3 CPR by first responders improves acid-base balance and prognosis in out-of-hospital non-traumatic cardiac arrest
Bibliographic record
Abstract
Background Early basic-CPR has been shown to be effective. However, its effect on homeostasis in non-traumatic out-of-hospital cardiac arrest (OHCA) is unknown. We analyze pathophysiological and prognostic consequences of basic-CPR performed by first responders (FR) previous to EMS arrival. Method Prospective observational cohort study including all patients treated for OHCA by an EMS from 2015 to 2017. Basic-CPR by FR and venous blood gas by Epocal (Ottawa, Canada) at the beginning of advanced-CPR were covariates. Dependent variables included analytical values and final outcomes (ROSC and final neurological condition CPC grades I–II). Statistical analysis: Kolmogorov-Smirnov/Lilliefors test of normality, bivariate (T-test and Chi-square-test) and multivariate (logistic regression and recursive partitioning) analysis and association measures (odds ratio-OR). Results Our EMS attended 749 OHCA. Eighty-seven cases were excluded due to lack of data on gasometry (52)/FR (35). We analyzed 662 cases (137 women, 65.1±16.1 years-old), 46.1% were shockable rhythms and 63% received basic-CPR. pH was 7.13±0.15 in CPR-by-FR-cases and 7.06±0.18 in non-CPR-by-FR-cases (p<0.001). PvCO2 69±23 vs 77±25 mmHg (p<0.001), base excess −6.6±5.4 vs −8.6±6.6 mmol/L (p<0.001) and lactate 6.4±2.9 vs 7.1±3.3 mmol/L (p=0.008). CPR-by-FR (OR 1.83, CI95% 1.30–2.56, p<0.001) and shockable-rhythm (OR 3.32, CI95% 2.37–4.65, p<0.001) were independently associated with higher pH. ROSC occurred in 62.8% of CPR-by-FR-cases and 54.7% of non-CPR-by-FR-cases; OR 1.40, CI95% 1.02–1.93, p=0.039). Recovery CPC I–II occurred in 27.1% of CPR-by-FR-cases and 19.2% of non-CPR-by-FR-cases; OR 1.57, CI95% 1.06–2.30, p=0.022). Conclusion Basic-CPR by FR slows down metabolic and respiratory acidosis. This entails better outcomes. These data reinforce universal CPR training programs. References Shin J, Lim YS, Kim K, Lee HJ, Lee SJ, Jung E, et al. Initial blood pH during cardiopulmonary resuscitation in out-of-hospital cardiac arrest patients: a multicentre observational registry-based study. Critical Care 2017;21:322. Corral E, Casado MI, García-Ochoa MJ, Suárez R. Looking a ‘metabolic watch’. The analytical parameters found at the beginning of the resuscitation are predictors of the neurological prognostic in the prehospital cardiac arrest. Resuscitation 2015;96(Suppl 1);148. Conflict of interest None. Funding None.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.003 | 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".