Effect of High Velocity/Hyperoxic Breathing Therapy on Blood Lactate Decline: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effect of High Velocity/Hyperoxic Breathing Therapy on Blood Lactate Decline (NCT05984186), a randomized na study. The primary outcome is Blood Lactate Change.

2. Clinical Question

The clinical question concerns short-term physiological responses during recovery from a Wingate-type exercise test. The primary outcome is blood lactate change, measured at rest and at specified times during recovery. The study also lists respiratory rate, heart rate, oxygen saturation, systolic and diastolic blood pressure, and perceived exertion as secondary outcomes. These measures describe different aspects of recovery; they should not be treated as interchangeable evidence for the primary lactate question.

Because the study uses a crossover structure, its central comparison is between therapy settings experienced within the repeated-measures design, rather than a simple comparison of separate treatment groups. The registry record does not report the sequence in which settings were given, whether a no-therapy condition was included, or how the comparisons were statistically defined. It also does not report results for lactate or the secondary outcomes. The registry therefore describes the question being studied, but does not establish the size or precision of any difference among settings.

3. Trial Design

The registry record identifies a randomized, unmasked crossover study of High Velocity Therapy. It reports enrollment of 15 and a completed study status. The listed start date is 2023-03-06, and the primary completion date is 2023-07-31. The listed phase is NA. Vapotherm, Inc. is identified as the sponsor.

The design description says that the study uses repeated measures and evaluates participants with HVT at four flow and FiO2 settings during the Wingate exercise test and recovery interval. The settings are FiO2=100% with Flow=5LPM, FiO2=21% with Flow=25-35LPM, FiO2=100% with Flow=25-35LPM, and FiO2=21% with Flow=5LPM. In a crossover design, repeated measurements can allow comparisons within participants, which can account for some between-participant variability. That general advantage does not remove the need to account for the dependence between measurements from the same participant.

Randomization is reported, but the randomization method, assignment sequence, and concealment procedures are not reported in the registry record. Masking is listed as none. The record does not describe a washout interval, the order of settings, or methods for addressing possible period or carryover effects. It also does not state whether there was a separate control condition. These details matter for interpreting how directly differences can be attributed to the settings rather than to test order, repeated exercise, or other changes over time.

The brief study summary describes four study segments corresponding to four therapy settings. The registry record does not provide enough detail to characterize the exact conduct of each segment beyond the repeated-measures description. It reports no outcome analyses, estimates, or statistical comparisons. Thus, the design information establishes the intended structure and outcomes, while the posted record does not give the results needed to evaluate the observed responses.

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.

FiO2=100% With Flow=5LPM

FiO2=21% With Flow=25-35LPM

FiO2=100% With Flow=25-35LPM

FiO2=21% With Flow=5LPM

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 Blood Lactate Change, measured over At rest (TR) and during recovery from the Wingate test at minute 2 (T2) minute 4 (T4), minute 6 (T6), minute 8 (T8), minute 10 (T10) minute 15 (T15), minute 20 (T20), minute 25 (T25), minute 30 (T30) minute 40 (T40), minute 50 (T50) minute 60 (T60)..

The primary endpoint is Blood Lactate Change, expressed in mmol/L. The registry record describes it as the change in blood lactate starting from the exercise test throughout the recovery period. Measurements are specified at rest (TR) and during recovery at minute 2 (T2), minute 4 (T4), minute 6 (T6), minute 8 (T8), minute 10 (T10), minute 15 (T15), minute 20 (T20), minute 25 (T25), minute 30 (T30), minute 40 (T40), minute 50 (T50), and minute 60 (T60).

Blood lactate is used as a continuous physiological measure of the recovery response after exercise. Repeated measurements across recovery can describe its time course, rather than reducing recovery to a single observation. The registry specifies that the outcome is summarized as a mean with standard deviation. It does not provide actual means, standard deviations, changes by setting, or between-setting comparisons, so the direction, size, and precision of any observed response cannot be determined from the registry record.

The description does not fully specify the calculation used to derive change at each time point, including the precise reference value or analysis contrast. That operational detail is not reported in the registry record. The outcome label and timing identify what was intended to be measured, but they do not by themselves show how the measurements differed among settings.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a continuous outcome summarized as a mean and standard deviation. The mean represents the average measured value or change for a group or condition. The standard deviation describes variation among measurements around that mean. It is not a measure of the uncertainty in the estimated mean, and it does not show the range of responses for every participant. The registry record does not provide the actual mean or standard deviation values for blood lactate.

What does the crossover structure imply?

In a crossover study, participants are measured under more than one condition, so observations from the same participant are related. General statistical practice accounts for that within-participant correlation when estimating differences and their uncertainty. A repeated-measures analysis can make use of the paired structure, but the method must match the design and the scientific contrast. The registry record describes repeated measures across four therapy settings; it does not report the fitted model or the way participant-level dependence was handled in an outcome analysis.

Randomization can help reduce systematic differences in the order or assignment of conditions, depending on how it is implemented. However, the registry record does not state the randomization procedure or sequence. It does not report whether setting order was balanced, how time or period effects were assessed, or whether carryover was considered. These omissions do not show that such issues occurred; they mean that the registered information does not allow readers to assess how they were addressed.

How should uncertainty be evaluated?

A confidence interval is a general way to express uncertainty around an estimated effect. It gives a range of values compatible with the estimate under the specified statistical model and its assumptions. A narrower interval indicates greater precision than a wider interval, while an interval that includes values on either side of no difference may leave the direction or size of the effect uncertain. Confidence intervals for relevant comparisons are not reported in the registry record. There are also no posted p-values or outcome estimates from which to assess the statistical evidence.

Standard deviations and confidence intervals answer different questions. The standard deviation describes how much observed values vary, whereas a confidence interval concerns uncertainty about an estimated quantity. In repeated-measures data, the uncertainty of a within-participant contrast depends on the paired structure and correlation, not merely on separate standard deviations for each condition. The registry record gives no numerical dispersion or paired comparison results, so no estimate of precision can be interpreted.

Why does the timing of measurement matter?

Blood lactate is scheduled at rest and at multiple recovery times, from T2 through T60 as specified in the outcome description. A time course can distinguish an early response from a later one, but interpreting it statistically requires clarity about whether each time is analyzed separately, whether a trajectory is modeled, or whether a particular time or summary is the primary contrast. The record does not report that choice. It also does not state whether the change measure is calculated relative to rest, an exercise-test value, or another reference; the description says it starts from the exercise test and continues through recovery, but the exact computation is not reported.

Repeated measurements over time are usually correlated, just as measurements across therapy settings can be correlated within participants. General methods for correlated data can model this structure and estimate contrasts while accounting for dependence. The choice of model can affect uncertainty and interpretation. The registry record does not identify a covariance structure, modeling assumptions, or diagnostic checks, so a specific analytical approach cannot be attributed to the study.

What do the planning assumptions mean?

The record describes a sample-size planning illustration based on the observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. Such calculations are planning illustrations, not observed power and not results from the completed study. Their meaning depends on the assumed effect and design used for the calculation. The registry record describes a repeated-measures crossover study with four HVT settings, while the stated illustration uses equal allocation between two arms. No calculated planning values or observed effect estimates are reported in the registry record, so the illustration cannot establish the study's achieved precision.

In general, over-dispersion means that observed variability is greater than a model assumes. If it is ignored, standard errors may be too small and uncertainty may be understated. This is a general consideration rather than a reported finding for this study: the registry record does not report an outcome model or dispersion assessment. The same principle applies to within-participant correlation: analysis should reflect the data structure rather than assume independent measurements without justification.

In sum, the registry provides endpoint definitions, timing, summary measure, and design labels, but not inferential methods or results. The analysis model, contrast definitions, confidence intervals, missing-data procedures, and multiplicity handling are not reported in the registry record. Without them, the statistical strength and precision of any treatment-setting comparison cannot be evaluated.

10. Multiplicity, Missing Data and Analysis Populations

The study has a primary lactate outcome measured at rest and across multiple recovery times, along with secondary outcomes for respiratory rate, heart rate, SpO2, systolic blood pressure, diastolic blood pressure, and perceived exertion. The record also describes four HVT settings. These features create multiple possible comparisons. In general, when many outcomes, times, or contrasts are examined, the chance of a nominally notable result arising by chance can increase. A prespecified testing strategy or other multiplicity approach can help readers understand how the comparisons were prioritized. Such a strategy is not reported in the registry record.

The record does not identify a primary time point or a single overall contrast for the lactate outcome. It does not state whether the secondary outcomes are exploratory or confirmatory, or whether any adjustment for multiple testing was planned. Because no outcome analyses are posted, there are no results with which to assess how multiplicity affected interpretation.

Missing-data methods are also not reported in the registry record. The record does not state how unavailable measurements, withdrawals, protocol deviations, or incomplete recovery time courses were handled. It does not provide outcome-specific denominators or describe imputation, complete-case analysis, or sensitivity analyses. These are not claims that data were missing; they are details that are not reported.

The registry record does not define an intention-to-treat, per-protocol, or other analysis population for the outcomes. Enrollment of 15 and safety counts do not reveal which participants contributed to each efficacy analysis. Without analysis-population definitions, missing-data procedures, and a stated multiplicity plan, the statistical handling of the study's many measurements cannot be assessed from the registry record.

11. 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 record lists All Participants as the safety group, with 15 at risk for serious adverse events and 0 affected. For other adverse events, it lists 15 at risk and 0 affected. Deaths are listed as 0. The serious adverse event terms list is empty. These figures describe the recorded safety counts; they do not provide a comparison between therapy settings.

A zero count means that no event was recorded in the relevant category in this registry entry. It does not establish that the underlying risk is absent, nor does it show how precisely that risk is estimated. The record does not provide event definitions, the safety observation period, or details of how events were collected and attributed. It also does not explain how safety exposure was handled in the crossover structure. These details are not reported in the registry record.

The at-risk count is a safety denominator, not evidence that every participant completed every therapy setting or contributed to each outcome analysis. No adverse-event rates or comparisons should be inferred from the counts alone. The figures are best read narrowly as the registry's reported counts for serious events, other events, and deaths.

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

The registry record establishes that a completed randomized, unmasked crossover study was designed to evaluate High Velocity Therapy during a Wingate-type exercise test and recovery. It specifies blood lactate change as the primary outcome and describes measurements at rest and at multiple recovery times. It also lists secondary physiological and perceived-exertion outcomes. This information explains the study's intended question and measurement plan.

It does not establish the size or direction of any observed difference among the four HVT settings. The posted results do not report lactate estimates, secondary outcome estimates, confidence intervals, or statistical tests. As a result, the record cannot show whether responses differed, how variable they were, or how precisely any contrast was estimated. A completed status should not be mistaken for a reported efficacy analysis.

Nor can the record support a claim about the practical or clinical importance of a possible change. That judgment would require actual outcome estimates, their uncertainty, and a clear interpretation of the measurement scale and time course. The record does not give a threshold for meaningful change or report participant-level response patterns. The general purpose of measuring lactate during recovery does not substitute for these results.

The crossover design may support within-participant comparisons in principle, but the record does not describe setting order, washout, or the analysis model. It is therefore not possible to assess from the registry entry how period effects, carryover, or dependence among measurements were handled. Likewise, missing-data and analysis-population details are absent, and the multiplicity approach is not reported.

The defensible interpretation is therefore limited: the registry describes the design, outcomes, timing, and safety counts, but does not report the outcome analyses needed to assess effects. The zero adverse-event counts are descriptive and do not establish absence of risk. Further conclusions about comparative performance, precision, or safety are not reported in the registry record.

13. Why This Trial Matters Statistically

This study is statistically interesting because it combines a crossover design with repeated measurements over recovery and several therapy settings. The design raises familiar questions about within-participant correlation, setting order, and how to define a primary contrast. Those issues matter because the statistical analysis must correspond to the way measurements are collected. The registry record describes the repeated-measures structure but does not report the outcome model or how these design features were handled.

The endpoint is also a trajectory rather than a single scheduled observation: blood lactate is measured at rest and at multiple recovery times. An analysis can emphasize separate time-specific comparisons or an overall pattern across time, and those approaches answer different questions. A clear prespecified contrast helps distinguish the principal analysis from a search across times and settings. The registry record does not identify that contrast or state a multiplicity strategy.

These design features make transparent estimates and uncertainty particularly important. Means and standard deviations can describe distributions, but a crossover comparison also depends on paired differences and their variability. Confidence intervals and model details would help readers judge precision and the relevance of any estimated differences. Those outcome results are not reported in the registry record.

The record does offer useful boundaries for interpretation: the study is marked completed, the primary endpoint and secondary outcomes are named, and safety counts are listed. But design registration and outcome reporting serve different roles. Without posted analyses and explanations of missing data, analysis populations, and multiplicity, the registered plan cannot answer whether the settings differed or how reliably such differences were estimated.

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 contains limited detail about participant selection. It reports enrollment of 15 and lists conditions related to dyspnea, lactic acidosis, muscle, breathlessness, exercise, and recovery, but eligibility criteria and participant characteristics are not reported in the registry record. The enrollment count alone does not describe who participated or who contributed to each outcome analysis.

The intervention descriptions identify four flow and FiO2 combinations and state that participants were assessed in a repeated-measures model. Further operational details are not reported in the registry record, including the order of settings, washout procedures, and whether an untreated or other control condition was used. The randomization method is also not reported. Because masking is listed as none, participants and study personnel were not masked according to the registry entry; the record does not describe whether outcome assessment or analysis was otherwise blinded.

The primary outcome description gives the unit and measurement times, but does not fully define the change calculation or the exact statistical contrast. The analysis model, covariate handling, assumptions, and assessment of period or carryover effects are not reported in the registry record. Neither outcome estimates nor uncertainty measures are posted, and the analysis population and handling of incomplete measurements are not specified.

The study's multiple settings, time points, and secondary outcomes make the absence of a reported multiplicity plan important for interpretation. The record also does not report the rationale for the sample size or a protocol-level sample-size justification. The planning assumptions described in the record are illustrations based on the observed effect, not a substitute for a reported design justification or outcome analysis. These omissions limit assessment of precision, robustness, and the scope of conclusions that can be drawn.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effect of High Velocity/Hyperoxic Breathing Therapy on Blood Lactate Decline — NCT05984186.
• Registry record last updated 2024-10-08; status last verified 2024-09.
• Results first posted 2024-10-08.
• 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

The registry record identifies NCT05984186 as a completed, randomized, unmasked crossover study sponsored by Vapotherm, Inc. Enrollment is listed as 15. The study start date is 2023-03-06, and the primary completion date is 2023-07-31. The listed phase is NA.

The study evaluates High Velocity Therapy during a Wingate-type exercise test and recovery at four flow and FiO2 settings. Blood Lactate Change, measured in mmol/L at rest and across recovery, is the primary outcome. Secondary outcomes include respiratory rate, heart rate, SpO2, systolic and diastolic blood pressure, and perceived exertion change.

The registry lists 0 serious adverse events, 0 other adverse events, and 0 deaths, with 15 at risk for each adverse-event category. Outcome analyses and statistical comparisons are not reported in the registry record. The available record therefore describes the study design and measurement plan but does not provide results for judging differences among settings.