Written by Michael Wolf
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Refractory out-of-hospital VF arrest has been considered almost uniformly fatal. ECMO rescue (ECPR) could change that, improving not just survival but good neurologic outcomes!
Why does this matter?
We want to be aggressive in resuscitation if that means a good outcome for patients. Does the heroic effort of adding ECMO to standard resuscitation lead to good functional neurological outcomes for patients?
“Hearts and Brains Too Good to Die”*
This was a pragmatic single-center trial in which 30 patients randomly received ECMO (ECPR) or standard ACLS for refractory (no ROSC after 3 shocks) out-of-hospital VF/VT cardiac arrest. Primary outcome was survival to hospital discharge.
Some notable exclusion criteria: >30 minute transport, trauma, burn, drug overdose, and GI bleeding. Those with ROSC after the 4th shock were still included. The ECMO group was brought immediately to the cath lab and cannulated to veno-arterial ECMO.
30 patients (15 per group) were enrolled. By random chance, the ACLS group had more patients with coronary artery disease, hypertension, smoking, hypertension and β-blocker prescriptions. Coronary occlusion was seen in 2/13 patients cannulated to ECMO and both patients who had ROSC after ACLS. Arrest characteristics, transport time, and presenting ABG appeared similar between groups. In the ECMO group, two patients were pronounced dead based on metabolic criteria, without being cannulated.
In the first planned interim analysis, the ECMO group had a higher rate of survival to hospital discharge: 6 (43%) vs. 1 (7%). That yielded a Bayesian posterior probability of 0.9861, and the study was terminated early given strong evidence of ECMO superiority over standard ACLS. The ECMO group also had better cumulative survival. None of the ACLS group survived to the 3-month mark. Neurologic outcome improved in all survivors in the ECMO group. All had a modified Rankin scale of 3 or less at 6 months, meaning that all could walk without assistance, but some required assistance with activities of daily living.
These are potentially paradigm-shifting results, with two big caveats. 1) This reflects care at a single center with an established ECMO program. Numbers might differ in different settings and populations. 2) ECMO cannulation was done by cardiologists in the cath lab, which is not standard. The authors acknowledge the importance of organized systems to make ECMO possible in the emergency department setting (see below for more).
Logistics
ECPR in the ED is a relatively new concept, with about 1/3 of ECMO centers offering it , without universally accepted criteria. ECMO is a team sport, requiring close collaboration between departments (prehospital/EMS, EM, critical care, surgery), nursing, perfusion, pharmacy, lab, subspecialty support (i.e. neurology, hematology, rehab). If you’re looking to expand your emergency department’s ability to provide ECMO/ECPR/ECLS, reach out to these colleagues and check out resources through ELSO, and ACEP.
*Title quote: Peter Safar, the architect of CPR (originally cardio-pulmonary-cerebral resuscitation), began his work after his daughter died of status asthmaticus. He aimed to promote meaningful survival of cardiac arrest, in part by empowering first responders in the field. I can’t help but think he would have approved of this work.
Source
Advanced reperfusion strategies for patients with out-of-hospital cardiac arrest and refractory ventricular fibrillation (ARREST): a phase 2, single centre, open-label, randomised controlled trial. Lancet. 2020 Dec 5;396(10265):1807-1816. doi: 10.1016/S0140-6736(20)32338-2. Epub 2020 Nov 13.
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