Abstract 14096: Ischemic Postconditioning During Cardiopulmonary Resuscitation Normalizes Mitochondrial Function in a Porcine Model of Prolonged Cardiac Arrest
Bibliographic record
Abstract
Introduction: Mitochondrial dysfunction is a hallmark of prolonged ischemia, however it’s onset during cardiac arrest (CA) and reperfusion with cardiopulmonary resuscitation (CPR) has yet to be elucidated. In a porcine model of CA, ischemic postconditioning (IPC) during CPR increased neurologically intact survival. We hypothesized that reperfusion injury, as evidenced by mitochondrial dysfunction, develops during CPR and is rescued with IPC. We investigated the effect of CA, CPR, and IPC on mitochondrial function and viability. Methods: After 15 min of ventricular fibrillation, 30 animals were randomized to no CPR (VF, n=10), active compression decompression + impedance threshold device (ACD-ITD) CPR (Control, n=9), or ACD-ITD CPR + IPC (IPC, n=11). Aortic blood pressure and ECG were continuously recorded. IPC consisted of 3 cycles of 20 sec compression / 20 sec pause for the first 2 min of CPR. Cardiac mitochondria were isolated via differential centrifugation 4 min after initiation of CPR. Additionally, mitochondria were isolated from 6 animals that did not suffer CA (non-ischemic controls). Respiration and calcium retention capacity (CRC) were measured for complex I (pyruvate+malate) and II (succinate+rotenone) substrates. Respiratory control index (RCI) was calculated as the ratio of states 3 to 4 respiration. Data were compared with ANOVA. A p value < 0.05 was considered significant. Results: Coronary perfusion pressure was similar between groups during CPR. Compared to the non-ischemic group, VF resulted in decreased complex I and II RCI and decreased complex I CRC. Control CPR increased complex I and II RCI compared to VF but did not affect complex I CRC. IPC increased complex I and II RCI and complex I CRC compared to VF and Control to a level comparable with the non-ischemic group. Complex II CRC was unchanged between groups. Conclusion: Complex I and complex II RCI and complex I CRC are diminished during VF. Respiration is partially restored with standard CPR. IPC improved mitochondrial function to non-ischemic values as early as 4 min after initiation of CPR. These improvements were independent of changes in blood pressure, suggesting that initiation of CPR is a source of mitochondrial reperfusion injury and a critical time for intervention.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".