Alternative Sedation During Bronchoscopy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Alternative Sedation During Bronchoscopy (NCT01158820), a randomized phase 4 study. The primary outcome is Decreased Minute Ventilation.

2. Clinical Question

The clinical comparison is therefore between two sedation strategies, not between sedation and no sedation. Both arm descriptions include fentanyl and midazolam, though their use differs: they are listed as loading and demand medications in the placebo arm, and as demand medications in the dexmedetomidine-ketamine arm. The registry record does not give actual medication-use amounts or a detailed account of how demand dosing was administered. It also does not report a separate primary endpoint for procedural compliance. The primary endpoint and the secondary outcomes should therefore be read as distinct measures of the trial question rather than as interchangeable evidence about all aspects of sedation.

3. Trial Design

The registry identifies this as a randomized, placebo-controlled, parallel-group phase 4 trial with triple masking and concealed allocation described in the official title. The record lists 50 enrolled participants, with 25 in each of the two posted arms. The trial status is completed. The listed start was 2010-06, and the primary completion was 2012-05. The sponsor was the University of Pennsylvania.

The intervention arm was titled Dexmedetomidine and Ketamine. Its listed regimen included dexmedetomidine and ketamine loading and maintenance, plus midazolam, fentanyl, and Benadryl on demand. The placebo arm included midazolam and fentanyl loading, with midazolam, fentanyl, and Benadryl on demand. The record does not explain the placebo’s composition or give medication doses, administration schedules, or details of adherence.

The primary measure was collected during the bronchoscopy procedure only, whose reported average duration was 58.5 minutes. The measure was normalized to an initial baseline minute ventilation estimate obtained using calibrated respiratory impedance plethysmography bands. Values exceeding 100% of baseline were excluded because the record says they typically reflected hyperpnea after airway obstruction was relieved by chin lift or jaw thrust.

Other design details, including eligibility criteria, recruitment setting, the allocation procedure, masking procedures, and the planned analysis population, are not reported in the registry record. A sample-size justification, planned interim analyses, and a detailed statistical analysis plan are also not reported in the registry record. Randomization and masking describe important design features, but the registry information alone does not establish how completely these procedures were implemented or whether all randomized participants contributed to each 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 Decreased Minute Ventilation, measured over During the bronchoscopy procedure only, 58.5 minutes average.

The primary endpoint is minute ventilation during bronchoscopy expressed relative to an initial baseline estimate. Minute ventilation describes the volume of air moved in and out of the lungs over time. Expressing each measure as a percentage of baseline makes it possible to describe ventilation in relation to a participant’s own starting level rather than only as an absolute volume. The registry record identifies the summary as a median with inter-quartile range.

The baseline was estimated using calibrated respiratory impedance plethysmography bands. The record says that values above 100% were excluded because they typically occurred during hyperpnea after relief of airway obstruction by chin lift or jaw thrust. This rule defines which observations contribute to the endpoint: the posted measure does not include those periods of ventilation above baseline. It is therefore a measure of ventilation under the record’s specified exclusion rule, not an unrestricted summary of every recorded value during the procedure.

Minute ventilation is relevant to the stated concern about respiratory depression during procedural sedation. It is not, by itself, a complete account of respiratory safety or of the quality of sedation. The record does not report a threshold defining clinically important depression, nor does it report the endpoint’s measurement frequency or participant-level missingness. The average procedure timeframe was 58.5 minutes. The posted arm summaries are 0.736 for placebo and 0.764 for dexmedetomidine and ketamine. The record lists accompanying values of 0.592 to 0.848 and 0.592 to 0.891, respectively, but the meaning of those bounds is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The trial is described as randomized, parallel-group, placebo-controlled, and triple-masked. Random allocation is intended to make treatment assignment independent of participant characteristics, on average. Concealed allocation is intended to prevent knowledge of the next assignment during enrollment. Masking is intended to reduce the influence of treatment knowledge on care, measurement, or assessment. These are general methodological purposes; the registry record does not describe the procedures used to implement them or report checks of masking.

What does the primary summary represent?

The primary endpoint is summarized using medians and an inter-quartile range. A median is the midpoint of ordered observations: half lie on either side, subject to ties. It can describe a typical value while being less affected by extreme observations than a mean. The inter-quartile range describes the span between the middle portions of a distribution. The arm records contain values and lower and upper bounds, but those bounds are not explicitly identified as the inter-quartile range; their precise meaning is not reported in the registry record. It is therefore important not to treat them as a between-arm confidence interval.

Minute ventilation was normalized to baseline. Normalization can make a measure easier to compare across people whose initial values differ, but it changes the scale of interpretation: these values are relative to baseline rather than absolute ventilation volumes. The stated exclusion of values above 100% removes periods the record characterizes as hyperpnea after airway obstruction was relieved. Exclusions can affect a distributional summary, so the rule is part of the endpoint definition rather than a minor reporting detail. The registry does not report how many observations were excluded or how missing measurements were handled.

How should the Wilcoxon result be understood?

The Wilcoxon rank-sum test, also called the Mann-Whitney test, is a nonparametric method for comparing two independent groups. In general, it uses the ordering of observations rather than requiring a normal distribution or comparing means directly. Its interpretation depends on the distributions and assumptions; it is not automatically a test of a median difference. A simple location-shift interpretation may be reasonable only under additional conditions, which are not documented in the registry record.

The record reports this method and p < 0.001, while the analysis result is labeled “Mean Difference (Net)” and recorded as 0.028. The primary arm summaries, by contrast, are medians. The record does not explain the relationship among the test, the reported result label, and the medians, and it provides no confidence interval for the analysis. The statistical meaning of the sponsor’s reported estimate should therefore be kept distinct from a direct median contrast. The p-value does not supply an effect-size interval or a measure of clinical importance.

Why does over-dispersion matter?

Over-dispersion is a general issue for count outcomes: it occurs when variability exceeds what a statistical model assumes. If a model ignores over-dispersion, standard errors can be too small and tests can appear more conclusive than warranted. This concern does not define the primary analysis in this trial, which is a continuous, normalized endpoint analyzed with a rank-based test. The registry record does not report a count model or an over-dispersion assessment. The general concept is relevant to understanding statistical methods, but it should not be taken to mean that over-dispersion was present in this trial.

What do confidence intervals and p-values add?

In general, a confidence interval communicates uncertainty around an estimated effect, including the range of values reasonably compatible with the data under the method used. A p-value instead summarizes how unusual the observed data, or more extreme data, would be under a specified null model. Neither alone states whether an effect is clinically important. For the primary comparison, the registry does not report a confidence interval. The analysis p-value is reported as p < 0.001, but the record does not provide a full analysis specification or identify a confidence level for an effect interval.

For the secondary comparison of conversion to general anesthesia, the posted recalculation includes a risk difference and interval, as well as an unadjusted p-value. The risk difference is a difference in observed event risks between groups; its interval conveys uncertainty around that contrast under the method used for the recalculation. An unadjusted p-value does not account for the fact that multiple outcomes may be examined. The trial’s statistical plan for secondary analyses and multiplicity is not reported in the registry record, so these results are best treated as exploratory rather than as a confirmatory family of tests.

How should planning calculations be separated from trial results?

Planning calculations are illustrations of the sample size that could be needed under stated assumptions. They are not a measure of the trial’s observed power, and they do not establish that the trial was designed with those assumptions. The registry record gives an illustration based on the observed secondary effect, two-sided significance level 0.05, equal allocation, and a normal approximation. It considers planning for 100%, 75%, and 50% of the observed effect. The record explicitly distinguishes this illustration from the trial’s own design. Its sample-size justification is not reported in the registry record.

In general, planning estimates depend on the effect selected, variability assumptions, significance level, desired power, and analysis method. Because the illustration uses an observed effect, it should not be read as an independent estimate of the effect expected before the trial. The record does not establish that the assumed effect or method was part of the original protocol. These distinctions matter when readers assess whether the enrolled sample was intended to provide a particular level of precision.

What analysis details remain unknown?

The registry record does not report whether analyses followed intention-to-treat principles, how protocol deviations were handled, whether outcome assessors were masked, or how missing endpoint measurements were treated. It does not report pre-specified subgroup analyses or interim looks at the data. Without these details, a reader cannot fully assess whether the posted analyses match a pre-specified plan, whether all randomized participants were included as assigned, or how sensitive results may be to missing data and exclusions. These are uncertainties in the record, not evidence that any particular procedure was or was not used.

10. Analyses Reported by the Sponsor

The registry reports a sponsor analysis using the Wilcoxon (Mann-Whitney) method, with p < 0.001. The analysis entry labels its result “Mean Difference (Net)” and records 0.028. The primary arm summaries are medians, 0.736 for placebo and 0.764 for dexmedetomidine and ketamine. The record does not explain how the reported analysis estimate is defined or how it relates to the median summaries. It also does not report a confidence interval for the sponsor’s primary analysis.

The recalculation information does not flag a discrepancy for this trial. Accordingly, the sponsor’s reported analysis remains the primary inferential result to describe; any recalculation should not replace it. The reported p-value is a statement about the sponsor’s test under its analysis, not a confidence interval or a direct measure of clinical importance. The lack of a confidence interval and the unclear alignment between the “Mean Difference (Net)” label, the rank-based test, and the median endpoint limit how precisely the effect can be interpreted from the registry record.

In general, a re-calculation from posted summary data may be useful as a check, but it can rely on a different estimand or assumptions from the original analysis. No recalculated primary effect estimate is posted for this endpoint. The secondary conversion-to-general-anesthesia calculation is a separate, unadjusted analysis and should not be presented as a verification of the sponsor’s primary test. The statistical analysis plan and any additional sponsor analyses are not reported in the registry record.

11. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when researchers examine multiple outcomes, groups, time points, or analyses. If each test is treated as an independent opportunity to find a statistically unusual result, the probability of at least one such result can rise across the set. This general concern is especially relevant when a trial reports several secondary outcomes in addition to its primary endpoint. Appropriate handling depends on the intended claims and analysis plan; it may involve a prespecified hierarchy or an adjustment to the testing procedure.

The registry lists five secondary outcomes, but a multiplicity strategy, testing hierarchy, or confirmatory status for those outcomes is not reported in the registry record. The posted conversion-to-general-anesthesia p-value is unadjusted. It should therefore be read as a nominal result for that comparison rather than as evidence that accounts for the full set of outcomes. Results for the other listed secondary outcomes are not reported in the registry record, which also limits assessment of the full outcome pattern.

Missing-data handling is another unresolved issue. The primary endpoint description explains that values exceeding 100% of baseline were excluded, but the number of such values, the number of missing measurements, and the reasons for missingness are not reported in the registry record. The record does not say whether missing observations were imputed, whether participants with incomplete measurements were excluded, or whether sensitivity analyses were performed. These details matter because the analyzed observations may not fully represent all randomized participants if data are incomplete or exclusions are related to the outcome.

The analysis populations are not reported in the registry record. It is therefore unclear whether the primary analysis included all randomized participants according to assigned group, only participants who completed the procedure, or another defined population. The record also does not report protocol deviations or how they were handled. A sample-size justification, interim analyses, and a detailed statistical analysis plan are not reported in the registry record. These omissions prevent a full evaluation of pre-specification, selective reporting, and the relationship between the posted analyses and the planned analyses. They are limits on what can be concluded from the record, not proof that particular procedures were absent.

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 registry reports serious adverse events for the two arms, with 25 participants at risk in each. It records zero serious adverse events in the placebo arm and zero in the dexmedetomidine-and-ketamine arm. It also records zero other adverse events in each arm and zero deaths in each arm. No serious adverse-event terms are listed.

These figures describe what was entered in the registry for the reported risk groups. Zero reported events does not establish that an intervention is free of risk, particularly when the record does not provide a detailed adverse-event collection method, follow-up duration, event definitions, or a fuller account of non-serious events. The trial enrolled 50 participants overall, but adverse-event observations are reported by arm; group figures should be read as such and not extended beyond the recorded population and observation period.

The safety entries also do not address the primary endpoint directly. Minute ventilation, desaturation outcomes, and recorded adverse events are distinct measures, and the registry does not provide enough detail to infer that one can substitute for another. A reader should treat the adverse-event counts as a limited description of events recorded in this trial, not as a definitive comparison of the full safety profiles of the sedation strategies.

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

The registry describes a randomized comparison of dexmedetomidine-ketamine adjunct sedation with placebo alongside fentanyl-midazolam sedation during bronchoscopy. Its primary endpoint summarizes normalized minute ventilation during the procedure, after excluding values exceeding 100% of baseline under the stated rationale. The posted medians are 0.736 for placebo and 0.764 for dexmedetomidine and ketamine. The registry also reports a Wilcoxon (Mann-Whitney) analysis with p < 0.001, but the entry labels its estimate “Mean Difference (Net)” and does not provide a confidence interval or clarify the connection between that label and the median summaries.

Those details describe the reported data and analysis; they do not, by themselves, establish the size or clinical importance of an effect. A p-value is not a probability that the intervention works, nor does it indicate how likely the result is to recur. The absence of a reported confidence interval for the primary analysis leaves its precision difficult to assess. The record also does not define a threshold for clinically important change in minute ventilation.

The primary endpoint is not a comprehensive measure of respiratory safety, medication use, procedural compliance, or patient experience. The registry lists secondary outcomes in some of those areas, but results are not reported for all of them. The one posted secondary comparison is unadjusted, and the record does not describe a multiplicity plan. The safety entries record no serious adverse events, other adverse events, or deaths in either group, but these counts should not be interpreted as establishing absence of risk.

The study record therefore supports a narrow reading: it reports a particular ventilation measure and a sponsor test for a randomized bronchoscopy comparison. It does not establish how the result applies to other procedures, populations, settings, or sedation regimens. Further information about the analysis population, missing data, endpoint precision, and prespecified statistical plan would be needed for a fuller assessment. No treatment recommendation follows from these registry results alone.

14. Why This Trial Matters Statistically

This trial raises several statistical issues that are common in clinical research. First, the endpoint is relative to a participant-specific baseline and is summarized by a median. That choice makes the result a distributional summary of normalized ventilation rather than an absolute volume or a simple average. Understanding the measurement scale is essential before interpreting the arm summaries.

Second, the record’s endpoint rule excludes values above 100% of baseline because they are described as reflecting hyperpnea after airway obstruction was relieved. This illustrates how a clinically motivated rule can define the estimand: the resulting summary concerns observations retained under the rule, not every recorded ventilation value. Without counts of excluded or missing observations, readers cannot assess how much the rule affected the analysis.

Third, the reported inferential method and result label do not align transparently with the endpoint summary. A Wilcoxon rank-based test is reported alongside medians, while the estimate is labeled “Mean Difference (Net).” The registry does not explain the estimand or report a confidence interval. This is a useful reminder that p-values, effect estimates, and descriptive summaries answer different questions and should be checked for consistency in their definitions.

Finally, the record lists multiple secondary outcomes but does not report an analysis plan for multiplicity. An isolated unadjusted secondary result carries more uncertainty when considered among several outcomes, particularly when results for other listed outcomes are unavailable. The planning illustration is explicitly based on the observed effect and is not the trial’s own design justification. Together, these features show why careful reading of endpoint definitions, analysis labels, uncertainty intervals, missing-data procedures, and multiplicity plans is necessary for sound interpretation.

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 registry record provides limited detail for assessing how the trial was conducted and analyzed. Eligibility criteria, participant characteristics, setting, medication doses, dosing procedures, and the implementation of allocation concealment and masking are not reported in the registry record. The official title describes concealed allocation and triple masking, but operational details are not given.

The primary endpoint’s measurement description includes a rule excluding values above 100% of baseline. The count of excluded values, the frequency of measurement, missing observations, and reasons for incomplete data are not reported in the registry record. The bounds listed with the arm medians are also not identified by type, so their role in expressing uncertainty cannot be determined from the record.

The reported primary analysis has no confidence interval, and the record does not explain the relationship between the Wilcoxon test, the “Mean Difference (Net)” label, and the median summaries. The analysis population, handling of protocol deviations, prespecified analysis plan, and any interim analyses are not reported in the registry record. The record also does not report a multiplicity strategy for the secondary outcomes. These gaps restrict assessment of precision, robustness, and whether the analyses followed a prespecified plan.

Finally, results for several listed secondary outcomes are not reported in the registry record, limiting comparison across respiratory, satisfaction, and procedural measures. The adverse-event entries are brief and do not describe collection procedures or follow-up. The planning illustration uses the observed effect and is not documented as the trial’s original sample-size rationale. These are limitations of the available registry information; they do not establish what may have been reported elsewhere or what procedures may have been used.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Alternative Sedation During Bronchoscopy — NCT01158820.
• Registry record last updated 2019-02-26; status last verified 2019-02.
• Results first posted 2018-10-31.
• 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

NCT01158820, titled “Alternative Sedation During Bronchoscopy,” is listed as a completed, randomized, placebo-controlled, parallel-group phase 4 trial sponsored by the University of Pennsylvania. The official title describes concealed allocation and triple masking. The record lists enrollment of 50, with 25 participants in each posted arm.

The comparison was dexmedetomidine and ketamine alongside on-demand midazolam and fentanyl versus placebo alongside midazolam and fentanyl loading and demand medications. The primary endpoint was median minute ventilation as a percentage of baseline during bronchoscopy, with values above 100% excluded under the stated rule. The registry reports a Wilcoxon (Mann-Whitney) analysis with p < 0.001, but does not provide a confidence interval or clarify the reported estimate’s relationship to the median summaries.

Five secondary outcomes are listed, with a numerical comparison posted for conversion to general anesthesia. The registry also records zero serious adverse events, other adverse events, and deaths in each arm. Details about missing data, analysis populations, multiplicity, and the statistical analysis plan are not reported in the registry record.