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 the Effect of Dopamine on Mechanical Ventilation Induced Lung Injury (NCT03317431), a registered phase not stated study. The primary outcome is Correlation Coefficient (r) Between Duration of Mechanical Ventilation and DRD1 Expression.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03317431 |
| Phase | Phase not stated |
| Condition | Acute Lung Injury |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 46 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Xinhua Hospital, Shanghai Jiao Tong University School of Medicine |
| Results posted | Yes |
2. Clinical Question
Population
The registry describes patients undergoing selective operation with general anesthesia and mechanical ventilation. Acute Lung Injury is listed as a condition. Enrollment is recorded as 46, but the registry record does not report how many participants contributed data to the primary analysis, or whether all enrolled participants had usable measurements.
Intervention
The registered intervention is mechanical ventilation. The study description discusses dopamine and the possible mechanisms linking dopamine receptors with ventilation-induced lung injury, but the registry does not list dopamine administration as an intervention. The record therefore does not establish a comparison of dopamine treatment against a control treatment.
Comparator
No like-for-like control comparison is reported. The registry notes that the study was not a randomized comparison, that allocation was not stated, and that the arms are not a like-for-like control comparison. The available record does not specify a separate comparator group suitable for estimating a treatment contrast.
Primary question
The primary outcome asks whether the duration of mechanical ventilation is associated with lung-tissue DRD1 expression over the stated timeframe of 20min-60min. DRD1 expression was based on a normalized chemiluminescent signal. The intended statistic is Pearson’s correlation coefficient, which describes the direction and strength of a linear association. The numeric coefficient, its uncertainty, and its p-value are not reported in the registry record, so the direction, magnitude, and statistical precision of the association cannot be assessed from this record.
3. Trial Design
The registry identifies this as a completed study sponsored by Xinhua Hospital, Shanghai Jiao Tong University School of Medicine. Its recorded enrollment is 46. The study start date is 2017-03-20, and the primary completion date is 2017-10-22. The registered intervention is mechanical ventilation, and the described group comprises patients undergoing selective operation with general anesthesia and mechanical ventilation.
The title and study description focus on dopamine and mechanical ventilation-induced lung injury, including possible mechanisms involving dopamine receptors. However, the intervention recorded in the registry is mechanical ventilation, not dopamine administration. The record therefore describes an investigation of ventilation duration and tissue-expression measures, rather than a registered randomized comparison of dopamine against another treatment.
The registry explicitly indicates that this was not a randomized comparison, that allocation was not stated, and that the arms are not a like-for-like control comparison. It does not report a protocol-level account of how participants entered groups or how a comparison group was defined. The enrollment figure does not establish how many participants had primary outcome data or were included in any analysis.
The primary outcome is a correlation between duration of mechanical ventilation and DRD1 expression, with the stated timeframe 20min-60min. Four secondary outcomes concern DRD2 expression in relation to ventilation duration, and expression of TH, DDC, and Ac-a-tubulin in lung tissues. The registry lists five outcome measures and five analyses. It does not provide numerical results for those outcomes in the registry record for this analysis. The record is marked completed, but completion status alone does not indicate whether every planned analysis was conducted or reported.
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
| Stage | Ventilation |
|---|---|
| STARTED | 46 |
| COMPLETED | 46 |
| NOT COMPLETED | 0 |
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.
| Characteristic | Unit | Ventilation |
|---|---|---|
| Participants analysed | 46 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 46 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 13 |
| Sex: Female, Male: Male | Participants | 33 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 46 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 |
| Race (NIH/OMB): White | Participants | 0 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: China | participants | 46 |
6. Primary Endpoint
The registry lists the primary outcome as Correlation Coefficient (r) Between Duration of Mechanical Ventilation and DRD1 Expression, measured over 20min-60min.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | pearson Correlation Coefficient |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the Pearson correlation coefficient between duration of mechanical ventilation and DRD1 expression. It is intended to characterize whether measured ventilation duration and measured receptor expression vary together in a linear pattern. A positive association would indicate that larger values of one measure tend to accompany larger values of the other; a negative association would indicate that larger values of one tend to accompany smaller values of the other. The coefficient describes association, not a causal effect.
DRD1 expression was assessed using ImageJ to obtain the integrated optical density of a chemiluminescent signal from membranes. The registry description says the DRD1 signal was normalized by total β-actin signal to correct for sample loading. A bulk preparation of normal placental protein was used as a control when comparing expression at different time points. These details explain how the molecular measurement was constructed; they do not report the observed correlation.
The stated timeframe is 20min-60min. The registry describes a significance criterion of p value less than 0.05 for a change. However, the numeric correlation, p-value, confidence interval, and analyzed sample size are not reported in the registry record. Without those results, the endpoint’s observed direction, magnitude, and precision cannot be described.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary outcome is defined as Pearson’s correlation between mechanical ventilation duration and DRD1 expression, but the numeric coefficient is not reported in the registry record. The record also does not report a confidence interval or p-value for that endpoint. Consequently, the observed direction and magnitude of the association, and the precision with which it was estimated, are unknown from this record. A significance threshold is described, but a threshold is not itself an outcome and cannot establish whether the observed result met it.
The study description gives a biological rationale involving dopamine and ventilation-induced lung injury. That rationale is distinct from the numerical evidence needed to evaluate the primary association. A correlation can describe whether two measured quantities vary together, but it cannot by itself show that one quantity caused a change in the other. The nonrandomized design and the absence of a like-for-like control comparison further mean that the record does not support interpreting the primary endpoint as a randomized treatment effect.
The registry lists four secondary outcomes: the correlation between ventilation duration and DRD2 expression, and lung-tissue expression of TH, DDC, and Ac-a-tubulin. Numerical results for these outcomes are not reported in the registry record. Although the record lists five outcome measures and five analyses, that count does not reveal the estimates, their uncertainty, or whether all were analyzed in the same participants.
Enrollment is recorded as 46, but the number with observed primary outcome data and the number analyzed are not reported in the registry record. This distinction matters because enrollment does not establish the analysis denominator. Missing measurements, exclusions, or other reasons for differences between enrollment and analysis cannot be evaluated without participant-flow and analysis-population details.
The record’s adverse-event entries list zero at-risk denominators and zero events for the ventilation group. Those entries do not establish that no adverse events occurred: with no reported at-risk denominator, the event fields are not an interpretable account of safety incidence. They should not be used to infer the absence of harm.
Any sample-size figures associated with this material are planning illustrations based on the observed effect, not observed power or a description of the trial’s original design justification. The registry record does not report the trial’s sample-size justification. Without the underlying effect estimate and analysis details in the record, the planning figures cannot establish the precision of the completed study or resolve the missing outcome results.
9. Statistical Methods Explained
What does a correlation coefficient describe?
In general, a correlation coefficient summarizes the direction and strength of a linear association between two measured quantities. Here, the intended quantities are duration of mechanical ventilation and normalized DRD1 expression. The coefficient would help describe whether higher values of ventilation duration tend to occur alongside higher or lower values of DRD1 expression. It does not describe a treatment contrast, and it does not establish that ventilation duration caused a change in receptor expression.
Pearson correlation is most directly informative when the relationship is reasonably represented by a straight-line pattern and when unusual observations do not dominate the result. It can miss a nonlinear relationship, and a single coefficient can obscure subgroup patterns or influential observations. The registry record does not report plots of individual observations, checks of model assumptions, or sensitivity analyses. These aspects of the analysis are therefore not reported in the registry record.
How was DRD1 expression measured?
The registry description says ImageJ was used to measure integrated optical density from a chemiluminescent membrane signal. DRD1 optical density was divided by total β-actin optical density as a sample-loading correction. In general, normalization aims to make measurements more comparable when the amount of material loaded differs between samples. It does not remove every possible source of measurement variation, and interpretation depends on the quality and consistency of both the target and normalization signals.
The record also says a bulk preparation of normal placental protein was used as a control when determining DRD1 expression at different time points. That describes a measurement reference; it is not described as a clinical comparison group. The record does not report assay validation, repeatability, blinding of laboratory measurement, or how measurement variability was incorporated into the statistical analysis.
What would a confidence interval add?
In general, a confidence interval expresses the uncertainty around an estimated quantity under the assumptions of the analysis. For a correlation, it would help show which association strengths remain compatible with the observed data and model. A narrow interval would indicate greater statistical precision than a wide interval, while neither width nor location alone proves causality. No confidence interval for the primary correlation is reported in the registry record, so its precision cannot be assessed.
How should the p-value be read?
The outcome description states that a p value less than 0.05 would be treated as statistically significant. In general, a p-value measures how incompatible the data are with a specified null model, given the model’s assumptions. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of an association. Since the primary p-value is not reported in the registry record, it is not possible to determine whether the stated criterion was met. Even if it were reported, it would need to be considered alongside the estimate, its uncertainty, study design, and outcome measurement.
What does the design allow the analysis to conclude?
The registry notes that this was not a randomized comparison, allocation was not stated, and the arms are not a like-for-like control comparison. In general, randomized allocation can help balance factors that influence both exposure and outcome, whereas a nonrandomized association may reflect other differences between participants or measurement times. The record does not report an adjusted model or the covariates considered. Therefore, it is not possible to assess whether the primary association was adjusted for other factors.
The outcome description gives a specific measurement process and timeframe, but the registry record does not report the analyzed sample size, missing-data approach, or model diagnostics. These details matter because incomplete measurements and departures from analysis assumptions can affect estimates and their uncertainty. Enrollment alone cannot substitute for the number contributing to a particular analysis.
The record lists five outcomes and five analyses. In general, examining multiple outcomes can raise the chance of obtaining at least one apparently notable result by chance if no adjustment or prespecified hierarchy is used. Whether multiplicity was addressed is not reported in the registry record. No numerical outcome results are available to evaluate alongside that issue.
Planning sample-size calculations are different from evidence about the completed study. The stated planning approach uses a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect expressed as a fraction of the observed effect; non-time-to-event figures are participants per arm. These are planning illustrations, not observed power. The registry record does not report the original sample-size justification, and the nonrandomized arms are not a like-for-like comparison. A planning illustration based on an observed effect should not be read as proof that the design had adequate precision or that the effect is reproducible.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists five outcome measures and five analyses: a primary correlation involving DRD1 and four secondary measures involving DRD2, TH, DDC, and Ac-a-tubulin. It does not report whether one outcome was designated as the sole confirmatory test, whether a hierarchy of tests was prespecified, or whether any adjustment for multiple testing was planned or used. The multiplicity approach is not reported in the registry record. In general, testing several outcomes can make chance findings more likely, so interpretation should consider the full set of analyses rather than a selected result.
The record lists enrollment as 46, but does not state how many participants contributed to each outcome, whether data were missing, or how missing measurements were handled. It does not report analysis populations, exclusions, or reasons for unavailable measurements. Those details are necessary to understand the denominators behind estimates and whether the analyzed participants differ from those enrolled.
The adverse-event record lists zero participants at risk and zero events for the ventilation group. Because the at-risk denominator is zero, those entries cannot be read as evidence that no events occurred or as an estimate of event incidence. A fuller account of safety ascertainment is not reported in the registry record.
11. What the Result Does, and Does Not, Mean
The registry describes an investigation of the relationship between mechanical ventilation duration and lung-tissue expression measures, with a primary focus on DRD1. It also outlines a rationale concerning dopamine and ventilation-induced lung injury. The numeric primary result and the numeric secondary results are not reported in the registry record, so the record does not establish the direction, size, or precision of any observed association.
The primary endpoint is a correlation, not a randomized treatment contrast. The registered intervention is mechanical ventilation, and the record says the comparison was not randomized, allocation was not stated, and arms were not like-for-like. The findings therefore cannot be interpreted from this record as evidence of a causal effect of dopamine or of a treatment benefit. Dopamine administration is not listed as a registered intervention.
The absence of a reported estimate is not evidence that the association was absent, and a significance threshold does not reveal whether a result was statistically significant. Likewise, the enrollment figure does not show how many participants were analyzed. The record does not report the primary estimate, its uncertainty, the p-value, or the analysis denominator needed to assess the strength and precision of the evidence.
The listed adverse-event entries do not establish safety because the at-risk denominator is recorded as zero. A completed status indicates the registry marks the study completed; it does not fill the gaps in outcome reporting or analysis methods. Conclusions should remain limited to the study question and methods described in the record, without treating mechanistic motivation as a clinical outcome.
12. Why This Trial Matters Statistically
This study illustrates why the registered research question, intervention, outcome, and analysis need to be read together. The title and rationale emphasize dopamine, while the listed intervention is mechanical ventilation and the primary endpoint is a correlation between ventilation duration and DRD1 expression. That distinction affects what the design can estimate: a molecular association is not equivalent to a randomized comparison of dopamine treatment.
It also shows why a named statistical endpoint is not enough to interpret evidence. A Pearson correlation can summarize the direction and strength of a linear association, but meaningful interpretation requires the numerical estimate, its uncertainty, the analysis denominator, and information about measurement and assumptions. Those results and details are not reported in the registry record.
The registry’s mention of several outcomes raises a further statistical question: how were multiple analyses handled? A set of outcome names does not disclose whether a testing hierarchy or multiplicity adjustment was used. Likewise, enrollment does not reveal how many participants contributed to each analysis, and zero adverse-event denominators do not support a safety conclusion.
For clinical researchers, the central lesson is to distinguish biological rationale from estimable effects, and planning illustrations from observed evidence. Clear reporting of analysis populations, estimates, uncertainty, and multiplicity methods is essential for judging what a study can support. In this record, the scientific question is identifiable, but the numerical results needed to evaluate it are not reported.
13. 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 main limitation for interpreting this study is that the registry record does not report the numerical primary correlation, its confidence interval, or its p-value. It also does not report numerical results for the listed secondary outcomes. Consequently, the magnitude, direction, and precision of the findings cannot be evaluated.
The study is described as nonrandomized, with allocation not stated and arms that are not a like-for-like control comparison. The registered intervention is mechanical ventilation, even though the study rationale discusses dopamine. The record does not describe a dopamine-treatment comparison, so it does not support interpreting the study as a randomized test of dopamine.
Although enrollment is recorded as 46, the analyzed sample size for the primary endpoint and for each secondary outcome is not reported. Participant flow, missing-data handling, exclusions, covariate adjustment, and analysis populations are also not reported in the registry record. These omissions limit assessment of potential selection effects, precision, and reproducibility.
The registry lists multiple outcomes but does not report a multiplicity strategy. It does not provide details of assay validation, laboratory blinding, or checks of the assumptions underlying Pearson correlation. Finally, adverse-event entries show zero at-risk denominators and zero events, which do not permit a meaningful safety interpretation. These limitations concern what can be concluded from the registry record; they do not establish that unreported procedures or analyses did not occur.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: the Effect of Dopamine on Mechanical Ventilation Induced Lung Injury — NCT03317431.
- Registry record last updated 2018-10-22; status last verified 2017-03.
- Results first posted 2018-10-22.
- 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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17. Record Summary
The registry record identifies NCT03317431, titled “the Effect of Dopamine on Mechanical Ventilation Induced Lung Injury,” with the official title “the Mechanism of the Downregulation of Dopamine Receptor in Mechanical Ventilation Induced Lung Injury.” It lists Acute Lung Injury as a condition, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine as sponsor, enrollment of 46, and status completed. The study start date is 2017-03-20, and primary completion is recorded as 2017-10-22.
The listed intervention is mechanical ventilation in patients undergoing selective operation with general anesthesia. The primary outcome is the Pearson correlation between ventilation duration and DRD1 expression, with a stated timeframe of 20min-60min. Four secondary outcomes concern DRD2, TH, DDC, and Ac-a-tubulin. The record describes a nonrandomized study, does not state allocation, and notes that the arms are not a like-for-like control comparison. Numeric outcome results and analysis details are not reported in the registry record.