The clinical utility of an index of global oxygenation for guiding red blood cell transfusion in cardiac surgery
Bibliographic record
Abstract
BACKGROUND: This observational study explored the potential utility of oxygen extraction ratio (O2ER) as an adjunct to the hemoglobin (Hb) concentration for guiding red blood cell (RBC) transfusion decisions after cardiac surgery with cardiopulmonary bypass (CPB). STUDY DESIGN AND METHODS: Hb and O2ER measures were obtained before as well as 15 and 120 minutes after RBC transfusion episodes (defined as 1-2 RBC units given in succession after CPB, within 24 hr. of surgery). Changes related to RBC transfusions among patients with normal (30%) and elevated(>30%) pretransfusion O2ERs were analyzed. RESULTS: Of the 176 patients enrolled, 74 received RBC transfusions. Of these, 50 had data available for 62 transfusion episodes. Pretransfusion episode O2ER values were elevated in 27 cases and normal in 35(56%) cases. Among those who received transfusion for low Hb concentration, 43 percent (27/62) had normal pretransfusion O2ER values. While the posttransfusion O2ER values did not change in patients with normal pretransfusion O2ER values, they did decrease inpatients with elevated pretransfusion O2ER values (% change [+/-SD] at 15 and 120 min after transfusion was -5.2 +/- 7.8 and -3.8 +/- 8.0%, respectively; p < 0.05). CONCLUSION: If a normal O2ER in anemic patients with no evidence of organ dysfunction indicates adequate tissue oxygen delivery, then our findings suggest that incorporating O2ER into the transfusion decision will substantially reduce post-cardiac surgery RBC transfusions by allowing us to safely avoid transfusing this group of patients. Future studies are needed to assess the validity of this conclusion.
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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 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".