Measuring Intraabdominal Pressure, Lactic Acid, and Urine Output: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Measuring Intraabdominal Pressure, Lactic Acid, and Urine Output (NCT05070572), a registered phase not stated study. The primary outcome is Intraabdominal Pressure.

2. Clinical Question

The registry summary also describes a longer-term motivation: comparing pressure measurements during surgery with measurements from daily activities and strenuous movements, and considering associations with inguinal hernia recurrence. These are stated aims, not reported findings. The record does not report results for correlations, comparisons with activity measurements, or recurrence.

The clinical question is therefore primarily descriptive and measurement-focused. It is not a treatment comparison: the record does not identify a therapeutic intervention assigned against a control. It describes measurements collected in people undergoing an operation. Whether the device measurements were accurate or precise, and whether the measured variables were associated with one another, is not reported in the registry record.

3. Trial Design

This is a completed pilot study registered as NCT05070572. The record describes enrollment of 21 obese individuals undergoing laparoscopic inguinal hernia repair. Its stated focus is measuring intra-abdominal pressure, lactic acid and urine output, including maximum intra-abdominal pressure levels during surgery. The intervention listed is the Accuryn Monitoring System, categorized as a device.

The registry lists a start date of 2021-01-01 and a primary completion date of 2023-01-31. Its status is completed. The record does not describe a control arm or an allocation method. It is not a like-for-like controlled comparison, so the design should not be read as estimating a comparative effect between assigned groups.

The study is explicitly described as a pilot. The stated purpose is to explore measurements and correlations, and to determine an accurate and precise measure of intra-abdominal pressure during laparoscopic hernia surgery using the monitoring system. The summary further mentions possible comparisons with pressure measurements during daily activities and strenuous movements, and associations with hernia recurrence. The registry record does not report the protocol details for those comparisons or state that they were completed.

The record names Antonios Likourezos as sponsor. It lists one outcome measure and no analysis entries. A sample-size justification, formal statistical analysis plan, prespecified interim analyses, and details of analysis populations are not reported in the registry record. The enrollment figure alone does not establish the precision achieved or whether the pilot met a planned target. The design information supports a description of a small measurement-focused investigation, but not an inference about comparative efficacy.

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 Intraabdominal Pressure, measured over 2 hours.

The registered primary endpoint is intra-abdominal pressure, expressed in mmHg. It is defined as the maximum intra-abdominal pressure levels during surgery, with a timeframe of 2 hours. The planned summary parameter is the mean, with standard deviation as the measure of dispersion.

As general statistical context, a mean describes the central level of a continuous measurement, while a standard deviation describes how much individual measurements vary around that mean. For a maximum-pressure endpoint, the interpretation depends on how each participant's maximum is defined and how measurements are collected and summarized. The registry record does not report those operational details.

In general, pressure measurement during an operation may be relevant to understanding pressure changes in that setting. This study's stated measurement aim includes assessing the Accuryn Monitoring System and considering relationships with lactic acid and urine output. The registry record does not report a numeric mean, standard deviation, or other primary endpoint result. It also does not report evidence establishing measurement accuracy or precision, so the endpoint definition alone cannot show how the device performed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record defines a continuous primary measure and specifies the summary statistics intended for it: the mean and standard deviation. The endpoint is maximum intra-abdominal pressure during surgery, in mmHg, over a timeframe of 2 hours. No numerical endpoint estimate is reported. The methods discussion below explains general statistical concepts; it does not describe analyses confirmed as having been used in this study.

What does a mean describe?

In general, the mean is a measure of the center of a set of numerical observations. For a clinical measurement, it gives a compact description of the average level in the analyzed group. Its interpretation depends on what counts as one observation. Here, the record calls the endpoint maximum pressure levels during surgery, but does not report whether the summary was calculated from one maximum per participant or another unit of observation. That detail matters because repeated readings from one person are not independent observations in the same way as measurements from different people.

What does the standard deviation add?

In general, the standard deviation describes the spread of observations around their mean. It is not the same as the standard error or a confidence interval: those quantities concern uncertainty in an estimated mean, while the standard deviation describes variation among observations. The registry specifies standard deviation as the dispersion measure, but no value is reported. Without the actual mean and standard deviation, the pressure distribution and its variability cannot be assessed.

How should a measurement claim be evaluated?

In general, accuracy concerns closeness of measurements to an appropriate reference or true value, while precision concerns the consistency of repeated measurements. A mean and standard deviation can describe a distribution, but by themselves do not establish either accuracy or repeatability. Evaluating those properties generally requires a reference method, repeated measurements, or an explicit agreement or reliability analysis, depending on the question. The registry summary states an aim to obtain accurate and precise measurements using the Accuryn Monitoring System, but does not report the methods or results needed to evaluate that aim.

Measurement conditions also matter in general. Device placement, timing, calibration, participant position, and the rules used to identify a maximum can affect a pressure measurement. The registry record does not report these procedural details. Consequently, the endpoint name and timeframe are not enough to reproduce the measurement or assess whether measurement conditions were consistent.

What can a correlation establish?

In general, correlation describes the direction and strength of association between measured variables under a particular analysis. It does not, by itself, establish that one variable causes another. The study summary states an aim to look for correlations among intra-abdominal pressure, lactic acid and urine output. No correlation estimates, methods, or results are reported in the registry record. Without those details, the stated aim cannot be interpreted as evidence that the measures were associated.

Why do study design and uncertainty matter?

In general, a confidence interval gives a range of values compatible with an estimate under a statistical model and its assumptions. Its width helps describe precision. A p value, when tied to a stated hypothesis test, addresses how compatible data are with a null model; it does not measure the size or clinical importance of an effect. The record reports neither confidence intervals nor p values for the primary endpoint. It also does not report an analysis plan, a sample-size justification, or interim analyses. Those items should not be inferred from the pilot label or the enrollment figure.

Because no comparison group is described, this study should not be interpreted as a randomized comparison or as a controlled estimate of differences between groups. A within-group descriptive measurement can characterize observations if the results are available, but it cannot by itself separate a device-related effect from other influences. The registry record does not report an analysis population or explain how missing measurements were handled.

In general, over-dispersion occurs when observed variability exceeds what a statistical model assumes. It can make standard errors and confidence intervals too optimistic if the model does not account for the extra variation. This concept is relevant when a model is used for data with more variability than expected, but the registry does not report a model or an over-dispersion assessment for this study. It would therefore be inappropriate to assert that over-dispersion was present or that a particular adjustment was used.

Any planning illustrations based on an observed effect are not observed power and are not a description of the trial's original design. The registry record does not report a sample-size justification or confirm that such illustrations informed enrollment. Statistical concepts can clarify what reported estimates would mean, but they cannot substitute for unreported study results.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Inguinal Hernia Repair")
n   <- c(21)
m   <- c(25.58)
sp  <- c(8.15)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Inguinal Hernia Repair  21  25.580  8.150  21.870  29.290

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists one outcome measure, with intra-abdominal pressure as the primary endpoint, and no analysis entries. The study summary additionally names lactic acid, urine output, correlations among measurements, comparisons with activity-related pressure data, and possible associations with hernia recurrence as interests or aims. The record does not establish which of these were prespecified secondary endpoints or analyzed outcomes.

Multiplicity arises in general when several hypotheses or outcomes are tested: the chance of at least one apparently notable finding can increase as more tests are considered. Methods such as prespecifying a primary outcome, controlling an error rate, or treating secondary analyses as exploratory can help readers interpret multiple results. The registry record does not report a multiplicity strategy, a hierarchy of tests, or a statistical analysis plan. No claim about adjustment or lack of adjustment should be inferred.

Missing-data handling is also not reported in the registry record. The record does not state how many participants had usable measurements for each variable, whether any measurements were missing, why they might be missing, or how missing values were handled. Enrollment of 21 does not establish the analysis count for the primary endpoint.

The record does not define an intention-to-treat, per-protocol, or other analysis population. Since this is not described as a randomized comparison, those labels should not be assigned without documented criteria. The absence of analysis entries means the posted information does not permit evaluation of exclusions, protocol deviations, or sensitivity analyses. These omissions constrain interpretation of both the planned measurements and any broader exploratory aims.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

The adverse-event figures list the Inguinal Hernia Repair group with 21 participants at risk for serious events and 0 affected. The same group has 21 at risk for other events and 0 affected; deaths are recorded as 0. No serious adverse-event terms are listed among the top terms.

These figures are counts in the registry record. They should be read as the posted adverse-event summary, not as proof that no event could have occurred under any definition or observation period. The record does not report event-collection procedures, the observation window for safety, event definitions, or whether the figures represent all enrolled participants throughout follow-up. It also does not provide detail about the completeness of safety reporting.

In general, zero recorded events in a study does not establish that an event is impossible or that risk is absent. Small studies can provide limited information about uncommon events, and interpretation depends on how events were sought and recorded. These safety counts describe what the registry reports; they do not support a broader safety conclusion.

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

The record documents a completed pilot investigation of a measurement question: intra-abdominal pressure during laparoscopic inguinal hernia repair in obese individuals, using the Accuryn Monitoring System. It identifies the primary endpoint as maximum intra-abdominal pressure during surgery, expressed in mmHg and summarized by a mean and standard deviation over 2 hours. It also records enrollment of 21 participants.

Those details establish the study's focus and its intended endpoint, but they are not outcome findings. The registry record does not report the primary pressure estimate, its variability, or the number of participants whose data contributed to the estimate. It also does not report results for lactic acid, urine output, correlations, measurement accuracy, measurement precision, or recurrence-related aims.

Accordingly, the record does not show how high the maximum pressure measurements were, how much they varied, or how precisely the group mean was estimated. It does not establish whether the device agreed with a reference measurement or whether repeated measurements were consistent. It also does not show a relationship between intra-abdominal pressure and the other measurements. Lack of reported results is not evidence that an association or measurement difference was absent.

This is not a controlled treatment comparison. No comparator or allocation method is described, so the record cannot support a causal contrast between assigned interventions. The study may be useful as a pilot in the sense that its stated purpose is exploratory and measurement-focused, but the posted information does not describe what feasibility criteria were assessed or whether they were met.

The correct scope of interpretation is therefore narrow: the registry describes a completed pilot study, its population, device, and primary measurement objective. Numerical findings and the analyses needed to judge the measurement questions are not reported in the registry record. The adverse-event counts are also limited to the posted summary and should not be expanded into a general safety claim.

14. Why This Trial Matters Statistically

Measurement quality is central to studies that rely on physiological readings. If a measurement is not defined consistently, differences across people or settings can be difficult to interpret. This pilot's stated focus on intra-abdominal pressure during laparoscopic inguinal hernia repair therefore raises statistical questions about how a maximum is obtained, how much measurements vary, and whether readings are accurate and repeatable.

The registry summary connects these measurements with lactic acid and urine output, and describes interest in comparisons with pressures during daily activities and strenuous movements. These aims illustrate how measurement studies can motivate later research: first establish how data are collected and characterized, then examine associations or comparisons. The registry record does not report results that answer those questions, so the scientific value of the intended comparisons cannot be judged from the posted findings.

Statistically, the distinction between an aim and an estimate is important. A planned correlation does not show that two measures covary, and an intention to assess accuracy does not demonstrate agreement with a reference. Reporting estimates alongside uncertainty and clear measurement procedures would be needed to assess those claims. The record identifies a mean and standard deviation as the planned summary for its primary endpoint but does not give their values.

The study also illustrates the limits of pilot enrollment as a standalone statistic. A participant count provides context for the scale of a study, but does not tell readers the precision of a mean or the reliability of a device. Those judgments depend on observed data, measurement procedures, and analysis methods, which are not reported in the registry record.

For clinical researchers and biostatisticians, the distinction between completed status and available results is consequential. The record can locate the question and the population studied, while still leaving central quantitative questions unanswered. Clear reporting of the measurement process and the resulting estimates would allow a more complete statistical appraisal.

15. 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 principal limitation for interpreting this trial is that the registry record does not report numerical primary endpoint results. Although it specifies a mean and standard deviation for maximum intra-abdominal pressure, neither statistic is reported. There is no confidence interval or other uncertainty estimate for the primary endpoint.

The endpoint description does not explain the operational measurement procedure. The record does not state how the maximum was defined, how often readings were collected, how values were processed, or whether device measurements were checked against a reference. These details are particularly relevant because the study's stated purpose includes accurate and precise measurement.

The summary names lactic acid and urine output and describes intended correlation and comparison questions, but results for these aims are not reported in the registry record. The record also does not provide a recurrence analysis or the protocol details for comparing intraoperative pressure with measurements during daily activities or strenuous movements.

No control group or allocation method is described, limiting the record to a non-comparative interpretation. The registry does not report a sample-size justification, statistical analysis plan, interim analyses, analysis populations, missing-data methods, or multiplicity approach. It is also not reported in the registry record how many participants contributed data to each measure or whether any measurements were incomplete.

The adverse-event summary provides counts but not the collection methods, event definitions, or observation period. These reporting limitations do not establish that the study was conducted inadequately; they mean the posted information is insufficient to evaluate those features or to draw conclusions beyond the stated design and recorded counts.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Measuring Intraabdominal Pressure, Lactic Acid, and Urine Output — NCT05070572.
• Registry record last updated 2026-04-29; status last verified 2023-12.
• Results first posted 2026-04-29.
• 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.

19. Record Summary

NCT05070572 is a completed pilot study titled “Measuring Intraabdominal Pressure, Lactic Acid, and Urine Output.” It enrolled 21 obese individuals undergoing laparoscopic inguinal hernia repair and lists the Accuryn Monitoring System as its device intervention. The registry gives a start date of 2021-01-01 and a primary completion date of 2023-01-31.

The primary endpoint is maximum intra-abdominal pressure during surgery, in mmHg, with a 2-hour timeframe and mean and standard deviation as the planned summaries. The study summary describes broader aims involving lactic acid, urine output, correlations, measurement accuracy and precision, activity-related measurements, and hernia recurrence.

The registry record does not report numerical primary endpoint results, analysis entries, or findings for the broader aims. It lists 0 serious events, 0 other events, and 0 deaths among the group of 21 at risk for each event category.