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 Bidirectional Oxygenation Valve in the Management of Pulmonary Complications of COVID-19 (NCT04331366), a na na study. The primary outcome is Oxygen Saturation by Pulse Oximetry.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04331366 |
| Phase | NA |
| Condition | COVID-19 |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 2 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Emory University |
| Results posted | Yes |
2. Clinical Question
Population
People with COVID-19 who required supplemental oxygen by non-rebreather mask. The registry record reports enrollment of 2 participants. Further eligibility criteria and participant characteristics are not reported in the registry record.
Intervention
Treatment with the GO2 PEEP MOUTHPIECE, described as a bidirectional oxygenation Positive End Expiratory Pressure (PEEP) mouthpiece. The record’s stated objective is to assess its safety, feasibility and efficacy in this clinical setting. Details about how the device was used beyond this description are not reported in the registry record.
Comparator
There is no control group listed. The study is identified as single-group, with allocation recorded as NA, so the record does not describe a randomized or like-for-like comparison between treatment arms.
Primary question
How did mean oxygen saturation measured by pulse oximetry change across the stated measurement times during and after treatment with the mouthpiece? The registry record names oxygen saturation as the primary outcome but reports no numerical results or analysis of change.
The question is descriptive in this design: the record concerns observations in participants receiving the device, rather than a comparison against a separate control group. Without a control group, any observed change could not, on its own, distinguish an effect of the mouthpiece from other explanations. The registry record does not report the participants’ oxygen saturation values, their variability, or an estimate of change. It therefore does not establish the direction or size of any change in the primary outcome.
3. Trial Design
The registry record identifies this as a completed, single-group study of the GO2 PEEP MOUTHPIECE, a device intervention. Enrollment was 2. The study’s brief summary describes the intended population as people with COVID-19 requiring supplemental oxygen by non-rebreather mask. The listed condition is COVID-19. More detailed eligibility criteria and baseline participant characteristics are not reported in the registry record.
Allocation is recorded as NA, and the study model is single group. Masking is recorded as none. The record lists treatment with the GO2 PEEP MOUTHPIECE and does not list a separate control arm. This design can describe what was observed in participants receiving the device, but it does not provide a randomized comparison with another treatment or usual care. Consequently, a treatment-versus-control effect cannot be estimated from the design as registered.
The primary outcome is mean oxygen saturation by pulse oximetry, expressed as a percentage of oxygen saturation with standard deviation as the stated measure of dispersion. Measurements were scheduled at baseline and Minutes 5, 10, 15, and 30, with the last timing described as 15 minutes after treatment ends. The record also lists respiratory rate, heart rate, blood pressure, and count of participants with subjective work of breathing as secondary outcomes. It reports five outcome measures in total, but the details of any additional measure are not reported in the registry record.
The study status is completed. Its start date is 2020-04-08, and its primary completion date is 2020-08-31. The registry record does not report a protocol rationale for the sample size, the intended analysis methods, or whether interim analyses were planned. It records zero analyses and contains no numerical outcome results. Therefore, the design and measurement schedule can be described, but outcome estimates and their precision cannot be assessed from the registry 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
| Stage | GO2 PEEP MOUTHPIECE |
|---|---|
| STARTED | 2 |
| COMPLETED | 2 |
| NOT COMPLETED | 0 |
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.
| Characteristic | Unit | GO2 PEEP MOUTHPIECE |
|---|---|---|
| Participants analysed | 2 | |
| Age, Continuous | years | 60.71 (SD 21.25) |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 2 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 1 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 1 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 |
| Race (NIH/OMB): White | Participants | 1 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 1 |
| Region of Enrollment: United States | Participants | 2 |
6. Primary Endpoint
The registry lists the primary outcome as Oxygen Saturation by Pulse Oximetry, measured over Baseline, Minutes 5, 10, 15, 30 (15 minutes after treatment ends).
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | percentage of oxygen saturation |
| Endpoint classification | Continuous Endpoint |
The primary outcome is oxygen saturation measured by pulse oximetry, with the result expressed as a percentage of oxygen saturation. Pulse oximetry is a non-invasive way to assess oxygen saturation. The registry record states that it is used to assess whether a patient needs help breathing, and notes that oxygen saturation levels for healthy individuals are 95% and above. That contextual statement is not a result from this study and does not define a treatment target or a study success threshold.
The outcome is specified as a mean, with standard deviation used to describe dispersion. A mean represents the average of measured values; a standard deviation describes how spread out individual measurements are around that average. These summaries can describe the group’s observed oxygen saturation at a given time, but they do not by themselves show how values changed within participants or establish why a change occurred.
Measurements were scheduled at baseline, Minutes 5, 10, 15, and 30. The record describes the final measurement as 15 minutes after treatment ends. This repeated schedule is intended to capture oxygen saturation at several points during and after treatment. However, the registry record reports no values at any time point, no standard deviations, and no estimate of change from baseline. It also does not report how many observations were available at each time.
Without those outcome data, neither the observed oxygen saturation levels nor their variability can be evaluated. The stated outcome definition and schedule describe what was intended to be measured, not what was found.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record reports a completed study with enrollment of 2, but it does not provide numerical results for the primary outcome. There are no posted mean oxygen saturation values, standard deviations, or estimates of change at baseline, Minutes 5, 10, 15, or 30. The record also reports zero analyses. As a result, there is no reported primary-outcome estimate to interpret and no basis in the registry record for describing the direction, size, or precision of an oxygen-saturation change.
The study is single group, with allocation recorded as NA and masking recorded as none. No control group is listed. Even if before-and-after measurements were available, a change over time in a single group would not by itself isolate an effect of the device. Other events over the same period could also be associated with changes. The registry record does not provide comparative data that would address this limitation.
The outcome is described as a mean with standard deviation. A standard deviation would describe variability among observed measurements, but it is not a confidence interval and does not quantify the precision of an estimated mean or change. No confidence interval, standard error, hypothesis test, or other inferential result is reported in the registry record. There is therefore no reported uncertainty interval from which to assess how compatible the data might be with different possible values.
The record lists secondary outcomes of respiratory rate, heart rate, blood pressure, and count of participants with subjective work of breathing. It does not report numerical findings or analyses for these outcomes either. Five outcome measures are reported in total, but the details of the remaining measure are not reported in the registry record. A list of intended outcomes is not evidence that an outcome changed in a particular direction.
The enrollment of 2 means the record concerns very few participants. In general, estimates based on very small groups are sensitive to the observations of individual participants and provide limited information about variability across a broader population. Here, because no outcome values are reported, it is not possible even to describe the observed values within this small group. The record’s completion status does not fill that reporting gap.
The safety figures are also limited in scope: the registry records zero participants with a serious adverse event among 2 at risk, one participant with another adverse event among 2 at risk, and zero deaths. These are descriptive counts for this study, not estimates that establish the frequency of events in a broader population. The serious-event terminology list is empty. The registry record does not provide event descriptions or additional context for the other adverse event.
Overall, the registry record documents the study question, single-group design, outcome schedule, and a small enrollment. It does not report outcome analyses that would support a quantitative conclusion about oxygen saturation, secondary outcomes, or comparative effects. The absence of posted results should not be mistaken for a finding of no change or no effect.
9. Statistical Methods Explained
The registry record describes a single-group study and identifies mean oxygen saturation as the primary measure. No analyses are reported. The following concepts explain what the stated outcome summaries and common analysis approaches mean in general; they are not descriptions of analyses documented for this study.
What does a mean describe?
For a continuous measure such as oxygen saturation, the mean is the arithmetic average of observed values. It gives a compact description of a group at a particular measurement time. It does not show whether all participants had similar values or whether some observations were far from the average. The registry record specifies mean oxygen saturation and standard deviation, but does not publish either statistic for any scheduled time.
What does standard deviation describe?
In general, standard deviation describes dispersion among observations around their mean. A larger standard deviation indicates more spread in the observed values; a smaller one indicates values are more tightly clustered. It is a description of variability in the data, not a measure of uncertainty in the mean itself. A confidence interval, by contrast, is an inferential range constructed to express uncertainty about an estimated quantity under a specified statistical method. The registry record reports no standard deviations or confidence intervals.
How would repeated measurements be interpreted?
The primary outcome schedule includes baseline and several post-baseline times, including a final measurement described as 15 minutes after treatment ends. Repeated observations from the same person are related: they are not equivalent to observations from unrelated people. In general, an analysis of repeated measurements should account for that within-person dependence when estimating change or comparing time points. A simple comparison that treats all measurements as independent could misstate uncertainty. The registry record does not identify an analysis method for repeated measurements, report participant-level data, or provide estimates at the scheduled times.
What can a single-group design estimate?
A single-group study can describe measurements observed among participants who received the intervention. If measurements before and after treatment are available, an analysis could estimate within-group change. Such a change is not automatically a causal treatment effect. Without a concurrent comparator, changes associated with time, co-interventions, measurement circumstances, or other influences cannot be separated from the intervention’s contribution using the design alone. The registry record does not report a control group or a comparative effect estimate.
What does a confidence interval add?
In general, a confidence interval communicates uncertainty around an estimate, using a method that depends on the design and assumptions. Narrower intervals indicate greater precision under those assumptions; wider intervals indicate less precision. An interval does not repair a design limitation such as the absence of a control group, and it does not establish that a result is free from bias. No estimate or interval is reported for this study, so its statistical precision cannot be assessed from the registry record.
What is over-dispersion?
In general, over-dispersion arises when the observed variability in data is greater than a statistical model assumes. If a model underestimates variability, standard errors may be too small and inferential intervals or tests may appear more certain than warranted. This concept is relevant to some outcome types and models, but the registry record does not report a model, a dispersion assessment, or analyses that would establish whether over-dispersion was relevant to this study.
What do the planning assumptions mean?
The record describes a sample-size planning illustration based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the planned effect is a stated fraction of the observed effect. These are planning assumptions, not the trial’s reported analysis plan. The registry record does not report the trial’s own sample-size justification. The stated equal-allocation, two-arm assumptions do not describe the registered single-group design. Any resulting sample-size figures are planning illustrations, not observed power, and they do not supply missing outcome results or establish that the study was adequately sized.
The record does not report a statistical analysis plan, hypothesis tests, adjustment methods, or confidence intervals. It also does not report whether any analyses were planned or conducted beyond recording zero analyses. Consequently, statistical methods beyond the outcome’s mean-and-standard-deviation description cannot be attributed to the study.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists oxygen saturation as the primary outcome and names respiratory rate, heart rate, blood pressure, and count of participants with subjective work of breathing as secondary outcomes. It also reports five outcome measures overall, without identifying the details of an additional measure. Because several outcomes and time points are listed, a complete analysis plan would ordinarily clarify which comparisons are central and how multiple statistical tests are handled. Such a plan is not reported in the registry record.
Multiplicity arises in general when several hypotheses or comparisons are examined. Without a stated approach, repeated testing can increase the chance of at least one apparently notable finding arising by chance. This is a general statistical concern, not a claim that such testing occurred in this study. The registry record reports zero analyses, so there are no reported tests or adjusted results to evaluate.
The record does not describe missing-data handling, the number of observations available at each time point, or whether every enrolled participant contributed each outcome. It does not report analysis populations, such as whether analyses included all enrolled participants or only participants with observed measurements. These details are not reported in the registry record. With only 2 participants enrolled and no outcome values, the extent or consequences of missing data cannot be assessed.
The record also does not report a prespecified statistical analysis plan, interim analyses, or methods for handling repeated measurements. Their absence from the registry record should be read as missing documentation, not evidence that a particular method was or was not used outside the record.
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 |
|---|---|---|---|
| GO2 PEEP MOUTHPIECE | 0 | 2 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| GO2 PEEP MOUTHPIECE | 0 of 2 |
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 |
|---|---|
| GO2 PEEP MOUTHPIECE | 1 of 2 |
Most frequent non-serious adverse event terms
| Event term | Organ system | GO2 PEEP MOUTHPIECE |
|---|---|---|
| Decrease in oxygen saturation after cessation of PEEP therapy | Respiratory, thoracic and mediastinal disorders | 1 of 2 |
The registry record lists the GO2 PEEP MOUTHPIECE group with 2 participants at risk for serious adverse events and 0 participants affected. It lists 2 participants at risk for other adverse events and 1 affected. Deaths are reported as 0. No serious adverse event terms are listed.
These are counts recorded for the small enrolled group. The serious adverse event count means that no participant is recorded as affected by a serious adverse event in this registry entry; it does not establish that serious events could not occur or precisely characterize risk beyond this group. Likewise, the count for other adverse events is not accompanied by event descriptions in the registry record, so the nature, timing, severity, and relationship to the device are not reported. The figures should be read as descriptive registry counts, not as comparative safety estimates. No control group is listed, and the record does not report a statistical safety analysis.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a completed, single-group study enrolled 2 participants and planned to measure oxygen saturation at baseline and several times during and after treatment with the GO2 PEEP MOUTHPIECE. It also lists secondary outcomes and adverse-event counts. Those details describe the study’s scope and what the registry reports; they do not show whether oxygen saturation or another outcome changed.
No numerical primary-outcome results or analyses are reported. There is no reported mean, standard deviation, change estimate, confidence interval, or hypothesis test. Therefore, the record cannot support a quantitative statement about the direction, size, or precision of any change in oxygen saturation. The absence of results is not evidence that there was no change.
The single-group design also limits what could be concluded even if within-group changes were available. Without a control group, an observed change would not by itself establish that the device caused it. The registry record does not report comparative evidence, and the unmasked design does not provide masking as a safeguard against influences on measurement or assessment.
The safety counts are similarly descriptive. The record lists zero participants with serious adverse events, one participant with another adverse event, and zero deaths. These counts do not establish a general rate of events or allow comparison with another treatment. The record does not describe the other adverse event, and the serious adverse event terms list is empty.
The study’s stated objective includes safety, feasibility, and efficacy, but the registry record does not report numerical findings for these aims. Its completion status indicates the study is recorded as completed; it does not substitute for outcome reporting. The evidence available in the record is therefore insufficient to judge the measured outcomes or to draw a comparative conclusion.
13. Why This Trial Matters Statistically
This study is statistically notable for the gap between a clearly stated measurement question and the absence of posted outcome analyses. The registry specifies oxygen saturation as the primary outcome, identifies the summary measure as a mean with standard deviation, and gives a schedule spanning baseline and post-treatment measurements. Yet it reports no numerical values or analyses. Readers can identify what was intended to be measured, but cannot evaluate what was observed.
The design also illustrates the distinction between describing a group and estimating a comparative effect. A single-group study can document observations among participants receiving an intervention. It does not, by itself, provide a concurrent counterfactual showing what would have happened to comparable participants without that intervention. This distinction is important when interpreting any before-and-after data, and especially when the registry record does not report the values at all.
The small enrollment of 2 participants makes transparent reporting of individual observations particularly important in general: each participant’s data can meaningfully shape a group summary. The registry record does not report participant-level results, group summaries, or uncertainty estimates. That prevents evaluation of both the pattern of measurements and their variability.
The record also names multiple outcomes and measurement times without reporting a statistical analysis plan or multiplicity approach. This does not establish that inappropriate analyses occurred; it means the registry entry does not permit readers to assess how multiple outcomes and repeated measurements were to be interpreted. Overall, the entry is useful for identifying the design and intended endpoints, while illustrating why outcome reporting and clearly documented analysis methods are necessary for statistical interpretation.
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.
Several limitations are specific to the information recorded for this study. Enrollment was 2, and the registry record provides no participant characteristics or detailed eligibility criteria beyond the description of people with COVID-19 requiring supplemental oxygen by non-rebreather mask. The characteristics of the enrolled group and the extent to which it represents the intended population are therefore not reported.
The study is single group, with no control arm listed, allocation recorded as NA, and masking recorded as none. This design does not provide a randomized comparison. Any within-person or over-time pattern, if results were available, would need to be interpreted without a concurrent control to distinguish intervention-associated change from other influences. No results are reported in any case.
The record specifies a repeated-measurement schedule but does not report observed values, standard deviations, participant-level measurements, or the number of observations available at each time. It does not describe the statistical methods used to account for repeated observations. It also does not report a statistical analysis plan, missing-data methods, analysis populations, or interim analyses. These omissions prevent assessment of the analysis approach and the completeness of outcome reporting.
Although the study is marked completed, the record reports zero analyses and no numerical outcome results. The record’s adverse-event counts are limited to descriptive totals; event descriptions for the other adverse event are not reported, and no serious adverse event terms are listed. These limitations constrain interpretation of both the intended efficacy and safety questions.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Bidirectional Oxygenation Valve in the Management of Pulmonary Complications of COVID-19 — NCT04331366.
- Registry record last updated 2021-02-18; status last verified 2021-02.
- Results first posted 2021-02-10.
- 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
The registry record describes the GO2 PEEP Study as a completed, single-group device study in people with COVID-19 requiring supplemental oxygen by non-rebreather mask. Enrollment was 2. The intervention was the GO2 PEEP MOUTHPIECE. Allocation is recorded as NA, and masking as none.
The primary outcome was mean oxygen saturation by pulse oximetry, with standard deviation specified as the measure of dispersion. Measurements were scheduled at baseline and Minutes 5, 10, 15, and 30, with the final measurement described as 15 minutes after treatment ends. Secondary outcomes include respiratory rate, heart rate, blood pressure, and count of participants with subjective work of breathing.
The registry record reports zero analyses and no numerical outcome results. It records zero serious adverse events among 2 at risk, one participant with another adverse event among 2 at risk, and zero deaths. The study’s start date was 2020-04-08, and its primary completion date was 2020-08-31.