Clinical Use of Baxter Animated Retching Faces (BARF) Scale in Children: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Use of Baxter Animated Retching Faces (BARF) Scale in Children (NCT02421952), a registered phase not stated study. The primary outcome is Number of Patients With Nausea, Emesis, Severe Nausea, Severe Emesis and Number Receiving Rescue Antiemetics in the Post-Anesthetic Care Unit (PACU).

2. Clinical Question

The clinical context is a measurement problem: nausea is subjective, while emetic episodes are observable. The registry summary notes that episode counts correlate poorly with the subjective symptom of nausea. It also states that the visual analogue scale is accurate in adults but has not been shown to be reliable in young children. Against that background, the study’s focus is assessment in children, including a pictorial nausea scale.

The registered measurements include pain as well as nausea. The scale descriptions explain how higher scores indicate more intense pain or nausea, but the registry record does not report a primary analysis comparing scale scores or establish that one scale is superior. The outcome definition instead centers on participant counts in the PACU. Thus the question should be read as one about symptom assessment and recorded outcome frequencies, not as a treatment-effect question.

3. Trial Design

The registry record describes a completed study sponsored by Baylor College of Medicine. Its title is “Clinical Use of Baxter Animated Retching Faces (BARF) Scale in Children.” The record lists an enrollment of 208, a start date of 2013-04, primary completion on 2018-03-08, and status COMPLETED.

The design is recorded as a single cohort. All subjects were asked to assess pain and nausea using the visual analogue scales, the modified faces scale, and the BARF scale in preoperative and postoperative areas. This is not a randomized comparison of treatments, and the registry record does not describe allocation to different groups. The scales are measurements applied to the cohort rather than distinct therapies.

The primary outcome concerns participants with nausea, emesis, severe nausea, severe emesis, and receipt of rescue antiemetics in the post-anesthesia care unit. Its timeframe is when participants were awake and responding to commands in the PACU. The secondary outcomes concern post-discharge nausea, emesis, severe symptoms and rescue antiemetics among subjects who returned the diary, and age-related ability to use the BARF scale.

The registry record does not report the study’s detailed eligibility criteria, the age range, the timing of each assessment beyond the stated areas and primary timeframe, or the operational thresholds for severe nausea and severe emesis. It also does not report the number of participants contributing data to each outcome. Those omissions limit how specifically the study population and measurement procedures can be reconstructed from 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: Patients with severe nausea were included in the number with any nausea. Patients with severe emesis were included in the number with any emesis. Because some patients had both nausea and vomiting, the sum of the number with nausea and the number with emesis will not equal those with either nausea or emesis.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: 208 subjects screened for the ability to use VAS and Pictorial Scales. 16 subjects excluded from PACU and Post-discharge analysis for failed seriation task, being uncooperative during baseline assessment, or having their surgery cancelled after consent was obtained.

6. Primary Endpoint

The registry lists the primary outcome as Number of Patients With Nausea, Emesis, Severe Nausea, Severe Emesis and Number Receiving Rescue Antiemetics in the Post-Anesthetic Care Unit (PACU), measured over When awake and responding to commands in the post-anesthesia care unit (PACU).

The primary endpoint counts participants with nausea, emesis, severe nausea, severe emesis, and receipt of rescue antiemetics in the PACU. The specified assessment timeframe is when participants were awake and responding to commands. The unit is participants, so the endpoint is a set of counts rather than a mean scale score or a time-to-event measure.

This outcome is relevant to the study’s measurement context because nausea is subjective and cannot be fully represented by counting emetic episodes. The registry summary says that episode counts correlate poorly with nausea as a subjective symptom. Recording nausea directly, alongside emesis and rescue antiemetic use, therefore distinguishes the reported symptom from observable vomiting and subsequent care.

The endpoint description says that participants completed the visual analogue scale and pictorial scales: the Faces Pain Scale-Revised for pain and BARF for nausea. The visual analogue scale is described as a horizontal line with endpoints for no pain and the worst imaginable pain; higher points indicate more severe or intense pain. The faces scales have scores from 0 to 10, with steps of 2 between faces; higher scores indicate more pain on the pain scale and more nausea on BARF.

The record notes that people with severe nausea are included among those with any nausea, and those with severe emesis among those with any emesis. It also notes overlap: some participants had both nausea and vomiting, so the nausea and emesis counts do not sum to the number with either symptom. The actual endpoint counts and severity thresholds are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What kind of outcome is registered?

The primary endpoint is a count of participants with specified events: nausea, emesis, severe nausea, severe emesis, and rescue antiemetic receipt. In statistical terms, each participant can be classified as having or not having a particular event during the stated assessment window. A count is the number classified as having the event; interpretation of that count normally depends on the number assessed for that outcome. Although the registry lists an enrollment of 208, it does not report the outcome-specific denominators or the counts observed.

The listed categories are not all mutually exclusive. The registry explicitly states that participants with severe nausea are included in the count with any nausea, and participants with severe emesis are included in the count with any emesis. A participant may also have both nausea and vomiting. Consequently, the category counts should not be added to create a total number with symptoms. The record itself warns that the nausea and emesis counts do not sum to the number with either condition.

How should scale scores be understood?

The visual analogue scale is described as a horizontal line whose endpoints represent no pain and the worst imaginable pain. A participant marks a position, and higher points indicate greater pain intensity. The pictorial faces scales use six faces with scores from 0 to 10 in steps of 2. Higher scores indicate more pain on the Faces Pain Scale-Revised and more nausea on BARF. These are ordered ratings: the numerical score communicates an ordering of reported intensity, but the registry description alone does not establish that every score step represents an equal change in the underlying experience.

The scales measure reported symptoms, whereas emesis is an observable event. A statistical analysis of scale ratings would address a different question from an analysis of the number of participants with nausea or vomiting. The registry record does not report scale-score distributions, agreement between instruments, reliability estimates, or validation results. The named assessment tools and their scoring descriptions should not be mistaken for evidence that their measurement properties were established in this study.

What does a confidence interval mean?

As a general statistical explanation, a confidence interval expresses uncertainty around an estimate under the assumptions of the method used to calculate it. For a participant count or event proportion, an interval can convey how imprecisely the event frequency is estimated. A narrow interval generally indicates greater precision than a wide interval, but it does not remove possible bias from missing observations, selection, or measurement error. The registry record does not report confidence intervals for the primary outcome.

As a general point, event counts can be difficult to interpret without a clear denominator and a defined observation period. A count by itself does not communicate the frequency among those assessed. In this record, the primary timeframe is specified as when participants were awake and responding to commands in the PACU, but the number assessed for each listed event is not reported.

What analyses are described?

The registry record lists zero statistical analyses. It does not report a statistical analysis plan, inferential tests, adjustment for covariates, or estimates of association between scores and symptoms. The record also does not state whether analyses were planned at the participant level or whether repeated assessments were combined or evaluated separately. Those details are not reported in the registry record, so no particular model or inferential procedure should be attributed to the study.

As a general statistical point, over-dispersion matters when count data vary more than a statistical model assumes. A model that fails to account for such extra variation can give uncertainty estimates that are too small. That issue is relevant only if an analysis models event counts in that way; the registry record does not report a count model or any assessment of over-dispersion. The primary endpoint is described as participant counts, not as the number of repeated emetic episodes.

How should planning illustrations be read?

The record’s planning 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; the effect to detect is a stated fraction of the observed effect. Such planning calculations concern hypothetical future designs and are not evidence that the present single-cohort study had two arms. They are not observed power, and they do not show that a study would produce the observed effect again.

The planning note specifies that time-to-event calculations report a total number of events, while other calculations report participants per arm. These are conventions for interpreting planning outputs, not a description of the current study’s enrollment or analysis. The registry record does not report the trial’s own sample-size justification or a statistical plan. No additional trial-design rationale should be inferred from the planning assumptions.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome with several related event categories and two secondary outcomes. The primary categories include overlapping groups: severe symptoms are included within the corresponding any-symptom categories, and nausea and emesis can occur in the same participant. These are not independent categories that can simply be combined into a single total.

The registry record does not report a multiplicity strategy, such as adjustment for testing multiple outcomes or a hierarchy specifying which comparisons take priority. It also lists zero statistical analyses. Without reported tests or estimates, there is no basis in the registry record for determining whether multiplicity adjustment was applied or how it might affect statistical interpretation.

Missing-data handling is not reported in the registry record. In particular, the number of participants with completed PACU assessments, missing scale ratings, or unavailable outcome data is not stated. One secondary outcome is explicitly restricted to subjects who returned the post-discharge diary. The number who returned it and any comparison between returners and non-returners are not reported. Results among diary returners, if available, would describe that subset unless an analysis addressed the consequences of non-return.

The record does not define the analysis population for each outcome or state whether all enrolled participants were included. Enrollment is not equivalent to the number with observed endpoint data. Imputation, exclusion rules, and sensitivity analyses are not reported in the registry record, so none should be assumed.

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 registry lists the single cohort with 208 at risk in the serious-adverse-event category and zero serious adverse events. It also lists 208 at risk in the other-adverse-event category and zero other adverse events, with zero deaths. These are the safety figures recorded for the cohort.

These counts are not the primary nausea and emesis outcome results. The primary endpoint concerns postoperative symptoms and rescue antiemetic use in the PACU; the safety figures concern adverse-event reporting. The registry record does not give additional detail about event definitions, collection procedures, follow-up for safety, or how the at-risk counts relate to participants contributing data to the symptom outcomes.

A zero recorded count means that the registry reports no events in that category; it does not establish that the true risk is zero. As a general statistical point, an estimate based on no recorded events can still be uncertain, especially when the population and observation period are limited. No uncertainty interval for these safety figures is reported in the registry record. These data should therefore be read as the reported safety counts, not as proof that adverse events are impossible or that the assessment scales have any particular clinical effect.

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

The record establishes that a completed, single-cohort study examined use of the BARF scale and other symptom scales in children. It specifies a PACU outcome based on participant counts for nausea, emesis, severe symptoms, and rescue antiemetic use, and lists two secondary outcomes involving post-discharge diary reports and age-related ability to use BARF. It also records zero serious adverse events, zero other adverse events, and zero deaths in the safety reporting.

Those details describe the study’s registration and recorded safety figures, but they do not reveal the primary symptom results. The counts of participants with nausea or emesis, the number receiving rescue antiemetics, and the number returning diaries are not reported in the registry record. Nor are scale-score summaries, reliability estimates, or age-stratified findings reported. As a result, the registry record cannot establish how frequently symptoms occurred or whether BARF performed well as a measurement tool.

This distinction matters because an outcome definition is not an outcome finding. Describing a scale, its score range, and the intended assessment time does not show that children understood it consistently or that scores corresponded closely to nausea. Likewise, stating that a study was completed does not supply its results. No treatment comparison is described, so the record does not support a claim that a treatment worked or failed.

The appropriate conclusion is narrow: the study was designed around symptom assessment in a pediatric postoperative setting, and the registry records the specified outcome framework and safety counts. Claims about scale reliability, validity, clinical benefit, symptom frequency, or differences between age groups go beyond the results reported in the registry record.

13. Why This Trial Matters Statistically

This study addresses a measurement challenge in clinical research. Nausea is subjective, while emetic episodes can be counted as observable events. The registry summary states that episode counts correlate poorly with nausea as a subjective symptom. If a study relies only on vomiting counts, it may not capture the experience it intends to measure. Direct symptom ratings and observable event counts therefore answer related but distinct questions.

Using pictorial scales in children is relevant because the registry summary says that the adult visual analogue scale has not been shown to be reliable in young children. BARF is described as a pictorial nausea scale, and the registry includes age-related ability to use it as a secondary outcome. That makes usability across age groups an important measurement question. However, the registry record does not report the findings needed to assess that question.

The study also illustrates why outcome definitions need careful reading. Severe symptoms sit within broader symptom categories, and nausea and emesis can overlap in the same participant. Treating those counts as separate, non-overlapping groups would misrepresent the endpoint. The registry description explicitly warns against summing the symptom categories to obtain a number with either symptom.

Statistically, the record highlights the difference between a measurement plan and evidence about measurement performance. A named scale and a score range explain how a measurement is intended to work; reliability, validity, and age-related usability require results. Because the registry does not report those analyses or the primary counts, the study’s statistical importance lies in the questions it frames, not in a demonstrated finding available in the registry record.

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 most important limitation for interpretation is that the registry record does not report the primary outcome results. It gives the outcome definition and timeframe but not the observed participant counts. No estimates or uncertainty intervals are reported, so the frequency and precision of the symptom outcomes cannot be assessed from the registry record.

The age range and detailed eligibility criteria are not reported. This is particularly relevant because the study concerns children and lists age-related ability to use BARF as a secondary outcome. Without the age distribution or reported age-specific results, usability across developmental stages cannot be evaluated. The record also does not state the threshold used to classify severe nausea or severe emesis.

The secondary post-discharge outcome applies to subjects who returned a diary, but the number of diary returners and the handling of missing diaries are not reported. The numbers assessed for the PACU outcomes are also not reported. Thus, the listed enrollment cannot be treated as the denominator for every outcome.

The study is described as a single cohort, without a separate control group or randomized treatment comparison. It therefore does not provide a registered between-group treatment contrast. The registry also lists zero statistical analyses and does not report methods for handling missing data, repeated scale assessments, or multiple outcomes. Finally, the safety figures do not include further detail about definitions or observation procedures. These limitations restrict interpretation to the registered design and counts, rather than allowing conclusions about instrument performance or clinical effects.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Clinical Use of Baxter Animated Retching Faces (BARF) Scale in Children — NCT02421952.
• 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

The registry record describes a completed, single-cohort study titled “Clinical Use of Baxter Animated Retching Faces (BARF) Scale in Children,” sponsored by Baylor College of Medicine. It lists an enrollment of 208, a start date of 2013-04, primary completion on 2018-03-08, and status COMPLETED.

Participants were asked to assess pain and nausea using visual analogue and pictorial scales in preoperative and postoperative areas. The primary PACU outcome counts participants with nausea, emesis, severe symptoms, and rescue antiemetic use when awake and responding to commands. Listed secondary outcomes concern post-discharge symptoms among diary returners and age-related ability to use BARF.

The registry reports zero serious adverse events, zero other adverse events, and zero deaths. It does not report the primary symptom counts, scale-performance findings, statistical analyses, missing-data methods, or the number contributing to each outcome. The registry record therefore documents the intended assessment framework and safety counts, but not the main results needed to evaluate symptom frequency or BARF performance.