Image Guidance for Improved Vessel Cannulation in Pediatric Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Image Guidance for Improved Vessel Cannulation in Pediatric Patients (NCT04031495), a na na study. The primary outcome is Successful Central Vein Cannulation.

2. Clinical Question

3. Trial Design

This was a completed, single-site pilot and feasibility study of image-guided central vein cannulation in pediatric patients. The registry lists a single-group model, with an enrollment of 9. The intervention was central vein cannulation using the Clear Guide SCENERGY system. No separate comparison group is described, and allocation is listed as NA. Masking is listed as NONE.

The registry summary describes performance by an expert operator in Interventional Radiology who routinely performs central venous catheter placement. It states that the study would use pediatric human anatomy and vessel size and real patient care scenarios. The arm description likewise identifies the system as being used for central venous catheter placement in pediatric patients. The registry does not report further operational details, such as the number of operators or a fuller account of how cannulation procedures were conducted.

The recorded start date is 2019-04-22, and the primary completion date is 2019-05-10. The study status is COMPLETED. The phase is listed as NA. The registry identifies Clear Guide Medical as the sponsor and Central Vein Cannulation as the condition and intervention.

The design is suited to describing whether the device-assisted procedure was feasible in the study setting, but the single-group structure does not establish how outcomes compare with another approach. The registry record does not report a randomized allocation, a control arm, or a masking procedure. It also does not report a protocol-level statistical plan or a sample-size justification for the enrolled cohort. A study described as a pilot or feasibility study should therefore be read in terms of the process and outcome it registered, without treating it as a comparative effectiveness trial.

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 Successful Central Vein Cannulation, measured over 1 day.

The primary endpoint is titled Successful Central Vein Cannulation. It is defined as a count of participants, with a timeframe of 1 day. Its description focuses on device-enabled successful cannulation on the first pass and presents that outcome as evidence relevant to feasibility in aiding central venous catheter placement.

A first-pass success measure records whether the specified procedural outcome occurred without a later pass being needed. In general, a binary participant-level endpoint is useful for an early feasibility study because it gives a direct count of participants who meet a clearly described success criterion. It can help characterize whether a procedure was achieved in the intended setting. It does not, by itself, explain why a procedure succeeded or failed, and it does not establish how outcomes would compare with another method.

The registry identifies one outcome measure, but does not report the number of participants with successful first-pass cannulation, the number without that outcome, or an estimated success rate. The registered endpoint is therefore clear in its general purpose, while the observed endpoint result is not reported in the registry record. The posted information also does not report further operational criteria for defining success, such as how the first pass was determined or adjudicated. Without those details and the actual outcome count, readers cannot assess the observed frequency or the precision of an estimate from the study.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count represent?

The primary endpoint is a count of participants meeting the registered definition of successful central vein cannulation on the first pass. For a binary outcome, each participant is classified as having or not having the event of interest. A count gives the number in the event category; by itself, it is not the same as a rate or a comparative effect. To interpret a count as a proportion, the denominator and the outcome count both need to be available. The registry gives an enrollment of 9 but does not report the primary outcome count, so the observed proportion cannot be described from the registry record.

What can a confidence interval say?

General explanation: a confidence interval expresses the uncertainty around an estimated quantity under a specified statistical procedure. For a binary outcome, an interval around a success proportion can indicate how precisely that proportion has been estimated. A limited amount of participant information usually leaves greater uncertainty than a larger evidence base, though the exact precision depends on the observed outcome and the method used. No confidence interval or primary outcome estimate is reported in the registry record, so there is no interval to interpret for this study.

Why does the study design matter?

The registry lists a single-group model and no randomized comparison. In general, a single-group outcome can describe the observed experience under the study intervention, but it does not estimate a treatment contrast against a control group. Even a precise estimate in one group would not answer a comparative question without an appropriate comparator. The registry describes the study as a pilot and feasibility study, which aligns the stated first-pass endpoint with an assessment of whether the procedure can be carried out in the study setting. It does not transform the design into a comparative trial.

The description identifies an expert operator in Interventional Radiology who routinely performs central venous catheter placement. That detail locates the feasibility assessment in an experienced-operator setting. It should not be generalized into an assumption about performance by other operators; the registry record does not report results across operators or settings. The record also does not report masking beyond listing masking as NONE, or provide a detailed account of outcome assessment.

What do the planning illustrations mean?

General explanation: sample-size planning asks how many participants or events a future design might require under stated assumptions about the outcome, the effect to detect, and the statistical procedure. Such planning is distinct from the results observed in a completed study. The planning assumptions associated with this record describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They describe an effect to detect as a stated fraction of the observed effect. For time-to-event planning, the assumptions refer to a total event count using the Schoenfeld method; other planning outputs are described as participants per arm.

Those assumptions are planning illustrations, not a description of the registered study design. The registered study is single-group and has no like-for-like control arm, whereas the planning assumptions describe equal allocation between two arms. The illustrations should therefore not be read as evidence that this study enrolled two arms, nor as the study's original sample-size justification. The registry record does not report a trial-specific sample-size justification. The illustrations are not observed power: they do not describe the probability that this completed study detected an effect, and they do not replace an estimate with uncertainty based on the actual outcome.

The record does not provide the primary outcome count or an effect estimate on which to base a study-specific interpretation of the planning assumptions. No computed planning values are reported in the registry record. It is therefore not possible to judge from the registry information whether the enrollment was adequate for a particular precision target or a particular future comparison.

What is not available for statistical assessment?

The registry lists zero analyses. It does not report an inferential method, an adjusted analysis, a confidence interval, or a p-value for the primary outcome. It also does not report the handling of missing outcome data or a prespecified analysis population. These omissions limit the statistical questions that can be evaluated: the observed event frequency, its uncertainty, and any planned handling of incomplete observations are all unknown from the registry record.

General explanation: an analysis plan helps readers understand which outcome definitions and statistical methods were intended before results were examined. It can also clarify how missing observations, protocol deviations, and multiple outcomes are handled. Without those details, readers should avoid inferring a method from the endpoint title or from the study's feasibility label. The registered endpoint and design can be described, but the analysis cannot be reconstructed from the information in the registry record.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Vessel Cannulation With Scenergy")
n      <- c(9)
events <- c(9)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Vessel Cannulation With Scenergy  9  9  100.0  66.4  100.0  70.1  100.0  69.2  99.7

11. Multiplicity, Missing Data and Analysis Populations

The registry identifies one primary outcome measure, Successful Central Vein Cannulation, and lists zero analyses. It does not report statistical tests or a family of confirmatory hypotheses. A multiplicity adjustment is therefore not described in the registry record. It would be inappropriate to infer that a particular adjustment was planned or used, or that none was needed, solely from the outcome count.

General explanation: multiplicity arises when several outcomes, comparisons, or repeated tests are considered together. If multiple tests are used to make confirmatory claims, the chance of a misleading positive finding can increase unless the analysis plan addresses that issue. The registry information does not describe interim analyses or any strategy for managing multiple testing. Those details are not reported in the registry record.

The record does not report how missing primary outcome data would be handled, whether any participants were excluded from the outcome analysis, or how the analysis population was defined. Enrollment is listed as 9, but the primary endpoint result is absent, so the number with evaluable outcome data is not reported in the registry record. Enrollment should not be assumed to equal the analysis denominator.

General explanation: missingness can affect interpretation when the availability of an outcome is related to participant characteristics or the outcome itself. An analysis plan may specify how incomplete data are handled and which participants contribute to an estimate. Without those details, readers cannot determine whether missing observations could have changed the reported result. The registry record also does not report protocol deviations or a distinction between enrolled and analyzed participants.

Because the endpoint result, analysis method, and analysis population are not reported, the registry record does not support a detailed appraisal of multiplicity or missing-data procedures. This is a limitation of the available statistical account, not evidence that a particular procedure was or was not followed.

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 9 participants at risk for serious adverse events and 0 participants affected. It also lists 9 participants at risk for other adverse events and 0 affected, with 0 deaths. These are counts recorded for the group titled Vessel Cannulation With Scenergy.

A count of zero means that no affected participants are recorded in that category in the posted safety information. It does not establish that the risk is absent or that the procedure is free of adverse events. In a small cohort, an event that was not observed can still be possible outside the observed participants. The counts also do not describe the nature, timing, severity, or relationship of individual events beyond the categories and figures recorded.

The registry record does not report a safety follow-up duration or additional narrative about event ascertainment. It is therefore not possible to determine from these counts how long participants were monitored or how adverse events were collected. The figures are best read as the recorded safety counts for this cohort, not as a precise estimate of risk in a wider population and not as a comparison with another approach.

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

The registered study asks a focused feasibility question: whether the Clear Guide SCENERGY system could aid central vein cannulation in pediatric patients, with first-pass successful cannulation specified as the primary outcome. The registry gives the study design, intended endpoint, timeframe, and enrollment. It does not give the number of participants who met the primary endpoint, so the central outcome cannot be quantified from the registry record.

The record does establish that the study was completed and describes a single-site, single-group setting involving an expert Interventional Radiology operator who routinely performs central venous catheter placement. This provides context for the intended feasibility assessment. It does not establish how the system would perform in different settings or among operators with different experience. Those questions are not answered by the registry information.

The absence of a comparator also limits what can be inferred. Without a control group, the registered design does not estimate a difference between the device-assisted procedure and another approach. It cannot isolate the device's contribution to a procedural outcome. The study's feasibility framing and first-pass endpoint should not be mistaken for a comparative test.

The posted safety counts record no serious adverse events, other adverse events, or deaths among the listed participants at risk. Those counts describe what is recorded for this cohort; they do not prove that risk is zero. The registry does not provide enough detail to characterize the duration or process of safety monitoring.

Overall, the record supports a description of the study question and design, but not a conclusion about the observed first-pass success frequency or its precision. A result, confidence interval, and analysis are not reported in the registry record. The study's completion status does not fill those gaps. The distinction is important: a clearly specified endpoint is not itself an outcome result, and a feasibility study without a comparator cannot establish a relative treatment effect.

14. Why This Trial Matters Statistically

This study is statistically notable for the gap between a clearly identified feasibility endpoint and the absence of a posted endpoint result. The registry specifies successful central vein cannulation on the first pass, counted among participants over 1 day. Yet it does not report the number of participants meeting that definition or an analysis. Without those values, readers cannot estimate the observed frequency or judge its precision.

The single-group design is also important. It can organize observation of a procedure in a defined setting, but it does not create a direct estimate of difference versus a control. Recognizing this distinction prevents a feasibility outcome from being interpreted as a comparative claim. The expert-operator setting is relevant to the scope of what the study could describe, while the record does not report evidence across other operators or sites.

The registry also makes a useful distinction between the study itself and the planning assumptions associated with sample-size illustrations. The assumptions describe equal allocation between two arms and a normal approximation, whereas the registered study is single-group. Planning scenarios are not an account of the trial's actual allocation, do not represent observed power, and do not substitute for results from the enrolled participants.

Finally, the safety counts are descriptive. They report zero affected participants in the listed categories among the participants at risk, but cannot establish the absence of risk beyond the cohort or the unspecified monitoring period. Together, these features show why interpreting clinical trial statistics requires attention to endpoint reporting, study structure, planning assumptions, and the limits of event counts.

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 principal limitation for interpreting this study is that the registry record does not report the primary endpoint result. Although successful first-pass cannulation is defined as the outcome, the number of participants meeting the definition and any estimate of uncertainty are not reported. The registry lists zero analyses, so no statistical result is available to evaluate.

The single-group, single-site design does not provide a like-for-like control comparison. The registry describes an expert Interventional Radiology operator who routinely performs central venous catheter placement, but does not report how outcomes might vary by operator or setting. The record also does not provide further participant characteristics or detailed eligibility criteria. These omissions constrain interpretation of how broadly the study experience might apply.

The outcome definition is described in general terms as device-enabled successful cannulation on the first pass. More detailed operational criteria and the process for assessing or adjudicating success are not reported in the registry record. The timeframe is listed as 1 day, but additional details about outcome collection are not reported.

The registry does not report a trial-specific sample-size justification, statistical analysis plan, analysis population, handling of missing outcomes, protocol deviations, or interim analyses. It also does not report whether all enrolled participants contributed evaluable primary endpoint data. These gaps prevent assessment of precision, missing-data effects, and the relationship between the registered outcome and any analysis.

Safety interpretation is limited by the absence of a reported follow-up duration and detailed event descriptions. The recorded zeros are counts for this cohort, not evidence that adverse events are impossible. Finally, planning assumptions associated with sample-size illustrations do not match the registered single-group design and should not be treated as the trial's original design or as observed power.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Image Guidance for Improved Vessel Cannulation in Pediatric Patients — NCT04031495.
• Registry record last updated 2026-07-30; status last verified 2019-07.
• Results first posted 2026-07-30.
• 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

The registry record describes NCT04031495, Image Guidance for Improved Vessel Cannulation in Pediatric Patients, as a completed, single-site pilot and feasibility study. Enrollment was 9, and the intervention was central vein cannulation using the Clear Guide SCENERGY system. The study was intended for pediatric patients undergoing central venous catheter placement, with an expert Interventional Radiology operator described in the summary.

The primary outcome was Successful Central Vein Cannulation, defined as a participant count focused on device-enabled success on the first pass over 1 day. The primary outcome result and statistical analysis are not reported in the registry record. The design is single-group, with no separate comparator described.

The posted safety information lists 0 serious adverse events, 0 other adverse events, and 0 deaths among the 9 participants at risk in the relevant categories. The registry does not report further safety follow-up details. The recorded start date was 2019-04-22, and the primary completion date was 2019-05-10.