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 The Effect of Neuromuscular Blockade on the Composite Variability Index (CVI) During Laryngoscopy (NCT01450813), a randomized na study. The primary outcome is The Mean Difference in CVI Between Pre-laryngoscopy and Post-laryngoscopy for Each of the Four Rocuronium Groups.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01450813 |
| Phase | NA |
| Condition | Anesthesia, Neuromuscular Blockade |
| Allocation | Randomized |
| Design model | Single Group |
| Masking | Double |
| Enrollment | 80 |
| Arms in the primary outcome | 4 |
| Lead sponsor | Medtronic - MITG |
| Results posted | Yes |
2. Clinical Question
Population
The record describes patients undergoing general anesthesia, with the primary outcome assessed around laryngoscopy. The population field for the primary outcome is not reported in the registry record. Enrollment was 80, while the posted primary outcome includes group sample sizes of 20.0, 19.0, 20.0, and 16.0. The record does not explain the difference between enrollment and the reported group counts.
Intervention
The study assigned participants to rocuronium doses of 0.2 mg/kg, 0.4 mg/kg, or 0.6 mg/kg. The stated purpose was to assess whether rocuronium dose affects the CVI measurement differently. The registry description anticipated diminished CVI values in the highest-dose group, but this expectation is not itself a result.
Comparator
The comparator was saline 0.06 ml/kg, described as the no-rocuronium group. The four assigned groups were saline and the three rocuronium doses. Although the record identifies randomization and double masking, details about how allocation and masking were implemented are not reported in the registry record.
Primary question
The primary outcome asks how much mean CVI changed between the three minutes before laryngoscopy and the three minutes after it, within each dose group. The registry records results at six minutes after the dose, with laryngoscopy at three minutes after the study intervention. The reported analysis also compares the four groups using ANOVA. It does not report individual pairwise comparisons or a dose-specific estimate relative to saline.
3. Trial Design
The registry describes a randomized, double-masked trial with enrollment of 80. It lists four study groups: saline 0.06 ml/kg, rocuronium 0.2 mg/kg, rocuronium 0.4 mg/kg, and rocuronium 0.6 mg/kg. The study record classifies the model as single group, even though it lists these four assigned groups. The meaning of that model classification in relation to the listed arms is not reported in the registry record.
The stated study question concerns whether rocuronium dose affects the CVI response around laryngoscopy. The primary endpoint is the mean change in CVI from the period before laryngoscopy to the period after it, reported separately by group. The timeframe specifies six minutes after the dose, with laryngoscopy three minutes after the study intervention. The record also lists a secondary outcome concerning average CVI during the maintenance phase of anesthesia for two remifentanil groups. Further details of that outcome and its relationship to the four listed rocuronium groups are not reported in the registry record.
The reported primary-outcome group sizes are 20.0 for saline, 19.0 for rocuronium 0.2 mg/kg, 20.0 for rocuronium 0.4 mg/kg, and 16.0 for rocuronium 0.6 mg/kg. The record does not explain why these outcome counts differ from the overall enrollment or whether any participants were excluded from particular analyses. The randomization method, masking procedures, allocation concealment, and analysis population are not reported in the registry record. Study start is recorded as 2009-06, primary completion as 2013-12, and status as completed.
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 | Group 1 | Group 2 | Group 3 | Group 4 |
|---|---|---|---|---|
| STARTED | 20 | 20 | 20 | 20 |
| COMPLETED | 19 | 19 | 20 | 17 |
| NOT COMPLETED | 1 | 1 | 0 | 3 |
Reasons for not completing this period:
| Reason | Group 1 | Group 2 | Group 3 | Group 4 |
|---|---|---|---|---|
| Physician Decision | 1 | 1 | 0 | 3 |
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 | Group 1 | Group 2 | Group 3 | Group 4 | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 19 | 19 | 20 | 17 | 75 | |
| Age, Continuous | years | 35.9 (SD 12.3) | 38.6 (SD 14.6) | 39.4 (SD 12.7) | 32.9 (SD 6.4) | 37.9 (SD 11.34) |
| Sex: Female, Male: Female | Participants | 9 | 8 | 8 | 9 | 34 |
| Sex: Female, Male: Male | Participants | 10 | 11 | 12 | 8 | 41 |
6. Primary Endpoint
The registry lists the primary outcome as The Mean Difference in CVI Between Pre-laryngoscopy and Post-laryngoscopy for Each of the Four Rocuronium Groups, measured over Six minutes after the dose of rocuronium with laryngoscopy at 3 minutes after the study intervention.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the mean change in Composite Variability Index (CVI) between three minutes before laryngoscopy and three minutes after laryngoscopy, reported for each of the four groups. The stated timeframe is six minutes after the rocuronium dose, with laryngoscopy at three minutes after the study intervention. CVI is described as a measure combining variability in processed electroencephalography signals: Bispectral Index (BIS), variability of electromyogram activity, and variability of BIS.
The registry describes the CVI scale as ranging from 0 to 100. In that description, lower CVI values represent a lower likelihood of intraoperative somatic responses, while higher values represent a higher likelihood. The endpoint is used to examine whether the measured CVI change around laryngoscopy differs across the assigned rocuronium doses. It is a monitor-derived measurement, not a direct report of a participant’s experience or a direct measure of clinical benefit. The posted endpoint is a group mean change; the registry record does not report individual participant trajectories or the distribution of changes within each group.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary outcome reports mean CVI changes of 2.4 for saline, 1.39 for rocuronium 0.2 mg/kg, 0.48 for rocuronium 0.4 mg/kg, and 0.17 for rocuronium 0.6 mg/kg. Their respective 95% confidence intervals are 2.15 to 2.64, 0.95 to 1.83, 0.24 to 0.72, and -0.04 to 0.38. The reported group sizes are 20.0, 19.0, 20.0, and 16.0, respectively.
Across these reported estimates, the mean change is smaller in the groups assigned higher rocuronium doses. This describes the pattern of the posted group means; it does not establish that dose caused the differences or identify which pairs of groups differ. The registry reports an ANOVA result of p < 0.05 for the four groups. That result is evidence of an overall difference under the reported analysis, but it does not identify the specific group contrasts responsible for the result. No pairwise estimates or corresponding confidence intervals are reported in the registry record.
The confidence intervals convey uncertainty around each group mean change. The interval for the 0.6 mg/kg group extends from -0.04 to 0.38, so its reported uncertainty includes values on either side of zero. That alone does not establish whether a within-group change is statistically distinguishable from zero, because the record does not specify a test of each group against zero. Nor does the omnibus ANOVA answer whether each dose differs from saline.
Interpretation is limited by information not reported in the registry record: the prespecified statistical plan, handling of missing outcome data, exact analysis population, and whether any adjustment was made for multiple comparisons. The group counts also vary. The posted estimates should therefore be read as descriptive group results alongside the reported overall ANOVA, rather than as a complete account of all dose-specific comparisons.
9. Statistical Methods Explained
What does a group mean represent?
The endpoint is a continuous measure, and the registry reports a mean change for each assigned group. A mean summarizes the group’s observed changes with one central value. It does not show how individual participants’ changes were distributed or whether a few observations strongly influenced the mean. The group sample sizes give context for the estimates, but the registry record does not provide a separate measure of spread for the primary outcome.
The displayed confidence intervals are 95% confidence intervals for the group mean changes. In general, a confidence interval gives a range of values compatible with the data and the assumptions of the interval procedure. It communicates uncertainty more directly than a point estimate alone. It is not a range containing a stated proportion of individual participant outcomes, and it does not show the probability that a particular value is true. The methods used to calculate these intervals are not reported in the registry record.
What does the ANOVA result test?
The registry reports an ANOVA across the four groups, with p < 0.05. In general, analysis of variance evaluates whether the observed group means are compatible with a common mean, under the model assumptions. An omnibus result does not say which particular groups differ. Establishing the differences between specific dose groups and saline would ordinarily require planned contrasts or pairwise comparisons, but those results are not reported in the registry record.
A p-value describes how compatible the observed data are with a specified null model, under the assumptions of the analysis. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of a difference. The posted threshold is p < 0.05; the registry does not give a more precise p-value or explain whether the analysis was intended as a superiority, equivalence, or non-inferiority assessment. Although the analysis classification refers to non-inferiority or equivalence, the associated hypothesis, margin, and interpretation are not reported in the registry record.
Why do the confidence intervals matter?
The confidence intervals describe precision for each group mean change, rather than the uncertainty in a difference between two groups. To assess a dose against saline, readers need an estimate of that contrast and its uncertainty, or a clearly specified comparison test. The record lists only the group-specific means and intervals. The intervals should not be used as a substitute for the missing contrast estimates: overlap or non-overlap between separate group intervals is not itself the reported test of a between-group difference.
In general, precision depends on the amount of information and variability in the data, along with the calculation method. The group sizes differ, and the posted primary results do not give the outcome’s within-group standard deviations or another spread measure. The interval widths therefore cannot be translated into a complete account of variability from the record alone.
What can and cannot be recalculated?
The posted results do not include a two-arm continuous-outcome comparison with the information needed for a simple unadjusted recalculation. The registry identifies that such comparisons are unavailable or not estimable. Consequently, no recalculated pairwise estimates, p-values, or planning illustrations for a specified two-arm contrast can be described from this record. This is distinct from the sponsor-reported four-group ANOVA, which is reported as p < 0.05.
In general, a recalculation from summary statistics is not the same as the trial’s full analysis. It may not account for covariate adjustment, repeated measurements, clustering, or other features of the original design. Those features and the statistical analysis plan are not reported in the registry record. The record also does not provide the inputs needed to judge whether the reported ANOVA accounted for the study’s allocation structure or any repeated observations.
Why does over-dispersion matter?
General statistical context: when outcome variability is greater than a model assumes, standard errors can be too small and confidence intervals too narrow, making results appear more precise than warranted. Conversely, a model that does not reflect the data can misstate uncertainty in other ways. Over-dispersion is particularly discussed for count outcomes, whereas this primary endpoint is continuous. The registry does not report a diagnostic assessment of model assumptions or details sufficient to evaluate the ANOVA fit. There is no basis in the record to assert that over-dispersion occurred in this analysis.
For a continuous endpoint, relevant considerations generally include the distribution of residuals, the relation between variability and group, independence of observations, and the suitability of the mean-based comparison. These are general considerations, not reported findings about this trial. The registry record does not state which checks were performed or whether an alternative analysis was used.
How should sample-size illustrations be understood?
General statistical context: planning calculations use assumptions about an effect, variability, significance level, allocation, and analysis method to illustrate how much information a future study might need. Such calculations are prospective planning aids, not evidence about the probability that the completed trial detected an effect. The record does not provide numerical planning illustrations for a two-arm comparison of this continuous endpoint, and the comparison is identified as unavailable or not estimable. No sample-size estimate or observed-power claim can therefore be drawn from the posted primary results.
The study enrolled 80 participants, but enrollment alone does not establish the precision or adequacy of the primary analysis. The outcome group sizes and confidence intervals are more directly relevant to the displayed estimates, while the missing design rationale prevents assessment of how the planned enrollment related to the intended analysis.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| ANOVA | not reported | < 0.050 |
The sponsor-reported result is an ANOVA across the four listed groups, with p < 0.05. This is the reported inferential analysis for the primary outcome. The registry also contains group-specific mean changes and 95% confidence intervals, but it does not report a two-arm contrast estimate or the ingredients needed for an unadjusted recalculation of such a comparison. The registry identifies the continuous endpoint comparison as unavailable or not estimable for that purpose.
Accordingly, there is no recalculated pairwise result to set against the sponsor’s ANOVA. The ANOVA addresses the overall pattern across groups, while a pairwise recalculation would address a different question, such as a particular dose compared with saline. The registry record does not report those dose-specific tests. It also does not describe the ANOVA’s full specification, any planned contrasts, or the rationale for labeling the analysis as non-inferiority or equivalence. The sponsor’s reported analysis therefore remains the available inferential result; the registry’s posted group means and intervals can be read descriptively, but they do not replace or reproduce that analysis.
11. Multiplicity, Missing Data and Analysis Populations
The registry reports an overall ANOVA across four groups and lists one secondary outcome. It does not state whether additional endpoints, time points, subgroup analyses, or contrasts were tested, nor does it describe a strategy for controlling the risk of false-positive findings when multiple hypotheses are considered. No multiplicity adjustment is reported in the registry record. Because the omnibus test does not identify specific group differences, the lack of reported pairwise results also means there is no stated family of dose-versus-saline comparisons to assess for adjustment.
The primary outcome group sizes are 20.0, 19.0, 20.0, and 16.0, while total enrollment is 80. Reasons for the differing outcome counts, participant flow, and treatment of missing endpoint measurements are not reported in the registry record. It is therefore not possible to determine from the record whether the outcome analysis included all randomized participants, only participants with observed measurements, or another defined analysis population. The analysis population and any imputation or sensitivity analyses are not reported.
General statistical context: missing outcome data can affect both the precision and the interpretation of an estimate, especially when the likelihood of missingness is related to treatment or outcome. The implications depend on why data are missing and how the analysis handles them; neither can be inferred from the group counts alone. The registry also does not report whether participants were analyzed according to randomized assignment or whether any exclusions occurred after randomization.
The record’s classification of the reported analysis as non-inferiority or equivalence does not supply the required decision framework. The margin, hypotheses, and analysis plan are not reported in the registry record. It is consequently not possible to determine how that classification relates to the posted ANOVA or whether a prespecified multiplicity approach was used.
12. 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 |
|---|---|---|---|
| Group 1 | 0 | 19 | 0.0% |
| Group 2 | 0 | 19 | 0.0% |
| Group 3 | 0 | 20 | 0.0% |
| Group 4 | 0 | 17 | 0.0% |
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 |
|---|---|
| Group 1 | 0 of 19 |
| Group 2 | 0 of 19 |
| Group 3 | 0 of 20 |
| Group 4 | 0 of 17 |
The registry reports zero serious adverse events and zero other adverse events in each of the four groups. The numbers listed at risk for serious and other adverse events are 19 for saline, 19 for rocuronium 0.2 mg/kg, 20 for rocuronium 0.4 mg/kg, and 17 for rocuronium 0.6 mg/kg. These safety denominators do not exactly match the primary endpoint group counts in every group. The record does not explain the differences.
These entries describe the adverse-event counts recorded in the registry; they do not establish that no events occurred outside the recorded categories or observation period. The registry does not provide event details, definitions, severity grades, follow-up duration, or an explanation of how participants at risk were determined. Death counts are not reported in the registry record. The absence of a recorded event in these entries should therefore be read as a feature of the posted safety data, not as a guarantee of no risk. Safety comparisons between groups are not reported as statistical tests, and the record does not provide estimates of comparative risk.
13. What the Result Does, and Does Not, Mean
The posted results describe mean CVI changes around laryngoscopy in four groups assigned saline or different rocuronium doses. The group means decrease across the listed dose groups, and the registry reports an overall ANOVA result of p < 0.05. The confidence intervals show the uncertainty attached to each group mean. Together, these results characterize the observed endpoint pattern in this study.
They do not establish which individual dose groups differ from saline, because dose-specific contrasts are not reported. The omnibus ANOVA is not a set of pairwise comparisons. The record also does not provide enough information to assess whether the result was adjusted for multiple testing, how missing measurements were handled, or which participants were included in the analysis. These gaps limit the strength of conclusions that can be drawn from the posted summary.
The endpoint is CVI, a processed monitor measure described as reflecting variability in EEG-derived signals. A change in that measure is not by itself proof of a change in a participant’s clinical state or experience. The registry description links higher and lower CVI values to the likelihood of intraoperative somatic responses, but the posted primary endpoint remains a group mean change in a monitor-derived scale. It should not be translated into a claim about patient benefit or harm.
The study’s stated aim was to examine how rocuronium dose relates to CVI response around laryngoscopy. The results provide an overall statistical signal and group-level estimates, but they do not fully resolve the specific dose comparisons or the practical meaning of the measured changes. The record does not report a clinical threshold for an important CVI difference or a sample-size justification that would clarify the intended precision.
14. Why This Trial Matters Statistically
This trial is statistically informative because it uses a continuous monitoring measure and reports both group means and confidence intervals across several assigned dose groups. Readers can see the observed pattern and the uncertainty around each group estimate, rather than relying only on a p-value. The reported ANOVA provides an overall comparison across the groups, but it also illustrates why an omnibus result and dose-specific questions are not interchangeable.
The registry record highlights the value of reporting the complete analysis plan and contrasts. A statistically significant overall result does not show which groups account for the pattern, how large a specific dose-versus-saline difference is, or how precisely that contrast is estimated. Group-specific means and intervals are useful descriptive information, but they do not answer those questions on their own.
The outcome also raises a general measurement issue: a monitor-derived score is not automatically a direct clinical outcome. Statistical interpretation needs to stay tied to what the measure represents and what the study actually assessed. In this case, the primary endpoint is the mean change in CVI around laryngoscopy, not a reported patient-centered endpoint.
Finally, the differing group counts, absent detail on missing data, and lack of a reported multiplicity strategy illustrate how registry summaries can leave important uncertainty about analysis populations and inferential scope. These are not reasons to disregard the posted results; they define the boundaries of what the record supports. Clear reporting of planned comparisons, analysis populations, and uncertainty would make the findings easier to evaluate and reproduce.
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 does not report the statistical analysis plan, the method used to calculate the confidence intervals, the ANOVA specification, or diagnostic checks for model assumptions. It also does not report planned dose-specific contrasts, the equivalence or non-inferiority margin associated with the analysis classification, or a multiplicity strategy. These omissions prevent a detailed assessment of how the reported analysis answers the stated dose question.
Primary outcome counts differ by group, and the record does not explain why they differ from one another or from the enrollment of 80. The analysis population, participant flow, reasons for missing measurements, and missing-data methods are not reported in the registry record. The posted results therefore do not establish whether the analysis followed randomized assignment or included all participants with available endpoint data.
The registry lists the model as single group while also identifying four intervention groups and reporting an ANOVA across those groups. Further explanation of that classification is not reported. Randomization and double masking are recorded, but the implementation details are absent. The record does not provide information on allocation concealment, adherence to assigned intervention, or other protocol deviations.
Only group means and 95% confidence intervals are posted for the primary endpoint; within-group spread measures and individual-level data are not reported. No pairwise estimates are reported, and the registry indicates that a simple two-arm continuous-outcome comparison is unavailable or not estimable. The reported ANOVA p-value is bounded as p < 0.05 rather than stated more precisely. The registry also does not report a clinical threshold for interpreting the magnitude of a CVI change. These limitations constrain assessment of precision, clinical meaning, and reproducibility.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: The Effect of Neuromuscular Blockade on the Composite Variability Index (CVI) During Laryngoscopy — NCT01450813.
- Registry record last updated 2017-05-12; status last verified 2017-04.
- Results first posted 2017-05-12.
- 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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19. Record Summary
The registry record describes a completed randomized, double-masked study with enrollment of 80. Participants were assigned to saline 0.06 ml/kg or rocuronium at 0.2 mg/kg, 0.4 mg/kg, or 0.6 mg/kg. The primary outcome was mean change in CVI between three minutes before and three minutes after laryngoscopy, at the stated timeframe of six minutes after the dose.
Posted group mean changes were 2.4, 1.39, 0.48, and 0.17, respectively, with 95% confidence intervals of 2.15 to 2.64, 0.95 to 1.83, 0.24 to 0.72, and -0.04 to 0.38. The registry reports an overall ANOVA result of p < 0.05. Pairwise dose comparisons, analysis-population details, and missing-data methods are not reported in the registry record. Adverse-event entries list zero serious and zero other adverse events in each group; further safety-analysis details are not reported.