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 Helium-oxygen Gas Mixtures Delivered by a High Flow Nasal Cannula in Bronchiolitis (NCT02373683), a randomized na study. The primary outcome is Respiratory Assessment Score.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02373683 |
| Phase | NA |
| Condition | Bronchiolitis, Heliox, Pediatrics |
| Allocation | Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 10 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Case Western Reserve University |
| Results posted | Yes |
2. Clinical Question
Population
Children ages 0-24 months with severe bronchiolitis were the intended population. The intervention description concerns patients following separation from mechanical ventilation, and the primary outcome baseline was defined as within 15 minutes of extubation.
Intervention
The intervention was Vapotherm-Heliox: a mixture of 70% oxygen and 30% helium delivered with a heated, humidified, high-flow nasal cannula system. The study aimed to assess this delivery approach in the clinical setting described by the record.
Comparator
The listed comparator was Standard Care, described as care dictated by the clinical team. The record labels allocation as randomized but also labels the study model as single group. It does not explain this difference, so the intended comparison should be interpreted cautiously.
Primary question
The primary outcome was change in respiratory assessment score from baseline to 48 hours after extubation. The score ranges from 0 to 12, with higher scores indicating worsening respiratory distress. The registry states that the study was terminated early, data were not collected, and results were not analyzed. Thus, the record does not answer whether scores changed or how the intervention compared with standard care.
3. Trial Design
This was a prospective pilot study of a device intervention in children with severe bronchiolitis. The registry lists enrollment as 10 and study status as terminated. The recorded start was 2014-12 and primary completion was 2015-11. The study phase is listed as not applicable.
The allocation field says randomized, and the masking field says none. Separately, the study model is listed as single group. The record also describes both a Vapotherm-Heliox intervention and a Standard Care group. These design descriptions are not fully consistent, and the registry does not clarify how participants were assigned or how the groups were intended to be compared. It is therefore not possible to give a definitive account of the implemented comparison from this record alone.
The intervention description specifies heliox delivered after separation from mechanical ventilation, using the Vapotherm heated, humidified, high-flow nasal cannula system. The Standard Care description leaves care to the clinical team. That description does not specify a common care protocol or list particular co-interventions.
The study was terminated early. The reason for termination, the planned recruitment target, and any sample-size justification are not reported in the registry record. The primary outcome entry explicitly says data were not collected and results were not analyzed. The record lists five outcome measures and zero analyses. It therefore documents a study plan and limited safety counts, but not an analyzed efficacy comparison.
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 | Vapotherm-Heliox | Standard Care |
|---|---|---|
| STARTED | 6 | 4 |
| COMPLETED | 6 | 4 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Study was terminated early. Data were not collected and results were not analyzed.
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.
Population: Data was not collected or analyzed for enrolled patients.
| Characteristic | Unit | Vapotherm-Heliox | Standard Care | Total |
|---|---|---|---|---|
| Participants analysed | 6 | 4 | 10 | |
| Age, Continuous | months | — | — | — |
| Sex/Gender, Customized | Participants | 0 | 0 | 0 |
| Race and Ethnicity Not Collected | Participants | — | — | 0 |
| Primary diagnosis | Participants | 0 | 0 | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Respiratory Assessment Score, measured over 48 hours.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was change in respiratory assessment score from baseline, defined as within 15 minutes of extubation, to 48 hours after extubation. The score ranges from 0 to 12; higher scores indicate worsening respiratory distress. A change score is intended to describe how a measured condition moves over a specified period, rather than relying only on a single measurement at one time.
In general, a respiratory assessment score can provide a structured way to summarize signs of respiratory distress. Repeating the assessment after extubation gives a planned follow-up point for evaluating the course of those signs. The clinical meaning of a change depends on how the score is constructed, how consistently it is assessed, and how much change is important to patients and clinicians. Such interpretive details are not reported in the registry record.
The registry does not give a baseline score, a follow-up score, a change estimate, or a measure of uncertainty. It states that the study was terminated early, data were not collected, and results were not analyzed. Consequently, the endpoint is described as a planned measure, not as an observed outcome in this trial.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central result is the absence of an analyzed primary outcome, rather than evidence for or against an effect. The registry states that the study was terminated early and that respiratory assessment score data were not collected. It reports no change estimate from baseline to 48 hours after extubation and no uncertainty interval or hypothesis test for that outcome. The record therefore cannot quantify the direction, size, or precision of an intervention effect.
The distinction between a planned endpoint and an observed result matters. The score was intended to measure respiratory distress over time, with higher scores indicating worsening distress. But without measurements, there is no observed trajectory to interpret. A treatment comparison cannot be recovered from the outcome description, the enrollment field, or the study's planned timing.
The record includes a randomized allocation label, an unmasked design label, and a single-group model label. It also describes Vapotherm-Heliox and Standard Care. Because these descriptions do not align clearly, the analysis structure that was intended or implemented is not established by the record. Even if allocation had been randomized as planned, randomization alone would not supply the missing outcome data or an effect estimate.
Four secondary outcomes are listed: need for reintubation, PICU length of stay, hospital length of stay, and length of treatment with supplemental oxygen. The record does not provide analyzed results for these outcomes. Their listing indicates topics the study planned to assess, not findings about their frequency or duration.
The record reports safety counts for the listed groups, including zero serious adverse events and zero other adverse events in the reported at-risk counts. Those counts should be read as limited registry entries, not as a complete assessment of safety. Details such as the adverse-event observation period and event collection procedures are not reported in the registry record. Death counts are also not reported in the registry record.
Overall, the posted record supports a description of the study plan, its early termination, and its limited reported safety figures. It does not support a conclusion about whether heliox changed respiratory assessment scores or any listed secondary outcome. The reason for termination is not reported, so no explanation for the missing efficacy results should be inferred.
9. Statistical Methods Explained
The registry describes a planned clinical study but does not contain analyzed primary outcome data. General statistical concepts can help explain what the planned endpoint and design would ordinarily be used to assess; they do not substitute for results that were not collected.
What does a change score represent?
In general, a change score is the follow-up measurement compared with a participant's baseline measurement. It describes movement over time on the chosen scale. Here, the planned comparison was between a baseline respiratory assessment within 15 minutes of extubation and an assessment 48 hours after extubation. The score ranges from 0 to 12, and higher values indicate worsening respiratory distress. A change could describe improvement or worsening depending on its direction, but the record supplies no scores from which to determine either.
Change scores are useful when the question concerns how a condition evolves from a starting point. Their interpretation depends on the reliability of the measurements, the timing of assessments, and the meaning of the scale. General statistical practice also distinguishes a within-group change from a difference in change between groups. A change within an intervention group alone does not establish that the intervention caused the change; a suitable comparator and analysis are needed to separate treatment effects from changes that may occur over time or with other care.
What would an effect estimate and confidence interval tell readers?
In general, an effect estimate describes the observed contrast relevant to the study question. A confidence interval describes the range of values reasonably compatible with the data under the statistical method used. A narrow interval indicates greater precision than a wide interval, while an interval that includes effects in different directions may leave substantial uncertainty about the result. These are general explanations, not descriptions of analyses performed in this trial. The registry reports no primary outcome estimate or confidence interval.
A p-value, in general, measures how surprising data would be under a specified null hypothesis and statistical model. It does not measure the size or clinical importance of an effect, and it does not establish that a result is true or false. No primary outcome p-value is reported in the registry record. Without outcome data and a stated analysis, there is no trial-specific test to interpret.
How should the design labels be read?
Random allocation, in general, is intended to make assigned groups comparable on average, reducing the influence of baseline differences on a treatment comparison. Masking can reduce some forms of bias in assessment or care. This record labels allocation as randomized and masking as none, but it also labels the model as single group while describing an intervention group and a Standard Care group. The record does not resolve this inconsistency or describe the allocation procedure, so the realized design cannot be reconstructed confidently.
A single-group study and a comparative study answer different questions. A single-group assessment can describe outcomes after an intervention, but it generally cannot separate intervention effects from other explanations for change. A comparative design can estimate a contrast between care approaches if the groups, outcome assessment, and analysis are adequately specified. The available design labels do not establish which analysis was planned or carried out.
What do the planning assumptions mean?
General sample-size planning uses assumptions about the effect worth detecting, outcome variability, significance level, allocation, and analysis method. The registry's planning description refers to a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; it also describes planning illustrations based on fractions of an observed effect. Such calculations are hypothetical planning aids, not observed power and not trial results. Since the primary outcome data were not collected, the record provides no observed primary effect from which to judge those illustrations. The trial's own sample-size justification is not reported in the registry record.
Over-dispersion is a general concern for some outcomes, especially counts, when their variability exceeds what a simple model assumes. It can affect standard errors and the precision of estimates. The record does not provide analyzed outcome distributions or a statistical model for the listed outcomes, so it is not possible to assess whether over-dispersion applied or how it was handled.
Finally, statistical methods are interpretable only in relation to the data and analysis population to which they apply. The primary entry says data were not collected and results were not analyzed, and the record lists zero analyses. The analysis population, missing-data procedures, and detailed statistical plan are not reported in the registry record. No method can recover an endpoint effect in the absence of the recorded measurements.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists five outcome measures: the respiratory assessment score, need for reintubation, PICU length of stay, hospital length of stay, and length of treatment with supplemental oxygen. Considering multiple outcomes can raise a multiplicity issue: when several hypotheses are tested, the chance of at least one apparently notable result can increase. In general, a study may address this by prespecifying a primary outcome and an analysis strategy for secondary outcomes. The record identifies a primary outcome, but a multiplicity adjustment or broader testing plan is not reported in the registry record.
For the primary outcome, missingness is not described as a subset of unavailable measurements: the record states that the study was terminated early, data were not collected, and results were not analyzed. Results for the listed secondary outcomes are also not reported. The registry does not explain whether any data for those outcomes were collected, or give reasons for their absence.
In general, missing-data methods depend on why measurements are missing and on what information remains available. No imputation method, sensitivity analysis, or other missing-data procedure is reported in the registry record. The analysis population is also not reported. The record does not specify whether an intention-to-treat, per-protocol, or other population was planned or used.
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 |
|---|---|---|---|
| Vapotherm-Heliox | 0 | 6 | 0.0% |
| Standard Care | 0 | 4 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Vapotherm-Heliox | 0 of 6 |
| Standard Care | 0 of 4 |
The registry lists six at risk in the Vapotherm-Heliox group and four at risk in the Standard Care group. It reports zero serious adverse events and zero other adverse events for each listed group. These are the safety counts recorded for the groups; they do not provide details about the types of events, the observation period, or how events were collected or classified.
The serious adverse event terms list is empty. Death counts are not reported in the registry record. The absence of reported events in these entries should not be interpreted as proof that no events occurred outside the record's collection or reporting process. The record does not describe monitoring completeness, definitions, or follow-up duration for adverse events.
These figures are separate from the missing primary outcome. They do not establish a respiratory assessment score effect, and they are not a full safety analysis. They should be read narrowly as the event counts and at-risk counts registered for the named groups.
12. What the Result Does, and Does Not, Mean
The study aimed to evaluate heliox delivered through a heated, humidified high-flow nasal cannula in children with severe bronchiolitis. Its planned primary endpoint was change in respiratory assessment score from baseline to 48 hours after extubation. The registry records that the trial was terminated early and that data were not collected and results were not analyzed.
As a result, the record does not establish whether respiratory assessment scores improved, worsened, or stayed similar. It does not estimate a difference between Vapotherm-Heliox and Standard Care, and it does not establish the magnitude or precision of any such difference. The same limitation applies to the listed secondary outcomes, for which analyzed results are not reported.
This lack of an efficacy result is not evidence that the intervention has no effect, nor is it evidence that it has an effect. It reflects the absence of analyzed outcome data in the registry record. The reason the study was terminated is not reported, and the reason should not be inferred from the missing results.
The registry does contain limited adverse-event counts. Those entries report zero serious and zero other adverse events among the listed at-risk counts, but the record does not supply enough information about event collection and follow-up to treat those figures as a comprehensive safety assessment. Death counts are not reported in the registry record.
The design fields also need cautious reading: allocation is labeled randomized, while the model is labeled single group, and both an intervention and a Standard Care group are described. Without clarification, the intended comparison cannot be fully reconstructed. The record is informative about the proposed study question and its status, but it does not support a treatment-effect conclusion.
13. Why This Trial Matters Statistically
This trial matters statistically because it illustrates the distinction between a registered study plan and an estimable result. The record identifies a clinical question, a score, assessment timing, and listed secondary outcomes. Those details describe what investigators intended to measure. They do not amount to observations or an analysis.
When a study ends before outcome data are collected, statistical precision cannot be assessed from the planned endpoint alone. There is no estimate to accompany a confidence interval, no outcome comparison to test, and no basis for judging the observed size of an effect. A planned sample-size exercise cannot replace those missing quantities. Planning illustrations based on an observed effect are especially difficult to interpret when the primary outcome entry says no data were collected.
The record also shows why design fields need to be interpreted together. Randomized allocation and a single-group model convey different structural information, while the descriptions name both an intervention and Standard Care. Without clarification, readers cannot confidently identify the implemented analysis structure. Transparent alignment among design, groups, outcomes, and analysis is essential for understanding what a trial can estimate.
Finally, safety counts and efficacy results answer different questions. Limited event counts can be reported even when the primary outcome is unavailable, but they cannot establish an effect on respiratory distress or serve as a complete account of safety. Reading each registry entry within its scope helps prevent missing efficacy results from being mistaken for either a positive or negative finding.
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 principal limitation is that the primary outcome was not collected and no results were analyzed after early termination. The registry therefore provides no respiratory assessment score values, change estimate, or statistical uncertainty. The reason for termination is not reported in the registry record.
There is a design-description inconsistency: allocation is labeled randomized, the model is labeled single group, and the record describes both Vapotherm-Heliox and Standard Care. The registry does not explain the discrepancy or document how allocation was implemented. This limits interpretation of the intended comparison.
The record lists four secondary outcomes but gives no analyzed results for them. It does not report an analysis plan, multiplicity strategy, analysis population, missing-data methods, or a sample-size justification. Those omissions prevent assessment of how outcomes would have been selected, compared, or interpreted.
Safety information is limited to at-risk and event counts. Definitions, follow-up duration, ascertainment procedures, and death counts are not reported in the registry record. The registry also does not describe the score's assessment procedures or the clinical meaning of a given score change. These limitations restrict what can be concluded from the record beyond its stated study plan, status, and recorded safety figures.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Helium-oxygen Gas Mixtures Delivered by a High Flow Nasal Cannula in Bronchiolitis — NCT02373683.
- Registry record last updated 2022-03-02; status last verified 2022-02.
- Results first posted 2022-03-02.
- 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
NCT02373683 is a prospective pilot study titled “Helium-oxygen Gas Mixtures Delivered by a High Flow Nasal Cannula in Bronchiolitis,” sponsored by Case Western Reserve University. The registry lists enrollment as 10, allocation as randomized, masking as none, and the model as single group. The study status is terminated; the recorded start was 2014-12 and primary completion was 2015-11.
The planned intervention was Vapotherm-Heliox, and Standard Care was also described. The primary outcome was change in respiratory assessment score from baseline to 48 hours after extubation. The record states that the study ended early, data were not collected, and results were not analyzed. It lists four secondary outcomes and reports limited adverse-event counts, but no analyzed efficacy findings.