Validation of Utstein-Based score to predict Return Of Spontaneous Circulation (UB-ROSC) in patients with out-of-hospital cardiac arrest

Background Prediction of probability of return of spontaneous circulation (ROSC) during out-of-hospital cardiac arrest (OHCA) is one of the biggest challenge in resuscitation science. The Utstein Based-ROSC (UB-ROSC) score has been developed to predict ROSC in OHCA’s victims. Aim of the study was to validate UB-ROSC score using two large Utstein-based OHCA registries: the SWiss REgistry of Cardiac Arrest (SWISSRECA) and the Lombardia Cardiac Arrest Registry (Lombardia CARe), northern Italy. Methods Consecutive OHCA of any etiology occurring between January 1 st , 2019 and December 31 st and registered in 2 large national registries were included in a prospectively designed validation study. For model validation, a model area under the ROC curve (AUC ROC) for discrimination, using 10-fold cross-validation was computed. The score was plotted against the survival to hospital admission. Results 14,715 patients were included in the study. A sustained ROSC was obtained in 3,151 patients (21%). Overall, UB-ROSC model showed a good discrimination (AUC 0.72, 95% CI 0.71-0.73). Shape of risk predicted by the model was almost linear and the model resulted well calibrated. In the low likelihood subgroup of UB-ROSC, only 9% of patients achieved a ROSC. This proportion raised to 35% for UB-ROSC score between −18 and 12 (OR 5.3, 95% CI 2.9-9.4, P<0.001). Finally, in 85% of patients with UB-ROSC values of more than or equal to 13 a ROSC was obtained (OR 52.1, 95%CI 15.6-173.0, P <0.001). Conclusions UB-ROSC score may represent a reliable tool to predict ROSC probability. Its application may help the decision-making process providing a realistic stratification of probability of ROSC achievement. Clinical perspectives What is new? - UB-ROSC is the unique Utstein-based score designed to help EMS staff to stratify patient’s probability of ROSC before treating the patient. - In this validation study, UB-ROSC score was verified in a cohort of more than 14,000 OHCA and confirmed a very high power in discrimination of ROSC probability - The score is very user-friendly and may be considered a helpful tool for EMS in the decision-making process when approaching OHCA victims. What are the clinical implications? - Sudden cardiac death is the leading causes of death worldwide and substantially contribute to loss of health and excess health system costs. - Development and validation of models to stratify probability of survival are increasingly necessary in the decision-making process, particularly in a pre-hospital setting, to offer a realistic expectation of survival and eventually to terminate resuscitation attempts.