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 Evaluation Of The Total Face Mask For Emergency Application In Acute Respiratory Failure (NCT00686257), a randomized na study. The primary outcome is Mask Comfort (as Determined by the Visual Analog Scores 1 Being Least, 10 Being Most).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00686257 |
| Phase | NA |
| Condition | Acute Respiratory Insufficiency |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 60 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Tufts Medical Center |
| Results posted | Yes |
2. Clinical Question
Population
Patients with acute respiratory failure receiving noninvasive positive pressure ventilation (NPPV) in an emergency-treatment context. The registry record lists acute respiratory insufficiency as the condition. It does not provide additional eligibility criteria or a more detailed description of the enrolled population.
Intervention
NPPV delivered through the Total Face Mask, an interface covering the whole face. The intervention is the mask interface used to deliver ventilation, rather than a comparison of ventilation with no ventilation.
Comparator
NPPV delivered through a standard oronasal mask, covering the nose and mouth. The intervention descriptions identify Comfort full or RT040 oronasal masks as the comparator interface.
Primary question
During the first 3 hours of recruitment, how did patients’ comfort scores compare between the Total Face Mask and the standard oronasal mask? Comfort was assessed on a visual analog scale, with 1 defined as least comfort and 10 as most comfort. The posted outcome gives a mean score for each arm, but the registry record does not report a statistical test or confidence interval for the between-arm comparison.
The clinical question concerns the comfort of two interfaces while NPPV is being delivered. It is not a comparison of NPPV against another form of treatment, and the primary endpoint does not directly measure ventilation effectiveness, clinical deterioration, or recovery. The record also lists secondary outcomes involving discontinuation, vital signs, gas exchange, time requiring NPPV, hospital stay, and in-hospital mortality. Those outcomes address other aspects of treatment and clinical course, but their results are not included in the posted values.
3. Trial Design
The registry describes a randomized, parallel-group trial with no masking. Participants were assigned to receive NPPV using either the Total Face Mask or a standard oronasal mask. The parallel-group description means the record presents separate groups receiving the two interfaces; it does not describe a crossover design. Because masking is listed as none, the trial is recorded as open label. The registry does not report further details about random sequence generation, allocation concealment, or whether outcome assessment was conducted by someone unaware of assignment.
Enrollment is recorded as 60. The arm-level primary outcome summaries list 31 participants for the control arm and 29 for the Total Face Mask arm. The registry identifies the study phase as NA and its status as completed. The recorded start is 2003-01, and the primary completion date is 2008-06. Tufts Medical Center is identified as the sponsor. These administrative details describe the registered study; they do not supply information about the recruitment process, protocol changes, or reasons for the duration between the listed dates.
The study compares mask interfaces used for NPPV in emergency treatment of acute respiratory failure. The primary endpoint is comfort during the first 3 hours of recruitment. The registry lists six secondary outcomes: early NIV discontinuation, deterioration in vital signs, deterioration in gas exchange, total length of time requiring NIV, length of hospital stay, and in-hospital mortality. Although the record indicates eight outcome measures, it lists no analyses. A detailed statistical analysis plan, including the intended handling of repeated measurements or missing outcome data, is not reported in 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 | Total Face Mask | Standard Face Mask Controls |
|---|---|---|
| STARTED | 29 | 31 |
| COMPLETED | 29 | 31 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: By power analysis
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 | Total Face Mask | Standard Face Mask Controls | Total |
|---|---|---|---|---|
| Participants analysed | 29 | 31 | 60 | |
| Age, Continuous | years | 63.4 (SD 15) | 62.6 (SD 17) | 62.9 (SD 9) |
| Sex: Female, Male: Female | Participants | 14 | 17 | 31 |
| Sex: Female, Male: Male | Participants | 15 | 14 | 29 |
| Region of Enrollment: United States | participants | 29 | 31 | 60 |
6. Primary Endpoint
The registry lists the primary outcome as Mask Comfort (as Determined by the Visual Analog Scores 1 Being Least, 10 Being Most), measured over During the first 3 hours of recruitment.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Error |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is mask comfort, recorded as a visual analog score with 1 meaning least comfort and 10 meaning most comfort. The registry describes the outcome as a mean measured during the first 3 hours of recruitment. The reported arm-level means are 3.2 for the control arm and 3.3 for the Total Face Mask arm. Their corresponding standard errors are 0.6 and 0.7. These are summaries of the comfort scores, not descriptions of every participant’s experience.
Comfort is relevant to comparing interfaces because it captures a patient-reported aspect of wearing a mask during NPPV. In general, a visual analog scale turns a subjective assessment into a score that can be summarized across participants. A mean conveys the average score, while a measure of uncertainty such as the standard error describes how precisely that average is estimated. The score’s direction matters: higher values indicate greater comfort according to the registry’s scale definition.
The primary endpoint does not by itself establish whether one interface affects gas exchange, vital signs, treatment duration, or other clinical outcomes. Those topics appear among the secondary outcomes, but their posted results are not available in the registry record summarized for this comparison. The record also does not describe how the comfort scale was administered, whether scores were collected at more than one point within the stated timeframe, or how multiple measurements, if any, were combined.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary-outcome summaries are mean comfort scores of 3.2 in the control arm and 3.3 in the Total Face Mask arm. The reported standard errors are 0.6 and 0.7, respectively. On the stated scale, higher scores indicate more comfort. These arm-level values describe the observed summaries; they do not, on their own, establish that the interfaces differ in comfort or that any difference is statistically distinguishable from sampling variation.
The registry record does not report a p-value, confidence interval, or other inferential estimate for the between-arm contrast. It also records no analyses and gives a reason that values are missing or not estimable for a two-arm comparison of this continuous endpoint. Accordingly, the posted figures support a descriptive reading of each group’s mean and its standard error, but not a claim about the precision or statistical significance of the difference between groups. No contrast should be reconstructed from the arm-level values for this interpretation.
In general, a confidence interval for a between-group contrast would communicate a range of values compatible with the data and the method used to calculate it. A p-value would address how compatible the observed data are with a specified null hypothesis under a chosen model. Neither quantity is reported for this primary comparison, and neither can be inferred merely from the fact that arm means and standard errors are available. The registry record also does not state a threshold for a clinically important comfort difference.
The standard errors indicate uncertainty in the estimated arm means, not the spread of individual comfort scores. Without a reported comparison model or group-level distributions, the posted means and standard errors cannot show whether scores were concentrated near the means or varied substantially among participants. They also do not describe the frequency of very low or high scores.
The appropriate conclusion is therefore limited: the registry reports similar numerical arm-level mean scores, with the Total Face Mask arm’s reported mean at 3.3 and the control arm’s at 3.2. The record does not report an inferential comparison, so the numerical ordering should not be treated as evidence of a reliable or clinically meaningful difference. The secondary-outcome results are also not posted in the record, limiting interpretation beyond comfort.
9. Statistical Methods Explained
The primary outcome is continuous: it is a visual analog comfort score summarized using a mean. The registry reports a standard error alongside each mean. These summaries describe the average score and the precision of that average, but the record does not provide a reported estimate or test for the contrast between the randomized groups. It lists no analyses and states that values are missing or not estimable for a two-arm comparison of the continuous endpoint. The statistical interpretation must therefore remain descriptive.
What does a mean summarize?
In general, a mean is the arithmetic average of the observed scores in a group. It is useful for describing the central level of a continuous measure, but it does not reveal the full score distribution. Different groups can have the same mean while differing in variability, skewness, or the frequency of unusually low or high observations. No distributional summaries beyond the means and standard errors are reported for this endpoint.
What does the standard error describe?
In general, the standard error describes the sampling uncertainty of an estimated quantity, such as a group mean. It is not the standard deviation of individual scores and should not be read as a measure of how much participants’ experiences varied. The reported standard errors are 0.6 for the control mean and 0.7 for the Total Face Mask mean. The record does not state the calculation details or provide the individual-level scores needed to assess the distribution directly.
Why is the between-group estimate important?
A comparison of randomized groups is ordinarily expressed as a contrast, such as a difference between means, with uncertainty around that contrast. In general, the contrast addresses the study’s comparative question more directly than separate within-group summaries. Uncertainty for the contrast depends on the data and the analysis method, including assumptions about the relationship between observations and how missing values are handled. The registry record does not report a contrast, its standard error, a confidence interval, or a hypothesis test. No recalculated comparison is reported for this endpoint.
What can a confidence interval tell a reader?
In general, a confidence interval gives an uncertainty range for an estimate under a stated statistical procedure and its assumptions. For a between-group contrast, it helps show which magnitudes of difference are compatible with the observed data and the method used. It is not a guarantee that the true effect lies within a particular interval. Since the registry record does not give a confidence interval for the comfort comparison, the precision of the contrast cannot be evaluated from a reported interval.
How should a p-value be understood?
In general, a p-value measures how unusual data at least as incompatible with a specified null hypothesis would be under the statistical model used, assuming that null hypothesis. It does not give the probability that the null hypothesis is true, and it does not measure the clinical importance of an effect. No p-value or test result for the primary comparison is reported in the registry record. The arm means alone cannot be used to claim statistical significance.
What do the planning calculations represent?
Any sample-size figures associated with the posted results are planning illustrations based on the observed effect, not the trial’s own design calculations and not observed power. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. Such calculations describe hypothetical planning under those assumptions. They do not show that the study had a particular probability of detecting an effect, and they cannot replace the trial’s analysis. The registry record does not report its own sample-size justification or the assumptions used to plan enrollment.
More generally, interpretation of a continuous outcome also depends on the scale’s measurement properties and the appropriateness of the chosen summary. The registry defines the direction of the comfort scale but does not report details about its administration, validation, or the analysis model. Since the primary endpoint is reported as a mean with a standard error, a reader can describe those posted summaries but should not infer unreported model choices, adjusted results, or a clinically important threshold.
10. Confidence Intervals for Each Arm
No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.
| Arm | Participants | Mean | Standard deviation | 95% CI for the mean |
|---|---|---|---|---|
| Control | 31 | 3.200 | 3.341 | 1.975 to 4.425 |
R code and output
arm <- c("Control")
n <- c(31)
m <- c(3.2)
sp <- c(0.6)
sd <- sp * sqrt(n) # standard errors converted to SDs
for (i in seq_along(n)) {
se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}
CARM Control 31 3.200 3.341 1.975 4.42511. Multiplicity, Missing Data and Analysis Populations
The registry lists eight outcome measures and identifies six secondary outcomes: early NIV discontinuation, deterioration in vital signs, deterioration in gas exchange, total length of time requiring NIV, length of hospital stay, and in-hospital mortality. It does not report analyses for these outcomes in the record. The primary comfort outcome has arm-level descriptive summaries, but the record does not report an inferential comparison.
When a study assesses multiple outcomes, multiplicity can matter because repeated testing can increase the chance of obtaining at least one apparently notable result by chance. In general, a prespecified hierarchy, adjustment method, or clear distinction between primary and exploratory outcomes helps readers understand how multiple comparisons were handled. The registry record does not report a multiplicity strategy, a detailed statistical plan, or whether any outcomes were designated for formal hypothesis testing beyond identifying the primary outcome.
Missing-data methods and analysis populations are also not reported in the registry record. The primary-outcome summaries include 31 participants in the control arm and 29 in the Total Face Mask arm, but the record does not state whether these counts represent everyone randomized, everyone with a measured comfort score, or another analysis population. It does not describe the amount or reasons for missing comfort measurements, any imputation approach, or sensitivity analyses.
These omissions limit assessment of how robust the results are to missing observations and how the analysis relates to randomized assignment. The record does not report an intention-to-treat definition or a per-protocol population. Such details should not be inferred from the posted arm summaries or the randomized design label.
12. 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 |
|---|---|---|---|
| Total Face Mask | 0 | 29 | 0.0% |
| Standard Face Mask Controls | 0 | 31 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 4% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Total Face Mask | 6 of 29 |
| Standard Face Mask Controls | 4 of 31 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Total Face Mask | Standard Face Mask Controls |
|---|---|---|---|
| Claustrophobia | Respiratory, thoracic and mediastinal disorders | 6 of 29 | 4 of 31 |
The registry reports zero serious adverse events among 29 participants at risk in the Total Face Mask group and zero among 31 at risk in the standard face mask control group. It lists no serious adverse-event terms. These figures describe what is recorded for the listed at-risk groups; they do not establish that serious events were impossible or that every possible event was captured.
For other adverse events, the record reports 6 affected participants among 29 at risk in the Total Face Mask group and 4 among 31 at risk in the standard face mask control group. These counts are presented in the registry’s other-adverse-event category and should not be conflated with the serious-event counts. The record does not provide event-specific descriptions for these other adverse events, so their nature and severity cannot be characterized from the counts alone.
Deaths are listed as null for both groups, which means the death values are not reported in the registry record; null should not be interpreted as a reported count of zero. The record does not provide further information about adverse-event definitions, monitoring procedures, attribution, or the observation period. These safety counts are descriptive and do not constitute a comparative statistical analysis.
13. What the Result Does, and Does Not, Mean
The registered comparison asks whether comfort scores differed between patients using the Total Face Mask and those using a standard oronasal mask during NPPV. The posted primary endpoint consists of a mean and standard error for each arm. The Total Face Mask arm’s mean is 3.3, and the control arm’s mean is 3.2, on a scale where higher values indicate more comfort. The registry does not report a formal between-arm estimate, confidence interval, or p-value.
These figures therefore describe the recorded group summaries without resolving how much uncertainty surrounds the comparative result. The arm-level standard errors are not a substitute for uncertainty around the contrast, and they do not describe the range of individual scores. With no reported analysis of the contrast, the numerical ordering of the means should not be interpreted as proof of superiority, equivalence, or absence of a difference.
The record also does not report the results of the listed secondary outcomes. As a result, the posted primary outcome cannot answer whether the mask interfaces differed in early discontinuation, vital-sign deterioration, gas-exchange deterioration, time requiring NIV, hospital stay, or in-hospital mortality. Nor does a comfort score alone establish an effect on clinical course.
In general, statistical evidence and clinical importance are distinct questions. A small estimated difference can be precise but not important to patients, while a potentially important difference can be estimated imprecisely. The registry record does not report a threshold for a clinically important comfort difference or an inferential result that would allow those questions to be assessed. The record supports a narrow descriptive statement about the posted means and adverse-event counts, not a broader conclusion about which interface is preferable or about treatment effectiveness.
14. Why This Trial Matters Statistically
This trial illustrates the difference between reporting group summaries and reporting a comparative analysis. The randomized design sets up a comparison between two mask interfaces, but the registry record presents only the primary outcome’s arm-level means and standard errors. Without a reported contrast and its uncertainty, a reader cannot directly judge the precision of the comparative result. The study is therefore a useful example of why a result’s statistical interpretation depends not only on the values observed in each group but also on how the between-group question is analyzed and reported.
The endpoint also highlights the distinction between a patient-reported measure and clinical outcomes. Comfort can capture an experience that is not represented by physiological measures, while the listed secondary outcomes concern discontinuation, deterioration, treatment duration, hospital stay, and mortality. A complete interpretation would require results for those outcomes as well as an understanding of their analysis. Those results are not reported in the registry record.
Reporting standard errors alongside means helps distinguish uncertainty in an average from variation among individuals, but the distinction is easy to miss. The record does not provide individual-level distributions or a confidence interval for the comparison. Nor does it document missing-data handling, analysis populations, or a multiplicity approach. These gaps matter for assessing how much confidence to place in the posted summaries and how completely the analysis answers the registered question.
The planning illustrations offer another useful statistical distinction: calculations based on an observed effect are planning scenarios, not evidence that the trial had a certain probability of detecting an effect. They should not be confused with an observed power calculation or with the study’s unreported original design justification. Together, these features make the record an example of the value of transparent statistical reporting alongside trial design information.
15. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The main limitation for interpreting the primary outcome is that the registry does not report a two-arm inferential comparison for the continuous comfort score. Although means and standard errors are posted for both arms, no contrast, confidence interval, or p-value is reported. The record explicitly indicates that values are missing or not estimable for a two-arm comparison of this endpoint, so interpretation should remain descriptive.
The registry also does not describe how the comfort score was collected beyond its visual analog scale definition and the timeframe of the first 3 hours of recruitment. Details such as administration procedures, score timing within that timeframe, and whether repeated measurements were combined are not reported. The record does not state a clinically important difference threshold, limiting interpretation of the practical meaning of the arm-level means.
Although the study is recorded as randomized and unmasked, further design and analysis details are not reported. The registry record does not explain sequence generation or allocation concealment, identify analysis populations, or describe handling of missing outcome data. It lists secondary outcomes but does not report their results or the analysis strategy for them. No multiplicity plan or detailed statistical analysis plan is reported.
The adverse-event record is similarly limited: serious-event counts and other-adverse-event counts are reported, but event-specific details and the safety observation procedures are not. Death values are not reported in the registry record. These limitations prevent a fuller assessment of outcome completeness, comparative uncertainty, and the broader clinical course from the registry information alone.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Evaluation Of The Total Face Mask For Emergency Application In Acute Respiratory Failure — NCT00686257.
- Registry record last updated 2018-06-25; status last verified 2018-05.
- Results first posted 2012-08-27.
- 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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19. Record Summary
NCT00686257 is a completed, randomized, unmasked, parallel-group study sponsored by Tufts Medical Center. It compared NPPV delivered through a Total Face Mask with NPPV delivered through a standard oronasal mask for emergency treatment of acute respiratory failure. Enrollment is recorded as 60; the listed start is 2003-01 and primary completion is 2008-06.
The primary outcome was mean comfort on a visual analog scale, where 1 indicates least comfort and 10 indicates most comfort, during the first 3 hours of recruitment. The posted means are 3.2 for control and 3.3 for the Total Face Mask, with standard errors of 0.6 and 0.7. No inferential comparison is reported. The registry also lists six secondary outcomes but no analyses. It reports zero serious adverse events in each group, other adverse events affecting 6 of 29 and 4 of 31 at risk, and deaths as not reported.