Use of Baxter Animated Retching Faces (BARF) Scale to Measure Nausea in Children Who Speak Spanish: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Use of Baxter Animated Retching Faces (BARF) Scale to Measure Nausea in Children Who Speak Spanish (NCT02007109), a registered phase not stated study. The primary outcome is Incidence of Postoperative Nausea and/or Vomiting (PONV) in the Postanesthesia Care Unit (PACU).

2. Clinical Question

The motivating issue is that nausea is subjective and difficult to quantify, particularly in children. The registry summary contrasts the established use of VAS in adults with uncertainty about its reliability in young children. The study therefore concerns measurement, rather than a comparison of treatments. The available record identifies the scales and the intended clinical context, but leaves key elements of the measurement question unresolved: how the scales were compared analytically, what criterion was used to judge reliability, and what results were obtained. Those details are not reported in the registry record.

3. Trial Design

The record identifies this as a completed study sponsored by Baylor College of Medicine, with enrollment of 193. It lists postoperative nausea and vomiting as the condition and gives the title as a study of the BARF scale for measuring nausea in children who speak Spanish. The listed arm is named “Nausea Measurement by VAS and BARF.” Its description says participants would be asked to rate nausea on both scales. The detailed script in the registry entry is incomplete, so the full administration procedure is not reported in the registry record.

This is not described as a randomized treatment trial. The registry record explicitly notes that allocation is not stated and that the arms are not a like-for-like control comparison. The actual allocation process, number of enrolled arms, and whether any participants received only one scale are not reported in the registry record. The design should therefore not be interpreted as establishing a randomized comparison between measurement strategies.

The primary outcome is tied to the post-anesthesia care unit (PACU). Participants were to rate pain and nausea upon waking, just before and 30-60 mins after analgesic or antiemetic therapy, and upon discharge from PACU. The record also lists two secondary outcomes: subjects who experienced nausea and/or vomiting after discharge (PDNV), and whether pain and/or nausea/vomiting rescue was needed. It reports 3 outcome measures overall, but does not give numerical results for them in the information available.

The registry gives a start date of 2014-01, a primary completion date of 2018-03-08, and completed status. The planned sample-size assumptions describe an illustration based on an observed effect, with two-sided significance level 0.05, equal allocation between two arms, and a normal approximation. Those are planning assumptions, not evidence about the actual allocation or an observed treatment effect. The trial’s own sample-size justification is not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Some PACU data is partial due to subjects being uncooperative at times (n=5) or being asleep until just before discharge (n=2)

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 Incidence of Postoperative Nausea and/or Vomiting (PONV) in the Postanesthesia Care Unit (PACU), measured over When awake and responding to commands in the post-anesthesia care unit (PACU).

The registered primary endpoint is titled incidence of postoperative nausea and/or vomiting in the PACU. The description says participants rated pain and nausea at specified PACU time points: upon waking, just before and 30-60 mins after receiving analgesic or antiemetic therapy, and upon discharge. The rating scales are described as ranging from 0 to 10, with lower scores indicating no pain or nausea. The endpoint entry gives the parameter as a mean and the dispersion as full range.

These ratings are relevant because nausea is subjective: a structured scale can turn a participant’s reported experience into an ordered numerical measure that can be summarized and compared. A mean describes the average rating, while a full range describes the span from the lowest to the highest recorded value. Those summaries answer different questions; a mean alone does not show how widely individual ratings vary.

There is an important distinction between the endpoint title and its description. The title refers to incidence of PONV, which ordinarily implies whether an event occurred, while the description focuses on scale ratings of pain and nausea over time. The registry does not explain whether the primary analysis concerned event occurrence, average ratings, or both. Nor does it report a numerical endpoint result in the information available. Accordingly, the endpoint’s intended role is apparent as PACU symptom assessment, but its exact analysis definition is not reported in the registry record.

The registry notes that some PACU data are partial because participants were uncooperative at times (n=5) or asleep until just before discharge (n=2). This matters because ratings at different time points may not be available for every participant. The handling of those partial records is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a measurement study in which participants were asked to rate nausea using VAS and BARF. It does not provide the statistical analysis plan or list any analyses. The concepts below explain how the registered endpoint and planning assumptions are generally interpreted; they do not imply that a particular method was used in this study.

What does a mean rating convey?

In general, a mean is the arithmetic average of recorded values. For a symptom scale, it can provide a compact description of the central level of ratings across participants or assessments. It does not show whether most participants gave similar ratings or whether the average combines very different experiences. The registry identifies the primary parameter as a mean and the dispersion as full range, but the numerical mean and range are not reported in the available record.

A full range describes the lowest and highest observations. It can show the total spread of recorded values, but it is sensitive to extreme observations and does not show how commonly values near either endpoint occurred. A range should therefore be interpreted alongside other summaries when those are available. The registry does not specify whether additional summaries were used.

How should a symptom scale be understood?

General statistical interpretation distinguishes a measurement instrument from the construct it is intended to measure. A rating scale gives a structured response format for a subjective experience; it does not automatically demonstrate that responses are reliable or that they represent nausea accurately. Assessing reliability could involve checking whether repeated measurements are consistent under appropriate conditions. Assessing validity could involve examining whether ratings behave as expected in relation to a relevant criterion or other measures. The registry does not state which such assessment was prespecified or performed.

The endpoint description says lower scores indicate no pain or nausea and gives a scale range of 0 to 10. That establishes the stated orientation of the scale. It does not report the observed scores, whether all response options were used, or whether the scale behaved similarly across participants. Although the study title emphasizes children who speak Spanish, the registry information available does not describe translation procedures, language testing, or subgroup analyses. Those methods are not reported in the registry record.

Why does endpoint definition matter?

Incidence and intensity are different statistical targets. Incidence concerns whether a defined event occurred, whereas a rating mean concerns the level of a symptom on a scale. A single participant may have a symptom event and also have a severity rating, but the two outcomes are not interchangeable. Here, the primary endpoint title refers to incidence of postoperative nausea and/or vomiting, while the endpoint description refers to pain and nausea ratings over several PACU time points. The registry does not clarify how this difference was resolved in analysis. Without a precise endpoint definition, a numerical result could be difficult to interpret even if one were reported.

What does a confidence interval add?

In general, a confidence interval expresses the uncertainty around an estimated quantity under the assumptions of the statistical method. A narrower interval indicates greater precision for that estimate, while a wider interval indicates less precision. An interval does not establish that a measurement is valid, and it does not repair an unclear endpoint definition. No confidence interval is reported for the primary outcome in the registry information available.

Likewise, a significance test addresses whether data are compatible with a specified null hypothesis under model assumptions; it does not measure the size or practical importance of an effect. The registry does not report a test statistic or p-value for the endpoint. The two-sided significance level of 0.05 appears among the sample-size planning assumptions, not as a reported result of a completed analysis.

How should planning illustrations be read?

The registry describes sample-size planning illustrations based on the observed effect. The stated assumptions include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect set as a stated fraction of the observed effect. These figures are planning illustrations, not observed power and not a report of the trial’s actual enrollment allocation. They show how sample-size requirements depend on the chosen target effect and statistical assumptions; they do not demonstrate that the trial achieved a particular level of power. The study’s own sample-size justification is not reported in the registry record.

In general, a normal approximation uses a mathematical model that treats an estimate, or its sampling distribution, as approximately normal. The suitability of that approximation depends on the outcome and data structure. The registry does not report enough analysis detail to assess whether it was used for the primary outcome, beyond its stated role in the planning illustration. It also does not report whether repeated ratings within a participant were handled with a repeated-measures model or another method.

What can be inferred from the analysis record?

The registry lists 3 outcome measures and 0 analyses. That is a record of what is listed, not proof that no analysis was conducted outside the registry. The information available does not identify an analysis population, missing-data method, model, covariate adjustment, or approach to multiple outcomes. These omissions prevent replication of a statistical analysis from the registry entry alone. They also mean that any claim about comparative scale performance would require results and methods beyond those reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 3 outcome measures: the primary PACU outcome and two secondary outcomes concerning nausea and/or vomiting after discharge and rescue for pain and/or nausea/vomiting. Considering multiple outcomes can raise a multiplicity issue. In general, when several outcomes or comparisons are tested, the chance of at least one apparently notable result can increase if no adjustment or prespecified hierarchy is used. The registry does not report a multiplicity strategy, endpoint hierarchy beyond the primary/secondary labels, or a set of planned comparisons. The 0 analyses listed do not identify which outcomes were analyzed or whether any adjustment was made.

Missingness is explicitly acknowledged for some PACU observations: data are partial because participants were uncooperative at times (n=5) or asleep until just before discharge (n=2). The record does not say which time points were missing for these participants, whether the reasons overlapped, or how many ratings were available at each assessment. No totals should be inferred from these separate descriptions.

In general, missing-data handling matters because analyses based only on available observations can be biased if the chance that a measurement is missing is related to the unobserved rating or to participant characteristics. Possible approaches depend on the amount and pattern of missingness, the outcome, and assumptions about why data are absent. The registry does not report a complete-case approach, imputation method, sensitivity analysis, or other missing-data procedure.

The analysis population is also not described. Enrollment of 193 does not establish that all enrolled participants contributed to each endpoint, particularly given the partial PACU data. The record does not report whether eligibility, consent, or post-discharge follow-up affected the analysis population. These details are not reported in the registry record.

11. 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 adverse-event entry lists 193 participants at risk for the reported group. It records 0 serious events, 0 other events, and 0 deaths. No serious adverse-event terms are listed. These figures mean that the registry entry records no events in those categories for the group; they should not be read as proof that no symptoms or other events occurred outside the defined reporting and observation process.

The study concerns nausea measurement, and its listed outcomes include nausea, vomiting, and rescue needs. Those outcomes are not interchangeable with serious adverse events. A symptom outcome can be measured without meeting the definition of a serious event, and the adverse-event summary does not replace the efficacy or measurement outcomes. The registry information available does not explain the event-collection procedures, observation period for adverse events, or criteria used to classify seriousness.

The zero counts should also be interpreted in the context of the reported risk set and available follow-up. The entry gives 193 at risk, but does not report further details about exposure duration, completeness of adverse-event follow-up, or whether all participants were observed for the same period. The record therefore supports a narrow statement about what was recorded in the adverse-event fields, not a broader conclusion about safety beyond that reporting context.

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

The study’s central subject is how nausea is measured in children who speak Spanish. The record identifies VAS and BARF as the measurement approaches and describes ratings in the PACU. It also names post-discharge nausea and vomiting and rescue needs as secondary outcomes. These details show the clinical and measurement context, but they do not establish which scale performed better.

No numerical result for the primary endpoint or secondary outcomes is reported in the information available. There is no reported scale-specific estimate, uncertainty interval, or statistical comparison from which to judge the magnitude or precision of any observed difference. The registry record also does not describe a validation criterion, reliability statistic, or analysis linking the scales. Conclusions about validity, reliability, agreement, or responsiveness would therefore go beyond the posted results.

The title and endpoint description are not fully aligned: the title refers to incidence of PONV, while the description emphasizes ratings of pain and nausea. That distinction matters because event occurrence and symptom intensity answer different questions. The record does not explain the endpoint definition used for analysis. Likewise, the record does not state how the scale administration was standardized beyond saying that participants were asked to rate nausea on both scales.

The nonrandomized status and unstated allocation mean that the study should not be read as a randomized treatment comparison. The registry explicitly warns that the arms are not a like-for-like control comparison. The sample-size illustrations are based on planning assumptions and are not observed power. They do not establish that the study was adequately powered for a particular analysis or that a result would be precise.

What the record does support is a description of a completed study, enrollment of 193 participants, the measurement scales named, the PACU assessment schedule, and the presence of partial PACU data for some participants. What it does not support is a claim that BARF is reliable, valid, superior, or equivalent to VAS in this study. Those conclusions require outcome results and analysis details that are not reported in the registry record.

13. Why This Trial Matters Statistically

Measuring a subjective symptom is a statistical problem as well as a clinical one. Nausea cannot be observed directly in the same way as a laboratory value; it must be elicited and represented through participant responses. A scale can make those responses easier to record and summarize, but its usefulness depends on whether participants understand it and whether its scores represent the symptom of interest in the intended population.

This study is notable for focusing on children who speak Spanish and naming both VAS and BARF as nausea measurement approaches. The registry summary identifies a broader challenge: methods used in adults may not be reliable in young children. That concern makes the definition, administration, and evaluation of a pediatric symptom scale important. The registry record, however, does not report enough methods or results to judge how the study addressed those measurement questions.

The entry also illustrates why endpoint language deserves close attention. “Incidence” suggests whether nausea or vomiting occurred, while a mean rating describes symptom intensity. Both can be useful, but they are different estimands and call for different interpretations. A clear endpoint definition is essential for choosing a statistical summary and for explaining what an analysis can answer.

Finally, the record identifies incomplete PACU data and does not report how those data were handled. Missing observations can affect the interpretation of repeated symptom ratings, particularly when reasons for missingness include being uncooperative or asleep at an assessment. Reporting the pattern of missingness and the analysis approach helps readers evaluate the robustness of measurement conclusions. The trial matters statistically because it raises these central issues of measurement, endpoint definition, and incomplete repeated observations, even though the registry record does not provide the results needed to resolve them.

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 information available has several trial-specific limitations. The registry title emphasizes children who speak Spanish, but the participant characteristics, age distribution, language eligibility requirements, and recruitment setting are not reported in the registry record. The record therefore does not show how broadly the enrolled group represents children who speak Spanish or other pediatric populations.

The arm description says participants would rate nausea using both VAS and BARF, but its detailed script is incomplete. The sequence of scale administration, the exact instructions, training procedures, and whether scale order was varied are not reported in the registry record. These details could matter in a measurement study because comprehension, presentation, or order may influence responses.

The primary endpoint title and description differ in emphasis. Incidence of PONV is named, while the description specifies symptom ratings at several time points and identifies the mean and full range. The analysis definition and the relationship between event occurrence and rating summaries are not reported in the registry record. This makes it difficult to determine precisely what the primary analysis was intended to estimate.

The record does not report a specific validation criterion, a reliability analysis, an agreement analysis, or numerical results. It also lists 0 analyses. Thus, the posted information does not allow readers to assess scale performance or reproduce a comparison. The nonrandomized nature and unstated allocation further mean that the listed arms should not be treated as equivalent groups in a controlled comparison.

Partial PACU data are acknowledged for participants who were uncooperative or asleep, but the affected time points, missing-data method, and sensitivity analyses are not reported. The completeness of post-discharge follow-up and the analysis population are likewise not described. Finally, the registry gives a planning illustration based on an observed effect, but the study’s own sample-size justification is not reported. These limitations concern the documentation available in the registry record and should not be taken as proof that the unreported procedures were not performed.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Use of Baxter Animated Retching Faces (BARF) Scale to Measure Nausea in Children Who Speak Spanish — NCT02007109.
• Registry record last updated 2020-03-30; status last verified 2020-03.
• Results first posted 2020-03-30.
• 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

NCT02007109 is a completed study sponsored by Baylor College of Medicine, titled “Use of Baxter Animated Retching Faces (BARF) Scale to Measure Nausea in Children Who Speak Spanish.” The registry lists postoperative nausea and vomiting as the condition and reports enrollment of 193. The listed measurement approach asks participants to rate nausea using both VAS and BARF.

The primary outcome is titled incidence of PONV in the PACU. Its description gives pain and nausea rating times and a scale range of 0 to 10, but does not provide numerical outcome results. Secondary outcomes concern post-discharge nausea and/or vomiting and rescue needs. The record notes partial PACU data for participants who were uncooperative at times (n=5) or asleep until just before discharge (n=2).

Allocation is not stated, the record cautions that arms are not a like-for-like control comparison, and 0 analyses are listed. Numerical scale-comparison results, analysis methods, and the trial’s own sample-size justification are not reported in the registry record.