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 Impact of Anesthetic Choice (Sevoflurane Versus Desflurane) on Airway Reflex Recovery in the Context of Antagonized Neuromuscular Block (NCT01199237), a randomized phase 4 study. The primary outcome is Recovery of Ability to Swallow After Neostigmine/Glycopyrrolate Antagonism of Rocuronium Paralysis..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01199237 |
| Phase | Phase 4 |
| Condition | Airway Reflexes, Protective, Recovery After Neuromuscular Block, Anesthetic Recovery |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 107 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of California, San Francisco |
| Results posted | Yes |
2. Clinical Question
The trial asks whether the choice of inhaled anesthetic is associated with recovery of a protective airway reflex after neuromuscular block has been reversed. Its central comparison is between sevoflurane and desflurane, with rocuronium used in both arms and reversal with neostigmine plus glycopyrrolate. The question concerns swallowing after patients become responsive to command, rather than simply whether they appear awake.
Population
Participants undergoing anesthesia with rocuronium and reversal by neostigmine plus glycopyrrolate. The primary outcome population consists only of participants judged by the clinician able to take the swallowing test (n=57).
Intervention
Sevoflurane, given with rocuronium and neostigmine plus glycopyrrolate reversal.
Comparator
Desflurane, also given with rocuronium and neostigmine plus glycopyrrolate reversal.
Primary question
At 2 minutes after the first response to command, how many participants can swallow water under the registry's assessment criteria?
The registry's rationale is that an appropriate response to command may not by itself establish recovery of protective airway reflexes. The description also raises the possibility that anesthetic choice and recovery from neuromuscular block could jointly affect pharyngeal function. These are motivations for the comparison, not findings from the posted results. The registry record does not report the arm-specific primary outcome counts or an estimated between-arm effect, so the clinical question cannot be answered from the posted primary endpoint results.
3. Trial Design
This is a Phase 4, randomized, parallel-group trial with triple masking. The registry lists enrollment of 107 and a completed status. The recorded start is 2010-08, and primary completion is 2012-08. The sponsor is University of California, San Francisco. The brief summary says the investigators planned to randomly assign 100 patients, while the registry enrollment field records 107; the record does not explain the relationship between those figures.
The two arms differ in the inhaled anesthetic: sevoflurane or desflurane. Both arm descriptions include rocuronium and reversal with neostigmine plus glycopyrrolate, with doses listed as 70 and 14 ug/kg. This common treatment context makes anesthetic choice the registered contrast of interest, although the record does not provide a full protocol or enough detail to assess every aspect of treatment delivery.
Random assignment can, in general, reduce systematic differences between groups at baseline, while masking can reduce the influence of treatment knowledge on care or outcome assessment. The registry identifies the trial as triple-masked, but does not identify the masked roles or describe how masking was maintained. Details of the randomization sequence, allocation concealment, and stratification are not reported in the registry record.
The primary outcome applies to participants judged by the clinician able to take the swallowing test, a subset recorded as n=57. That restriction is important when interpreting the endpoint: it is not described as an assessment of every enrolled participant. The record does not explain why other participants were not testable or how their outcomes were handled. It lists additional outcomes concerning time to first response to command, nausea and vomiting, and time to first ability to swallow, but their results are not included in the registry information summarized by the primary endpoint.
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.
Before assignment: Participation of the first 26 enrollees was considered a pilot to determine the feasibility of measuring the primary outcome at T1+5 minutes. The majority of participants were alert, and no meaningful analyses could be made. The study was modified to assess the primary outcome at T1 + 2 minutes, and 81 additional participants were recruited.
Overall Study
| Stage | Sevoflurane | Desflurane |
|---|---|---|
| STARTED | 41 | 40 |
| COMPLETED | 41 | 40 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Only participants judged by the clinician as able to take the test (n=57)
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 | Sevoflurane | Desflurane | Total |
|---|---|---|---|---|
| Participants analysed | 41 | 40 | 81 | |
| Age, Continuous | years | 45.3 (42.0 to 48.7) | 43.3 (40.2 to 46.5) | 44.3 (40.2 to 48.7) |
| Sex: Female, Male: Female | Participants | 41 | 36 | 77 |
| Sex: Female, Male: Male | Participants | 0 | 4 | 4 |
| Region of Enrollment: United States | participants | 41 | 40 | 81 |
6. Primary Endpoint
The registry lists the primary outcome as Recovery of Ability to Swallow After Neostigmine/Glycopyrrolate Antagonism of Rocuronium Paralysis., measured over At 2 minutes after response to command (T1)..
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of participants judged able to swallow after neostigmine/glycopyrrolate antagonism of rocuronium paralysis. The assessment was scheduled at 2 minutes after the first response to command, identified as T1. At that point, the participant was asked to swallow 20mL of water from a paper cup. A blinded observer judged swallowing using the passage of water to the posterior pharynx, with absence of pooling or drooling and absence of cough or gag as the stated criteria.
This endpoint is intended to assess a protective airway-related function during recovery, rather than relying only on a participant's apparent wakefulness or response to instruction. In general, a directly observed functional task can capture an aspect of recovery that a measure of alertness alone may not represent. The registry's rationale emphasizes that airway reflex recovery may not coincide with response to command; that rationale explains the choice of endpoint but does not establish that one anesthetic performs better.
The registered primary outcome population includes only participants judged by the clinician able to take the test (n=57). The registry record does not report how many in each randomized arm passed the assessment, the arm-specific denominators for this endpoint, or an estimated treatment contrast. Therefore, the definition and measurement procedure are available, but the primary result is not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the question and the endpoint, but it does not provide the primary outcome result needed to compare sevoflurane with desflurane. In particular, it does not report the number of participants who met the swallowing criteria in either arm, the corresponding endpoint denominators by arm, or a between-arm estimate. No confidence interval or p-value for the primary comparison is reported in the registry record. Without these results, the direction, size, and precision of any observed difference cannot be described.
The overall enrollment field records 107 participants. The primary outcome population is narrower: only participants judged able to take the test, listed as n=57. Those figures describe different parts of the record and should not be treated as interchangeable. The record does not explain which participants were excluded from the testable population, whether inability to undergo the test was related to recovery, or how this restriction was applied across arms. As a result, the endpoint population's relationship to all randomized participants is not fully clear.
For a binary outcome such as passing versus not passing a swallowing assessment, a between-group comparison would ordinarily be interpreted by looking at the event counts, denominators, and an estimate of the difference or another defined contrast, together with uncertainty. General statistical principle: an estimate describes the observed contrast in the study, while a confidence interval indicates the range of values compatible with the data under the method's assumptions. A p-value addresses compatibility with a specified null model; it does not measure clinical importance or establish that an effect is absent. None of those primary comparison results is reported in the registry record.
The trial's randomized design is relevant to interpretation because randomization is intended to make treatment groups comparable in expectation. That design feature does not replace examination of the actual outcome data, nor does it resolve concerns caused by missing or unavailable assessments. Masking is also relevant: a blinded observer judged the swallowing test, which may reduce the influence of knowledge of treatment on scoring. The registry does not report enough detail to evaluate masking of other roles or the success of masking.
The serious adverse event entries list 0 affected participants among 41 at risk in the sevoflurane group and 0 among 40 at risk in the desflurane group. Other adverse events are also listed as 0 among 41 and 0 among 40, respectively. These entries describe the registry's safety counts; they do not supply a comparative estimate or establish that no events occurred outside the recorded categories or observation period. Deaths are not reported in the registry record. Overall, the posted information supports a description of the study design, endpoint definition, and listed safety counts, but not a conclusion about the primary swallowing comparison.
9. Statistical Methods Explained
Interpreting a clinical trial starts with the design and the outcome definition, then asks what data and analysis are available for the registered comparison. Here, the registry describes randomized allocation to two parallel arms, with the inhaled anesthetic differing between them and rocuronium reversal included in both. It identifies a binary primary outcome based on whether a participant meets the swallowing assessment criteria. The registry record does not report the arm-specific primary outcome counts or an inferential analysis for that endpoint, so the usual comparison cannot be reconstructed from the listed information.
What does a binary endpoint represent?
A binary endpoint classifies each assessed participant into one of two states, such as meeting or not meeting the stated criterion. In general, an event count needs a denominator to be interpretable: the count alone does not show how frequently the event occurred in the group. A comparison can then be expressed using an appropriate contrast, such as a difference in event proportions or a relative measure. The contrast must match the analysis plan and the endpoint's definition. The registry reports the endpoint as a number of participants and identifies the testable population as n=57, but does not give the event counts and arm-specific denominators needed for that comparison.
General statistical principle: uncertainty depends on the amount and pattern of information, not just on whether a test crosses a conventional threshold. A confidence interval communicates uncertainty around an estimated contrast and can include values consistent with different degrees or directions of effect. A narrow interval indicates greater precision than a wide interval, subject to the method and assumptions. Without a reported estimate and interval, precision for the primary comparison cannot be assessed. A missing p-value should not be interpreted as evidence that the groups are identical.
Why does the testable population matter?
The primary assessment was limited to participants judged by the clinician able to take the test. This is a defined subset, not automatically the same as every randomized participant. General statistical principle: restricting analysis to people with an observed outcome can affect interpretation if the ability to be assessed is related to treatment assignment, recovery, or the outcome itself. The registry does not report reasons for unavailability, arm-specific assessment rates, or a missing-data analysis. It is therefore not possible to determine from the record whether the testable subset is comparable across arms or how the untested participants would affect an all-randomized-participant comparison.
An intention-to-treat analysis generally retains participants in their randomized groups, regardless of treatment received, and aims to preserve the benefits of randomization. Other analysis populations may be defined for different purposes, but their membership and rationale need to be clear. The registry record does not report the primary analysis population beyond the clinician-judged testable population, nor does it identify an intention-to-treat analysis or describe how deviations from assigned treatment were handled.
How should randomization and masking be read?
Randomization is a design method for allocating treatment by chance. In general, it reduces the risk that treatment choice is systematically linked to measured or unmeasured baseline factors, although chance imbalances can still occur. The registry labels allocation randomized but does not describe the sequence generation, concealment, or any stratification. Triple masking is also recorded, and the swallowing outcome description specifically says that a blinded observer judged the test. The registry does not specify which other trial roles were masked or whether masking was assessed.
These design features can strengthen the credibility of a comparison, but they do not themselves establish an outcome effect. The result still depends on complete outcome reporting, the appropriate analysis population, the statistical method, and uncertainty estimates. Because the primary result is not reported in the registry record, the influence of those elements cannot be evaluated for the primary question.
What do planning illustrations mean?
The record describes sample-size planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. Such illustrations answer a conditional planning question: how many participants per arm might be needed under the chosen assumptions to detect a target effect with a specified power. They are not observed trial outcomes and are not evidence that the trial had a particular probability of detecting its true effect. They are not the trial's original design justification, and the registry does not report the original sample-size rationale.
General statistical principle: planning based on an effect estimated in the same study can be sensitive to how uncertain or unstable that estimate is. A planning exercise should therefore be read as an assumption-dependent illustration, not as a substitute for the confidence interval around the trial result. The record's stated assumptions are available, but the underlying primary comparison result and the numerical outputs of the planning illustrations are not reported in the registry record described for this analysis.
What is not available for evaluating the analysis?
The registry record does not report the statistical test or model used for the primary endpoint, any covariate adjustment, an analysis plan, interim analyses, or a multiplicity strategy. It also does not report primary endpoint effect estimates, confidence intervals, or p-values. These absences limit assessment of the analysis choices and prevent an independent check of whether a particular reported estimate follows from the recorded counts. Statistical methods can clarify how an available estimate should be interpreted, but cannot supply outcome data that are not reported.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one primary swallowing outcome and several secondary outcomes, including time from anesthetic discontinuation to first response to command, nausea and vomiting, and time to first ability to swallow. Nausea and vomiting appears more than once in the outcome list. The registry record does not report a multiplicity plan, such as which comparisons were confirmatory, whether secondary outcomes were adjusted for multiple testing, or how outcome time points were prioritized. Without such details, a collection of separate tests would need to be interpreted with caution: in general, the chance of at least one apparently notable result can increase when many hypotheses are tested.
Handling of missing or unobserved primary assessments is also not reported. The primary outcome applies to participants judged able to take the test (n=57), but the record does not give arm-specific numbers assessed, reasons participants were not assessed, or an imputation or sensitivity-analysis approach. General statistical principle: missing outcome data can affect both the estimated treatment contrast and its uncertainty, particularly when the likelihood of assessment is related to treatment or recovery. The available record does not establish whether missingness was balanced or ignorable.
The analysis population is not described beyond the testable group. The registry does not state whether the main analysis followed randomized assignment for all participants, how treatment discontinuations or protocol deviations were handled, or whether additional populations were analyzed. The enrollment field records 107, while the primary outcome description identifies n=57 testable participants; the registry does not reconcile these populations. These omissions prevent a full assessment of the analysis set and the robustness of the primary comparison.
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 |
|---|---|---|---|
| Sevoflurane | 0 | 41 | 0.0% |
| Desflurane | 0 | 40 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Sevoflurane | 0 of 41 |
| Desflurane | 0 of 40 |
The serious adverse event entries list 0 participants affected among 41 at risk in the sevoflurane group and 0 among 40 at risk in the desflurane group. The registry also lists 0 participants with other adverse events among 41 and 40 at risk, respectively. These are the posted counts and denominators, not a complete description of all possible safety outcomes or their timing.
The record lists no serious adverse event terms. It does not report deaths, so the death information should not be read as a count of zero. Zero events in the listed entries do not prove that the underlying risk is absent. General statistical principle: when an event is uncommon, a study may observe no events even though uncertainty about the event rate remains. A comparative safety interpretation would also require consistent event definitions, observation periods, and a suitable analysis; those details are not reported in the registry record.
These safety entries should be read separately from the primary swallowing outcome. They do not establish whether either anesthetic is safer overall, and they do not answer the trial's primary question about recovery of swallowing.
12. What the Result Does, and Does Not, Mean
The registry record documents a randomized comparison of sevoflurane and desflurane in the context of rocuronium paralysis reversed with neostigmine and glycopyrrolate. It specifies a swallowing assessment at 2 minutes after response to command and describes the criteria used by the blinded observer. Those details define the intended clinical measurement and the treatment contrast.
However, the primary outcome result is not reported in the registry record. There are no arm-specific swallowing counts, denominators for the primary test, effect estimate, confidence interval, or p-value in the information available. Consequently, the posted record does not show whether the groups differed, how large any difference might have been, or how precise an estimate would be. It would be inappropriate to infer a treatment effect from the trial rationale, study title, design, or safety entries.
The primary endpoint population is limited to people judged able to take the test (n=57). The record does not explain the selection into that population or how participants without an assessment were handled. This matters because an observed result among testable participants may not answer exactly the same question as an analysis of every randomized participant. The registry also does not describe a multiplicity plan for the listed secondary outcomes or give the statistical method used for the primary comparison.
The safety entries report no serious adverse events or other adverse events in the listed group counts, while deaths are not reported in the registry record. Those data are limited to the recorded categories and denominators and cannot establish an overall safety profile. In short, the record makes the study question and measurement approach clear, but does not provide the primary results needed to decide what the comparison found. General statistical interpretation can explain what such results would mean, but it cannot replace unreported outcome data.
13. Why This Trial Matters Statistically
This trial addresses a statistical distinction between apparent wakefulness and a directly assessed protective function. The registry rationale notes that response to command may not coincide with recovery of airway reflexes. Measuring the ability to swallow therefore targets a functional outcome rather than treating wakefulness as a complete proxy for recovery. That distinction is useful when defining an endpoint: a trial should measure the construct relevant to its question as directly as practical.
The randomized, parallel-group comparison also offers a clear framework for separating the anesthetic contrast from the shared context of rocuronium and its reversal. General statistical principle: keeping other treatment components consistent across arms can make the target contrast easier to interpret, although actual delivery and adherence still matter. The registry does not report full treatment-delivery data or details of allocation procedures, so the extent to which the intended comparison was maintained cannot be assessed from this record alone.
The trial is also a reminder that endpoint availability and analysis population are central parts of interpretation. The swallowing outcome applies only to participants judged able to take the test, recorded as n=57, whereas overall enrollment is 107. Without an explanation of who could not be tested and how that information entered the analysis, readers cannot determine how representative the tested subset is of the randomized groups.
Most importantly, a well-defined question and endpoint do not substitute for posted results. The registry record includes no primary arm-specific counts or estimate, so statistical importance lies in distinguishing design information from evidence about the outcome. The recorded design explains what the investigators intended to compare; only complete results with denominators and uncertainty could establish the observed contrast and its precision.
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 from the registry record is that the primary endpoint results are not reported. Arm-specific counts, endpoint denominators, a treatment-effect estimate, and measures of uncertainty are absent, preventing assessment of the direction, magnitude, and precision of the primary comparison.
The primary outcome is restricted to participants considered able to take the test (n=57). The record does not explain the criteria used to determine testability, why other participants were not assessed, or whether reasons differed by arm. It also does not describe missing-data handling, the primary analysis population beyond this testable group, or sensitivity analyses. These omissions limit evaluation of selection and missing-outcome concerns.
Although allocation is recorded as randomized and masking as triple, details of sequence generation, allocation concealment, masked roles, and masking success are not reported in the registry record. The statistical analysis plan, model or test, covariate adjustment, interim analyses, and multiplicity handling are also not reported. The registry lists several secondary outcomes, but does not provide their results in the information summarized by the primary endpoint.
The registry records enrollment of 107, while the brief summary describes a plan to randomly assign 100 patients; it does not explain the difference. The listed serious and other adverse event counts have limited scope, and deaths are not reported. These limitations mean the record is useful for identifying the trial's design and intended measurement, but insufficient for a full assessment of efficacy or overall safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Impact of Anesthetic Choice (Sevoflurane Versus Desflurane) on Airway Reflex Recovery in the Context of Antagonized Neuromuscular Block — NCT01199237.
- Registry record last updated 2014-05-16; status last verified 2014-05.
- Results first posted 2014-05-08.
- 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.
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18. Record Summary
The registry identifies NCT01199237 as a completed Phase 4 randomized, triple-masked, parallel-group trial sponsored by University of California, San Francisco. It compares sevoflurane with desflurane in participants receiving rocuronium and neostigmine plus glycopyrrolate reversal. Recorded enrollment is 107; the primary endpoint population is limited to participants judged able to take the swallowing test (n=57).
The primary outcome is the number of participants able to swallow 20mL of water at 2 minutes after response to command, judged using the stated transit and airway-response criteria. The registry record does not report the primary arm-specific counts, effect estimate, confidence interval, or p-value. Serious and other adverse events are listed as 0 in each group's reported at-risk count; deaths are not reported in the registry record. Missing-data methods, multiplicity handling, and the primary statistical analysis plan are not reported.