Heated Humidified Oxygen Compared to Dry Oxygen Therapy in Children With Bronchiolitis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Heated Humidified Oxygen Compared to Dry Oxygen Therapy in Children With Bronchiolitis (NCT02094664), a randomized na study. The primary outcome is Change in Respiratory Distress Assessment Instrument (RDAI) From Baseline..

2. Clinical Question

The study is titled HHOT AIR Study (a Pilot Study) and is registered as NCT02094664. Its stated hypotheses concern oxygenation, work of breathing, and length of hospital stay. Those hypotheses describe the rationale for comparing the oxygen approaches; they do not establish what the posted outcome results show. Length of hospital stay and duration of oxygen use are listed as secondary outcomes, while the primary outcome is the RDAI. Numerical results for these outcomes are not reported in the registry record. The clinical question can therefore be described from the study plan, but the available record does not support a quantitative conclusion about differences between the arms.

3. Trial Design

This is a completed, randomized, parallel-arm pilot study. The registry lists enrollment as 32 and identifies two arms: standard oxygen via nasal cannula and heated and humidified oxygen. Allocation is recorded as randomized, and masking is recorded as none. The record does not report the randomization procedure, whether allocation was concealed, or additional details about the conduct of treatment or outcome assessment.

The study is sponsored by UCSF Benioff Children's Hospital Oakland. The recorded start is 2014-01, and primary completion is 2015-06. The status is completed. The phase field is recorded as NA. The title and brief description place the comparison in infants or children with bronchiolitis, and the conditions include hypoxemia. More detailed eligibility criteria, care setting, and participant characteristics are not reported in the registry record.

The primary outcome is the change in RDAI from baseline, with assessments at Baseline, Hour 1, Hour 4, Hour 8, and Hour 12. The outcome description says absolute scores at each time point are reported for each arm and points to the Baseline Module for baseline scores. Length of hospital stay and duration of O2 use are listed as secondary outcomes. Four outcome measures are recorded, but the number of analyses is listed as 0. Numerical findings and inferential comparisons are not reported in the registry record. Accordingly, the design can be described, but the observed magnitude, uncertainty, and statistical significance of the primary comparison cannot be assessed from the record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

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 Change in Respiratory Distress Assessment Instrument (RDAI) From Baseline., measured over Baseline, Hour 1, Hour 4, Hour 8, and Hour 12.

The primary endpoint is the change in Respiratory Distress Assessment Instrument (RDAI) from baseline. The RDAI is described as a validated clinical scoring system used to assess respiratory distress and as a measure used in several bronchiolitis studies. Its score is based on wheezing and retractions, with points assigned to each. The total score ranges from 0 to 17, and a higher score represents worse clinical respiratory distress.

The outcome is continuous, and the record specifies that results are expressed as a mean with a standard deviation. Measurements are scheduled at baseline and at Hour 1, Hour 4, Hour 8, and Hour 12. The registry outcome description says absolute scores at each time point are reported for each arm. Baseline scores are described as being in the Baseline Module. The numerical scores, changes from baseline, and comparisons between arms are not reported in the registry record.

Repeated assessment can describe how the measured score varies over the early follow-up period, rather than limiting assessment to a single follow-up time. As a general statistical point, interpretation of change depends on the definition of the change measure and on the observations available at each assessment. The registry does not report an analysis specification clarifying whether the primary comparison is based on change scores, a repeated-measures model, or another approach. The rationale and results therefore need to be distinguished: the record explains what the RDAI measures, but does not provide numerical evidence about the outcome.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a randomized, parallel-arm design with no masking. In a randomized study, assignment is intended to create groups whose baseline characteristics are comparable on average, though randomization does not guarantee identical groups in a particular trial. A parallel design means the arms receive their assigned approaches during the same study period rather than each participant serving successively in both arms. These are general descriptions of the design; details of the sequence generation, allocation concealment, and implementation are not reported in the registry record.

What does a mean and standard deviation describe?

The primary outcome is a continuous score, and the registry specifies a mean and standard deviation. In general, a mean describes the central value of observations, while a standard deviation describes how spread out individual observations are around that mean. The two measures answer different questions: the mean describes the group-level average, and the standard deviation describes variation among measured scores. Neither alone gives the uncertainty in a comparison between arms. That uncertainty is usually conveyed through an effect estimate with a confidence interval or another inferential summary, neither of which is reported for the primary outcome in the registry record.

The RDAI is reported as an absolute score at each assessment time. The endpoint title, however, refers to change from baseline. In general, a change score is calculated by relating a participant's follow-up measurement to that participant's baseline measurement. A group mean change is therefore not necessarily recoverable from separate group means unless the relevant values and analysis definitions are available. The record describes baseline scores as being in the Baseline Module, but the numerical baseline and follow-up values are not reported in the registry record. It also does not state how the primary change comparison was modeled.

Why do repeated measurements matter?

The listed assessment schedule includes baseline and four follow-up times: Hour 1, Hour 4, Hour 8, and Hour 12. In general, measurements from the same participant over time are correlated; they are not independent observations. An analysis that uses repeated measurements should account for this within-participant relationship. Different valid approaches may target different quantities, such as change at a selected time or an overall pattern across time. The registry record does not report which approach was used, whether each time point was analyzed separately, or whether a single primary contrast was defined.

Multiple assessment times also raise a general multiplicity question. If many time-specific comparisons are tested, the chance of at least one apparently unusual result can increase unless the analysis plan accounts for the family of comparisons. This general issue does not establish that the study conducted multiple tests or that an adjustment was needed. The registry lists four outcome measures and zero analyses, and does not report a multiplicity strategy or the analyses performed.

How should uncertainty be read?

In general, a confidence interval gives a range of effect values compatible with the data and the assumptions of the analysis. A narrow interval indicates greater precision than a wide interval, although interpretation also depends on the outcome and the question. A p-value, when reported, addresses compatibility of data with a specified null model; it does not measure the probability that a treatment works. No confidence interval or p-value for the primary comparison is reported in the registry record, so precision and statistical evidence cannot be evaluated from the posted record.

The registry includes a description of planning illustrations based on an observed effect. It states assumptions of a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. These are planning assumptions for illustrations, not a report of the trial's own design rationale. The registry does not report the trial's sample-size justification. Any sample-size figures based on these assumptions should be read as planning illustrations, not as observed power or evidence about the outcome. The observed effect used for such an illustration and the resulting numerical planning values are not reported in the registry record.

General statistical interpretation also depends on the population included in each analysis, the handling of missing measurements, and the model's assumptions. For continuous scores, distributional assumptions can matter, especially when samples are limited or data are markedly skewed. A model may also require an appropriate account of repeated observations. These points are general methodological considerations, not a description of methods used in this trial: the analysis model, diagnostics, missing-data approach, and analysis population are not reported in the registry record.

Finally, a statistical comparison is not identical to a clinical interpretation. An estimate can be precise yet small, or imprecise enough to include a range of effects. Determining what magnitude matters requires clinical context and an outcome interpretation, neither of which can be inferred from a design description alone. Because numerical primary results and uncertainty estimates are absent from the registry record, statistical methods can be explained but cannot be applied to reach a result-specific conclusion.

10. Multiplicity, Missing Data and Analysis Populations

The RDAI is assessed at baseline and at Hour 1, Hour 4, Hour 8, and Hour 12. Multiple time points can create multiple opportunities for comparison if each is tested separately. As a general statistical principle, a multiplicity plan clarifies which comparisons are primary and how interpretation accounts for testing more than one hypothesis. The registry record does not report such a plan, a prespecified time-specific contrast, or whether any adjustment was used. The existence of repeated assessments alone does not establish how the investigators analyzed them.

Four outcome measures are listed, and the number of analyses is recorded as 0. This does not provide enough detail to determine whether analyses were not conducted, were not entered in the registry, or were handled elsewhere. The statistical analysis plan is not reported in the registry record. It is also not reported whether the secondary outcomes—length of hospital stay and duration of O2 use—were analyzed or how they related to the primary outcome.

Missing-data handling and analysis populations are not reported in the registry record. In general, missing repeated measurements can affect both the number of observations contributing at each time and the interpretation of change over time. Methods may make different assumptions about why observations are missing and what information remains usable. Without participant flow, missingness information, or an analysis description, the impact of missing data cannot be assessed.

The record does not state whether analyses followed randomized assignment, used another population definition, or included all participants with outcome data. It does not report exclusions from analysis or a method for handling incomplete outcomes. These gaps limit assessment of how the planned comparison was translated into an analysis, independently of the absence of numerical results.

11. Safety Results

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

Other (non-serious) adverse events

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

The registry reports serious adverse event and other adverse event counts separately for Control and Treatment. For Control, the number at risk is 16 for serious adverse events and 16 for other adverse events; the affected counts are 0 in both categories. For Treatment, the number at risk is 16 for serious adverse events and 16 for other adverse events; the affected counts are 0 in both categories.

These entries indicate that the registry reports zero affected participants in the listed event categories for each arm. They do not describe the nature, timing, or ascertainment of adverse events, and the registry lists no top serious-event terms. A reported zero is not the same as proof that an event is impossible or that no unrecorded event occurred. It should be read as a count in the posted safety record, within the categories and information that the registry reports.

The death count is null for both arms. A null entry is not a reported count of zero; the death count is not reported in the registry record. The record also does not provide additional detail about adverse-event definitions, collection procedures, follow-up duration for safety, or whether all randomized participants were assessed in the same way. These counts therefore offer a limited description of the registry's safety entries and should not be extended beyond them.

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

The record establishes that a randomized pilot study compared heated and humidified oxygen with standard oxygen via nasal cannula in infants or children with bronchiolitis. It identifies respiratory distress measured with the RDAI as the primary outcome and specifies assessments from baseline through Hour 12. It also lists length of hospital stay and duration of O2 use as secondary outcomes. These details clarify what the study set out to examine.

The registry does not report numerical outcome results, between-arm estimates, confidence intervals, or p-values. It therefore does not show how the RDAI scores changed, how the arms compared, or how precisely any effect was estimated. The absence of a reported analysis is not evidence that the approaches were equivalent, and it is not evidence that one approach had a better outcome. No efficacy conclusion is supported by the information in the registry record.

The study's stated hypotheses concern oxygenation, work of breathing, and length of hospital stay. Hypotheses express questions to be evaluated; they are not findings. Similarly, the registry's description of a validated RDAI explains the role of the measurement but does not establish a result for the comparison. The secondary outcomes are named, but their observed values are not reported in the registry record.

The safety entries show zero affected participants for the listed serious and other adverse event categories in each arm, with 16 at risk in each corresponding category. Death counts are not reported in the registry record. Those entries should be interpreted narrowly as the posted counts, not as comprehensive evidence about every possible safety outcome.

Overall, the registry supports a description of the trial question, design, outcome schedule, and limited safety counts. It does not support an estimate of treatment effect, a conclusion about statistical significance, or a determination of clinical importance. Such conclusions would require numerical outcome findings and analysis details that are not reported in the registry record.

13. Why This Trial Matters Statistically

This study illustrates why a registry entry can be informative about the research question while remaining insufficient for judging the results. The randomized, parallel design identifies a comparison between two oxygen approaches, and the RDAI gives a defined clinical measure of respiratory distress. Recording assessments from baseline through Hour 12 makes the intended early follow-up structure visible. These features help readers understand what was to be compared and when measurements were planned.

At the same time, the primary outcome title refers to change from baseline while the description specifies absolute scores at each time point. That distinction matters statistically: the analysis of change and the comparison of absolute follow-up scores can answer different questions. Without numerical values or an analysis description, readers cannot determine how the endpoint was operationalized or what the observed contrast was.

The pilot designation and recorded enrollment of 32 also make precision an important consideration, but the record contains no primary effect estimate or confidence interval with which to assess it. General planning illustrations based on an observed effect do not substitute for a trial's own sample-size justification or for an estimate of uncertainty around an observed result. The record does not report the trial's sample-size rationale, and the number of analyses is listed as 0.

Statistically, the entry is a useful reminder to distinguish study aims, outcome definitions, and outcome findings. The hypotheses describe what investigators expected to examine; they are not evidence of what occurred. The study design and measurement schedule can be discussed, but results and their precision cannot be inferred where they are not reported. This distinction is central to responsible reading of clinical trial records.

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.

A central limitation for interpreting this trial from the registry record is the absence of numerical primary outcome results. Although the RDAI outcome and assessment times are described, the means, standard deviations, changes from baseline, and arm-to-arm estimates are not reported. The record therefore does not permit an assessment of the direction, size, or precision of the primary comparison.

The endpoint description says absolute scores are reported at each time point, while the title names change from baseline. The relationship between these presentations and the statistical contrast is not explained. Baseline values are identified as being in the Baseline Module, but their numerical values are not reported in the registry record. The analysis model, handling of repeated measurements, and definition of the primary comparison are also not reported.

Although the record lists four outcome measures, it lists zero analyses. It does not report a multiplicity plan, missing-data methods, analysis populations, participant flow, or exclusions from analysis. The record also does not provide detailed eligibility criteria or participant characteristics that would help assess the population represented. These omissions limit evaluation of both the internal interpretation of the results and the applicability of any findings.

The study is identified as a pilot study, but the registry does not report the trial's sample-size justification. Planning illustrations based on an observed effect are not a substitute for that rationale and do not establish observed power. Safety information is also limited: event counts are reported, but details of ascertainment and follow-up are not, and death counts are not reported in the registry record. These limitations concern what can be concluded from the registry information; they do not establish that unreported procedures or results were absent from other study materials.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Heated Humidified Oxygen Compared to Dry Oxygen Therapy in Children With Bronchiolitis — NCT02094664.
• Registry record last updated 2018-01-08; status last verified 2018-01.
• Results first posted 2018-01-08.
• 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.

18. Record Summary

NCT02094664 is a completed randomized, parallel-arm pilot study sponsored by UCSF Benioff Children's Hospital Oakland. The study compares heated and humidified oxygen with standard oxygen via nasal cannula in infants or children with bronchiolitis. Allocation is recorded as randomized and masking as none. Enrollment is listed as 32; the recorded start is 2014-01 and primary completion is 2015-06.

The primary outcome is change in RDAI from baseline, with scheduled assessments at Baseline, Hour 1, Hour 4, Hour 8, and Hour 12. Length of hospital stay and duration of O2 use are listed as secondary outcomes. Numerical primary and secondary outcome results and statistical analyses are not reported in the registry record. Serious and other adverse-event affected counts are 0 in both arms; death counts are not reported.