AuraOnce Performance Observation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for AuraOnce Performance Observation (NCT04128527), a registered phase not stated study. The primary outcome is Number of Participants With Leakage Observed During Procedure.

2. Clinical Question

The study focused on device performance during a diagnostic flexible bronchoscopy in general anaesthesia. Its primary outcome was a count of participants with leakage observed during the procedure. This is a descriptive question about whether leakage was noted during use, not a comparison of the device with another mask or with an alternative airway approach.

Other listed outcomes address investigator assessments of ease of insertion, ease of obtaining a seal, and overall performance, each on a 5-point scale. The record also lists correct mask placement and a folded mask tip. These measures describe procedural performance from several perspectives: investigator ratings, placement status, and an observed device position feature. Their results are not reported in the registry record.

The design is suited to recording experience in the specified clinical setting, but it cannot by itself establish how performance compares with another device or what would happen in a different setting. The registry record does not report an analysis population definition, outcome counts, or statistical estimates for the primary question.

3. Trial Design

This was a prospective, single-center, observational, non-controlled, non-interventional evaluation. It took place in Denmark and was intended to assess insertion and sealing performance of the AuraOnce disposable laryngeal mask in adults having diagnostic flexible bronchoscopy under general anaesthesia. The registry record describes the mask as being used within its intended use and according to normal clinical procedure.

The planned investigation period for an individual procedure was one day, during one bronchoscopy procedure, with the primary outcome timeframe described as during the procedure, under 1 hour. The record describes recruitment during a one month period in October 2019. The recorded study start is 2019-10-09, primary completion is 2019-11-05, and status is COMPLETED. Enrollment is recorded as 16; the brief description gives a planned minimum of 15 and maximum of 20 adults.

The intervention is placement of a laryngeal mask. No comparator group is listed, and allocation is not stated. As a result, the design offers no concurrent control for interpreting ratings or observed events. The study does not assign participants to competing approaches, and its non-interventional character means the observations concern use during routine clinical procedure rather than a randomized test of efficacy.

The stated secondary outcomes include investigator ratings of insertion, seal, and overall performance on 5-point scales, along with counts for correct placement and a folded mask tip. The registry record lists 6 outcome measures and 0 analyses. It does not report a protocol-level statistical plan, a sample-size justification, or details of analysis populations. The study’s completed status and enrollment do not establish that every planned measure has a posted result.

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.

Population: No baseline data was collected on participants

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Leakage Observed During Procedure, measured over During procedure, less than 1 hour.

The primary endpoint is the number of participants with leakage observed during the procedure. The registry defines the observation as yes or no and asks that signs of leakage be entered when leakage is present. The timeframe is during the procedure, under 1 hour. This endpoint therefore captures whether leakage was noted in the course of the laryngeal-mask use being evaluated.

A binary endpoint can be useful for a procedural quality assessment because it records the occurrence of a specified event in a simple, clinically recognizable form. It can be summarized as a count of participants with the event, alongside the number assessed, if both are reported. The count alone does not describe the duration, severity, or consequences of leakage; the record’s instruction to enter signs of leakage could add descriptive detail, but those details are not reported in the registry record.

The endpoint is not a comparative effect measure. With no control group, a leakage count cannot estimate a difference between AuraOnce and another device or procedure. Interpretation also depends on how leakage was recognized and recorded. The registry provides the yes/no description but does not report further operational criteria, assessor training, or an adjudication process. Most importantly, the observed primary endpoint count and any associated signs are not reported in the registry record, so the endpoint’s result cannot be assessed from the posted information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary measure is binary: leakage is recorded as yes or no during the procedure. In general, a binary endpoint describes whether a defined event occurred for each assessed participant. A count of participants with an event is easiest to interpret when the corresponding number assessed is also available and the event definition is applied consistently. The registry identifies the outcome and its timeframe, but the observed leakage count and further event details are not reported in the registry record.

For a binary outcome, an analysis may report the event count and the proportion of assessed participants with the event. A confidence interval can express the uncertainty around an estimated proportion: it gives a range of values compatible with the data under the method’s assumptions. With a small study, such an interval can be wide, so a point estimate alone may give a misleading impression of precision. No proportion or confidence interval for leakage is reported in the registry record, and none can be derived from the information posted about that endpoint.

The distinction between an endpoint and a safety outcome matters. Leakage is the stated primary performance measure. The safety entries separately summarize participants at risk, those affected, and deaths. Those safety counts do not stand in for the primary endpoint, even if both could in principle involve events during the same procedure. The registry does not report a cross-classification or explanation linking leakage observations to adverse-event categories.

The secondary measures use different forms of data. The insertion, sealing, and overall-performance outcomes are investigator evaluations on 5-point scales with labeled endpoints. Such scales are ordered: a higher category represents a more favorable rating according to the labels. The spacing between neighboring categories is not necessarily equal, so treating scores as if each step represented the same change requires an analytic justification. The registry record does not report a scoring analysis or how the ordinal ratings were summarized. Correct placement and a folded mask tip are count-based outcomes, but their observed counts are not reported.

Study design determines which statistical conclusions are supportable. In general, a randomized comparison can help separate treatment differences from other systematic differences between groups. This evaluation is described as non-controlled and non-interventional, with no comparator. It can therefore describe observed performance in its setting if results are available, but it cannot estimate a comparative treatment effect or establish that an outcome was caused by the device. There is no basis in the registry record for an adjusted or unadjusted between-group analysis.

The record lists 0 analyses. It does not report an inferential statistical plan, a prespecified hypothesis test, confidence-interval method, or adjustment strategy. This does not establish that no analysis occurred outside the posted record; it means those methods and results are not reported in the registry record. A p-value, were one reported, would address compatibility of data with a specified statistical model and null hypothesis; it would not by itself describe the size, importance, or precision of a performance result. No p-value is reported.

The sample-size material is a planning illustration, not evidence of observed power. Its stated assumptions include a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and planning to detect a stated fraction of an observed effect. Those are comparative planning assumptions and should not be mistaken for the design of this non-controlled study. The record does not report a trial-specific sample-size justification, and the posted outcome results do not give an observed effect on which to base an independent assessment of those illustrations. A planning calculation describes what a hypothetical design might require under stated assumptions; it does not show that the completed study had a particular probability of detecting an effect.

Over-dispersion is a general issue when count data vary more than a chosen statistical model expects. If a model assumes a particular amount of variability but the data are more variable, standard errors can be too small and confidence intervals can be too narrow. This concept is not directly an analysis result for the stated binary endpoint, and the registry record does not report a model-based count analysis. The endpoint data required to evaluate any such concern are not reported.

Interpretation also depends on the denominator and observation completeness. An event count without the number assessed cannot show the event frequency among observed participants. If some assessments are missing, a complete-case result may differ from a result using a defined missing-data method. The registry does not report endpoint-specific denominators, missingness, or missing-data handling. It also does not report whether all enrolled participants were included in every outcome analysis. These omissions limit assessment of both the precision and representativeness of any unreported results.

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("Adults, Laryngeal Mask")
n      <- c(16)
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  Adults, Laryngeal Mask  16  0  0.0  0.0  20.6  0.0  19.4  0.1  19.5

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 6 outcome measures, including the primary leakage measure and secondary ratings and placement observations. When a study assesses multiple outcomes, there are generally more opportunities for chance findings if many significance tests are conducted. Statistical methods can address this issue through prespecified outcome hierarchies or multiplicity adjustments, but such choices depend on the study’s plan and question. The registry record does not report a multiplicity strategy, a hypothesis-testing plan, or analysis results. With 0 analyses listed, no test-level conclusions can be reviewed.

Missing data are also not described. The record does not report whether every participant had an evaluable leakage assessment, whether every investigator rating was completed, or how incomplete observations were handled. Enrollment alone does not establish endpoint completeness. Without endpoint-specific denominators and missingness information, a reader cannot tell whether an unreported outcome reflects no events, an incomplete assessment, or the absence of posted results.

The registry record does not define an analysis population, such as a set of participants included for a particular outcome, and does not state whether any exclusions occurred. It also does not report participant flow or a reconciliation between enrollment and endpoint assessments. These details are important because counts and ratings are interpretable only in relation to who was assessed and how the assessment set was defined. In their absence, the outcome results cannot be reconstructed or checked for completeness.

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 safety record lists the group as Adults, Laryngeal Mask. For serious adverse events, it reports 16 at risk, 0 affected, and 0 deaths. For other adverse events, it reports 16 at risk and 0 affected. The record lists no serious adverse-event terms. These are the figures recorded for the safety categories; they are not the primary leakage outcome.

An at-risk count identifies the group included in the safety summary, while an affected count records participants with the listed type of event. Zero affected in these entries means that no affected participants are recorded in those categories in the posted safety data. It does not establish that every possible event was actively sought, that reporting was complete, or that an event could not occur in another setting. The registry record does not provide further monitoring or ascertainment details.

These safety counts should be read alongside the study’s scope: a single-center observation during a bronchoscopy procedure, with the primary timeframe under 1 hour. They do not provide a comparative safety estimate because the study had no control group. They also should not be used to infer the result for leakage, which is a separate primary performance endpoint and is not reported in the registry record.

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

The record establishes that an observational performance evaluation of AuraOnce was registered as completed, with enrollment of 16 and a focus on placement and sealing during diagnostic flexible bronchoscopy under general anaesthesia. It specifies a primary question about leakage during the procedure and lists investigator ratings and placement-related secondary outcomes. The record also reports safety counts, including 0 participants affected by serious adverse events and 0 deaths in the listed group.

Those details describe the study’s scope and what it was designed to observe; they do not supply the primary or secondary outcome findings. The registry record does not report the number of participants with leakage, the signs of leakage, the rating distributions, or counts for correct placement and a folded tip. As a result, the posted information does not establish how often these performance outcomes occurred or how investigators rated the device.

The design also limits what any descriptive results could mean. With no control group, the study cannot show whether performance differs from another device or procedure. Because it is non-interventional and conducted at a single center in a defined procedural setting, observations would apply most directly to that setting rather than establish a result across other populations or clinical contexts. Investigator ratings describe assessed experience; they do not by themselves establish comparative effectiveness.

The safety figures are reassuring only in the narrow descriptive sense that the posted registry counts show no affected participants in the recorded serious or other adverse-event categories. They do not demonstrate absence of risk, establish complete event ascertainment, or answer the primary performance question. Likewise, the study’s completed status does not mean that every result is present in the registry.

Accordingly, the most defensible reading is that the registry describes a small, focused, uncontrolled evaluation but does not report the outcome results necessary to judge the observed insertion, seal, or leakage performance. No conclusion about comparative performance or causal effects follows from the information recorded.

14. Why This Trial Matters Statistically

This study illustrates a distinction central to clinical statistics: a registry can describe a clear measurement question without reporting the observations needed to answer it. The primary endpoint is specific in broad form—a yes/no assessment of leakage during a procedure—but its result is not reported in the registry record. Without the count and the number assessed, readers cannot quantify the event frequency or its precision.

The design is equally important. Prospective observation can collect information in the intended clinical setting, and the listed measures span event occurrence, investigator ratings, and placement observations. But a non-controlled evaluation answers a descriptive question, not a comparative one. If results were available, they could characterize recorded performance in this setting; they could not isolate a difference attributable to the device relative to an alternative.

The record also makes clear why different outcome types should not be conflated. A performance endpoint about leakage is not interchangeable with serious adverse-event counts. Investigator ratings on ordered scales have different interpretation needs from yes/no outcomes. Each requires a clear denominator and transparent reporting of how observations were summarized.

Finally, the record lists 6 outcome measures but 0 analyses. This makes the distinction between registering outcomes and reporting results especially visible. Statistical interpretation depends not only on which outcomes were named, but also on complete outcome values, analysis populations, missing-data handling, and methods. Those details are not reported in the registry record. The example therefore underscores that design descriptions and safety counts, however useful, cannot substitute for transparent reporting of the primary endpoint.

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 most consequential limitation for interpretation is that the primary leakage result is not reported in the registry record. Secondary outcome results are also absent. Without event counts, rating distributions, and endpoint-specific denominators, the intended performance assessment cannot be quantitatively evaluated or independently checked.

The study is non-controlled and non-interventional. There is no comparator group, so any observed performance would be descriptive rather than a comparative estimate. The record does not state allocation, and there is no randomized comparison described. The single-center setting in Denmark and the specified bronchoscopy context further limit how broadly observations could be generalized.

Enrollment is recorded as 16, while the brief description gives a planned range of 15 to 20 adults. The record does not report whether all enrolled participants contributed data to every measure or explain any differences between enrollment and outcome-specific assessment. Missing observations, exclusions, and handling of incomplete ratings are not reported. These gaps prevent assessment of outcome completeness.

Several measures rely on investigator evaluation using 5-point scales. The registry lists the scale labels but does not report additional scoring guidance, assessor training, blinding, or checks on agreement between evaluators. These procedures may affect how ratings are interpreted, but their conduct cannot be determined from the record. Likewise, the leakage definition is presented as yes/no with signs entered if present, but additional criteria for identifying leakage are not reported.

The observation covers one bronchoscopy procedure, with a primary timeframe under 1 hour. It does not describe longer-term outcomes. The record also does not report a statistical analysis plan, sample-size justification, multiplicity approach, or defined analysis populations. These limitations are specific to what is documented; they should not be taken as proof that unreported procedures were not carried out.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: AuraOnce Performance Observation — NCT04128527.
• Registry record last updated 2021-11-03; status last verified 2021-08.
• Results first posted 2021-11-03.
• 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

The registry identifies NCT04128527 as AuraOnce Performance Observation, sponsored by Ambu A/S, with status COMPLETED. The study began on 2019-10-09 and reached primary completion on 2019-11-05. Enrollment is recorded as 16.

It was a prospective, single-center, non-controlled, non-interventional evaluation in Denmark of laryngeal-mask placement in adults undergoing diagnostic flexible bronchoscopy under general anaesthesia. The primary outcome was the number of participants with leakage observed during the procedure, described as under 1 hour. Listed secondary outcomes include investigator ratings of insertion, seal, and overall performance, plus correct placement and a folded mask tip.

The record lists 6 outcome measures and 0 analyses. It does not report the primary or secondary outcome results, endpoint-specific denominators, or analysis methods. The safety record lists 0 participants affected by serious adverse events, 0 deaths, and 0 affected by other adverse events among 16 at risk in each listed category.