P836Benzodiazepine-free cardiac anesthesia for reduction of delirium (B-Free): a two-centre pilot study to determine the feasibility of a multi-centre, randomized, cluster crossover trial
Bibliographic record
Abstract
Background: Postoperative delirium affects 15–30% of adult cardiac surgery patients and is associated with adverse outcomes. Intensive care unit (ICU) data suggest that benzodiazepines are linked to delirium. While the benefit of alternate forms of sedation after cardiac surgery have been studied, no trials have examined the impact of changes to intraoperative benzodiazepine use. Purpose: To determine the feasibility of a multicentre, randomized cluster crossover trial evaluating whether an institutional policy of limited intraoperative benzodiazepine administration (B-Free) during adult cardiac surgery was associated with a decrease in the incidence of postoperative delirium, when compared with a policy of “ad libitum” intraoperative benzodiazepine administration. Methods: We conducted a two-centre, pilot randomized cluster crossover trial with four-four-week crossover periods. We obtained research ethics board approval for waiver of individual patient consent in both sites; all patients undergoing cardiac surgery during the pilot period were studied. Each site was randomized to either the B-Free or ad libitum policy and then alternated between intervention arms during the remaining 3 crossover periods. Our feasibility outcomes were: 1) obtaining at least one postoperative Confusion Assessment Method (CAM) delirium evaluation in 95% of enrolled patients, 2) obtaining at least one CAM per 24h in the ICU in 90% of enrolled patients, and 3) to achieve adherence to each of the intervention arm policies in 80% of patients. In one site, we evaluated the incidence of intraoperative awareness using serial Brice questionnaires and blinded adjudication, aiming to demonstrate an incidence of intraoperative awareness during the limited benzodiazepine period of ≤2%.
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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 | 0.011 | 0.009 |
| Meta-epidemiology (narrow) | 0.003 | 0.001 |
| Meta-epidemiology (broad) | 0.005 | 0.003 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.003 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.004 | 0.003 |
| Insufficient payload (model declined to judge) | 0.007 | 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".