Effect of pH Management on Brain Perfusion during Retrograde Cerebral Perfusion
Bibliographic record
Abstract
This study was undertaken to determine the effects of different pH management strategies during retrograde cerebral perfusion on the relationship between retrograde perfusion pressure and brain tissue perfusion. Six pigs were subjected to an alpha-stat strategy and another 6 to a pH-stat strategy during hypothermic (15 degrees C) retrograde cerebral perfusion at perfusion pressures of 10 to 70 mm Hg, in increments of 10 mm Hg every 20 min. Regional cerebral blood flow was significantly higher in the pH-stat group than in the alpha-stat group. The cerebral blood flow peaked at perfusion pressures of 40-50 mm Hg (18.6% +/- 10.8% in the pH-stat group vs. 3.6% +/- 1.2% in the alpha-stat group). In both groups, the intracranial pressure remained below the critical level of 25 mm Hg, even at a retrograde perfusion pressure of 70 mm Hg. Cerebral lactate production was higher in the alpha-stat group than the pH-stat group during retrograde cerebral perfusion at pressures of 10-30 mm Hg. Compared to the alpha-stat strategy, the pH-stat strategy significantly improved brain tissue perfusion. With an open inferior vena cava, the optimal perfusion pressure seems to be 40-50 mm Hg.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 teacher head, 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".