Hemodynamic effects of low-dose bupivacaine spinal anesthesia for cesarean section: A randomized controlled trial
Bibliographic record
Abstract
Background: Spinal anesthesia is the most common technique for cesarean section. The conventional local anesthetic dose has been decreasing over time to 8–12.5 mg of bupivacaine. Lower doses of bupivacaine may be associated with reduced incidence of hypotension and other complications. This low dose also may be associated with improved maternal cardiac index (CI). We hypothesized that low dose spinal anesthesia using 4.5 mg bupivacaine would result in improved maternal CI when compared with conventional dose (9 mg) intrathecal bupivacaine.Methods: This randomized controlled trial included all healthy parturients presenting for elective cesarean section. In addition to standard monitors, an arterial line was placed for pulse contour cardiac output measurement. Due to limited data on maternal cardiac output during cesarean section, we had to power our study on recovery room length of stay. Secondary outcomes included the change in maternal CI, fluid administration, vasopressor usage, maternal satisfaction, and adequacy of surgical blockade and recovery time from motor and sensory blockade.Results: The low dose group had significantly faster motor recovery times (132 [122–144] versus. 54 [48–66] min conventional versus. low-dose, respectively, P < 0.01), and a shorter recovery room stay (92 ± 21 vs 70 ± 11 min, conventional vs. low-dose, respectively, P < 0.01, 95% CI -35 to -10 min). There was no difference in CI between the conventional dose and low dose spinal groups. Both groups had a drop in CI with spinal anesthesia. The low-dose group demonstrated equivalent surgical anesthesia and block onset times compared to the conventional group.Conclusions: Low-dose spinal anesthesia provides adequate surgical anesthesia, improved recovery time, but no difference in maternal cardiac index when compared to conventional dose spinal anesthesia.NCT02046697
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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 | 0.003 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.005 | 0.003 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.008 | 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".