ECPR

ECPR is defined as VA -ECMO cannulation during refractory cardiac arrest. Refractory cardiac arrest is considered as the absence of ROSC despite provision of appropriate CPR for 15 - 30 min.

ECMO System

• Cannulae for vascular access - (Draining cannulae 21-27Fr; Returning cannulae 15-19 Fr)
• Line
• Pump
• Oxygenator
• Heat exchanger
• Interface

• The draining cannula is connected to the pump.
• For adults, mostly centrifugal pumps are used to circulate the patient's blood through ECMO circuit and to provide pressure necessary to maintain a constant blood flow through the ECMO circuit and to provide the pressure necessary to maintain a constant blood flow throughout the ECMO system and back ti the patient.

• Oxygenator consists of a semipermeable membrane that allows gas exchange to occur. This core component of ECMO is responsible for enriching oxygen and reducing carbon dioxide in the patients blood.

• The last part is the arterial cannula, a heat exchanger is also connected to the circuit to prevent hypothermia.
• The ECMO is controlled by an interface to provide feedback to healthcare team. 

Benefits

• VA ECMO pumps blood from the vein and returns it into an artery , thereby allowing the circulation of oxygenated and deoxygenated blood in the body even in the presence of cardiac arrest.
• ECPR improves Coronary perfusion pressure, rate of ROSC, rate of sucessful defibrillation. 
• The use of heat exchanger also helps to achieve TTM.

Complications

• Bleeding- Cannulation site, IC or GI Bleed  (8 -70%)
• Unsuccessful Cannulation (2-51%)
• Limb Ischemia (3-15%)
• Infection (8 -22%)

Inclusion criteria 

Timing of  CPR

• Observations from studies suggest a transition from CCPR to ECPR by 12 minutes.
• Survival declines over time, hence it is accepted to perform early ECPR to reduce low flow state and improve outcome.

Recommendation

• AHA/ILCOR 2023 Updates  suggests to consider ECPR as reasonable option in select patients with refractory cardiac arrest.

Recent Evidences

ARREST Trial (Lancet. 2020)

• It is single centre, open label RCT done to assess whether ECPR improved survival in OHCA with refractory VF compared to standard ACLS. The study was stopped prematurely due to superiority.
• Survival to hospital discharge was observed in one (7%) of 15 patients (95% credible interval 1·6–30·2) in the standard ACLS treatment group versus six (43%) of 14 patients (21·3–67·7) in the early ECMO-facilitated resuscitation group. 
• Study concluded that Early ECMO-facilitated resuscitation for patients with OHCA and refractory  ventricular fibrillation significantly improved survival to hospital discharge compared with  standard ACLS treatment.

PRAGUE Trial (JAMA. 2022)

• It is single centre, RCT done to assess whether a bundle of early intra arrest transport, ECPR and immediate invasive assessment and treatment improves survival with neurologically favourable outcome at 180 days.
• The trial was stopped at the recommendation of the data and safety monitoring board when prespecified criteria for futility were met. In the main analysis, 39 patients (31.5%) in the invasive strategy group and 29 (22.0%) in the standard strategy group survived to 180 days with good neurologic outcome (odds ratio [OR], 1.63 [95% CI, 0.93 to 2.85]; difference, 9.5% [95% CI, −1.3% to 20.1%]; P = .09). 
• Study concluded that Among patients with refractory out-of-hospital cardiac arrest,the bundle of early intra-arrest transport, ECPR, and invasive assessment and treatment  did not significantly improve survival with neurologically favorable outcome at 180 days compared with standard resuscitation. However, the trial was possibly underpowered to detect a clinically relevant difference.

INCEPTION Trial (NEJM. 2023)

• It is multicentric, RCT done to assess whether ECPR improved survival with favourable neurological outcome.
• At 30 days, 14 patients (20%) out of 70 in the extracorporeal-CPR group were alive with a favorable neurologic outcome, as compared with 10 patients (16%) out of 64 in the conventional-CPR group (odds ratio, 1.4; 95% confidence interval, 0.5 to 3.5; P=0.5. 
• In patients with refractory out-of-hospital cardiac arrest, extracorporeal CPR and conventional CPR had similar effects on survival with a favorable neurologic outcome.

Reference

• Wengenmayer, T., Tigges, E. & Staudacher, D.L. Extracorporeal cardiopulmonary resuscitation in 2023. ICMx 11, 74 (2023). https://doi.org/10.1186/s40635-023-00558-8
• https://doi.org/10.1161/JAHA.119.015291