Intravenous Lidocaine Versus Morphine for Severe Pain in the ED: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Intravenous Lidocaine Versus Morphine for Severe Pain in the ED (NCT02912195), a randomized phase 4 study. The primary outcome is Pain Score (NRS 0-10).

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group pilot study comparing intravenous lidocaine with intravenous morphine for severe pain in the emergency department. The registry lists the study as Phase 4, with no masking. It records enrollment of 32 participants and identifies Alameda Health System as the sponsor. The study began in 2016-03, reached primary completion in 2016-09, and is listed as completed.

Random allocation means that the study used chance to assign participants to a treatment group. In a parallel design, each participant is assigned to one group rather than receiving both study treatments in sequence. These design features can support a fair comparison, but they do not by themselves ensure that the groups were similar in every respect, especially in a pilot with limited enrollment. The allocation method and any procedures used to conceal assignments are not reported in the registry record.

The study was open-label: participants and clinical staff were not masked to treatment assignment. This matters because expectations and clinical decisions can affect subjective pain ratings and whether rescue medication is requested or offered. The registry describes provider-chosen morphine dosing and allows participants to elect rescue morphine at 20 and 40 minutes. The full details of rescue procedures in the lidocaine group are not reported in the registry record.

The registry calls the study a pilot, but its sample-size justification, recruitment targets, and any prespecified decision criteria for a later study are not reported in the registry record. The posted enrollment should therefore be read as the size of this study, not as evidence that the study was designed to estimate treatment differences with a particular degree of precision.

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 Pain Score (NRS 0-10), measured over At 60 minutes.

The primary endpoint was pain score at 60 minutes, measured on the Numeric Rating Scale. The scale ranges from 0, meaning no pain, to 10, meaning the worst possible pain. The registry identifies the endpoint as a continuous measure and reports the mean for each treatment group with a 95% confidence interval.

Pain intensity is a direct, patient-reported measure of the symptom the study sought to address. A fixed assessment time gives the groups a common point of comparison, while a numerical scale allows the recorded responses to be summarized and compared statistically. A mean describes the central level of scores in a group; it does not show how every participant felt or how much individual responses varied. The confidence interval conveys uncertainty around the estimated group mean, rather than the range of individual scores.

The primary outcome is a score at one time point, not a measure of the full course of pain over time. Other listed outcomes include pain scores at additional assessments and pain relief compared with baseline at specified times. Those outcomes can add context, but they do not replace the designated primary endpoint. The registry does not report the primary endpoint’s missing-data handling, analysis population, or a comparative statistical analysis.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary endpoint as a continuous outcome and reports a mean with a 95% confidence interval for each arm. A mean is the arithmetic average of participants’ recorded scores. It is useful for describing the average level of a continuous measure, but it can conceal variation across participants and does not describe the shape of the score distribution. The posted primary results do not include a measure of spread such as a standard deviation.

What does a confidence interval convey?

A confidence interval expresses the uncertainty associated with an estimate under the assumptions of the statistical method used. In repeated applications of a method, intervals constructed in this way would contain the true parameter at the stated confidence level at the intended rate, if the assumptions hold. The interval is not a statement that a particular fraction of participants had scores inside its limits. For the reported arm means, the intervals describe uncertainty about each mean; they are not intervals for a difference between arms.

A direct treatment comparison for a continuous endpoint would ordinarily be reported as a contrast, such as a difference in means, with its own uncertainty interval and possibly a test result. Those comparative values are not reported for the primary endpoint. The registry’s analysis information indicates that values needed for a two-arm continuous comparison are missing or not estimable. Consequently, the displayed arm summaries cannot be substituted for a reported comparative analysis. In particular, subtracting one mean from another would create a new calculation rather than recover a sponsor-reported result.

Why does the trial design matter?

Randomization aims to make treatment groups comparable on average with respect to factors present before assignment. It does not guarantee balance in a small study, and it cannot prevent differences that arise after assignment, such as additional treatment or differences in assessment. In an open-label study, knowledge of the assigned treatment may influence participant reports, provider behavior, or other care. This is especially relevant to subjective outcomes such as pain scores and patient choices about rescue medication.

The parallel design means that each participant belongs to one assigned treatment group. It avoids the need to compare a participant’s response under both treatments, but the comparison depends on the groups’ outcomes and on the analysis accounting appropriately for the study design. Details of the randomization procedure, allocation concealment, and the prespecified primary analysis are not reported in the registry record.

How should the secondary analyses be understood?

The registry posts unadjusted recalculations for two secondary outcomes: participants requiring rescue medication and patient satisfaction. An unadjusted analysis describes a comparison without adjustment for other variables. These calculations are not listed as sponsor-reported analyses. Their estimates and confidence intervals can help show the uncertainty in the observed summaries, but they should not be treated as prespecified, definitive tests. The registry does not report the statistical methods used for any sponsor analysis of the secondary outcomes.

For a binary outcome, such as whether a participant required rescue medication, a risk difference expresses the difference between the proportions in the two groups. A confidence interval for that difference reflects uncertainty, and an interval spanning zero is compatible with both directions of difference under the calculation used. The posted recalculations also include unadjusted p-values. A p-value measures how incompatible the observed data are with a specified null model under the test’s assumptions; it does not give the probability that the null hypothesis is true, and it is not a measure of clinical importance.

What do the planning illustrations mean?

The registry includes planning illustrations based on observed effects. These are hypothetical sample-size calculations, not the number of participants actually studied and not observed power. They assume a two-sided significance level of 0.05, equal allocation, and a normal approximation; the assumed effect is a stated fraction of the observed effect. Such illustrations are sensitive to the observed estimate, which can be unstable in a small pilot. They are not a substitute for a prospective sample-size justification, and the trial’s own sample-size justification is not reported in the registry record.

Power is a design property: it is the probability that a planned analysis will detect an effect of a specified size under stated assumptions. Observed power calculated after a study is not a useful replacement for an uncertainty interval. The planning illustrations instead show the approximate group size that would be required under their assumptions to detect the chosen effect with a target power. They should be interpreted as planning aids, not as evidence that this study had a particular chance of finding an effect.

What remains unknown about the analysis?

The registry does not report whether the primary analysis followed an intention-to-treat approach, how missing outcome measurements were handled, whether any participants were excluded after randomization, or whether the statistical plan included interim analyses. These omissions limit the ability to assess the analysis fully. No assumption about those procedures can be made from the posted arm summaries alone.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome and multiple secondary outcomes, including pain scores at different assessments, pain relief at specified times, rescue medication use, and patient satisfaction. Testing or estimating several outcomes creates a multiplicity issue: when many comparisons are considered, the chance of at least one apparently unusual result can increase. This is a general statistical concern, not evidence that any particular posted result is false.

A prespecified analysis plan may identify which outcome is primary, define the intended comparisons, and state whether and how multiplicity will be addressed. The registry record does not report a multiplicity adjustment or a statistical plan for the secondary outcomes. The posted unadjusted secondary calculations should therefore be considered exploratory, and their p-values should not be read as if they account for all outcomes assessed.

Missing-data procedures also affect interpretation. The registry reports the number analyzed for the primary endpoint by arm, but the method for handling missing measurements and the reason for any unavailable outcomes are not reported in the registry record. For patient satisfaction, the listed group sizes differ from those for the primary outcome; the reason for that difference is not reported in the registry record. The registry does not state whether missing outcomes were imputed, whether participants with missing values were excluded, or whether sensitivity analyses were performed.

The analysis population is not described. In particular, the registry does not say whether the reported summaries include all randomized participants according to their assigned groups, or whether a different population was used. The statistical analysis plan, interim analyses, and any rules for stopping the study early are not reported in the registry record. Without those details, the posted summaries can be described, but the analysis cannot be fully evaluated against a prespecified plan.

11. Safety Results

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

Other (non-serious) adverse events

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

Most frequent non-serious adverse event terms

The registry reports serious adverse event counts for participants at risk in each treatment group. The recorded number affected by serious adverse events is 0 of 16 in the intravenous lidocaine group and 0 of 16 in the morphine group. These are counts within this study, not proof that serious events cannot occur with either treatment. A small study may not capture uncommon harms, and the registry does not report event terms for serious adverse events.

For other adverse events, the registry records 2 of 16 participants affected in the lidocaine group and 6 of 16 in the morphine group. The event types, severity details, timing, and assessment procedures are not reported in the registry record. The counts should not be treated as a causal comparison or as a complete safety profile, especially given the open-label design and limited enrollment.

Death counts are not reported in the registry record. The adverse event information is therefore limited to the recorded group counts and should be read as descriptive safety reporting from this pilot, rather than as a definitive estimate of comparative risk.

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

The study provides randomized, open-label pilot data on intravenous lidocaine and provider-chosen intravenous morphine for severe pain in the emergency department. Its primary outcome is a patient-reported pain score at 60 minutes. The posted arm-level means and confidence intervals describe the observed group summaries and their uncertainty, but the registry does not report a primary comparative estimate or test. That absence prevents a direct statistical reading of the primary treatment contrast from the registry record.

The findings do not establish that the treatments are equivalent. A lack of a reported comparison is not evidence that the groups are the same, and overlapping confidence intervals for separate arm means do not serve as a formal test of the difference. The results also do not establish that either treatment is superior. Those conclusions would require a reported comparative analysis with its estimate and uncertainty, interpreted in light of the study design and analysis plan.

The secondary outcomes add descriptive context, but only selected outcomes have posted unadjusted comparative recalculations. Multiple outcomes, incomplete analysis reporting, and the uncertainty associated with a pilot study make those results less suitable for confirmatory claims. The safety counts likewise describe events recorded in the study and cannot determine uncommon risks or provide a complete assessment of comparative safety.

The record does not report a sample-size justification, a complete analysis plan, missing-data methods, or the analysis population. Those limitations affect how confidently the reported summaries can be connected to the original study objectives. The posted results are best understood as preliminary information that may help frame a more fully specified study, not as a final answer to the clinical comparison.

13. Why This Trial Matters Statistically

This trial is statistically instructive because it combines random allocation with a pilot-scale enrollment and an open-label design. Randomization is valuable for reducing systematic differences at assignment, but a randomized study still needs a clearly reported analysis to quantify the treatment contrast. Here, the primary outcome is summarized separately by arm, while a direct comparative estimate is not reported in the registry record. That distinction is central: descriptive summaries are not the same as an estimate of the difference between groups.

The case also illustrates why precision matters. A confidence interval around each mean communicates uncertainty about that group’s average, but it does not answer the comparative question by itself. A useful report of a primary comparison would ordinarily make the contrast and its uncertainty explicit. Without those values, readers cannot judge the range of between-group effects compatible with the primary results based on the registry record.

Open-label assessment is another relevant statistical consideration when outcomes depend on participant reports or choices. Knowledge of treatment assignment could influence ratings or rescue medication use. This does not show that such influence occurred, but it is a potential source of bias to consider when interpreting subjective outcomes.

Finally, the record shows why exploratory secondary analyses and planning calculations need careful labels. Unadjusted findings across multiple outcomes are not equivalent to confirmatory evidence, and sample-size illustrations based on observed effects are not the study’s design justification or observed power. Clear separation of descriptive results, comparative inference, and planning assumptions helps prevent stronger conclusions than the reported evidence supports.

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.

Several limitations are specific to the available record for this study. The primary outcome is reported as a mean and confidence interval for each arm, but the registry does not provide the primary between-group estimate, its confidence interval, or a p-value. The analysis information indicates that values needed for a two-arm continuous comparison are missing or not estimable. This leaves the main comparative question without a reported primary analysis.

The enrollment was 32, consistent with the registry’s description of the study as a pilot. The record does not report the rationale for that enrollment or a prospective sample-size justification. The sample-size illustrations are based on observed effects and assumptions, so they cannot establish what the original study was designed to detect.

The open-label design may be important because the primary endpoint is a subjective pain rating and some secondary outcomes depend on participant choices or reports. The registry also describes morphine dosing as provider-chosen, while the lidocaine regimen is described with weight-based dose categories. The full lidocaine description is incomplete in the record, and the full protocol details are not reported in the registry record.

Additional limitations include unreported analysis-population definitions, missing-data procedures, and multiplicity methods. The registry lists multiple outcome measures, but does not provide comparative analyses for all listed outcomes or a plan for interpreting them together. The types of other adverse events are not reported, and death counts are not reported in the registry record. These gaps restrict assessment of both efficacy analyses and safety reporting.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Intravenous Lidocaine Versus Morphine for Severe Pain in the ED — NCT02912195.
• Registry record last updated 2020-04-06; status last verified 2020-03.
• Results first posted 2020-04-06.
• 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 identifies NCT02912195 as a completed Phase 4, randomized, open-label, parallel pilot study sponsored by Alameda Health System. It compares intravenous lidocaine with provider-chosen intravenous morphine for severe emergency-department pain. Enrollment was 32; the study began in 2016-03 and reached primary completion in 2016-09.

The primary endpoint was mean pain score on the 0–10 Numeric Rating Scale at 60 minutes. The record reports arm-level means and 95% confidence intervals but does not report a primary between-group analysis. Secondary outcomes include additional pain and pain-relief assessments, rescue medication use, and patient satisfaction. Selected secondary outcomes have unadjusted recalculations; sponsor-reported analyses are not listed.

The record does not report the sample-size justification, analysis population, missing-data methods, or multiplicity plan. Safety reporting includes serious and other adverse event counts, but event details are limited.