This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Esophageal Manometry During Recovery From Anesthesia: Pilot Study (NCT02661386), a na na study. The primary outcome is Total Time of the Return of Normal Pharyngoesophageal Function.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02661386 |
| Phase | NA |
| Condition | Motility Function |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 32 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of California, San Francisco |
| Results posted | Yes |
2. Clinical Question
Population
The study included 32 patients: 18 women and 14 men, ages ranging from 20 to 76 years. The registry record identifies motility function as the condition of interest. The clinical setting was recovery after general anesthesia, when the study aimed to observe the return of pharyngoesophageal function.
Intervention
The intervention was a motility procedure using a manometry device. The arm description says the procedure would be performed during the last 10 minutes of subjects waking up from anesthesia. The primary outcome focused on the time from withdrawal of general anesthesia until normal pharyngoesophageal function returned, assessed up to 40 minutes.
Comparator
There was no separate control group or active comparator. The registry identifies a single-group model and lists allocation as not applicable. Accordingly, the study is not a randomized comparison, and its design does not estimate a difference between the device procedure and another procedure, usual care, or no procedure.
Primary question
The primary question was how long it took for normal pharyngoesophageal function to return after general anesthesia was withdrawn. The stated objective was to determine the timing of this return. The registry record does not report the observed time, its full range, or a statistical estimate of the outcome, so the clinical question is specified but its numerical answer is not reported in the registry record.
3. Trial Design
This was a completed pilot study, titled “Esophageal Manometry During Recovery From Anesthesia: Pilot Study.” The registry lists the study as single group, with allocation not applicable and no masking. The sponsor was the University of California, San Francisco. The listed phase is not applicable. The study began in 2016-01, reached primary completion on 2019-03-05, and is recorded as completed.
The enrollment was 32. The described population comprised 18 women and 14 men, with ages ranging from 20 to 76 years. The intervention was a device-based motility procedure. The arm description states that manometry would be performed during the last 10 minutes of subjects waking up from anesthesia. These details describe the planned measurement context; they do not establish that every participant completed the same measurement or that the procedure was performed identically for each person.
The primary outcome was the total time, in minutes, from withdrawal of general anesthesia until return of normal pharyngoesophageal function. The assessment period was up to 40 minutes. The outcome was specified as a mean with full range as its dispersion measure. A secondary outcome was the number of participants with normal pharyngoesophageal function. The registry lists two outcome measures but does not report their observed results.
Because the study has no comparator group, it can describe the intended observation in this cohort but cannot provide a randomized between-group estimate. The registry record does not report further details about eligibility criteria, the measurement protocol, treatment or anesthesia procedures, or how participants entered the study. It also does not report a protocol-specific sample-size justification or a statistical analysis plan.
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
| Stage | Manometry Device |
|---|---|
| STARTED | 32 |
| COMPLETED | 32 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: Thirty-two patients, 18 women and 14 men, ages ranging from 20 to 76 years were studied.
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.
| Characteristic | Unit | Manometry Device |
|---|---|---|
| Participants analysed | 32 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 27 |
| Age, Categorical: >=65 years | Participants | 5 |
| Sex: Female, Male: Female | Participants | 18 |
| Sex: Female, Male: Male | Participants | 14 |
| Race and Ethnicity Not Collected | Participants | — |
6. Primary Endpoint
The registry lists the primary outcome as Total Time of the Return of Normal Pharyngoesophageal Function, measured over From withdrawal of general anesthesia until the return of normal pharyngoesophageal function, assessed up to 40 minutes..
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Full Range |
| Unit | minutes |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the time from withdrawal of general anesthesia until normal pharyngoesophageal function returns, measured in minutes and assessed up to 40 minutes. It targets the timing of a physiological event during recovery rather than a comparison of treatment outcomes. The study description presents manometry as the means of assessing esophageal function, while the stated primary objective is to determine when normal pharyngoesophageal function returns.
The registry specifies a mean as the summary measure and the full range as the measure of dispersion. In general, the mean describes the average observed time, while the full range describes the lowest and highest observed values. The range can indicate how widely observations vary, but it does not show the distribution of values between its endpoints. Neither a mean nor a range is reported in the registry record, so the endpoint's observed timing and variability cannot be assessed from the record.
The assessment window is limited to up to 40 minutes. The registry does not state how a participant whose normal function was not observed within that window would be handled in the analysis, or whether any such cases occurred. Those details matter when interpreting a time-based outcome because the observed time may not be known for every participant. The endpoint is clinically framed around recovery, but its numerical results and the operational criteria for normal function are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record defines a focused measurement question: the time from withdrawal of general anesthesia to return of normal pharyngoesophageal function. It identifies 32 participants and specifies that the outcome would be summarized by a mean and full range. However, the observed primary outcome value is not reported in the registry record. The number of participants with normal pharyngoesophageal function, listed as a secondary outcome, is also not reported. Consequently, the record does not provide a numerical estimate of recovery timing or the observed frequency of that secondary outcome.
Without the observed mean and range, readers cannot determine the typical recorded time, the spread of recorded times, or whether there were unusually early or late observations. Without a confidence interval or another uncertainty estimate, the precision of a population-level estimate cannot be evaluated. Such uncertainty is important even when a sample mean is available: it distinguishes an estimate from the range of values that could plausibly be compatible with the study observations under a specified method. No such interval or method is reported in the registry record.
The single-group design also sets a limit on interpretation. The observations could describe what was measured among participants undergoing this procedure in the stated recovery setting, but the design does not include a concurrent comparison group. It therefore does not estimate a difference against an alternative measurement approach or another recovery strategy. The absence of randomization is not a flaw in a descriptive pilot question by itself; it does mean that comparative treatment conclusions are not supported by this design.
The study's background describes a proposed relationship between returning pharyngoesophageal activity and awakening from anesthesia. That rationale is not itself evidence that the measured function predicted a safe time for airway-related decisions. The registry record does not report an analysis relating the manometry assessment to airway outcomes, tube removal, aspiration, or other clinical events. Nor does it report validation of a verbally stimulated swallowing sequence against the primary endpoint.
The adverse-event figures list 32 participants at risk, with zero serious adverse events, zero other adverse events, and zero deaths. Those figures describe recorded events in the registry entry; they do not supply the missing primary endpoint results or establish that every possible harm was assessed or excluded. Overall, the record specifies the intended observation, but it does not provide the results needed to quantify the primary endpoint, its precision, or its relation to clinical decisions.
9. Statistical Methods Explained
The statistical interpretation begins with the type of question being asked. This study is a single-group pilot focused on the time to return of a function after withdrawal of general anesthesia. It is not a randomized comparison. For a single-group endpoint, the central descriptive questions concern the observed values, their summary, and their variability. The registry specifies the mean and full range for the primary endpoint, but it does not report the values needed to interpret either summary.
What does a mean describe?
In general, the arithmetic mean summarizes a set of measurements by their average. It can be a useful description of a time outcome when the values are reasonably represented by an average. However, the mean does not reveal the shape of the distribution. Different patterns of individual times can produce the same mean, and unusually large or small values can influence it. The registry names the mean as the primary summary but provides no observed mean. The mean therefore cannot be discussed as a result for this study.
The full range is the interval from the smallest observed value to the largest observed value. In general, it gives a direct sense of the most extreme observations, but it is sensitive to those extremes and does not show how densely observations cluster. A range alone cannot show whether values are concentrated near the mean or spread throughout the interval. Although the registry specifies full range as the dispersion measure, neither endpoint of the range is reported in the registry record.
Why does uncertainty matter?
In general, a confidence interval communicates uncertainty around an estimate under a stated statistical method and assumptions. It is not the range of individual participant values. An interval around a mean and the full range of observed times answer different questions: the former concerns uncertainty in an estimated quantity, while the latter describes observed extremes. The registry record does not report a confidence interval, standard error, or other uncertainty estimate for the primary endpoint. Without the observed summary and uncertainty measure, readers cannot judge how precisely the cohort estimates the timing of return.
Precision is distinct from whether an effect is clinically important. A narrow interval can indicate a more precise estimate, while a broad interval can leave substantial uncertainty; neither alone establishes clinical importance. Here, there is no numerical primary estimate or interval to evaluate. The word “pilot” in the study title does not supply a result, a precision target, or a sample-size rationale. A protocol-specific justification for enrollment of 32 is not reported in the registry record.
What can a single-group design estimate?
A single-group study can describe measurements made among its participants, subject to the quality and completeness of those measurements. It cannot estimate a contrast with a control group that was not enrolled. General comparisons with external experience would require information about the other population and methods, and such a comparison is not described in the registry record. The study lists allocation as not applicable and masking as none. These design details should be considered when judging the potential for measurement or observer influences; the record does not describe safeguards or procedures for addressing them.
The sample-size planning assumptions described for planning illustrations use a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. Those are planning assumptions, not a description of this trial's single-group design. They should not be read as a protocol justification, an observed-power calculation, or evidence that the study had a particular probability of detecting an effect. The record does not report the trial's own sample-size justification. Since the primary result is absent, the observed effect underlying such illustrations is also not available for independent review.
In general, a normal approximation can simplify calculations by using properties of the normal distribution. Its suitability depends on the statistical quantity and the data pattern. Equal allocation between two arms is an assumption for a comparative design, whereas this study is single group; therefore that assumption does not describe how participants were allocated in this pilot. A stated significance level is a design or analysis convention, not an outcome. The registry record does not report a trial-specific inferential test, its hypotheses, or an analysis estimate.
How should a time-based outcome be understood?
A time-to-event outcome concerns the time until a defined event occurs. General methods for such outcomes may account for participants whose event is not observed during follow-up, but the appropriate method depends on how the event and follow-up are defined. The primary endpoint has a maximum assessment period of up to 40 minutes, but the registry record does not state how unobserved returns of normal function were handled, whether follow-up times differed, or whether any observations were incomplete. It also does not report whether a time-to-event method was used. No such method should be attributed to this trial from the endpoint description alone.
Interpretation also depends on how “normal pharyngoesophageal function” was operationally defined and measured. The record states the endpoint and identifies manometry as the procedure, but the detailed criteria, measurement schedule, and rules for determining return are not reported in the registry record. These details influence reproducibility and may affect the recorded endpoint time. The available information therefore supports describing the intended measure and its summary format, but not reconstructing the analysis or asserting the reliability of the measured times.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists two outcome measures: the primary measure of total time until return of normal pharyngoesophageal function and a secondary measure counting participants with normal pharyngoesophageal function. It lists no analyses. A multiplicity strategy for interpreting multiple outcomes or repeated statistical tests is not reported in the registry record. The record also does not state whether additional outcomes or subgroup analyses were planned. Without an analysis plan, it is not possible to determine how the investigators intended to control the chance of false-positive findings across multiple tests, if inferential tests were planned.
The registry record does not report the observed results for either listed outcome. It also does not state how missing or incomplete measurements were handled, whether any participants were excluded from an analysis, or what analysis population was used. These are distinct issues: missing-data methods concern unavailable measurements, while analysis-population rules specify which participants contribute to an analysis. Neither can be inferred from the enrollment count alone.
Because the primary endpoint was assessed up to 40 minutes, the handling of a participant whose function did not return within the assessment period would be particularly relevant. The record does not say whether such a participant would be counted as not having an observed return, treated as having an incomplete measurement, or handled by another rule. It does not report whether this situation occurred. Likewise, the registry does not describe how missing manometry measurements, withdrawals, or other deviations were treated.
In general, transparent reporting of outcome definitions, analysis populations, and missing-data decisions helps readers assess whether conclusions could depend on analytic choices. Those details are not reported in the registry record, so the analysis cannot be reconstructed from the listed design and outcome descriptions.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Manometry Device | 0 | 32 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Manometry Device | 0 of 32 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Manometry Device | 0 of 32 |
The registry lists 32 participants at risk in the Manometry Device group. It records zero serious adverse events, zero other adverse events, and zero deaths. These are the recorded counts in the registry entry. They should be read as event counts for this group, not as a complete characterization of every possible safety outcome.
A zero count means that no event in the listed category was recorded in the registry result; it does not establish that the underlying risk is zero. In general, safety estimates are uncertain when based on a limited number of participants, and interpretation depends on the definitions used, the observation period, completeness of follow-up, and how events were collected. The registry record does not report detailed event definitions, a separate safety follow-up period, or further methods for event ascertainment.
The listed counts do not indicate whether every participant had complete safety follow-up or whether events outside the recorded categories were evaluated. No serious adverse event terms are listed. The figures should therefore be interpreted narrowly as the posted counts, rather than as proof that the procedure has no safety risks. They also do not address the primary endpoint, whose numerical result is not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The record establishes that investigators planned a pilot observation of pharyngoesophageal function during recovery from general anesthesia. It identifies the primary measure as elapsed time from withdrawal of general anesthesia until normal function returned, assessed up to 40 minutes, and specifies a mean and full range as summaries. It also describes a manometry procedure during the last 10 minutes of waking up from anesthesia. These details clarify the intended question and measurement setting.
The record does not report the observed primary endpoint value, its range, or an uncertainty estimate. It therefore does not establish how quickly function returned in the studied participants or how much individual times varied. The secondary outcome count is also not reported. Without these results, no conclusion about the observed timing or proportion of participants with normal function can be drawn from the registry entry.
The study rationale discusses the importance of pharyngoesophageal reflexes and proposes that return of normal activity could correspond with awakening. A rationale is a reason to study a question, not a result demonstrating that the proposed relationship was observed. The registry does not report a validation analysis connecting manometry findings with airway safety, aspiration, removal of endotracheal tubes, or decisions about reversing anesthesia. It therefore does not establish that the measurement predicts a safe time for any clinical action.
The single-group design does not provide a treatment comparison. It cannot show whether the manometry procedure changes recovery, improves an outcome, or performs better than another assessment. The adverse-event counts are recorded as zero for serious events, other events, and deaths among 32 participants at risk, but those counts do not establish that all possible harms are absent. The appropriate interpretation is limited: the registry describes a completed pilot and its intended measures, while the numerical primary and secondary outcome results needed to assess what was observed are not reported in the registry record.
13. Why This Trial Matters Statistically
This trial illustrates an important distinction between a clearly framed research question and a fully interpretable result. The registry identifies a specific time-based endpoint, its units, the intended summary statistics, and the period over which assessment was planned. Those features allow readers to understand what investigators wanted to measure. But without the observed mean, full range, or other outcome results, the study's principal descriptive finding cannot be evaluated.
It also illustrates why design and analysis details matter for a pilot. A single-group study can be useful for describing the measurement context and generating questions for future research, but it does not estimate a randomized contrast. The registry identifies no comparator, and the stated sample-size planning assumptions involving equal allocation between two arms do not describe the actual single-group structure. Separating planning illustrations from trial design prevents a planning calculation from being mistaken for evidence about the study's ability to detect an effect.
The endpoint concerns return of a function over a bounded observation period. Such outcomes require clear event definitions and transparent handling of cases where the event is not observed within follow-up. The registry states that assessment was up to 40 minutes but does not report rules for incomplete observation or the handling of missing measurements. These omissions limit reproducibility and make it difficult to assess how the endpoint would be interpreted in all participants.
Finally, the trial's clinical rationale reaches beyond a physiological time measurement to potential decisions about airway-related care. Statistically, that connection requires evidence linking the measurement to the relevant clinical outcomes, not simply a plausible mechanism. The registry does not report those analyses. The example therefore shows why a physiological endpoint, a safety count, and a clinical decision claim are separate kinds of evidence, each requiring its own results and analysis.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The main limitation for interpreting this trial is that the registry record does not report the observed primary endpoint result. Although the endpoint is defined as time to return of normal pharyngoesophageal function and is to be summarized by a mean and full range, neither the mean nor the range is present. The secondary count of participants with normal function is also not reported. There is consequently no outcome estimate with which to assess the study's main descriptive question.
The single-group design has no concurrent comparator, so it cannot support a direct between-group comparison. The registry lists masking as none, and it does not describe procedures that might reduce measurement or observer influence. The details of eligibility, measurement frequency, criteria for normal function, and the procedure for identifying the return time are not reported in the registry record. These omissions constrain judgments about reproducibility and measurement consistency.
The assessment period was up to 40 minutes, but the registry does not explain the treatment of observations in which normal function was not recorded within that period. It does not report the extent of missing outcome data, withdrawals, analysis populations, or methods for handling incomplete measurements. No confidence interval or other uncertainty estimate is reported, and a protocol-specific sample-size justification is not reported in the registry record.
The clinical rationale refers to possible relevance for airway protection and decisions during recovery, but the registry does not report results linking the manometry endpoint to airway outcomes or clinical decisions. The safety counts are also limited to the categories listed and are not accompanied by detailed ascertainment or follow-up methods. These limitations concern what can be concluded from the registry entry; they do not establish that the study procedures or analyses were inadequate.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Esophageal Manometry During Recovery From Anesthesia: Pilot Study — NCT02661386.
- Registry record last updated 2026-08-20; status last verified 2026-07.
- Results first posted 2026-08-20.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT02661386 is a completed, single-group pilot study sponsored by the University of California, San Francisco. Enrollment was 32; the described participants included 18 women and 14 men, ages 20 to 76 years. The intervention was a manometry device procedure during the last 10 minutes of waking up from anesthesia. There was no comparator, and masking was listed as none.
The primary outcome was time from withdrawal of general anesthesia until return of normal pharyngoesophageal function, assessed up to 40 minutes and specified as a mean with full range. The secondary outcome was the number of participants with normal pharyngoesophageal function. Neither outcome result is reported in the registry record, and no analyses are listed. The adverse-event entry records zero serious events, zero other events, and zero deaths among 32 participants at risk. The record does not report a trial-specific sample-size justification, detailed missing-data methods, or an analysis plan.