High Spinal Anesthesia for Cardiac Surgery
Bibliographic record
Abstract
BACKGROUND: This double-blind, randomized, controlled trial examined the effect of high-dose intrathecal bupivacaine in combination with general anesthesia on atrial beta-adrenergic receptor function, the stress response, and hemodynamics during coronary artery bypass graft surgery. METHODS: Thirty-eight patients were randomized to either control (n = 19) or intrathecal bupivacaine (ITB) groups (n = 19). Patients in the ITB group received 37.5 mg intrathecal hyperbaric bupivacaine before induction of general anesthesia. Control patients received an injection of local anesthetic into the skin and subcutaneous tissues (sham spinal). Comparisons were made between groups with respect to atrial receptor desensitization and down-regulation, in addition to circulating catecholamines and hemodynamics. RESULTS: In patients with cardiopulmonary bypass (CPB) times in excess of 1 h, the ITB group had significantly less atrial beta-receptor dysfunction, as measured by maximal isproteronol, 50% maximal isoproterenol, sodium fluoride-stimulated activity, and zinterol stimulation assays of adenylyl cyclase activity (P < or = 0.02) and beta-adrenergic receptor density (P = 0.02). Serum epinephrine, norepinephrine, and cortisol concentrations were significantly lower in the ITB group, independent of CPB times (P < 0.0001, P < 0.001, and P < 0.05, respectively). ITB patients had a higher cardiac index and a lower pulmonary vascular resistance index in the post-CPB time period (P < 0.01 and P < 0.05, respectively). In the pre-CPB period, mean arterial pressure and systemic vascular resistance index were significantly lower in the ITB group. CONCLUSIONS: High-dose intrathecal bupivacaine, when combined with general anesthesia, resulted in less beta-receptor dysfunction and a lower stress response during coronary artery bypass graft surgery.
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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 | 0.000 |
| 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".