The Effects of Simultaneous Antegrade/Retrograde Cardioplegia on Cellular Volumes and Energy Metabolism
Bibliographic record
Abstract
BACKGROUND AND AIM OF THE STUDY: Simultaneous antegrade/retrograde cardioplegia (SARC) has been employed frequently during cardiac surgery to preserve the jeopardized myocardium. However, retrograde perfusion of SARC may interfere with myocardial drainage and disrupt myocardial fluid homeostasis, which may affect the myocardial energy metabolism and contractile function. The study was, therefore, designed to assess the effects of SARC on myocardial fluid homeostasis, cellular volumes, and energy metabolism. METHODS: Eight isolated pig hearts were subjected to a protocol consisting of a 20-minute control perfusion, 120-minute SARC, and 20-minute reperfusion. The myocardial water content was monitored using near-infrared spectroscopy. Phosphorus-31 magnetic resonance ((31)P MR) spectroscopy was used to monitor the volumes of both intracellular and extracellular compartments and assess myocardial energy metabolism. RESULTS: The near-infrared spectra showed that the 120-min SARC resulted in a 60 +/- 12% increase in the myocardial water content. (31)P MR spectra showed a 36 +/- 4% increase in the intracellular compartment and a 54 +/- 8% increase in the extracellular compartment during SARC relative to their initial volumes measured during control perfusion (100%). However, the myocardial energy metabolites (adenosine triphosphate [ATP] and phosphocreatine [PCr]) remained unchanged during the 120-minute SARC. Moreover, during reperfusion, the hearts showed an almost complete recovery in the left ventricular-developed pressure. CONCLUSIONS: A prolonged SARC resulted in water accumulation in both extracellular and intracellular compartments in the normal myocardium. Although its detrimental effect on tissue fluid homeostasis did not jeopardize the myocardial energy metabolism, a prolonged use of SARC should be avoided, particularly in the diseased hearts.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| 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".