Study Revives Hope: Enhancing Survival in Cardiac Arrest with Extracorporeal CPR Prediction Model

Patients who experience successful restoration of spontaneous circulation within three defibrillation attempts while having shockable rhythms tend to have favorable survival rates post cardiac arrest. Conversely, if CPR continues for over 20 minutes, the likelihood of achieving a positive neurological outcome decreases significantly. To enhance survival in challenging cardiac arrest scenarios, extracorporeal CPR (ECPR) is being more commonly employed. Recent study aimed to develop and validate a prediction model, the Pre-ECPR score, for favorable neurological outcomes in patients undergoing Extracorporeal Cardiopulmonary Resuscitation (ECPR) by incorporating various predictors to improve patient selection. The research was a single-center study involving 120 normothermic ECPR patients treated between January 2010 and October 2021 without any specific interventions. The Pre-ECPR score included predictors like age, initial rhythm, cardiac arrest time, signs of life, pupil dilation, cerebral oxygen saturation, arterial pH, and end-tidal CO2, which collectively demonstrated an Area Under Curve (AUC) of 0.87 for favorable outcomes.

Comparison of Prediction Models

The study findings suggested that continuous predictors in the Pre-ECPR score outperformed the Extracorporeal Life Support Organization (ELSO) criteria in predicting favorable outcomes in ECPR patients, achieving a significantly higher AUC of 0.79 in internal cross-validation compared to 0.63 for ELSO criteria. A threshold probability of 6.4% in the Pre-ECPR score showed 100% sensitivity and a 40.5% positive predictive value for favorable outcomes. The predictors in the score, such as signs of life, pupil dilation, and cerebral oxygen saturation, demonstrated significant individual predictive abilities contributing to the model's performance.

Development and Validation of Pre-ECPR Score

The Pre-ECPR score was developed to provide a reliable and balanced prognosis of outcomes by combining multiple weighted predictors. The study highlighted the importance of considering key factors like initial rhythm, signs of life, pupil dilation, and cerebral oxygen saturation in improving patient selection for ECPR. While the Pre-ECPR score showed promising performance in predicting favorable outcomes and outperformed existing selection criteria, external validation with a larger sample size is necessary to further evaluate its generalizability and refine the ECPR selection instrument. The study also emphasized the importance of external validation to test the scores' applicability across different settings and populations for enhanced decision-making in ECPR patient selection.

Key Points

1. The study aimed to develop and validate a prediction model, known as the Pre-ECPR score, to predict favorable neurological outcomes in patients undergoing Extracorporeal Cardiopulmonary Resuscitation (ECPR) by incorporating predictors like age, initial rhythm, cardiac arrest time, signs of life, pupil dilation, cerebral oxygen saturation, arterial pH, and end-tidal CO2. The Pre-ECPR score demonstrated an Area Under the Curve (AUC) of 0.87 for favorable outcomes in a study involving 120 normothermic ECPR patients.

2. The Pre-ECPR score, with continuous predictors, outperformed the Extracorporeal Life Support Organization (ELSO) criteria in predicting favorable outcomes in ECPR patients. It achieved a significantly higher AUC of 0.79 in internal cross-validation compared to 0.63 for the ELSO criteria. Notably, a threshold probability of 6.4% in the Pre-ECPR score showed 100% sensitivity and a 40.5% positive predictive value for predicting favorable outcomes.

3. The development of the Pre-ECPR score aimed to provide a reliable prognosis by combining multiple weighted predictors such as signs of life, pupil dilation, and cerebral oxygen saturation. These factors were found to have significant individual predictive abilities, contributing to the overall performance of the model in predicting favorable outcomes for ECPR patients.

4. Key factors like initial rhythm, signs of life, pupil dilation, and cerebral oxygen saturation were emphasized in the Pre-ECPR score as crucial predictors for improving patient selection for ECPR. The study highlighted the importance of considering these factors in patient selection to enhance outcomes and improve decision-making in the context of ECPR.

5. Despite showing promising performance and outperforming existing selection criteria, the Pre-ECPR score requires external validation with a larger sample size to evaluate its generalizability and further refine the ECPR selection instrument. External validation is crucial to test the applicability of the score across various settings and populations to ensure its effectiveness in enhancing decision-making for ECPR patient selection.

6. The study ultimately underscores the significance of developing and validating prediction models like the Pre-ECPR score to improve patient outcomes and selection in the context of Extracorporeal Cardiopulmonary Resuscitation. By incorporating multiple predictive factors and demonstrating superior performance compared to existing criteria, the Pre-ECPR score represents a potential advancement in personalized medicine for ECPR patients.

Reference –

Bengt Redfors et al. (2024). The Pre-ECPR Score: Developing And Validating A Multivariable Prediction Model For Favorable Neurological Outcomes In Patients Undergoing Extracorporeal Cardiopulmonary Resuscitation.. *Journal Of Cardiothoracic And Vascular Anesthesia*. https://doi.org/10.1053/j.jvca.2024.09.009.