Evaluation of Volatile Induction and Maintenance Anesthesia (VIMA) With Sevorane in Adult Patients Required General Anesthesia for Surgery in Terms of Quality of Anesthesia and Its Influence on Cardiovascular System in Common Clinical Practice: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of Volatile Induction and Maintenance Anesthesia (VIMA) With Sevorane in Adult Patients Required General Anesthesia for Surgery in Terms of Quality of Anesthesia and Its Influence on Cardiovascular System in Common Clinical Practice (NCT01282203), a registered phase not stated study. The primary outcome is Time to Loss of Consciousness of Patients Administered Anesthesia.

2. Clinical Question

The study’s broader objective was to collect information about general anesthesia in routine surgical practice and use those data to inform local recommendations. Its stated focus included the quality of anesthesia and its influence on the cardiovascular system during common clinical practice in Kazakhstan. The primary outcome captures one specific part of anesthesia induction: the time from administration of the anesthetic to the recorded loss of consciousness.

This question is descriptive in this study. The record describes a prospective, multicentre, non-interventional observational study, not a trial that assigned participants to different anesthetics or compared treatment groups under randomized conditions. Accordingly, the primary outcome can characterize observed induction times only if numerical results and the number of participants with outcome data are available. Neither the mean time nor its standard deviation is reported in the registry record. The record therefore identifies what was measured, but does not provide a numerical answer to the primary question.

3. Trial Design

NCT01282203 is a completed post-marketing observational study sponsored by AbbVie (prior sponsor, Abbott). The record gives a start date of 2011-07 and a primary completion date of 2011-11. Enrollment is listed as 1122. The study concerned general anesthesia for surgery in adults in Kazakhstan and was described as prospective and multicentre.

The study was non-interventional: Sevorane was prescribed for induction and maintenance of anesthesia in the usual manner, rather than assigned by the study under a randomized protocol. The listed group is “Adults Requiring Anesthesia for Surgery.” The registry record does not describe a separate control group or a stated allocation procedure. The listed group therefore should not be read as one side of a controlled treatment comparison.

The primary outcome was time to loss of consciousness, measured in minutes from administration of the anesthetic until loss of the eyelash reflex, within a timeframe of up to 10 minutes. The planned summary measure was the mean with standard deviation. The outcome population was all participants with available data. The registry record does not give the number with available primary-outcome data or the resulting mean and standard deviation.

Secondary outcomes listed in the record include systolic and diastolic blood pressure, mean arterial pressure, heart rate, electrocardiogram deviations during anesthesia, cardiac troponin and creatine kinase myocardial isoenzyme when available, and a correlation between anesthesiologists’ clinical experience and hemodynamic parameters. The record lists 15 outcome measures, but it does not report numerical results for these secondary measures in the information available for this analysis. It lists 0 analyses. Further protocol details, including a statistical analysis plan and sample-size justification, are not reported in the registry record.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All participants with available data were included in the analysis.

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 Time to Loss of Consciousness of Patients Administered Anesthesia, measured over Up to 10 minutes.

The primary endpoint is the time to loss of consciousness after the anesthetic was administered. It is measured in minutes, with loss of consciousness operationally defined as loss of the eyelash reflex. The stated assessment timeframe is up to 10 minutes, and the planned summary is a mean and standard deviation among participants with available data.

This endpoint describes the timing of an observable event during induction. A mean gives the average time across the participants included in the calculation. The standard deviation describes how spread out individual times are around that mean. Together, these summaries can convey both a typical observed time and the variability in timing, although neither can be interpreted without the actual numerical values and the number of participants contributing data.

In general, an endpoint needs a clear definition so that the measured event and its timing are understood consistently. The eyelash-reflex definition makes the recorded event more specific than an unqualified judgment of when consciousness was lost. However, the registry record does not describe measurement procedures, assessor training, or how differences in observation were handled. Those details are not reported in the registry record.

The numerical mean and standard deviation for this endpoint are not reported in the registry record. As a result, the endpoint definition is available, but the observed induction time and its precision cannot be characterized from the registry result information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The methods information in the registry record is limited. It identifies a prospective, multicentre, non-interventional observational study and states that the primary outcome was summarized as a mean with standard deviation. It does not report a detailed statistical analysis plan, an inferential model, a confidence interval, or a numerical primary result. The explanations below describe general statistical concepts rather than analyses documented for this study.

What does a mean describe?

General: A mean is the arithmetic average of the observations included in an analysis. For this outcome, each observation would be a time from anesthetic administration to loss of the eyelash reflex. A mean can summarize the central level of the observed times, but it does not show whether most observations are close to that value or whether the average is influenced by a small number of unusually short or long times. Interpreting a mean therefore benefits from a measure of spread and information about the distribution of the observations.

The registry record names standard deviation as the measure of spread. General: Standard deviation describes how dispersed observations are around their mean, in the same units as the original measurement. A relatively wider spread indicates more variation among observed times; a narrower spread indicates that the observations are more concentrated around the mean. The record gives neither the primary mean nor the standard deviation, so these descriptions cannot be applied to the study’s actual outcome values.

What would a confidence interval add?

General: A confidence interval expresses the statistical uncertainty around an estimated quantity under the assumptions of the method used to construct it. It is distinct from the standard deviation, which describes variation among individual observations. A confidence interval can help readers judge how precisely a population value is estimated, but its interpretation depends on the study design, analysis, and assumptions. No confidence interval for the primary outcome is reported in the registry record. There is therefore no registry-based interval with which to assess precision.

Why does the design matter?

General: In an observational study, treatment or care is not assigned by randomization for the purpose of creating comparable groups. The observed outcome can reflect the treatment as used in practice alongside patient characteristics, clinical decisions, and other features of the care setting. A descriptive average can summarize the recorded cohort, but an average alone cannot separate the contribution of each of these factors.

Here, the registry describes Sevorane use in the usual manner and does not state an allocation method or describe a like-for-like control group. A treatment contrast based on randomized groups is not available in the record. Even if a numerical cohort average were reported, it would remain a description of the observed setting rather than a randomized estimate of a treatment effect.

What does available-data analysis imply?

The registry states that all participants with available data were included in the primary outcome analysis. General: An available-data analysis uses observations for which the outcome was recorded; it does not, on its own, explain why other observations are absent or whether missingness could affect the result. If participants without an outcome differ in relevant ways from those with an outcome, a summary based only on available observations may not represent the full enrolled group. Assessing that possibility requires information about missingness and the analysis approach.

The number of participants with available primary-outcome data, the number missing, and any imputation or sensitivity methods are not reported in the registry record. Those omissions prevent assessment of how complete the endpoint data were and how missing values were handled.

What can planning calculations tell readers?

General: Sample-size calculations for a hypothetical comparison describe how many participants might be needed under specified assumptions about an effect, variability, allocation, and statistical error. Such calculations are planning illustrations, not observed outcomes and not proof that a study had a particular probability of detecting an effect. The assumptions stated for planning illustrations associated with this record include a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a fraction of an observed effect. The registry record does not describe this observational study as having two randomized arms or report a trial-specific sample-size justification. The planning assumptions should therefore not be confused with the design of the enrolled cohort.

The registry record lists 0 analyses. It does not identify a model for the primary endpoint, an adjustment strategy, or a method for handling multiple outcomes. These methods are not reported in the registry record, so no unreported analytical choices should be inferred.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Adults Requiring Anesthesia for Surgery")
n   <- c(945)
m   <- c(2.7)
sp  <- c(1.4)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Adults Requiring Anesthesia for Surgery  945  2.700  1.400  2.611  2.789

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 15 outcome measures, including the primary time-to-loss-of-consciousness endpoint and cardiovascular, electrocardiogram, biomarker, and experience-correlation measures. It lists 0 analyses. The number of outcomes alone does not reveal which outcomes were analyzed, how they were prioritized in practice, or whether statistical testing was performed. A multiplicity plan, including any adjustment for examining several outcomes, is not reported in the registry record.

General: When several outcomes or statistical tests are considered, the chance of finding at least one apparently notable result by chance can increase if the analyses are treated independently without an appropriate interpretive plan. Methods for addressing multiplicity depend on the purpose of the analyses and the relationships among outcomes. No correction method or testing hierarchy is reported for this study, so neither should be assumed.

For the primary endpoint, the record says that all participants with available data were included. This identifies the stated analysis population but does not quantify completeness. The number of participants with primary endpoint data, the number without data, and reasons for missing measurements are not reported in the registry record. The record also does not describe imputation, sensitivity analyses, or a comparison of participants with and without available data.

Cardiac troponin and creatine kinase myocardial isoenzyme are specified only if available. The registry record therefore does not establish that those measurements were obtained for all participants. Their completeness and any approach to missing biomarker data are not reported in the registry record. Without these details, the potential effect of incomplete measurements on summaries cannot be evaluated.

No statistical analysis plan, prespecified multiplicity procedure, or detailed analysis-population definition beyond the primary outcome’s available-data statement is reported in the registry record. These gaps limit the assessment of outcome selection, missing-data handling, and the inferential meaning of any results.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: ventricular fibrillation (0.2%), cardiac failure acute (0.1%), myocardial infarction (0.1%), atrial fibrillation (0.1%), cardiac arrest (0.1%).

For the listed group of adults requiring anesthesia for surgery, the registry record reports 1122 participants at risk for serious events and 4 participants affected. It also reports 1122 at risk for other events and 1 affected. These are descriptive counts in the record; no randomized comparator is described. The death result is not reported in the registry record.

The listed serious-event terms and percentages are ventricular fibrillation, 0.2%; cardiac failure acute, 0.1%; myocardial infarction, 0.1%; atrial fibrillation, 0.1%; cardiac arrest, 0.1%; and hypertension, 0.1%. The registry record does not give further event-level details such as timing, duration, outcome, or the number of occurrences for each term. It also does not state whether event terms could overlap within participants. The listed terms should therefore be read as registry summaries, not as mutually exclusive categories or a complete description of each participant’s clinical course.

These figures describe events recorded in this observational cohort. Without a like-for-like comparator, they do not quantify a difference between treatments. They also do not by themselves establish how much of an event was attributable to anesthesia, surgery, underlying health, or another factor. The registry record does not report additional information needed to make those distinctions.

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

The record documents a completed observational study of routine use of Sevorane for general anesthesia in adults undergoing surgery in Kazakhstan. It specifies a primary measure—time from anesthetic administration to loss of the eyelash reflex—and identifies a mean and standard deviation as the planned summary. It also lists cardiovascular and other secondary measures and reports descriptive safety counts.

The primary numerical result is not reported in the registry record. Without the mean, standard deviation, and number of participants contributing data, readers cannot determine the observed average induction time, the variability among participants, or the precision of an estimate. The outcome definition and timeframe explain what was intended to be measured, but they do not supply a result.

The study design also limits interpretation. This was a non-interventional study of usual clinical practice, and the record does not describe a randomized comparator. Consequently, an observed outcome in the cohort would not, by itself, establish what would have happened to the same population under a different anesthetic or care strategy. The record does not support a controlled causal comparison.

The reported serious-event and other-event counts are descriptive. They do not provide a comparative risk estimate, and the record does not report deaths. The listed serious-event terms and percentages do not include enough detail to reconstruct participant-level event histories or determine the cause of an event.

These limitations do not erase the descriptive purpose of a post-marketing observational study. Such a design can document measurements and events as care is delivered in practice. However, the registry record available for interpretation does not report the primary outcome result or numerical results for the listed secondary measures. It therefore supports an understanding of what the study set out to observe and how it was broadly organized, but not a numerical conclusion about its primary endpoint or a comparative conclusion about treatment effects.

14. Why This Trial Matters Statistically

This study is statistically notable because its design and its outcome definition need to be kept distinct. The primary endpoint is clearly described as a time measured from anesthetic administration to loss of the eyelash reflex, with a mean and standard deviation planned. That definition makes the target of measurement understandable. Yet the registry record does not report the corresponding numerical summary, so clarity of measurement cannot substitute for a result.

The study also illustrates the role of observational evidence in routine practice. A prospective, multicentre design can collect data in the setting where care is delivered, while non-interventional treatment use means that the data do not arise from randomized assignment. Statistical interpretation must reflect that distinction: descriptions of a cohort are not equivalent to estimates from a controlled treatment comparison.

The record’s outcome list spans induction timing, hemodynamic measures, electrocardiogram deviations, biomarkers when available, and a correlation involving anesthesiologists’ clinical experience. That breadth makes completeness and analysis plans particularly relevant. The record lists 15 outcome measures and 0 analyses, but does not report how multiplicity was handled, how missing measurements were addressed, or which secondary results were obtained. These are not minor details when readers are deciding how much weight to give a collection of outcomes.

The registry record also demonstrates why enrollment should not be confused with outcome completeness. Although enrollment is 1122, the primary analysis population is stated to include participants with available data, and the number with endpoint measurements is not reported. The enrolled total alone cannot establish the denominator for the primary outcome.

For these reasons, the statistical value of this record lies partly in what it makes explicit—the design, endpoint definition, and stated analysis population—and partly in the limits of what it reports. Careful reading distinguishes cohort description from causal comparison, enrollment from analyzed observations, and an endpoint definition from an endpoint result.

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 primary limitation for interpretation is the absence of a numerical result for the main endpoint. The registry record identifies time to loss of consciousness as the primary outcome and specifies a mean and standard deviation, but reports neither value. It also does not state how many participants contributed endpoint data. This prevents direct assessment of the observed time, its variability, and its precision.

The registry record describes the study as observational and non-interventional, with Sevorane prescribed in usual practice. It does not describe randomized assignment or a separate control group. The record therefore does not provide a like-for-like comparator for attributing observed outcomes to the anesthetic. The stated allocation method is not reported in the registry record.

Although the primary outcome population is defined as participants with available data, missingness is not quantified. Reasons for missing primary measurements, missing-data methods, and sensitivity analyses are not reported. The biomarkers are identified as collected if available, but their actual completeness is not stated. These omissions leave uncertainty about how representative the available measurements are.

The record lists 15 outcome measures but does not report a multiplicity strategy or detailed analysis plan. It lists 0 analyses. Thus, the intended treatment of multiple outcomes, the statistical methods used for secondary outcomes, and any adjustment for participant or clinical factors are not reported in the registry record.

Safety information is also limited to the listed counts and serious-event terms and percentages. Death results are not reported in the registry record, and event timing, outcomes, participant-level overlap, and attribution are not described. The record does not provide enough information to make comparative safety estimates or determine the causes of the listed events.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Evaluation of Volatile Induction and Maintenance Anesthesia (VIMA) With Sevorane in Adult Patients Required General Anesthesia for Surgery in Terms of Quality of Anesthesia and Its Influence on Cardiovascular System in Common Clinical Practice — NCT01282203.
• Registry record last updated 2013-03-04; status last verified 2013-01.
• Results first posted 2013-01-07.
• 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

NCT01282203 is a completed, prospective, multicentre, non-interventional post-marketing observational study sponsored by AbbVie (prior sponsor, Abbott). The record gives a start date of 2011-07, a primary completion date of 2011-11, and enrollment of 1122 adults requiring general anesthesia for surgery in Kazakhstan.

The primary endpoint was time to loss of consciousness, defined by loss of the eyelash reflex and measured from anesthetic administration, within a timeframe of up to 10 minutes. The planned summary was a mean and standard deviation among participants with available data. The numerical primary result and the number contributing data are not reported in the registry record.

The record lists cardiovascular, electrocardiogram, biomarker, and clinical-experience outcomes, 15 outcome measures, and 0 analyses. It reports 4 participants with serious events and 1 with other events among 1122 at risk in the listed group. Death results are not reported in the registry record.