P039: Potential impact on receiving hospital of a prehospital triage system for refractory cardiac arrest: a simulation study

Abstract

Introduction: Extracorporeal cardiopulmonary resuscitation (E-CPR) has been used successfully to increase survival in patients suffering from out-of-hospital cardiac arrest (OHCA). However, few OHCA patients can benefit from E-CPR since this procedure is only performed in dedicated centers. Prehospital triage systems have helped decrease mortality from other acute conditions, by directly transporting patients to dedicated centers, often bypassing primary care centers. Our study aimed to quantify the possible impact of a prehospital triage system on the proportion of E-CPR eligible patients transported to E-CPR centers. Methods: We used a registry of adult OHCA collected between 2010 and 2015 from the city of Montréal, Canada. Included patients were adults with non-traumatic witnessed OHCA refractory to 15 minutes of resuscitation. Using this cohort, we created 3 scenarios in which potential E-CPR candidates could be redirected to E-CPR centers. We used strict eligibility criteria in our first pair (e.g. age <60 years old, initial shockable rhythm), intermediate criteria in our second pair (e.g. age <65 years old, at least one shock given) and inclusive criteria in our third pair (e.g. age <70 years old, initial rhythm ≠ asystole). These 3 scenarios were compared to their counterpart in which patients would be transported to the closest hospital. The proportions of patients who would have been transported to an E-CPR centers were compared using McNemar’s test. To obtain a power of 99%, expecting 1% of discordant pairs and using a unilateral alpha of 0.83% (after Bonferroni correction), we needed to include at least 1000 patients. Results: A total of 3136 patients (2054 men and 982 women) with a mean age of 69 years (standard deviation 15) were included. In each simulation, prehospital redirection would have significantly increased the proportion of patients transported to an E-CPR center (pair 1: 1.3% vs 3.8%, p<0.001; pair 2: 2.6% vs 7.3%, p<0.001; pair 3: 7.6% vs 29.8%, p<0.001). Conclusion: In an urban setting, a prehospital triage system could triple the number of patients with refractory OHCA who would have an access to E-CPR. This implies that centers with E-CPR capability should prepare themselves accordingly for such a system to effectively improve survival following OHCA.