Red Cell Transfusion–Associated Hemolysis in Cardiac Surgery: An Observational Cohort Study
Bibliographic record
Abstract
BACKGROUND: Red cell viability is impaired during storage, resulting in excess hemolysis during storage and after transfusion. As a result, transfusions may oversaturate the hemoglobin clearance pathways, resulting in cell-free hemoglobin and iron toxicity in susceptible patients, such as those undergoing cardiac surgery with cardiopulmonary bypass. To explore this hypothesis, we assessed the relationship of red cell transfusions with cell-free hemoglobin and transferrin saturation levels in a consecutive cohort of cardiac surgical patients. METHODS: Laboratory measures of hemolysis were obtained in consecutive cardiac surgical patients 15 to 30 minutes after bypass. Multivariable regression models controlling for important confounders were constructed to determine the independent relationship of red cell transfusions during bypass with cell-free hemoglobin and transferrin saturation levels post-bypass, analyzed as continuous variables (linear regression) and categorized at the 90th percentiles (logistic regression). RESULTS: Of the 543 included patients, 82 (15.1%) received red cell transfusions during bypass (median 1; interquartile range 1-2 units). Cell-free hemoglobin was detected in all patients (mean 11.3; standard deviation ± 9.3; 90th percentile 18 μmol/L), and transferrin saturations were relatively high (mean 41 ± 19%; 90th percentile 66%). After controlling for confounders, transfusions were not associated with cell-free hemoglobin (P > .25 in linear and logistic regression) but were directly associated with transferrin saturation levels (P < .001 in linear and logistic regression). Transfused patients had a 6.2-fold (95% confidence interval: 2.4-16.1) risk-adjusted increase in the odds of having high (>66%) transferrin saturation levels. CONCLUSIONS: The findings support the hypothesis that transfusion-related adverse events may be in part caused by the excessive hemolysis of transfused red cells, which can lead to acute iron overload and related toxicity. This suggests that strategies aimed at avoiding or mitigating transfusion-related acute iron overload may improve the safety of red cell transfusions.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".