Train-of-four Monitoring Using the Tetragraph: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Train-of-four Monitoring Using the Tetragraph (NCT04475250), a na na study. The primary outcome is Baseline TOFr (%).

2. Clinical Question

The study concerns monitoring during pediatric surgery, rather than a randomized comparison of treatments. Its stated purpose is to evaluate whether the Tetragraph monitor can be used in this setting and to compare its assessment with the standard visual approach. The registry record does not specify the exact comparison procedure, how paired measurements would be analyzed, or what definition of feasibility would be applied.

The primary endpoint is baseline TOFr: the ratio of the fourth twitch to the first twitch in a train-of-four sequence before administration of the neuromuscular blocking agent, multiplied by 100. The listed secondary outcomes concern baseline amplitude, recovered amplitude, and rate of muscle recovery. No estimates for these outcomes are reported in the registry record. Consequently, the clinical question can be described from the stated objectives and measures, but the posted information does not establish how well the device performed or how its measurements related to visual assessment.

3. Trial Design

This is a prospective study with a planned enrollment of 100 participants. The registry record lists the status as completed, with a start date of 2021-02-01 and a primary completion date of 2023-05-30. The sponsor is Joseph D. Tobias. The condition is surgery, and the study population described in the summary is pediatric patients undergoing surgery.

The listed model is single group, allocation is recorded as NA, and masking is NONE. The only intervention listed is the Tetragraph (TM) NMT Monitor, classified as a device. The registry also names standard visual train-of-four assessment with a peripheral nerve stimulator in the study title and summary, but it does not list a separate standard-assessment arm or provide an arm description for a comparator. The record therefore does not describe a randomized, parallel-group comparison. Details of how the two assessment approaches were to be compared are not reported in the registry record.

The primary outcome is Baseline TOFr (%), defined as a mean with standard deviation and measured immediately prior to the start of surgery. The registry lists five outcome measures, including baseline amplitude, recovered amplitude, and rate of muscle recovery among the secondary outcomes. It does not provide the full details of all outcome measures in the information available for this analysis.

The record lists no analyses. It does not report the protocol’s statistical analysis plan, participant flow, eligibility criteria, monitoring procedures, measurement schedule beyond the primary timeframe, or reasons for any missing observations. These gaps limit assessment of how the planned feasibility evaluation was conducted and how completely the listed outcomes were collected. The completed status and planned enrollment describe the study record, but do not by themselves establish that every planned measure was available for analysis.

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

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 Baseline TOFr (%), measured over Immediately prior to start of surgery.

Baseline TOFr is a continuous measure of the relative size of twitches in a train-of-four assessment. The registry defines the measure as the fourth twitch divided by the first twitch, multiplied by 100, before administration of the neuromuscular blocking agent. The stated measurement time is immediately prior to the start of surgery. The record explains that a lower TOFr corresponds to stronger neuromuscular block and more muscle paralysis.

As a continuous endpoint, the measure retains variation across participants rather than reducing the response to categories such as present or absent. The registry specifies that the primary outcome is summarized using a mean and standard deviation. The mean describes the central value in the measured group, while the standard deviation describes the spread of individual measurements around that mean. These summaries can help characterize baseline responses, but they do not alone establish agreement between two monitoring methods.

The study summary describes a comparison between Tetragraph and standard visual assessment, while the primary endpoint is specifically labeled Baseline TOFr. The record does not state whether this endpoint is intended to quantify agreement, feasibility, or another property of the monitor. It also does not report the observed mean, standard deviation, participant-level data, or a comparison estimate. The endpoint’s definition and intended timing are therefore available, but its observed distribution and its relationship to the visual assessment are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the primary summary describe?

The primary outcome is continuous: baseline TOFr (%) is summarized using a mean and standard deviation. In general, a mean gives a measure of the center of a set of observations. A standard deviation describes how widely observations vary around that center. The pair can characterize a distribution, but does not show all features of the data. For example, these summaries do not by themselves indicate whether the distribution is symmetric or whether unusual observations are present.

The registry record does not report the numerical mean or standard deviation. It also does not report a confidence interval for the endpoint. In general, a confidence interval expresses uncertainty around an estimate under the assumptions of the statistical method used. Its width reflects both the amount of information in the data and the variability of the measure. Without a reported estimate and interval, precision cannot be evaluated for this outcome.

How should a comparison of monitoring methods be evaluated?

In general, two measurement methods can be compared by asking whether their readings are similar for the same participants, whether one method tends to read higher or lower, and whether the differences are small enough for the intended use. Agreement is not interchangeable with correlation: two methods can move together across participants while still producing systematically different readings. The appropriate analysis depends on how measurements were collected, the measurement scale, and the question the study set out to answer.

The record names both Tetragraph and standard visual assessment in its summary, but gives no measurement pairing details and reports no comparison statistic. It does not state whether every participant had readings from both methods, how repeated measurements were handled, or what criterion would define acceptable feasibility or agreement. Thus, general principles explain what a comparison might examine, but the registry record does not identify which such analysis was conducted.

What do the design labels imply?

The record lists a single-group model, allocation as NA, and masking as NONE. These entries do not describe random assignment or masking. The intervention list contains Tetragraph, and the record does not provide a separate comparator arm description. The title and summary nevertheless refer to standard visual assessment. That combination makes the intended comparison understandable at a broad level, but leaves the operational design unclear. It is not appropriate to infer a paired design, a control group, or a specific analytical method from the wording alone.

In general, a study’s design determines which comparisons are supported and which sources of uncertainty matter. A comparison between measurements within participants differs from a comparison between separate groups. The registry record does not provide enough detail to determine which framework applies to the planned comparison, so a method-specific interpretation is not possible.

What can be said about planning calculations?

The record describes planning illustrations based on a fraction of the observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It states that the illustrations are planning calculations, not the trial’s own design. The record’s study design is single group and does not list two arms, so those hypothetical assumptions should not be mistaken for the actual allocation structure.

In general, a planning calculation asks how much information might be needed to detect an effect under specified assumptions. It is not evidence that an effect was observed, and it does not establish the probability that a completed study has found a true effect. The record does not report the observed effect used for the illustrations or numerical planning outputs in the information available for this analysis. These calculations cannot be used to infer the trial’s enrollment rationale or its achieved precision. The sample-size justification for the study itself is not reported in the registry record.

Which statistical details are unavailable?

The registry record lists no analyses. It does not report an analysis plan, outcome estimates, confidence intervals, hypothesis tests, or model specifications. It also does not describe how missing measurements would be handled, whether any adjustment variables were prespecified, or whether assumptions were checked. These details matter because they determine how observed data are translated into estimates and how uncertainty is quantified.

General statistical interpretation must therefore be separated from the study’s actual reported analysis. Means, standard deviations, confidence intervals, agreement measures, and comparisons are concepts relevant to continuous monitoring data; their relevance does not mean that the study calculated or reported them. The available record supports explanation of the endpoint and general analytical issues, but not a reconstruction of unreported methods or results.

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("Tetragraph")
n   <- c(100)
m   <- c(100.1)
sp  <- c(8.4)
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  Tetragraph  100  100.100  8.400  98.433  101.767

11. Multiplicity, Missing Data and Analysis Populations

The registry lists five outcome measures, including Baseline TOFr (%) as the primary outcome and secondary outcomes for baseline amplitude, recovered amplitude, and rate of muscle recovery. The available record does not describe the full set of analyses or say how outcomes were prioritized beyond the primary designation. It does not report whether multiple comparisons were planned or whether any adjustment for multiplicity was specified. In general, conducting multiple statistical tests can increase the chance of obtaining at least one apparently notable result by chance; methods for addressing this depend on the study’s aims and analysis plan. No such approach is reported in the registry record.

The record lists zero analyses and does not provide outcome estimates. It also does not report missing-data counts, reasons for missing measurements, or methods for handling missingness. The number of participants with usable data for each outcome is not reported in the registry record. Without those details, it is not possible to assess whether results, if any, reflect all enrolled participants or a subset with recorded measurements.

Analysis populations are also not described. The record does not state whether analyses would include all enrolled participants, only those with completed monitoring, or another defined group. It does not report exclusions after enrollment or deviations from a protocol. These are distinct from the planned enrollment of 100, which does not establish how many participants contributed to any specific outcome. The protocol’s approach to multiplicity, missing observations, and analysis populations is not reported in the registry record.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

The registry lists the Tetragraph group with 100 participants at risk for serious adverse events and 0 affected. It also lists 100 at risk for other adverse events and 0 affected, with 0 deaths. These figures describe the counts recorded in the registry; they are not estimates of comparative risk because no separate comparator group is listed.

Counts of zero should be read narrowly. They indicate that the registry reports no affected participants in the listed categories. The record does not provide event definitions, the period over which events were collected, the method of surveillance, or information about completeness of reporting. It does not describe whether events were assessed for relationship to the device or procedure. Those details are not reported in the registry record.

Consequently, the posted counts do not establish that no adverse events occurred outside the recorded categories or observation process. They also do not support a comparison with standard visual assessment, since a distinct comparator group and corresponding event counts are not listed. The safety figures are descriptive registry entries and should be interpreted within those limits.

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

The registry record establishes that a prospective study of Tetragraph monitoring in pediatric patients undergoing surgery was marked completed. It gives a planned enrollment of 100, identifies baseline TOFr as the primary outcome, and lists additional outcomes related to muscle amplitude and recovery. It also provides counts for serious adverse events, other adverse events, and deaths in the Tetragraph group.

Those details describe the study’s stated scope and selected registry entries. They do not show the observed primary outcome or the secondary outcome results. No mean, standard deviation, confidence interval, test result, or comparison estimate is reported in the registry record. The posted information therefore cannot establish the distribution of baseline TOFr or quantify the relationship between Tetragraph readings and visual assessments.

The study summary describes a comparison with standard visual train-of-four assessment, but the listed model is single group and no separate comparator arm is described. This limits what can be concluded about comparative performance from the design information alone. The record does not define a feasibility threshold or explain how feasibility would be judged. It is not possible to infer that the device was feasible, accurate, or preferable from the stated study objective or completed status.

The adverse-event entries report zero affected participants in the listed categories, but details on event definitions and ascertainment are absent. These counts do not establish the absence of all harms. Likewise, the listed planning assumptions do not constitute a result or an observed-power analysis; they are described as illustrations rather than the trial’s own design.

In general, a completed study can still have limited interpretability when outcome estimates and analysis methods are not reported. The record supports a careful description of what was intended and what counts were posted, but not a conclusion about the success of monitoring or a quantified comparison between methods.

14. Why This Trial Matters Statistically

This study addresses a statistical issue that is central to monitoring research: whether an instrument’s measurements can be meaningfully compared with an established assessment approach. A study can state an intention to compare methods, but interpretation depends on how measurements are collected and what definition of agreement or feasibility is chosen. The registry record names both Tetragraph and visual train-of-four assessment, while identifying a single-group model and listing only the device intervention. This makes clear why design description and analysis reporting matter alongside an outcome’s name.

The primary outcome is continuous and has a stated summary format, mean and standard deviation. Such summaries can describe the center and spread of measurements, but method comparison generally requires further information about how readings relate to one another. The registry record does not report comparison estimates or analyses. As a result, the methodological question is visible, while the evidence needed to answer it is not available in the posted record.

The listed secondary outcomes also indicate that the study considered amplitude and recovery, not only a baseline ratio. These outcomes could describe different aspects of neuromuscular monitoring, but without estimates, measurement details, or analysis methods, their contribution cannot be assessed. The record’s completed status does not substitute for transparent reporting of results.

More broadly, this case illustrates the distinction between a stated research aim, a registered endpoint, a statistical analysis, and an interpretable result. Each plays a different role. For clinicians and researchers evaluating measurement studies, a clear account of the comparator structure, outcome definitions, missing data, and analytical approach is necessary to understand what the numbers support. Those details are not reported in the registry record, so the statistical importance lies as much in the limits of available reporting as in the intended monitoring question.

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 provides limited detail about the study procedures. Although the summary describes pediatric patients undergoing surgery, eligibility criteria, participant characteristics, and the enrolled sample’s composition are not reported in the registry record. The planned enrollment is 100, but the number contributing data to each outcome is not stated.

The comparison structure is also unclear. The study title and summary refer to standard visual train-of-four assessment, while the model is listed as single group and only Tetragraph appears as an intervention. No separate comparator arm or arm description is posted in the record. Details on whether both methods were applied to the same participants, how measurements were timed, and how comparison results would be interpreted are not reported in the registry record.

The primary outcome is defined and timed, but no estimate or analysis is posted. The record lists five outcome measures and zero analyses. The analysis plan, handling of missing observations, analysis populations, and any multiplicity strategy are not reported in the registry record. The complete measurement schedule and methods for collecting the secondary outcomes are also absent.

Safety reporting is limited to event counts and numbers at risk. Event definitions, ascertainment procedures, observation period, and completeness are not described. Finally, the record does not report a sample-size justification for the actual study. The planning assumptions refer to illustrations using two-arm allocation, whereas the study model is listed as single group; those assumptions should not be treated as evidence of the study’s design or precision. Collectively, these gaps prevent a detailed evaluation of feasibility, comparative measurement performance, and the completeness of outcome reporting.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Train-of-four Monitoring Using the Tetragraph — NCT04475250.
• Registry record last updated 2024-08-12; status last verified 2024-08.
• Results first posted 2024-08-12.
• 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.

19. Record Summary

NCT04475250 is a completed prospective study titled Train-of-four Monitoring Using the Tetragraph. It concerns pediatric patients undergoing surgery and describes evaluation of the Tetragraph neuromuscular transmission monitor in comparison with standard visual train-of-four assessment. Planned enrollment was 100; the record lists a single-group model, allocation as NA, and masking as NONE.

The primary outcome is baseline TOFr (%), summarized by mean and standard deviation immediately prior to the start of surgery. Secondary outcomes include baseline amplitude, recovered amplitude, and rate of muscle recovery. The registry record lists no analyses and does not report outcome estimates. It records 0 serious adverse events, 0 other adverse events, and 0 deaths among the Tetragraph group, with 100 participants at risk in each adverse-event category. Comparative results, analysis details, missing-data information, and further safety-reporting methods are not reported in the registry record.