Abstract P169: Patients with an AED Applied by a Bystander in a Public Setting have a Strikingly Higher Frequency of VT/VF Than Observed Cardiac Arrests in the Home
Bibliographic record
Abstract
Introduction: The overall incidence of ventricular tachycardia/ventricular fibrillation (VT/VF) as the first recorded electrical rhythm in out of hospital cardiac arrest (OOHCA) has declined from ~70% to ~25% over the last 30 years. This change has been attributed to primary and secondary prevention of cardiovascular disease and VT/VF. We evaluated whether the incidence of VT/VF as first recorded rhythm differed by location among bystander AED applied patients and EMS witnessed cardiac arrests. Methods: Prospective cohort study of non-traumatic cardiac arrest from December 2005 to April 2007 in the Resuscitation Outcomes Consortium database from 10 US and Canadian sites. The incidence of an initial shockable rhythm on AED or documented VT/VF was compared among bystander applied AED patients and EMS witnessed arrests in public versus private settings. Results: The first rhythm was known in 13,235 of 14,059 (94%) adult EMS-treated cardiac arrests. Of the 13,235 with known rhythms, 3436 (26%) had VT/VF. Among 1115 EMS-witnessed arrests, 61/161 (38%) had VT/VF in public settings and 224/954 (23%) in private settings. Similarly, for bystander AED applied in the private setting 39/114 (34%) were shocked. But, in contrast, 125/159 (79%) (P<.001 vs all other) were shocked by the AED in the public setting. Witnessed arrests in both the private setting (vs public) and in EMS witnessed cases (vs bystander AED applied) were more likely to occur in older subjects and females. After adjusting for age and gender via logistic regression models, a significant difference in the odds of having a shockable rhythm in public versus private location of arrest remained in EMS-witnessed arrests (P<0.005). The difference also remained in bystander AED applied arrests (P<0.001) after adjusting for age, gender, and bystander-witnessed status. Conclusions: The incidence of VT/VF is far greater in the public setting particularly for bystander witnessed AED applied arrests. Patients in the private home setting, even for EMS observed arrests, are far less likely to benefit from AED application than bystander witnessed patients in the public setting. CPR strategies may need to be tailored by arrest location.
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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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.009 | 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".