Prehospital study of survival outcomes from out-of-hospital cardiac arrest in ST-elevation myocardial infarction in Queensland, Australia (the PRAISE study)

Abstract

Abstract Aim Patients that experience an out-of-hospital cardiac arrest in the context of a paramedic-identified ST-segment elevation myocardial infarction are a unique cohort. This study identifies the survival outcomes and determinants of survival in these patients. Methods A retrospective analysis was undertaken of all patients, attended between 1 January 2013 and 31 December 2017 by the Queensland Ambulance Service, who had a ST-segment elevation myocardial infarction identified by the attending paramedic prior to deterioration into out-of-hospital cardiac arrest. We described the ‘survived event’ and ‘survived to discharge’ outcomes of patients and performed univariate analysis and multivariate logistic regression to identify factors associated with survival. Results In total, 287 patients were included. Overall, high rates of survival were reported, with 77% of patients surviving the initial out-of-hospital cardiac arrest event and 75% surviving to discharge. Predictors of event survival were the presence of an initial shockable rhythm (adjusted odds ratio 8.60, 95% confidence interval (CI) 4.16–17.76; P < 0.001) and the administration of prehospital medication for subsequent primary percutaneous coronary intervention (adjusted odds ratio 2.54, 95% CI 1.17–5.50; P = 0.020). These factors were also found to be associated with survival to hospital discharge, increasing the odds of survival by 13.74 (95% CI 6.02–31.32; P < 0.001) and 6.96 (95% CI 2.50–19.41; P < 0.001) times, respectively. The administration of prehospital fibrinolytic medication was also associated with survival in a subgroup analysis. Conclusion This subset of out-of-hospital cardiac arrest patients was found to be highly salvageable and responsive to resuscitative measures, having arrested in the presence of paramedics and presented with an identified reversible cause.