2. Clinical Question

The trial was designed to investigate whether giving ondansetron before propofol could reduce the pain or distress associated with propofol injection in pediatric patients. It used random allocation to compare two premedication strategies, rather than comparing either strategy with no premedication. The registry describes the study as single-masked, but does not report who was masked or how masking was maintained.

The record lists the study as terminated and gives a primary completion date of 2023-08-03. It does not report why the trial was terminated. Although the primary question is clinically focused, the registry record does not provide the observed verbal rating scores, their variability, or a statistical comparison between groups. The design and intended measure therefore describe the question the study set out to address, not an answer to that question.

3. Trial Design

This was a randomized, single-site, parallel-group phase 2 trial sponsored by Emory University. The registry lists enrollment of 6 and identifies pediatric injection-site irritation as the condition. The study start date is 2023-05-18, the primary completion date is 2023-08-03, and the status is terminated. The record does not state the reason for termination.

Participants were assigned to ondansetron premedication or lidocaine premedication. In the ondansetron group, the planned regimen was ondansetron 0.15mg/kg by intravenous push, followed immediately by propofol 2mg/kg for induction, then a 10cc normal saline flush. In the lidocaine group, the regimen was lidocaine 2% at 1mg/kg by intravenous push, followed immediately by the same propofol dose and flush. These descriptions define the intended treatment contrast; they do not establish how many participants received each regimen or whether every planned dose was delivered.

Randomization is intended to make assigned groups comparable, on average, with respect to factors that could affect the outcome. In a small trial, however, random allocation does not ensure that the groups are closely balanced on every patient characteristic. The record does not report the randomization sequence, allocation concealment procedures, masking details beyond single masking, or baseline characteristics.

The primary outcome is a verbal rating scale (VRS) score measured at baseline and during propofol injection, specified as 30 seconds. The scale has scores from 0 to 3, with higher scores indicating more perceived pain or distress. Because the outcome is described at multiple time points, the posted record does not reduce it to one comparison. It reports no analyses. The registry does not report a sample-size justification, a detailed statistical analysis plan, or whether the study was intended to support a confirmatory conclusion.

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 Verbal Rating Scale (VRS), measured over Baseline, during propofol injection (30 seconds).

The primary endpoint is the Verbal Rating Scale (VRS), a score intended to capture observable verbal indications of pain or distress during propofol injection. The record describes scores from 0 to 3: 0 means no verbal indication of pain, 1 means purposeless moaning, 2 means explicit protest, and 3 means screaming or crying of pain. Higher scores indicate a higher level of perceived pain or distress.

The VRS is used because verbal behavior during an injection can provide an observable, graded measure of the response to the procedure. A scale preserves distinctions between different levels of verbal reaction rather than reducing the observation to a simple yes-or-no indicator. This is a general explanation of why graded measures can be useful; it does not establish how well the scale performed in this trial.

The registry specifies measurement at baseline and during propofol injection, with the injection-period assessment identified as 30 seconds. It does not report the scores, group summaries, or a method for combining or comparing measurements across time points. The registry record therefore identifies what the endpoint was intended to measure, but does not provide the results needed to assess the observed pain or distress ratings or their precision.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does randomization contribute?

Randomization assigns participants to intervention groups using a chance-based process. In general, this helps prevent clinicians or participants from choosing a group based on characteristics that might also relate to an outcome. It supports a fair comparison of assigned strategies, especially when outcomes are analyzed according to the planned assignment. Randomization does not guarantee that groups will be identical in a particular trial, and chance imbalances can be important when enrollment is small.

The registry describes this study as randomized, single-masked, and parallel. Parallel means that participants are assigned to one group rather than receiving both premedications in sequence. Single-masked indicates that one party was intended to be unaware of assignment, but the record does not identify that party or describe the masking procedure. Allocation concealment, sequence generation, and the analysis population are not reported in the registry record. These details matter because they help readers assess how assignment was implemented and how participants were included in analyses.

How should a continuous score be analyzed?

The primary outcome is described as a mean score with standard deviation, so it is treated as a continuous measure in the registry. A common general approach to comparing two groups on a continuous outcome is to estimate each group’s mean and then estimate the difference between those means. The estimate is most useful when accompanied by a confidence interval, which expresses uncertainty about the size and direction of the difference under the model assumptions. A p-value, when reported, addresses compatibility with a specified null hypothesis; by itself, it does not show the size or clinical importance of an effect.

The VRS is bounded from 0 to 3 and uses ordered verbal categories. Treating such scores as continuous can be a practical summary, but it makes assumptions about how the steps between scores should be interpreted. A mean can summarize a group’s score distribution, but it may conceal whether observations cluster at particular categories. Other approaches may instead use the ordered categories directly. The registry record does not report which model or test was used, nor does it provide results that would allow the distribution to be examined.

Standard deviation describes the spread of individual scores around a group mean. It is not the same as the uncertainty of the mean or the uncertainty of the difference between group means. A confidence interval for a group contrast depends on the observed variability and the amount of information in the groups, as well as the analysis assumptions. No standard deviations or intervals for the primary endpoint are reported in the registry record.

Why do time points and outcome categories matter?

The endpoint description identifies baseline and an assessment during propofol injection, with the injection assessment specified as 30 seconds. Repeated measurements on the same participant are related rather than independent. In general, an analysis of repeated measurements should account for that relationship or define in advance which time point or change is the primary contrast. If several time points or outcome categories are examined, the analysis also needs to clarify which comparisons are central and how additional comparisons will be interpreted.

The registry record explicitly does not reduce the primary outcome, which has several categories or time points, to one comparison. It lists no analyses. As a result, there is no reported model, test, contrast, or time-point summary to explain as the trial’s actual inferential method. A reader should not substitute an assumed analysis for an unreported one.

What do the planning assumptions mean?

The record describes planning illustrations based on an observed effect, using a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It states that the effect to detect is a stated fraction of the observed effect. Such illustrations are conditional calculations: they show what participant requirements would follow under specified assumptions, rather than documenting the trial’s original design or its realized statistical power.

The record does not report the numerical planning illustrations or identify a sample-size justification from the trial’s own design. The planning assumptions should therefore not be read as proof that the trial was designed around a particular target, or that a particular power was achieved. A planning sample size is not observed power. Observed power is not a substitute for reporting an effect estimate and its uncertainty.

When over-dispersion is present in a statistical model for counts, the variability exceeds what a simpler model assumes. In general, failing to account for over-dispersion can make uncertainty estimates too small and tests too optimistic. This is a general statistical point, not a description of an analysis in this trial: the endpoint is a VRS score, and the registry does not report a model that would permit an assessment of over-dispersion.

What can be concluded from the posted analysis record?

No analyses are listed, and no primary outcome summary or inferential result is reported. Accordingly, there is no trial-specific estimate, confidence interval, or p-value to interpret. The registry does not report whether any analysis was conducted outside the posted record. A transparent statistical interpretation must distinguish the intended design and endpoint from observed results: the former are described, while the latter are not available in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome is described across baseline and the period during propofol injection, and the registry notes several categories or time points without reducing them to one comparison. When multiple measurements or comparisons are considered, multiplicity becomes relevant: repeated opportunities to identify a difference can make a result appear more compelling by chance if the analysis does not account for the number and structure of comparisons. This is a general concern, not evidence that a particular adjustment was or was not used in this trial.

The registry record lists no analyses and does not report a primary time-point contrast, a hierarchy of outcomes, or a method for addressing multiplicity. It is therefore not possible to determine what comparison would have been treated as primary in an analysis or how additional comparisons would have been handled.

Missing-data information is also not reported. The registry does not give the number of participants with VRS observations at each assessment, reasons for missing measurements, or methods for handling incomplete observations. The enrollment entry alone does not establish completion of the endpoint assessments or inclusion in an analysis.

The analysis population is not reported in the registry record. In general, an analysis of participants according to randomized assignment estimates the effect of assignment, while analyses restricted by treatment received or data availability can address different questions and may introduce bias. No such approach should be attributed to this trial without a reported analysis plan or results. The record does not state whether the analysis was intention-to-treat, per-protocol, or based on another population.

11. 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 safety record lists zero serious adverse events and zero other adverse events in both the ondansetron premedication group and the lidocaine premedication group. It lists 3 at risk in each group for serious adverse events and 3 at risk in each group for other adverse events. Deaths are listed as zero in both groups. No serious adverse event terms are listed.

These entries describe the safety information posted in the registry; they do not establish that no symptoms or events occurred outside the categories or reporting period represented by these entries. The registry record does not provide event definitions, collection procedures, follow-up duration, or additional narrative about safety monitoring. It also does not report how the at-risk counts relate to completion of the primary endpoint assessments.

Zero reported events should not be interpreted as evidence that the two premedication strategies have identical safety profiles. With limited information, absence of a listed event is not a precise estimate of how often an event might occur in a broader population. The entries are descriptive safety counts, not a statistical comparison, and they do not answer the primary question about VRS scores during propofol injection.

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

The registry record establishes the question the trial was intended to study: whether VRS ratings during propofol injection differed between pediatric patients assigned to ondansetron premedication and those assigned to lidocaine premedication. It describes the regimens and the scale, and lists enrollment of 6. It also reports the study status as terminated and includes safety entries for both groups.

It does not report the primary outcome scores, group means, standard deviations, an estimated contrast, confidence intervals, or p-values. Thus, the record cannot show the observed direction or size of any difference, nor how precisely that difference was estimated. The lack of a posted result is not evidence that the groups had equal outcomes, and it is not evidence that one premedication strategy performed better. No conclusion about the primary endpoint can be supported from the information recorded.

The safety entries list zero serious adverse events, zero other adverse events, and zero deaths in each group, with 3 at risk in each group for the serious and other event summaries. These counts are limited descriptive information. They do not establish equivalence in safety, and the record does not supply the detail needed to assess the scope of event surveillance.

In general, a small study can be useful for feasibility or early investigation, but estimates from limited information are often imprecise. That general point does not establish the purpose or intended precision of this particular study; its sample-size justification is not reported in the registry record. The record also does not state why the trial was terminated or whether the planned assessments were completed.

The appropriate interpretation is therefore narrow: the registry documents a randomized comparison and its planned endpoint, but does not contain the primary outcome analysis needed to evaluate that comparison. The posted record should not be treated as evidence for a treatment effect, no treatment effect, or a definitive safety difference.

13. Why This Trial Matters Statistically

This trial raises a useful statistical question about how to evaluate a patient response that is recorded on a short ordered scale. A mean and standard deviation can summarize such scores, but readers also need to understand the scale’s categories and whether the analysis treats its steps as comparable. The record describes the VRS categories and the direction of the score, allowing the intended measurement to be understood even though the results are absent.

The study also illustrates why a clearly defined primary comparison matters when an outcome is collected at multiple times. Baseline and the injection-period assessment are both identified, but the registry does not reduce the outcome to one contrast or report an analysis. In general, specifying the time point or change of primary interest helps limit ambiguity and makes it easier to interpret uncertainty and multiplicity. The record does not report whether such a specification existed elsewhere.

Randomized allocation is an important design feature, but it cannot replace transparent reporting of participant flow, analysis populations, outcome summaries, and uncertainty. These details help distinguish a design’s intended comparison from evidence about what was observed. Here, the registry record provides the intervention descriptions and the endpoint definition but no primary results, so the key statistical comparison remains unresolved.

The safety entries also show why event counts need context. Counts without detailed ascertainment information or precision estimates are descriptive, and zero reported events do not establish that the underlying risks are identical. The main statistical contribution of the record is consequently its description of a planned pediatric comparison, not an estimate of the relative outcome or safety profiles.

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.

The main limitation for interpretation is the absence of posted primary outcome results. The registry identifies the VRS and its assessment periods but does not report group scores, variability, an effect estimate, a confidence interval, or a p-value. Without these results, neither the direction nor precision of the primary comparison can be assessed.

Enrollment is listed as 6, and the study status is terminated. The record does not explain the termination, report participant flow, or state how many participants contributed endpoint measurements. It is not possible to determine whether all enrolled participants received their assigned regimen or completed assessments. The safety entries list 3 at risk in each group, but those counts do not supply the missing endpoint information.

The record calls the study single-masked but does not identify who was masked or describe how masking was achieved. It also does not report randomization procedures, allocation concealment, baseline characteristics, eligibility details, or adherence. Each of these details can help readers judge how the comparison was conducted and whether the groups and measurements were handled consistently.

The primary outcome involves multiple categories or time points, and the record does not reduce it to one comparison. No analyses are listed, and the statistical analysis plan, missing-data approach, and analysis population are not reported. The registry does not provide a sample-size justification from the trial’s own design or the reason the study stopped. These omissions limit assessment of the intended inferential approach as well as the observed evidence.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Ondansetron as a Strategy for Reducing Propofol Injection Pain in Pediatrics: a Randomized Controlled Trial — NCT05378113.
• Registry record last updated 2026-04-24; status last verified 2026-04.
• Results first posted 2026-04-24.
• 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.

18. Record Summary

NCT05378113 is a randomized, single-masked, parallel-group phase 2 trial sponsored by Emory University. It compared ondansetron premedication with lidocaine premedication before propofol induction in pediatric patients at Children's Healthcare of Atlanta at Egleston. The registry lists enrollment of 6, a start date of 2023-05-18, a primary completion date of 2023-08-03, and terminated status.

The primary endpoint was the VRS, scored from 0 to 3, at baseline and during propofol injection, specified as 30 seconds. The registry record lists no analyses and does not report primary outcome results or the reason for termination. Safety entries list zero serious adverse events, zero other adverse events, and zero deaths in both groups.