Abstract 287: What Is the Optimal Chest Compression Depth During Resuscitation from Out-of-Hospital Cardiac Arrest in Adult Patients?
Bibliographic record
Abstract
Introduction: The 2010 AHA/ILCOR recommendations suggested an increase in CPR compression depth for adults, with a target >50 mm and no upper limit. This target is based upon limited evidence and, hence, we sought to determine the optimal compression depth range for adult patients. Methods: We studied emergency medical services treated OOHCA patients from the Resuscitation Outcomes Consortium ROC PRIMED clinical trial and Epistry - Cardiac Arrest database for whom electronic CPR compression depth data were available, from June 2007 to December 2010. We calculated anterior chest wall depression in millimeters for each minute of CPR. We controlled for 10 covariates including compression rate and calculated adjusted odds ratios for survival to hospital discharge, 24-hour survival, and any return of circulation (ROSC). Smoothing splines were used to explore the relationship between average compression depth and outcome for all patients as well as men and women separately. Results: We included 9,142 adult patients from 9 U.S. and Canadian cities with these characteristics: mean age 67.5 years; male 64 %; bystander witnessed 44%; bystander CPR 42%; initial rhythms - VF/VT 24%, PEA 20%, asystole 49%, other non-shockable 6%; outcomes - ROSC 31.3%, 1-day survival 22.8%, survival to hospital discharge 7.3%. For all patients, mean compression rate was 108 per minute; mean compression fraction 0.68; mean compression depth 41.9 mm with ranges: <38 mm 37%, 38-51 mm 45%, >51 mm 18%. Adjusted odds ratios for survival to discharge, with depth >51mm as reference, were <38 mm - 0.69 (95% CI 0.53, 0.90) and 39-51 mm - 1.03 (0.81, 1.30). Results were similar for the intermediate outcomes of ROSC and 1-day survival. Covariate-adjusted spline curves revealed that the maximum survival was associated with a depth of 45.8 mm followed by a decline in survival by 50 mm (optimal interval 44-49 mm). We also found no differences in the spline curves between males and females. Conclusions: This study found that more than one-third of patients received very low compression depth. The optimal CPR compression depth for survival appears to be 46 mm (44-49) for both males and female adults but falls off after 50 mm. These findings conflict with the 2010 international guideline recommendations.
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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 | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.001 | 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 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".