Does Endurance Improve With the Use of Passy-Muir Valve for Patients With Tracheostomy?: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Does Endurance Improve With the Use of Passy-Muir Valve for Patients With Tracheostomy? (NCT04941456), a non-randomized na study. The primary outcome is Six Minute Walk Test - First Paired Sessions.

2. Clinical Question

The study focuses on ambulation distance as a measure of exercise endurance. Each test asks a participant to walk as far as possible along a corridor for six minutes. A balance device and investigator assistance may be used as needed, so the measurement reflects performance under the study's described testing conditions rather than an unsupported or unaided walk.

The comparison is within a crossover design: participants are assessed under both conditions, with the order varying between the two described sequences. This permits comparison of the same participant's performance across conditions, but the record labels allocation as non-randomized. It therefore should not be read as a randomized, like-for-like control comparison. Whether the sequence or timing affected the comparison is not reported in the registry record.

The primary outcome is identified as the six-minute walk test during the first paired sessions. The stated timing places the initial session within 72 hours after clearance for valve use, with the paired session scheduled the day after the first. The registry record does not report a result for this primary question.

3. Trial Design

This is a completed, non-randomized crossover study of Passy-Muir Valve use compared with an open tracheostomy. The record lists an enrollment of 26 and describes two sequences. In one, participants use an open tracheostomy on day 1 and switch to a Passy-Muir Valve on day 2. In the other, the valve is used first and the open-tracheostomy condition follows. The sequences are described as alternating between conditions over study sessions.

The primary outcome is the six-minute walk test in the first paired sessions. The record describes the first session as occurring within 72 hours after medical staff clear a participant for valve use, and the second paired session as occurring the next day. The broader outcome description refers to alternating sessions on consecutive weekdays, with three sessions under each condition and a minimum of 2 to maximum of 6 sessions. It also describes this as 1 to 3 completed paired sessions. The record does not clarify how these scheduling descriptions relate to the primary first-pair analysis for participants with different numbers of completed sessions.

Although participants encounter both conditions, this is not a randomized allocation. The registry record explicitly cautions that the arms are not a like-for-like control comparison. The order of conditions could matter in a crossover study, for example if performance changes with practice, fatigue, recovery, or time. These are general considerations; whether they affected this study is not reported in the registry record.

The record identifies the study as completed and gives the study start as 2021-07-29 and primary completion as 2024-06-24. The phase is listed as not applicable. It names Gaylord Hospital, Inc as sponsor. Details on concealment of sequence, eligibility criteria beyond the clearance description, analysis methods, and the reasons for choosing the enrollment target are 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.

Before assignment: Patients were excluded from study inclusion if they did not meet one or more study criteria.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Ambulation distance (feet)

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 Six Minute Walk Test - First Paired Sessions, measured over The first paired study session (Day 1) will occur within 72 hours of the participant being cleared by Medical Staff for PMV use. The second paired session will occur the day after session 1 (Day 2)..

The primary endpoint is the distance walked, in feet, during a six-minute walk test in the first paired study sessions. Participants are asked to walk as far as possible along a corridor during the test period. The outcome is recorded as a mean with standard deviation, according to the registry record's measure description. The posted results do not give the observed means or standard deviations.

As a general statistical concept, the six-minute walk test turns a period of walking into a continuous measure of functional exercise performance. Distance is useful for comparing conditions because it retains information about how far each participant walked, rather than reducing performance to a yes-or-no outcome. The distance can vary between participants, which is one reason a summary of the mean is often accompanied by a measure of dispersion such as the standard deviation.

The crossover format makes the paired comparison important: the primary question concerns distance under each condition for participants tested in both. A within-participant comparison can account for stable differences between people, but it does not by itself resolve changes associated with order or time. The registry record does not report the statistical model or the method used to handle pairing, order, or participants who did not complete both sessions.

The endpoint's description allows a balance device and investigator assistance if needed. Thus the recorded distance reflects the test as conducted, including such assistance where applicable. The record does not report how often aids or assistance were used, how test interruptions were handled, or whether any alternative endpoint was used when a participant could not complete a test.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean describe?

The primary measure is a continuous distance in feet, summarized in the record as a mean. In general, a mean represents the arithmetic center of the observed measurements. It is a compact description of performance, but it does not show how evenly measurements are distributed or whether some participants' results are far from the center. The mean values for either condition are not reported in the registry record, so there is no observed average to interpret.

What does the standard deviation describe?

The endpoint description specifies standard deviation as the measure of dispersion. In general, standard deviation describes how spread out measurements are around their mean. A larger spread means greater variation among recorded distances, while a smaller spread means the observations are more closely grouped. It is not the same as the uncertainty in a treatment contrast or the precision of the mean. The standard deviations are not reported in the registry record.

Why does pairing matter?

In a crossover study, the same participant is assessed under both conditions. As a general statistical principle, the relationship between a participant's measurements across conditions can carry information: a paired analysis focuses on within-participant changes rather than treating all measurements as unrelated. This can be appropriate when measurements are genuinely paired and the analysis respects that structure. The registry record does not state whether the primary analysis used paired differences, a repeated-measures model, or another method. It also does not report how incomplete pairs were handled.

Pairing does not make order irrelevant. The record describes sequences beginning with either open tracheostomy or valve use, and sessions on successive days. General crossover considerations include practice, fatigue, changes in clinical status, and other time-related influences. If such influences differ across sequence or session, they could affect a condition contrast. The record does not report an analysis of sequence, period, carryover, or time effects, nor does it give enough outcome data to evaluate them independently.

What does non-randomized allocation imply?

Allocation is listed as non-randomized, and the record cautions that the arms are not a like-for-like control comparison. In general, random assignment is one way to reduce systematic differences in treatment assignment. In a non-randomized study, the order or condition may be related to other characteristics or circumstances. Within-participant measurement can address some stable differences between participants, but it does not automatically remove confounding from changing conditions or sequence. The record does not explain how the order was assigned or whether any adjustment was planned.

How should confidence intervals and p-values be read?

In general, a confidence interval conveys uncertainty around an estimated effect under the assumptions of the analysis. A narrow interval indicates greater statistical precision than a wide interval, though the interval alone does not establish clinical importance. A p-value summarizes how unusual the data would be under a specified null hypothesis and model; it is not the probability that the null hypothesis is true. Neither an interval nor a p-value for the primary comparison is reported in the registry record. It is therefore not possible to describe statistical significance or precision from the posted results.

What can sample-size planning illustrations say?

The registry record describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. These are planning assumptions, not a description of the trial's original design justification. The record does not report the study's own sample-size justification. Any planning illustration is not observed power and should not be read as evidence that the study was adequately powered or that a particular effect was detected. The actual planning counts are not reported in the registry record details available for this explanation.

More generally, power calculations depend on assumptions about the target effect, variability, significance level, allocation, and analysis. Changing those assumptions changes the planning result. A calculation anchored to an observed effect is especially not a substitute for a prespecified design calculation: the observed effect itself may be uncertain. No inference about the trial's operating characteristics should be made without its design assumptions and analysis details.

Which analysis was used?

The registry record identifies the primary measure as a mean of a continuous outcome, but does not report the statistical plan, model, handling of repeated sessions, adjustment variables, or the exact analysis population. It also does not state whether interim analyses were planned or conducted. These omissions prevent a detailed appraisal of whether the analysis matched the crossover design and the stated endpoint. The posted outcome values and model-based estimates are not reported in the registry record.

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.

R code and output

arm <- c("Speaking Valve", "Open Tracheostomy")
n   <- c(24, 24)
m   <- c(413, 387)
sp  <- c(348, 301.1)
sd  <- sp      # posted standard deviations
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  Speaking Valve  24  413.000  348.000  266.052  559.948
CARM  Open Tracheostomy  24  387.000  301.100  259.857  514.143

11. Multiplicity, Missing Data and Analysis Populations

The record lists a primary six-minute walk outcome and secondary outcomes for change in heart rate, change in oxygen saturation, and active standing time, each described for the first paired sessions. It also indicates nine outcome measures and two analyses. The registry record does not report how these outcomes and analyses were organized into a statistical testing plan, which analysis was primary for each measure, or whether any hierarchy or multiplicity adjustment was used.

As a general statistical concept, testing several outcomes or making several comparisons can increase the chance of obtaining at least one apparently notable result by chance. Prespecified priorities and appropriate adjustment or interpretation can help readers understand that risk. The registry record does not report whether such steps were specified, so no claim about the control of multiplicity is possible.

Missing-data handling is also not reported in the registry record. It does not state how many participants completed the first paired sessions, whether all enrolled participants contributed to each outcome, why measurements might be missing, or how missing observations were handled. The enrollment figure alone does not establish the analysis population or completeness of outcome data.

The record does not report an intention-to-treat or other analysis-population definition. Because this is a non-randomized crossover study with repeated conditions, readers would need to know which participants and sessions contributed to each comparison, and how incomplete pairs were addressed, to evaluate potential selection and missing-data effects. No imputation approach, sensitivity analysis, or per-protocol definition is reported in the registry record. These gaps limit assessment of the robustness of any outcome analysis, especially since the primary outcome estimates themselves are not reported.

12. 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 separate safety figures for the Speaking Valve and Open Tracheostomy groups. For each group, serious events are recorded for 0 participants among 13 at risk, other events are recorded for 0 participants among 13 at risk, and deaths are recorded as 0. The record lists no top serious-event terms.

These are descriptive registry counts. They do not establish that no adverse events occurred outside the categories or reporting period captured by these entries. The record does not provide definitions of serious or other events, the duration or completeness of safety follow-up, or detail about how events were collected. It also does not report a statistical comparison or uncertainty estimate for safety between conditions.

In general, an absence of reported events in a group is not proof that the underlying risk is zero. The amount of information depends on the population observed, event ascertainment, and follow-up, among other factors. These figures should therefore be read as the event counts recorded for the named groups, not as a definitive estimate of comparative safety. No broader safety conclusion is supported by the registry entries alone.

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

The record establishes that the study was designed to compare six-minute walk distance under a Passy-Muir Valve condition and an open-tracheostomy condition, using a crossover arrangement in patients with tracheostomy. It identifies the first paired sessions as the primary outcome timeframe and states that distance is measured in feet. It also records that the study is completed and that allocation was non-randomized.

What the record does not establish is the observed result. Condition-specific distances, a paired estimate of the difference, uncertainty intervals, and a statistical test result are not reported. The direction and size of any difference are therefore unknown from the posted results. The study's completion cannot be interpreted as evidence that the conditions were equivalent, that one condition led to longer distance, or that there was a statistically detectable contrast.

Even if a numerical contrast were available, general interpretation would require attention to its precision, the paired design, the order of conditions, and the non-randomized allocation. The registry record does not report enough analytic detail to determine how those issues were addressed. The safety entries likewise provide counts rather than a detailed comparative analysis.

The appropriate reading is limited: the registry records a clinical question and an intended way to measure ambulation endurance, but does not provide the primary outcome results needed to answer that question. This record alone cannot establish a causal effect, quantify an association, or support a claim about clinical importance. Those conclusions would require reported outcome data and a transparent analysis aligned with the study design.

14. Why This Trial Matters Statistically

This study raises a useful statistical question about measuring performance under two conditions in the same participants. Crossover designs can be efficient for comparing conditions when within-participant measurements are meaningful, because each participant can serve as their own reference. That advantage depends on analyzing the paired data appropriately and accounting for order and time. The registry record describes changing condition order but does not report the method used to handle these design features.

The non-randomized allocation is also central to interpretation. A crossover structure does not automatically make the comparison free from bias: conditions occur at different times, and the order is not described as randomized. Readers need the allocation process and analysis details to judge whether the contrast can be interpreted as an effect of condition or only as an observed difference under the study circumstances. Those details are not reported in the registry record.

Equally important, a clearly stated endpoint is not a substitute for results. The record describes six-minute walk distance and its timing, but does not report the observed values or an estimate of the contrast. Without those results, neither the magnitude nor the precision of the primary comparison can be evaluated. The completed status does not fill that reporting gap.

The record also illustrates why a result needs context beyond a point estimate. General statistical interpretation considers variability, uncertainty, missing measurements, multiplicity, and the analysis population. Those details matter for judging how robust an estimate might be, but are not reported in the registry record. The contribution of this record is therefore mainly to define the comparison and its design features; it does not provide the numerical evidence needed to characterize the outcome.

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 interpretation is that the registry record does not report the primary outcome results. Means, standard deviations, a paired contrast, confidence intervals, and p-values are not reported. Without them, the direction, size, and precision of the comparison cannot be assessed.

The study is explicitly non-randomized, and the record warns that the arms are not a like-for-like control comparison. Although both conditions are described within a crossover format, the record does not explain how condition order was assigned or how the analysis addressed order, session, or time effects. It does not report whether participants completed the same number of paired sessions or how varying session completion was handled.

The record does not provide the statistical analysis plan, analysis population, missing-data methods, or the handling of repeated measurements. It also does not state whether outcome assessors were masked; masking is listed as none. The implications of that entry for measurement and conduct cannot be determined from the record alone.

The described primary timeframe is the first paired sessions, while the broader description refers to alternating sessions and a range from 2 to 6 sessions. How the primary analysis relates to later sessions is not reported. The record also does not provide detailed eligibility criteria, baseline characteristics, or reasons for missing tests. These limitations leave important questions about representativeness, completeness, and analysis choices unresolved.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Does Endurance Improve With the Use of Passy-Muir Valve for Patients With Tracheostomy? — NCT04941456.
• Registry record last updated 2025-12-11; status last verified 2025-12.
• Results first posted 2025-12-11.
• 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.

19. Record Summary

NCT04941456 is a completed, non-randomized crossover study sponsored by Gaylord Hospital, Inc. It compares six-minute walk distance with a Passy-Muir Valve in place and with an open tracheostomy in patients with tracheostomy. The record lists an enrollment of 26 and describes two condition sequences, with the first paired sessions designated as the primary outcome timeframe.

The primary measure is distance walked in feet during a six-minute corridor test, summarized as a mean with standard deviation. The record also lists secondary measures for heart rate, oxygen saturation, and active standing time. The study start is listed as 2021-07-29, and primary completion as 2024-06-24.

The posted results do not report the primary outcome estimates or the statistical comparison. The safety entries record zero serious events, zero other events, and zero deaths in each named group. Analysis methods, missing-data handling, and multiplicity procedures are not reported in the registry record.