Reducing Hypotensive Anesthesia Use With TXA During Orthognathic Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Reducing Hypotensive Anesthesia Use With TXA During Orthognathic Surgery (NCT05474027), a na phase 4 study. The primary outcome is Surgeon's Analysis of Surgical Field Visualization.

2. Clinical Question

3. Trial Design

This is a prospective, single-group study listed as Phase 4. The registry record lists the study as completed and records enrollment of 115. It identifies the sponsor as the University of Alabama at Birmingham. The recorded start date is 2022-11-11, and the primary completion date is 2025-11-11.

The single described group receives TXA and avoids deliberate hypotensive anesthesia. Allocation is listed as not applicable, and masking is listed as none. There is no separate control arm in the information recorded. Consequently, the study is not a randomized comparison, and its group cannot be treated as a like-for-like control for patients receiving a different anesthesia approach.

The primary endpoint is the surgeon’s assessment of surgical-field visualization, expressed as a mean and standard deviation on Fromme’s ordinal scale. The registry describes the assessment as occurring through the surgical procedure, and average of 2 hours. The record lists 3 outcome measures, but the other outcome descriptions are not reported in the registry record in the information available for this analysis.

A completed status indicates the recorded study status; it does not by itself establish that outcome results were posted. The record lists no analyses. It also does not report the study’s statistical analysis plan, a sample-size justification, or interim-analysis procedures. The absence of those details in the registry record should not be interpreted as evidence that the investigators did or did not carry out particular procedures.

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 Surgeon's Analysis of Surgical Field Visualization, measured over through surgical procedure, and average of 2 hours.

The primary endpoint is the surgeon’s rating of surgical-field visibility during orthognathic surgery, assessed with Fromme’s ordinal scale. The registry describes this as a scale ranging from 0, meaning no bleeding and a perfectly dry field, to 5, meaning severe bleeding that floods the field. The rating is based primarily on bleeding and the frequency of suction. The recorded summary measure is the mean, with standard deviation as the measure of dispersion.

This endpoint is used because visibility is a practical feature of operating conditions: bleeding and the need for suction can affect how clearly the surgeon sees the surgical field. In general, a rating scale converts these observations into ordered categories that can be recorded and summarized. It does not directly measure blood loss, organ injury, or the need for DHA; those are distinct outcomes.

There is an important interpretive distinction between the scale and the planned summary. The scale is ordinal: its values indicate an order from better to worse visibility, but equal numerical steps need not represent equal changes in the underlying surgical conditions. A mean and standard deviation summarize the ratings numerically, but the registry record does not report the observed mean, standard deviation, or distribution of ratings. The endpoint’s actual results and precision therefore cannot be assessed from the record described.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The available record supports a limited statistical interpretation: it describes a continuous summary of an ordinal rating in a single group, lists adverse-event counts, and does not report outcome analyses. The explanations below describe general statistical concepts and distinguish them from information recorded for this study.

What does a mean and standard deviation describe?

In general, a mean is a measure of the central value of observations. A standard deviation describes how spread out observations are around that mean. Together, they can help readers understand both the typical score and variability among ratings. For this study, the registry lists the primary measure as a mean and standard deviation, but does not report either observed value. There is consequently no numerical summary to interpret.

Fromme’s scale is described as ordinal: higher and lower ratings have an ordered meaning, but the gaps between adjacent ratings are not necessarily equal in practical terms. A mean treats the recorded values numerically, so it can be a concise summary, but it may not fully convey how ratings are distributed across categories. In general, category counts or a distribution can add context to a mean for an ordinal endpoint. Such a distribution is not reported in the registry record.

What would an uncertainty interval add?

In general, a confidence interval pairs an estimate with a range reflecting sampling uncertainty under a specified method. A narrow interval indicates greater precision than a wide interval, while neither width nor location alone establishes clinical importance. Interpretation also depends on the outcome scale and the question being asked. The registry record does not report an interval for the primary endpoint, nor an endpoint estimate from which to assess its precision.

A p-value is a measure calculated under a statistical model and a null hypothesis; it is not the probability that a hypothesis is true, nor a measure of how important an outcome is. No primary-outcome p-value or analysis is listed in the record. Since there is no reported comparison group, a conventional between-group treatment-effect test cannot be inferred from the design description. The record’s listing of 0 analyses does not establish whether analyses were conducted outside the registry.

Why does the design matter?

A single-group study can describe outcomes observed among participants receiving the study approach. It does not, by itself, provide a concurrent counterfactual: the outcome those same patients would have experienced under an alternative approach. In general, random allocation to comparable groups can help make treatment groups alike in expectation, supporting a causal comparison. This study is recorded as single-group, with allocation not applicable and no masking. A separate control group is not reported.

Accordingly, the design cannot isolate the effect of TXA from the effect of avoiding DHA or from other influences on visibility. Nor can the study description support a randomized estimate comparing TXA with a different strategy. This is a design limitation, not a finding about whether the approach changes the endpoint.

How should the planning illustrations be understood?

General sample-size illustrations are planning tools, not findings from a completed trial. The record’s assumptions describe two-sided significance level 0.05, equal allocation between two arms, a normal approximation, and effects defined as fractions of an observed effect. The illustrations are not the trial’s own design, which is listed as single-group. They must not be interpreted as observed power or as evidence that the study had a particular probability of detecting an effect.

For a planning calculation, the assumptions and target effect determine the resulting sample-size estimate. A planning illustration can help show how requirements would change under different hypothetical effects, but it cannot repair the absence of a comparator or establish the precision of an observed result. The registry record does not report a sample-size justification for this study. Any sample-size illustrations should therefore be kept separate from the study’s enrollment and from claims about what the trial was designed to establish.

What do the adverse-event counts show statistically?

Event counts are descriptive. A count of zero means that no event of that recorded category is reported for the group in the registry entry; it does not prove the true event risk is zero. In general, estimates of event risk and their precision depend on the observation process, follow-up, event definition, and denominator. The record reports at-risk counts and zero affected counts, but does not report additional detail needed to evaluate those aspects.

Over-dispersion is a general issue for count data when variability exceeds what a simple statistical model assumes. It can affect uncertainty estimates and model fit. No count model or adverse-event analysis is reported for this study, so it would be inappropriate to claim that over-dispersion was assessed or that a particular method was used. More broadly, the registry record does not report the statistical analysis plan, missing-data methods, or analysis populations. These omissions prevent a detailed appraisal of how outcomes were handled beyond the descriptive information recorded.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Patients Receiving Tranexamic Acid With Avoidance ")
n   <- c(115)
m   <- c(1.3)
sp  <- c(0.5)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Patients Receiving Tranexamic Acid With Avoidance   115  1.300  0.500  1.208  1.392

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 3 outcome measures, but the other outcome descriptions are not reported in the registry record in the information. It does not list any analyses. The statistical analysis plan, including whether a primary analysis was prespecified in detail or how multiple outcomes were to be handled, is not reported in the registry record.

Multiplicity arises when researchers make several statistical comparisons or tests. In general, testing multiple hypotheses can increase the chance of obtaining at least one result that appears notable by chance. Methods such as adjustment of significance thresholds or a prespecified hierarchy can address particular multiplicity concerns, but the record does not say whether any approach was planned or used. No adjusted or unadjusted result is reported, so there is no multiplicity-adjusted interpretation to make.

Missing-data handling is also not reported in the registry record. The record does not describe whether primary endpoint ratings were incomplete, how missing ratings would be treated, or whether sensitivity analyses were planned. It likewise does not report analysis populations, such as the set of participants included in the primary endpoint analysis. Enrollment alone does not establish how many participants contributed endpoint data, and no such number should be inferred.

These are limits on what can be evaluated from the registry record, not proof that particular procedures were omitted from the study itself. Without the analysis plan, missing-data details, and analysis populations, readers cannot assess the potential effects of selective outcome reporting, incomplete measurements, or analytic choices.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

For the group described as receiving TXA with avoidance of hypotensive anesthesia, the registry reports 0 serious adverse events among 115 at risk, 0 other adverse events among 115 at risk, and 0 deaths. These are the safety counts recorded for the study group. They should be read as registry-reported counts, not as proof that these events cannot occur.

A zero count is compatible with no events being observed in the recorded group, but it does not by itself quantify the underlying event risk or its precision. In general, interpretation also depends on how events were defined, how they were sought, and the period during which participants were monitored. Those details are not reported in the registry record. The listed at-risk figures do not provide information about the completeness or duration of follow-up.

The record also does not provide a separate control group for safety comparison or list serious adverse-event terms. Therefore, these counts do not establish whether the observed safety experience differs from another anesthesia or TXA approach. They are descriptive registry entries, and should not be used alone to infer comparative safety.

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

The record establishes that a prospective, single-group study of TXA with avoidance of deliberate hypotensive anesthesia was completed and that its intended primary outcome concerned surgeon-rated surgical-field visibility. It also records enrollment of 115 and reports zero serious adverse events, zero other adverse events, and zero deaths for the described group. These details describe the study and its recorded safety counts.

The record does not report the primary endpoint’s observed score or its variability. Consequently, it cannot show how the surgical fields were actually rated, how consistent ratings were, or how precise an estimate might be. It also does not report a numerical result for the stated question of whether TXA reduces the need for DHA. The study design contains no reported control group, so the record does not support a randomized comparison against another approach.

Even with a reported single-group endpoint result, an observed score would describe the participants studied rather than establish what would have happened under an alternative strategy. A causal comparison requires a suitable counterfactual; the registry design does not provide a like-for-like control. The absence of a reported statistical plan, analysis population, and missing-data methods adds uncertainty about how any outcome analysis would be interpreted.

Zero recorded adverse events should likewise be understood as a count, not a guarantee of safety or a comparison of risks. The registry does not report further detail about event ascertainment and follow-up. Overall, the available information describes the study question, design, planned primary measure, and event counts, but it does not provide the primary outcome result needed to judge the study’s findings.

14. Why This Trial Matters Statistically

This study matters statistically because its clinical question and its design do not line up with a direct comparative treatment-effect question. The question concerns whether TXA reduces the need for deliberate hypotensive anesthesia, while the recorded design is single-group and the described group receives TXA while avoiding DHA. Without a separate comparator, the study can describe its group but cannot directly estimate what would have happened under another approach.

The endpoint also illustrates a common measurement issue. Surgeons rate visibility on an ordered scale, while the registry identifies a mean and standard deviation as the summary. In general, summarizing ordinal ratings numerically may be useful, but the category distribution can matter because the distances between ratings are not guaranteed to be equivalent. The record does not report the observed summary or the distribution, so neither central tendency nor variability can be assessed.

Another statistical concern is the difference between a completed study and a reported result. Completion status and enrollment do not substitute for an endpoint estimate, uncertainty interval, or analysis description. The registry record lists no analyses, and it does not report missing-data methods or analysis populations. This limits reproducibility and appraisal of how the results were derived.

Finally, the safety counts show why zero events need careful interpretation. A zero count is informative as a description of what was recorded, but does not establish the absence of underlying risk or provide a comparison. Clear outcome reporting, event definitions, and follow-up details are important to understand what such counts can support.

15. Limitations

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

The primary limitation for interpreting this study is that the registry record does not report the primary endpoint result. Although it identifies the endpoint and its planned mean-and-standard-deviation summary, there is no reported mean, standard deviation, score distribution, or uncertainty estimate. The record therefore does not allow readers to assess surgical-field visibility outcomes or their precision.

The single-group design is a further limitation for the stated comparative question. Allocation is listed as not applicable, masking as none, and a separate comparator is not reported. The observations therefore cannot provide a randomized, like-for-like estimate of the effect of TXA or of avoiding DHA relative to another strategy.

Additional design and reporting details are not reported in the registry record, including eligibility criteria beyond the study’s orthognathic-surgery context, the statistical analysis plan, missing-data handling, analysis populations, and the definitions and follow-up procedures used for adverse events. The other outcome descriptions among the 3 listed measures are also not reported in the information available. These omissions restrict assessment of outcome completeness, analysis choices, and the scope of the safety counts.

The record lists the study as completed, but completion does not resolve these reporting gaps. Nor can the planning assumptions for hypothetical two-arm sample-size illustrations be treated as the study’s actual design or as evidence of observed power. The conclusions that can be drawn are therefore limited to the recorded study design, intended endpoint, enrollment, and adverse-event counts.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Reducing Hypotensive Anesthesia Use With TXA During Orthognathic Surgery — NCT05474027.
• Registry record last updated 2026-05-27; status last verified 2025-12.
• Results first posted 2026-05-27.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

The registry record describes a completed, prospective, Phase 4, single-group study of TXA with avoidance of deliberate hypotensive anesthesia during orthognathic surgery. It records enrollment of 115, no masking, and allocation as not applicable. The sponsor is the University of Alabama at Birmingham.

The primary endpoint is the surgeon’s assessment of surgical-field visualization using Fromme’s ordinal scale, summarized as a mean and standard deviation. The primary endpoint result is not reported in the registry record. The record lists 3 outcome measures and no analyses.

For the described group, the registry reports 0 serious adverse events, 0 other adverse events, and 0 deaths. The study is not a randomized comparison and has no reported like-for-like control group. The statistical analysis plan, missing-data procedures, and analysis populations are not reported in the registry record.