Cooling Vest May Reduce Heat Stress During Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Cooling Vest May Reduce Heat Stress During Surgery (NCT04511208), a randomized na study. The primary outcome is Self-rated Thermal Comfort..

2. Clinical Question

This is a question about a subjective rating of thermal experience, rather than a direct measure of body temperature. The scale’s midpoint represents comfort; values on either side indicate a sensation toward cold or heat. Accordingly, a difference in average scores should be read in light of where each condition’s average lies on that scale, not simply as a higher score being better.

The registry description identifies two points on the 11-point scale as a clinically important difference. The posted group means are 4.4 with the vest and 6.6 without it; the posted repeated-measures analysis reports a difference of -2.2 for the listed groups. A separate unadjusted recalculation expresses the contrast as without vest minus cooling vest, or 2.2. These are opposite signs for the same direction of comparison, not conflicting descriptions of which mean is higher.

3. Trial Design

The registry record describes a randomized crossover trial with no masking. Rather than assigning participants to separate vest and no-vest groups for the entire study, the design has each surgeon perform operations under both conditions. The record describes four operations per surgeon and four possible treatment sequences: ABBA, BAAB, AABB, and BBAA. In each sequence, A denotes the cooling vest and B denotes no cooling vest.

The sequence descriptions vary the order in which vest and no-vest operations occur. The registry’s summary characterizes the planned design as uniform and strongly balanced for first-order carryover effects. In general, crossover designs can make within-person comparisons, but the treatment order and period can matter: conditions may differ across operations, and an earlier condition may potentially influence a later one. The record’s design description does not tell us exactly how the reported model accounted for period, sequence, or carryover.

Enrollment was 30, and the record lists the trial as completed. The primary outcome was assessed immediately after surgery, within 10 minutes. The record also describes temperature measurements with a sensor worn for a total of 90 minutes. It lists multiple other secondary measures, including cognitive performance, perceived workload, fatigue, and sweat-soaked clothing.

The reported primary and selected secondary analyses used a repeated measures linear model. This is consistent with analysis of observations that are related within a participant, as can occur when the same person contributes data under both conditions. The registry record does not report the detailed model specification, the handling of missing observations, or the analysis population. The planned sample-size justification and the trial’s original design assumptions are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

First Surgery

Second Surgery

Third Surgery

Forth Surgery

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 Self-rated Thermal Comfort., measured over Immediately after surgery, within 10 minutes.

The primary endpoint is surgeons’ self-rated thermal comfort immediately after surgery, while still gowned and within 10 minutes of completing the operation. Surgeons rate their experience on an 11-point Likert scale from 0 to 10. The endpoints are defined by the scale anchors: 0 represents extreme cold, 5 represents thermal comfort, and 10 represents extreme heat. The registry description says that two points on this scale would be considered a clinically important difference.

A self-rating captures the participant’s experience directly. This can be useful when the question concerns perceived comfort, which is not identical to a temperature reading. At the same time, the result is subjective and depends on how participants interpret and use the scale. The mean summarizes ratings across observations, but does not show how individual surgeons’ ratings varied or whether every participant experienced the same direction of change.

The posted results report a mean of 4.4 with the cooling vest and 6.6 without it. The sponsor’s repeated-measures analysis reports a mean difference of -2.2 for its listed comparison, while the unadjusted recalculation presents the contrast in the reverse order as 2.2. The sign therefore depends on which condition is subtracted from the other. The absolute difference is close to the registry’s stated two-point benchmark; interpreting it alongside uncertainty and the crossover analysis is important.

This endpoint does not, by itself, establish an effect on body temperature, cognitive performance, workload, or surgical performance. Those are separate outcomes, and results for some listed measures are not reported in the registry record.

7. Results Posted in the Registry

• Without Cooling Vest: mean 6.60 versus 4.40 on control; difference 2.20 (95% CI 1.67 to 2.73), standardized effect d = 2.11; z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Mean Core Temperature.

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Without Cooling Vest: mean 33.20 versus 32.90 on control; difference 0.30 (95% CI 0.05 to 0.55), standardized effect d = 0.61; z-test p = 0.018.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Without Cooling Vest than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Mean Skin Temperature

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Without Cooling Vest: mean 36.30 versus 36.10 on control; difference 0.20 (95% CI -0.16 to 0.56), standardized effect d = 0.28; z-test p = 0.277.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Without Cooling Vest and the control. The interval gives the range of effects that remain compatible with the data.

Surgeon' Perceived Fatigue Measured as 0 Representing Not Fatigued at All, 5 Moderately Fatigued, and 10 Total Fatigue & Exhaustion

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Without Cooling Vest: mean 3.30 versus 2.30 on control; difference 1.00 (95% CI 0.29 to 1.71), standardized effect d = 0.72; z-test p = 0.006.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Without Cooling Vest than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The secondary outcomes with numerical results show a broadly aligned pattern in the posted summaries: the no-vest condition has higher reported values for the available temperature and fatigue measures. These outcomes relate to the primary question by adding measurements of body temperature and perceived fatigue alongside the surgeons’ own thermal-comfort ratings. They are related aspects of the study but are not interchangeable with the primary subjective endpoint.

The registry lists six secondary outcomes. Numerical results are posted for mean core temperature, mean skin temperature, and perceived fatigue. Results for cognitive performance, perceived ergonomic workload, and sweat-soaked clothing are not reported in the registry record. As a result, the complete secondary-outcome picture cannot be assessed from the record, and no conclusion about those unreported outcomes is warranted.

Secondary analyses generally carry less weight than the primary analysis in interpreting a trial, especially when several outcomes are examined. General statistical explanation: testing multiple outcomes creates more opportunities for a result to appear noteworthy by chance. Without a stated multiplicity plan or adjustment, an individual secondary p-value should be treated as exploratory rather than as an independent confirmation of the primary finding. The registry record does not report a multiplicity adjustment.

The secondary results can help describe whether other measured domains move in a similar direction, but they do not prove a common mechanism or establish effects on outcomes whose results are absent. The record also does not provide enough information to assess how secondary measures were handled in the repeated-measures model or whether all planned outcomes were analyzed. These reporting limits matter when considering the coherence and strength of the overall evidence.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Mean Core Temperature.
• Mean Skin Temperature
• Surgeons' Cognitive Performance, Measured With the C3B Battery.
• Surgeon' Perceived Ergonomic Workload Measured With the Borg Rating of Perceived Exertion (RPE) Scale.
• Surgeon' Perceived Fatigue Measured as 0 Representing Not Fatigued at All, 5 Moderately Fatigued, and 10 Total Fatigue & Exhaustion
• Surgeons' Perception and Amount of Sweat-soaked Scrub Clothing.

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: it is a numerical rating on a scale, and the registry reports means and standard errors. General statistical explanation: a mean describes the average of the recorded values, while a standard error describes the estimated uncertainty in that mean. A standard error is not the same as the spread of individual participants’ ratings. The primary results list a mean of 4.4 for the vest condition and 6.6 for no vest, with a standard error of 0.19 in both conditions.

What does the mean difference express?

A mean difference compares the averages in two conditions. Its sign depends on subtraction order. The reported sponsor analysis lists the groups in cooling-vest then no-vest order and reports -2.2. The simple recalculation instead expresses no vest minus cooling vest and reports 2.2. These estimates describe the same directional contrast using reverse subtraction. For this scale, the higher mean is toward the warm end, and 5 is the anchor for thermal comfort.

The reported analysis is a repeated-measures linear model. General statistical explanation: repeated-measures methods are designed for data where observations from the same participant are related, rather than independent. That relationship matters in a crossover because a participant contributes observations under both conditions. The registry record names the model but does not report its full specification. Details such as which period or sequence terms were included, how within-participant correlation was handled, and how potential carryover was assessed are not reported in the registry record.

How should the confidence interval and p-value be read?

The sponsor’s 95% confidence interval for its reported difference is -2.7 to -1.7. The unadjusted recalculation, expressed in the reverse direction, has a 95% confidence interval from 1.673 to 2.727. General statistical explanation: a confidence interval gives a range of estimates compatible with the observed data under the method used. It reflects statistical uncertainty, not the full range of outcomes for individual surgeons, and it does not account for design limitations that the analysis may not address.

The sponsor reports p < 0.001. General statistical explanation: a p-value describes how incompatible the observed data are with a specified null model, under the assumptions of the analysis. It is not the probability that the null hypothesis is true, nor a measure of clinical importance. A small p-value does not remove concerns about study design, missing data, or the analysis model. The registry record does not report whether the p-value was adjusted for testing multiple outcomes.

For continuous outcomes, the unadjusted recalculations compare posted group summary statistics. They do not replace the sponsor’s repeated-measures analysis and do not reproduce all features of the crossover design. As there is no discrepancy flagged between the sponsor result and the recalculation, the two can be read as broadly consistent in direction, while recognizing that the methods and subtraction order differ. When both are available, the sponsor’s own analysis is the trial’s reported inferential result.

Why does over-dispersion matter in some analyses?

General statistical explanation: over-dispersion occurs when observed variability is greater than a model assumes. If it is not accounted for, uncertainty estimates can be too small and intervals or tests can appear more precise than warranted. The outcomes are reported as continuous measures analyzed with a repeated-measures linear model; over-dispersion is not identified as an issue in the registry record. There is no basis in the record to claim that it was assessed or that a particular adjustment was used.

What does the crossover structure add?

In general, a crossover can compare conditions within the same participant, potentially reducing the influence of stable differences between participants. It also means that observations are not simply independent groups: operation period, order, and possible carryover can affect comparisons. The registry describes four sequences and states that the design was balanced for first-order carryover, but the reported analysis details do not establish how each of those design features was incorporated into the final model. The original sample-size justification and statistical plan are not reported in the registry record.

The planning illustrations accompanying the results use the stated observed effect, equal allocation, a two-sided significance level of 0.05, and a normal approximation. They describe hypothetical planning needs under those assumptions and are not a retrospective measure of the study’s probability of detecting an effect. The trial’s own original design assumptions are not reported in the registry record.

11. Confidence Intervals and Precision

The sponsor’s 95% confidence interval for the primary repeated-measures estimate runs from -2.7 to -1.7. The simple recalculation presents the contrast in the opposite direction, with a 95% confidence interval from 1.673 to 2.727. The signs differ because the subtraction order differs; both intervals describe a contrast in which the no-vest mean is higher than the cooling-vest mean. The sponsor’s estimate is the result from the trial’s reported model, whereas the recalculation is an unadjusted comparison based on posted summary statistics.

General statistical explanation: a confidence interval conveys the precision of an estimated average contrast. A narrower interval indicates less statistical uncertainty under the analysis assumptions; a wider one indicates more. The interval is not a guarantee that the true value lies within its limits, and it does not represent the range of individual participants’ ratings. It also cannot account for uncertainties arising from design or reporting details that are not available.

The primary endpoint description identifies two points as a clinically important difference. The confidence intervals give context for how precisely the average contrast was estimated relative to that stated benchmark. The interval from the sponsor’s analysis does not cross zero, and the unadjusted interval is likewise entirely above zero in its chosen direction. Statistical evidence for a nonzero average contrast and the clinical interpretation of its size are distinct questions.

Because this is a crossover study, precision should ideally be understood through the reported repeated-measures analysis, which can reflect within-participant data structure. The registry record does not provide enough model detail to assess the interval’s sensitivity to period, sequence, carryover, or missing data. The posted means and standard errors alone cannot show the distribution of participant-level changes.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size table and curve are planning illustrations based on the observed effect, not the original trial’s design calculation. For these continuous outcomes, the figures are participants per arm, not total events. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect set at the listed fraction of the observed effect. The original sample-size justification and the trial’s own design assumptions are not reported in the registry record.

The 80% power column gives the estimated participants per arm under those assumptions for a design with an 80% chance of detecting the specified effect if that effect were the true one. The 90% power column gives the corresponding planning number for a 90% chance. These are prospective planning interpretations of the table, not statements about the probability that this completed study detected an effect. This is not observed power.

The table varies the assumed effect: it includes the full observed effect, 75% of that effect, and 50% of that effect. The columns show that planning for a smaller effect requires more participants per arm to reach the same target power. For example, the primary-outcome table lists 4 participants per arm for 80% power at the full observed effect, and 15 per arm when planning for 50% of that effect. These illustrations follow the listed assumptions and should not be mistaken for the crossover trial’s actual design requirements.

The trial itself is a repeated-measures crossover, whereas the planning assumptions specify equal allocation between two arms. The registry record does not explain how the planning illustration relates to the original crossover design. The displayed figures therefore help show how required sample size changes with the assumed effect, but they do not establish that the trial was planned or powered using this calculation.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 2.200; pooled standard deviation σ = 1.041.
2. n = 2 × (1.96 + 0.842)² × 1.041² / 2.200² = 3.5, rounded up to 4 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 2.2                      # observed difference in means
sigma <- 1.04067285925982                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(4511208)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 4 (80% power), 5 (90% power)
 75% of observed effect: n per arm = 7 (80% power), 9 (90% power)
 50% of observed effect: n per arm = 15 (80% power), 19 (90% power)
power.t.test: 4.7 
Simulated power at n = 4 per arm: 0.701 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The sponsor reports a repeated-measures linear model for the primary outcome, with a difference in means of -2.2, a 95% confidence interval from -2.7 to -1.7, and p < 0.001. The listed groups are cooling vest and no cooling vest. The posted means are 4.4 and 6.6, respectively, so the negative estimate reflects subtraction in the listed order: cooling vest minus no cooling vest.

The recalculation shown alongside the results is a simple unadjusted comparison of the posted summary statistics. It expresses the difference in the reverse order, no cooling vest minus cooling vest, yielding 2.2, with a 95% confidence interval from 1.673 to 2.727 and p < 0.001. Reversing the order changes the sign, not the substantive direction of the contrast. The recalculation and the sponsor result are consistent in direction and close in magnitude, but they are not the same analysis: the sponsor’s model is repeated measures, while the recalculation is unadjusted.

There is no reported discrepancy between the two results. The sponsor’s own repeated-measures analysis takes precedence as the trial’s reported analysis, particularly because the trial uses a crossover design. The recalculation is useful as a transparent comparison based on posted summary values; it should not be treated as a replacement for the model or as a reconstruction of its full assumptions.

The registry record does not provide the detailed model specification or describe adjustments for period, sequence, or missing data. Those details cannot be inferred from the numerical agreement between the two estimates.

15. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome and six secondary outcomes. It also lists seven outcome measures and nine analyses. The primary endpoint is self-rated thermal comfort; the secondary list includes temperature, cognitive performance, workload, fatigue, and sweat-soaked clothing measures. The record does not report whether the investigators prespecified a hierarchy among secondary outcomes, a family of hypotheses, or an adjustment for multiple testing.

General statistical explanation: when several outcomes are tested, the chance of obtaining at least one apparently unusual result by chance can increase. Multiplicity procedures can control that risk, but the appropriate approach depends on the study’s goals and analysis plan. In the absence of a reported plan, the posted secondary p-values should be treated cautiously and should not be read as if each had been the sole primary test. Whether multiplicity was addressed is not reported in the registry record.

The record names a repeated-measures linear model for the primary and reported secondary analyses. It does not supply a full statistical analysis plan, specify every model term, or describe how sequence, period, or carryover were handled in the final analyses. The registry describes a balanced four-period crossover design, but that design description alone does not establish what adjustments appeared in the fitted model.

Missing-data procedures and analysis populations are also not reported in the registry record. Although the posted arm summaries list 30 observations for each condition, the record does not explain whether all enrolled participants contributed complete observations to every period and endpoint, how incomplete records were handled, or whether any participants were excluded from a particular analysis. It does not identify an intention-to-treat or per-protocol analysis population.

These omissions constrain appraisal of both multiplicity and potential bias. They do not establish that the investigators failed to address these issues; they mean that the registry record does not describe how they were addressed. The reported results can be summarized as posted, while these unreported elements remain open questions about the analysis.

16. Safety Results

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

Deaths

Other (non-serious) adverse events

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

The registry’s adverse-event figures list 30 participants at risk in each condition. It reports zero serious adverse events and zero deaths for the cooling-vest condition, and zero serious adverse events and zero deaths for the no-vest condition. It also reports zero other adverse events in both conditions. No serious adverse-event terms are listed.

These figures mean that the registry record reports no events in the listed categories during the recorded comparison. They do not establish that no event of any kind occurred outside the categories or reporting period represented in the record, nor do they show how events were defined, collected, or attributed. The record does not provide further details about the safety-monitoring process.

The adverse-event summary should be read as a description of the posted registry data, not as a comprehensive assessment of safety. The figures also do not address the study’s subjective comfort outcome or the other clinical and performance measures. No conclusion beyond the recorded event counts is supported by this summary.

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

The posted primary results describe higher average thermal-comfort scale scores without the cooling vest than with it. Because 5 represents thermal comfort and higher values move toward extreme heat, the averages indicate that the no-vest condition was rated farther toward heat on average. The sponsor’s repeated-measures model reports a difference of -2.2 for cooling vest minus no vest; the recalculation reverses the subtraction and reports 2.2. The confidence intervals and p-values indicate statistical evidence for an average contrast in the analyses reported.

The record identifies two scale points as a clinically important difference. The observed average contrast has a magnitude of 2.2, while the confidence intervals express uncertainty around that average. These values describe the group-level results and do not tell us how many individual surgeons experienced a particular change, whether all participants preferred one condition, or how ratings varied across operations.

The trial does not establish that the same results would occur across all surgeons, operations, environments, or work patterns. Participant and procedure characteristics are not reported in the registry record, and the study is described as having an enrollment of 30. The crossover design is useful for within-participant comparisons, but details of the final model and handling of incomplete observations are not reported.

The primary finding does not by itself establish effects on cognitive performance, ergonomic workload, or sweat-soaked clothing, for which outcome results are not reported in the registry record. The available temperature and fatigue outcomes are separate secondary measures and should not be conflated with the primary comfort rating. The posted event counts likewise do not support a broader claim about safety beyond the categories recorded.

This interpretation is statistical, not medical advice. It describes the outcomes and uncertainty recorded for this trial; it does not establish a treatment recommendation or a general conclusion about clinical practice.

18. Why This Trial Matters Statistically

This trial illustrates a useful statistical distinction between a subjective experience and a physiological measurement. The primary outcome is a rating of thermal comfort, while body temperatures are separate secondary outcomes. A change in one measure should not automatically be assumed to imply a change in another. Reporting the scale anchors also helps interpret direction: a higher score means warmer sensation, not necessarily greater comfort.

The crossover structure makes within-participant comparison central to the analysis. Such designs can account for stable differences between people, but they also make period, sequence, and carryover considerations important. The registry describes a carefully balanced sequence structure and reports a repeated-measures model, yet the model details needed to assess how the design was handled are not reported. This highlights why naming an analysis method is informative but not a substitute for a complete statistical description.

The example also shows why both an estimate and its uncertainty matter. The primary point estimate can be read against the scale’s stated clinical-importance benchmark, while the confidence interval conveys uncertainty around the average difference. A p-value alone would not convey the direction, size, or precision of the contrast.

Finally, the trial record demonstrates the importance of transparent reporting across outcomes. Several secondary measures are listed, but numerical results are not available for all of them, and no multiplicity approach is described. Readers can therefore distinguish the primary result from incomplete and exploratory secondary evidence rather than treating every listed outcome as equally conclusive.

19. 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 registry record provides limited information about who participated and the operations performed. Apart from the enrollment of 30 and the description of surgeons, participant characteristics, operation types, and relevant context are not reported. This makes it difficult to assess how broadly the results may apply.

The design is unmasked, so participants knew whether they were wearing a cooling vest. The primary endpoint is self-rated, and awareness of the condition could influence ratings. This does not establish that ratings were biased, but it is relevant when interpreting a subjective outcome.

The registry describes four sequences and a repeated-measures linear model, but the detailed model specification is not reported. How period, sequence, carryover, or within-participant correlation were handled cannot be assessed from the record. Nor are missing-data procedures or the analysis population reported. The posted summaries alone do not reveal whether all participants contributed data to every period and outcome.

Numerical results are not reported for three listed secondary outcomes: cognitive performance, perceived ergonomic workload, and sweat-soaked clothing. The record does not describe a multiplicity adjustment, so the secondary results that are available should be interpreted cautiously. The trial’s own sample-size justification and original design assumptions are also not reported; the accompanying planning illustrations are based on observed effects and are not the trial’s original design calculation.

Finally, the safety summary records no events in its listed categories but gives limited detail about event collection and definitions. These reporting limitations do not establish that the study was conducted inadequately; they define what can and cannot be evaluated from the registry record.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Cooling Vest May Reduce Heat Stress During Surgery — NCT04511208.
• Registry record last updated 2022-07-28; status last verified 2022-07.
• Results first posted 2022-07-28.
• 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.

23. Record Summary

The registry record describes a completed, randomized, unmasked crossover trial comparing operations with and without a cooling vest. Enrollment was 30, and the design description specifies four operations per surgeon arranged in one of four treatment sequences.

The primary outcome was thermal comfort rated from 0 to 10 immediately after surgery. Posted means were 4.4 with the vest and 6.6 without it. The sponsor’s repeated-measures analysis reported a difference of -2.2, with a 95% confidence interval from -2.7 to -1.7 and p < 0.001. A simple recalculation expresses the contrast in reverse order as 2.2, with a 95% confidence interval from 1.673 to 2.727.

Numerical results are available for three secondary outcomes; the registry record does not report results for the other three listed secondary measures. It reports zero serious adverse events, other adverse events, and deaths in both conditions. Detailed model specifications, missing-data procedures, multiplicity handling, and the original sample-size justification are not reported in the registry record.