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 Comparison of Two Electroencephalograms (EEG) Monitors in Patients Undergoing General Anesthesia (NCT02928172), a na na study. The primary outcome is Movements as Response to Laryngeal Mask Airway (LMA) Insertion.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02928172 |
| Phase | NA |
| Condition | Anesthesia, Deep Sedation |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 60 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Cedars-Sinai Medical Center |
| Results posted | Yes |
2. Clinical Question
Population
The registry describes patients undergoing surgery under sedation and general anesthesia. It focuses on responses during airway management, particularly Laryngeal Mask Airway (LMA) insertion during induction. Eligibility criteria and further participant characteristics are not reported in the registry record.
Intervention
Participants were to have both the qCON-qNOX monitor and the BIS monitor. The stated objectives include comparing qCON, an index of hypnosis, with BIS, and assessing qNOX as an index related to pain or nociception and as a possible indicator of response to nociceptive stimulation.
Comparator
There is no separate control group or assigned monitor group described. The study is listed as single-group and observational, with both monitors used in the same group. Thus, the registry does not describe a randomized, between-group comparison of the devices.
Primary question
The primary outcome is the total number of movements reported for the group during LMA insertion. The stated hypothesis concerns whether qNOX is statistically correlated with rough clinical signs of insufficient anti-nociception, including movement. The registry record does not report the movement total or a correlation estimate, so it does not establish how the recorded outcome relates to qNOX.
3. Trial Design
This is a completed observational study registered as NCT02928172. The record lists an enrollment of 60, a single-group model, and no allocation. It describes a group called “Depth of Anesthesia” in which subjects would have both the qCON-qNOX and BIS monitors. Masking is listed as none. The study is not described as a randomized comparison, and the registry record does not specify a separate group receiving only one of the monitors or a control condition.
The study’s stated focus is monitoring responses to nociceptive stimuli during general anesthesia using electroencephalographic signals. Its objectives include comparing the qCON and BIS hypnosis indexes, assessing qNOX alongside qCON, and assessing qNOX as an indicator of response to nociceptive stimulation. The hypothesis specifically connects qNOX with clinical signs such as movement during LMA insertion, skin incision, and LMA removal. The primary outcome named in the record, however, is the number of movements in response to LMA insertion.
The record gives a start date of 2018-01-02 and a primary completion date of 2023-02-20, and lists the study as completed. The phase is recorded as NA. Further details about recruitment, monitoring procedures, timing of device readings, or the protocol’s planned statistical analysis are not reported in the registry record. The observational, single-group structure is important when interpreting the comparison language in the study title: the record describes monitoring with both devices in one group, not a randomized comparison of separate device groups.
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 | Depth of Anesthesia |
|---|---|
| STARTED | 60 |
| COMPLETED | 59 |
| NOT COMPLETED | 1 |
Reasons for not completing this period:
| Reason | Depth of Anesthesia |
|---|---|
| Device did not record data | 1 |
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 | Depth of Anesthesia |
|---|---|---|
| Participants analysed | 59 | |
| Age, Continuous | years | 52.2 (SD 15.9) |
| Sex: Female, Male: Female | Participants | 45 |
| Sex: Female, Male: Male | Participants | 14 |
| Race/Ethnicity, Customized: Asian | Participants | 5 |
| Race/Ethnicity, Customized: Black or African American | Participants | 7 |
| Race/Ethnicity, Customized: White | Participants | 43 |
| Race/Ethnicity, Customized: Hispanic or Latino | Participants | 4 |
| Region of Enrollment: United States | Participants | 59 |
6. Primary Endpoint
The registry lists the primary outcome as Movements as Response to Laryngeal Mask Airway (LMA) Insertion, measured over Approximately 10 minutes.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Number of Movements for the whole group |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled “Movements as Response to Laryngeal Mask Airway (LMA) Insertion.” It measures the total number of movements for the group as a whole, rather than a movement count for each participant. The listed timeframe is approximately 10 minutes. The description notes that LMA insertion occurs during induction, lasting an average of 5-10 minutes.
Movement is used as a rough clinical sign of insufficient anti-nociception in the study’s stated hypothesis. In that context, the endpoint is intended to capture a behavioral response around a specific nociceptive stimulus, while the study assesses whether qNOX readings are related to such responses. The registry’s primary outcome description calls for a group-level count; it does not report an individual-level movement measure, a threshold for what counts as movement, or a statistical measure linking qNOX to movement.
Those distinctions matter for interpretation. A group total describes the number of recorded movements across the group, but on its own does not show how many participants moved, how movements were distributed among participants, or whether movement coincided with a particular qNOX value. The actual total and any analysis connecting the count to monitor readings are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clinically observable response—movement during LMA insertion—as the primary outcome, and describes qNOX as an index to be assessed in relation to nociceptive stimulation. But it does not post a primary endpoint result. The total number of movements, a correlation estimate, and an uncertainty measure for any relationship are not reported in the registry record. Consequently, the registered information does not quantify the frequency of movement or show how closely qNOX tracked movement.
The study’s stated objectives also include comparing qCON with BIS for monitoring hypnosis. Both devices are described as being used in the single group. No results for either index, no device-to-device agreement estimate, and no comparative analysis are reported in the registry record. The title’s use of “comparison” should therefore not be read as evidence of a randomized or between-group design: allocation is listed as NA, and the record specifies a single-group model with both monitors.
The enrollment is listed as 60. The adverse-event record lists 59 participants at risk in the study group, but the reason for that figure and its relationship to enrollment are not reported in the registry record. These are different registry counts, and the available information does not explain the difference. The completed status indicates that the study is registered as completed; it does not supply the missing outcome estimates or analysis details.
The registry lists 3 outcome measures and identifies “Number of Intraoperative Movements” as a secondary outcome, as well as the primary LMA-insertion movement outcome. The record does not post outcome results or analyses. In statistical terms, therefore, there is no posted estimate to interpret for the primary endpoint and no reported precision with which to judge that estimate. A confidence interval, when reported, describes the range of values compatible with the data and analysis under its assumptions; no such interval for this endpoint is reported in the registry record.
The sample-size figures described as planning illustrations are not study findings and are not evidence of observed power. The stated illustration assumptions include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the detectable effect expressed as a fraction of the observed effect. The record describes the illustration as separate from the trial’s own design. Those assumptions do not turn this single-group observational study into an equal-arm trial, and no trial-specific sample-size justification is reported in the registry record.
Overall, the registered information establishes the study’s intended monitoring questions, its single-group design, and the type of primary outcome. It does not establish the observed movement count, the association of qNOX with movement, or a comparative performance result for qCON and BIS. Any conclusion about the size, direction, or precision of those relationships would require results and analysis information not reported in the registry record.
9. Statistical Methods Explained
Statistical interpretation depends on the design and on how the outcome was defined. This study is listed as observational, with a single group and no allocation. Both qCON-qNOX and BIS are to be used in that group. Thus, the registry describes monitoring in the same participants rather than assignment to distinct monitor groups. General statistical principle: a comparison of readings from devices used in the same group is different from a randomized comparison of outcomes between separately assigned groups; the analysis needs to account for how measurements are paired or otherwise related. The analysis approach for the monitor comparison is not reported in the registry record.
What does a group-level count tell the reader?
The primary endpoint is the total number of movements for the group during the stated timeframe around LMA insertion. A count is a nonnegative outcome: it records how many events occurred. Here, the registry explicitly says the total is for the group as a whole, not per participant. General statistical principle: an aggregate count does not reveal the distribution of events among participants. A total might arise from many participants with few movements or from a smaller number with more movements; without participant-level counts, those patterns cannot be distinguished. The posted record does not give a movement total, participant-level count data, or a description of how movement was classified.
Count outcomes are often analyzed with methods designed for counts rather than methods that assume a continuous, normally distributed outcome. General statistical principle: count data can vary more than a simple model expects, a feature called over-dispersion. If over-dispersion is present and ignored, standard errors and confidence intervals can be too small, making results look more precise than the data justify. Whether over-dispersion was assessed or what model was used is not reported in the registry record. The group-level presentation of the primary endpoint also limits what can be inferred about individual variation.
How should a proposed correlation be understood?
The study hypothesis proposes a relationship between qNOX and clinical signs of insufficient anti-nociception, including movements. General statistical principle: correlation describes the degree to which two measured quantities vary together. It does not by itself establish that one quantity causes the other. Interpreting a correlation also requires knowing what observations were paired, how repeated readings were handled, and what estimate and uncertainty were obtained. The registry record does not report a correlation coefficient, its confidence interval, the number of paired observations, or the analysis method. The primary outcome’s group-level total is not, by itself, enough to calculate or interpret a participant-level correlation.
The objectives also refer to qCON and BIS as indexes of hypnosis. General statistical principle: comparing two measurement devices may involve examining their association, agreement, or relative ability to distinguish a response. These are different questions. High association does not necessarily mean two devices give interchangeable values, while agreement asks how close their readings are. The registry record does not state which statistical definition of comparison was planned or provide any estimates of association or agreement.
What do significance tests and confidence intervals add?
General statistical principle: a significance test evaluates how compatible the observed data are with a specified null hypothesis under the test’s assumptions. A p-value is not the probability that the null hypothesis is true, and it does not by itself convey the magnitude or practical importance of an effect. A confidence interval expresses uncertainty around an estimate and helps show which effect sizes remain compatible with the data and method. Neither a p-value nor a confidence interval for the primary endpoint or monitor relationships is reported in the registry record. Without an estimate and an uncertainty measure, the precision of the study’s intended findings cannot be assessed.
The planning illustration is described as using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes detectable effects as stated fractions of an observed effect. These are assumptions for a planning illustration, not the registered study design: the study is single-group and observational, and the record says the planning calculation is not the trial’s own design. Sample sizes from such an illustration should be read only as planning scenarios, not as observed power or evidence that the completed study had a particular probability of detecting an effect. The trial’s sample-size justification is not reported in the registry record.
No sponsor analysis is posted for the primary outcome, and no recalculated estimate is available to interpret. In general, a recalculation from summary statistics can differ from an adjusted or prespecified analysis because it may use a different model or omit covariates and design features. There are no such estimates or discrepancies to compare in this record. The analysis methods and any adjustment strategy are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The record describes several related questions: comparing qCON with BIS as hypnosis indexes, assessing qNOX and qCON, assessing qNOX as an indicator of response to nociceptive stimulation, and examining movements as clinical signs. It lists 3 outcome measures and names intraoperative movements as a secondary outcome in addition to the primary movement outcome during LMA insertion. When multiple outcomes or analyses are considered, the chance of finding at least one apparently notable result can increase. General statistical principle: multiplicity methods may be used to control that risk, or investigators may identify a primary hypothesis in advance and interpret other analyses as secondary or exploratory. Any multiplicity procedure, hierarchy of hypotheses, or prespecified analysis plan is not reported in the registry record.
The record does not report the number of participants included in each outcome analysis, the analysis population definition, exclusions, or participant-level missingness. It therefore is not possible to determine whether all enrolled participants contributed to every outcome or how missing measurements were handled. General statistical principle: missingness can affect an estimate when the probability of a value being missing is related to participant characteristics or outcomes. Methods for handling missing data, and any assessment of its possible impact, are not reported in the registry record.
The enrollment is 60, while the adverse-event listing gives 59 at risk. The record does not explain this difference, and the adverse-event count should not be treated as an analysis denominator for the primary endpoint. No participant flow information or analysis-population counts are reported in the registry record. These omissions limit assessment of whether the outcome results, if reported elsewhere, would represent all enrolled participants or a selected subset.
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 |
|---|---|---|---|
| Depth of Anesthesia | 0 | 59 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Depth of Anesthesia | 0 of 59 |
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 |
|---|---|
| Depth of Anesthesia | 0 of 59 |
The adverse-event listing gives 59 participants at risk in the “Depth of Anesthesia” group. It reports 0 participants affected by serious adverse events, 0 affected by other adverse events, and 0 deaths. These are the recorded counts for the group in the registry entry.
These figures should be read as counts in the registry record, not as a detailed safety analysis. The record does not list serious adverse-event terms, and it does not provide event descriptions, timing, severity categories beyond the serious/other distinction, or an analysis relating events to a specific monitor. The reason that the at-risk count is 59 while enrollment is listed as 60 is not reported in the registry record.
General statistical principle: a zero count in a registry listing means no events were recorded in that listing; it does not establish that an event is impossible or characterize risk outside the observed group. With no event-level detail or comparative group, these figures cannot support a comparative safety estimate for qCON-qNOX versus BIS. The study is listed as single-group, with both monitors used in the group.
12. What the Result Does, and Does Not, Mean
The registry record is useful for identifying what the study set out to examine: EEG-based monitoring during general anesthesia, including qCON and BIS indexes of hypnosis and qNOX in relation to responses to nociceptive stimulation. It also specifies a concrete primary outcome, the total number of movements during LMA insertion, and lists a timeframe of approximately 10 minutes. The record indicates that the study is completed and lists enrollment of 60.
Those design details do not substitute for results. No primary movement total, correlation estimate, monitor comparison estimate, confidence interval, or p-value is reported in the registry record. The posted information therefore does not show the direction or magnitude of any relationship between qNOX and movement, or the precision of such a relationship. It also does not establish whether qCON and BIS readings were similar, different, or in agreement.
The study is described as observational and single-group, with both monitors used in the same group and allocation listed as NA. This means the registry does not describe a randomized comparison in which different participants are assigned to different monitor strategies. General statistical principle: observational measurements can describe associations, but an association alone does not establish causation. The record’s stated hypothesis about qNOX and clinical signs should be understood as a research question, not as a demonstrated result.
The endpoint is a group-level count rather than a participant-level count. Without an event total, participant-level data, or a stated method linking monitor readings to movements, the endpoint cannot be used to infer how movements were distributed among participants or how a particular reading corresponded to a response. Further protocol and analysis details—including the statistical plan, missing-data handling, and analysis populations—are not reported in the registry record.
Accordingly, the registered information supports a description of the study’s aims and structure, but not a conclusion about monitor performance or a treatment effect. No medical decision should be inferred from the absence of posted results or from the zero adverse-event counts alone. The registry information is incomplete for evaluating the precision, robustness, and clinical meaning of the intended statistical findings.
13. Why This Trial Matters Statistically
This study raises a statistical question that is distinct from simply comparing device labels: how should monitor readings be related to observed responses during a defined stimulus? The stated objective involving qNOX and movement connects a continuous monitor index with a clinical sign, while the primary endpoint is recorded as a group-level event count. That makes clear outcome definition and analysis structure especially important. The registry record identifies the question but does not report the data or analysis needed to answer it.
The single-group design also matters. Both qCON-qNOX and BIS are described as being used in the same group, rather than assigned in separate groups. General statistical principle: paired or within-participant measurements can support a different comparison from independent groups, and the appropriate uncertainty calculation depends on that structure. The analysis method is not reported in the registry record. The study title’s comparative wording should therefore be interpreted in light of the stated observational design.
The endpoint’s aggregation is another important issue. A total number of movements for the group is not the same as a participant-level rate or probability. General statistical principle: preserving participant-level information can allow analysis of variability and the relation between each person’s measurements and responses. A group total alone cannot show whether events were evenly distributed or concentrated among participants. The registry does not report the primary count or participant-level outcome results.
Finally, this record illustrates why completed status and enrollment alone do not establish an evidential conclusion. Without effect estimates and measures of uncertainty, readers cannot judge magnitude or precision. Without an analysis plan, they cannot determine how the several stated objectives and outcomes were handled. These statistical details are central to evaluating what a completed observational study can establish.
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 registry record does not report results for the primary endpoint or the stated monitor objectives. The group-level movement total, any qNOX correlation estimate, and any qCON-versus-BIS comparison are absent. As a result, neither the direction nor precision of the findings can be assessed from the registered information.
The primary endpoint is specified as a total for the group, not a per-participant outcome. The record does not describe how movement was defined or recorded, how monitor readings were synchronized with the stimulus, or how readings and events were paired for analysis. These details are relevant to interpreting a proposed relationship between qNOX and movement, but are not reported in the registry record.
The study is listed as observational, single-group, and without allocation. Both monitors are described as used in the same group, so there is no separate randomized comparator described. Masking is listed as none. The record does not explain whether outcome assessment was standardized or whether the people recording movement knew the monitor readings.
Although enrollment is listed as 60, the adverse-event listing gives 59 at risk; the reason for the difference is not reported in the registry record. Participant flow, analysis populations, missing outcome data, and methods for handling missingness are also not reported. Statistical methods, any covariate adjustment, and the approach to multiple outcomes are not described. These limitations prevent a full appraisal of the planned or completed analyses.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Comparison of Two Electroencephalograms (EEG) Monitors in Patients Undergoing General Anesthesia — NCT02928172.
- Registry record last updated 2024-05-28; status last verified 2024-05.
- Results first posted 2024-05-24.
- 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
NCT02928172 is listed as a completed, observational study with a single-group design and enrollment of 60. The record describes use of both qCON-qNOX and BIS monitors and lists no allocation and no masking. Its objectives concern hypnosis indexes and qNOX as an indicator of response to nociceptive stimulation. The primary endpoint is the total number of movements for the group during LMA insertion, over an approximately 10-minute timeframe. The registry record does not report the primary outcome result, a correlation estimate, or comparative monitor analyses. It lists 0 serious adverse events, 0 other adverse events, and 0 deaths among 59 participants at risk; the difference between that count and enrollment is not explained.