Anesthesia With Endotracheal Laser Tube: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Anesthesia With Endotracheal Laser Tube (NCT03044418), a registered phase not stated study. The primary outcome is Number of Participants With Side Effects.

2. Clinical Question

3. Trial Design

The registry identifies this study as “Anesthesia With Endotracheal Laser Tube,” with the official title “Anesthesia of Endolaryngeal Surgery With a Special Endotracheal Laser Tube.” It lists University of Pecs as sponsor, an enrollment of 30, a start date of 2017-01-01, primary completion on 2017-06-05, and a status of COMPLETED. The study description concerns use of a special ET laser tube during anesthesia for endolaryngeal laser surgery.

The described intervention is application of the ET laser tube during total intravenous anesthesia with propofol. The registry result material identifies one group titled “The Frequency of Side Effects of Special ET Laser Tube Using.” A randomized allocation is not stated, and the registry explicitly flags that this is not a randomized comparison and that the arms are not a like-for-like control comparison. A protocol-defined control group, allocation method, masking approach, or sequence-generation procedure is not reported in the registry record.

The registry lists one outcome measure. Its primary outcome is the number of participants with side effects, with the description referring to an airway or special laser-tube problem and a timeframe of 5 months. The posted adverse-event figures list participants at risk and affected participants for serious and other adverse-event categories, as well as deaths. Those safety summaries do not establish that they are identical in definition or ascertainment to the primary outcome.

The record does not report a detailed analysis plan, an enrollment rationale, or how the outcome was assessed. It also does not describe participant flow, exclusions after enrollment, or whether all enrolled participants contributed to every reported safety category. These omissions limit what can be inferred about the design and completeness of the analysis.

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 Number of Participants With Side Effects, measured over 5 months.

The primary endpoint is titled “Number of Participants With Side Effects.” It is a count of participants, and its description identifies the events of interest as a problem with the airway or special laser tube. The registry gives a timeframe of 5 months. The posted outcome is therefore intended to describe how many participants met this event definition during that timeframe, rather than how often an event occurred per procedure or how severe each event was.

In general, a participant-level binary endpoint classifies each participant according to whether the defined event occurred. Counting participants can provide a direct summary of how frequently an outcome was observed in the study group. The usefulness of that summary depends on a clear event definition, consistent assessment, and knowledge of which participants were observed for the relevant period.

The registry does not report further operational criteria for what qualified as an airway or tube problem, how events were sought, or whether independent adjudication was used. It also does not provide a separate time-to-event measure or an event count that distinguishes multiple episodes in one participant. The result should be read as a participant count under the registry’s stated endpoint, not as a complete description of event timing, severity, or recurrence.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count represent?

The primary outcome is a participant count: the number recorded with a side effect described as a problem with the airway or special laser tube. In general, this kind of endpoint starts with a definition that assigns each participant to an event or no-event category. The reported count then describes the participants classified as having the event during the stated observation period. It does not by itself describe the number of separate episodes, the duration of a problem, or its severity.

The registry gives a timeframe of 5 months. For an event count to be interpreted fully, readers also need to know how that period is applied to each participant, when follow-up begins and ends, and how participants with incomplete observation are handled. Those details are not reported in the registry record. Consequently, the count can be read as the posted result, but it cannot be expanded into a detailed account of individual follow-up.

How should a zero count be understood?

In general, an observed count of zero means no event was recorded in the stated group under the study’s event definition and ascertainment. It is not proof that the event cannot occur. A confidence interval is a statistical range that expresses uncertainty around an estimate; it can help readers distinguish a point estimate from the range of values still compatible with the data under the chosen method. No confidence interval is reported in the registry record for the primary endpoint or the listed adverse-event counts.

A proportion or rate could be useful in other settings, but this explanation does not calculate one. The posted record gives affected and at-risk counts. It does not report a separate rate per procedure, unit of time, or exposure. Those measures would require appropriate denominators and definitions, and they should not be inferred from the participant count alone.

What can a comparison establish?

In general, a comparative study estimates how outcomes differ between groups, while a single group’s event count describes only what was observed in that group. A causal interpretation depends on a credible comparison and a design that supports it. Here, the registry notes that allocation is not stated and that the arms are not a like-for-like control comparison. The posted result therefore does not establish a contrast between the ET laser tube approach and another approach.

Even when two groups are listed, their counts are not automatically comparable. Differences in participant selection, procedure, event assessment, follow-up, or other care can affect observed outcomes. A statistical adjustment can address some measured differences when an appropriate analysis is planned and reported, but no adjusted analysis is listed. The registry records zero analyses.

What do statistical significance and precision mean?

In general, a significance test evaluates how compatible data are with a specified statistical hypothesis under an assumed model. A p-value is one output of such a test; it is not the probability that a treatment works, nor a measure of clinical importance. The registry record does not report a p-value or a comparative hypothesis test for this outcome. With no like-for-like comparator described, a comparative significance test would not be supported by the posted information.

Precision concerns the uncertainty around an estimate. A small or sparse set of events can leave substantial uncertainty even when the observed count is zero. This is why an event count should not be read as an exact estimate of risk for other participants or settings. The registry record does not report an uncertainty interval, a model, or a plan for estimating precision.

What are the planning illustrations?

In general, a sample-size calculation describes how many participants a future study might plan to enroll under stated assumptions. It is not an observed result and does not show that a completed study had a particular level of power. The registry record characterizes the planning illustrations as based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a stated fraction of the observed effect. It also distinguishes total events for time-to-event calculations from participants per arm for other calculations.

Those planning assumptions do not establish that the trial itself used that design. The record does not report a sample-size justification or say that the study was planned with those assumptions. Planning values cannot remedy the absence of a reported randomized comparison or turn the observed counts into comparative evidence. They should be interpreted as illustrations under assumptions, not as a measure of observed power or as proof that the study could detect a particular effect.

Finally, the registry does not report methods for missing data, analysis populations, multiplicity control, or interim analyses. These are relevant statistical design choices because they affect how outcomes are defined, which observations contribute, and how uncertainty is interpreted. Without those details, the posted count remains a descriptive finding with limits that cannot be resolved from the registry record.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Anesthesia With Laser Tube")
n      <- c(30)
events <- c(0)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Anesthesia With Laser Tube  30  0  0.0  0.0  11.6  0.0  11.4  0.1  11.2

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and zero analyses. It does not report whether the primary endpoint was selected from a larger set of planned outcomes, whether secondary outcomes were assessed, or whether any multiplicity strategy was used. In general, multiplicity arises when several hypotheses or outcomes are tested; without a plan, repeated testing can increase the chance of a nominally notable result occurring by chance. No multiplicity adjustment or testing framework is reported, and no inferential result is posted for the listed endpoint.

Missing-data procedures are not reported in the registry record. The available information does not state whether any participants had incomplete follow-up, how an unobserved endpoint would be classified, or whether any imputation or sensitivity analysis was performed. The recorded enrollment is 30, but that number alone does not establish that all enrolled participants had complete outcome information or contributed to every safety category.

The analysis populations are also not described. The record does not say whether results were based on all enrolled participants, participants who received the intervention, or another defined group. It does not describe exclusions, protocol deviations, or how any such cases were handled. These details matter because the group contributing to an analysis can differ from the group initially enrolled.

In general, a prespecified analysis population and transparent accounting of missing outcomes help readers judge whether a reported count reflects the intended study population. Here, the registry provides counts at risk and affected for the adverse-event categories but does not explain the relationship of those counts to the primary endpoint population. The result should therefore be read as the posted summary, with completeness and analysis-population details not reported in the registry record.

12. 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 serious adverse-event listing records 30 participants at risk and 0 affected. The other adverse-event listing also records 30 participants at risk and 0 affected. The death count is 0. These figures describe the entries in the registry’s safety summary; they do not mean that every possible safety outcome was assessed or that no event could occur outside the recorded categories.

In general, an adverse-event summary depends on how events are defined, collected, classified, and followed. “Serious” and “other” are categories in the posted record, but further definitions and assessment procedures are not reported in the registry record. The record also does not explain whether these categories overlap with the primary outcome’s airway or special laser-tube problem definition.

Zero recorded events should not be interpreted as proof of zero underlying risk. The safety counts are descriptive and do not include an uncertainty interval or a comparison group suitable for estimating relative safety. The record does not report information about event severity beyond the listed categories, timing, recurrence, or individual participant circumstances.

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

The result documents a specific observation: the registry posts no participants affected in its serious or other adverse-event categories, and no deaths. The primary outcome is a count of participants with side effects described as airway or special laser-tube problems, over a timeframe of 5 months. These statements describe the posted record; they are not a declaration that the intervention is risk-free.

The study concerns a special ET laser tube used during endolaryngeal laser surgery with propofol anesthesia. Its result cannot be generalized automatically to other tube designs, anesthesia approaches, procedures, participant groups, or care settings. The registry record does not give enough detail about eligibility or participant characteristics to define precisely who the observed experience represents.

The result also does not establish that use of the tube changes event frequency. A treatment effect is a contrast between outcomes under an intervention and an appropriate alternative. The record does not provide a randomized, like-for-like control comparison, and allocation is not stated. A count from the described group cannot answer what would have happened to comparable participants under another approach.

Nor does the count provide a precise estimate of the event probability. No confidence interval, model-based estimate, or inferential analysis is reported. In general, zero observed events can coexist with uncertainty about the frequency that might be seen in a broader population. The available figures also do not describe event timing, repeated episodes, severity beyond the listed safety categories, or completeness of follow-up.

The defensible interpretation is limited but useful: the registry records the observed safety counts for the listed categories and describes the endpoint used to assess airway or tube problems. The figures can inform understanding of what was documented in this study, while questions about comparative effects, broader safety, and precision remain unanswered by the registry record.

14. Why This Trial Matters Statistically

This trial is statistically notable as an example of the difference between describing events and estimating a comparative effect. A participant count can summarize observed experience, but a treatment comparison requires a suitable reference group and a design that supports interpreting differences. The registry record describes an ET laser tube approach and flags that the arms are not a like-for-like control comparison; it does not report allocation.

The endpoint is clinically specific in its wording: a participant is counted for a side effect described as a problem with the airway or special laser tube. This focus makes clear what the posted outcome is intended to capture, while also highlighting the importance of operational definitions. The registry does not report detailed criteria or assessment procedures. Statistical interpretation is consequently shaped not only by the count, but by the limits of knowing exactly how events were identified.

The zero event counts also illustrate why descriptive results and uncertainty should be kept distinct. In general, a study can observe no events and still leave uncertainty about how often an event might occur in a broader population. Without an uncertainty interval or an appropriate comparative analysis, the record supports a description of recorded events rather than a precise population estimate.

Finally, the record lists one outcome measure and zero analyses, while key details about missing data, analysis populations, and multiplicity are not reported. Recognizing these absences helps readers avoid treating a brief registry summary as a complete statistical analysis. The result is informative as a record of observed counts, but its scope is narrower than a controlled estimate of comparative safety or effectiveness.

15. 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 trial-specific limitation is the lack of a reported like-for-like control comparison. The registry explicitly flags that this is not a randomized comparison and states that allocation is not reported. Consequently, the posted counts cannot estimate how outcomes differ from another anesthesia or tube approach.

The event definition is brief. The primary outcome refers to an airway or special laser-tube problem, but detailed criteria for determining whether a participant had such a problem are not reported in the registry record. Event ascertainment methods, assessor roles, and any adjudication process are also not described. This limits reproducibility and makes it difficult to compare the endpoint with differently defined outcomes.

The record gives an enrollment of 30 and lists safety counts, but does not describe participant characteristics, eligibility criteria, individual follow-up, exclusions, or missing outcomes. It is therefore unclear from the registry record how representative the observed group was or whether every enrolled participant contributed information for the full timeframe.

The registry lists one outcome measure and zero analyses. It does not report a sample-size justification, statistical analysis plan, confidence intervals, or model-based estimates. The planning illustrations are not evidence of the trial’s own design or observed power. Further, the relation between the primary endpoint and the serious and other adverse-event categories is not specified, so the categories should not be assumed to measure exactly the same events.

These limitations constrain interpretation to the descriptive registry findings. They do not negate the reported counts, but they prevent stronger conclusions about comparative effects, the frequency of events in other populations, and the precision or completeness of the safety assessment.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Anesthesia With Endotracheal Laser Tube — NCT03044418.
• Registry record last updated 2021-09-20; status last verified 2021-08.
• Results first posted 2021-09-20.
• 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.

19. Record Summary

NCT03044418 is a completed study sponsored by University of Pecs, with a recorded enrollment of 30. The registry lists a start date of 2017-01-01 and primary completion on 2017-06-05. The study examines use of a special ET laser tube during endolaryngeal laser surgery with propofol anesthesia.

The primary outcome is the number of participants with side effects described as an airway or special laser-tube problem, with a timeframe of 5 months. The safety record lists 0 affected participants among 30 at risk for serious adverse events and 0 among 30 at risk for other adverse events; deaths are recorded as 0. The registry lists one outcome measure and zero analyses. Allocation, a like-for-like control comparison, analysis methods, missing-data procedures, and analysis populations are not reported in the registry record. The posted findings are descriptive counts, not a comparative estimate.