Abstract Body: Background: Since January 2022, our emergency medical center has operated a prehospital extracorporeal cardiopulmonary resuscitation (ECPR) system. The ECPR team is dispatched for suspected CPA cases. Criteria for ECPR on the scene include patients aged 65 or younger with an initial rhythm of shockable or PEA. Additionally, witness presence, bystander CPR, and blood gas analysis are considered. Due to the difficulty in obtaining accurate on-scene information, the Sign of Life (SOL) is crucial. Cannulation is performed in a mobile ICU under mechanical CPR, with ultrasound-guided cannulation as the first choice. Once ECMO is established, systemic O2/CO2 optimization using a gas blender and rapid initiation of targeted temperature management (TTM) at 34°C are performed. This is the only system in Japan systematically performing prehospital ECPR for all OHCA cases, known as the "Utsunomiya model."
Objective: To evaluate the outcomes and feasibility of prehospital ECPR at our facility in Japan.
Methods: This retrospective case series included patients who underwent prehospital ECPR between January 2022 and May 2024. The primary outcome was favorable neurological outcome, and secondary outcomes included 28-day survival and complications.
Results: The prehospital ECPR system responded to 113 calls, resulting in 14 cases where ECPR was performed (11 identified as CPA by dispatchers, and 3 as non-CPA). The average patient age was 59 years, 85.7% were male, 64.3% had witnessed arrests, and bystander CPR was performed in 71.4% of cases. SOL was present in 57.1%, with initial rhythms: shockable in 28.6%, PEA in 50%, and asystole in 21.4%. ECMO-related metrics included a no-flow time of 2.5 minutes and a low-flow time of 33 minutes. Cannulation was performed percutaneously under ultrasound guidance, with an average cannulation time of 9.5 minutes. Favorable neurological outcomes were achieved in 28.6% of cases, with a 28-day survival rate of 64.3% and a complication rate of 0%. Among cases with SOL, the 28-day survival rate was 87.5%, and favorable neurological outcomes were 50%. Of the four cases with favorable outcomes, one had a shockable rhythm, two had PEA, and one had asystole, all with SOL.
Conclusion: Prehospital ECPR is a feasible intervention within the Japanese emergency medical system, demonstrating promising outcomes. Further studies are required to optimize patient selection and procedural protocols to improve results.