90° Rotation Technique for LMA FlexibleTM Insertion: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for 90° Rotation Technique for LMA FlexibleTM Insertion (NCT03028896), a randomized na study. The primary outcome is First Attempt Success Rate.

2. Clinical Question

The trial addresses a procedural comparison rather than a comparison of medicines. Its central outcome is whether insertion succeeds at the first attempt, which captures both the occurrence of an initial successful placement and the need for another attempt. The registry’s stated rationale is that rotation had been described as improving success with conventional LMA, while its effect with LMA FlexibleTM was not known. That rationale frames the research question; it does not establish what the trial would find.

The registry also lists insertion time and oropharyngeal leak pressure at induction, as well as the number of participants with blood staining on the airway at post-op 1min. These outcomes address different aspects of the procedure, so they complement rather than replace the primary question. The results need to be read as comparisons between the randomized groups, with attention to the size and uncertainty of each difference.

3. Trial Design

The registry describes a randomized, triple-masked, parallel-group trial. Participants were assigned to the standard or rotational insertion technique, and the posted primary outcome gives separate results for the two groups. The record reports enrollment of 132. For the primary endpoint, the posted group denominators are 63 for standard and 66 for rotational; the registry does not explain the relationship between the enrollment figure and those endpoint denominators.

The standard procedure used a neck-flexed, head-extended position. The mask was held like a pen, with the index finger placed at the junction of the cuff and tube, and pushed backward while maintaining pressure against the palate until resistance was felt. In the rotational procedure, the entire cuff was first inserted inside the mouth. The LMA FlexibleTM was then rotated counter-clockwise through 90°, advanced through the right side of the tongue until resistance was felt, and returned in the hypopharynx.

The registry lists the study phase as NA and the overall status as completed. The recorded start date is 2015-04-02, and the primary completion date is 2016-03-04. Seoul National University Bundang Hospital is identified as sponsor. The record does not describe which groups of people were masked, how assignment was generated or concealed, or the trial’s original sample-size justification; those details are not reported in the registry record.

The primary endpoint is first-attempt success at induction. Three secondary outcomes are also posted: insertion time, oropharyngeal leak pressure, and blood staining. The registry does not provide reported analyses for these outcomes beyond the posted arm summaries and comparisons. Randomization provides the framework for comparing assigned techniques, but interpretation still depends on the available outcome data, their precision, and the completeness of the statistical reporting.

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 First Attempt Success Rate, measured over at induction.

The primary endpoint is the first-attempt success rate of LMA FlexibleTM insertion, measured as the count of participants whose insertion succeeded on the first attempt. The timeframe is at induction. In the standard group, 59 of 63 participants were recorded as successful; in the rotational group, 65 of 66 were recorded as successful.

This endpoint is used because it directly represents the trial’s central procedural question: whether the airway device could be inserted successfully at the initial attempt under one technique or the other. A binary outcome separates participants with first-attempt success from those without it, making the comparison interpretable as a difference in the probability of that event. It does not, by itself, describe what happened after an unsuccessful first attempt or quantify the number of later attempts.

In general, a first-attempt endpoint can be useful for comparing techniques because it focuses on an immediate, clearly defined procedural event. Its interpretation remains specific to the recorded definition, setting, and assessment time. The registry states the outcome and timeframe, but does not further define success criteria, assessment procedures, or analysis populations. Those details are not reported in the registry record.

7. Results Posted in the Registry

• Rotational: 98.5% (65/66) versus 93.7% (59/63) on control; risk difference 4.8 percentage points (95% CI -1.9 to 11.5), risk ratio 1.05 (0.98–1.13); unadjusted two-proportion z-test p = 0.155.

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.

Insertion Time

• 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:
  • Rotational: mean 9.70 versus 10.50 on control; difference -0.80 (95% CI -2.42 to 0.82), standardized effect d = -0.17; z-test p = 0.334.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Rotational and the control. The interval gives the range of effects that remain compatible with the data.

Oropharyngeal Leak Pressure

• 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:
  • Rotational: mean 20.50 versus 19.80 on control; difference 0.70 (95% CI -0.88 to 2.28), standardized effect d = 0.15; z-test p = 0.385.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Rotational and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants With Blood Staining on the Laryngeal Mask Airway

• 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:
  • Rotational: 4.5% (3/66) versus 1.6% (1/63) on control; risk difference 3.0 percentage points (95% CI -2.9 to 8.9), risk ratio 2.86 (0.31–26.81); unadjusted two-proportion z-test p = 0.333.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Rotational and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes span different dimensions of the insertion procedure: time, leak pressure, and blood staining. Their point estimates do not form a single uniformly favorable pattern for one technique. They should be viewed as complementary procedural measures, not as substitutes for the primary first-attempt endpoint. The registry results do not provide a unified composite measure across these outcomes.

Across the secondary comparisons, the confidence intervals include no difference. That means the posted estimates leave uncertainty about the direction and size of each contrast. The results do not, by themselves, demonstrate that the techniques are identical on these measures. Nor should a directional point estimate be treated as conclusive evidence of a difference when the interval remains compatible with no contrast.

These outcomes relate to the primary result by adding context about other recorded aspects of insertion. A first-attempt success comparison can address the central procedural question, while time and pressure describe separate continuous measurements and blood staining is another binary event. Consistency across outcomes can sometimes strengthen interpretation, but the measures have different meanings and the registry does not report a prespecified hierarchy or combined analysis.

The secondary p-values are unadjusted. In general, examining multiple outcomes increases the chance that at least one result may appear unusual by chance, even when no real differences exist. Without a reported multiplicity plan, each secondary finding should carry less weight than a single prespecified primary result. The registry does not report adjusted secondary analyses or a detailed plan for interpreting multiple comparisons; those details are not reported in the registry record.

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

• Insertion Time
• Oropharyngeal Leak Pressure
• Number of Participants With Blood Staining on the Laryngeal Mask Airway

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is binary: each participant is counted as either having or not having first-attempt success. For a binary outcome, a risk or proportion describes the fraction of participants with the event in a group. The registry posts proportions of 0.936 in the standard group and 0.985 in the rotational group. A risk difference expresses the contrast between those proportions on an absolute scale. The reported estimate is 0.048 for rotational relative to standard.

A risk difference is often straightforward to interpret because it describes an absolute change in event probability. It is not the only useful scale. A relative risk compares the event probability in one group with the probability in the other, while an odds ratio compares event odds. These relative measures can look quite different from an absolute difference, especially when an event is frequent or when the event count is small. The registry posts a relative risk of 1.052 and an odds ratio of 4.407 for the primary comparison, each with its own confidence interval. Those estimates should be read with their intervals, not as precise stand-alone descriptions.

The p-value reported for the primary comparison is unadjusted. In general, a p-value measures how unusual data at least as incompatible with a null hypothesis would be if that null model and its assumptions were true. It is not the probability that the null hypothesis is true, and it does not measure the size or practical importance of an effect. A p-value should be considered alongside the estimate and its confidence interval. The registry does not report the test specification or detailed analysis procedure, so those details are not reported in the registry record.

What does a confidence interval communicate?

In general, a confidence interval is a range of effect estimates compatible with the observed data under a particular statistical procedure and its assumptions. It conveys precision: a narrower interval indicates a more concentrated range of estimates, while a wider interval leaves greater uncertainty. The primary risk-difference interval runs from -0.019 to 0.115. Because it spans values on both sides of no difference, the results are compatible with no contrast as well as with contrasts in either direction. The interval does not assign a probability to each possible value.

Why use more than one effect scale?

Absolute and relative measures answer related but distinct questions. The risk difference expresses the contrast in event proportions, whereas relative risk and odds ratio describe the contrast in relative terms. When success is common in both groups, the odds ratio can be numerically far from the relative risk and may be unstable when event counts are limited. In general, the choice of scale should reflect the scientific question and be interpreted with uncertainty. The registry posts several scales, but does not report a reason for selecting one as the primary analysis scale beyond identifying the endpoint itself.

How should continuous outcomes be read?

The two continuous secondary outcomes are reported as means with standard deviations. In general, a mean describes the average measured value in a group, while a standard deviation describes variation among individual measurements. A mean difference compares group averages. Insertion time is reported as 10.5 seconds for standard and 9.7 seconds for rotational insertion; the reported mean difference is -0.8 seconds, with a 95% confidence interval from -2.423 to 0.823. Oropharyngeal leak pressure is reported as 19.8 cmH2O and 20.5 cmH2O, respectively; the mean difference is 0.7 cmH2O, with a 95% confidence interval from -0.878 to 2.278. Both intervals include no mean difference.

The standard deviation is not the same as the standard error. In general, the standard deviation describes spread among participant measurements, while the standard error describes uncertainty in an estimated group mean. The registry lists group standard deviations and also posts standard errors for the continuous outcomes. It does not report further details about distributional checks, transformations, or model adjustments. Those analysis details are not reported in the registry record.

Why does over-dispersion matter?

In general, over-dispersion occurs when observed variation in count data exceeds what a statistical model assumes. If a model understates the variation, its standard errors may be too small and its confidence intervals too narrow. This is a general consideration for some count-data analyses, not a claim that over-dispersion occurred in this trial. The primary outcome is posted as a count of participants with an event, and the record does not describe a count model or report an over-dispersion assessment.

What can be inferred from the reporting?

The registry presents group summaries, effect estimates, confidence intervals, and unadjusted p-values for the posted comparisons. It does not provide reported analyses beyond these posted comparisons, and it does not describe an adjusted model, analysis population, or missing-data procedure. The estimate should therefore be read as the registry’s posted comparison, without assuming unreported modeling choices. The discrepancy flag is false, so there is no stated disagreement between the registry results and a recalculation that would require a separate precedence note.

11. Confidence Intervals and Precision

Precision is best judged from the range of values allowed by an estimate, rather than from the point estimate alone. For first-attempt success, the risk-difference estimate is 0.048, and its 95% confidence interval extends from -0.019 to 0.115. This interval includes no difference, a value favoring standard, and values favoring rotation. The result therefore leaves meaningful uncertainty about both the direction and size of the contrast.

The relative measures are also imprecise. The relative-risk interval runs from 0.980 to 1.129 around an estimate of 1.052. The odds-ratio interval runs from 0.479 to 40.55 around an estimate of 4.407. In general, confidence intervals for relative measures can be wide when event counts provide limited information, and an odds ratio can be particularly sensitive to sparse counts in one outcome category. The intervals indicate that the point estimates should not be read as exact or stable values.

The continuous-outcome intervals also include no difference: -2.423 to 0.823 seconds for insertion time and -0.878 to 2.278 cmH2O for oropharyngeal leak pressure. The blood-staining risk-difference interval is -0.029 to 0.089. These ranges indicate that the posted secondary comparisons are not highly precise. In general, a confidence interval is conditional on the statistical method and assumptions used to calculate it; the registry does not give complete details of those methods.

Precision is distinct from whether a result crosses a conventional significance threshold. A wide interval can reflect limited information even when its point estimate appears notable. Conversely, a narrow interval can estimate a small contrast precisely. Here, the primary interval itself communicates that the data do not pin down a single direction and magnitude. It does not establish equivalence, nor does it show that a meaningful difference is impossible.

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 justification. The registry’s planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each scenario asks how many participants per arm would be needed to detect a stated fraction of the observed effect. The scenarios are 100% of the observed effect, 75% of the observed effect, and 50% of the observed effect.

For these outcomes, the figures are participants per arm. The registry notes that time-to-event planning figures would instead give total events, using the Schoenfeld approach; there are no time-to-event outcomes among the posted measures. The 80% power column describes the planning count per arm associated with an 80% chance of detecting the assumed effect under the stated planning model, if its assumptions hold. The 90% power column gives the corresponding planning count for a 90% chance. These are design targets, not guarantees about what a future study would show.

Smaller effects require more participants to detect under the same planning assumptions. Thus, planning for 75% or 50% of the observed effect produces larger participant requirements than planning for the full observed effect. This is not observed power. It is a forward-looking illustration based on the observed effect estimate and stated assumptions, not a measure of the probability that this completed trial detected its effect.

The trial’s own original sample-size assumptions and justification are not reported in the registry record. The illustrative figures therefore should not be used to infer why the trial enrolled its recorded number of participants, or whether its original design was adequate for a different target effect.

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, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.937; treatment proportion p₁ = 0.985; average p̄ = 0.961.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.2749 = 0.5387.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.2727 = 0.2295.
4. n = (0.5387 + 0.2295)² / (0.0483)² = 252.6, rounded up to 253 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
p0 <- 0.936507936507937                          # control proportion
p1 <- 0.984848484848485                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^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 (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(3028896)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 253 (80% power), 338 (90% power)
 75% of observed effect: n per arm = 517 (80% power), 691 (90% power)
 50% of observed effect: n per arm = 1,310 (80% power), 1,753 (90% power)
power.prop.test: 252.6 
Simulated power at n = 253 per arm: 0.833 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-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 identifies first-attempt success as the primary outcome and lists three secondary outcomes. It reports unadjusted comparisons, but does not describe a multiplicity adjustment, testing hierarchy, or strategy for controlling the overall error rate across outcomes. Those plans are not reported in the registry record. As a result, the secondary p-values should not be treated as if they arose from a single isolated test with no other outcomes examined.

Multiplicity is a general statistical issue that arises when several hypotheses are tested. The more comparisons made, the greater the opportunity for chance variation to produce a seemingly notable result. Adjustment methods can address this issue, but may change the threshold or uncertainty used for interpretation. No such adjusted results are posted. This does not mean an adjustment was or was not used in an unreported analysis; it means the registry record does not establish one.

The record also does not describe missing-data handling, participant flow by outcome, or the analysis population used for each comparison. Although enrollment is 132, the primary endpoint denominators are 63 and 66, and the registry does not explain the relationship between these figures. It is therefore not possible from the posted information to determine why denominators differ from enrollment, whether outcomes were missing, or whether an intention-to-treat or per-protocol population was used. These details are not reported in the registry record.

Other statistical-plan details are also absent, including the original sample-size justification, allocation procedure, adjustment for baseline characteristics, and any interim analyses. They should not be inferred from the posted estimates. The registry lists triple masking but does not specify who was masked or how masking was maintained. These gaps limit the ability to assess the full analysis process and the prespecification of reported comparisons.

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 serious adverse-event summary reports 66 participants at risk in each group, with 0 serious events in the standard group and 0 in the rotational group. It also reports 0 deaths in each group. The registry lists no serious adverse-event terms. For the other adverse-event category, the summary reports 66 participants at risk and 0 affected in each group.

These figures describe the adverse-event information posted in the registry; they do not establish that no events of any kind occurred. The separate secondary outcome for blood staining reports its own participant counts and should not be conflated with the adverse-event categories. The registry does not provide further detail on event definitions, collection procedures, severity grading, or duration of safety follow-up. Those details are not reported in the registry record.

In general, zero reported events in a group does not prove that an event cannot occur. The number of participants observed and the completeness of event ascertainment matter when interpreting a zero count. The posted summary is therefore a record of reported serious and other adverse events, not a guarantee about safety outside the observations and definitions used in the trial.

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

The registry results show a higher point estimate for first-attempt success in the rotational group than in the standard group. The risk-difference estimate is 0.048, but its 95% confidence interval ranges from -0.019 to 0.115 and the unadjusted p-value is 0.155. This combination supports a cautious reading: the point estimate favors rotation, while the uncertainty remains compatible with no difference and with effects in either direction.

The results do not establish that the rotational technique is superior, nor do they establish that the techniques are equivalent. A finding that does not cross a statistical significance threshold is not proof of no effect. Equivalence requires a defined range of differences considered acceptably small and a design and analysis intended to test that question. Such a margin and analysis are not reported in the registry record.

The estimates also do not show the probability that a participant will succeed under either technique in every setting. The posted group proportions describe the observed trial groups. Generalization depends on how similar other participants, practitioners, and settings are to those represented in this record; participant characteristics and wider setting details are not reported in the registry record.

Secondary results add information about other recorded procedural outcomes, but their unadjusted analyses and uncertainty call for restraint. The adverse-event summary reports no serious events or deaths in either group, but this is limited to the events and follow-up represented in the registry. None of these statistical findings should be interpreted as medical advice. They describe the posted data and the uncertainty around the comparisons, rather than prescribing a technique or guaranteeing an outcome.

17. Why This Trial Matters Statistically

This trial illustrates why a randomized comparison should be read through both its effect estimate and its uncertainty. The first-attempt success proportions are high in both groups, and the estimated risk difference favors rotation. Yet the confidence interval also includes no difference and extends in the opposite direction. The point estimate alone would give an incomplete account of the evidence.

It also shows why effect scales matter. The absolute risk difference, relative risk, and odds ratio describe the same binary comparison in different ways, and their intervals communicate different degrees of uncertainty. A very large-looking odds ratio should not be interpreted in isolation when its interval is wide. Statistical reporting is most informative when measures are presented with intervals and explained in relation to the outcome.

The study further highlights the distinction between a primary endpoint and several secondary outcomes. Multiple unadjusted comparisons require caution, and the absence of a reported multiplicity plan limits claims based on secondary p-values. Planning illustrations based on the observed effects can help readers understand how target effect size relates to study size, but they cannot reveal the trial’s original design rationale or the probability that the completed study detected an effect.

Finally, the registry’s incomplete description of analysis populations, missing-data handling, and prespecified methods shows how reporting detail affects statistical interpretation. A numerical result can be read accurately while still recognizing that important design and analysis information is not reported. That distinction—between what the estimates say and what the record leaves unresolved—is central to responsible interpretation.

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.

The registry record leaves important trial and analysis details unspecified. It does not describe participant characteristics, eligibility criteria in the posted outcome information, the allocation procedure, or the identities of those masked. The recorded triple masking therefore does not reveal exactly how masking was implemented. These gaps limit assessment of how participants and procedures compare with other settings.

The record reports enrollment of 132, while the posted primary endpoint denominators are 63 and 66. It does not explain this difference or report participant flow, outcome-specific missingness, or the analysis population. Without those details, readers cannot assess whether the posted groups include all randomized participants or how unavailable outcome data were handled.

The primary confidence interval is compatible with effects in either direction, and the relative-effect intervals are broad. This limits precision. The secondary comparisons also have uncertainty, and no multiplicity strategy or adjusted analyses are reported. The registry gives no original sample-size rationale, so the planning illustrations based on observed effects cannot be treated as evidence of the study’s initial design assumptions.

All posted outcomes concern immediate procedural measurements: the primary outcome and two secondary outcomes are recorded at induction, while blood staining is assessed at post-op 1min. The registry does not report longer-term outcomes. It also does not provide detail on endpoint definitions, assessment methods, or the duration and procedures for adverse-event monitoring. These limitations are specific to the information available in the record and should not be filled in by assumption.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: 90° Rotation Technique for LMA FlexibleTM Insertion — NCT03028896.
• Registry record last updated 2022-02-09; status last verified 2022-02.
• Results first posted 2018-09-26.
• 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

NCT03028896 is a completed randomized, triple-masked, parallel-group trial sponsored by Seoul National University Bundang Hospital. The registry lists enrollment of 132 and compares standard with 90° rotational LMA FlexibleTM insertion. The primary outcome is first-attempt success at induction; the posted point estimate favors rotation, with a confidence interval that includes no difference.

Three secondary outcomes are posted: insertion time, oropharyngeal leak pressure, and blood staining. The serious adverse-event summary reports 0 serious events and 0 deaths in each group. The record does not report the original sample-size justification, detailed analysis populations, missing-data handling, or multiplicity plan. The findings are therefore best interpreted as estimates with the uncertainty and reporting limits.