Nasotracheal Suction With Tiemann Catheter Compared to the Classic Technique With the Suction Catheter: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Nasotracheal Suction With Tiemann Catheter Compared to the Classic Technique With the Suction Catheter (NCT02261428), a randomized na study. The primary outcome is Number of Attempts Before Entering Trachea.

2. Clinical Question

3. Trial Design

The study is listed as randomized, single-masked, and crossover, with a completed status. Enrollment was 20. The registry record lists muscle weakness as the condition and identifies Catheter Tiemann and Suction catheter as the two device interventions. The specific method of randomization and the identity of the masked party are not reported in the registry record.

A crossover design means participants receive both interventions in some order, rather than remaining in only one treatment group. That structure can allow comparisons within the same participant, but the sequence, any interval between procedures, and any washout procedures are not reported in the registry record. The record also does not state whether the analysis accounted for the paired nature of the measurements.

The primary endpoint was the number of attempts before entering the trachea. The primary outcome summaries list 19 participants for each catheter condition. The reason those summaries do not include all 20 enrolled participants is not reported in the registry record. The record lists six secondary outcomes, including time to entering the trachea, respiratory rate, heart rate, blood pressure, and blood on the catheter.

The record identifies the study sponsor as Grigoriadis Konstantinos and gives a start of 2014-05 and primary completion of 2014-09. The original sample-size justification, planned analysis details beyond the reported analysis, and any interim analyses are not reported in the registry record. The phase is listed as NA.

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: Of the 30 patients screened during the run-in period between May 2014 and September 2014 they received nasotracheal suction all. 10 of them required for pilot study and 20 for the main study. The pilot study was designated as a separate study and the participants was not included in this record.

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.

Population: The participants were non intubated ICU patients who had inadequate cough leading to the inability to mobilize their secretions. The inadequate cough is result of neuromuscular disorders, ICU neuromyopathy, abdominal pain due to surgery and low consiousness due to head injuries.

6. Primary Endpoint

The registry lists the primary outcome as Number of Attempts Before Entering Trachea, measured over An average of 15 seconds.

The primary endpoint is the number of attempts required to insert a catheter into the trachea. The registry record describes it as a mean of a continuous measure, with attempts as the unit and an average 15 seconds as the timeframe. The endpoint focuses on the procedural task of gaining tracheal access, rather than a later clinical outcome. The study description also says the investigators assessed the ability to aspirate bronchial secretions, but the defined primary endpoint is the number of attempts before entering the trachea.

Counting attempts gives a direct measure of how often the procedure had to be tried before the stated access point was reached. A mean describes the average number of attempts across the participants included in the summary. The standard deviation describes the spread of individual observations around that average; it is not a confidence interval and does not by itself indicate how precisely the average has been estimated.

The registry record does not further explain why this endpoint was selected, how an attempt was operationally defined, or how the average 15 seconds timeframe relates to the attempt count. Those details are not reported in the registry record. The record lists time to entering the trachea as a secondary outcome, which is distinct from the primary count of attempts.

7. Results Posted in the Registry

• Suction Catheter: mean 6.79 versus 2.63 on control; difference 4.16 (95% CI 2.20 to 6.12), standardized effect d = 1.35; 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.

Time to Entering Trachea

• 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:
  • Suction Catheter: mean 20.06 versus 10.05 on control; difference 10.01 (95% CI 2.72 to 17.30), standardized effect d = 0.87; z-test p = 0.007.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Suction Catheter than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Respiratory Rate Immediately After 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:
  • Suction Catheter: mean 25.79 versus 26.37 on control; difference -0.58 (95% CI -5.51 to 4.35), standardized effect d = -0.07; z-test p = 0.817.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Suction Catheter and the control. The interval gives the range of effects that remain compatible with the data.

Heart Rate Immediately After 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:
  • Suction Catheter: mean 86.53 versus 87.21 on control; difference -0.68 (95% CI -10.12 to 8.76), standardized effect d = -0.05; z-test p = 0.888.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Suction Catheter and the control. The interval gives the range of effects that remain compatible with the data.

The posted secondary results suggest a mixed pattern rather than a uniform shift across all measured outcomes. The time-to-entering-trachea comparison differs between catheter approaches in the recalculated summaries, while the immediate respiratory-rate and heart-rate comparisons are centered near no difference and have confidence intervals that include zero. The registry record also lists systolic and diastolic blood pressure and blood on the catheter, but numerical results for those outcomes are not reported in the registry record.

The time measure is procedurally related to the primary endpoint, but it captures duration rather than the count of attempts. The immediate physiological measures address a different aspect of the procedure and do not directly replicate the primary measure. Together, the posted results do not establish that every outcome moves in the same direction or that one secondary measure explains the primary result. They provide separate descriptions of the outcomes that were recorded.

All displayed secondary comparisons are unadjusted. General statistical principle: when several outcomes are tested, the chance of at least one apparently notable result can increase, even if none reflects a real underlying effect. Adjustment or a prespecified hierarchy can address some multiplicity concerns, but the registry record does not report whether either was planned or used. The secondary p-value for time to entering the trachea should therefore be interpreted with caution and not treated as an independent confirmation of the primary analysis.

The crossover structure also matters for these outcomes: any within-participant relationship may affect the uncertainty of a comparison. The registry record does not report paired analysis details for the secondary measures. Thus the summaries give a useful account of the posted arm-level values, but do not supply a complete analysis plan or a basis for strong claims across the full set of secondary endpoints.

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

• Time to Entering Trachea
• Respiratory Rate Immediately After Intervention
• Heart Rate Immediately After Intervention
• Systolic Blood Pressure Immediately After Each Intervention
• Diastolic Blood Pressure Immediately After Each Intervention
• Presence of Blood on Catheter Immediately After Each Intervention

9. Statistical Interpretation

10. Statistical Methods Explained

Means and standard deviations. The primary outcome is presented as a mean, with standard deviation as the measure of spread. A mean combines observations into an average; the standard deviation describes how dispersed the observations are around that average. They answer different questions: the mean describes the central value, while the standard deviation describes variation among observations. A standard deviation is not a measure of uncertainty in the estimated mean. The uncertainty in an estimate is instead reflected by a confidence interval or a standard error.

The primary summaries report 2.63 attempts with a standard deviation of 2.24 for Catheter Tiemann, and 6.79 attempts with a standard deviation of 3.75 for Suction Catheter. Each summary has 19 participants. These are marginal, arm-specific summaries. In a crossover study, an analysis may use the fact that the same participant received both interventions. The arm-specific means and standard deviations alone do not describe how each person's measurements under the two procedures relate to one another.

Mean difference and recalculation. A mean difference states the contrast between two group averages in the original measurement unit. The reported recalculated difference is 4.16 attempts, comparing Suction Catheter with Catheter Tiemann. Its 95% confidence interval is 2.196 to 6.124, and its unadjusted p-value is p < 0.001. This recalculation is based on the posted summary statistics. It is not the sponsor's reported analysis, and it does not incorporate within-participant pairing because the paired covariance is not reported.

That distinction is especially relevant for a crossover design. General statistical principle: when the same participant contributes measurements under both conditions, the within-person relationship can affect the standard error of the contrast. A paired analysis uses that relationship; it cannot be reconstructed from separate means and standard deviations alone. The registry record does not report the paired measurements, paired covariance, or enough analysis detail to determine how the sponsor handled the crossover structure.

Wilcoxon (Mann-Whitney) and the reported odds ratio. The sponsor reports a Wilcoxon (Mann-Whitney) analysis and an odds ratio of 3.95, with a 95% confidence interval of 1.79 to 8.73 and p < 0.05. General statistical principle: the Wilcoxon (Mann-Whitney) procedure compares the distributions of observations between groups using their ranks rather than directly comparing means under a normal model. An odds ratio expresses a contrast in odds, but its meaning depends on how the outcome and odds were defined. The registry record does not explain that construction or its interpretation for the number-of-attempts outcome. The reported odds ratio therefore should not be treated as another expression of the recalculated mean difference.

The sponsor's result and the recalculation do not agree in the statistical summary they present. The registry record flags a discrepancy, but does not explain its cause. Accordingly, the sponsor's own analysis takes precedence, while the recalculated result is best understood as a simple unadjusted calculation from the posted arm summaries. It should not be read as a replacement for the registry's reported analysis.

Confidence intervals and p-values. General statistical principle: a confidence interval gives a range of values compatible with the data and a specified analysis, with its width reflecting precision. A p-value describes how unusual data at least as discordant with a null hypothesis would be under that hypothesis and the analysis assumptions. A p-value is not the probability that the null hypothesis is true, and it does not measure clinical importance. Here, the reported sponsor interval pertains to an odds ratio, whereas the recalculated interval pertains to a mean difference. Their scales and analytic bases differ.

Secondary comparisons. Secondary continuous outcomes are reported as means and standard deviations, with recalculated mean differences, confidence intervals, and unadjusted p-values. For example, time to entering the trachea has a recalculated mean difference of 10.01 seconds, a 95% confidence interval from 2.723 to 17.3, and p = 0.007. The immediate physiological summaries have intervals that include zero. General statistical principle: an interval that includes zero for a mean difference is compatible with no difference as well as with values on either side, under the specified analysis. These results are not adjusted for the multiple outcomes examined.

General statistical principle: over-dispersion means that variability is greater than a model assumes. When that occurs, standard errors can be too small and intervals too narrow if the model does not account for the extra variability. The registry record reports standard deviations but does not report a distributional check or a specific over-dispersion assessment. The record also does not report a statistical plan describing model choice, handling of order or period in the crossover, or adjustment for multiple outcomes. No conclusion about those choices should be inferred from the posted summary statistics alone.

11. Confidence Intervals and Precision

A confidence interval communicates the precision of an estimate under a particular analysis. A narrower interval is more precise than a wider one, while an interval spanning a broad range leaves more uncertainty about the size of the contrast. General statistical principle: the interval is not a guarantee that the true value lies within its endpoints, nor does it describe the range of individual participants' outcomes.

For the primary outcome, the recalculated mean difference is 4.16 attempts, with a 95% confidence interval from 2.196 to 6.124. That interval is for the unadjusted difference between the posted arm summaries, not for the sponsor's odds ratio. The sponsor's own analysis reports an odds ratio of 3.95, with a 95% confidence interval from 1.79 to 8.73. These intervals use different measures and analyses, so their widths and endpoints cannot be compared as though they were estimates on the same scale.

The registry record describes the study as a crossover trial, but the recalculation uses only arm-level summary statistics. The relationship between a participant's measurements under each catheter approach is not reported. That missing paired information means the recalculated interval does not reflect a reconstructed within-participant analysis. The registry's own reported interval is the interval associated with the sponsor's analysis; its construction is not fully explained in the record.

For secondary measures, the precision also varies. The time-to-entering-trachea recalculation has a 95% confidence interval from 2.723 to 17.3 seconds. The respiratory-rate interval runs from -5.505 to 4.345 breaths per minute, and the heart-rate interval runs from -10.12 to 8.757 beats per minute. These intervals are broad enough to include zero for the two immediate physiological measures, and their estimates do not establish the absence of a difference. The registry record does not report numerical intervals for the other listed secondary outcomes.

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, not counts of participants enrolled or analyzed. The registry record's planning assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Each illustration uses a stated fraction of the observed effect as the effect to detect. These assumptions describe the illustration, not the trial's original design; the trial's original sample-size assumptions are not reported in the registry record.

For these continuous outcomes, the figures are participants per arm, not total events. The 80% power column means the number of participants per arm that the illustration estimates would be needed to have an 80% chance of detecting the chosen effect under its assumptions. The 90% column gives the corresponding estimate for a 90% chance. These are conventional planning probabilities under a specified model and effect size, not probabilities that the study's conclusion is correct.

The rows use the observed effect, 75% of the observed effect, and 50% of the observed effect. For the primary outcome, the full observed effect corresponds to 9 participants per arm for 80% power and 12 participants per arm for 90% power. Planning for 50% of that observed effect corresponds to 35 participants per arm for 80% power and 47 participants per arm for 90% power. The pattern illustrates a general design principle: smaller effects require more participants to detect with the same planned power.

These figures are hypothetical planning estimates calculated from the observed effect, not observed power. They do not show the power achieved by the completed trial, and they should not be interpreted as evidence that the study was adequately or inadequately designed. In a crossover study, a planning calculation that does not use the within-participant correlation may also differ from one based on the actual paired design; the original design calculation and its assumptions are not reported in the registry record.

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 = 4.160; pooled standard deviation σ = 3.089.
2. n = 2 × (1.96 + 0.842)² × 3.089² / 4.160² = 8.7, rounded up to 9 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 <- 4.16                      # observed difference in means
sigma <- 3.08869713633435                     # 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(2261428)
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 = 9 (80% power), 12 (90% power)
 75% of observed effect: n per arm = 16 (80% power), 21 (90% power)
 50% of observed effect: n per arm = 35 (80% power), 47 (90% power)
power.t.test: 9.7 
Simulated power at n = 9 per arm: 0.762 (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. Analyses Reported by the Sponsor

The sponsor's reported primary analysis is a Wilcoxon (Mann-Whitney) analysis, with an odds ratio of 3.95, a 95% confidence interval from 1.79 to 8.73, and p < 0.05. Separately, the simple unadjusted recalculation from the posted mean and standard deviation summaries gives a mean difference of 4.16 attempts, a 95% confidence interval from 2.196 to 6.124, and p < 0.001. These are different statistical summaries, not two versions of the same estimate.

The registry record flags a discrepancy between the sponsor's result and the recalculation. It does not explain how the odds ratio was defined, why the analyses differ, or whether the sponsor's analysis accounted for the crossover design. The posted summaries also do not include the within-participant pairing needed to reconstruct a paired analysis. For these reasons, the sponsor's own analysis takes precedence; the recalculation is supplementary and should not be presented as a correction to the sponsor's result.

The odds ratio's confidence interval is reported on an odds-ratio scale, while the recalculated interval is on the scale of attempts. The record's lack of detail about the odds-ratio construction limits a fuller comparison. The reported p-values likewise belong to different analyses and should not be compared as if they came from a single prespecified method. The statistical plan and an explanation of the discrepancy are not reported in the registry record.

15. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome and six secondary outcomes. The primary outcome is the number of attempts before entering the trachea. The secondary outcomes include time to entering the trachea, respiratory rate, heart rate, systolic and diastolic blood pressure, and blood on the catheter. The record does not report a multiplicity strategy, such as a hierarchy for testing outcomes or an adjustment to account for multiple comparisons.

General statistical principle: testing several outcomes can increase the chance that at least one result appears statistically notable by chance. An unadjusted p-value addresses a particular comparison under its own test assumptions; it does not account for the number of other outcomes examined. Accordingly, secondary p-values should be viewed as exploratory unless a plan establishes otherwise. The registry record does not report whether the secondary outcomes were prespecified in a detailed statistical analysis plan or how their interpretation was intended to relate to the primary endpoint.

The registry record does not report the original sample-size justification, interim analyses, or a detailed statistical plan. It also does not report the analysis population definition, how missing outcome values were handled, or why the primary summaries include 19 participants per catheter condition when enrollment was 20. The safety summaries list 20 participants at risk in each condition, but those figures do not explain the analysis population for the primary outcome.

Because the design is crossover, missing data and analysis-population definitions can be particularly relevant: a participant may contribute data for one condition but not the other, and the treatment comparison may depend on paired observations. The record does not say whether incomplete pairs were excluded, whether any imputation was used, or whether an intention-to-treat or per-protocol approach was applied. Those details are not reported in the registry record and cannot be inferred from the arm-level summaries.

The record states that the trial was single-masked but does not identify who was masked or describe procedures for maintaining masking. It also does not report the order of interventions, period effects, or any adjustment for sequence. These gaps limit assessment of how the randomized crossover design was implemented and analyzed.

16. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The safety record lists 20 participants at risk for serious adverse events in each catheter group and zero serious adverse events in each group. This means no serious adverse events are recorded among the participants counted at risk in either group. The registry record lists six other adverse events for each group, with 20 participants at risk in each. It does not give further detail about those other events in the information.

The serious adverse event figures are counts, not estimates of comparative risk with confidence intervals. Zero recorded events do not establish that an event is impossible or that the two approaches have identical safety profiles. The record does not report death counts, so deaths are not reported in the registry record. It also does not provide event descriptions, severity details for the other adverse events, or a statistical comparison of safety between catheter conditions.

The study's enrollment was 20, while the safety summaries count 20 at risk for each condition. In a crossover study, participants may be represented under both intervention conditions; these counts should not be added to infer the number of unique participants. The registry record does not provide further detail about safety-population definitions or how events were assigned to intervention periods.

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

The posted primary summaries describe an average of 2.63 attempts for Catheter Tiemann and 6.79 for Suction Catheter, based on 19 participants in each summary. The unadjusted recalculation gives a mean difference of 4.16 attempts, with a 95% confidence interval from 2.196 to 6.124 and p < 0.001. Separately, the sponsor's own analysis reports an odds ratio of 3.95, with a 95% confidence interval from 1.79 to 8.73 and p < 0.05. The registry record flags a discrepancy; the sponsor's own analysis takes precedence.

These results describe the posted data and the statistical analyses attached to them. They do not, by themselves, establish why the estimates differ, how the crossover pairing affected the results, or whether every participant's experience followed the average. A mean is a group-level summary and does not show the full distribution of attempts or individual outcomes. The record does not provide participant-level observations or the paired analysis details.

The primary result also does not establish what happened on the listed secondary outcomes that lack numerical results. The posted secondary summaries show a different pattern across procedure time and immediate physiological measures, and the record does not report numerical findings for blood pressure or blood on the catheter. Unadjusted secondary comparisons are less conclusive when several endpoints are considered.

More broadly, the record describes a randomized, single-masked crossover study with enrollment of 20, but important design and analysis details are not reported. The record does not state the intervention sequence, the details of masking, the rationale for the sample size, or how missing data were handled. These omissions constrain interpretation of precision and generalizability. The results should be read as a description of a small completed study's posted measurements and analyses, not as medical advice or a definitive statement about treatment effects.

18. Why This Trial Matters Statistically

This trial illustrates several statistical issues that arise in clinical research. First, it is registered as a crossover study, so the same participant may contribute measurements under both catheter approaches. That design can make within-person comparisons informative, but the registry record's posted group summaries do not show the paired relationship. Without paired-analysis details, a simple recalculation from separate means and standard deviations may not represent the analysis appropriate to the design.

Second, the record contains a sponsor-reported analysis and a recalculation on different scales. The sponsor reports an odds ratio from a Wilcoxon (Mann-Whitney) analysis, while the recalculation gives a mean difference. Those estimates answer differently formulated statistical questions and cannot be treated as interchangeable. The flagged discrepancy makes transparent reporting of the estimand, test, and calculation especially important. The record does not explain how the odds ratio was constructed or reconcile the two analyses.

Third, the primary outcome is a procedural count, while the secondary outcomes include procedure time and immediate physiological measures. Considering multiple outcomes requires care: a notable unadjusted secondary p-value does not automatically confirm the primary finding. The record does not report a multiplicity plan or a detailed analysis plan, so readers cannot determine how the outcomes were prioritized in advance.

Finally, the planning illustrations show how required sample sizes can change with the effect targeted. Smaller effects require more participants under the stated planning assumptions. Those illustrations do not reveal the study's original design rationale and are not observed power. Together, these features make the study a useful example of why design, analysis, precision, and reporting details all matter when interpreting clinical-trial results.

19. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

Several limitations specific to this record constrain interpretation. Enrollment was 20, while the primary arm summaries include 19 participants per catheter condition. The reason for this difference is not reported in the registry record. The record does not provide participant-level data, so the summaries cannot show the distribution of attempts, unusual observations, or the within-person relation between the two crossover measurements.

The crossover design is named, but the intervention sequence, interval between procedures, possible period effects, and handling of paired observations are not reported. The registry record also does not identify who was masked under the single-masking designation. These omissions make it difficult to assess how the design was implemented and whether the reported analysis reflects its structure.

The sponsor's reported odds-ratio analysis differs from the unadjusted mean-difference recalculation. The record flags the discrepancy but does not explain the odds-ratio construction or reconcile the results. The sponsor's own analysis takes precedence, but the missing explanation limits reproducibility and interpretation. A detailed statistical analysis plan and the original sample-size justification are not reported.

Only some secondary outcomes have numerical summaries. The record lists blood pressures and blood on the catheter, but their results are not reported in the registry record. The registry record also does not report a multiplicity strategy, missing-data methods, analysis-population definitions, or interim analyses. The safety summary gives counts but does not provide details about the six other adverse events in either group, and death counts are not reported.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Nasotracheal Suction With Tiemann Catheter Compared to the Classic Technique With the Suction Catheter — NCT02261428.
• Registry record last updated 2015-03-17; status last verified 2015-03.
• Results first posted 2015-03-17.
• 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.

23. Record Summary

The registry record describes a completed randomized, single-masked crossover study comparing nasotracheal suction with a Tiemann catheter against a suction catheter. It lists muscle weakness as the condition, enrollment of 20, and the sponsor as Grigoriadis Konstantinos. The study start is recorded as 2014-05, with primary completion in 2014-09.

The primary endpoint is the number of attempts before entering the trachea. Its posted summaries include 19 participants per catheter condition. The sponsor reported a Wilcoxon (Mann-Whitney) analysis with an odds ratio of 3.95, a 95% confidence interval from 1.79 to 8.73, and p < 0.05. A separate unadjusted recalculation gives a mean difference of 4.16 attempts, with a 95% confidence interval from 2.196 to 6.124 and p < 0.001. The record flags a discrepancy, so the sponsor's own analysis takes precedence.

The record lists six secondary outcomes and reports some numerical summaries, but results for the listed blood-pressure and catheter-blood outcomes are not reported in the registry record. Serious adverse events are recorded as zero in each catheter group, with 20 at risk in each; other adverse events are recorded as six in each. Important details about crossover implementation, missing data, multiplicity, and the original design assumptions are not reported in the registry record.