This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Randomized Clinical Trial of Propofol, 1:1 and 4:1 Combination of Propofol and Ketamine for Procedural Sedation (NCT01260662), a randomized phase 4 study. The primary outcome is Clinical Interventions During Sedation.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01260662 |
| Phase | Phase 4 |
| Condition | Procedural Sedation |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 271 |
| Arms in the primary outcome | 3 |
| Lead sponsor | Hennepin Healthcare Research Institute |
| Results posted | Yes |
2. Clinical Question
Population
Patients seen in the emergency department who required procedural sedation for a painful procedure. The primary outcome description identifies 100 subjects randomized to each group.
Intervention
Propofol/ketamine combinations: a 1:1 mixture or a 4:1 mixture. Both descriptions specify an initial bolus of 0.1 cc/kg followed by half that dose every 3 minutes as needed for sedation.
Comparator
Propofol, described as deep sedation using propofol.
Primary question
How many clinical interventions were performed during sedation in each group? Listed interventions include supplemental oxygen, stimulation to induce respiration, airway repositioning, assisted ventilation, and endotracheal intubation.
The registry describes a randomized comparison among three sedation regimens for emergency department procedures. The clinical rationale recorded for studying combinations is that the agents have different potential unwanted effects. That rationale motivates the comparison; it is not evidence that combining the agents avoids those effects.
The primary outcome is a count of clinical interventions, not a posted measure of pain, satisfaction, or procedural recall. The registry describes pain, memory, and satisfaction assessments in its study summary, and lists respiratory depression and procedural recall as secondary outcomes. It does not post their results in the registry record reported for this analysis. The primary results therefore address intervention counts during sedation, rather than the full set of experiences or safety outcomes described in the study rationale.
3. Trial Design
The registry identifies this as a Phase 4, randomized, parallel-group trial with quadruple masking. Its official title describes a blinded, three-arm study in the emergency department. The three arms were propofol, a 1:1 propofol/ketamine combination, and a 4:1 propofol/ketamine combination. The sponsor is Hennepin Healthcare Research Institute, and the registry status is completed.
The listed study start is 2010-11, and primary completion is 2013-08. Registry enrollment is 271. Separately, the primary outcome description states that 100 subjects were randomized to each group and gives the numbers who completed the study in each arm: 90 for propofol, 85 for the 1:1 combination, and 96 for the 4:1 combination. These figures are reported as written; the registry record does not explain their relationship to the enrollment entry.
The propofol arm is described as deep sedation using propofol. For each combination arm, the description specifies a mixture ratio, an initial bolus of 0.1 cc/kg, and a follow-up dose of half that amount every 3 minutes as needed for sedation. The registry summary says patients were monitored during the procedure using cardiac monitoring, non-invasive blood pressure monitoring, pulse oximetry, nasal sample end-tidal carbon dioxide, and physician assessment.
Quadruple masking is recorded, but the roles included in that masking designation are not reported in the registry record. Details about the randomization sequence, concealment, and implementation are also not reported in the registry record. The posted information identifies the overall design but does not provide enough detail to assess how these procedures were carried out.
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.
Before assignment: 271 enrolled subjects underwent procedural sedation
Overall Study
| Stage | Propofol | 1:1 Propofol/Ketamine | 4:1 Propofol/Ketamine |
|---|---|---|---|
| STARTED | 90 | 85 | 96 |
| COMPLETED | 90 | 85 | 96 |
| NOT COMPLETED | 0 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: 100 subjects were randomized to each group, 90 subjects in the propofol arm completed the study, 85 in the 1:1 propofol/ketamine arm, and 96 in the 4:1 propofol/ketamine arm
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: Baseline Participants include any individual who received drug and underwent procedural sedation.
| Characteristic | Unit | Propofol | 1:1 Propofol/Ketamine | 4:1 Propofol/Ketamine | Total |
|---|---|---|---|---|---|
| Participants analysed | 90 | 85 | 96 | 271 | |
| Age, Continuous | years | 40 (18 to 83) | 39 (18 to 80) | 36 (18 to 84) | 38 (18 to 84) |
| Sex: Female, Male: Female | Participants | 43 | 40 | 45 | 128 |
| Sex: Female, Male: Male | Participants | 47 | 45 | 51 | 143 |
| Region of Enrollment: United States | participants | 90 | 85 | 96 | 271 |
6. Primary Endpoint
The registry lists the primary outcome as Clinical Interventions During Sedation, measured over From start of sedation procedure to end of sedation procedure, up to 24 hours.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Clinical interventions performed |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled Clinical Interventions During Sedation, with the unit stated as clinical interventions performed. Its timeframe runs from the start to the end of the sedation procedure, up to 24 hours. The listed events are adding or increasing supplemental oxygen, stimulating the patient to induce respiration, repositioning the airway, providing assisted ventilation, and performing endotracheal intubation.
These actions are relevant to procedural sedation because they describe responses to clinical needs during the sedation period. Counting such interventions offers a way to describe the amount of clinical intervention recorded while the procedure is underway. The registry does not provide a definition of how the count was constructed when more than one listed action occurred, or whether repeat instances of the same action were counted separately. Those details are not reported in the registry record.
The posted arm values are 41 for propofol, 33 for the 1:1 combination, and 48 for the 4:1 combination. They should be read as the reported endpoint values, not as percentages or as the number of participants who experienced an event: the endpoint unit is clinical interventions performed. No measure of spread or uncertainty accompanies these values. Without further endpoint definitions and analysis details, they describe the recorded counts but do not establish the size or precision of a treatment-group difference.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry reports clinical intervention counts of 41 in the propofol group, 33 in the 1:1 propofol/ketamine group, and 48 in the 4:1 propofol/ketamine group. These are descriptive results for the primary endpoint. The record does not provide a statistical comparison among the arms, an effect estimate, a confidence interval, or a p-value. It therefore does not establish whether the differences in the posted counts are compatible with chance variation or indicate a reliable difference between regimens.
The groups also have different reported numbers of participants who completed the study: 90, 85, and 96, respectively. The intervention values are counts, and the registry does not report a rate, a participant-level risk, or a standardized comparison accounting for group size. The values should not be interpreted as the proportion of patients who needed an intervention. Nor should the arm counts be converted into rates without the required endpoint definition and analysis information.
Counts can be informative, but their interpretation depends on how the events were counted and on their distribution across participants. For example, a count may reflect repeated interventions in one person or single interventions across several people; the posted summary does not distinguish these patterns. The registry also does not report a mean, variance, median, range, or other distributional description for this outcome.
The numerical ordering of the three observed counts is not by itself evidence of a treatment effect. Randomization supports a planned comparison, but the registry record does not post the results of an inferential analysis. The sample-size assumptions describe a planning illustration based on an observed effect; such an illustration is not an observed-power result and does not substitute for a treatment-effect estimate or uncertainty interval.
The registry lists respiratory depression and procedural recall as secondary outcomes, but their results are not included in the posted outcome details for this analysis. The brief summary also describes pain, memory, and satisfaction assessments, without outcome results for them in the record described. Thus, the primary count endpoint is the only efficacy-related result that can be interpreted from these posted values. The appropriate conclusion is limited: the record gives arm-specific intervention counts, while the comparative magnitude, precision, and statistical evidence are not reported in the registry record.
9. Statistical Methods Explained
The design is recorded as randomized, parallel, and quadruple-masked. In general, random assignment is intended to make treatment groups comparable with respect to factors that could influence outcomes, while masking is intended to limit the influence of treatment knowledge on care or assessment. Those are general purposes of these design features, not findings about how successfully they were implemented in this trial. The sequence-generation process, allocation concealment, and masking roles are not reported in the registry record.
What kind of outcome was recorded?
The primary endpoint is a count of clinical interventions performed during sedation. Count outcomes differ from continuous measures such as a score and binary outcomes such as whether an event occurred. A count retains information about the number of recorded actions. Here, the listed actions include oxygen supplementation, stimulation to induce respiration, airway repositioning, assisted ventilation, and intubation. The registry does not describe whether the count combines all actions in a participant, how repeated actions are treated, or whether the reported arm values are totals under a more specific convention.
As a general statistical consideration, count data may be unevenly distributed: many participants can have few or no events while a smaller number have several. Over-dispersion occurs when the variability in counts is greater than a simple count model would expect. If present, it can make standard errors from an overly restrictive model too small and confidence intervals too narrow. This is a general explanation, not a claim that over-dispersion occurred in this trial. The record does not report a distributional assessment, a model, or a measure of dispersion for the primary endpoint.
What do the posted numbers estimate?
The reported values are 41, 33, and 48 clinical interventions for the propofol, 1:1 combination, and 4:1 combination arms, respectively. The registry gives no accompanying spread, confidence interval, or inferential result. A confidence interval, in general, expresses uncertainty around an estimated quantity under the assumptions of the analysis. Without an estimate and interval, readers cannot assess the precision of these arm results or the range of comparative effects compatible with the analysis.
The record identifies the endpoint unit as interventions performed, not interventions per participant or the proportion of participants with any intervention. The primary description also reports numbers completing the study by arm, but it does not state how those analysis populations were used to produce the endpoint values. A comparison of raw counts can be affected by the number of people observed and the distribution of events. The registry entries do not provide enough information to make an adjusted or standardized comparison.
What analysis is documented?
The record lists zero analyses. It does not report a statistical model, a method for comparing the three arms, a test statistic, an effect estimate, a p-value, or a confidence interval. There is consequently no sponsor-reported comparative analysis to summarize. The registry entries do not identify a protocol-defined statistical plan, and the analysis approach is not reported in the registry record. No independent recalculation is presented in the registry entries.
The registry describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes planning for a stated fraction of the observed effect. In general, such calculations illustrate a sample size for a specified design and assumed effect. They do not establish the trial's original sample-size justification, and they are not observed power. The actual planning values are not included in the registry record used for this interpretation, and the registry does not report that these assumptions were the trial's own design assumptions.
For a three-arm trial, a full statistical account would make clear which pairwise or overall comparisons were planned, how the count outcome was modeled, which participants were included, and how uncertainty was calculated. The registry record does not provide those details. The posted numbers can therefore be described, but they cannot be treated as results of a documented comparative statistical procedure.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists four outcome measures and identifies two secondary outcomes: respiratory depression and procedural recall. The primary endpoint is clinical interventions during sedation. Results for the two listed secondary outcomes are not reported in the registry record. The brief study summary describes assessments of perceived pain, memory, and satisfaction, but the posted outcome details do not include results for those assessments.
When a study evaluates multiple outcomes or multiple treatment contrasts, the chance of at least one apparently notable result can increase. General approaches to multiplicity include prespecifying a primary comparison or adjusting inference across a family of tests. The registry record does not report a multiplicity strategy, identify a hierarchy of comparisons, or provide a set of outcome-specific analyses. No correction or adjusted p-value is reported. Because no comparative analyses are posted, the impact of multiplicity on any treatment conclusion cannot be assessed.
The primary endpoint description states that 100 subjects were randomized to each group, while the arm-specific completion counts are 90, 85, and 96. The registry enrollment entry is 271. The record does not explain the relationship among these entries, identify reasons for non-completion, or describe missing outcome data. It does not report whether the analysis included all randomized participants, only participants who completed the study, or another analysis population.
In general, missing outcome data can affect interpretation when the probability of missingness is related to treatment assignment or outcome. Assessing that possibility requires information about missingness and the analysis approach. Those details, including any imputation or sensitivity analysis, are not reported in the registry record. The reported completion counts alone do not establish why participants did not complete the study or whether endpoint data were available for everyone in each stated group.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Propofol | 0 | 90 | 0.0% |
| 1:1 Propofol/Ketamine | 0 | 85 | 0.0% |
| 4:1 Propofol/Ketamine | 0 | 96 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 3% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Propofol | 0 of 90 |
| 1:1 Propofol/Ketamine | 0 of 85 |
| 4:1 Propofol/Ketamine | 0 of 96 |
The registry reports zero serious adverse events and zero other adverse events in each listed arm. The numbers at risk for these summaries are 90 for propofol, 85 for the 1:1 propofol/ketamine combination, and 96 for the 4:1 combination. These figures are safety summaries as recorded; they are separate from the primary count of clinical interventions during sedation.
Zero reported events in a registry summary should be read as a description of what was reported for the listed groups, not as proof that an event is impossible or that the regimens have identical safety. The record does not provide comparative safety estimates, confidence intervals, or statistical tests. It also does not list serious adverse event terms. Death counts are not reported in the registry record.
The clinical intervention endpoint includes actions such as adding oxygen or assisting ventilation. These are not equivalent to the registry's adverse-event categories. A clinical intervention count and an adverse-event report answer different questions and should not be substituted for one another. The registry record does not provide enough detail to reconcile those endpoint categories or to assess how events were classified and collected.
12. What the Result Does, and Does Not, Mean
The posted results establish that the registry reports different raw counts of clinical interventions across the three treatment arms: 41 with propofol, 33 with the 1:1 propofol/ketamine combination, and 48 with the 4:1 combination. They also establish that the record lists zero serious and zero other adverse events in each arm. These are descriptions of the results as registered, not estimates of causal effects or proof that the regimens differ or are equivalent.
The results do not establish that one regimen reduces the need for clinical interventions. The registry does not report a treatment contrast, uncertainty interval, p-value, or analysis model for the primary endpoint. The arm values are counts rather than rates or percentages, and the record does not clarify how repeated interventions were counted. No conclusion about relative effectiveness can be drawn from the ordering of the raw counts alone.
Likewise, the adverse-event entries do not establish that there were no possible safety concerns. They describe zero reported events in the listed categories and groups, without a comparative analysis or detail about ascertainment. Deaths are not reported in the registry record. Results for respiratory depression and procedural recall, which are listed as secondary outcomes, are also not reported in the registry record for interpretation.
The study summary gives a rationale for comparing propofol with propofol/ketamine combinations and describes patient monitoring and post-procedure assessments. A rationale is not a result. The posted primary values do not answer questions about pain, memory, satisfaction, or all aspects of sedation experience. They are limited to the recorded clinical intervention count and the reported adverse-event summaries.
In statistical terms, the central limitation is not simply that the values are counts; it is that the record does not provide enough analysis detail to quantify comparative effects or their precision. A complete interpretation would require a defined count-analysis method, an analysis population, and uncertainty estimates, as well as results for the other outcomes. Without those details, the registry supports descriptive reading only.
13. Why This Trial Matters Statistically
This trial is statistically notable as a randomized comparison of three sedation regimens with a count endpoint. The design raises practical analytical questions that arise in many clinical studies: how to compare more than two groups, how to interpret a count outcome, and how to connect the analyzed population to the number randomized and the number who completed the study.
Its primary endpoint combines several clinically distinct actions, from supplemental oxygen to assisted ventilation and intubation. Counting actions can provide a concise summary, but the meaning of that summary depends on event definitions and counting rules. The registry record does not say whether repeated actions are counted separately or how the distribution of events across participants was handled. That missing context limits what the raw arm counts can convey.
The study also illustrates why randomization and masking do not replace reporting of statistical methods. A randomized design provides a basis for comparison, but readers still need the analysis population, the planned contrasts, a model suited to the endpoint, and measures of uncertainty to judge the results. Those comparative analyses are not reported in the registry record.
Finally, the registry includes different entries for enrollment and for the number described as randomized in the primary outcome population, alongside arm-specific completion counts. Reporting how those figures relate would help readers understand the path from trial enrollment to endpoint analysis. In this record, that relationship and the handling of missing data are not explained. The example underscores the value of transparent endpoint definitions and analysis reporting when a clinical trial presents count outcomes across multiple arms.
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 primary endpoint is described as a number of clinical interventions, but the registry does not specify the counting rules in enough detail to determine whether repeated actions were counted separately or how events were combined within participants. The listed actions also differ in kind. The posted count does not show which actions contributed to each arm's value or how counts were distributed among participants.
The registry lists enrollment as 271, while the primary outcome description says 100 subjects were randomized to each group. It also reports arm-specific completion counts of 90, 85, and 96. The relationship between these entries is not explained in the registry record. Reasons for not completing the study, endpoint availability, and the analysis population are not reported, which limits interpretation of the denominators underlying the primary values.
No comparative analysis is posted for the primary endpoint. There is no reported model, effect estimate, confidence interval, or p-value, and no explanation of how the three arms were compared. The record does not report the statistical analysis plan, randomization procedures in detail, masking roles, or multiplicity handling. These absences prevent assessment of the precision and robustness of the observed arm counts.
Several outcomes described in the study summary or listed as secondary outcomes lack results in the record details used. The adverse-event entries report zero events in the listed categories, but provide no event terms, comparative uncertainty, or death counts. The record does not explain outcome ascertainment or how the primary clinical-intervention endpoint relates to adverse-event reporting.
The registry record also does not explain the difference between its enrollment entry and the randomized-group statement in the primary outcome description. These limitations do not change the posted counts; they constrain how far those counts can support interpretation.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Randomized Clinical Trial of Propofol, 1:1 and 4:1 Combination of Propofol and Ketamine for Procedural Sedation — NCT01260662.
- Registry record last updated 2015-07-14; status last verified 2015-06.
- Results first posted 2015-04-29.
- 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.
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18. Record Summary
NCT01260662 is a completed Phase 4 randomized, parallel-group trial with quadruple masking. It compared propofol with 1:1 and 4:1 propofol/ketamine combinations for procedural sedation in the emergency department. Hennepin Healthcare Research Institute is listed as sponsor. The recorded study start is 2010-11 and primary completion is 2013-08; registry enrollment is 271.
The primary endpoint is the count of clinical interventions during sedation. The posted values are 41 for propofol, 33 for the 1:1 combination, and 48 for the 4:1 combination. The registry reports zero serious and zero other adverse events in each listed arm. It does not report comparative statistical analyses, uncertainty estimates, results for the listed secondary outcomes, or the analysis population and missing-data approach.