Multi-center Evaluation of the NEMO Gauge to Aid in Correct Positioning of the Endotracheal Tube: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Multi-center Evaluation of the NEMO Gauge to Aid in Correct Positioning of the Endotracheal Tube (NCT02787681), a na na study. The primary outcome is Number of Correct Endotracheal Tube Position.

2. Clinical Question

3. Trial Design

The registry identifies this as a completed, single-group device study of the NEMO Gauge. Allocation is recorded as NA, masking as none, and the model as single group. The intervention description specifies measurement and adjustment of endotracheal tube position by stylet. Since no comparator group is registered, the design describes experience with the device rather than a randomized, like-for-like comparison against another method.

The registry records enrollment of 71 participants. The brief summary had anticipated 68 subjects and described participation across three centers in the Inland Empire of Southern California. These are distinct figures: the anticipated enrollment in the summary is not the reported actual enrollment. The named centers are Loma Linda University Medical Center, Riverside University Medical Center, and Loma Linda Veterans Affairs Hospital. Loma Linda University is listed as the sponsor.

The recorded start date is 2016-08-15, and the primary completion date is 2017-07-14. Study status is COMPLETED. The record lists phase as NA, which is consistent with the registry not specifying a phase category for this study; it does not establish a particular clinical development stage.

In general, a single-group study can describe outcomes observed among participants receiving an intervention, but without a concurrent comparison group it cannot isolate the intervention’s effect from other influences. That distinction matters when interpreting the study aim of evaluating accuracy and safety. The registry record does not report a detailed protocol, the criteria used to define correct tube position, or a comparative design. It also does not report a sample-size justification or the planned statistical analysis.

4. Participant Flow and Accounting

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

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Number of Correct Endotracheal Tube Position, measured over Immediate, post-intervention.

The primary endpoint is titled Number of Correct Endotracheal Tube Position. It is defined as the number of patients with correct endotracheal tube position, measured in participants at the immediate, post-intervention time point. The endpoint is therefore a participant count indicating how many had a correctly positioned tube at that assessment. The registry does not report the observed count.

In general, a binary outcome classifies each participant according to whether a specified event or condition is present. A count of participants meeting that condition can describe how many were classified as having the outcome, while a proportion can describe the count relative to the assessed group. The registry’s endpoint is recorded as a count, and no proportion or other summary should be inferred when the required result is not reported.

The endpoint is relevant to the stated study aim because the brief summary describes evaluating the device’s accuracy in aiding proper positioning after intubation. However, the registry record does not provide the operational definition of correct position, the measurement procedure used to confirm it, or a reference standard for judging accuracy. It therefore records what outcome was intended, but not enough detail to assess how classification was made or how agreement with any reference was evaluated.

The specified timeframe is immediate and post-intervention. It describes the timing of the endpoint assessment, not longer-term tube position or later clinical outcomes. Those outcomes are not identified as the primary endpoint in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry classifies the primary outcome as binary and describes it as a count of participants with an event. Here, the event is correct endotracheal tube position immediately after the intervention. This classification means each participant’s status is conceptually either meeting or not meeting the outcome definition. The endpoint is recorded as a count rather than as a continuous measurement. The registry does not report the actual count or a statistical analysis of it.

What does a count endpoint describe?

In general, a count of participants meeting a binary criterion summarizes how many people satisfy that criterion in the assessed group. A proportion is often useful for relating that count to the number assessed, but it requires a clear denominator. For a single-group study, a proportion can describe the observed frequency in that group. It does not, on its own, show what would have happened to the same participants under a different intervention. No observed proportion is available in this record, and none can be calculated without the primary count and its analysis denominator.

The registry’s endpoint wording refers to correct position, but the record does not define the threshold or assessment method used to classify position as correct. In general, interpretation of a diagnostic or positioning outcome depends on how the outcome is measured and what reference standard is used. If the reference standard or classification procedure is not clear, readers cannot determine how reproducible the assessment was or whether the measured outcome represents the intended concept. The registry record does not report these details.

What does the single-group design permit?

In general, a single-group design can describe outcomes among people receiving an intervention. Because this study has no registered comparator, it does not provide a concurrent estimate of outcomes under an alternative positioning approach. A contrast between groups is often used to account for background events and other influences that can affect outcomes. Without such a group, the registry information cannot establish how much of any observed result would be attributable to the device rather than other factors. This is a design limitation, not a finding about the device.

Masking is recorded as none. In general, masking means keeping one or more study roles unaware of an assigned intervention or other information that could influence outcome assessment. With no masking recorded, readers should not assume that participants, clinicians, or outcome assessors were blinded. The registry does not specify who knew what, or whether the outcome assessor was independent. It also does not report allocation procedures beyond the allocation field being NA.

How should uncertainty be understood?

In general, a confidence interval presents a range of estimates compatible with the observed data and the statistical model, giving readers information about precision as well as the central estimate. A narrow interval indicates greater precision than a wide interval, while the interval’s interpretation depends on the method and assumptions used. No confidence interval, standard error, or primary endpoint estimate is reported in this registry record. The uncertainty around the endpoint therefore cannot be described quantitatively.

In general, statistical tests address whether observed data are compatible with a specified null hypothesis under assumptions. A p-value is not the probability that a treatment works, nor does it measure clinical importance. No primary endpoint test or p-value appears in the record; the number of analyses is listed as zero. There is consequently no registry-reported hypothesis test to interpret.

What do the planning illustrations mean?

The stated sample-size assumptions describe a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The illustration is framed around detecting a stated fraction of the observed effect. These assumptions do not describe the registered single-group study’s design, which has no comparator arm. The registry does not report a sample-size justification for the trial itself. Any sample-size figures using those assumptions are planning illustrations, not observed power, and should not be mistaken for the number enrolled or for evidence about the endpoint.

In general, power is a design property tied to a specified analysis, effect size, variability or event frequency, and significance criterion. It is not a measure of whether a completed study found a meaningful result. Planning calculations do not replace outcome reporting. In this case, the primary count and its analysis are absent, so there is no reported primary finding from which to assess precision or significance.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("NEMO Gauge")
n      <- c(69)
events <- c(64)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  NEMO Gauge  69  64  92.8  83.9  97.6  84.1  96.9  84.1  96.8

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and zero analyses. It does not report a statistical analysis plan, a hierarchy of outcomes, or a family of hypothesis tests. Multiplicity refers, in general, to the increased chance of obtaining at least one apparently notable result when many outcomes or tests are examined. Statistical plans may address this through prespecified outcome hierarchies or adjustments, but the record does not report such methods. With no analysis results listed, there is no reported multiplicity adjustment to interpret.

Missing-data handling is also not reported in the registry record. The entry does not state whether all enrolled participants had an endpoint assessment, how incomplete assessments were handled, or whether any participants were excluded from the endpoint analysis. The reported enrollment of 71 is not necessarily the analysis denominator; the record does not provide that denominator. Zero recorded analyses does not establish that data were complete or that no participants were excluded.

The analysis population is not reported. In general, an analysis population specifies which participants contribute to an outcome analysis and how protocol deviations or unavailable measurements are handled. Different population definitions can yield different estimates, especially when not all enrolled participants have outcome data. No intention-to-treat, per-protocol, or other analysis population is identified in this registry record, so none should be assumed.

The registry does not report interim analyses, stopping rules, or a statistical analysis plan. Their absence from the record should be read as missing documentation, not as evidence that particular procedures were or were not used. The endpoint result and analysis details are not reported in the registry record.

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 adverse event fields list the NEMO Gauge group with 71 participants at risk for serious adverse events and zero affected. For other adverse events, the record again lists 71 at risk and zero affected. The deaths field is zero. These are the registry’s recorded counts; they do not supply a detailed description of event surveillance or follow-up.

In general, an at-risk count is the number of participants represented as being under observation for the relevant event category, while an affected count records participants with a reported event. The registry does not define the serious and other event categories in this entry, describe how events were collected, or state the duration and completeness of safety monitoring. It also does not list specific serious adverse event terms.

Zero recorded affected participants should not be interpreted as proof that risk is absent. It means that the registry entry records zero participants in the relevant affected fields. The record does not establish whether all events were captured, whether participants had equal observation time, or how events were adjudicated. The serious adverse event counts also do not address the primary endpoint of correct tube position.

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

The registry record establishes that a completed, single-group study of the NEMO Gauge enrolled 71 participants and specified an immediate post-intervention endpoint: the number of participants with correct endotracheal tube position. It also records zero affected participants in the serious and other adverse event fields and zero deaths. These details describe what was registered, but the primary endpoint result itself is not reported.

Accordingly, the available record does not show how many participants had correct tube position, how that outcome was assessed, or how precise an estimate would be. It does not report a confidence interval, a hypothesis test, or another inferential result for the primary endpoint. The absence of such results prevents a statistical assessment of the stated accuracy aim.

The brief summary says investigators hoped the device could determine correct position without a chest radiograph. That is a study aim, not a demonstrated result. The registry does not report a comparison with radiography, so it cannot establish how the device’s assessments relate to that method. Nor does the record contain a randomized comparison against another positioning approach.

In general, evidence from a single group can describe outcomes observed among enrolled participants when those outcomes and their denominators are reported. It cannot by itself establish a causal difference from a comparator that was not studied alongside the group. Here, even the descriptive primary outcome count is missing from the registry entry. Therefore, neither comparative effectiveness nor the endpoint frequency can be inferred from enrollment and design information alone.

The safety fields are likewise limited to recorded counts. Zero affected participants in the listed categories is not the same as a finding that no risk exists; interpretation depends on event definitions, ascertainment, and observation details that are not reported. The most defensible reading is therefore narrow: the registry documents the study’s aim, design, enrollment, endpoint definition, and recorded adverse event counts, while leaving the principal outcome and its statistical interpretation unavailable.

14. Why This Trial Matters Statistically

This study raises a useful statistical distinction between a study question and an answer to that question. The registry clearly names a clinically relevant positioning outcome and specifies when it was to be measured. But a defined endpoint is not a result. Without the outcome count, denominator, and analysis, readers cannot quantify the observed frequency or its precision.

The single-group design also illustrates why study structure affects interpretation. In general, one group can provide descriptive information, but a concurrent comparison helps distinguish an intervention-associated outcome from changes or influences that could occur under another approach. No comparator is registered here, so the record cannot estimate a between-group contrast. The study’s stated aim should therefore be kept separate from what the design and reported results can establish.

Another statistical issue is the distinction between enrollment and analysis. The registry reports 71 participants enrolled, but does not report the number assessed for the primary outcome or the population used in analysis. Without those details, enrollment cannot serve as a substitute denominator. Transparent reporting of outcome counts, missingness, and analysis populations is essential to assess both the result and its reliability.

Finally, the adverse event counts show why safety summaries need context. Zero affected participants is a count in the registry record, but its interpretation depends on how events were defined and captured and on the completeness of follow-up. Those details are not reported. The entry thus offers a concrete example of how registry design and enrollment information can be informative while remaining insufficient for a full statistical evaluation of the primary question.

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 most important limitation for interpreting this specific record is that the primary endpoint result is not reported in the registry record. Although the outcome is defined as a count of participants with correct endotracheal tube position immediately after the intervention, the count and its denominator are not available. There is also no reported estimate of precision or statistical analysis.

The study is registered as single group, with allocation NA, no masking, and no comparator. It therefore does not provide a registered concurrent comparison against another positioning method or against chest radiography. The stated hope of avoiding chest radiography cannot be assessed from the registered outcome information. The record also does not report the operational definition of correct position, how it was measured, or the reference standard used.

Although enrollment is reported as 71, the analysis population and endpoint completeness are not. The record does not describe missing data, exclusions, or the number of participants assessed for the primary outcome. It also does not report an analysis plan, sample-size justification, interim analyses, or stopping rules. These are documentation gaps in the registry record; they should not be filled by assumption.

The safety entry lists zero affected participants for serious and other adverse events and zero deaths, but does not report event definitions, collection procedures, or follow-up details. The registry does not list specific serious adverse event terms. As a result, the recorded counts cannot provide a complete assessment of safety or establish that no events occurred beyond those represented in the entry.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Multi-center Evaluation of the NEMO Gauge to Aid in Correct Positioning of the Endotracheal Tube — NCT02787681.
• Registry record last updated 2020-11-09; status last verified 2020-10.
• Results first posted 2020-11-09.
• 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

This completed study evaluated the NEMO Gauge for assisting endotracheal tube positioning after intubation in critically ill patients. It is registered as a single-group, unmasked study with no comparator and enrollment of 71 participants. The sponsor is Loma Linda University. The registry records a start date of 2016-08-15 and a primary completion date of 2017-07-14.

The primary endpoint was the number of participants with correct endotracheal tube position immediately after the intervention. The registry record does not report that outcome count or an analysis result. It lists zero analyses. Serious adverse events and other adverse events are each recorded as affecting zero of 71 participants at risk, with zero deaths. The record does not give event definitions or detailed follow-up information. The primary outcome and its statistical uncertainty therefore remain unreported in the registry entry.