CHEER4TTE
The CPR, pre-hospital ECPR and early reperfusion study: A Target Trial Emulation (CHEER4 TTE)
A target trial emulation utilising retrospective, observational data from existing out of hospital cardiac arrest registries
Aim:
To determine whether prehospital extracorporeal cardiopulmonary resuscitation (ECPR) increases survival to hospital discharge in patients with refractory out of hospital cardiac arrest, as compared with conventional cardiac arrest care including salvage, hospital-based ECPR.
Rationale:
Survival after refractory OHCA remains extremely poor, with only around 2% of patients achieving neurologically favourable survival after prolonged conventional CPR. Although hospital-based extracorporeal cardiopulmonary resuscitation (ECPR) has shown promise, its effectiveness is highly dependent on rapid initiation, and outcomes worsen as low-flow time increases.
The hospital-based ECPR model is limited by delays associated with patient extrication and transport, reduced access for patients located further from ECPR centres, and substantial resource requirements. Prehospital ECPR has the potential to overcome these barriers by bringing ECMO directly to the patient, reducing low-flow times, maintaining high-quality CPR, and expanding access across a larger population.
Early international studies and Australian feasibility programs (CHEER3 and PRECARE) have demonstrated prehospital ECPR is feasible and suggest improved survival through earlier ECMO initiation. However, the current evidence is based largely on small observational studies that are vulnerable to bias and confounding.
Given the substantial costs, logistical complexity, and potential for both benefit and harm associated with ECPR programs, high-quality comparative effectiveness evidence is urgently needed to determine whether prehospital ECPR provides superior survival and neurological outcomes compared with standard cardiac arrest care and hospital-based ECPR in the Australian context.
Funding:
The project is funded by the Heart Foundation Vanguard Grant, 2022
Study Progress:
The study has been reviewed and approved by the Alfred Hospital Ethics Committee (103811/2024). Data access requests have been reviewed and approved by relevant data custodians.