Speaker abstracts
Bibliographic record
Abstract
The age of stored erythrocytes has been implicated as a potential etiology of several adverse clinical outcomes: immunomodulation, transfusion-associated lung injury, multiple organ failure; and lack of efficacy: failure to provide adequate tissue oxygenation.The latter is based on two physiological changes occurring with erythrocyte storage.Erythrocyte concentrations of 2,3-diphosphoglycerate (2,3-DPG) decrease with duration of storage, and reach depleted concentrations of 1 lmol/g hemoglobin or less at 21 days of storage.1-3 2,3-DPG is an important determinant of the affinity of hemoglobin for oxygen, with affinity increasing (P50 decreasing) as 2,3-DPG decreases 4,5 (and thus, as erythrocyte storage age increases).This has led some to postulate that transfused stored erythrocytes bind oxygen too tightly to allow for oxygen release at physiologic conditions 6 until 2,3-DPG increases, some hours after transfusion.2,3,[6][7][8] The second potential biophysical basis for the putative lack of immediate efficacy of transfused stored erythrocytes is that erythrocytic concentrations of adenosine triphosphate (ATP) decrease with storage duration.Decreased erythrocyte ATP concentrations have been associated with decreased erythrocyte deformability and in vivo survival secondary to impaired ability of erythrocytes to pass the microcirculation.9,10 However, this hypothesis has been questioned by more recent data using laser technology.11,12 Other studies in humans either have not been prospective and randomized, or have not tested humans using an appropriately sensitive measure when the subjects were in an oxygendependent state.We utilized our model of severe acute anemia, 13 in which cognitive function 14,15 and central neurophysiologic function as assessed by P300 16 are oxygen-delivery dependent, to test this hypothesis.With institutional approval and subjectsÕ informed consent, we studied nine volunteers (sample size determined by a priori power analyses) made acutely isovolemic anemic to a hemoglobin concentration of 50 g/L on two separate days, separated by 7 days.Cognitive function was tested with a computerized digit-symbol substitution test (DSST) each day before induction of anemia, at hemoglobin concentrations of 7 g/dL and 5 g/dL, and after transfusion of autologous erythrocytes, either stored for 3 h (ÔfreshÕ) or stored at usual blood bank conditions for 3 weeks, in sufficient quantity to increase the hemoglobin concentration to 7 g/dL.The type of erythrocytes transfused on each volunteer's first experimental day was randomly allocated; the alternate type of erythrocytes was transfused on the second experimental day.The subject and the person administering and evaluating the DSST were blinded as to type of erythrocyte transfused.Three weeks of storage reduced 2,3-DPG concentration from a normal value of 11.9 (10.4-13.4)lmol/g hemoglobin [mean (95% confidence interval)] to 1.1 lmol/g (0.7-1.5) (P < 0.001); 3 h of storage did not significantly change 2,3-DPG concentration.The P50 of the erythrocytes stored for 3 weeks was reduced from 27.4 mmHg (26.7-28.1 mmHg) to 15.0 (14.6-15.4)mmHg, and differed significantly (P < 0.001) from the P50 of the transfused erythrocytes stored for 3 h: 25.0 (24.5-25.5)mmHg.The DSST did not differ on the two experimental days before induction of anemia.The degree of anemia induced did not differ between the two experimental days (P = 0.69).Acute isovolemic anemia impaired (slowed response) (P < 0.001) the DSST equivalently on the two
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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 | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.859 | 0.653 |
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; the direct Gemma label and the distilled Codex classifier agree on what is shown here.
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".