The Pre-ECPR score for predicting favorable neurological outcomes after extracorporeal cardiopulmonary resuscitation: protocol for external validation in the Prague OHCA trial cohort.

Aim: No clear consensus exists for extracorporeal cardiopulmonary resuscitation (ECPR) patient selection in refractory cardiac arrest. Evidence suggests that current binary criteria yield either low favorable outcome rates, when being liberal, or exclude potential survivors, when being restrictive. The Pre-ECPR score, which uses logistic regression to give a single predicted probability of favorable outcome (modified Rankin Scale 0-3), demonstrated significantly better discriminatory ability than the Extracorporeal Life Support Organization "Example of selection criteria for ECPR". This protocol outlines the methodology for external validation of the Pre-ECPR score using the ECPR-treated patients from the randomized Prague Out-of-Hospital Cardiac Arrest (OHCA) trial. Methods: The validation cohort comprises the 92 ECPR-treated patients of the Prague OHCA trial. The Pre-ECPR score incorporates eight predictors: age, no-flow time/initial rhythm combination, total cardiac arrest duration, signs of life, pupil dilation, end-tidal CO Conclusion: This external validation will indicate whether the Pre-ECPR score retains its predictive performance in an independent OHCA population. The results will provide essential evidence for its potential to improve ECPR patient selection beyond conventional binary selection criteria.