The OSIRIS ECPR Trial

ECPR for OHCA is a resource-intensive method and poses significant challenges for both prehospital and hospital systems. Recent meta-analyses have highlighted persisting uncertainties regarding the routine use of ECPR strategy for OHCA, emphasizing the need for further research.

The refractory OHCA trial is a multicenter, multinational, open-label, randomized trial with a 2:1 concealed allocation of refractory OHCA patients to ECPR-based approach versus CCPR approach.

ECPR-based approach is defined as advanced cardiac life support (ACLS) per current guidelines with aim to proceed to in-hospital or out-of-hospital veno-arterial extracorporeal membrane oxygenation (V-A ECMO) if (return of spontaneous circulation) ROSC is not achieved before the cannulation.

CCPR is defined as conventional ACLS per current guidelines without mechanical circulatory support (MCS) use until sustained ROSC is achieved or the patient pronounced dead.

This study was designed to test the hypothesis that invasive, ECPR-based approach when compared to CCPR:

• increases survival in selected adults with refractory OHCA.
• and can be successfully implemented in different cities and countries.

The study will include adults 18-70 years of age suffering refractory OHCA of presumed cardiac cause. Refractory OHCA is characterized as either 3 unsuccessful defibrillations in ongoing shockable rhythms or 10 minutes of ACLS without ROSC in the case of a non-shockable rhythm following the first or second defibrillation.

Inclusion criteria

• Age ≥18 and ≤ 70 years presumed or known
• Witnessed OHCA
• Bystander CPR provided
• Presumed cardiac or unknown cause
• An initial documented shockable rhythm of VF (ventricular fibrillation) or pulseless VT (ventricular tachycardia)
• Minimum of ≥ 10 min of ACLS without ROSC or at least ≥ 3 defibrillations in ongoing VF/pulseless VT
• Body morphology able to accommodate a mechanical chest compression device
• ECPR team and intensive care unit (ICU) capacity in the receiving center available
• Estimated transfer time from the scene to the hospital ≤ 30 minutes or to the scene ≤ 30 minutes
• Eligible for intensive care without restrictions or limitations

Exclusion criteria

• ACLS ≥ 30 minutes before randomization
• Known limitations in care or a Do Not Attempt to Resuscitate (DNAR) order
• Known severe disease making 90-day survival unlikely
• Known bleeding diathesis or acute or recent intracranial bleeding
• Known, obvious or suspected pregnancy
• Known pre-arrest severe cognitive dysfunction (mRS ≥ 4)
• Known hypothermia as a cause of cardiac arrest