Near Infrared Spectroscopy (NIRS) as Transfusion Indicator in Neurocritical Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Near Infrared Spectroscopy (NIRS) as Transfusion Indicator in Neurocritical Patients (NCT00566709), a randomized phase 2 study. The primary outcome is Number of Units of Packed Red Blood Cell Transfused.

2. Clinical Question

3. Trial Design

The registry describes a randomized, parallel-group Phase II study with no masking. The study title is “Near Infrared Spectroscopy (NIRS) as Transfusion Indicator in Neurocritical Patients.” Its official title describes use of near infrared spectroscopy to optimize red-cell transfusion in neurocritical patients with severe traumatic brain injury, subarachnoid hemorrhage, or intracerebral hemorrhage. Hospitales Universitarios Virgen del Rocío is listed as the sponsor.

The registry records enrollment of 102 and marks the study as completed. The recorded start is 2009-06, and primary completion is 2009-11. The primary endpoint records 46 participants in the rSO2-based arm and 51 in the hemoglobin-based arm. These are the arm counts attached to that outcome; the registry record does not explain the relationship between those counts and total enrollment, or provide a participant flow account.

In the rSO2 strategy, transfusion was intended to attain a post-transfusion rSO2 value higher than 60%. In the hemoglobin strategy, transfusion was intended to reach post-transfusion hemoglobin levels between 8.5 g/dL and 10 g/dL. The registry identifies red-cell transfusion as the intervention. It does not report details such as allocation concealment, implementation of randomization, adherence to the assigned strategy, or how treatment decisions were handled when the target was not reached.

The study’s stated context is uncertainty about appropriate transfusion triggers in neurocritical care. Its summary contrasts hemoglobin-based thresholds with the possibility of using signals from the brain, including measurements obtained through non-invasive near infrared spectroscopy. The trial’s primary endpoint focuses on how many units were transfused, while the posted secondary outcomes include hospital mortality, intensive care stay, long-term mortality, and unfavorable Glasgow Outcome Scale. The registry record does not report the original statistical plan or the original design assumptions.

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

Reasons for not completing this period:

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: Patient included into to "Intention to treat" analysis

6. Primary Endpoint

The registry lists the primary outcome as Number of Units of Packed Red Blood Cell Transfused, measured over duration of the protocol, an average of 15 days.

The primary endpoint measures the number of units of packed red blood cells transfused over the period each patient was included in the protocol. The registry describes this period as the duration of the protocol, an average of 15 days. The reported summary is a mean and standard deviation for each strategy, so the endpoint is treated as a continuous measure rather than as a count of participants who did or did not receive transfusion.

This endpoint is relevant to the stated study question because the two strategies use different triggers to guide transfusion. Comparing the average number of units can indicate whether one strategy was associated with more or fewer transfusions during the protocol period. It is a measure of treatment exposure, not a direct measure of the patient’s neurological status or survival. A difference in transfused units would not, by itself, establish a difference in clinical benefit or harm.

The rSO2-based arm had a mean of 0.9 units, with a standard deviation of 1.1. The hemoglobin-based arm had a mean of 1.5 units, with a standard deviation of 1.4. The registry’s reported analysis gives a two-sided t-test p-value of 0.03. The unadjusted recalculation estimates the mean difference as 0.6 units, with a confidence interval from 0.101 to 1.099. Interpretation should account for the study’s size, the uncertainty around the estimate, and the fact that the registry does not report enough information to assess all aspects of endpoint collection or analysis.

7. Results Posted in the Registry

• RBCT Based on Hemoglobin Level Value: mean 1.50 versus 0.90 on control; difference 0.60 (95% CI 0.10 to 1.10), standardized effect d = 0.47; z-test p = 0.018.

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.

Hospital Mortality

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • RBCT Based on Hemoglobin Level Value: 9.8% (5/51) versus 6.5% (3/46) on control; risk difference 3.3 percentage points (95% CI -7.6 to 14.1), risk ratio 1.50 (0.38–5.94); unadjusted two-proportion z-test p = 0.557.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between RBCT Based on Hemoglobin Level Value and the control. The interval gives the range of effects that remain compatible with the data.

Length of Intensive Care Unit (ICU) Stay

• 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 deviations.
• Result:
  • RBCT Based on Hemoglobin Level Value: mean 20.41 versus 21.00 on control; difference -0.59 (95% CI -4.83 to 3.65), standardized effect d = -0.06; z-test p = 0.785.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between RBCT Based on Hemoglobin Level Value and the control. The interval gives the range of effects that remain compatible with the data.

Long-term Mortality

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • RBCT Based on Hemoglobin Level Value: 23.5% (12/51) versus 26.1% (12/46) on control; risk difference -2.6 percentage points (95% CI -19.8 to 14.7), risk ratio 0.90 (0.45–1.81); unadjusted two-proportion z-test p = 0.771.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between RBCT Based on Hemoglobin Level Value and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes add context about mortality and intensive care stay, but they do not establish a clear pattern of better or worse clinical outcomes for either strategy. The available estimates are uncertain, and their confidence intervals allow for differences in both directions. These results should be read alongside the primary finding about transfused units, rather than treated as an independent confirmation of it. A change in transfusion exposure does not necessarily imply a change in mortality or length of stay.

The record identifies unfavorable Glasgow Outcome Scale as a secondary outcome, but does not provide a numerical result for it in the posted secondary results. Detailed values for that outcome are therefore not reported in the registry record. The registry lists six outcome measures and six analyses overall, while the available secondary entries include three numerical outcomes. The record does not explain this difference in detail.

Secondary analyses generally carry less weight than a clearly specified primary analysis, particularly when several outcomes are examined. Each additional comparison creates more opportunity for an apparently notable result to occur by chance. The registry does not report a multiplicity adjustment or a pre-specified hierarchy for secondary outcomes. Their p-values and estimates should therefore be treated as exploratory evidence rather than as definitive tests of the study question.

The secondary outcomes are also not interchangeable. Mortality is a binary outcome, while intensive care stay is a continuous measure. Their scales and uncertainties differ, and a result on one does not directly summarize the others. The evidence across outcomes remains limited by the available event counts, the posted sample sizes, and the absence of detailed information about analysis populations and missing data.

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

• Hospital Mortality
• Length of Intensive Care Unit (ICU) Stay
• Long-term Mortality
• Unfavorable Glasgow Outcome Scale (GOS)

9. Statistical Interpretation

10. Statistical Methods Explained

What does the mean difference represent?

The primary endpoint is continuous, and the registry summarizes it with a mean and standard deviation. The unadjusted comparison is expressed as the mean in the hemoglobin-based arm minus the mean in the rSO2-based arm. With that orientation, a positive difference means the posted mean is higher in the hemoglobin-based arm. The estimate is 0.6 units, based on arm means of 1.5 and 0.9 units. This is a simple comparison of posted summaries; it is not an adjusted estimate controlling for other characteristics.

A mean provides a measure of the center of the observed values, while the standard deviation describes their spread around that mean. The standard deviations are 1.4 units in the hemoglobin-based arm and 1.1 units in the rSO2-based arm. A mean does not show whether observations are concentrated near the average or whether the distribution has a long tail. The registry does not post participant-level values or a distributional description, so the shape of the outcome cannot be assessed from these summaries.

How should the p-values be read?

The sponsor-reported primary analysis is a two-sided t-test, with p = 0.03. A t-test evaluates how compatible the observed difference in means is with a null model of no mean difference, under the test’s assumptions. A p-value is not the probability that the null hypothesis is true, nor does it measure the size or clinical importance of a difference. The registry does not report further details about the t-test implementation or any covariate adjustment.

The unadjusted recalculation gives p = 0.018. It is based on the posted group summaries and is not a replacement for the sponsor’s analysis. The two values are not identical, but the record marks the discrepancy flag as false. The sponsor’s value remains the registry-reported result, while the recalculation offers a transparent summary-based comparison.

What do the binary-outcome comparisons measure?

For hospital and long-term mortality, the posted comparisons include a risk difference. This expresses the event proportion in the hemoglobin-based arm minus the event proportion in the rSO2-based arm. A positive value corresponds to a higher observed proportion in the hemoglobin-based arm; a negative value corresponds to a lower one. The reported tests are corrected chi-squared analyses. A chi-squared test assesses whether the observed event counts are compatible with equal proportions under its assumptions. The registry does not describe what correction was applied.

For these outcomes, a risk difference is an absolute contrast, while the posted risk-ratio and odds-ratio estimates are relative contrasts. Relative measures can appear large or small depending on the underlying event frequency, and their uncertainty matters. None of these measures alone proves that a strategy caused an outcome. The group counts are limited, and the confidence intervals for the risk differences span values in both directions.

What assumptions underlie the planning illustrations?

The sample-size planning illustrations use a two-sided significance level of 0.05, equal allocation between the arms, and a normal approximation. They use the observed effect as a reference and consider detecting a stated fraction of that effect. These are planning assumptions for the illustrations, not the original trial design assumptions. The registry does not report the trial’s own sample-size justification or original assumptions.

For continuous outcomes, a standard comparison of means uses the observed variability as part of the calculation. For binary outcomes, the planning calculation depends on the event proportions. In either case, the required sample size grows when the effect to detect is smaller, all else held constant. These calculations are planning illustrations and should not be read as evidence about the trial’s achieved probability of detecting an effect.

More generally, variability affects precision: greater variation makes it harder to estimate a mean difference precisely from a fixed amount of information. For binary outcomes, sparse events can also lead to wide uncertainty. These principles help explain why a point estimate should be considered alongside its confidence interval rather than interpreted in isolation.

The registry identifies the primary analysis and gives reported tests for posted outcomes, but it does not report a complete statistical analysis plan. The handling of missing data, the analysis population, model diagnostics, and any pre-specified subgroup analyses are not reported in the registry record. The available calculations therefore describe the posted summaries and tests, not every analytical decision that may have been made during the study.

11. Confidence Intervals and Precision

The primary unadjusted mean difference is 0.6 units, with a confidence interval from 0.101 to 1.099. The interval gives a range of values compatible with the posted summary data under the assumptions of the calculation. Its limits are both above zero, indicating that this unadjusted interval does not include no mean difference. It does not express the probability that the true effect lies within the interval, and its confidence level is not reported in the registry record.

The interval has meaningful width relative to the point estimate. It is consistent with a range of possible differences rather than a single precise value. The direction is consistent with fewer transfused units on average in the rSO2-based arm, but the estimate alone does not establish the clinical importance of that contrast. The registry does not provide a threshold for what would count as an important difference in units transfused.

Precision is more limited for the secondary outcomes. The hospital mortality risk difference is 0.033, with a confidence interval from -0.076 to 0.141. The long-term mortality risk difference is -0.026, with a confidence interval from -0.198 to 0.147. Both intervals include zero and allow for differences in either direction. The intensive care stay mean difference is -0.59 days, with a confidence interval from -4.827 to 3.647, also spanning zero.

These intervals show why a non-significant comparison should not be treated as evidence of equivalence. The secondary estimates remain compatible with a range of possible effects. The record does not report equivalence margins or a non-inferiority framework. For all outcomes, uncertainty should be considered alongside the study’s randomized design, the posted sample sizes, and the limitations in the registry’s reporting.

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 planning figures are illustrations based on observed effects, not the trial’s original sample-size calculations. For the posted outcomes, the values are participants per arm for the stated power levels, rather than total participants. The planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set to the stated fraction of the observed effect. The registry’s original design assumptions are not reported in the registry record.

The 80% power column describes the number of participants per arm estimated to give an 80% chance of detecting the specified effect under the planning assumptions, if that effect were the true one. The 90% power column uses a higher target chance of detection and consequently requires more participants per arm. These are prospective planning quantities, not a description of what happened in the completed trial.

Each row scales the effect used for planning relative to the observed effect. Planning for 75% of the observed effect or 50% of the observed effect assumes a smaller difference to detect than planning for 100% of the observed effect. Smaller effects need more participants to distinguish them from random variation with the same target power. The displayed values can therefore rise substantially as the assumed effect gets smaller.

These calculations are not observed power. They do not measure the probability that this completed trial found a result, and they do not establish whether the trial was adequately designed. They are illustrative only: they use the posted effects and stated assumptions, which may not match the assumptions used when the trial was planned.

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 = 0.600; pooled standard deviation σ = 1.267.
2. n = 2 × (1.96 + 0.842)² × 1.267² / 0.600² = 70.0, rounded up to 70 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 <- 0.6                      # observed difference in means
sigma <- 1.26678208153781                     # 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(566709)
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 = 70 (80% power), 94 (90% power)
 75% of observed effect: n per arm = 125 (80% power), 167 (90% power)
 50% of observed effect: n per arm = 280 (80% power), 375 (90% power)
power.t.test: 70.9 
Simulated power at n = 70 per arm: 0.800 (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 registry reports a two-sided t-test for the primary comparison, with p = 0.03. The unadjusted recalculation from the posted summary statistics estimates a mean difference of 0.6 units and gives p = 0.018. The group means and standard deviations are also posted: 0.9 units with a standard deviation of 1.1 in the rSO2-based arm, and 1.5 units with a standard deviation of 1.4 in the hemoglobin-based arm.

The recalculation is a simple, unadjusted comparison of those summaries. It does not incorporate undocumented adjustments or choices that may have been used in the sponsor’s analysis. The registry does not provide enough methodological detail to explain why the p-values differ. The discrepancy flag is false, and the posted sponsor result is retained as the reported analysis. The recalculated estimate and interval are useful as a separate summary-based account, not as a correction to the sponsor’s result.

Both analyses concern the same primary endpoint and point toward a higher mean number of units in the hemoglobin-based strategy. Neither p-value should be interpreted as the probability that the observed difference arose by chance, or as a measure of clinical importance. The effect estimate and its uncertainty provide additional context for the reported test.

15. Multiplicity, Missing Data and Analysis Populations

The registry reports a primary endpoint and several secondary outcomes, but a plan for controlling the chance of false-positive findings across multiple comparisons is not reported in the registry record. The reported p-values for secondary outcomes are unadjusted in the posted results. When multiple outcomes are tested, interpreting each p-value as though it were the only test can overstate the strength of evidence. The registry does not report a hierarchy, gatekeeping procedure, or other multiplicity strategy.

The record does not report whether analyses followed an intention-to-treat population, a per-protocol population, or another analysis set. It also does not provide a participant flow account explaining the arm counts attached to the outcomes relative to the recorded enrollment. Reasons for missing outcome data, the extent of missingness, and methods used to handle missing data are not reported in the registry record. The posted numbers should therefore be understood as outcome summaries with no further information about the analysis population.

Other statistical-plan details are also absent. The original sample-size justification, interim analyses, covariate adjustment, subgroup analyses, and diagnostic checks are not reported in the registry record. The planning illustrations described for the posted results are not evidence of the study’s original design assumptions. Without the original protocol or a detailed analysis plan in the registry, it is not possible to establish which analyses were pre-specified.

These reporting gaps do not invalidate the posted results, but they limit independent assessment of how the analyses were selected and conducted. They also make it harder to distinguish planned analyses from exploratory ones. The randomized design is relevant to interpreting the comparisons, yet the record’s limited reporting leaves important questions about allocation implementation, adherence, and analysis populations unresolved.

16. 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.

The adverse-event record lists 51 participants at risk for serious events in each strategy group and 51 at risk for other events in each group. It records 0 affected for serious events and 0 affected for other events in both groups. The death fields are null, and death counts are not reported in the registry record. These fields are separate from the posted mortality outcome results.

The recorded zeros mean that the registry lists no affected participants in these adverse-event fields. They should not be treated as a complete safety assessment: the record does not provide event-term details, event collection procedures, severity definitions, or an explanation of how the at-risk counts relate to the outcome arm counts. No serious adverse-event terms are listed.

Absence of recorded events in these fields does not establish that the strategies have no risks. It only describes what the adverse-event record contains. The limited safety information should be interpreted cautiously, especially alongside the missing details about ascertainment and reporting.

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

The result indicates that the posted mean number of packed red-cell units was lower in the rSO2-based strategy than in the hemoglobin-based strategy during the protocol period. The unadjusted estimated difference is 0.6 units, with the hemoglobin-based arm higher, and the interval is from 0.101 to 1.099. The sponsor-reported test also points to a difference in the primary endpoint. These findings concern transfusion exposure under the strategies as described in the registry.

They do not show that the rSO2-based approach improves survival, neurological recovery, or other patient outcomes. Nor do they establish that the hemoglobin-based approach causes harm. The available secondary comparisons are uncertain, and the registry does not report numerical results for unfavorable Glasgow Outcome Scale. The primary endpoint is not a substitute for those clinical outcomes.

The findings also do not prove that a particular transfusion threshold is optimal. The trial compares the described strategy targets in its enrolled neurocritical population. The registry does not provide enough detail to judge how consistently the targets were achieved, how treatment decisions were managed, or whether results differed across the listed conditions. Findings should not be extended automatically to other transfusion protocols or patient groups.

A statistically notable comparison is not the same as a clinically important effect. The registry does not report a threshold for clinical importance in transfused units. The confidence interval communicates uncertainty around the estimated difference, while the trial’s design and incomplete reporting constrain broader conclusions. The result is best read as evidence about the primary transfusion-use endpoint, with unresolved uncertainty about clinical consequences and generalizability.

18. Why This Trial Matters Statistically

This trial addresses a statistical challenge in clinical research: a biological measurement used to guide care can be compared with a conventional laboratory threshold using a randomized design. The primary endpoint captures a direct consequence of those decision strategies—the number of packed red-cell units transfused—rather than relying only on a proposed mechanism or surrogate signal.

The randomized parallel-group structure supports a comparative interpretation of the assigned strategies, while the absence of masking is relevant because the intervention depends on clinical decisions. The registry does not describe adherence or implementation, so the extent to which the observed transfusion pattern reflects the assigned targets cannot be assessed fully from the record.

The trial also illustrates why outcome selection matters. A strategy may be associated with different use of a treatment without demonstrating a corresponding difference in mortality or neurological outcome. Reporting the primary endpoint alongside secondary outcomes helps separate a process-of-care result from evidence about patient outcomes. Here, the primary comparison is more informative about transfusion exposure than the secondary results are about clinical effects.

Finally, the record shows the importance of precision and transparent analysis. The mean difference has a confidence interval, while the sponsor-reported test and summary-based recalculation yield different p-values. The secondary estimates remain uncertain, and the record does not report multiplicity handling or several analysis-plan details. These features make the distinction between an observed estimate, its uncertainty, and a broader clinical claim especially important.

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 leaves several trial-specific limitations unresolved. The primary endpoint counts units transfused over the protocol period, described as an average of 15 days, but the record does not report participant-level distributions, the timing of individual transfusions, or how protocol exposure varied. Means and standard deviations alone cannot show whether a small number of participants accounted for much of the observed difference.

The study includes patients with traumatic brain injury, subarachnoid hemorrhage, and intracerebral hemorrhage. The record does not report the number or characteristics of participants in each condition, nor does it provide condition-specific results. The extent to which the overall estimate applies similarly across these clinical groups cannot be assessed.

The trial is unmasked, and the intervention strategies rely on clinical transfusion decisions. The registry does not report adherence to assigned targets, crossover, clinician discretion, or whether targets were reached. Those details matter for understanding how the strategies were delivered and what the primary outcome represents.

Further limitations are the absence of a participant flow account, baseline characteristics, missing-data methods, and a detailed statistical analysis plan. The registry does not report the original sample-size justification, multiplicity handling, or analysis populations. These omissions limit assessment of selection, balance, precision, and pre-specification. The adverse-event record contains zero affected entries but little detail about ascertainment, and death fields are not reported. Together, these gaps counsel caution when interpreting safety and extending the findings beyond the posted comparison.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Near Infrared Spectroscopy (NIRS) as Transfusion Indicator in Neurocritical Patients — NCT00566709.
• Registry record last updated 2016-04-19; status last verified 2016-03.
• Results first posted 2016-03-11.
• 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 records a completed, randomized, parallel-group Phase II study with no masking, sponsored by Hospitales Universitarios Virgen del Rocío. It compares transfusion guided by rSO2 with transfusion guided by hemoglobin levels in neurocritical patients with traumatic brain injury, subarachnoid hemorrhage, or intracerebral hemorrhage. Enrollment is recorded as 102.

The primary endpoint is the number of packed red-cell units transfused during the protocol period. The posted means are 0.9 units for the rSO2-based strategy and 1.5 units for the hemoglobin-based strategy. The sponsor-reported primary test has p = 0.03; the unadjusted recalculation estimates a mean difference of 0.6 units with a confidence interval from 0.101 to 1.099.

Secondary outcome estimates are uncertain, and several analysis and reporting details are not reported in the registry record. The primary result describes transfusion exposure; it does not by itself establish effects on clinical outcomes or safety.