Comparison of Oxygenation and Ventilation With a Novel Nasal Mask Versus Standard of Care During Colonoscopy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Comparison of Oxygenation and Ventilation With a Novel Nasal Mask Versus Standard of Care During Colonoscopy (NCT03139448), a randomized na study. The primary outcome is Time to First Intervention.

2. Clinical Question

The clinical question concerns the timing of the first intervention for airway management during colonoscopy, rather than a direct measure of colonoscopy completion or a long-term outcome. The registry describes the trial objective as comparing oxygenation and ventilation with the novel nasal mask versus standard care with a nasal cannula. It also notes that the mask provides nasal continuous positive airway pressure and nasal-mask ventilation.

The posted primary results report a mean time to first intervention of 10.0 minutes in the nasal-cannula group and 19.0 minutes in the SuperNO2VA group. The reported mean difference, expressed as SuperNO2VA minus nasal cannula, is 9.0 minutes, with a confidence interval from 5.302 to 12.7 minutes and an unadjusted p-value of <0.001. These results describe the recorded groups and endpoint. They do not, by themselves, establish how the devices perform in settings or populations not represented in the registry record.

3. Trial Design

The registry record describes a prospective randomized trial with a parallel-group design and no masking. It lists the study as completed, with enrollment of 174. The listed study start date is 2017-05-17 and the primary completion date is 2017-10-06. The record identifies Vanderbilt University Medical Center as the sponsor and lists phase as NA.

Participants were allocated to oxygen via nasal cannula, identified as standard of care, or oxygen via the SuperNO2VA nasal mask. The nasal-cannula arm used oxygen flow rates selected according to routine standard of care at Vanderbilt University Medical Center. For the SuperNO2VA arm, the description specifies connection to the anesthesia machine, an oxygen flow rate of 10L/min, and an APL valve setting of 10 cm H2O. The registry does not report additional procedural details about how allocation was generated or concealed, or how adherence to the assigned device was assessed.

The primary outcome was time to first intervention for airway management. Its stated measurement period is “Usually 5 minutes,” and the outcome definition starts at the beginning of the standard-of-care propofol bolus and/or start of propofol infusion and ends when the first airway-management intervention is initiated. Secondary outcomes listed in the record cover receiving airway-management interventions, duration of intervention, oxygen saturation, and ventilation measures including tidal volume, respiratory rate, and minute ventilation.

Arm-level primary results are reported for 73 participants in the nasal-cannula group and 63 participants in the SuperNO2VA group. The registry does not explain the relationship between these outcome-specific counts and the overall enrollment, nor does it report reasons for missing outcome data or exclusions from the analyses. The randomized, parallel design supports a direct group comparison, but the unmasked design and the details not reported in the registry record matter when interpreting the results.

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

Reasons for not completing this period:

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 Time to First Intervention, measured over Usually 5 minutes.

The primary endpoint is time to first intervention for airway management, measured in minutes. It is defined as the interval from the beginning of the standard-of-care propofol bolus and/or start of propofol infusion to initiation of the first airway-management intervention. The registry gives the timeframe as “Usually 5 minutes.”

This endpoint captures how long the patient went before an airway-management intervention was initiated under the study conditions. It is a timing outcome: a longer recorded interval means that the first intervention occurred later, not necessarily that no intervention was needed or that every aspect of oxygenation and ventilation was better. The registry does not define the range or types of interventions included in the primary endpoint beyond describing them as interventions for airway management.

A mean is used to summarize a continuous time measure across participants in each group. The record reports the mean and standard deviation for each arm, allowing readers to see both the average time and the spread of individual times. A between-group mean difference then expresses the contrast in average time on the original minutes scale. The endpoint is relevant to the stated device comparison because airway-management interventions are part of the respiratory support context during colonoscopy. It should be read alongside the secondary measures, which assess other aspects of intervention use, oxygen saturation, and ventilation rather than treating the primary timing outcome as a complete summary of respiratory status.

7. Results Posted in the Registry

• Oxygen Via SuperNO2VA Nasal Mask: mean 19.00 versus 10.00 on control; difference 9.00 (95% CI 5.30 to 12.70), standardized effect d = 0.81; z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Number of Subjects Receiving Interventions for Airway Management

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Oxygen Via SuperNO2VA Nasal Mask: 22.2% (14/63) versus 63.0% (46/73) on control; risk difference -40.8 percentage points (95% CI -55.9 to -25.7), risk ratio 0.35 (0.22–0.58); unadjusted two-proportion z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically lower for Oxygen Via SuperNO2VA Nasal Mask than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Duration of Intervention

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Oxygen Via SuperNO2VA Nasal Mask: mean 12.00 versus 19.00 on control; difference -7.00 (95% CI -16.99 to 2.99), standardized effect d = -0.24; z-test p = 0.170.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Oxygen Via SuperNO2VA Nasal Mask and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants With Oxygen Saturation- Reading Below 90%

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Oxygen Via SuperNO2VA Nasal Mask: 4.8% (3/63) versus 21.9% (16/73) on control; risk difference -17.2 percentage points (95% CI -28.0 to -6.3), risk ratio 0.22 (0.07–0.71); unadjusted two-proportion z-test p = 0.004.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically lower for Oxygen Via SuperNO2VA Nasal Mask than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The secondary outcomes broaden the picture beyond the primary timing measure. They cover whether airway-management interventions were received, intervention duration, oxygen saturation summaries and threshold events, and ventilation measures. The posted secondary results include comparisons for intervention receipt, duration, and participants with oxygen saturation readings below 90%. Other listed secondary measures do not have results described in the registry record. This pattern means that the secondary results offer some additional context, but do not form a complete report of every respiratory measure named in the study record.

Conceptually, intervention receipt and intervention duration are closely related to the primary endpoint, but they ask different questions. Time to first intervention concerns when an intervention begins; intervention receipt concerns whether one was recorded; duration concerns how long intervention continued. Oxygen saturation outcomes address a measured aspect of oxygenation, while ventilation measures concern different physiological quantities. Agreement across related outcomes may lend context to the primary comparison, but it cannot eliminate uncertainty about outcome definitions, missing observations, or analysis choices.

The secondary comparisons should carry less inferential weight than the primary result because they are unadjusted and the registry record does not report a multiplicity strategy or identify which secondary outcomes were confirmatory. When several outcomes are examined, the chance of at least one apparently strong result can increase. A nominal p-value for an individual secondary outcome does not account for the full set of outcomes considered.

The record lists eight secondary outcome measures, while the posted secondary results cover only some of them. It does not report why results for the remaining listed measures are unavailable, whether analyses were planned but not posted, or how missing data were handled. Thus, the secondary pattern can be used to understand the scope of the posted evidence, but should not be treated as a definitive, comprehensive account of all oxygenation and ventilation outcomes measured in the trial.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Number of Subjects Receiving Interventions for Airway Management
• Duration of Intervention
• Oxygen Saturation Reading- Median
• Oxygen Saturation- Lowest Reading
• Number of Participants With Oxygen Saturation- Reading Below 90%
• Tidal Volume (VT)
• Respiratory Rate (RR)
• Minute Ventilation (MV)

9. Statistical Interpretation

10. Statistical Methods Explained

Statistical comparisons are most useful when the measure, direction, uncertainty, and analysis context are read together. The primary outcome is a continuous time measure. The record reports a mean and standard deviation for each group, then a mean difference with a confidence interval and an unadjusted p-value. These statistics answer related but distinct questions: the means describe the observed group averages, the difference describes their contrast on the original time scale, the confidence interval conveys uncertainty about that contrast, and the p-value assesses compatibility with a specified no-difference model under the assumptions of the test.

What does the mean difference represent?

The comparison is expressed as the SuperNO2VA mean minus the nasal-cannula mean. A positive estimate therefore indicates a higher mean time in the SuperNO2VA group for this endpoint. The reported estimate is 9.0 minutes. Because it is in the endpoint’s original units, it can be interpreted directly as a difference in average elapsed time. It does not describe a difference for every participant, nor does it indicate how often a particular individual would require an intervention.

The standard deviation describes variation among observations within an arm; it is not the uncertainty of the arm mean. The registry reports standard deviations of 12.0 and 10.0 minutes in the nasal-cannula and SuperNO2VA groups, respectively. Standard deviations help readers understand that participant-level times vary, while the confidence interval for the difference concerns uncertainty about the group contrast. These quantities should not be used interchangeably.

How should the confidence interval and p-value be read?

The reported confidence interval for the primary mean difference ranges from 5.302 to 12.7 minutes. In general, a confidence interval gives a range of values compatible with the data under the analysis method and its assumptions. Its width reflects precision: narrower intervals indicate more precise estimates, while wider intervals leave more uncertainty about the magnitude. The interval does not cross zero, which is consistent with the unadjusted p-value of <0.001 for a no-difference comparison. The p-value is not the probability that the null hypothesis is true, and it does not measure clinical importance.

The registry record does not report the statistical test used for the primary result, the covariates considered, or a prespecified analysis plan. The presented p-value is unadjusted, so it should not be read as accounting for multiple outcomes or analyses. The record also does not report an adjusted analysis that would address any potential baseline imbalance or other measured factors.

Why does the endpoint’s distribution matter?

Time to an intervention is measured in minutes, but participant times may not follow a symmetric distribution. A mean and standard deviation can be sensitive to unusually long observations. The posted summary does not provide participant-level data or distributional diagnostics, so it is not possible to assess skewness, influential observations, or whether the method’s assumptions fit the observed times. This is a limitation of interpretation, not evidence that the reported analysis is invalid.

In general, over-dispersion means that outcomes vary more than a model’s assumed distribution allows. For count or binary outcomes, that can make standard errors too small if ignored. It is not a specific reported issue for this trial, and the registry does not describe an over-dispersion assessment. The primary outcome is reported as a continuous mean rather than a count, so the key general issue is whether the chosen summary and analysis adequately reflect the distribution of observed times.

What does randomization contribute?

Random allocation is intended to make the treatment groups comparable on average before the intervention, including for characteristics that may not have been measured. That supports an interpretation of between-group differences as associated with assignment within the trial. Randomization does not guarantee balance in every sample, and the registry does not report baseline characteristics or the allocation procedure. In addition, the study was unmasked. For an outcome whose endpoint depends on a provider initiating an intervention, awareness of the assigned device could influence the timing decision. The record does not report blinded outcome assessment or other steps taken to limit such influence.

The posted outcome-specific arm counts differ across some outcomes, and the record does not explain missingness, exclusions, or analysis-population definitions. Those details are important because an analysis of only participants with recorded outcomes can be affected if outcome availability is related to assignment or clinical course. Without this information, the arm-level comparisons can be described, but the handling of all randomized participants cannot be verified from the registry record.

What is the role of the secondary comparisons?

The secondary outcomes include binary counts and other continuous measures. A risk difference for a binary outcome is a difference between group proportions on the probability scale; a negative estimate means a lower observed proportion in the SuperNO2VA group under the comparison’s stated direction. Ratios such as risk ratios or odds ratios express the same binary contrast on a relative scale. For continuous outcomes, a mean difference remains in the outcome’s original units. Each scale answers a different interpretive question, and the scales should not be treated as interchangeable.

These endpoint comparisons are listed as unadjusted, and no reported analyses are listed in the registry record. If many outcomes are examined without a stated multiplicity plan, some apparently notable results may occur by chance. That is why secondary findings are best interpreted as supportive or exploratory unless the registry record documents a prespecified strategy that gives them confirmatory status. The record does not report such a strategy.

For the posted primary comparison, the registry’s discrepancy flag is false. No separate sponsor analysis is identified as conflicting with the displayed estimate. The data therefore support a plain reading of the posted estimate and uncertainty, while the missing analysis details and unmasked design remain relevant limitations.

11. Confidence Intervals and Precision

Precision concerns how narrowly the data locate the estimated group difference. For the primary endpoint, the reported mean difference is 9.0 minutes and its confidence interval runs from 5.302 to 12.7 minutes. The interval indicates uncertainty about the size of the difference: values across that range are compatible with the estimate under the statistical method and its assumptions. The interval is entirely above zero, so the posted primary comparison is consistent with a longer average time to first intervention in the SuperNO2VA group.

The interval is not a prediction range for individual participants. It does not mean that every participant’s time lies between its limits, and it does not show the full spread of observed times. The group standard deviations—12.0 minutes for nasal cannula and 10.0 minutes for SuperNO2VA—describe participant-level dispersion in a different way. Together, the group summaries and confidence interval show both that the averages differ and that individual times vary.

The precision of a confidence interval depends on the amount and variability of the observed data and on the analysis method. The primary arm counts are 73 and 63, and the reported standard deviations are substantial relative to the endpoint scale. The registry record does not provide a method description sufficient to independently assess the interval’s assumptions, nor does it provide participant-level values or diagnostics. The reported interval should therefore be read as the registry’s estimate of uncertainty, not as a guarantee about the true value or a statement about clinical importance.

A small p-value and a precise estimate are related but not identical ideas. The unadjusted p-value is <0.001, while the confidence interval communicates a range of plausible effect magnitudes. Neither statistic establishes whether a difference is important in practice; the registry record does not report a threshold for clinical importance.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size figures are planning illustrations based on the observed effect, not the trial’s original design calculation. For the continuous primary endpoint, and for the other non-time-to-event comparisons, the figures are participants per arm. A time-to-event planning display would instead report total events, but the primary outcome is reported as a mean of a continuous measure, so the per-arm interpretation applies.

The planning assumptions listed in the registry materials are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect equal to the stated fraction of the observed effect. The figures are given for planning at 80% and 90% power. In plain language, power is the chance that a study would detect an effect of the specified size under the planning assumptions if that effect were present. The 80% column gives the per-arm planning count for that target; the 90% column gives the per-arm count for the higher target.

Rows for planning for 75% or 50% of the observed effect assume a smaller difference than the full observed effect. Smaller effects are harder to distinguish from random variation, so they require more participants under otherwise unchanged assumptions. This explains why the planning counts rise as the assumed effect becomes smaller. These calculations are not observed power: they do not measure the probability that this completed trial detected an effect, and they do not establish whether the trial was adequately powered for its original objectives.

The registry record does not report the original sample-size justification or the assumptions used when the trial was designed. The planning displays should therefore be read as hypothetical illustrations derived from the observed estimates, not as a reconstruction of the trial’s prespecified plan. Their value is to show how the required per-arm enrollment would vary across effect-size and power targets if the stated assumptions were used.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 9.000; pooled standard deviation σ = 11.119.
2. n = 2 × (1.96 + 0.842)² × 11.119² / 9.000² = 24.0, rounded up to 24 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 9                      # observed difference in means
sigma <- 11.1194330361209                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(3139448)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 24 (80% power), 33 (90% power)
 75% of observed effect: n per arm = 43 (80% power), 58 (90% power)
 50% of observed effect: n per arm = 96 (80% power), 129 (90% power)
power.t.test: 25 
Simulated power at n = 24 per arm: 0.782 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome and multiple secondary outcomes. It does not report a multiplicity adjustment, a hierarchical testing strategy, or another plan for controlling the chance of false-positive findings across outcomes. The posted comparison p-values are unadjusted. Consequently, an individual secondary p-value should not be interpreted as if it were the only statistical test conducted. The primary endpoint has a distinct status in the record, but the registry does not provide a complete analysis plan to clarify the intended confirmatory hierarchy.

The record does not report how missing outcome data were handled. It also does not describe the reasons that outcome-specific participant counts differ, whether missingness was related to assigned group or clinical events, or whether any imputation or sensitivity analyses were performed. This matters because complete-case comparisons can be misleading when the availability of measurements is related to the outcome or treatment assignment. Without the missing-data description, it is not possible to assess that risk.

The registry record does not define an intention-to-treat, per-protocol, or other analysis population for the primary or secondary outcomes. Randomization describes how assignment was made, but it does not by itself show that all randomized participants were included in each analysis according to assignment. The reported arm counts should therefore be understood as outcome-specific reported counts; the record does not explain participant flow or analysis exclusions.

The study was unmasked, and the primary endpoint depends in part on a provider’s decision to initiate an airway-management intervention. The record does not report whether outcome assessment was blinded or whether intervention criteria were standardized beyond the endpoint description. No reported analyses are listed in the record. Together, the absent analysis details, missing-data information, and multiplicity plan limit the ability to verify how the posted estimates were selected and how robust they are to alternative analytic choices.

15. 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 reports serious adverse event figures separately for the two device groups. For oxygen via nasal cannula, 79 participants were listed as at risk for serious adverse events and 0 serious adverse events were reported. For oxygen via the SuperNO2VA nasal mask, 70 were listed as at risk and 0 serious adverse events were reported. The record also reports 0 deaths in each group.

These figures mean that no serious adverse events or deaths were recorded in the listed groups in this registry report. They do not establish that the risk of serious adverse events is absent. When no events are observed, the data provide limited information about how uncommon events might be, and the registry record does not give confidence intervals for these safety counts.

The registry also reports 0 other adverse events in each group, using the same listed at-risk counts. It does not provide additional detail about adverse-event definitions, duration of safety follow-up, or how events were collected. The safety figures should therefore be read as the reported event counts within the registry’s recorded scope, not as a complete guarantee of safety or a comparison capable of ruling out uncommon harms.

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

The posted primary result is a group-level difference in the average time to first airway-management intervention during colonoscopy. The SuperNO2VA group had a reported mean of 19.0 minutes, compared with 10.0 minutes in the nasal-cannula group. The mean difference was 9.0 minutes, with a confidence interval from 5.302 to 12.7 minutes and an unadjusted p-value of <0.001. These statistics describe the observed endpoint and its estimated group contrast.

The result does not mean that every participant in the SuperNO2VA group waited longer before an intervention, that no intervention was required, or that the device improved every aspect of oxygenation or ventilation. The primary endpoint records timing, and its interpretation is limited to the first intervention as defined in the registry. Secondary outcomes address other questions and should be considered on their own terms.

The trial was randomized, which supports comparison between assigned groups, but it was unmasked. Because a clinician initiates the intervention that defines the primary endpoint, knowledge of the assigned device could potentially affect the timing of that decision. The registry record does not report whether assessment was blinded or whether intervention thresholds were standardized. It also does not report the analysis population, missing-data methods, or a prespecified multiplicity approach.

The findings apply to the participants and procedural conditions represented in the record. The registry does not establish that the same estimates would apply to other populations, procedures, oxygen protocols, or clinical settings. The posted data should not be used to infer outcomes that were not measured or reported. In particular, the primary result is not a complete measure of clinical benefit, and the absence of reported serious adverse events does not prove that uncommon events cannot occur.

17. Why This Trial Matters Statistically

This trial illustrates how a clinical comparison can produce a result that is statistically clear for its primary endpoint while still requiring careful interpretation. The mean difference is expressed directly in minutes, and its confidence interval stays above zero. That makes the direction and estimated scale of the primary contrast easy to describe. At the same time, the standard deviations show meaningful variation in observed times, reminding readers that a group average does not describe every participant’s experience.

The endpoint also highlights the distinction between a physiological measure and a care-process measure. Time to first airway-management intervention reflects both the patient’s course and the provider’s decision about when to intervene. In an unmasked trial, that decision may be influenced by knowing which device is being used. The endpoint remains relevant to the trial’s objective, but its interpretation depends on recognizing this potential measurement and decision pathway.

The secondary outcomes show why a single statistically notable result should not stand in for the entire respiratory profile. Intervention occurrence, intervention duration, oxygen saturation, and ventilation measures address different domains. A multiplicity plan and a clear account of which outcomes were confirmatory would help readers distinguish planned inference from exploratory signals. Those details are not reported in the registry record.

Finally, sample-size illustrations based on observed effects can help show how precision and detectable effect size are related, but they cannot substitute for the original design rationale. The trial record does not report that rationale. This makes the distinction between prospective design assumptions and retrospective planning illustrations especially important when assessing what the study was designed to establish.

18. 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 trial-specific limitations affect interpretation. The study was unmasked, and the primary endpoint depends on the timing of a provider-initiated airway-management intervention. The registry record does not report whether intervention criteria were standardized or whether the outcome assessment was blinded. This leaves open the possibility that awareness of assignment affected decisions about when to initiate an intervention.

The record does not report detailed eligibility criteria, baseline characteristics, the randomization procedure, allocation concealment, or a participant-flow account. It reports overall enrollment of 174, while primary-outcome results are available for 73 participants in the nasal-cannula group and 63 in the SuperNO2VA group. The record does not explain the difference between enrollment and these outcome-specific counts or identify reasons for missing or excluded observations.

The original sample-size justification and statistical analysis plan are not reported. The available planning figures are illustrations based on observed effects, rather than documented original design assumptions. The record also does not specify the test underlying the primary comparison, whether any covariate adjustment was intended, or how multiple outcomes were addressed. Secondary results are unadjusted, and results are not posted for every listed secondary measure.

Finally, the reported outcomes and safety counts do not provide a complete assessment of all possible clinical consequences. The registry gives no detail about follow-up beyond the stated outcome timeframes, and the zero serious adverse event counts cannot rule out uncommon events. These limitations concern what can be concluded from the registry record; they do not change the posted estimates themselves.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Comparison of Oxygenation and Ventilation With a Novel Nasal Mask Versus Standard of Care During Colonoscopy — NCT03139448.
• Registry record last updated 2019-02-05; status last verified 2019-02.
• Results first posted 2019-02-05.
• 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.

22. Record Summary

The registry record describes a completed, prospective randomized, parallel-group trial with no masking. It compared oxygen via nasal cannula, identified as standard of care, with oxygen via the SuperNO2VA nasal mask during colonoscopy. Enrollment was 174, and Vanderbilt University Medical Center is listed as sponsor.

The primary outcome was time to first intervention for airway management. The posted mean difference was 9.0 minutes in the direction of a longer mean time in the SuperNO2VA group, with a confidence interval from 5.302 to 12.7 minutes and an unadjusted p-value of <0.001. Secondary outcomes cover intervention use and duration, oxygen saturation, and ventilation measures; results are posted for some but not all listed secondary measures.

No serious adverse events or deaths are reported in either group. The registry record does not report the original sample-size justification, a statistical analysis plan, missing-data methods, or a multiplicity strategy. Those omissions limit assessment of the full analysis context and the scope of conclusions.