Recovery After Total Intravenous Anesthesia With Ketofol Versus Mixture of Ketofol and Lidocaine for Short Pediatric Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Recovery After Total Intravenous Anesthesia With Ketofol Versus Mixture of Ketofol and Lidocaine for Short Pediatric Surgery (NCT04467424), a randomized phase 2 study. The primary outcome is Effect of TIVA With Ketofol and Ketofol Plus Lidocaine on Extubation Time in Children.

2. Clinical Question

The clinical question concerns a recovery measure following short pediatric surgery, rather than a broad assessment of every aspect of anesthesia or recovery. The posted primary results give the median extubation time as 240.0 seconds with ketofol and 120.0 seconds with ketofol plus lidocaine. The corresponding interquartile ranges are 120.0 to 340.0 seconds and 41.5 to 170.0 seconds. These are descriptive summaries of the observed groups; they do not by themselves establish the size or precision of a treatment effect.

The registry also lists total opioid consumption as a secondary outcome. Numerical results for that outcome are not reported in the registry record. The record names three outcome measures, but the other outcome details and results are not reported in the registry record. The central statistical question that can be addressed from the posted results is therefore limited to the reported extubation-time summaries, without a posted inferential comparison or results for the other listed outcomes.

3. Trial Design

This is a phase 2, randomized, single-masked, parallel-group trial listed as completed. The registry records enrollment of 200 participants. The study dates are 2020-06-20 for start and 2020-11-20 for primary completion. Posted extubation-time results contain 100 participants in each arm.

The two groups received pediatric anesthesia with ketofol or ketofol plus lidocaine. The registry identifies the drugs in the first group as ketamine and propofol, and those in the second group as ketamine, propofol, and lidocaine. Its brief summary describes ketofol for induction and maintenance in one group and a ketofol-with-lidocaine mixture in the other. It also mentions a reduced McFarlan infusion dose. Further details on how that dose was specified or implemented are not reported in the registry record.

Random allocation is the stated design feature for assigning participants to groups. In general, randomization is intended to make treatment groups comparable, on average, with respect to characteristics that could affect an outcome. The registry does not report the sequence-generation method, allocation concealment, or whether assignment was implemented as planned. Masking is listed as single, but which people were masked and how masking was maintained are not reported in the registry record.

The parallel design means the groups are treated as separate arms for the comparison, rather than the same children receiving both approaches in sequence. The listed primary outcome is extubation time, with a timeframe of up to 600 seconds. The record does not report a protocol-level sample-size justification, a detailed statistical analysis plan, or how the listed outcome measures were scheduled and collected beyond the available descriptions.

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

Analysis population for the primary outcome, as defined in the registry: age 1-12, male and female, pediatric short surgery

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.

Population: Age 1-12 years, male and female, for short surgery (max 60 min)

6. Primary Endpoint

The registry lists the primary outcome as Effect of TIVA With Ketofol and Ketofol Plus Lidocaine on Extubation Time in Children, measured over up to 600 seconds.

Extubation time is the time from an unspecified starting point in the procedure to extubation, expressed in seconds. The registry identifies it as the primary outcome for children aged 1–12 years undergoing short pediatric surgery and gives a timeframe of up to 600 seconds. The precise operational definition, including the exact timing origin and criteria for determining the endpoint, is not reported in the registry record.

This measure is used as an indicator of one aspect of emergence and immediate recovery from anesthesia. It focuses on the interval leading to removal of the airway tube, rather than capturing all dimensions of recovery, such as later recovery-room status or patient experience. The brief summary says that extubating time, anesthesia duration, and length of stay in the post-anesthesia care unit would be recorded, but it does not report numerical results for anesthesia duration or post-anesthesia care unit stay.

The primary results are medians with interquartile ranges. A median describes the central position of ordered observations: half the observations are at or below it and half are at or above it, subject to ties. The interquartile range describes the middle half of the observed distribution, from the 25th to the 75th percentile. These summaries are useful when an outcome’s distribution may not be well represented by a mean and standard deviation. They do not show each participant’s experience, the full shape of the distribution, or uncertainty in the estimated group contrast. Confidence intervals for the comparison are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is reported using a median and interquartile range for each arm. Those summaries describe the observed distributions without assuming that extubation times follow a symmetric or normal distribution. The median is the middle value after observations are ordered. The interquartile range runs from the 25th percentile to the 75th percentile and contains the middle half of observations. It describes participant-to-participant variation; it is not a measure of uncertainty in the estimated median or treatment contrast.

What does randomization contribute?

In general, randomization assigns participants to treatment groups by chance. Its statistical purpose is to reduce systematic differences between groups at the point of assignment, including differences in characteristics that may not have been measured. With adequate conduct and follow-up, this supports a fair comparison of outcomes. Randomization does not guarantee that groups will be identical, prevent missing outcomes, or remove biases arising after assignment. The registry labels this study randomized but does not describe sequence generation or allocation concealment, so those implementation details cannot be assessed from the record.

The trial is also described as single-masked. Masking can reduce the influence of expectations on care, measurement, or reporting, depending on who is masked and how the outcome is assessed. The registry does not identify the masked parties or describe the masking procedure. Extubation time is expressed in seconds, but the record does not specify the timing origin, measurement process, or whether outcome assessors were masked. As a result, the potential contribution of masking to outcome measurement cannot be evaluated from the record.

How should the summary statistics be read?

A median is less affected by extreme observations than a mean, which can make it useful for time outcomes when values are not evenly distributed. An interquartile range provides a compact description of the central spread. The values reported for the ketofol arm are a median of 240.0 seconds and an interquartile range from 120.0 to 340.0 seconds. The ketofol-plus-lidocaine arm has a median of 120.0 seconds and an interquartile range from 41.5 to 170.0 seconds. These summaries do not reveal the complete distribution or how individual observations relate to one another.

To assess a treatment contrast statistically, an analysis would need to define the contrast and quantify its uncertainty. A confidence interval is a general way of expressing uncertainty around an estimated effect: it gives a range of values compatible with the data and the chosen method, under that method’s assumptions. A hypothesis test may also summarize compatibility with a null hypothesis using a p-value. Neither a confidence interval nor a p-value for extubation time is reported in the registry record. No statistical test or model is described in the posted results, and the registry lists no analyses.

Why can distributions matter?

General statistical explanation: time outcomes can have asymmetric distributions, particularly when a lower boundary exists or a smaller number of observations have long durations. A mean and standard deviation can be sensitive to such patterns, whereas the median and interquartile range offer robust descriptive summaries. If the aim is to compare groups, the method should match the outcome’s distribution and the study question. The registry does not report distribution plots, an assumed model, or a method for comparing the two groups. It is therefore not possible to judge whether a particular model was used or whether its assumptions were checked.

Over-dispersion is a general concern in some count-data models when observed variability exceeds what a simple model assumes. It matters because an overly restrictive variance assumption can make uncertainty estimates too small. That issue does not directly describe the reported primary outcome, which is a time outcome summarized by medians and interquartile ranges. The registry does list total opioid consumption as a secondary outcome, but its numerical results and statistical method are not reported in the registry record; no claim about the distribution or analysis of that outcome can be made.

What can sample-size planning tell readers?

In general, a sample-size calculation depends on assumptions about the effect to detect, outcome variability, allocation, significance level, and desired power. A planning illustration based on an observed effect is not the trial’s original design justification and is not observed power. The record states that a planning illustration uses a two-sided significance level of 0.05, equal allocation, a normal approximation, and specified fractions of the observed effect. The numerical outputs of those planning illustrations are not reported in the registry record. The trial’s own sample-size justification and its design assumptions are not reported in the registry record, so the adequacy of the enrollment target cannot be assessed from the posted information.

In general, a larger sample can improve precision, but enrollment alone does not show whether the estimate is precise. Precision is assessed using uncertainty measures such as confidence intervals, which are not posted for the primary outcome. The reported arm counts and descriptive summaries therefore provide useful information about the observed groups, while leaving the precision of the treatment contrast unresolved.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists extubation time as the primary outcome and total opioid consumption as a secondary outcome. It also states that three outcome measures are present, but descriptions and results for the additional measure or measures are not reported in the registry record. When several outcomes or comparisons are analyzed, multiplicity can increase the chance of a chance finding if each is tested separately. A statistical plan may address this through a prespecified hierarchy, adjustment, or another strategy. A multiplicity strategy is not reported in the registry record.

The registry does not post a formal analysis of the primary outcome, and it lists no analyses. There is therefore no reported inferential result to interpret for the main comparison, and no information about whether outcome analyses were prespecified, adjusted, or selected after data review. The statistical analysis plan is not reported in the registry record.

Missing-data handling is also not reported in the registry record. The posted primary results contain 100 participants per arm, but the record does not explain whether these are all randomized participants, all participants with an observed outcome, or a different analysis population. It does not report participant flow, exclusions, reasons for missing outcomes, imputation, or sensitivity analyses. These details matter because estimates can be affected if outcome availability is related to treatment assignment or recovery time.

The record does not define an intention-to-treat, per-protocol, or other analysis population. Nor does it report whether outcome data were collected for all enrolled participants through the stated timeframe of up to 600 seconds. Without these details, the extent to which the posted summaries preserve the randomized comparison cannot be determined from the registry record.

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 posted safety figures report zero serious adverse events among 100 participants at risk in the ketofol arm and zero among 100 participants at risk in the ketofol-plus-lidocaine arm. The record also reports zero other adverse events among 100 participants at risk in each arm, and zero deaths in each arm. These are the counts recorded for this trial; they do not establish that the treatments have no risks or that no events occurred outside the recorded categories or observation period.

Adverse-event counts should be read in relation to how events were defined, collected, and followed. The registry does not report the event definitions, monitoring procedures, observation duration, severity criteria, or attribution rules. It also provides no serious adverse-event terms. With no events recorded in these categories, a comparative risk estimate cannot be calculated from the posted counts without adding assumptions, and no such estimate is reported in the registry record.

Zero observed events can occur even when an underlying event risk is not zero, particularly when the observed group is limited in size or the follow-up window is not described. The record’s safety figures are therefore descriptive of the posted participants and reporting period only. They should not be interpreted as proof of absence of harm or as a comprehensive safety assessment.

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

The primary outcome results describe extubation time in the two randomized groups. The ketofol group’s reported median is 240.0 seconds, with an interquartile range of 120.0 to 340.0 seconds. The ketofol-plus-lidocaine group’s reported median is 120.0 seconds, with an interquartile range of 41.5 to 170.0 seconds. These values show the central positions and middle spreads of the observations recorded for each arm.

They do not, on their own, tell readers how certain the comparison is, whether it meets a statistical threshold, or whether the observed pattern would be expected to persist in another group of children. No confidence interval, p-value, or formal comparison is reported in the registry record. Nor is there enough information to assess the extent of missing data, implementation of randomization, outcome assessment, or analysis-population choices. Those uncertainties limit how strongly the descriptive contrast can be interpreted.

The findings concern a particular population and setting: children aged 1–12 years undergoing short surgery and receiving the listed anesthesia approaches. The registry does not provide further detail about surgery types, participant characteristics, or clinical settings. Results should not be assumed to apply to groups or procedures outside the population described in the record.

The primary result also does not answer every question about recovery. The brief summary says anesthesia duration and post-anesthesia care unit stay would be recorded, but their numerical results are not reported in the registry record. Total opioid consumption is listed as a secondary outcome, but its results are likewise not reported in the registry record. The posted extubation-time summaries therefore cannot be treated as a complete evaluation of recovery, resource use, or other outcomes.

In general, a randomized design can strengthen a treatment comparison, but its interpretation depends on sound implementation, complete outcome ascertainment, and appropriate analysis. The record identifies randomization and reports balanced arm counts for the primary results, while leaving many methodological details unspecified. The appropriate conclusion is descriptive: the posted medians and interquartile ranges differ between the two arms, but the registry record does not provide the inferential and follow-up information needed to characterize the precision or robustness of that difference.

13. Why This Trial Matters Statistically

This trial is statistically useful as an example of how a randomized comparison can be reported with descriptive summaries but without a posted analysis of the treatment contrast. The study record identifies a primary outcome, reports arm-specific medians and interquartile ranges, and gives the number of participants represented in each arm. These details allow readers to understand the observed central values and the spread of the middle half of the times.

At the same time, the record illustrates why descriptive summaries and inferential evidence answer different questions. Medians and interquartile ranges characterize observed data. They do not quantify the uncertainty of a between-group estimate. A confidence interval or an appropriate hypothesis test could address uncertainty, but neither is reported in the registry record. The absence of a posted analysis is therefore important: it leaves readers unable to assess precision or statistical compatibility using the trial’s own reported inferential results.

The design labels also matter, but they are not substitutes for methodological detail. Randomization and single masking are recorded, yet the randomization procedures and identities of masked participants are not reported in the registry record. Reporting how outcomes were measured and how missing observations were handled would help readers judge whether the intended protections against bias were achieved.

Finally, the registry names other outcomes and records safety counts, but the available outcome summaries are limited. That distinction helps prevent a narrow primary result from being read as evidence about all aspects of recovery or safety. Statistically, the trial’s record emphasizes the value of transparent outcome definitions, analysis plans, uncertainty estimates, and complete reporting alongside group summaries.

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 primary outcome description identifies extubation time in seconds and a timeframe of up to 600 seconds, but its operational definition is not reported in the registry record. The exact start point for timing, the criteria for extubation, the measurement process, and the handling of observations that may reach the stated timeframe are not described. These omissions make it difficult to assess consistency of measurement and interpret the endpoint’s limits.

The record provides no participant characteristics beyond age range, sex inclusion, and the short-surgery description. Specific surgery types, baseline characteristics, and details of the clinical setting are not reported in the registry record. The methods for sequence generation, allocation concealment, and masking are also not described. Although the study is labeled randomized and single-masked, implementation cannot be evaluated from those labels alone.

Statistical reporting is limited. The primary results are descriptive, with no confidence interval, p-value, or formal between-group analysis. The statistical analysis plan, sample-size justification, missing-data approach, and analysis population are not reported in the registry record. The record does not explain whether all enrolled participants contributed to the posted summaries or how exclusions and incomplete measurements were handled.

Outcome reporting is also incomplete in the available record. Opioid consumption is listed as a secondary outcome, and the brief summary mentions anesthesia duration and post-anesthesia care unit stay; numerical results for these are not reported in the registry record. Three outcome measures are indicated, but full details for all measures are not available. Safety-event definitions and monitoring duration are not described. Together, these limitations restrict interpretation to the posted extubation-time summaries and recorded event counts, without establishing the precision, completeness, or broader relevance of the results.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Recovery After Total Intravenous Anesthesia With Ketofol Versus Mixture of Ketofol and Lidocaine for Short Pediatric Surgery — NCT04467424.
• Registry record last updated 2021-02-04; status last verified 2021-01.
• Results first posted 2021-02-04.
• 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

The registry record describes a completed phase 2, randomized, single-masked, parallel-group trial with enrollment of 200. It compares ketofol with ketofol plus lidocaine for pediatric anesthesia in children aged 1–12 years undergoing short surgery. The recorded study start is 2020-06-20, and primary completion is 2020-11-20.

Extubation time is the primary outcome, reported in seconds as a median and interquartile range, with a stated timeframe of up to 600 seconds. The arm results include 100 participants each. The ketofol arm has a median of 240.0 seconds and an interquartile range of 120.0 to 340.0 seconds; the ketofol-plus-lidocaine arm has a median of 120.0 seconds and an interquartile range of 41.5 to 170.0 seconds.

No inferential analysis of the primary comparison is reported in the registry record. The record lists total opioid consumption as a secondary outcome, but numerical results for it are not reported in the registry record. Safety figures record zero serious adverse events, zero other adverse events, and zero deaths in each arm.