Emergency total extracorporeal life support versus standard advanced cardiac life support with rescue extracorporeal membrane oxygenation for refractory out-of-hospital cardiac arrest: protocol for the ECLS-OHCA randomized trial

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) is a time-sensitive emergency associated with high mortality and substantial risk of neurological disability. Extracorporeal cardiopulmonary resuscitation (ECPR) using extracorporeal membrane oxygenation (ECMO) has been introduced for refractory cardiac arrest, but recent randomized controlled trials have reported conflicting results, and the benefit of ECPR implemented according to rigorously timed protocols remains uncertain. AIM: This trial evaluates whether emergency total extracorporeal life support (ECLS), with emphasis on expedited cannulation and active left ventricular (LV) unloading, improves 30-day survival with favourable neurological outcome compared with standard advanced cardiac life support (ACLS) with rescue ECLS in adults with refractory shockable out-of-hospital cardiac arrest. DESIGN, SETTING, AND PARTICIPANTS: This is a prospective, investigator-initiated, multicenter, open-label randomized clinical trial conducted in eight experienced extracorporeal membrane oxygenation (ECMO) centers in the Taipei metropolitan area. Eligible adults aged 18-75 years with witnessed refractory shockable OHCA (ventricular fibrillation or pulseless ventricular tachycardia) who received bystander cardiopulmonary resuscitation (CPR) are randomized 1:1 on emergency department (ED) arrival. INTERVENTIONS: Participants are assigned to: (1) emergency total ECLS, with initiation as soon as possible after randomization and within 60 min of the emergency call, or (2) standard ACLS with rescue ECLS, in which at least 15 min of standard ACLS is provided in the ED before ECLS is considered. Both groups receive immediate coronary angiography and percutaneous coronary intervention (PCI) when indicated, and active LV unloading is recommended according to prespecified criteria. PRIMARY ENDPOINT: Survival at 30 days with favorable neurological status, defined as a Cerebral Performance Category score of 1 or 2. CONCLUSION: The ECLS-OHCA trial will provide complementary randomized evidence on the impact of expedited time-to-flow and protocolized LV unloading on neurological outcomes in refractory shockable OHCA and will explore the cost-effectiveness of this strategy. TRIAL REGISTRATION: ClinicalTrials.gov: NCT06692075.