Faculty Opinions recommendation of Epidural anaesthesia and survival after intermediate-to-high risk non-cardiac surgery: a population-based cohort study.
Bibliographic record
Abstract
BACKGROUND: Although epidural anaesthesia and analgesia have numerous benefits, their effects on postoperative survival are unclear. We therefore undertook a population-based cohort study to determine whether perioperative epidural anaesthesia or analgesia is associated with improved 30-day survival.METHODS: We used population-based linked administrative databases to do a retrospective cohort study of 259 037 patients, aged 40 years or older, who underwent selected elective intermediate-to-high risk non-cardiac surgical procedures between April 1, 1994, and March 31, 2004, in Ontario, Canada. Propensity-score methods were used to construct a matched-pairs cohort that reduced important baseline differences between patients who received epidural anaesthesia or analgesia as opposed to those that did not. We then determined the association of epidural anaesthesia with 30-day mortality within these matched-pairs.FINDINGS: Of the 259 037 patients, 56 556 (22%) received epidural anaesthesia. Within the matched-pairs cohort (n=88 188), epidural anaesthesia was associated with a small reduction in 30-day mortality (1.7%vs 2.0%; relative risk 0.89, 95% CI 0.81-0.98, p=0.02).INTERPRETATION: Epidural anaesthesia and analgesia were associated with a small improvement in 30-day survival, but this effect should be interpreted cautiously. The estimate had borderline significance, despite a large sample size. Its absolute magnitude was also small, corresponding to a number needed to treat of 477. Our study, therefore, does not provide compelling evidence that epidural anaesthesia improves postoperative survival. Nonetheless, our results support the safety of perioperative epidural anaesthesia when used for indications other than improving survival (eg, improving postoperative pain relief, preventing postoperative pulmonary complications). PMID: 18692893
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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 | 0.005 | 0.041 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.001 |
| Insufficient payload (model declined to judge) | 0.064 | 0.010 |
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".