Effect of Intra-cuff Lidocaine and Tetracaine on Tracheal Tube-induced Emergence Phenomena: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effect of Intra-cuff Lidocaine and Tetracaine on Tracheal Tube-induced Emergence Phenomena (NCT00798018), a randomized na study. The primary outcome is Visual Analogue Scale(0-100mm) by the Subject..

2. Clinical Question

The study summary frames the investigation as an evaluation of lidocaine cuff inflation in non-nitrous oxide anesthesia and a comparison of tetracaine with lidocaine. The record does not provide a complete description of anesthesia procedures or confirm the anesthetic regimen used for each participant. Accordingly, that summary states the investigators’ motivation, but does not establish the clinical context in enough detail to interpret outcome differences by anesthetic regimen.

3. Trial Design

The registry identifies this as a randomized, double-masked, parallel trial. Randomization is intended, in general, to make treatment groups comparable on average at the start of a study, while masking can reduce the influence of treatment knowledge on care or outcome assessment. The record does not report the sequence-generation method, how allocation was concealed, which parties were masked, or how masking was maintained. Those details are therefore not reported in the registry record.

The four cuff inflation descriptions are air, normal saline, 2% lidocaine, and 1% tetracaine. The listed intervention terms also include placebo and N.S. The record does not explain whether those terms correspond to particular arm labels beyond the arm descriptions, or provide further procedural details. The parallel model indicates that participants were assigned to a group rather than described as crossing between treatments; the timing and process of treatment assignment are not reported in the registry record.

Enrollment is listed as 100. The registry lists the phase as NA and the status as completed. The sponsor is Sichuan University. The record gives the study start as 2008-10 and primary completion as 2009-02. It does not report the number of participants who completed follow-up, the numbers analyzed for the primary outcome, or reasons for withdrawal or exclusion.

The primary measure is a subject-rated sore-throat visual analogue scale at 6 hours, 12 hours, 24 hours, and 48 hours after extubation. The registry does not report a statistical analysis plan, a prespecified primary contrast, or a method for handling repeated outcome assessments. It also does not report whether additional outcomes were collected beyond the one registered outcome measure.

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 Visual Analogue Scale(0-100mm) by the Subject., measured over 6 hours, 12 hours, 24 hours, 48 hours after extubation.

The primary endpoint is the participant’s rating of post-intubation sore throat on a visual analogue scale, recorded in millimeters. The record describes a line with 0 meaning no pain and 100 meaning the worst pain that can be imagined; the participant marks the point that corresponds to the pain they feel. This is a subjective measure: it records the participant’s own experience rather than an observer’s rating of visible signs.

A visual analogue scale is used to represent symptom intensity along a continuous range. In general, this format can distinguish gradations of a symptom that a simple present-or-absent measure would not capture. It is relevant to a sore-throat question because the symptom is experienced by the participant, and the participant’s rating is the direct measure of that experience. The record describes the scale as a recognized standard tool for pain rating.

Scores are scheduled at 6 hours, 12 hours, 24 hours, and 48 hours after extubation. Repeated assessments can describe how symptom ratings vary over the stated follow-up times, but they also require clarity about which time point or summary is primary and how comparisons across times are handled. That analysis detail is not reported in the registry record. Numerical scores, measures of variability, and comparisons among groups are also not reported in the registry record. The endpoint’s definition is available, but its observed values and precision cannot be assessed from the registry entry.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a randomized, double-masked, parallel design and a continuous primary outcome summarized as a mean with standard deviation. It does not report the analysis actually used for the primary endpoint. The concepts below are general explanations of ways such data can be analyzed; they should not be read as a description of undocumented trial procedures.

What does a mean summarize?

For a continuous measure such as a visual analogue scale, a group mean describes the arithmetic average of recorded scores. It gives a central summary, but it does not show how scores are distributed or whether individual participants had similar experiences. The standard deviation describes the spread of scores around the mean. It is not the same as the uncertainty in the estimated mean: the latter also depends on the amount of information available and is commonly represented with a confidence interval. The registry record gives the endpoint’s planned summary type, but reports no outcome means, standard deviations, or confidence intervals.

What would a treatment contrast represent?

In general, an unadjusted contrast between group means describes the difference in average scores between the groups being compared. Its interpretation depends on which groups are selected, the time point used, and whether the comparison follows the randomized assignment. An adjusted contrast would also depend on the covariates and model specified. The registry record does not report a primary contrast, any adjustment variables, or an estimation method. Thus, no particular contrast or adjusted analysis can be attributed to this trial from the record.

Why does randomization matter to analysis?

As a general principle, random assignment can help balance both measured and unmeasured baseline characteristics across groups over repeated assignments. It does not guarantee exact balance in a particular trial, and it does not replace clear reporting of participant flow, outcome availability, or analysis populations. Analysis by assigned group is often used to preserve the comparison created by randomization, while other analysis populations may answer different questions. The registry does not describe the analysis population or say how participants with missing outcome measurements were handled.

How should repeated assessments be considered?

The same primary outcome is scheduled at 6 hours, 12 hours, 24 hours, and 48 hours after extubation. In general, measurements from the same participant are related, so treating every recorded value as independent can misrepresent uncertainty. A repeated-measures model can account for within-participant association, while separate analyses at each time point answer a set of distinct questions. A prespecified summary or primary time point can also focus interpretation. The registry does not state which approach was used, whether a treatment-by-time pattern was assessed, or how within-participant correlation was handled.

Why can over-dispersion matter?

General note: over-dispersion occurs when the observed variability is greater than a statistical model assumes. It is especially relevant to count outcomes when a model expects a particular mean-variance relationship. The registered primary endpoint is a continuous pain score summarized by its mean and standard deviation, not a count endpoint. The registry does not report a model or diagnostic assessment for the score, so there is no basis to say over-dispersion was assessed or affected this analysis. For continuous outcomes, the broader lesson is to check whether a model’s distributional and variance assumptions are reasonable rather than assume that a chosen model fits automatically.

What does multiplicity mean for several times and groups?

General note: multiplicity arises when several statistical tests or estimates are considered together. The more opportunities there are to identify an apparently notable result, the more important it is to specify which comparisons are confirmatory and how interpretation will account for the collection of tests. This trial has four described cuff inflation groups and four scheduled outcome times, but the registry does not provide a testing hierarchy, multiplicity adjustment, or prespecified primary contrast. The number of possible comparisons should not be mistaken for evidence that each was tested, and no test results are reported.

How should planning calculations be read?

The planning assumptions describe an illustration based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a stated fraction of the observed effect. Such calculations are planning illustrations, not observed power and not outcomes from the trial. The registry does not report a sample-size justification for the original design, nor does it report the observed primary effect needed to assess such an illustration. The sample-size assumptions therefore do not supply evidence about the trial’s findings or the precision actually achieved.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome is scheduled at 6 hours, 12 hours, 24 hours, and 48 hours after extubation, and the record describes four cuff inflation groups. Multiple times and possible group contrasts raise questions about which comparison was primary and how any additional comparisons were to be interpreted. The registry record does not report a multiplicity strategy, a testing hierarchy, or a designated primary time point. It does not report whether the analyses were planned before results were examined.

The registry lists one outcome measure and zero analyses. Numerical primary-outcome results and analysis populations are not reported in the registry record. The record does not state how many participants contributed observations at each time, how missing scores were handled, or whether an analysis used all randomized participants, only those with observed outcomes, or another defined population. Reasons for missing assessments, withdrawals, and exclusions are not reported in the registry record.

These omissions limit interpretation independently of the numerical size of any result. Missing observations can affect both the estimate and its uncertainty when the availability of an outcome is related to participant characteristics or symptom severity. In general, a complete account describes the amount and pattern of missing data, the analysis population, and the assumptions used to handle unavailable measurements. No such detail is reported in the registry record, so it is not possible to assess those assumptions or the robustness of an analysis.

The record also does not report a statistical analysis plan or distinguish confirmatory from exploratory comparisons. Without that information, readers cannot determine how the multiple assessment times were accounted for or whether any reported comparison would have been prespecified. Since no numerical analyses are reported, there are no statistical findings for which a multiplicity adjustment or missing-data method can be evaluated.

11. 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 1% reporting threshold.

The safety listing gives 25 at risk in each of the Air Alone, Normal Saline, Lidocaine, and Tetracaine groups. It records 0 serious events affected and 0 other events affected in each group. These are the figures entered in the registry; they are not a substitute for the primary outcome, which is the subject-rated sore-throat scale.

A zero recorded count means that the registry entry lists no affected participants for that event category. It does not establish that no event could have occurred, and it does not show how events were defined, collected, or verified. The period during which adverse events were monitored and the method of ascertainment are not reported in the registry record. The record lists no serious adverse event terms. Death counts are not reported in the registry record.

These safety figures should be read as descriptive registry entries rather than as a detailed safety analysis. The record does not provide event narratives, severity grading beyond the serious-versus-other categories, relatedness to cuff inflation, or statistical comparisons among groups. With no such information and no primary outcome results, the safety listing cannot explain the balance of benefits and harms or establish comparative safety.

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

The registry record establishes that the trial was randomized, double-masked, and parallel, and that it compared cuff inflation with 2% lidocaine or 1% tetracaine against air or normal saline descriptions. It defines a participant-rated sore-throat outcome on a 0-to-100 mm visual analogue scale and schedules assessment at 6 hours, 12 hours, 24 hours, and 48 hours after extubation. These details clarify what was investigated and how the primary symptom was intended to be measured.

The record does not report the numerical outcome results or any analyses. It therefore does not establish whether the average score differed across groups, the direction or size of a difference, or how precisely an effect was estimated. The absence of reported results is not evidence that groups had identical outcomes, and it is not evidence that one cuff inflation approach produced a better or worse score. No conclusion about the trial’s primary question can be drawn from the registered outcome definition alone.

The record also does not provide enough information to assess how outcome measurements were handled across time, how missing scores were treated, or which comparisons were prespecified. These are relevant to understanding both the reliability and interpretation of any analysis, but they are not reported in the registry record. The listed adverse event figures are limited to recorded counts and do not fill the gap in primary-outcome results.

In general, a trial result is best interpreted using an effect estimate, its uncertainty, the analysis context, and the outcome’s clinical meaning together. A statistical comparison is not by itself a measure of clinical importance, and the registry entry does not provide the estimates needed to make either assessment. The appropriate reading is therefore bounded: the record describes a completed trial design and a symptom endpoint, but does not report findings that permit a conclusion about the comparative scores.

13. Why This Trial Matters Statistically

This trial raises a useful statistical issue: a clearly defined symptom measure can still be difficult to interpret when its results and analysis details are absent. The visual analogue scale gives a direct, participant-rated measure of sore-throat intensity, while the scheduled assessments cover several times after extubation. Those repeated assessments create an analysis question about whether the emphasis is on a particular time, a trajectory, or a summary across times. The registry record does not specify the answer.

The design also includes four cuff inflation descriptions. A randomized, double-masked, parallel structure is relevant to how comparisons might be made, but a reader still needs to know the primary contrast, the analysis population, and how missing observations and repeated measurements were handled. The registry does not report those details or numerical analyses. This shows why design labels alone cannot substitute for transparent statistical reporting.

The primary outcome is measured on a continuous scale and is described as a mean with standard deviation. In general, reporting an effect estimate together with uncertainty would allow readers to distinguish the estimated magnitude from its precision. Neither is reported in the registry record. The safety entries likewise illustrate the difference between a recorded count and a complete account of event definitions, collection, and interpretation.

The statistical importance of this record is therefore not an unreported treatment effect, but the separation between an endpoint’s definition and evidence about its results. The design and measurement details identify the intended question; the missing outcome estimates, analysis choices, and data-completeness information prevent an assessment of what the trial found.

14. Limitations

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

The main limitation for interpreting this specific trial from the registry record is the absence of numerical primary-outcome results. Although the endpoint, unit, summary type, and follow-up times are stated, the record does not report group means, standard deviations, treatment contrasts, confidence intervals, or test results. The observed size and precision of any differences therefore cannot be assessed.

The primary outcome has several scheduled assessment times, but the registry does not report which time point or summary was primary for analysis, how repeated measurements were modeled, or how comparisons across times and groups were handled. A statistical analysis plan, testing hierarchy, and multiplicity approach are not reported in the registry record. This leaves the intended interpretation of multiple possible comparisons unclear.

Participant flow and analysis populations are not reported in the registry record. The entry does not state how many participants had outcome data at each time, how missing scores were handled, or the reasons for missingness, withdrawals, or exclusions. It also does not report detailed eligibility criteria, baseline characteristics, randomization procedures, allocation concealment, or which parties were masked. These omissions limit assessment of group comparability, implementation, and potential bias.

The safety listing records zero affected for serious and other event categories in each group, but does not describe event definitions, ascertainment, monitoring periods, severity details, or relatedness. Death counts are not reported in the registry record. Finally, the record does not provide full details of the anesthesia regimen or a sample-size justification for the trial. Each of these gaps narrows what can be concluded from the registered information, without implying that an unreported procedure or result was absent from the conduct of the study.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effect of Intra-cuff Lidocaine and Tetracaine on Tracheal Tube-induced Emergence Phenomena — NCT00798018.
• Registry record last updated 2009-12-18; status last verified 2009-11.
• Results first posted 2009-12-18.
• 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.

18. Record Summary

The registry describes a completed randomized, double-masked, parallel trial sponsored by Sichuan University, with enrollment listed as 100. The study compares cuff inflation descriptions involving air, normal saline, 2% lidocaine, and 1% tetracaine. Its primary outcome is a participant-rated visual analogue scale for post-intubation sore throat, measured in millimeters at 6 hours, 12 hours, 24 hours, and 48 hours after extubation.

The record lists one outcome measure and zero analyses. Numerical primary-outcome results, confidence intervals, analysis populations, missing-data methods, and a multiplicity plan are not reported in the registry record. Safety entries list zero serious and zero other events affected in each group, with 25 at risk in each group; event collection details and death counts are not reported. The record supports describing the trial question and outcome schedule, but not a conclusion about comparative sore-throat scores.